1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * serial_tegra.c 4 * 5 * High-speed serial driver for NVIDIA Tegra SoCs 6 * 7 * Copyright (c) 2012-2019, NVIDIA CORPORATION. All rights reserved. 8 * 9 * Author: Laxman Dewangan <ldewangan@nvidia.com> 10 */ 11 12 #include <linux/clk.h> 13 #include <linux/debugfs.h> 14 #include <linux/delay.h> 15 #include <linux/dmaengine.h> 16 #include <linux/dma-mapping.h> 17 #include <linux/dmapool.h> 18 #include <linux/err.h> 19 #include <linux/io.h> 20 #include <linux/irq.h> 21 #include <linux/module.h> 22 #include <linux/of.h> 23 #include <linux/of_device.h> 24 #include <linux/pagemap.h> 25 #include <linux/platform_device.h> 26 #include <linux/reset.h> 27 #include <linux/serial.h> 28 #include <linux/serial_8250.h> 29 #include <linux/serial_core.h> 30 #include <linux/serial_reg.h> 31 #include <linux/slab.h> 32 #include <linux/string.h> 33 #include <linux/termios.h> 34 #include <linux/tty.h> 35 #include <linux/tty_flip.h> 36 37 #define TEGRA_UART_TYPE "TEGRA_UART" 38 #define TX_EMPTY_STATUS (UART_LSR_TEMT | UART_LSR_THRE) 39 #define BYTES_TO_ALIGN(x) ((unsigned long)(x) & 0x3) 40 41 #define TEGRA_UART_RX_DMA_BUFFER_SIZE 4096 42 #define TEGRA_UART_LSR_TXFIFO_FULL 0x100 43 #define TEGRA_UART_IER_EORD 0x20 44 #define TEGRA_UART_MCR_RTS_EN 0x40 45 #define TEGRA_UART_MCR_CTS_EN 0x20 46 #define TEGRA_UART_LSR_ANY (UART_LSR_OE | UART_LSR_BI | \ 47 UART_LSR_PE | UART_LSR_FE) 48 #define TEGRA_UART_IRDA_CSR 0x08 49 #define TEGRA_UART_SIR_ENABLED 0x80 50 51 #define TEGRA_UART_TX_PIO 1 52 #define TEGRA_UART_TX_DMA 2 53 #define TEGRA_UART_MIN_DMA 16 54 #define TEGRA_UART_FIFO_SIZE 32 55 56 /* 57 * Tx fifo trigger level setting in tegra uart is in 58 * reverse way then conventional uart. 59 */ 60 #define TEGRA_UART_TX_TRIG_16B 0x00 61 #define TEGRA_UART_TX_TRIG_8B 0x10 62 #define TEGRA_UART_TX_TRIG_4B 0x20 63 #define TEGRA_UART_TX_TRIG_1B 0x30 64 65 #define TEGRA_UART_MAXIMUM 8 66 67 /* Default UART setting when started: 115200 no parity, stop, 8 data bits */ 68 #define TEGRA_UART_DEFAULT_BAUD 115200 69 #define TEGRA_UART_DEFAULT_LSR UART_LCR_WLEN8 70 71 /* Tx transfer mode */ 72 #define TEGRA_TX_PIO 1 73 #define TEGRA_TX_DMA 2 74 75 #define TEGRA_UART_FCR_IIR_FIFO_EN 0x40 76 77 /** 78 * tegra_uart_chip_data: SOC specific data. 79 * 80 * @tx_fifo_full_status: Status flag available for checking tx fifo full. 81 * @allow_txfifo_reset_fifo_mode: allow_tx fifo reset with fifo mode or not. 82 * Tegra30 does not allow this. 83 * @support_clk_src_div: Clock source support the clock divider. 84 */ 85 struct tegra_uart_chip_data { 86 bool tx_fifo_full_status; 87 bool allow_txfifo_reset_fifo_mode; 88 bool support_clk_src_div; 89 bool fifo_mode_enable_status; 90 int uart_max_port; 91 int max_dma_burst_bytes; 92 int error_tolerance_low_range; 93 int error_tolerance_high_range; 94 }; 95 96 struct tegra_baud_tolerance { 97 u32 lower_range_baud; 98 u32 upper_range_baud; 99 s32 tolerance; 100 }; 101 102 struct tegra_uart_port { 103 struct uart_port uport; 104 const struct tegra_uart_chip_data *cdata; 105 106 struct clk *uart_clk; 107 struct reset_control *rst; 108 unsigned int current_baud; 109 110 /* Register shadow */ 111 unsigned long fcr_shadow; 112 unsigned long mcr_shadow; 113 unsigned long lcr_shadow; 114 unsigned long ier_shadow; 115 bool rts_active; 116 117 int tx_in_progress; 118 unsigned int tx_bytes; 119 120 bool enable_modem_interrupt; 121 122 bool rx_timeout; 123 int rx_in_progress; 124 int symb_bit; 125 126 struct dma_chan *rx_dma_chan; 127 struct dma_chan *tx_dma_chan; 128 dma_addr_t rx_dma_buf_phys; 129 dma_addr_t tx_dma_buf_phys; 130 unsigned char *rx_dma_buf_virt; 131 unsigned char *tx_dma_buf_virt; 132 struct dma_async_tx_descriptor *tx_dma_desc; 133 struct dma_async_tx_descriptor *rx_dma_desc; 134 dma_cookie_t tx_cookie; 135 dma_cookie_t rx_cookie; 136 unsigned int tx_bytes_requested; 137 unsigned int rx_bytes_requested; 138 struct tegra_baud_tolerance *baud_tolerance; 139 int n_adjustable_baud_rates; 140 int required_rate; 141 int configured_rate; 142 bool