1 // SPDX-License-Identifier: GPL-2.0+ 2 /* 3 * Driver for AMBA serial ports 4 * 5 * Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o. 6 * 7 * Copyright 1999 ARM Limited 8 * Copyright (C) 2000 Deep Blue Solutions Ltd. 9 * Copyright (C) 2010 ST-Ericsson SA 10 * 11 * This is a generic driver for ARM AMBA-type serial ports. They 12 * have a lot of 16550-like features, but are not register compatible. 13 * Note that although they do have CTS, DCD and DSR inputs, they do 14 * not have an RI input, nor do they have DTR or RTS outputs. If 15 * required, these have to be supplied via some other means (eg, GPIO) 16 * and hooked into this driver. 17 */ 18 19 #include <linux/module.h> 20 #include <linux/ioport.h> 21 #include <linux/init.h> 22 #include <linux/console.h> 23 #include <linux/sysrq.h> 24 #include <linux/device.h> 25 #include <linux/tty.h> 26 #include <linux/tty_flip.h> 27 #include <linux/serial_core.h> 28 #include <linux/serial.h> 29 #include <linux/amba/bus.h> 30 #include <linux/amba/serial.h> 31 #include <linux/clk.h> 32 #include <linux/slab.h> 33 #include <linux/dmaengine.h> 34 #include <linux/dma-mapping.h> 35 #include <linux/scatterlist.h> 36 #include <linux/delay.h> 37 #include <linux/types.h> 38 #include <linux/of.h> 39 #include <linux/of_device.h> 40 #include <linux/pinctrl/consumer.h> 41 #include <linux/sizes.h> 42 #include <linux/io.h> 43 #include <linux/acpi.h> 44 45 #define UART_NR 14 46 47 #define SERIAL_AMBA_MAJOR 204 48 #define SERIAL_AMBA_MINOR 64 49 #define SERIAL_AMBA_NR UART_NR 50 51 #define AMBA_ISR_PASS_LIMIT 256 52 53 #define UART_DR_ERROR (UART011_DR_OE|UART011_DR_BE|UART011_DR_PE|UART011_DR_FE) 54 #define UART_DUMMY_DR_RX (1 << 16) 55 56 enum { 57 REG_DR, 58 REG_ST_DMAWM, 59 REG_ST_TIMEOUT, 60 REG_FR, 61 REG_LCRH_RX, 62 REG_LCRH_TX, 63 REG_IBRD, 64 REG_FBRD, 65 REG_CR, 66 REG_IFLS, 67 REG_IMSC, 68 REG_RIS, 69 REG_MIS, 70 REG_ICR, 71 REG_DMACR, 72 REG_ST_XFCR, 73 REG_ST_XON1, 74 REG_ST_XON2, 75 REG_ST_XOFF1, 76 REG_ST_XOFF2, 77 REG_ST_ITCR, 78 REG_ST_ITIP, 79 REG_ST_ABCR, 80 REG_ST_ABIMSC, 81 82 /* The size of the array - must be last */ 83 REG_ARRAY_SIZE, 84 }; 85 86 static u16 pl011_std_offsets[REG_ARRAY_SIZE] = { 87 [REG_DR] = UART01x_DR, 88 [REG_FR] = UART01x_FR, 89 [REG_LCRH_RX] = UART011_LCRH, 90 [REG_LCRH_TX] = UART011_LCRH, 91 [REG_IBRD] = UART011_IBRD, 92 [REG_FBRD] = UART011_FBRD, 93 [REG_CR] = UART011_CR, 94 [REG_IFLS] = UART011_IFLS, 95 [REG_IMSC] = UART011_IMSC, 96 [REG_RIS] = UART011_RIS, 97 [REG_MIS] = UART011_MIS, 98 [REG_ICR] = UART011_ICR, 99 [REG_DMACR] = UART011_DMACR, 100 }; 101 102 /* There is by now at least one vendor with differing details, so handle it */ 103 struct vendor_data { 104 const u16 *reg_offset; 105 unsigned int ifls; 106 unsigned int fr_busy; 107 unsigned int fr_dsr; 108 unsigned int fr_cts; 109 unsigned int fr_ri; 110 unsigned int inv_fr; 111 bool access_32b; 112 bool oversampling; 113 bool dma_threshold; 114 bool cts_event_workaround; 115 bool always_enabled; 116 bool fixed_options; 117 118 unsigned int (*get_fifosize)(struct amba_device *dev); 119 }; 120 121 static unsigned int get_fifosize_arm(struct amba_device *dev) 122 { 123 return amba_rev(dev) < 3 ? 16 : 32; 124 } 125 126 static struct vendor_data vendor_arm = { 127 .reg_offset = pl011_std_offsets, 128 .ifls = UART011_IFLS_RX4_8|UART011_IFLS_TX4_8, 129 .fr_busy = UART01x_FR_BUSY, 130 .fr_dsr = UART01x_FR_DSR, 131 .fr_cts = UART01x_FR_CTS, 132 .fr_ri = UART011_FR_RI, 133 .oversampling = false, 134 .dma_threshold = false, 135 .cts_event_workaround = false, 136 .always_enabled = false, 137 .fixed_options = false, 138 .get_fifosize = get_fifosize_arm, 139 }; 140 141 static const struct vendor_data vendor_sbsa = { 142 .reg_offset = pl011_std_offsets, 143 .fr_busy = UART01x_FR_BUSY, 144 .fr_dsr = UART01x_FR_DSR, 145 .fr_cts = UART01x_FR_CTS, 146 .fr_ri = UART011_FR_RI, 147 .access_32b = true, 148 .oversampling = false, 149 .dma_threshold = false, 150 .cts_event_workaround = false, 151 .always_enabled = true, 152 .fixed_options = true, 153 }; 154 155 #ifdef CONFIG_ACPI_SPCR_TABLE 156 static const struct vendor_data vendor_qdt_qdf2400_e44 = { 157 .reg_offset = pl011_std_offsets, 158 .fr_busy = UART011_FR_TXFE, 159 .fr_dsr = UART01x_FR_DSR, 160 .fr_cts = UART01x_FR_CTS, 161 .fr_ri = UART011_FR_RI, 162 .inv_fr = UART011_FR_TXFE, 163 .access_32b = true, 164 .oversampling = false, 165 .dma_threshold = false, 166 .cts_event_workaround = false, 167 .always_enabled = true, 168 .fixed_options = true, 169 }; 170 #endif 171 172 static u16 pl011_st_offsets[REG_ARRAY_SIZE] = { 173 [REG_DR] = UART01x_DR, 174 [REG_ST_DMAWM] = ST_UART011_DMAWM, 175 [REG_ST_TIMEOUT] = ST_UART011_TIMEOUT, 176 [REG_FR] = UART01x_FR, 177 [REG_LCRH_RX] = ST_UART011_LCRH_RX, 178 [REG_LCRH_TX] = ST_UART011_LCRH_TX, 179 [REG_IBRD] = UART011_IBRD, 180 [REG_FBRD] = UART011_FBRD, 181 [REG_CR] = UART011_CR, 182 [REG_IFLS] = UART011_IFLS, 183 [REG_IMSC] = UART011_IMSC, 184 [REG_RIS] = UART011_RIS, 185 [REG_MIS] = UART011_MIS, 186 [REG_ICR] = UART011_ICR, 187 [REG_DMACR] = UART011_DMACR, 188 [REG_ST_XFCR] = ST_UART011_XFCR, 189 [REG_ST_XON1] = ST_UART011_XON1, 190 [REG_ST_XON2] = ST_UART011_XON2, 191 [REG_ST_XOFF1] = ST_UART011_XOFF1, 192 [REG_ST_XOFF2] = ST_UART011_XOFF2, 193 [REG_ST_ITCR] = ST_UART011_ITCR, 194 [REG_ST_ITIP] = ST_UART011_ITIP, 195 [REG_ST_ABCR] = ST_UART011_ABCR, 196 [REG_ST_ABIMSC] = ST_UART011_ABIMSC, 197 }; 198 199 static unsigned int get_fifosize_st(struct amba_device *dev) 200 { 201 return 64; 202 } 203 204 static struct vendor_data vendor_st = { 205 .reg_offset = pl011_st_offsets, 206 .ifls = UART011_IFLS_RX_HALF|UART011_IFLS_TX_HALF, 207 .fr_busy = UART01x_FR_BUSY, 208 .fr_dsr = UART01x_FR_DSR, 209 .fr_cts = UART01x_FR_CTS, 210 .fr_ri = UART011_FR_RI, 211 .oversampling = true, 212 .dma_threshold = true, 213 .cts_event_workaround = true, 214 .always_enabled = false, 215 .fixed_options = false, 216 .get_fifosize = get_fifosize_st, 217 }; 218 219 /* Deals with DMA transactions */ 220 221 struct pl011_sgbuf { 222 struct scatterlist sg; 223 char *buf; 224 }; 225 226 struct pl011_dmarx_data { 227 struct dma_chan *chan; 228 struct completion complete; 229 bool use_buf_b; 230 struct pl011_sgbuf sgbuf_a; 231 struct pl011_sgbuf sgbuf_b; 232 dma_cookie_t cookie; 233 bool running; 234 struct timer_list timer; 235 unsigned int last_residue; 236 unsigned long last_jiffies; 237 bool auto_poll_rate; 238 unsigned int poll_rate; 239 unsigned int poll_timeout; 240 }; 241 242 struct pl011_dmatx_data { 243 struct dma_chan *chan; 244 struct scatterlist sg; 245 char *buf; 246 bool queued; 247 }; 248 249 /* 250 * We wrap our port structure around the generic uart_port. 251 */ 252 struct uart_amba_port { 253 struct uart_port port; 254 const u16 *reg_offset; 255 struct clk *clk; 256 const struct vendor_data *vendor; 257 unsigned int dmacr; /* dma control reg */ 258 unsigned int im; /* interrupt mask */ 259 unsigned int old_status; 260 unsigned int fifosize; /* vendor-specific */ 261 unsigned int fixed_baud; /* vendor-set fixed baud rate */ 262 char type[12]; 263 bool rs485_tx_started; 264 unsigned int rs485_tx_drain_interval; /* usecs */ 265 #ifdef CONFIG_DMA_ENGINE 266 /* DMA stuff */ 267 bool using_tx_dma; 268 bool using_rx_dma; 269 struct pl011_dmarx_data dmarx; 270 struct pl011_dmatx_data dmatx; 271 bool dma_probed; 272 #endif 273 }; 274 275 static unsigned int pl011_tx_empty(struct uart_port *port); 276 277 static unsigned int pl011_reg_to_offset(const struct uart_amba_port *uap, 278 unsigned int reg) 279 { 280 return uap->reg_offset[reg]; 281 } 282 283 static unsigned int pl011_read(const struct uart_amba_port *uap, 284 unsigned int reg) 285 { 286 void __iomem *addr = uap->port.membase + pl011_reg_to_offset(uap, reg); 287 288 return (uap->port.iotype == UPIO_MEM32) ? 289 readl_relaxed(addr) : readw_relaxed(addr); 290 } 291 292 static void pl011_write(unsigned int val, const struct uart_amba_port *uap, 293 unsigned int reg) 294 { 295 void __iomem *addr = uap->port.membase + pl011_reg_to_offset(uap, reg); 296 297 if (uap->port.iotype == UPIO_MEM32) 298 writel_relaxed(val, addr); 299 else 300 writew_relaxed(val, addr); 301 } 302 303 /* 304 * Reads up to 256 characters from the FIFO or until it's empty and 305 * inserts them into the TTY layer. Returns the number of characters 306 * read from the FIFO. 307 */ 308 static int pl011_fifo_to_tty(struct uart_amba_port *uap) 309 { 310 unsigned int ch, flag, fifotaken; 311 int sysrq; 312 u16 status; 313 314 for (fifotaken = 0; fifotaken != 256; fifotaken++) { 315 status = pl011_read(uap, REG_FR); 316 if (status & UART01x_FR_RXFE) 317 break; 318 319 /* Take chars from the FIFO and update status */ 320 ch = pl011_read(uap, REG_DR) | UART_DUMMY_DR_RX; 321 flag = TTY_NORMAL; 322 uap->port.icount.rx++; 323 324 if (unlikely(ch & UART_DR_ERROR)) { 325 if (ch & UART011_DR_BE) { 326 ch &= ~(UART011_DR_FE | UART011_DR_PE); 327 uap->port.icount.brk++; 328 if (uart_handle_break(&uap->port)) 329 continue; 330 } else if (ch & UART011_DR_PE) 331 uap->port.icount.parity++; 332 else if (ch & UART011_DR_FE) 333 uap->port.icount.frame++; 334 if (ch & UART011_DR_OE) 335 uap->port.icount.overrun++; 336 337 ch &= uap->port.read_status_mask; 338 339 if (ch & UART011_DR_BE) 340 flag = TTY_BREAK; 341 else if (ch & UART011_DR_PE) 342 flag = TTY_PARITY; 343 else if (ch & UART011_DR_FE) 344 flag = TTY_FRAME; 345 } 346 347 spin_unlock(&uap->port.lock); 348 sysrq = uart_handle_sysrq_char(&uap->port, ch & 255); 349 spin_lock(&uap->port.lock); 350 351 if (!sysrq) 352 uart_insert_char(&uap->port, ch, UART011_DR_OE, ch, flag); 353 } 354 355 return fifotaken; 356 } 357 358 359 /* 360 * All the DMA operation mode stuff goes inside this ifdef. 361 * This assumes that you have a generic DMA device interface, 362 * no custom DMA interfaces are supported. 