use_rx_pio; 143 bool use_tx_pio; 144 }; 145 146 static void tegra_uart_start_next_tx(struct tegra_uart_port *tup); 147 static int tegra_uart_start_rx_dma(struct tegra_uart_port *tup); 148 static void tegra_uart_dma_channel_free(struct tegra_uart_port *tup, 149 bool dma_to_memory); 150 151 static inline unsigned long tegra_uart_read(struct tegra_uart_port *tup, 152 unsigned long reg) 153 { 154 return readl(tup->uport.membase + (reg << tup->uport.regshift)); 155 } 156 157 static inline void tegra_uart_write(struct tegra_uart_port *tup, unsigned val, 158 unsigned long reg) 159 { 160 writel(val, tup->uport.membase + (reg << tup->uport.regshift)); 161 } 162 163 static inline struct tegra_uart_port *to_tegra_uport(struct uart_port *u) 164 { 165 return container_of(u, struct tegra_uart_port, uport); 166 } 167 168 static unsigned int tegra_uart_get_mctrl(struct uart_port *u) 169 { 170 struct tegra_uart_port *tup = to_tegra_uport(u); 171 172 /* 173 * RI - Ring detector is active 174 * CD/DCD/CAR - Carrier detect is always active. For some reason 175 * linux has different names for carrier detect. 176 * DSR - Data Set ready is active as the hardware doesn't support it. 177 * Don't know if the linux support this yet? 178 * CTS - Clear to send. Always set to active, as the hardware handles 179 * CTS automatically. 180 */ 181 if (tup->enable_modem_interrupt) 182 return TIOCM_RI | TIOCM_CD | TIOCM_DSR | TIOCM_CTS; 183 return TIOCM_CTS; 184 } 185 186 static void set_rts(struct tegra_uart_port *tup, bool active) 187 { 188 unsigned long mcr; 189 190 mcr = tup->mcr_shadow; 191 if (active) 192 mcr |= TEGRA_UART_MCR_RTS_EN; 193 else 194 mcr &= ~TEGRA_UART_MCR_RTS_EN; 195 if (mcr != tup->mcr_shadow) { 196 tegra_uart_write(tup, mcr, UART_MCR); 197 tup->mcr_shadow = mcr; 198 } 199 } 200 201 static void set_dtr(struct tegra_uart_port *tup, bool active) 202 { 203 unsigned long mcr; 204 205 mcr = tup->mcr_shadow; 206 if (active) 207 mcr |= UART_MCR_DTR; 208 else 209 mcr &= ~UART_MCR_DTR; 210 if (mcr != tup->mcr_shadow) { 211 tegra_uart_write(tup, mcr, UART_MCR); 212 tup->mcr_shadow = mcr; 213 } 214 } 215 216 static void set_loopbk(struct tegra_uart_port *tup, bool active) 217 { 218 unsigned long mcr = tup->mcr_shadow; 219 220 if (active) 221 mcr |= UART_MCR_LOOP; 222 else 223 mcr &= ~UART_MCR_LOOP; 224 225 if (mcr != tup->mcr_shadow) { 226 tegra_uart_write(tup, mcr, UART_MCR); 227 tup->mcr_shadow = mcr; 228 } 229 } 230 231 static void tegra_uart_set_mctrl(struct uart_port *u, unsigned int mctrl) 232 { 233 struct tegra_uart_port *tup = to_tegra_uport(u); 234 int enable; 235 236 tup->rts_active = !!(mctrl & TIOCM_RTS); 237 set_rts(tup, tup->rts_active); 238 239 enable = !!(mctrl & TIOCM_DTR); 240 set_dtr(tup, enable); 241 242 enable = !!(mctrl & TIOCM_LOOP); 243 set_loopbk(tup, enable); 244 } 245 246 static void tegra_uart_break_ctl(struct uart_port *u, int break_ctl) 247 { 248 struct tegra_uart_port *tup = to_tegra_uport(u); 249 unsigned long lcr; 250 251 lcr = tup->lcr_shadow; 252 if (break_ctl) 253 lcr |= UART_LCR_SBC; 254 else 255 lcr &= ~UART_LCR_SBC; 256 tegra_uart_write(tup, lcr, UART_LCR); 257 tup->lcr_shadow = lcr; 258 } 259 260 /** 261 * tegra_uart_wait_cycle_time: Wait for N UART clock periods 262 * 263 * @tup: Tegra serial port data structure. 264 * @cycles: Number of clock periods to wait. 265 * 266 * Tegra UARTs are clocked at 16X the baud/bit rate and hence the UART 267 * clock speed is 16X the current baud rate. 268 */ 269 static void tegra_uart_wait_cycle_time(struct tegra_uart_port *tup, 270 unsigned int cycles) 271 { 272 if (tup->current_baud) 273 udelay(DIV_ROUND_UP(cycles * 1000000, tup->current_baud * 16)); 274 } 275 276 /* Wait for a symbol-time. */ 277 static void tegra_uart_wait_sym_time(struct tegra_uart_port *tup, 278 unsigned int syms) 279 { 280 if (tup->current_baud) 281 udelay(DIV_ROUND_UP(syms * tup->symb_bit * 1000000, 282 tup->current_baud)); 283 } 284 285 static int tegra_uart_wait_fifo_mode_enabled(struct tegra_uart_port *tup) 286 { 287 unsigned long iir; 288 unsigned int tmout = 100; 