363 */ 364 #ifdef CONFIG_DMA_ENGINE 365 366 #define PL011_DMA_BUFFER_SIZE PAGE_SIZE 367 368 static int pl011_sgbuf_init(struct dma_chan *chan, struct pl011_sgbuf *sg, 369 enum dma_data_direction dir) 370 { 371 dma_addr_t dma_addr; 372 373 sg->buf = dma_alloc_coherent(chan->device->dev, 374 PL011_DMA_BUFFER_SIZE, &dma_addr, GFP_KERNEL); 375 if (!sg->buf) 376 return -ENOMEM; 377 378 sg_init_table(&sg->sg, 1); 379 sg_set_page(&sg->sg, phys_to_page(dma_addr), 380 PL011_DMA_BUFFER_SIZE, offset_in_page(dma_addr)); 381 sg_dma_address(&sg->sg) = dma_addr; 382 sg_dma_len(&sg->sg) = PL011_DMA_BUFFER_SIZE; 383 384 return 0; 385 } 386 387 static void pl011_sgbuf_free(struct dma_chan *chan, struct pl011_sgbuf *sg, 388 enum dma_data_direction dir) 389 { 390 if (sg->buf) { 391 dma_free_coherent(chan->device->dev, 392 PL011_DMA_BUFFER_SIZE, sg->buf, 393 sg_dma_address(&sg->sg)); 394 } 395 } 396 397 static void pl011_dma_probe(struct uart_amba_port *uap) 398 { 399 /* DMA is the sole user of the platform data right now */ 400 struct amba_pl011_data *plat = dev_get_platdata(uap->port.dev); 401 struct device *dev = uap->port.dev; 402 struct dma_slave_config tx_conf = { 403 .dst_addr = uap->port.mapbase + 404 pl011_reg_to_offset(uap, REG_DR), 405 .dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE, 406 .direction = DMA_MEM_TO_DEV, 407 .dst_maxburst = uap->fifosize >> 1, 408 .device_fc = false, 409 }; 410 struct dma_chan *chan; 411 dma_cap_mask_t mask; 412 413 uap->dma_probed = true; 414 chan = dma_request_chan(dev, "tx"); 415 if (IS_ERR(chan)) { 416 if (PTR_ERR(chan) == -EPROBE_DEFER) { 417 uap->dma_probed = false; 418 return; 419 } 420 421 /* We need platform data */ 422 if (!plat || !plat->dma_filter) { 423 dev_info(uap->port.dev, "no DMA platform data\n"); 424 return; 425 } 426 427 /* Try to acquire a generic DMA engine slave TX channel */ 428 dma_cap_zero(mask); 429 dma_cap_set(DMA_SLAVE, mask); 430 431 chan = dma_request_channel(mask, plat->dma_filter, 432 plat->dma_tx_param); 433 if (!chan) { 434 dev_err(uap->port.dev, "no TX DMA channel!\n"); 435 return; 436 } 437 } 438 439 dmaengine_slave_config(chan, &tx_conf); 440 uap->dmatx.chan = chan; 441 442 dev_info(uap->port.dev, "DMA channel TX %s\n", 443 dma_chan_name(uap->dmatx.chan)); 444 445 /* Optionally make use of an RX channel as well */ 446 chan = dma_request_slave_channel(dev, "rx"); 447 448 if (!chan && plat && plat->dma_rx_param) { 449 chan = dma_request_channel(mask, plat->dma_filter, plat->dma_rx_param); 450 451 if (!chan) { 452 dev_err(uap->port.dev, "no RX DMA channel!\n"); 453 return; 454 } 455 } 456 457 if (chan) { 458 struct dma_slave_config rx_conf = { 459 .src_addr = uap->port.mapbase + 460 pl011_reg_to_offset(uap, REG_DR), 461 .src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE, 462 .direction = DMA_DEV_TO_MEM, 463 .src_maxburst = uap->fifosize >> 2, 464 .device_fc = false, 465 }; 466 struct dma_slave_caps caps; 467 468 /* 469 * Some DMA controllers provide information on their capabilities. 470 * If the controller does, check for suitable residue processing 471 * otherwise assime all is well. 472 */ 473 if (0 == dma_get_slave_caps(chan, &caps)) { 474 if (caps.residue_granularity == 475 DMA_RESIDUE_GRANULARITY_DESCRIPTOR) { 476 dma_release_channel(chan); 477 dev_info(uap->port.dev, 478 "RX DMA disabled - no residue processing\n"); 479 return; 480 } 481 } 482 dmaengine_slave_config(chan, &rx_conf); 483 uap->dmarx.chan = chan; 484 485 uap->dmarx.auto_poll_rate = false; 486 if (plat && plat->dma_rx_poll_enable) { 487 /* Set poll rate if specified. */ 488 if (plat->dma_rx_poll_rate) { 489 uap->dmarx.auto_poll_rate = false; 490 uap->dmarx.poll_rate = plat->dma_rx_poll_rate; 491 } else { 492 /* 493 * 100 ms defaults to poll rate if not 494 * specified. This will be adjusted with 495 * the baud rate at set_termios. 496 */ 497 uap->dmarx.auto_poll_rate = true; 498 uap->dmarx.poll_rate = 100; 499 } 500 /* 3 secs defaults poll_timeout if not specified. */ 501 if (plat->dma_rx_poll_timeout) 502 uap->dmarx.poll_timeout = 503 plat->dma_rx_poll_timeout; 504 else 505 uap->dmarx.poll_timeout = 3000; 506 } else if (!plat && dev->of_node) { 507 uap->dmarx.auto_poll_rate = of_property_read_bool( 508 dev->of_node, "auto-poll"); 509 if (uap->dmarx.auto_poll_rate) { 510 u32 x; 511 512 if (0 == of_property_read_u32(dev->of_node, 513 "poll-rate-ms", &x)) 514 uap->dmarx.poll_rate = x; 515 else 516 uap->dmarx.poll_rate = 100; 517 if (0 == of_property_read_u32(dev->of_node, 518 "poll-timeout-ms", &x)) 519 uap->dmarx.poll_timeout = x; 520 else 521 uap->dmarx.poll_timeout = 3000; 522 } 523 } 524 dev_info(uap->port.dev, "DMA channel RX %s\n", 525 dma_chan_name(uap->dmarx.chan)); 526 } 527 } 528 529 static void pl011_dma_remove(struct uart_amba_port *uap) 530 { 531 if (uap->dmatx.chan) 532 dma_release_channel(uap->dmatx.chan); 533 if (uap->dmarx.chan) 534 dma_release_channel(uap->dmarx.chan); 535 } 536 537 /* Forward declare these for the refill routine */ 538 static int pl011_dma_tx_refill(struct uart_amba_port *uap); 539 static void pl011_start_tx_pio(struct uart_amba_port *uap); 540 541 /* 542 * The current DMA TX buffer has been sent. 543 * Try to queue up another DMA buffer. 544 */ 545 static void pl011_dma_tx_callback(void *data) 546 { 547 struct uart_amba_port *uap = data; 548 struct pl011_dmatx_data *dmatx = &uap->dmatx; 549 unsigned long flags; 550 u16 dmacr; 551 552 spin_lock_irqsave(&uap->port.lock, flags); 553 if (uap->dmatx.queued) 554 dma_unmap_sg(dmatx->chan->device->dev, &dmatx->sg, 1, 555 DMA_TO_DEVICE); 556 557 dmacr = uap->dmacr; 558 uap->dmacr = dmacr & ~UART011_TXDMAE; 559 pl011_write(uap->dmacr, uap, REG_DMACR); 560 561 /* 562 * If TX DMA was disabled, it means that we've stopped the DMA for 563 * some reason (eg, XOFF received, or we want to send an X-char.) 564 * 565 * Note: we need to be careful here of a potential race between DMA 566 * and the rest of the driver - if the driver disables TX DMA while 567 * a TX buffer completing, we must update the tx queued status to 568 * get further refills (hence we check dmacr). 569 */ 570 if (!(dmacr & UART011_TXDMAE) || uart_tx_stopped(&uap->port) || 571 uart_circ_empty(&uap->port.state->xmit)) { 572 uap->dmatx.queued = false; 573 spin_unlock_irqrestore(&uap->port.lock, flags); 574 return; 575 } 576 577 if (pl011_dma_tx_refill(uap) <= 0) 578 /* 579 * We didn't queue a DMA buffer for some reason, but we 580 * have data pending to be sent. Re-enable the TX IRQ. 581 */ 582 pl011_start_tx_pio(uap); 583 584 spin_unlock_irqrestore(&uap->port.lock, flags); 585 } 586 587 /* 588 * Try to refill the TX DMA buffer. 589 * Locking: called with port lock held and IRQs disabled. 590 * Returns: 591 * 1 if we queued up a TX DMA buffer. 592 * 0 if we didn't want to handle this by DMA 593 * <0 on error 594 */ 595 static int pl011_dma_tx_refill(struct uart_amba_port *uap) 596 { 597 struct pl011_dmatx_data *dmatx = &uap->dmatx; 598 struct dma_chan *chan = dmatx->chan; 599 struct dma_device *dma_dev = chan->device; 600 struct dma_async_tx_descriptor *desc; 601 struct circ_buf *xmit = &uap->port.state->xmit; 602 unsigned int count; 603 604 /* 605 * Try to avoid the overhead involved in using DMA if the 606 * transaction fits in the first half of the FIFO, by using 607 * the standard interrupt handling. This ensures that we 608 * issue a uart_write_wakeup() at the appropriate time. 609 */ 610 count = uart_circ_chars_pending(xmit); 611 if (count < (uap->fifosize >> 1)) { 612 uap->dmatx.queued = false; 613 return 0; 614 } 615 616 /* 617 * Bodge: don't send the last character by DMA, as this 618 * will prevent XON from notifying us to restart DMA. 619 */ 620 count -= 1; 621 622 /* Else proceed to copy the TX chars to the DMA buffer and fire DMA */ 623 if (count > PL011_DMA_BUFFER_SIZE) 624 count = PL011_DMA_BUFFER_SIZE; 625 626 if (xmit->tail < xmit->head) 627 memcpy(&dmatx->buf[0], &xmit->buf[xmit->tail], count); 628 else { 629 size_t first = UART_XMIT_SIZE - xmit->tail; 630 size_t second; 631 632 if (first > count) 633 first = count; 634 second = count - first; 635 636 memcpy(&dmatx->buf[0], &xmit->buf[xmit->tail], first); 637 if (second) 638 memcpy(&dmatx->buf[first], &xmit->buf[0], second); 639 } 640 641 dmatx->sg.length = count; 642 643 if (dma_map_sg(dma_dev->dev, &dmatx->sg, 1, DMA_TO_DEVICE) != 1) { 644 uap->dmatx.queued = false; 645 dev_dbg(uap->port.dev, "unable to map TX DMA\n"); 646 return -EBUSY; 647 } 648 649 desc = dmaengine_prep_slave_sg(chan, &dmatx->sg, 1, DMA_MEM_TO_DEV, 650 DMA_PREP_INTERRUPT | DMA_CTRL_ACK); 651 if (!desc) { 652 dma_unmap_sg(dma_dev->dev, &dmatx->sg, 1, DMA_TO_DEVICE); 653 uap->dmatx.queued = false; 654 /* 655 * If DMA cannot be used right now, we complete this 656 * transaction via IRQ and let the TTY layer retry. 657 */ 658 dev_dbg(uap->port.dev, "TX DMA busy\n"); 659 return -EBUSY; 660 } 661 662 /* Some data to go along to the callback */ 663 desc->callback = pl011_dma_tx_callback; 664 desc->callback_param = uap; 665 666 /* All errors should happen at prepare time */ 667 dmaengine_submit(desc); 668 669 /* Fire the DMA transaction */ 670 dma_dev->device_issue_pending(chan); 671 672 uap->dmacr |= UART011_TXDMAE; 673 pl011_write(uap->dmacr, uap, REG_DMACR); 674 uap->dmatx.queued = true; 675 676 /* 677 * Now we know that DMA will fire, so advance the ring buffer 678 * with the stuff we just dispatched. 679 */ 680 uart_xmit_advance(&uap->port, count); 681 682 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) 683 uart_write_wakeup(&uap->port); 684 685 return 1; 686 } 687 688 /* 689 * We received a transmit interrupt without a pending X-char but with 690 * pending characters. 691 * Locking: called with port lock held and IRQs disabled. 692 * Returns: 693 * false if we want to use PIO to transmit 694 * true if we queued a DMA buffer 695 */ 696 static bool pl011_dma_tx_irq(struct uart_amba_port *uap) 697 { 698 if (!uap->using_tx_dma) 699 return false; 700 701 /* 702 * If we already have a TX buffer queued, but received a 703 * TX interrupt, it will be because we've just sent an X-char. 704 * Ensure the TX DMA is enabled and the TX IRQ is disabled. 705 */ 706 if (uap->dmatx.queued) { 707 uap->dmacr |= UART011_TXDMAE; 708 pl011_write(uap->dmacr, uap, REG_DMACR); 709 uap->im &= ~UART011_TXIM; 710 pl011_write(uap->im, uap, REG_IMSC); 711 return true; 712 } 713 714 /* 715 * We don't have a TX buffer queued, so try to queue one. 716 * If we successfully queued a buffer, mask the TX IRQ. 717 */ 718 if (pl011_dma_tx_refill(uap) > 0) { 719 uap->im &= ~UART011_TXIM; 720 pl011_write(uap->im, uap, REG_IMSC); 721 return true; 722 } 723 return false; 724 } 725 726 /* 727 * Stop the DMA transmit (eg, due to received XOFF). 728 * Locking: called with port lock held and IRQs disabled. 729 */ 730 static inline void pl011_dma_tx_stop(struct uart_amba_port *uap) 731 { 732 if (uap->dmatx.queued) { 733 uap->dmacr &= ~UART011_TXDMAE; 734 pl011_write(uap->dmacr, uap, REG_DMACR); 735 } 736 } 737 738 /* 739 * Try to start a DMA transmit, or in the case of an XON/OFF 740 * character queued for send, try to get that character out ASAP. 741 * Locking: called with port lock held and IRQs disabled. 742 * Returns: 743 * false if we want the TX IRQ to be enabled 744 * true if we have a buffer queued 745 */ 746 static inline bool pl011_dma_tx_start(struct uart_amba_port *uap) 747 { 748 u16 dmacr; 749 750 if (!uap->using_tx_dma) 751 return false; 752 753 if (!uap->port.x_char) { 754 /* no X-char, try to push chars out in DMA mode */ 755 bool ret = true; 756 757 if (!uap->dmatx.queued) { 758 if (pl011_dma_tx_refill(uap) > 0) { 759 uap->im &= ~UART011_TXIM; 760 pl011_write(uap->im, uap, REG_IMSC); 761 } else 762 ret = false; 763 } else if (!