289 290 do { 291 iir = tegra_uart_read(tup, UART_IIR); 292 if (iir & TEGRA_UART_FCR_IIR_FIFO_EN) 293 return 0; 294 udelay(1); 295 } while (--tmout); 296 297 return -ETIMEDOUT; 298 } 299 300 static void tegra_uart_fifo_reset(struct tegra_uart_port *tup, u8 fcr_bits) 301 { 302 unsigned long fcr = tup->fcr_shadow; 303 unsigned int lsr, tmout = 10000; 304 305 if (tup->rts_active) 306 set_rts(tup, false); 307 308 if (tup->cdata->allow_txfifo_reset_fifo_mode) { 309 fcr |= fcr_bits & (UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT); 310 tegra_uart_write(tup, fcr, UART_FCR); 311 } else { 312 fcr &= ~UART_FCR_ENABLE_FIFO; 313 tegra_uart_write(tup, fcr, UART_FCR); 314 udelay(60); 315 fcr |= fcr_bits & (UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT); 316 tegra_uart_write(tup, fcr, UART_FCR); 317 fcr |= UART_FCR_ENABLE_FIFO; 318 tegra_uart_write(tup, fcr, UART_FCR); 319 if (tup->cdata->fifo_mode_enable_status) 320 tegra_uart_wait_fifo_mode_enabled(tup); 321 } 322 323 /* Dummy read to ensure the write is posted */ 324 tegra_uart_read(tup, UART_SCR); 325 326 /* 327 * For all tegra devices (up to t210), there is a hardware issue that 328 * requires software to wait for 32 UART clock periods for the flush 329 * to propagate, otherwise data could be lost. 330 */ 331 tegra_uart_wait_cycle_time(tup, 32); 332 333 do { 334 lsr = tegra_uart_read(tup, UART_LSR); 335 if ((lsr | UART_LSR_TEMT) && !(lsr & UART_LSR_DR)) 336 break; 337 udelay(1); 338 } while (--tmout); 339 340 if (tup->rts_active) 341 set_rts(tup, true); 342 } 343 344 static long tegra_get_tolerance_rate(struct tegra_uart_port *tup, 345 unsigned int baud, long rate) 346 { 347 int i; 348 349 for (i = 0; i < tup->n_adjustable_baud_rates; ++i) { 350 if (baud >= tup->baud_tolerance[i].lower_range_baud && 351 baud <= tup->baud_tolerance[i].upper_range_baud) 352 return (rate + (rate * 353 tup->baud_tolerance[i].tolerance) / 10000); 354 } 355 356 return rate; 357 } 358 359 static int tegra_check_rate_in_range(struct tegra_uart_port *tup) 360 { 361 long diff; 362 363 diff = ((long)(tup->configured_rate - tup->required_rate) * 10000) 364 / tup->required_rate; 365 if (diff < (tup->cdata->error_tolerance_low_range * 100) || 366 diff > (tup->cdata->error_tolerance_high_range * 100)) { 367 dev_err(tup->uport.dev, 368 "configured baud rate is out of range by %ld", diff); 369 return -EIO; 370 } 371 372 return 0; 373 } 374 375 static int tegra_set_baudrate(struct tegra_uart_port *tup, unsigned int baud) 376 { 377 unsigned long rate; 378 unsigned int divisor; 379 unsigned long lcr; 380 unsigned long flags; 381 int ret; 382 383 if (tup->current_baud == baud) 384 return 0; 385 386 if (tup->cdata->support_clk_src_div) { 387 rate = baud * 16; 388 tup->required_rate = rate; 389 390 if (tup->n_adjustable_baud_rates) 391 rate = tegra_get_tolerance_rate(tup, baud, rate); 392 393 ret = clk_set_rate(tup->uart_clk, rate); 394 if (ret < 0) { 395 dev_err(tup->uport.dev, 396 "clk_set_rate() failed for rate %lu\n", rate); 397 return ret; 398 } 399 tup->configured_rate = clk_get_rate(tup->uart_clk); 400 divisor = 1; 401 ret = tegra_check_rate_in_range(tup); 402 if (ret < 0) 403 return ret; 404 } else { 405 rate = clk_get_rate(tup->uart_clk); 406 divisor = DIV_ROUND_CLOSEST(rate, baud * 16); 407 } 408 409 spin_lock_irqsave(&tup->uport.lock, flags); 410 lcr = tup->lcr_shadow; 411 lcr |= UART_LCR_DLAB; 412 tegra_uart_write(tup, lcr, UART_LCR); 413 414 tegra_uart_write(tup, divisor & 0xFF, UART_TX); 415 tegra_uart_write(tup, ((divisor >> 8) & 0xFF), UART_IER); 416 417 lcr &= ~UART_LCR_DLAB; 418 tegra_uart_write(tup, lcr, UART_LCR); 419 420 /* Dummy read to ensure the write is posted */ 421 tegra_uart_read(tup, UART_SCR); 422 spin_unlock_irqrestore(&tup->uport.lock, flags); 423 424 tup->current_baud = baud; 425 426 /* wait two character intervals at new rate */ 427 tegra_uart_wait_sym_time(tup, 2); 428 return 0; 429 } 430 431 static char tegra_uart_decode_rx_error(struct tegra_uart_port *tup, 432 unsigned long lsr) 433 { 434 char flag = TTY_NORMAL; 435 436 if (unlikely(lsr & TEGRA_UART_LSR_ANY)) { 437 if (lsr & UART_LSR_OE) { 438 /* Overrrun error */ 439 flag = TTY_OVERRUN; 440 tup->uport.icount.overrun++; 441 dev_err(tup->uport.dev, "Got overrun errors\n"); 442 } else if (lsr & UART_LSR_PE) { 443 /* Parity error */ 444 flag = TTY_PARITY; 445 tup->uport.icount.parity++; 446 dev_err(tup->uport.dev, "Got Parity errors\n"); 447 } else if (lsr & UART_LSR_FE) { 448 flag = TTY_FRAME; 449 tup->uport.icount.frame++; 450 dev_err(tup->uport.dev, "Got frame errors\n"); 451 } else if (lsr & UART_LSR_BI) { 452 /* 453 * Break error 454 * If FIFO read error without any data, reset Rx FIFO 455 */ 456 if (!(lsr & UART_LSR_DR) && (lsr & UART_LSR_FIFOE)) 457 tegra_uart_fifo_reset(tup, UART_FCR_CLEAR_RCVR); 458 if (tup->uport.ignore_status_mask & UART_LSR_BI) 459 return TTY_BREAK; 460 flag = TTY_BREAK; 461 tup->uport.icount.brk++; 462 dev_dbg(tup->uport.dev, "Got Break\n"); 463 } 464 uart_insert_char(&tup->uport, lsr, UART_LSR_OE, 0, flag); 465 } 466 467 return flag; 468 } 469 470 static int tegra_uart_request_port(struct uart_port *u) 471 { 472 return 0; 473 } 474 475 static void tegra_uart_release_port(struct uart_port *u) 476 { 477 /* Nothing to do here */ 478 } 479 480 static void tegra_uart_fill_tx_fifo(struct tegra_uart_port *tup, int max_bytes) 481 { 482 struct circ_buf *xmit = &tup->uport.state->xmit; 483 int i; 484 485 for (i = 0; i < max_bytes; i++) { 486 BUG_ON(uart_circ_empty(xmit)); 487 if (tup->cdata->tx_fifo_full_status) { 488 unsigned long lsr = tegra_uart_read(tup, UART_LSR); 489 if ((lsr & TEGRA_UART_LSR_TXFIFO_FULL)) 490 break; 491 } 492 tegra_uart_write(tup, xmit->buf[xmit->tail], UART_TX); 493 xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1); 494 tup->uport.icount.tx++; 495 } 496 } 497 498 static void tegra_uart_start_pio_tx(struct tegra_uart_port *tup, 499 unsigned int bytes) 500 { 501 if (bytes > TEGRA_UART_MIN_DMA) 502 bytes = TEGRA_UART_MIN_DMA; 503 504 tup->tx_in_progress = TEGRA_UART_TX_PIO; 505 tup->tx_bytes = bytes; 506 tup->ier_shadow |= UART_IER_THRI; 507 tegra_uart_write(tup, tup->ier_shadow, UART_IER); 508 } 509 510 static void tegra_uart_tx_dma_complete(void *args) 511 { 512 struct tegra_uart_port *tup = args; 513 struct circ_buf *xmit = &tup->uport.state->xmit; 514 struct dma_tx_state state; 515 unsigned long flags; 516 unsigned int count; 517 518 dmaengine_tx_status(tup->tx_dma_chan, tup->tx_cookie, &state); 519 count = tup->tx_bytes_requested - state.residue; 520 async_tx_ack(tup->tx_dma_desc); 521 spin_lock_irqsave(&tup->uport.lock, flags); 522 xmit->tail = (xmit->tail + count) & (UART_XMIT_SIZE - 1); 523 tup->tx_in_progress = 0; 524 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) 525 uart_write_wakeup(&tup->uport); 526 tegra_uart_start_next_tx(tup); 527 spin_unlock_irqrestore(&tup->uport.lock, flags); 528 } 529 530 static int tegra_uart_start_tx_dma(struct tegra_uart_port *tup, 531 unsigned long count) 532 { 533 struct circ_buf *xmit = &tup->uport.state->xmit; 534 dma_addr_t tx_phys_addr; 535 536 dma_sync_single_for_device(tup->uport.dev, tup->tx_dma_buf_phys, 537 UART_XMIT_SIZE, DMA_TO_DEVICE); 538 539 tup->tx_bytes = count & ~(0xF); 540 tx_phys_addr = tup->tx_dma_buf_phys + xmit->tail; 541 tup->tx_dma_desc = dmaengine_prep_slave_single(tup->tx_dma_chan, 542 tx_phys_addr, tup->tx_bytes, DMA_MEM_TO_DEV, 543 DMA_PREP_INTERRUPT); 544 if (!tup->tx_dma_desc) { 545 dev_err(tup->uport.dev, "Not able to get desc for Tx\n"); 546 return -EIO; 547 } 548 549 tup->tx_dma_desc->callback = tegra_uart_tx_dma_complete; 550 tup->tx_dma_desc->callback_param = tup; 551 tup->tx_in_progress = TEGRA_UART_TX_DMA; 552 tup->tx_bytes_requested = tup->tx_bytes; 553 tup->tx_cookie = dmaengine_submit(tup->tx_dma_desc); 554 dma_async_issue_pending(tup->tx_dma_chan); 555 return 0; 556 } 557 558 static void tegra_uart_start_next_tx(struct tegra_uart_port *tup) 559 { 560 unsigned long tail; 561 unsigned long count; 562 struct circ_buf *xmit = &tup->uport.state->xmit; 563 564 if (!tup->current_baud) 565 return; 566 567 tail = (unsigned long)&xmit->buf[xmit->tail]; 