(uap->dmacr & UART011_TXDMAE)) { 764 uap->dmacr |= UART011_TXDMAE; 765 pl011_write(uap->dmacr, uap, REG_DMACR); 766 } 767 return ret; 768 } 769 770 /* 771 * We have an X-char to send. Disable DMA to prevent it loading 772 * the TX fifo, and then see if we can stuff it into the FIFO. 773 */ 774 dmacr = uap->dmacr; 775 uap->dmacr &= ~UART011_TXDMAE; 776 pl011_write(uap->dmacr, uap, REG_DMACR); 777 778 if (pl011_read(uap, REG_FR) & UART01x_FR_TXFF) { 779 /* 780 * No space in the FIFO, so enable the transmit interrupt 781 * so we know when there is space. Note that once we've 782 * loaded the character, we should just re-enable DMA. 783 */ 784 return false; 785 } 786 787 pl011_write(uap->port.x_char, uap, REG_DR); 788 uap->port.icount.tx++; 789 uap->port.x_char = 0; 790 791 /* Success - restore the DMA state */ 792 uap->dmacr = dmacr; 793 pl011_write(dmacr, uap, REG_DMACR); 794 795 return true; 796 } 797 798 /* 799 * Flush the transmit buffer. 800 * Locking: called with port lock held and IRQs disabled. 801 */ 802 static void pl011_dma_flush_buffer(struct uart_port *port) 803 __releases(&uap->port.lock) 804 __acquires(&uap->port.lock) 805 { 806 struct uart_amba_port *uap = 807 container_of(port, struct uart_amba_port, port); 808 809 if (!uap->using_tx_dma) 810 return; 811 812 dmaengine_terminate_async(uap->dmatx.chan); 813 814 if (uap->dmatx.queued) { 815 dma_unmap_sg(uap->dmatx.chan->device->dev, &uap->dmatx.sg, 1, 816 DMA_TO_DEVICE); 817 uap->dmatx.queued = false; 818 uap->dmacr &= ~UART011_TXDMAE; 819 pl011_write(uap->dmacr, uap, REG_DMACR); 820 } 821 } 822 823 static void pl011_dma_rx_callback(void *data); 824 825 static int pl011_dma_rx_trigger_dma(struct uart_amba_port *uap) 826 { 827 struct dma_chan *rxchan = uap->dmarx.chan; 828 struct pl011_dmarx_data *dmarx = &uap->dmarx; 829 struct dma_async_tx_descriptor *desc; 830 struct pl011_sgbuf *sgbuf; 831 832 if (!rxchan) 833 return -EIO; 834 835 /* Start the RX DMA job */ 836 sgbuf = uap->dmarx.use_buf_b ? 837 &uap->dmarx.sgbuf_b : &uap->dmarx.sgbuf_a; 838 desc = dmaengine_prep_slave_sg(rxchan, &sgbuf->sg, 1, 839 DMA_DEV_TO_MEM, 840 DMA_PREP_INTERRUPT | DMA_CTRL_ACK); 841 /* 842 * If the DMA engine is busy and cannot prepare a 843 * channel, no big deal, the driver will fall back 844 * to interrupt mode as a result of this error code. 845 */ 846 if (!desc) { 847 uap->dmarx.running = false; 848 dmaengine_terminate_all(rxchan); 849 return -EBUSY; 850 } 851 852 /* Some data to go along to the callback */ 853 desc->callback = pl011_dma_rx_callback; 854 desc->callback_param = uap; 855 dmarx->cookie = dmaengine_submit(desc); 856 dma_async_issue_pending(rxchan); 857 858 uap->dmacr |= UART011_RXDMAE; 859 pl011_write(uap->dmacr, uap, REG_DMACR); 860 uap->dmarx.running = true; 861 862 uap->im &= ~UART011_RXIM; 863 pl011_write(uap->im, uap, REG_IMSC); 864 865 return 0; 866 } 867 868 /* 869 * This is called when either the DMA job is complete, or 870 * the FIFO timeout interrupt occurred. This must be called 871 * with the port spinlock uap->port.lock held. 872 */ 873 static void pl011_dma_rx_chars(struct uart_amba_port *uap, 874 u32 pending, bool use_buf_b, 875 bool readfifo) 876 { 877 struct tty_port *port = &uap->port.state->port; 878 struct pl011_sgbuf *sgbuf = use_buf_b ? 879 &uap->dmarx.sgbuf_b : &uap->dmarx.sgbuf_a; 880 int dma_count = 0; 881 u32 fifotaken = 0; /* only used for vdbg() */ 882 883 struct pl011_dmarx_data *dmarx = &uap->dmarx; 884 int dmataken = 0; 885 886 if (uap->dmarx.poll_rate) { 887 /* The data can be taken by polling */ 888 dmataken = sgbuf->sg.length - dmarx->last_residue; 889 /* Recalculate the pending size */ 890 if (pending >= dmataken) 891 pending -= dmataken; 892 } 893 894 /* Pick the remain data from the DMA */ 895 if (pending) { 896 897 /* 898 * First take all chars in the DMA pipe, then look in the FIFO. 899 * Note that tty_insert_flip_buf() tries to take as many chars 900 * as it can. 901 */ 902 dma_count = tty_insert_flip_string(port, sgbuf->buf + dmataken, 903 pending); 904 905 uap->port.icount.rx += dma_count; 906 if (dma_count < pending) 907 dev_warn(uap->port.dev, 908 "couldn't insert all characters (TTY is full?)\n"); 909 } 910 911 /* Reset the last_residue for Rx DMA poll */ 912 if (uap->dmarx.poll_rate) 913 dmarx->last_residue = sgbuf->sg.length; 914 915 /* 916 * Only continue with trying to read the FIFO if all DMA chars have 917 * been taken first. 918 */ 919 if (dma_count == pending && readfifo) { 920 /* Clear any error flags */ 921 pl011_write(UART011_OEIS | UART011_BEIS | UART011_PEIS | 922 UART011_FEIS, uap, REG_ICR); 923 924 /* 925 * If we read all the DMA'd characters, and we had an 926 * incomplete buffer, that could be due to an rx error, or 927 * maybe we just timed out. Read any pending chars and check 928 * the error status. 929 * 930 * Error conditions will only occur in the FIFO, these will 931 * trigger an immediate interrupt and stop the DMA job, so we 932 * will always find the error in the FIFO, never in the DMA 933 * buffer. 934 */ 935 fifotaken = pl011_fifo_to_tty(uap); 936 } 937 938 dev_vdbg(uap->port.dev, 939 "Took %d chars from DMA buffer and %d chars from the FIFO\n", 940 dma_count, fifotaken); 941 tty_flip_buffer_push(port); 942 } 943 944 static void pl011_dma_rx_irq(struct uart_amba_port *uap) 945 { 946 struct pl011_dmarx_data *dmarx = &uap->dmarx; 947 struct dma_chan *rxchan = dmarx->chan; 948 struct pl011_sgbuf *sgbuf = dmarx->use_buf_b ? 949 &dmarx->sgbuf_b : &dmarx->sgbuf_a; 950 size_t pending; 951 struct dma_tx_state state; 952 enum dma_status dmastat; 953 954 /* 955 * Pause the transfer so we can trust the current counter, 956 * do this before we pause the PL011 block, else we may 957 * overflow the FIFO. 958 */ 959 if (dmaengine_pause(rxchan)) 960 dev_err(uap->port.dev, "unable to pause DMA transfer\n"); 961 dmastat = rxchan->device->device_tx_status(rxchan, 962 dmarx->cookie, &state); 963 if (dmastat != DMA_PAUSED) 964 dev_err(uap->port.dev, "unable to pause DMA transfer\n"); 965 966 /* Disable RX DMA - incoming data will wait in the FIFO */ 967 uap->dmacr &= ~UART011_RXDMAE; 968 pl011_write(uap->dmacr, uap, REG_DMACR); 969 uap->dmarx.running = false; 970 971 pending = sgbuf->sg.length - state.residue; 972 BUG_ON(pending > PL011_DMA_BUFFER_SIZE); 973 /* Then we terminate the transfer - we now know our residue */ 974 dmaengine_terminate_all(rxchan); 975 976 /* 977 * This will take the chars we have so far and insert 978 * into the framework. 979 */ 980 pl011_dma_rx_chars(uap, pending, dmarx->use_buf_b, true); 981 982 /* Switch buffer & re-trigger DMA job */ 983 dmarx->use_buf_b = !dmarx->use_buf_b; 984 if (pl011_dma_rx_trigger_dma(uap)) { 985 dev_dbg(uap->port.dev, "could not retrigger RX DMA job " 986 "fall back to interrupt mode\n"); 987 uap->im |= UART011_RXIM; 988 pl011_write(uap->im, uap, REG_IMSC); 989 } 990 } 991 992 static void pl011_dma_rx_callback(void *data) 993 { 994 struct uart_amba_port *uap = data; 995 struct pl011_dmarx_data *dmarx = &uap->dmarx; 996 struct dma_chan *rxchan = dmarx->chan; 997 bool lastbuf = dmarx->use_buf_b; 998 struct pl011_sgbuf *sgbuf = dmarx->use_buf_b ? 999 &dmarx->sgbuf_b : &dmarx->sgbuf_a; 1000 size_t pending; 1001 struct dma_tx_state state; 1002 int ret; 1003 1004 /* 1005 * This completion interrupt occurs typically when the 1006 * RX buffer is totally stuffed but no timeout has yet 1007 * occurred. When that happens, we just want the RX 1008 * routine to flush out the secondary DMA buffer while 1009 * we immediately trigger the next DMA job. 1010 */ 1011 spin_lock_irq(&uap->port.lock); 1012 /* 1013 * Rx data can be taken by the UART interrupts during 1014 * the DMA irq handler. So we check the residue here. 1015 */ 1016 rxchan->device->device_tx_status(rxchan, dmarx->cookie, &state); 1017 pending = sgbuf->sg.length - state.residue; 1018 BUG_ON(pending > PL011_DMA_BUFFER_SIZE); 1019 /* Then we terminate the transfer - we now know our residue */ 1020 dmaengine_terminate_all(rxchan); 1021 1022 uap->dmarx.running = false; 1023 dmarx->use_buf_b = !lastbuf; 1024 ret = pl011_dma_rx_trigger_dma(uap); 1025 1026 pl011_dma_rx_chars(uap, pending, lastbuf, false); 1027 spin_unlock_irq(&uap->port.lock); 1028 /* 1029 * Do this check after we picked the DMA chars so we don't 1030 * get some IRQ immediately from RX. 1031 */ 1032 if (ret) { 1033 dev_dbg(uap->port.dev, "could not retrigger RX DMA job " 1034 "fall back to interrupt mode\n"); 1035 uap->im |= UART011_RXIM; 1036 pl011_write(uap->im, uap, REG_IMSC); 1037 } 1038 } 1039 1040 /* 1041 * Stop accepting received characters, when we're shutting down or 1042 * suspending this port. 1043 * Locking: called with port lock held and IRQs disabled. 1044 */ 1045 static inline void pl011_dma_rx_stop(struct uart_amba_port *uap) 1046 { 1047 if (!uap->using_rx_dma) 1048 return; 1049 1050 /* FIXME. Just disable the DMA enable */ 1051 uap->dmacr &= ~UART011_RXDMAE; 1052 pl011_write(uap->dmacr, uap, REG_DMACR); 1053 } 1054 1055 /* 1056 * Timer handler for Rx DMA polling. 1057 * Every polling, It checks the residue in the dma buffer and transfer 1058 * data to the tty. Also, last_residue is updated for the next polling. 1059 */ 1060 static void pl011_dma_rx_poll(struct timer_list *t) 1061 { 1062 struct uart_amba_port *uap = from_timer(uap, t, dmarx.timer); 1063 struct tty_port *port = &uap->port.state->port; 1064 struct pl011_dmarx_data *dmarx = &uap->dmarx; 1065 struct dma_chan *rxchan = uap->dmarx.chan; 1066 unsigned long flags; 1067 unsigned int dmataken = 0; 1068 unsigned int size = 0; 1069 struct pl011_sgbuf *sgbuf; 1070 int dma_count; 1071 struct dma_tx_state state; 1072 1073 sgbuf = dmarx->use_buf_b ? &uap->dmarx.sgbuf_b : &uap->dmarx.sgbuf_a; 1074 rxchan->device->device_tx_status(rxchan, dmarx->cookie, &state); 1075 if (likely(state.residue < dmarx->last_residue)) { 1076 dmataken = sgbuf->sg.length - dmarx->last_residue; 1077 size = dmarx->last_residue - state.residue; 1078 dma_count = tty_insert_flip_string(port, sgbuf->buf + dmataken, 1079 size); 1080 if (dma_count == size) 1081 dmarx->last_residue = state.residue; 1082 dmarx->last_jiffies = jiffies; 1083 } 1084 tty_flip_buffer_push(port); 1085 1086 /* 1087 * If no data is received in poll_timeout, the driver will fall back 1088 * to interrupt mode. We will retrigger DMA at the first interrupt. 