568 count = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE); 569 if (!count) 570 return; 571 572 if (tup->use_tx_pio || count < TEGRA_UART_MIN_DMA) 573 tegra_uart_start_pio_tx(tup, count); 574 else if (BYTES_TO_ALIGN(tail) > 0) 575 tegra_uart_start_pio_tx(tup, BYTES_TO_ALIGN(tail)); 576 else 577 tegra_uart_start_tx_dma(tup, count); 578 } 579 580 /* Called by serial core driver with u->lock taken. */ 581 static void tegra_uart_start_tx(struct uart_port *u) 582 { 583 struct tegra_uart_port *tup = to_tegra_uport(u); 584 struct circ_buf *xmit = &u->state->xmit; 585 586 if (!uart_circ_empty(xmit) && !tup->tx_in_progress) 587 tegra_uart_start_next_tx(tup); 588 } 589 590 static unsigned int tegra_uart_tx_empty(struct uart_port *u) 591 { 592 struct tegra_uart_port *tup = to_tegra_uport(u); 593 unsigned int ret = 0; 594 unsigned long flags; 595 596 spin_lock_irqsave(&u->lock, flags); 597 if (!tup->tx_in_progress) { 598 unsigned long lsr = tegra_uart_read(tup, UART_LSR); 599 if ((lsr & TX_EMPTY_STATUS) == TX_EMPTY_STATUS) 600 ret = TIOCSER_TEMT; 601 } 602 spin_unlock_irqrestore(&u->lock, flags); 603 return ret; 604 } 605 606 static void tegra_uart_stop_tx(struct uart_port *u) 607 { 608 struct tegra_uart_port *tup = to_tegra_uport(u); 609 struct circ_buf *xmit = &tup->uport.state->xmit; 610 struct dma_tx_state state; 611 unsigned int count; 612 613 if (tup->tx_in_progress != TEGRA_UART_TX_DMA) 614 return; 615 616 dmaengine_terminate_all(tup->tx_dma_chan); 617 dmaengine_tx_status(tup->tx_dma_chan, tup->tx_cookie, &state); 618 count = tup->tx_bytes_requested - state.residue; 619 async_tx_ack(tup->tx_dma_desc); 620 xmit->tail = (xmit->tail + count) & (UART_XMIT_SIZE - 1); 621 tup->tx_in_progress = 0; 622 } 623 624 static void tegra_uart_handle_tx_pio(struct tegra_uart_port *tup) 625 { 626 struct circ_buf *xmit = &tup->uport.state->xmit; 627 628 tegra_uart_fill_tx_fifo(tup, tup->tx_bytes); 629 tup->tx_in_progress = 0; 630 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) 631 uart_write_wakeup(&tup->uport); 632 tegra_uart_start_next_tx(tup); 633 } 634 635 static void tegra_uart_handle_rx_pio(struct tegra_uart_port *tup, 636 struct tty_port *tty) 637 { 638 do { 639 char flag = TTY_NORMAL; 640 unsigned long lsr = 0; 641 unsigned char ch; 642 643 lsr = tegra_uart_read(tup, UART_LSR); 644 if (!(lsr & UART_LSR_DR)) 645 break; 646 647 flag = tegra_uart_decode_rx_error(tup, lsr); 648 if (flag != TTY_NORMAL) 649 continue; 650 651 ch = (unsigned char) tegra_uart_read(tup, UART_RX); 652 tup->uport.icount.rx++; 653 654 if (!uart_handle_sysrq_char(&tup->uport, ch) && tty) 655 tty_insert_flip_char(tty, ch, flag); 656 657 if (tup->uport.ignore_status_mask & UART_LSR_DR) 658 continue; 659 } while (1); 660 } 661 662 static void tegra_uart_copy_rx_to_tty(struct tegra_uart_port *tup, 663 struct tty_port *tty, 664 unsigned int count) 665 { 666 int copied; 667 668 /* If count is zero, then there is no data to be copied */ 669 if (!count) 670 return; 671 672 tup->uport.icount.rx += count; 673 if (!tty) { 674 dev_err(tup->uport.dev, "No tty port\n"); 675 return; 676 } 677 678 if (tup->uport.ignore_status_mask & UART_LSR_DR) 679 return; 680 681 dma_sync_single_for_cpu(tup->uport.dev, tup->rx_dma_buf_phys, 682 TEGRA_UART_RX_DMA_BUFFER_SIZE, DMA_FROM_DEVICE); 683 copied = tty_insert_flip_string(tty, 684 ((unsigned char *)(tup->rx_dma_buf_virt)), count); 685 if (copied != count) { 686 WARN_ON(1); 687 dev_err(tup->uport.dev, "RxData copy to tty layer failed\n"); 688 } 689 dma_sync_single_for_device(tup->uport.dev, tup->rx_dma_buf_phys, 690 TEGRA_UART_RX_DMA_BUFFER_SIZE, DMA_TO_DEVICE); 691 } 692 693 static void tegra_uart_rx_buffer_push(struct tegra_uart_port *tup, 694 unsigned int residue) 695 { 696 struct tty_port *port = &tup->uport.state->port; 697 struct tty_struct *tty = tty_port_tty_get(port); 698 unsigned int count; 699 700 async_tx_ack(tup->rx_dma_desc); 701 count = tup->rx_bytes_requested - residue; 702 703 /* If we are here, DMA is stopped */ 704 tegra_uart_copy_rx_to_tty(tup, port, count); 705 706 tegra_uart_handle_rx_pio(tup, port); 707 if (tty) { 708 tty_flip_buffer_push(port); 709 tty_kref_put(tty); 710 } 711 } 712 713 static void tegra_uart_rx_dma_complete(void *args) 714 { 715 struct tegra_uart_port *tup = args; 716 struct uart_port *u = &tup->uport; 717 unsigned long flags; 718 struct dma_tx_state state; 719 enum dma_status status; 720 721 spin_lock_irqsave(&u->lock, flags); 722 723 status = dmaengine_tx_status(tup->rx_dma_chan, tup->rx_cookie, &state); 724 725 if (status == DMA_IN_PROGRESS) { 726 dev_dbg(tup->uport.dev, "RX DMA is in progress\n"); 727 goto done; 728 } 729 730 /* Deactivate flow control to stop sender */ 731 if (tup->rts_active) 732 set_rts(tup, false); 733 734 tegra_uart_rx_buffer_push(tup, 0); 735 tegra_uart_start_rx_dma(tup); 736 737 /* Activate flow control to start transfer */ 738 if (tup->rts_active) 739 set_rts(tup, true); 740 741 done: 742 spin_unlock_irqrestore(&u->lock, flags); 743 } 744 745 static void tegra_uart_handle_rx_dma(struct tegra_uart_port *tup) 746 { 747 struct dma_tx_state state; 748 749 /* Deactivate flow control to stop sender */ 750 if (tup->rts_active) 751 set_rts(tup, false); 752 753 dmaengine_terminate_all(tup->rx_dma_chan); 754 dmaengine_tx_status(tup->rx_dma_chan, tup->rx_cookie, &state); 755 tegra_uart_rx_buffer_push(tup, state.residue); 756 tegra_uart_start_rx_dma(tup); 757 758 if (tup->rts_active) 759 set_rts(tup, true); 760 } 761 762 static int tegra_uart_start_rx_dma(struct tegra_uart_port *tup) 763 { 764 unsigned int count = TEGRA_UART_RX_DMA_BUFFER_SIZE; 765 766 tup->rx_dma_desc = dmaengine_prep_slave_single(tup->rx_dma_chan, 767 tup->rx_dma_buf_phys, count, DMA_DEV_TO_MEM, 768 DMA_PREP_INTERRUPT); 769 if (!tup->rx_dma_desc) { 770 dev_err(tup->uport.dev, "Not able to get desc for Rx\n"); 771 return -EIO; 772 } 773 774 tup->rx_dma_desc->callback = tegra_uart_rx_dma_complete; 775 tup->rx_dma_desc->callback_param = tup; 776 dma_sync_single_for_device(tup->uport.dev, tup->rx_dma_buf_phys, 777 count, DMA_TO_DEVICE); 778 tup->rx_bytes_requested = count; 779 tup->rx_cookie = dmaengine_submit(tup->rx_dma_desc); 780 dma_async_issue_pending(tup->rx_dma_chan); 781 return 0; 782 } 783 784 static void tegra_uart_handle_modem_signal_change(struct uart_port *u) 785 { 786 struct tegra_uart_port *tup = to_tegra_uport(u); 787 unsigned long msr; 788 789 msr = tegra_uart_read(tup, UART_MSR); 790 if (!(msr & UART_MSR_ANY_DELTA)) 791 return; 792 793 if (msr & UART_MSR_TERI) 794 tup->uport.icount.rng++; 795 if (msr & UART_MSR_DDSR) 796 tup->uport.icount.dsr++; 797 /* We may only get DDCD when HW init and reset */ 798 if (msr & UART_MSR_DDCD) 799 uart_handle_dcd_change(&tup->uport, msr & UART_MSR_DCD); 800 /* Will start/stop_tx accordingly */ 801 if (msr & UART_MSR_DCTS) 802 uart_handle_cts_change(&tup->uport, msr & UART_MSR_CTS); 803 } 804 805 static void do_handle_rx_pio(struct tegra_uart_port *tup) 806 { 807 struct tty_struct *tty = tty_port_tty_get(&tup->uport.state->port); 808 struct tty_port *port = &tup->uport.state->port; 809 810 tegra_uart_handle_rx_pio(tup, port); 811 if (tty) { 812 tty_flip_buffer_push(port); 813 tty_kref_put(tty); 814 } 815 } 816 817 static irqreturn_t tegra_uart_isr(int irq, void *data) 818 { 819 struct tegra_uart_port *tup = data; 820 struct uart_port *u = &tup->uport; 821 unsigned long iir; 822 unsigned long ier; 823 bool is_rx_int = false; 824 unsigned long flags; 825 826 spin_lock_irqsave(&u->lock, flags); 827 while (1) { 828 iir = tegra_uart_read(tup, UART_IIR); 829 if (iir & UART_IIR_NO_INT) { 830 if (!tup->use_rx_pio && is_rx_int) { 831 tegra_uart_handle_rx_dma(tup); 832 if (tup->rx_in_progress) { 833 ier = tup->ier_shadow; 834 ier |= (UART_IER_RLSI | UART_IER_RTOIE | 835 TEGRA_UART_IER_EORD); 836 tup->ier_shadow = ier; 837 tegra_uart_write(tup, ier, UART_IER); 838 } 839 } 840 spin_unlock_irqrestore(&u->lock, flags); 841 return IRQ_HANDLED; 842 } 843 844 switch ((iir >> 1) & 0x7) { 845 case 0: /* Modem signal change interrupt */ 846 tegra_uart_handle_modem_signal_change(u); 847 break; 848 849 case 1: /* Transmit