1089 */ 1090 if (jiffies_to_msecs(jiffies - dmarx->last_jiffies) 1091 > uap->dmarx.poll_timeout) { 1092 1093 spin_lock_irqsave(&uap->port.lock, flags); 1094 pl011_dma_rx_stop(uap); 1095 uap->im |= UART011_RXIM; 1096 pl011_write(uap->im, uap, REG_IMSC); 1097 spin_unlock_irqrestore(&uap->port.lock, flags); 1098 1099 uap->dmarx.running = false; 1100 dmaengine_terminate_all(rxchan); 1101 del_timer(&uap->dmarx.timer); 1102 } else { 1103 mod_timer(&uap->dmarx.timer, 1104 jiffies + msecs_to_jiffies(uap->dmarx.poll_rate)); 1105 } 1106 } 1107 1108 static void pl011_dma_startup(struct uart_amba_port *uap) 1109 { 1110 int ret; 1111 1112 if (!uap->dma_probed) 1113 pl011_dma_probe(uap); 1114 1115 if (!uap->dmatx.chan) 1116 return; 1117 1118 uap->dmatx.buf = kmalloc(PL011_DMA_BUFFER_SIZE, GFP_KERNEL | __GFP_DMA); 1119 if (!uap->dmatx.buf) { 1120 dev_err(uap->port.dev, "no memory for DMA TX buffer\n"); 1121 uap->port.fifosize = uap->fifosize; 1122 return; 1123 } 1124 1125 sg_init_one(&uap->dmatx.sg, uap->dmatx.buf, PL011_DMA_BUFFER_SIZE); 1126 1127 /* The DMA buffer is now the FIFO the TTY subsystem can use */ 1128 uap->port.fifosize = PL011_DMA_BUFFER_SIZE; 1129 uap->using_tx_dma = true; 1130 1131 if (!uap->dmarx.chan) 1132 goto skip_rx; 1133 1134 /* Allocate and map DMA RX buffers */ 1135 ret = pl011_sgbuf_init(uap->dmarx.chan, &uap->dmarx.sgbuf_a, 1136 DMA_FROM_DEVICE); 1137 if (ret) { 1138 dev_err(uap->port.dev, "failed to init DMA %s: %d\n", 1139 "RX buffer A", ret); 1140 goto skip_rx; 1141 } 1142 1143 ret = pl011_sgbuf_init(uap->dmarx.chan, &uap->dmarx.sgbuf_b, 1144 DMA_FROM_DEVICE); 1145 if (ret) { 1146 dev_err(uap->port.dev, "failed to init DMA %s: %d\n", 1147 "RX buffer B", ret); 1148 pl011_sgbuf_free(uap->dmarx.chan, &uap->dmarx.sgbuf_a, 1149 DMA_FROM_DEVICE); 1150 goto skip_rx; 1151 } 1152 1153 uap->using_rx_dma = true; 1154 1155 skip_rx: 1156 /* Turn on DMA error (RX/TX will be enabled on demand) */ 1157 uap->dmacr |= UART011_DMAONERR; 1158 pl011_write(uap->dmacr, uap, REG_DMACR); 1159 1160 /* 1161 * ST Micro variants has some specific dma burst threshold 1162 * compensation. Set this to 16 bytes, so burst will only 1163 * be issued above/below 16 bytes. 1164 */ 1165 if (uap->vendor->dma_threshold) 1166 pl011_write(ST_UART011_DMAWM_RX_16 | ST_UART011_DMAWM_TX_16, 1167 uap, REG_ST_DMAWM); 1168 1169 if (uap->using_rx_dma) { 1170 if (pl011_dma_rx_trigger_dma(uap)) 1171 dev_dbg(uap->port.dev, "could not trigger initial " 1172 "RX DMA job, fall back to interrupt mode\n"); 1173 if (uap->dmarx.poll_rate) { 1174 timer_setup(&uap->dmarx.timer, pl011_dma_rx_poll, 0); 1175 mod_timer(&uap->dmarx.timer, 1176 jiffies + 1177 msecs_to_jiffies(uap->dmarx.poll_rate)); 1178 uap->dmarx.last_residue = PL011_DMA_BUFFER_SIZE; 1179 uap->dmarx.last_jiffies = jiffies; 1180 } 1181 } 1182 } 1183 1184 static void pl011_dma_shutdown(struct uart_amba_port *uap) 1185 { 1186 if (!(uap->using_tx_dma || uap->using_rx_dma)) 1187 return; 1188 1189 /* Disable RX and TX DMA */ 1190 while (pl011_read(uap, REG_FR) & uap->vendor->fr_busy) 1191 cpu_relax(); 1192 1193 spin_lock_irq(&uap->port.lock); 1194 uap->dmacr &= ~(UART011_DMAONERR | UART011_RXDMAE | UART011_TXDMAE); 1195 pl011_write(uap->dmacr, uap, REG_DMACR); 1196 spin_unlock_irq(&uap->port.lock); 1197 1198 if (uap->using_tx_dma) { 1199 /* In theory, this should already be done by pl011_dma_flush_buffer */ 1200 dmaengine_terminate_all(uap->dmatx.chan); 1201 if (uap->dmatx.queued) { 1202 dma_unmap_sg(uap->dmatx.chan->device->dev, &uap->dmatx.sg, 1, 1203 DMA_TO_DEVICE); 1204 uap->dmatx.queued = false; 1205 } 1206 1207 kfree(uap->dmatx.buf); 1208 uap->using_tx_dma = false; 1209 } 1210 1211 if (uap->using_rx_dma) { 1212 dmaengine_terminate_all(uap->dmarx.chan); 1213 /* Clean up the RX DMA */ 1214 pl011_sgbuf_free(uap->dmarx.chan, &uap->dmarx.sgbuf_a, DMA_FROM_DEVICE); 1215 pl011_sgbuf_free(uap->dmarx.chan, &uap->dmarx.sgbuf_b, DMA_FROM_DEVICE); 1216 if (uap->dmarx.poll_rate) 1217 del_timer_sync(&uap->dmarx.timer); 1218 uap->using_rx_dma = false; 1219 } 1220 } 1221 1222 static inline bool pl011_dma_rx_available(struct uart_amba_port *uap) 1223 { 1224 return uap->using_rx_dma; 1225 } 1226 1227 static inline bool pl011_dma_rx_running(struct uart_amba_port *uap) 1228 { 1229 return uap->using_rx_dma && uap->dmarx.running; 1230 } 1231 1232 #else 1233 /* Blank functions if the DMA engine is not available */ 1234 static inline void pl011_dma_remove(struct uart_amba_port *uap) 1235 { 1236 } 1237 1238 static inline void pl011_dma_startup(struct uart_amba_port *uap) 1239 { 1240 } 1241 1242 static inline void pl011_dma_shutdown(struct uart_amba_port *uap) 1243 { 1244 } 1245 1246 static inline bool pl011_dma_tx_irq(struct uart_amba_port *uap) 1247 { 1248 return false; 1249 } 1250 1251 static inline void pl011_dma_tx_stop(struct uart_amba_port *uap) 1252 { 1253 } 1254 1255 static inline bool pl011_dma_tx_start(struct uart_amba_port *uap) 1256 { 1257 return false; 1258 } 1259 1260 static inline void pl011_dma_rx_irq(struct uart_amba_port *uap) 1261 { 1262 } 1263 1264 static inline void pl011_dma_rx_stop(struct uart_amba_port *uap) 1265 { 1266 } 1267 1268 static inline int pl011_dma_rx_trigger_dma(struct uart_amba_port *uap) 1269 { 1270 return -EIO; 1271 } 1272 1273 static inline bool pl011_dma_rx_available(struct uart_amba_port *uap) 1274 { 1275 return false; 1276 } 1277 1278 static inline bool pl011_dma_rx_running(struct uart_amba_port *uap) 1279 { 1280 return false; 1281 } 1282 1283 #define pl011_dma_flush_buffer NULL 1284 #endif 1285 1286 static void pl011_rs485_tx_stop(struct uart_amba_port *uap) 1287 { 1288 /* 1289 * To be on the safe side only time out after twice as many iterations 1290 * as fifo size. 1291 */ 1292 const int MAX_TX_DRAIN_ITERS = uap->port.fifosize * 2; 1293 struct uart_port *port = &uap->port; 1294 int i = 0; 1295 u32 cr; 1296 1297 /* Wait until hardware tx queue is empty */ 1298 while (!pl011_tx_empty(port)) { 1299 if (i > MAX_TX_DRAIN_ITERS) { 1300 dev_warn(port->dev, 1301 "timeout while draining hardware tx queue\n"); 1302 break; 1303 } 1304 1305 udelay(uap->rs485_tx_drain_interval); 1306 i++; 1307 } 1308 1309 if (port->rs485.delay_rts_after_send) 1310 mdelay(port->rs485.delay_rts_after_send); 1311 1312 cr = pl011_read(uap, REG_CR); 1313 1314 if (port->rs485.flags & SER_RS485_RTS_AFTER_SEND) 1315 cr &= ~UART011_CR_RTS; 1316 else 1317 cr |= UART011_CR_RTS; 1318 1319 /* Disable the transmitter and reenable the transceiver */ 1320 cr &= ~UART011_CR_TXE; 1321 cr |= UART011_CR_RXE; 1322 pl011_write(cr, uap, REG_CR); 1323 1324 uap->rs485_tx_started = false; 1325 } 1326 1327 static void pl011_stop_tx(struct uart_port *port) 1328 { 1329 struct uart_amba_port *uap = 1330 container_of(port, struct uart_amba_port, port); 1331 1332 uap->im &= ~UART011_TXIM; 1333 pl011_write(uap->im, uap, REG_IMSC); 1334 pl011_dma_tx_stop(uap); 1335 1336 if ((port->rs485.flags & SER_RS485_ENABLED) && uap->rs485_tx_started) 1337 pl011_rs485_tx_stop(uap); 1338 } 1339 1340 static bool pl011_tx_chars(struct uart_amba_port *uap, bool from_irq); 1341 1342 /* Start TX with programmed I/O only (no DMA) */ 1343 static void pl011_start_tx_pio(struct uart_amba_port *uap) 1344 { 1345 if (pl011_tx_chars(uap, false)) { 1346 uap->im |= UART011_TXIM; 1347 pl011_write(uap->im, uap, REG_IMSC); 1348 } 1349 } 1350 1351 static void pl011_start_tx(struct uart_port *port) 1352 { 1353 struct uart_amba_port *uap = 1354 container_of(port, struct uart_amba_port, port); 1355 1356 if (!pl011_dma_tx_start(uap)) 1357 pl011_start_tx_pio(uap); 1358 } 1359 1360 static void pl011_stop_rx(struct uart_port *port) 1361 { 1362 struct uart_amba_port *uap = 1363 container_of(port, struct uart_amba_port, port); 1364 1365 uap->im &= ~(UART011_RXIM|UART011_RTIM|UART011_FEIM| 1366 UART011_PEIM|UART011_BEIM|UART011_OEIM); 1367 pl011_write(uap->im, uap, REG_IMSC); 1368 1369 pl011_dma_rx_stop(uap); 1370 } 1371 1372 static void pl011_throttle_rx(struct uart_port *port) 1373 { 1374 unsigned long flags; 1375 1376 spin_lock_irqsave(&port->lock, flags); 1377 pl011_stop_rx(port); 1378 spin_unlock_irqrestore(&port->lock, flags); 1379 } 1380 1381 static void pl011_enable_ms(struct uart_port *port) 1382 { 1383 struct uart_amba_port *uap = 1384 container_of(port, struct uart_amba_port, port); 1385 1386 uap->im |= UART011_RIMIM|UART011_CTSMIM|UART011_DCDMIM|UART011_DSRMIM; 1387 pl011_write(uap->im, uap, REG_IMSC); 1388 } 1389 1390 static void pl011_rx_chars(struct uart_amba_port *uap) 1391 __releases(&uap->port.lock) 1392 __acquires(&uap->port.lock) 1393 { 1394 pl011_fifo_to_tty(uap); 1395 1396 spin_unlock(&uap->port.lock); 1397 tty_flip_buffer_push(&uap->port.state->port); 1398 /* 1399 * If we were temporarily out of DMA mode for a while, 1400 * attempt to switch back to DMA mode again. 1401 */ 1402 if (pl011_dma_rx_available(uap)) { 1403 if (pl011_dma_rx_trigger_dma(uap)) { 1404 dev_dbg(uap->port.dev, "could not trigger RX DMA job " 1405 "fall back to interrupt mode again\n"); 1406 uap->im |= UART011_RXIM; 1407 pl011_write(uap->im, uap, REG_IMSC); 1408 } else { 1409 #ifdef CONFIG_DMA_ENGINE 1410 /* Start Rx DMA poll */ 1411 if (uap->dmarx.poll_rate) { 1412 uap->dmarx.last_jiffies = jiffies; 1413 uap->dmarx.last_residue = PL011_DMA_BUFFER_SIZE; 1414 mod_timer(&uap->dmarx.timer, 1415 jiffies + 1416 msecs_to_jiffies(uap->dmarx.poll_rate)); 1417 } 1418 #endif 1419 } 1420 } 1421 spin_lock(&uap->port.lock); 1422 } 1423 1424 static bool pl011_tx_char(struct uart_amba_port *uap, unsigned char c, 1425 bool from_irq) 1426 { 1427 if (unlikely(!from_irq) && 1428 pl011_read(uap, REG_FR) & UART01x_FR_TXFF) 1429 return false; /* unable to transmit character */ 1430 1431 pl011_write(c, uap, REG_DR); 1432 uap->port.icount.tx++; 1433 1434 return true; 1435 } 1436 1437 static void pl011_rs485_tx_start(struct uart_amba_port *uap) 1438 { 1439 struct uart_port *port = &uap->port; 1440 u32 cr; 1441 1442 /* Enable transmitter */ 1443 cr = pl011_read(uap, REG_CR); 1444 cr |= UART011_CR_TXE; 1445 1446 /* Disable receiver if half-duplex */ 1447 if (!