interrupt only triggered when using PIO */ 850 tup->ier_shadow &= ~UART_IER_THRI; 851 tegra_uart_write(tup, tup->ier_shadow, UART_IER); 852 tegra_uart_handle_tx_pio(tup); 853 break; 854 855 case 4: /* End of data */ 856 case 6: /* Rx timeout */ 857 case 2: /* Receive */ 858 if (!tup->use_rx_pio && !is_rx_int) { 859 is_rx_int = true; 860 /* Disable Rx interrupts */ 861 ier = tup->ier_shadow; 862 ier |= UART_IER_RDI; 863 tegra_uart_write(tup, ier, UART_IER); 864 ier &= ~(UART_IER_RDI | UART_IER_RLSI | 865 UART_IER_RTOIE | TEGRA_UART_IER_EORD); 866 tup->ier_shadow = ier; 867 tegra_uart_write(tup, ier, UART_IER); 868 } else { 869 do_handle_rx_pio(tup); 870 } 871 break; 872 873 case 3: /* Receive error */ 874 tegra_uart_decode_rx_error(tup, 875 tegra_uart_read(tup, UART_LSR)); 876 break; 877 878 case 5: /* break nothing to handle */ 879 case 7: /* break nothing to handle */ 880 break; 881 } 882 } 883 } 884 885 static void tegra_uart_stop_rx(struct uart_port *u) 886 { 887 struct tegra_uart_port *tup = to_tegra_uport(u); 888 struct tty_port *port = &tup->uport.state->port; 889 struct dma_tx_state state; 890 unsigned long ier; 891 892 if (tup->rts_active) 893 set_rts(tup, false); 894 895 if (!tup->rx_in_progress) 896 return; 897 898 tegra_uart_wait_sym_time(tup, 1); /* wait one character interval */ 899 900 ier = tup->ier_shadow; 901 ier &= ~(UART_IER_RDI | UART_IER_RLSI | UART_IER_RTOIE | 902 TEGRA_UART_IER_EORD); 903 tup->ier_shadow = ier; 904 tegra_uart_write(tup, ier, UART_IER); 905 tup->rx_in_progress = 0; 906 if (tup->rx_dma_chan && !tup->use_rx_pio) { 907 dmaengine_terminate_all(tup->rx_dma_chan); 908 dmaengine_tx_status(tup->rx_dma_chan, tup->rx_cookie, &state); 909 tegra_uart_rx_buffer_push(tup, state.residue); 910 } else { 911 tegra_uart_handle_rx_pio(tup, port); 912 } 913 } 914 915 static void tegra_uart_hw_deinit(struct tegra_uart_port *tup) 916 { 917 unsigned long flags; 918 unsigned long char_time = DIV_ROUND_UP(10000000, tup->current_baud); 919 unsigned long fifo_empty_time = tup->uport.fifosize * char_time; 920 unsigned long wait_time; 921 unsigned long lsr; 922 unsigned long msr; 923 unsigned long mcr; 924 925 /* Disable interrupts */ 926 tegra_uart_write(tup, 0, UART_IER); 927 928 lsr = tegra_uart_read(tup, UART_LSR); 929 if ((lsr & UART_LSR_TEMT) != UART_LSR_TEMT) { 930 msr = tegra_uart_read(tup, UART_MSR); 931 mcr = tegra_uart_read(tup, UART_MCR); 932 if ((mcr & TEGRA_UART_MCR_CTS_EN) && (msr & UART_MSR_CTS)) 933 dev_err(tup->uport.dev, 934 "Tx Fifo not empty, CTS disabled, waiting\n"); 935 936 /* Wait for Tx fifo to be empty */ 937 while ((lsr & UART_LSR_TEMT) != UART_LSR_TEMT) { 938 wait_time = min(fifo_empty_time, 100lu); 939 udelay(wait_time); 940 fifo_empty_time -= wait_time; 941 if (!fifo_empty_time) { 942 msr = tegra_uart_read(tup, UART_MSR); 943 mcr = tegra_uart_read(tup, UART_MCR); 944 if ((mcr & TEGRA_UART_MCR_CTS_EN) && 945 (msr & UART_MSR_CTS)) 946 dev_err(tup->uport.dev, 947 "Slave not ready\n"); 948 break; 949 } 950 lsr = tegra_uart_read(tup, UART_LSR); 951 } 952 } 953 954 spin_lock_irqsave(&tup->uport.lock, flags); 955 /* Reset the Rx and Tx FIFOs */ 956 tegra_uart_fifo_reset(tup, UART_FCR_CLEAR_XMIT | UART_FCR_CLEAR_RCVR); 957 tup->current_baud = 0; 958 spin_unlock_irqrestore(&tup->uport.lock, flags); 959 960 tup->rx_in_progress = 0; 961 tup->tx_in_progress = 0; 962 963 if (!tup->use_rx_pio) 964 tegra_uart_dma_channel_free(tup, true); 965 if (!tup->use_tx_pio) 966 tegra_uart_dma_channel_free(tup, false); 967 968 clk_disable_unprepare(tup->uart_clk); 969 } 970 971 static int tegra_uart_hw_init(struct tegra_uart_port *tup) 972 { 973 int ret; 974 975 tup->fcr_shadow = 0; 976 tup->mcr_shadow = 0; 977 tup->lcr_shadow = 0; 978 tup->ier_shadow = 0; 979 tup->current_baud = 0; 980 981 clk_prepare_enable(tup->uart_clk); 982 983 /* Reset the UART controller to clear all previous status.