(port->rs485.flags & SER_RS485_RX_DURING_TX)) 1448 cr &= ~UART011_CR_RXE; 1449 1450 if (port->rs485.flags & SER_RS485_RTS_ON_SEND) 1451 cr &= ~UART011_CR_RTS; 1452 else 1453 cr |= UART011_CR_RTS; 1454 1455 pl011_write(cr, uap, REG_CR); 1456 1457 if (port->rs485.delay_rts_before_send) 1458 mdelay(port->rs485.delay_rts_before_send); 1459 1460 uap->rs485_tx_started = true; 1461 } 1462 1463 /* Returns true if tx interrupts have to be (kept) enabled */ 1464 static bool pl011_tx_chars(struct uart_amba_port *uap, bool from_irq) 1465 { 1466 struct circ_buf *xmit = &uap->port.state->xmit; 1467 int count = uap->fifosize >> 1; 1468 1469 if ((uap->port.rs485.flags & SER_RS485_ENABLED) && 1470 !uap->rs485_tx_started) 1471 pl011_rs485_tx_start(uap); 1472 1473 if (uap->port.x_char) { 1474 if (!pl011_tx_char(uap, uap->port.x_char, from_irq)) 1475 return true; 1476 uap->port.x_char = 0; 1477 --count; 1478 } 1479 if (uart_circ_empty(xmit) || uart_tx_stopped(&uap->port)) { 1480 pl011_stop_tx(&uap->port); 1481 return false; 1482 } 1483 1484 /* If we are using DMA mode, try to send some characters. */ 1485 if (pl011_dma_tx_irq(uap)) 1486 return true; 1487 1488 do { 1489 if (likely(from_irq) && count-- == 0) 1490 break; 1491 1492 if (!pl011_tx_char(uap, xmit->buf[xmit->tail], from_irq)) 1493 break; 1494 1495 xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1); 1496 } while (!uart_circ_empty(xmit)); 1497 1498 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) 1499 uart_write_wakeup(&uap->port); 1500 1501 if (uart_circ_empty(xmit)) { 1502 pl011_stop_tx(&uap->port); 1503 return false; 1504 } 1505 return true; 1506 } 1507 1508 static void pl011_modem_status(struct uart_amba_port *uap) 1509 { 1510 unsigned int status, delta; 1511 1512 status = pl011_read(uap, REG_FR) & UART01x_FR_MODEM_ANY; 1513 1514 delta = status ^ uap->old_status; 1515 uap->old_status = status; 1516 1517 if (!delta) 1518 return; 1519 1520 if (delta & UART01x_FR_DCD) 1521 uart_handle_dcd_change(&uap->port, status & UART01x_FR_DCD); 1522 1523 if (delta & uap->vendor->fr_dsr) 1524 uap->port.icount.dsr++; 1525 1526 if (delta & uap->vendor->fr_cts) 1527 uart_handle_cts_change(&uap->port, 1528 status & uap->vendor->fr_cts); 1529 1530 wake_up_interruptible(&uap->port.state->port.delta_msr_wait); 1531 } 1532 1533 static void check_apply_cts_event_workaround(struct uart_amba_port *uap) 1534 { 1535 if (!uap->vendor->cts_event_workaround) 1536 return; 1537 1538 /* workaround to make sure that all bits are unlocked.. */ 1539 pl011_write(0x00, uap, REG_ICR); 1540 1541 /* 1542 * WA: introduce 26ns(1 uart clk) delay before W1C; 1543 * single apb access will incur 2 pclk(133.12Mhz) delay, 1544 * so add 2 dummy reads 1545 */ 1546 pl011_read(uap, REG_ICR); 1547 pl011_read(uap, REG_ICR); 1548 } 1549 1550 static irqreturn_t pl011_int(int irq, void *dev_id) 1551 { 1552 struct uart_amba_port *uap = dev_id; 1553 unsigned long flags; 1554 unsigned int status, pass_counter = AMBA_ISR_PASS_LIMIT; 1555 int handled = 0; 1556 1557 spin_lock_irqsave(&uap->port.lock, flags); 1558 status = pl011_read(uap, REG_RIS) & uap->im; 1559 if (status) { 1560 do { 1561 check_apply_cts_event_workaround(uap); 1562 1563 pl011_write(status & ~(UART011_TXIS|UART011_RTIS| 1564 UART011_RXIS), 1565 uap, REG_ICR); 1566 1567 if (status & (UART011_RTIS|UART011_RXIS)) { 1568 if (pl011_dma_rx_running(uap)) 1569 pl011_dma_rx_irq(uap); 1570 else 1571 pl011_rx_chars(uap); 1572 } 1573 if (status & (UART011_DSRMIS|UART011_DCDMIS| 1574 UART011_CTSMIS|UART011_RIMIS)) 1575 pl011_modem_status(uap); 1576 if (status & UART011_TXIS) 1577 pl011_tx_chars(uap, true); 1578 1579 if (pass_counter-- == 0) 1580 break; 1581 1582 status = pl011_read(uap, REG_RIS) & uap->im; 1583 } while (status != 0); 1584 handled = 1; 1585 } 1586 1587 spin_unlock_irqrestore(&uap->port.lock, flags); 1588 1589 return IRQ_RETVAL(handled); 1590 } 1591 1592 static unsigned int pl011_tx_empty(struct uart_port *port) 1593 { 1594 struct uart_amba_port *uap = 1595 container_of(port, struct uart_amba_port, port); 1596 1597 /* Allow feature register bits to be inverted to work around errata */ 1598 unsigned int status = pl011_read(uap, REG_FR) ^ uap->vendor->inv_fr; 1599 1600 return status & (uap->vendor->fr_busy | UART01x_FR_TXFF) ? 1601 0 : TIOCSER_TEMT; 1602 } 1603 1604 static unsigned int pl011_get_mctrl(struct uart_port *port) 1605 { 1606 struct uart_amba_port *uap = 1607 container_of(port, struct uart_amba_port, port); 1608 unsigned int result = 0; 1609 unsigned int status = pl011_read(uap, REG_FR); 1610 1611 #define TIOCMBIT(uartbit, tiocmbit) \ 1612 if (status & uartbit) \ 1613 result |= tiocmbit 1614 1615 TIOCMBIT(UART01x_FR_DCD, TIOCM_CAR); 1616 TIOCMBIT(uap->vendor->fr_dsr, TIOCM_DSR); 1617 TIOCMBIT(uap->vendor->fr_cts, TIOCM_CTS); 1618 TIOCMBIT(uap->vendor->fr_ri, TIOCM_RNG); 1619 #undef TIOCMBIT 1620 return result; 1621 } 1622 1623 static void pl011_set_mctrl(struct uart_port *port, unsigned int mctrl) 1624 { 1625 struct uart_amba_port *uap = 1626 container_of(port, struct uart_amba_port, port); 1627 unsigned int cr; 1628 1629 cr = pl011_read(uap, REG_CR); 1630 1631 #define TIOCMBIT(tiocmbit, uartbit) \ 1632 if (mctrl & tiocmbit) \ 1633 cr |= uartbit; \ 1634 else \ 1635 cr &= ~uartbit 1636 1637 TIOCMBIT(TIOCM_RTS, UART011_CR_RTS); 1638 TIOCMBIT(TIOCM_DTR, UART011_CR_DTR); 1639 TIOCMBIT(TIOCM_OUT1, UART011_CR_OUT1); 1640 TIOCMBIT(TIOCM_OUT2, UART011_CR_OUT2); 1641 TIOCMBIT(TIOCM_LOOP, UART011_CR_LBE); 1642 1643 if (port->status & UPSTAT_AUTORTS) { 1644 /* We need to disable auto-RTS if we want to turn RTS off */ 1645 TIOCMBIT(TIOCM_RTS, UART011_CR_RTSEN); 1646 } 1647 #undef TIOCMBIT 1648 1649 pl011_write(cr, uap, REG_CR); 1650 } 1651 1652 static void pl011_break_ctl(struct uart_port *port, int break_state) 1653 { 1654 struct uart_amba_port *uap = 1655 container_of(port, struct uart_amba_port, port); 1656 unsigned long flags; 1657 unsigned int lcr_h; 1658 1659 spin_lock_irqsave(&uap->port.lock, flags); 1660 lcr_h = pl011_read(uap, REG_LCRH_TX); 1661 if (break_state == -1) 1662 lcr_h |= UART01x_LCRH_BRK; 1663 else 1664 lcr_h &= ~UART01x_LCRH_BRK; 1665 pl011_write(lcr_h, uap, REG_LCRH_TX); 1666 spin_unlock_irqrestore(&uap->port.lock, flags); 1667 } 1668 1669 #ifdef CONFIG_CONSOLE_POLL 1670 1671 static void pl011_quiesce_irqs(struct uart_port *port) 1672 { 1673 struct uart_amba_port *uap = 1674 container_of(port, struct uart_amba_port, port); 1675 1676 pl011_write(pl011_read(uap, REG_MIS), uap, REG_ICR); 1677 /* 1678 * There is no way to clear TXIM as this is "ready to transmit IRQ", so 1679 * we simply mask it. start_tx() will unmask it. 1680 * 1681 * Note we can race with start_tx(), and if the race happens, the 1682 * polling user might get another interrupt just after we clear it. 1683 * But it should be OK and can happen even w/o the race, e.g. 1684 * controller immediately got some new data and raised the IRQ. 1685 * 1686 * And whoever uses polling routines assumes that it manages the device 1687 * (including tx queue), so we're also fine with start_tx()'s caller 1688 * side. 1689 */ 1690 pl011_write(pl011_read(uap, REG_IMSC) & ~UART011_TXIM, uap, 1691 REG_IMSC); 1692 } 1693 1694 static int pl011_get_poll_char(struct uart_port *port) 1695 { 1696 struct uart_amba_port *uap = 1697 container_of(port, struct uart_amba_port, port); 1698 unsigned int status; 1699 1700 /* 1701 * The caller might need IRQs lowered, e.g. if used with KDB NMI 1702 * debugger. 1703 */ 1704 pl011_quiesce_irqs(port); 1705 1706 status = pl011_read(uap, REG_FR); 1707 if (status & UART01x_FR_RXFE) 1708 return NO_POLL_CHAR; 1709 1710 return pl011_read(uap, REG_DR); 1711 } 1712 1713 static void pl011_put_poll_char(struct uart_port *port, 1714 unsigned char ch) 1715 { 1716 struct uart_amba_port *uap = 1717 container_of(port, struct uart_amba_port, port); 1718 1719 while (pl011_read(uap, REG_FR) & UART01x_FR_TXFF) 1720 cpu_relax(); 1721 1722 pl011_write(ch, uap, REG_DR); 1723 } 1724 1725 #endif /* CONFIG_CONSOLE_POLL */ 1726 1727 static int pl011_hwinit(struct uart_port *port) 1728 { 1729 struct uart_amba_port *uap = 1730 container_of(port, struct uart_amba_port, port); 1731 int retval; 1732 1733 /* Optionaly enable pins to be muxed in and configured */ 1734 pinctrl_pm_select_default_state(port->dev); 1735 1736 /* 1737 * Try to enable the clock producer. 1738 */ 1739 retval = clk_prepare_enable(uap->clk); 1740 if (retval) 1741 return retval; 1742 1743 uap->port.uartclk = clk_get_rate(uap->clk); 1744 1745 /* Clear pending error and receive interrupts */ 1746 pl011_write(UART011_OEIS | UART011_BEIS | UART011_PEIS | 1747 UART011_FEIS | UART011_RTIS | UART011_RXIS, 1748 uap, REG_ICR); 1749 1750 /* 1751 * Save interrupts enable mask, and enable RX interrupts in case if 1752 * the interrupt is used for NMI entry. 1753 */ 1754 uap->im = pl011_read(uap, REG_IMSC); 1755 pl011_write(UART011_RTIM | UART011_RXIM, uap, REG_IMSC); 1756 1757 if (dev_get_platdata(uap->port.dev)) { 1758 struct amba_pl011_data *plat; 1759 1760 plat = dev_get_platdata(uap->port.dev); 1761 if (plat->init) 1762 plat->init(); 1763 } 1764 return 0; 1765 } 1766 1767 static bool pl011_split_lcrh(const struct uart_amba_port *uap) 1768 { 1769 return pl011_reg_to_offset(uap, REG_LCRH_RX) != 1770 pl011_reg_to_offset(uap, REG_LCRH_TX); 1771 } 1772 1773 static void pl011_write_lcr_h(struct uart_amba_port *uap, unsigned int lcr_h) 1774 { 1775 pl011_write(lcr_h, uap, REG_LCRH_RX); 1776 if (pl011_split_lcrh(uap)) { 1777 int i; 1778 /* 1779 * Wait 10 PCLKs before writing LCRH_TX register, 1780 * to get this delay write read only register 10 times 1781 */ 1782 for (i = 0; i < 10; ++i) 1783 pl011_write(0xff, uap, REG_MIS); 1784 pl011_write(lcr_h, uap, REG_LCRH_TX); 1785 } 1786 } 1787 1788 static int pl011_allocate_irq(struct uart_amba_port *uap) 1789 { 1790 pl011_write(uap->im, uap, REG_IMSC); 1791 1792 return request_irq(uap->port.irq, pl011_int, IRQF_SHARED, "uart-pl011", uap); 1793 } 1794 1795 /* 1796 * Enable interrupts, only timeouts when using DMA 1797 * if initial RX DMA job failed, start in interrupt mode 1798 * as well. 1799 */ 1800 static void pl011_enable_interrupts(struct uart_amba_port *uap) 1801 { 1802 unsigned long flags; 1803 unsigned int i; 1804 1805 spin_lock_irqsave(&uap->port.lock, flags); 1806 1807 /* Clear out any spuriously appearing RX interrupts */ 1808 pl011_write(UART011_RTIS | UART011_RXIS, uap, REG_ICR); 1809 1810 /* 1811 * RXIS is asserted only when the RX FIFO transitions from below 1812 * to above the trigger threshold. If the RX FIFO is already 1813 * full to the threshold this can't happen and RXIS will now be 1814 * stuck off. Drain the RX FIFO explicitly to fix this: 1815 */ 1816 for (i = 0; i < uap->fifosize * 2; ++i) { 1817 if (pl011_read(uap, REG_FR) & UART01x_FR_RXFE) 1818 break; 1819 1820 pl011_read(uap, REG_DR); 1821 } 1822 1823 uap->im = UART011_RTIM; 1824 if (!pl011_dma_rx_running(uap)) 1825 uap->im |= UART011_RXIM; 1826 pl011_write(uap->im, uap, REG_IMSC); 1827 spin_unlock_irqrestore(&uap->port.lock, flags); 1828 } 1829 1830 static void pl011_unthrottle_rx(struct uart_port *port) 1831 { 1832 struct uart_amba_port *uap = container_of(port, struct uart_amba_port, port); 1833 unsigned long flags; 1834 1835 spin_lock_irqsave(&uap->port.lock, flags); 1836 1837 uap->im = UART011_RTIM; 1838 if (!pl011_dma_rx_running(uap)) 1839 uap->im |= UART011_RXIM; 1840 1841 pl011_write(uap->im, uap, REG_IMSC); 1842 1843 spin_unlock_irqrestore(&uap->port.lock, flags); 1844 } 1845 1846 static int pl011_startup(struct uart_port *port) 1847 { 1848 struct uart_amba_port *uap = 1849 container_of(port, struct uart_amba_port, port); 1850 unsigned int cr; 1851 int retval; 1852 1853 retval = pl011_hwinit(port); 1854 if (retval) 1855 goto clk_dis; 1856 1857 retval = pl011_allocate_irq(uap); 1858 if (retval) 1859 goto clk_dis; 1860 1861 pl011_write(uap->vendor->ifls, uap, REG_IFLS); 1862 1863 spin_lock_irq(&uap->port.lock); 1864 1865 cr = pl011_read(uap, REG_CR); 1866 cr &= UART011_CR_RTS | UART011_CR_DTR; 1867 cr |= UART01x_CR_UARTEN | UART011_CR_RXE; 1868 1869 if (!(port->rs485.flags & SER_RS485_ENABLED)) 1870 cr |= UART011_CR_TXE; 1871 1872 pl011_write(cr, uap, REG_CR); 1873 1874 spin_unlock_irq(&uap->port.lock); 1875 1876 /* 1877 * initialise the old status of the modem signals 1878 */ 1879 uap->old_status = pl011_read(uap, REG_FR) & UART01x_FR_MODEM_ANY; 1880 1881 /* Startup DMA */ 1882 pl011_dma_startup(uap); 1883 1884 pl011_enable_interrupts(uap); 1885 1886 return 0; 1887 1888 clk_dis: 1889 clk_disable_unprepare(uap->clk); 1890 return retval; 1891 } 1892 1893 static int sbsa_uart_startup(struct uart_port *port) 1894 { 1895 struct uart_amba_port *uap = 1896 container_of(port, struct uart_amba_port, port); 1897 int retval; 1898 1899 retval = pl011_hwinit(port); 1900 if (retval) 1901 return retval; 1902 1903 retval = pl011_allocate_irq(uap); 1904 if (retval) 1905 return retval; 1906 1907 /* The SBSA UART does not support any modem status lines. */ 1908 uap->old_status = 0; 1909 1910 pl011_enable_interrupts(uap); 1911 1912 return 0; 1913 } 1914 1915 static void pl011_shutdown_channel(struct uart_amba_port *uap, 1916 unsigned int lcrh) 1917 { 1918 unsigned long val; 1919 1920 val = pl011_read(uap, lcrh); 1921 val &= ~(UART01x_LCRH_BRK | UART01x_LCRH_FEN); 1922 pl011_write(val, uap, lcrh); 1923 } 1924 1925 /* 1926 * disable the port. It should not disable RTS and DTR. 1927 * Also RTS and DTR state should be preserved to restore 1928 * it during startup(). 1929 */ 1930 static void pl011_disable_uart(struct uart_amba_port *uap) 1931 { 1932 unsigned int cr; 1933 1934 uap->port.status &= ~(UPSTAT_AUTOCTS | UPSTAT_AUTORTS); 1935 spin_lock_irq(&uap->port.lock); 1936 cr = pl011_read(uap, REG_CR); 1937 cr &= UART011_CR_RTS | UART011_CR_DTR; 1938 cr |= UART01x_CR_UARTEN | UART011_CR_TXE; 1939 pl011_write(cr, uap, REG_CR); 1940 spin_unlock_irq(&uap->port.lock); 1941 1942 /* 1943 * disable break condition and fifos 1944 */ 1945 pl011_shutdown_channel(uap, REG_LCRH_RX); 1946 if (pl011_split_lcrh(uap)) 1947 pl011_shutdown_channel(uap, REG_LCRH_TX); 1948 } 1949 1950 static void pl011_disable_interrupts(struct uart_amba_port *uap) 1951 { 1952 spin_lock_irq(&uap->port.lock); 1953 1954 /* mask all interrupts and clear all pending ones */ 1955 uap->im = 0; 1956 pl011_write(uap->im, uap, REG_IMSC); 1957 pl011_write(0xffff, uap, REG_ICR); 1958 1959 spin_unlock_irq(&uap->port.lock); 1960 } 1961 1962 static void pl011_shutdown(struct uart_port *port) 1963 { 1964 struct uart_amba_port *uap = 1965 container_of(port, struct uart_amba_port, port); 1966 1967 pl011_disable_interrupts(uap); 1968 1969 pl011_dma_shutdown(uap); 1970 1971 if ((port->rs485.flags & SER_RS485_ENABLED) && uap->rs485_tx_started) 1972 pl011_rs485_tx_stop(uap); 1973 1974 free_irq(uap->port.irq, uap); 1975 1976 pl011_disable_uart(uap); 1977 1978 /* 1979 * Shut down the clock producer 1980 */ 1981 clk_disable_unprepare(uap->clk); 1982 /* Optionally let pins go into sleep states */ 1983 pinctrl_pm_select_sleep_state(port->dev); 1984 1985 if (dev_get_platdata(uap->port.dev)) { 1986 struct amba_pl011_data *plat; 1987 1988 plat = dev_get_platdata(uap->port.dev); 1989 if (plat->exit) 1990 plat->exit(); 1991 } 1992 1993 if (uap->port.ops->flush_buffer) 1994 uap->port.ops->flush_buffer(port); 1995 } 1996 1997 static void sbsa_uart_shutdown(struct uart_port *port) 1998 { 1999 struct uart_amba_port *uap = 2000 container_of(port, struct uart_amba_port, port); 2001 2002 pl011_disable_interrupts(uap); 2003 2004 free_irq(uap->port.irq, uap); 2005 2006 if (uap->port.ops->flush_buffer) 2007 uap->port.ops->flush_buffer(port); 2008 } 2009 2010 static void 2011 pl011_setup_status_masks(struct uart_port *port, struct ktermios *termios) 2012 { 2013 port->read_status_mask = UART011_DR_OE | 255; 2014 if (termios->c_iflag & INPCK) 2015 port->read_status_mask |= UART011_DR_FE | UART011_DR_PE; 2016 if (termios->c_iflag & (IGNBRK | BRKINT | PARMRK)) 2017 port->read_status_mask |= UART011_DR_BE; 2018 2019 /* 2020 * Characters to ignore 2021 */ 2022 port->ignore_status_mask = 0; 2023 if (termios->c_iflag & IGNPAR) 2024 port->ignore_status_mask |= UART011_DR_FE | UART011_DR_PE; 2025 if (termios->c_iflag & IGNBRK) { 2026 port->ignore_status_mask |= UART011_DR_BE; 2027 /* 2028 * If we're ignoring parity and break indicators, 2029 * ignore overruns too (for real raw support). 2030 */ 2031 if (termios->c_iflag & IGNPAR) 2032 port->ignore_status_mask |= UART011_DR_OE; 2033 } 2034 2035 /* 2036 * Ignore all characters if CREAD is not set. 2037 */ 2038 if ((termios->c_cflag & CREAD) == 0) 2039 port->ignore_status_mask |= UART_DUMMY_DR_RX; 2040 } 2041 2042 static void 2043 pl011_set_termios(struct uart_port *port, struct ktermios *termios, 2044 const struct ktermios *old) 2045 { 2046 struct uart_amba_port *uap = 2047 container_of(port, struct uart_amba_port, port); 2048 unsigned int lcr_h, old_cr; 2049 unsigned long flags; 2050 unsigned int baud, quot, clkdiv; 2051 unsigned int bits; 2052 2053 if (uap->vendor->oversampling) 2054 clkdiv = 8; 2055 else 2056 clkdiv = 16; 2057 2058 /* 2059 * Ask the core to calculate the divisor for us. 2060 */ 2061 baud = uart_get_baud_rate(port, termios, old, 0, 2062 port->uartclk / clkdiv); 2063 #ifdef CONFIG_DMA_ENGINE 2064 /* 2065 * Adjust RX DMA polling rate with baud rate if not specified. 2066 */ 2067 if (uap->dmarx.auto_poll_rate) 2068 uap->dmarx.poll_rate = DIV_ROUND_UP(10000000, baud); 2069 #endif 2070 2071 if (baud > port->uartclk/16) 2072 quot = DIV_ROUND_CLOSEST(port->uartclk * 8, baud); 2073 else 2074 quot = DIV_ROUND_CLOSEST(port->uartclk * 4, baud); 2075 2076 switch (termios->c_cflag & CSIZE) { 2077 case CS5: 2078 lcr_h = UART01x_LCRH_WLEN_5; 2079 break; 2080 case CS6: 2081 lcr_h = UART01x_LCRH_WLEN_6; 2082 break; 2083 case CS7: 2084 lcr_h = UART01x_LCRH_WLEN_7; 2085 break; 2086 default: // CS8 2087 lcr_h = UART01x_LCRH_WLEN_8; 2088 break; 2089 } 2090 if (termios->c_cflag & CSTOPB) 2091 lcr_h |= UART01x_LCRH_STP2; 2092 if (termios->c_cflag & PARENB) { 2093 lcr_h |= UART01x_LCRH_PEN; 2094 if (!(termios->c_cflag & PARODD)) 2095 lcr_h |= UART01x_LCRH_EPS; 2096 if (termios->c_cflag & CMSPAR) 2097 lcr_h |= UART011_LCRH_SPS; 2098 } 2099 if (uap->fifosize > 1) 2100 lcr_h |= UART01x_LCRH_FEN; 2101 2102 bits = tty_get_frame_size(termios->c_cflag); 2103 2104 spin_lock_irqsave(&port->lock, flags); 2105 2106 /* 2107 * Update the per-port timeout. 2108 */ 2109 uart_update_timeout(port, termios->c_cflag, baud); 2110 2111 /* 2112 * Calculate the approximated time it takes to transmit one character 2113 * with the given baud rate. We use this as the poll interval when we 2114 * wait for the tx queue to empty. 2115 */ 2116 uap->rs485_tx_drain_interval = DIV_ROUND_UP(bits * 1000 * 1000, baud); 2117 2118 pl011_setup_status_masks(port, termios); 2119 2120 if (UART_ENABLE_MS(port, termios->c_cflag)) 2121 pl011_enable_ms(port); 2122 2123 if (port->rs485.flags & SER_RS485_ENABLED) 2124 termios->c_cflag &= ~CRTSCTS; 2125 2126 old_cr = pl011_read(uap, REG_CR); 2127 2128 if (termios->c_cflag & CRTSCTS) { 2129 if (old_cr & UART011_CR_RTS) 2130 old_cr |= UART011_CR_RTSEN; 2131 2132 old_cr |= UART011_CR_CTSEN; 2133 port->status |= UPSTAT_AUTOCTS | UPSTAT_AUTORTS; 2134 } else { 2135 old_cr &= ~(UART011_CR_CTSEN | UART011_CR_RTSEN); 2136 port->status &= ~(UPSTAT_AUTOCTS | UPSTAT_AUTORTS); 2137 } 2138 2139 if (uap->vendor->oversampling) { 2140 if (baud > port->uartclk / 16) 2141 old_cr |= ST_UART011_CR_OVSFACT; 2142 else 2143 old_cr &= ~ST_UART011_CR_OVSFACT; 2144 } 2145 2146 /* 2147 * Workaround for the ST Micro oversampling variants to 2148 * increase the bitrate slightly, by lowering the divisor, 2149 * to avoid delayed sampling of start bit at high speeds, 2150 * else we see data corruption. 2151 */ 2152 if (uap->vendor->oversampling) { 2153 if ((baud >= 3000000) && (baud < 3250000) && (quot > 1)) 2154 quot -= 1; 2155 else if ((baud > 3250000) && (quot > 2)) 2156 quot -= 2; 2157 } 2158 /* Set baud rate */ 2159 pl011_write(quot & 0x3f, uap, REG_FBRD); 2160 pl011_write(quot >> 6, uap, REG_IBRD); 2161 2162 /* 2163 * ----------v----------v----------v----------v----- 2164 * NOTE: REG_LCRH_TX and REG_LCRH_RX MUST BE WRITTEN AFTER 2165 * REG_FBRD & REG_IBRD. 2166 * ----------^----------^----------^----------^----- 2167 */ 2168 pl011_write_lcr_h(uap, lcr_h); 2169 2170 /* 2171 * Receive was disabled by pl011_disable_uart during shutdown. 2172 * Need to reenable receive if you need to use a tty_driver 2173 * returns from tty_find_polling_driver() after a port shutdown. 2174 */ 2175 old_cr |= UART011_CR_RXE; 2176 pl011_write(old_cr, uap, REG_CR); 2177 2178 spin_unlock_irqrestore(&port->lock, flags); 2179 } 2180 2181 static void 2182 sbsa_uart_set_termios(struct uart_port *port, struct ktermios *termios, 2183 const struct ktermios *old) 2184 { 2185 struct uart_amba_port *uap = 2186 container_of(port, struct uart_amba_port, port); 2187 unsigned long flags; 2188 2189 tty_termios_encode_baud_rate(termios, uap->fixed_baud, uap->fixed_baud); 2190 2191 /* The SBSA UART only supports 8n1 without hardware flow control. */ 2192 termios->c_cflag &= ~(CSIZE | CSTOPB | PARENB | PARODD); 2193 termios->c_cflag &= ~(CMSPAR | CRTSCTS); 2194 termios->c_cflag |= CS8 | CLOCAL; 2195 2196 spin_lock_irqsave(&port->lock, flags); 2197 uart_update_timeout(port, CS8, uap->fixed_baud); 2198 pl011_setup_status_masks(port, termios); 2199 spin_unlock_irqrestore(&port->lock, flags); 2200 } 2201 2202 static const char *pl011_type(struct uart_port *port) 2203 { 2204 struct uart_amba_port *uap = 2205 container_of(port, struct uart_amba_port, port); 2206 return uap->port.type == PORT_AMBA ? uap->type : NULL; 2207 } 2208 2209 /* 2210 * Configure/autoconfigure the port. 2211 */ 2212 static void pl011_config_port(struct uart_port *port, int flags) 2213 { 2214 if (flags & UART_CONFIG_TYPE) 2215 port->type = PORT_AMBA; 2216 } 2217 2218 /* 2219 * verify the new serial_struct (for TIOCSSERIAL). 2220 */ 2221 static int pl011_verify_port(struct uart_port *port, struct serial_struct *ser) 2222 { 2223 int ret = 0; 2224 if (ser->type != PORT_UNKNOWN && ser->type != PORT_AMBA) 2225 ret = -EINVAL; 2226 if (ser->irq < 0 || ser->irq >= nr_irqs) 2227 ret = -EINVAL; 2228 if (ser->baud_base < 9600) 2229 ret = -EINVAL; 2230 if (port->mapbase != (unsigned long) ser->iomem_base) 2231 ret = -EINVAL; 2232 return ret; 2233 } 2234 2235 static int pl011_rs485_config(struct uart_port *port, struct ktermios *termios, 2236 struct serial_rs485 *rs485) 2237 { 2238 struct uart_amba_port *uap = 2239 container_of(port, struct uart_amba_port, port); 2240 2241 if (port->rs485.flags & SER_RS485_ENABLED) 2242 pl011_rs485_tx_stop(uap); 2243 2244 /* Make sure auto RTS is disabled */ 2245 if (rs485->flags & SER_RS485_ENABLED) { 2246 u32 cr = pl011_read(uap, REG_CR); 2247 2248 cr &= ~UART011_CR_RTSEN; 2249 pl011_write(cr, uap, REG_CR); 2250 port->status &= ~UPSTAT_AUTORTS; 2251 } 2252 2253 return 0; 2254 } 2255 2256 static const struct uart_ops amba_pl011_pops = { 2257 .tx_empty = pl011_tx_empty, 2258 .set_mctrl = pl011_set_mctrl, 2259 .get_mctrl = pl011_get_mctrl, 2260 .stop_tx = pl011_stop_tx, 2261 .start_tx = pl011_start_tx, 2262 .stop_rx = pl011_stop_rx, 2263 .throttle = pl011_throttle_rx, 2264 .unthrottle = pl011_unthrottle_rx, 2265 .enable_ms = pl011_enable_ms, 2266 .break_ctl = pl011_break_ctl, 2267 .startup = pl011_startup, 2268 .shutdown = pl011_shutdown, 2269 .flush_buffer = pl011_dma_flush_buffer, 2270 .set_termios = pl011_set_termios, 2271 .type = pl011_type, 2272 .config_port = pl011_config_port, 2273 .verify_port = pl011_verify_port, 2274 #ifdef CONFIG_CONSOLE_POLL 2275 .poll_init = pl011_hwinit, 2276 .poll_get_char = pl011_get_poll_char, 2277 .poll_put_char = pl011_put_poll_char, 2278 #endif 2279 }; 2280 2281 static void sbsa_uart_set_mctrl(struct uart_port *port, unsigned int mctrl) 2282 { 2283 } 2284 2285 static unsigned int sbsa_uart_get_mctrl(struct uart_port *port) 2286 { 2287 return 0; 2288 } 2289 2290 static const struct uart_ops sbsa_uart_pops = { 2291 .tx_empty = pl011_tx_empty, 2292 .set_mctrl = sbsa_uart_set_mctrl, 2293 .get_mctrl = sbsa_uart_get_mctrl, 2294 .stop_tx = pl011_stop_tx, 2295 .start_tx = pl011_start_tx, 2296 .stop_rx = pl011_stop_rx, 2297 .startup = sbsa_uart_startup, 2298 .shutdown = sbsa_uart_shutdown, 2299 .set_termios = sbsa_uart_set_termios, 2300 .type = pl011_type, 2301 .config_port = pl011_config_port, 2302 .verify_port = pl011_verify_port, 2303 #ifdef CONFIG_CONSOLE_POLL 2304 .poll_init = pl011_hwinit, 2305 .poll_get_char = pl011_get_poll_char, 2306 .poll_put_char = pl011_put_poll_char, 2307 #endif 2308 }; 2309 2310 static struct uart_amba_port *amba_ports[UART_NR]; 2311 2312 #ifdef CONFIG_SERIAL_AMBA_PL011_CONSOLE 2313 2314 static void pl011_console_putchar(struct uart_port *port, unsigned char ch) 2315 { 2316 struct uart_amba_port *uap = 2317 container_of(port, struct uart_amba_port, port); 2318 2319 while (pl011_read(uap, REG_FR) & UART01x_FR_TXFF) 2320 cpu_relax(); 2321 pl011_write(ch, uap, REG_DR); 2322 } 2323 2324 static void 2325 pl011_console_write(struct console *co, const char *s, unsigned int count) 2326 { 2327 struct uart_amba_port *uap = amba_ports[co->index]; 2328 unsigned int old_cr = 0, new_cr; 2329 unsigned long flags; 2330 int locked = 1; 2331 2332 clk_enable(uap->clk); 2333 2334 local_irq_save(flags); 2335 if (uap->port.sysrq) 2336 locked = 0; 2337 else if (oops_in_progress) 2338 locked = spin_trylock(&uap->port.lock); 2339 else 2340 spin_lock(&uap->port.lock); 2341 2342 /* 2343 * First save the CR then disable the interrupts 2344 */ 2345 if (!uap->vendor->always_enabled) { 2346 old_cr = pl011_read(uap, REG_CR); 2347 new_cr = old_cr & ~UART011_CR_CTSEN; 2348 new_cr |= UART01x_CR_UARTEN | UART011_CR_TXE; 2349 pl011_write(new_cr, uap, REG_CR); 2350 } 2351 2352 uart_console_write(&uap->port, s, count, pl011_console_putchar); 2353 2354 /* 2355 * Finally, wait for transmitter to become empty and restore the 2356 * TCR. Allow feature register bits to be inverted to work around 2357 * errata. 2358 */ 2359 while ((pl011_read(uap, REG_FR) ^ uap->vendor->inv_fr) 2360 & uap->vendor->fr_busy) 2361 cpu_relax(); 2362 if (!uap->vendor->always_enabled) 2363 pl011_write(old_cr, uap, REG_CR); 2364 2365 if (locked) 2366 spin_unlock(&uap->port.lock); 2367 local_irq_restore(flags); 2368 2369 clk_disable(uap->clk); 2370 } 2371 2372 static void pl011_console_get_options(struct uart_amba_port *uap, int *baud, 2373 int *parity, int *bits) 2374 { 2375 if (pl011_read(uap, REG_CR) & UART01x_CR_UARTEN) { 2376 unsigned int lcr_h, ibrd, fbrd; 2377 2378 lcr_h = pl011_read(uap, REG_LCRH_TX); 2379 2380 *parity = 'n'; 2381 if (lcr_h & UART01x_LCRH_PEN) { 2382 if (lcr_h & UART01x_LCRH_EPS) 2383 *parity = 'e'; 2384 else 2385 *parity = 'o'; 2386 } 2387 2388 if ((lcr_h & 0x60) == UART01x_LCRH_WLEN_7) 2389 *bits = 7; 2390 else 2391 *bits = 8; 2392 2393 ibrd = pl011_read(uap, REG_IBRD); 2394 fbrd = pl011_read(uap, REG_FBRD); 2395 2396 *baud = uap->port.uartclk * 4 / (64 * ibrd + fbrd); 2397 2398 if (uap->vendor->oversampling) { 2399 if (pl011_read(uap, REG_CR) 2400 & ST_UART011_CR_OVSFACT) 2401 *baud *= 2; 2402 } 2403 } 2404 } 2405 2406 static int pl011_console_setup(struct console *co, char *options) 2407 { 2408 struct uart_amba_port *uap; 2409 int baud = 38400; 2410 int bits = 8; 2411 int parity = 'n'; 2412 int flow = 'n'; 2413 int ret; 2414 2415 /* 2416 * Check whether an invalid uart number has been specified, and 2417 * if so, search for the first available port that does have 2418 * console support. 2419 */ 2420 if (co->index >= UART_NR) 2421 co->index = 0; 2422 uap = amba_ports[co->index]; 2423 if (!uap) 2424 return -ENODEV; 2425 2426 /* Allow pins to be muxed in and configured */ 2427 pinctrl_pm_select_default_state(uap->port.dev); 2428 2429 ret = clk_prepare(uap->clk); 2430 if (ret) 2431 return ret; 2432 2433 if (dev_get_platdata(uap->port.dev)) { 2434 struct amba_pl011_data *plat; 2435 2436 plat = dev_get_platdata(uap->port.dev); 2437 if (plat->init) 2438 plat->init(); 2439 } 2440 2441 uap->port.uartclk = clk_get_rate(uap->clk); 2442 2443 if (uap->vendor->fixed_options) { 2444 baud = uap->fixed_baud; 2445 } else { 2446 if (options) 2447 uart_parse_options(options, 2448 &baud, &parity, &bits, &flow); 2449 else 2450 pl011_console_get_options(uap, &baud, &parity, &bits); 2451 } 2452 2453 return uart_set_options(&uap->port, co, baud, parity, bits, flow); 2454 } 2455 2456 /** 2457 * pl011_console_match - non-standard console matching 2458 * @co: registering console 2459 * @name: name from console command line 2460 * @idx: index from console command line 2461 * @options: ptr to option string from console command line 2462 * 2463 * Only attempts to match console command lines of the form: 2464 * console=pl011,mmio|mmio32,<addr>[,<options>] 2465 * console=pl011,0x<addr>[,<options>] 2466 * This form is used to register an initial earlycon boot console and 2467 * replace it with the amba_console at pl011 driver init. 2468 * 2469 * Performs console setup for a match (as required by interface) 2470 * If no <options> are specified, then assume the h/w is already setup. 2471 * 2472 * Returns 0 if console matches; otherwise non-zero to use default matching 2473 */ 2474 static int pl011_console_match(struct console *co, char *name, int idx, 2475 char *options) 2476 { 2477 unsigned char iotype; 2478 resource_size_t addr; 2479 int i; 2480 2481 /* 2482 * Systems affected by the Qualcomm Technologies QDF2400 E44 erratum 2483 * have a distinct console name, so make sure we check for that. 2484 * The actual implementation of the erratum occurs in the probe 2485 * function. 2486 */ 2487 if ((strcmp(name, "qdf2400_e44") != 0) && (strcmp(name, "pl011") != 0)) 2488 return -ENODEV; 2489 2490 if (uart_parse_earlycon(options, &iotype, &addr, &options)) 2491 return -ENODEV; 2492 2493 if (iotype != UPIO_MEM && iotype != UPIO_MEM32) 2494 return -ENODEV; 2495 2496 /* try to match the port specified on the command line */ 2497 for (i = 0; i < ARRAY_SIZE(amba_ports); i++) { 2498 struct uart_port *port; 2499 2500 if (!amba_ports[i]) 2501 continue; 2502 2503 port = &amba_ports[i]->port; 2504 2505 if (port->mapbase != addr) 2506 continue; 2507 2508 co->index = i; 2509 port->cons = co; 2510 return pl011_console_setup(co, options); 2511 } 2512 2513 return -ENODEV; 2514 } 2515 2516 static struct uart_driver amba_reg; 2517 static struct console amba_console = { 2518 .name = "ttyAMA", 2519 .write = pl011_console_write, 2520 .device = uart_console_device, 2521 .setup = pl011_console_setup, 2522 .match = pl011_console_match, 2523 .flags = CON_PRINTBUFFER | CON_ANYTIME, 2524 .index = -1, 2525 .data = &amba_reg, 2526 }; 2527 2528 #define AMBA_CONSOLE (&amba_console) 2529 2530 static void qdf2400_e44_putc(struct uart_port *port, unsigned char c) 2531 { 2532 while (readl(port->membase + UART01x_FR) & UART01x_FR_TXFF) 2533 cpu_relax(); 2534 writel(c, port->membase + UART01x_DR); 2535 while (!(readl(port->membase + UART01x_FR) & UART011_FR_TXFE)) 2536 cpu_relax(); 2537 } 2538 2539 static void qdf2400_e44_early_write(struct console *con, const char *s, unsigned n) 2540 { 2541 struct earlycon_device *dev = con->data; 2542 2543 uart_console_write(&dev->port, s, n, qdf2400_e44_putc); 2544 } 2545 2546 static void pl011_putc(struct uart_port *port, unsigned char c) 2547 { 2548 while (readl(port->membase + UART01x_FR) & UART01x_FR_TXFF) 2549 cpu_relax(); 2550 if (port->iotype == UPIO_MEM32) 2551 writel(c, port->membase + UART01x_DR); 2552 else 2553 writeb(c, port->membase + UART01x_DR); 2554 while (readl(port->membase + UART01x_FR) & UART01x_FR_BUSY) 2555 cpu_relax(); 2556 } 2557 2558 static void pl011_early_write(struct console *con, const char *s, unsigned n) 2559 { 2560 struct earlycon_device *dev = con->data; 2561 2562 uart_console_write(&dev->port, s, n, pl011_putc); 2563 } 2564 2565 #ifdef CONFIG_CONSOLE_POLL 2566 static int pl011_getc(struct uart_port *port) 2567 { 2568 if (readl(port->membase + UART01x_FR) & UART01x_FR_RXFE) 2569 return NO_POLL_CHAR; 2570 2571 if (port->iotype == UPIO_MEM32) 2572 return readl(port->membase + UART01x_DR); 2573 else 2574 return readb(port->membase + UART01x_DR); 2575 } 2576 2577 static int pl011_early_read(struct console *con, char *s, unsigned int n) 2578 { 2579 struct earlycon_device *dev = con->data; 2580 int ch, num_read = 0; 2581 2582 while (num_read < n) { 2583 ch = pl011_getc(&dev->port); 2584 if (ch == NO_POLL_CHAR) 2585 break; 2586 2587 s[num_read++] = ch; 2588 } 2589 2590 return num_read; 2591 } 2592 #else 2593 #define pl011_early_read NULL 2594 #endif 2595 2596 /* 2597 * On non-ACPI systems, earlycon is enabled by specifying 2598 * "earlycon=pl011,<address>" on the kernel command line. 2599 * 2600 * On ACPI ARM64 systems, an "early" console is enabled via the SPCR table, 2601 * by specifying only "earlycon" on the command line. Because it requires 2602 * SPCR, the console starts after ACPI is parsed, which is later than a 2603 * traditional early console. 2604 * 2605 * To get the traditional early console that starts before ACPI is parsed, 2606 * specify the full "earlycon=pl011,<address>" option. 2607 */ 2608 static int __init pl011_early_console_setup(struct earlycon_device *device, 2609 const char *opt) 2610 { 2611 if (!device->port.membase) 2612 return -ENODEV; 2613 2614 device->con->write = pl011_early_write; 2615 device->con->read = pl011_early_read; 2616 2617 return 0; 2618 } 2619 OF_EARLYCON_DECLARE(pl011, "arm,pl011", pl011_early_console_setup); 2620 OF_EARLYCON_DECLARE(pl011, "arm,sbsa-uart", pl011_early_console_setup); 2621 2622 /* 2623 * On Qualcomm Datacenter Technologies QDF2400 SOCs affected by 2624 * Erratum 44, traditional earlycon can be enabled by specifying 2625 * "earlycon=qdf2400_e44,<address>". Any options are ignored. 2626 * 2627 * Alternatively, you can just specify "earlycon", and the early console 2628 * will be enabled with the information from the SPCR table. In this 2629 * case, the SPCR code will detect the need for the E44 work-around, 2630 * and set the console name to "qdf2400_e44". 2631 */ 2632 static int __init 2633 qdf2400_e44_early_console_setup(struct earlycon_device *device, 2634 const char *opt) 2635 { 2636 if (!device->port.membase) 2637 return -ENODEV; 2638 2639 device->con->write = qdf2400_e44_early_write; 2640 return 0; 2641 } 2642 EARLYCON_DECLARE(qdf2400_e44, qdf2400_e44_early_console_setup); 2643 2644 #else 2645 #define AMBA_CONSOLE NULL 2646 #endif 2647 2648 static struct uart_driver amba_reg = { 2649 .owner = THIS_MODULE, 2650 .driver_name = "ttyAMA", 2651 .dev_name = "ttyAMA", 2652 .major = SERIAL_AMBA_MAJOR, 2653 .minor = SERIAL_AMBA_MINOR, 2654 .nr = UART_NR, 2655 .cons = AMBA_CONSOLE, 2656 }; 2657 2658 static int pl011_probe_dt_alias(int index, struct device *dev) 2659 { 2660 struct device_node *np; 2661 static bool seen_dev_with_alias = false; 2662 static bool seen_dev_without_alias = false; 2663 int ret = index; 2664 2665 if (!IS_ENABLED(CONFIG_OF)) 2666 return ret; 2667 2668 np = dev->of_node; 2669 if (!np) 2670 return ret; 2671 2672 ret = of_alias_get_id(np, "serial"); 2673 if (ret < 0) { 2674 seen_dev_without_alias = true; 2675 ret = index; 2676 } else { 2677 seen_dev_with_alias = true; 2678 if (ret >= ARRAY_SIZE(amba_ports) || amba_ports[ret] != NULL) { 2679 dev_warn(dev, "requested serial port %d not available.\n", ret); 2680 ret = index; 2681 } 2682 } 2683 2684 if (seen_dev_with_alias && seen_dev_without_alias) 2685 dev_warn(dev, "aliased and non-aliased serial devices found in device tree. Serial port enumeration may be unpredictable.\n"); 2686 2687 return ret; 2688 } 2689 2690 /* unregisters the driver also if no more ports are left */ 2691 static void pl011_unregister_port(struct uart_amba_port *uap) 2692 { 2693 int i; 2694 bool busy = false; 2695 2696 for (i = 0; i < ARRAY_SIZE(amba_ports); i++) { 2697 if (amba_ports[i] == uap) 2698 amba_ports[i] = NULL; 2699 else if (amba_ports[i]) 2700 busy = true; 2701 } 2702 pl011_dma_remove(uap); 2703 if (!busy) 2704 uart_unregister_driver(&amba_reg); 2705 } 2706 2707 static int pl011_find_free_port(void) 2708 { 2709 int i; 2710 2711 for (i = 0; i < ARRAY_SIZE(amba_ports); i++) 2712 if (amba_ports[i] == NULL) 2713 return i; 2714 2715 return -EBUSY; 2716 } 2717 2718 static int pl011_get_rs485_mode(struct uart_amba_port *uap) 2719 { 2720 struct uart_port *port = &uap->port; 2721 int ret; 2722 2723 ret = uart_get_rs485_mode(port); 2724 if (ret) 2725 return ret; 2726 2727 return 0; 2728 } 2729 2730 static int pl011_setup_port(struct device *dev, struct uart_amba_port *uap, 2731 struct resource *mmiobase, int index) 2732 { 2733 void __iomem *base; 2734 int ret; 2735 2736 base = devm_ioremap_resource(dev, mmiobase); 2737 if (IS_ERR(base)) 2738 return PTR_ERR(base); 2739 2740 index = pl011_probe_dt_alias(index, dev); 2741 2742 uap->port.dev = dev; 2743 uap->port.mapbase = mmiobase->start; 2744 uap->port.membase = base; 2745 uap->port.fifosize = uap->fifosize; 2746 uap->port.has_sysrq = IS_ENABLED(CONFIG_SERIAL_AMBA_PL011_CONSOLE); 2747 uap->port.flags = UPF_BOOT_AUTOCONF; 2748 uap->port.line = index; 2749 2750 ret = pl011_get_rs485_mode(uap); 2751 if (ret) 2752 return ret; 2753 2754 amba_ports[index] = uap; 2755 2756 return 0; 2757 } 2758 2759 static int pl011_register_port(struct uart_amba_port *uap) 2760 { 2761 int ret, i; 2762 2763 /* Ensure interrupts from this UART are masked and cleared */ 2764 pl011_write(0, uap, REG_IMSC); 2765 pl011_write(0xffff, uap, REG_ICR); 2766 2767 if (!amba_reg.state) { 2768 ret = uart_register_driver(&amba_reg); 2769 if (ret < 0) { 2770 dev_err(uap->port.dev, 2771 "Failed to register AMBA-PL011 driver\n"); 2772 for (i = 0; i < ARRAY_SIZE(amba_ports); i++) 2773 if (amba_ports[i] == uap) 2774 amba_ports[i] = NULL; 2775 return ret; 2776 } 2777 } 2778 2779 ret = uart_add_one_port(&amba_reg, &uap->port); 2780 if (ret) 2781 pl011_unregister_port(uap); 2782 2783 return ret; 2784 } 2785 2786 static const struct serial_rs485 pl011_rs485_supported = { 2787 .flags = SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND | SER_RS485_RTS_AFTER_SEND | 2788 SER_RS485_RX_DURING_TX, 2789 .delay_rts_before_send = 1, 2790 .delay_rts_after_send = 1, 2791 }; 2792 2793 static int pl011_probe(struct amba_device *dev, const struct amba_id *id) 2794 { 2795 struct uart_amba_port *uap; 2796 struct vendor_data *vendor = id->data; 2797 int portnr, ret; 2798 u32 val; 2799 2800 portnr = pl011_find_free_port(); 2801 if (portnr < 0) 2802 return portnr; 2803 2804 uap = devm_kzalloc(&dev->dev, sizeof(struct uart_amba_port), 2805 GFP_KERNEL); 2806 if (!uap) 2807 return -ENOMEM; 2808 2809 uap->clk = devm_clk_get(&dev->dev, NULL); 2810 if (IS_ERR(uap->clk)) 2811 return PTR_ERR(uap->clk); 2812 2813 uap->reg_offset = vendor->reg_offset; 2814 uap->vendor = vendor; 2815 uap->fifosize = vendor->get_fifosize(dev); 2816 uap->port.iotype = vendor->access_32b ? UPIO_MEM32 : UPIO_MEM; 2817 uap->port.irq = dev->irq[0]; 2818 uap->port.ops = &amba_pl011_pops; 2819 uap->port.rs485_config = pl011_rs485_config; 2820 uap->port.rs485_supported = pl011_rs485_supported; 2821 snprintf(uap->type, sizeof(uap->type), "PL011 rev%u", amba_rev(dev)); 2822 2823 if (device_property_read_u32(&dev->dev, "reg-io-width", &val) == 0) { 2824 switch (val) { 2825 case 1: 2826 uap->port.iotype = UPIO_MEM; 2827 break; 2828 case 4: 2829 uap->port.iotype = UPIO_MEM32; 2830 break; 2831 default: 2832 dev_warn(&dev->dev, "unsupported reg-io-width (%d)\n", 2833 val); 2834 return -EINVAL; 2835 } 2836 } 2837 2838 ret = pl011_setup_port(&dev->dev, uap, &dev->res, portnr); 2839 if (ret) 2840 return ret; 2841 2842 amba_set_drvdata(dev, uap); 2843 2844 return pl011_register_port(uap); 2845 } 2846 2847 static void pl011_remove(struct amba_device *dev) 2848 { 2849 struct uart_amba_port *uap = amba_get_drvdata(dev); 2850 2851 uart_remove_one_port(&amba_reg, &uap->port); 2852 pl011_unregister_port(uap); 2853 } 2854 2855 #ifdef CONFIG_PM_SLEEP 2856 static int pl011_suspend(struct device *dev) 2857 { 2858 struct uart_amba_port *uap = dev_get_drvdata(dev); 2859 2860 if (!uap) 2861 return -EINVAL; 2862 2863 return uart_suspend_port(&amba_reg, &uap->port); 2864 } 2865 2866 static int pl011_resume(struct device *dev) 2867 { 2868 struct uart_amba_port *uap = dev_get_drvdata(dev); 2869 2870 if (!uap) 2871 return -EINVAL; 2872 2873 return uart_resume_port(&amba_reg, &uap->port); 2874 } 2875 #endif 2876 2877 static SIMPLE_DEV_PM_OPS(pl011_dev_pm_ops, pl011_suspend, pl011_resume); 2878 2879 static int sbsa_uart_probe(struct platform_device *pdev) 2880 { 2881 struct uart_amba_port *uap; 2882 struct resource *r; 2883 int portnr, ret; 2884 int baudrate; 2885 2886 /* 2887 * Check the mandatory baud rate parameter in the DT node early 2888 * so that we can easily exit with the error. 2889 */ 2890 if (pdev->dev.of_node) { 2891 struct device_node *np = pdev->dev.of_node; 2892 2893 ret = of_property_read_u32(np, "current-speed", &baudrate); 2894 if (ret) 2895 return ret; 2896 } else { 2897 baudrate = 115200; 2898 } 2899 2900 portnr = pl011_find_free_port(); 2901 if (portnr < 0) 2902 return portnr; 2903 2904 uap = devm_kzalloc(&pdev->dev, sizeof(struct uart_amba_port), 2905 GFP_KERNEL); 2906 if (!uap) 2907 return -ENOMEM; 2908 2909 ret = platform_get_irq(pdev, 0); 2910 if (ret < 0) 2911 return ret; 2912 uap->port.irq = ret; 2913 2914 #ifdef CONFIG_ACPI_SPCR_TABLE 2915 if (qdf2400_e44_present) { 2916 dev_info(&pdev->dev, "working around QDF2400 SoC erratum 44\n"); 2917 uap->vendor = &vendor_qdt_qdf2400_e44; 2918 } else 2919 #endif 2920 uap->vendor = &vendor_sbsa; 2921 2922 uap->reg_offset = uap->vendor->reg_offset; 2923 uap->fifosize = 32; 2924 uap->port.iotype = uap->vendor->access_32b ? UPIO_MEM32 : UPIO_MEM; 2925 uap->port.ops = &sbsa_uart_pops; 2926 uap->fixed_baud = baudrate; 2927 2928 snprintf(uap->type, sizeof(uap->type), "SBSA"); 2929 2930 r = platform_get_resource(pdev, IORESOURCE_MEM, 0); 2931 2932 ret = pl011_setup_port(&pdev->dev, uap, r, portnr); 2933 if (ret) 2934 return ret; 2935 2936 platform_set_drvdata(pdev, uap); 2937 2938 return pl011_register_port(uap); 2939 } 2940 2941 static int sbsa_uart_remove(struct platform_device *pdev) 2942 { 2943 struct uart_amba_port *uap = platform_get_drvdata(pdev); 2944 2945 uart_remove_one_port(&amba_reg, &uap->port); 2946 pl011_unregister_port(uap); 2947 return 0; 2948 } 2949 2950 static const struct of_device_id sbsa_uart_of_match[] = { 2951 { .compatible = "arm,sbsa-uart", }, 2952 {}, 2953 }; 2954 MODULE_DEVICE_TABLE(of, sbsa_uart_of_match); 2955 2956 static const struct acpi_device_id __maybe_unused sbsa_uart_acpi_match[] = { 2957 { "ARMH0011", 0 }, 2958 { "ARMHB000", 0 }, 2959 {}, 2960 }; 2961 MODULE_DEVICE_TABLE(acpi, sbsa_uart_acpi_match); 2962 2963 static struct platform_driver arm_sbsa_uart_platform_driver = { 2964 .probe = sbsa_uart_probe, 2965 .remove = sbsa_uart_remove, 2966 .driver = { 2967 .name = "sbsa-uart", 2968 .pm = &pl011_dev_pm_ops, 2969 .of_match_table = of_match_ptr(sbsa_uart_of_match), 2970 .acpi_match_table = ACPI_PTR(sbsa_uart_acpi_match), 2971 .suppress_bind_attrs = IS_BUILTIN(CONFIG_SERIAL_AMBA_PL011), 2972 }, 2973 }; 2974 2975 static const struct amba_id pl011_ids[] = { 2976 { 2977 .id = 0x00041011, 2978 .mask = 0x000fffff, 2979 .data = &vendor_arm, 2980 }, 2981 { 2982 .id = 0x00380802, 2983 .mask = 0x00ffffff, 2984 .data = &vendor_st, 2985 }, 2986 { 0, 0 }, 2987 }; 2988 2989 MODULE_DEVICE_TABLE(amba, pl011_ids); 2990 2991 static struct amba_driver pl011_driver = { 2992 .drv = { 2993 .name = "uart-pl011", 2994 .pm = &pl011_dev_pm_ops, 2995 .suppress_bind_attrs = IS_BUILTIN(CONFIG_SERIAL_AMBA_PL011), 2996 }, 2997 .id_table = pl011_ids, 2998 .probe = pl011_probe, 2999 .remove = pl011_remove, 3000 }; 3001 3002 static int __init pl011_init(void) 3003 { 3004 printk(KERN_INFO "Serial: AMBA PL011 UART driver\n"); 3005 3006 if (platform_driver_register(&arm_sbsa_uart_platform_driver)) 3007 pr_warn("could not register SBSA UART platform driver\n"); 3008 return amba_driver_register(&pl011_driver); 3009 } 3010 3011 static void __exit pl011_exit(void) 3012 { 3013 platform_driver_unregister(&arm_sbsa_uart_platform_driver); 3014 amba_driver_unregister(&pl011_driver); 3015 } 3016 3017 /* 3018 * While this can be a module, if builtin it's most likely the console 3019 * So let's leave module_exit but move module_init to an earlier place 3020 */ 3021 arch_initcall(pl011_init); 3022 module_exit(pl011_exit); 3023 3024 MODULE_AUTHOR("ARM Ltd/Deep Blue Solutions Ltd"); 3025 MODULE_DESCRIPTION("ARM AMBA serial port driver"); 3026 MODULE_LICENSE("GPL"); 3027