*/ 984 reset_control_assert(tup->rst); 985 udelay(10); 986 reset_control_deassert(tup->rst); 987 988 tup->rx_in_progress = 0; 989 tup->tx_in_progress = 0; 990 991 /* 992 * Set the trigger level 993 * 994 * For PIO mode: 995 * 996 * For receive, this will interrupt the CPU after that many number of 997 * bytes are received, for the remaining bytes the receive timeout 998 * interrupt is received. Rx high watermark is set to 4. 999 * 1000 * For transmit, if the trasnmit interrupt is enabled, this will 1001 * interrupt the CPU when the number of entries in the FIFO reaches the 1002 * low watermark. Tx low watermark is set to 16 bytes. 1003 * 1004 * For DMA mode: 1005 * 1006 * Set the Tx trigger to 16. This should match the DMA burst size that 1007 * programmed in the DMA registers. 1008 */ 1009 tup->fcr_shadow = UART_FCR_ENABLE_FIFO; 1010 1011 if (tup->use_rx_pio) { 1012 tup->fcr_shadow |= UART_FCR_R_TRIG_11; 1013 } else { 1014 if (tup->cdata->max_dma_burst_bytes == 8) 1015 tup->fcr_shadow |= UART_FCR_R_TRIG_10; 1016 else 1017 tup->fcr_shadow |= UART_FCR_R_TRIG_01; 1018 } 1019 1020 tup->fcr_shadow |= TEGRA_UART_TX_TRIG_16B; 1021 tegra_uart_write(tup, tup->fcr_shadow, UART_FCR); 1022 1023 /* Dummy read to ensure the write is posted */ 1024 tegra_uart_read(tup, UART_SCR); 1025 1026 if (tup->cdata->fifo_mode_enable_status) { 1027 ret = tegra_uart_wait_fifo_mode_enabled(tup); 1028 dev_err(tup->uport.dev, "FIFO mode not enabled\n"); 1029 if (ret < 0) 1030 return ret; 1031 } else { 1032 /* 1033 * For all tegra devices (up to t210), there is a hardware 1034 * issue that requires software to wait for 3 UART clock 1035 * periods after enabling the TX fifo, otherwise data could 1036 * be lost. 1037 */ 1038 tegra_uart_wait_cycle_time(tup, 3); 1039 } 1040 1041 /* 1042 * Initialize the UART with default configuration 1043 * (115200, N, 8, 1) so that the receive DMA buffer may be 1044 * enqueued 1045 */ 1046 ret = tegra_set_baudrate(tup, TEGRA_UART_DEFAULT_BAUD); 1047 if (ret < 0) { 1048 dev_err(tup->uport.dev, "Failed to set baud rate\n"); 1049 return ret; 1050 } 1051 if (!tup->use_rx_pio) { 1052 tup->lcr_shadow = TEGRA_UART_DEFAULT_LSR; 1053 tup->fcr_shadow |= UART_FCR_DMA_SELECT; 1054 tegra_uart_write(tup, tup->fcr_shadow, UART_FCR); 1055 1056 ret = tegra_uart_start_rx_dma(tup); 1057 if (ret < 0) { 1058 dev_err(tup->uport.dev, "Not able to start Rx DMA\n"); 1059 return ret; 1060 } 1061 } else { 1062 tegra_uart_write(tup, tup->fcr_shadow, UART_FCR); 1063 } 1064 tup->rx_in_progress = 1; 1065 1066 /* 1067 * Enable IE_RXS for the receive status interrupts like line errros. 1068 * Enable IE_RX_TIMEOUT to get the bytes which cannot be DMA'd. 1069 * 1070 * If using DMA mode, enable EORD instead of receive interrupt which 1071 * will interrupt after the UART is done with the receive instead of 1072 * the interrupt when the FIFO "threshold" is reached. 1073 * 1074 * EORD is different interrupt than RX_TIMEOUT - RX_TIMEOUT occurs when 1075 * the DATA is sitting in the FIFO and couldn't be transferred to the 1076 * DMA as the DMA size alignment (4 bytes) is not met. EORD will be 1077 * triggered when there is a pause of the incomming data stream for 4 1078 * characters long. 1079 * 1080 * For pauses in the data which is not aligned to 4 bytes, we get 1081 * both the EORD as well as RX_TIMEOUT - SW sees RX_TIMEOUT first 1082 * then the EORD. 1083 */ 1084 if (!tup->use_rx_pio) 1085 tup->ier_shadow = UART_IER_RLSI | UART_IER_RTOIE | 1086 TEGRA_UART_IER_EORD; 1087 else 1088 tup->ier_shadow = UART_IER_RLSI | UART_IER_RTOIE | UART_IER_RDI; 1089 1090 tegra_uart_write(tup, tup->ier_shadow, UART_IER); 1091 return 0; 1092 } 1093 1094 static void tegra_uart_dma_channel_free(struct tegra_uart_port *tup, 1095 bool dma_to_memory) 1096 { 1097 if (dma_to_memory) { 1098 dmaengine_terminate_all(tup->rx_dma_chan); 1099 dma_release_channel(tup->rx_dma_chan); 1100 dma_free_coherent(tup->uport.dev, TEGRA_UART_RX_DMA_BUFFER_SIZE, 1101 tup->rx_dma_buf_virt, tup->rx_dma_buf_phys); 1102 tup->rx_dma_chan = NULL; 1103 tup->rx_dma_buf_phys = 0; 1104 tup->rx_dma_buf_virt = NULL; 1105 } else { 1106 dmaengine_terminate_all(tup->tx_dma_chan); 1107 dma_release_channel(tup->tx_dma_chan); 1108 dma_unmap_single(tup->uport.dev, tup->tx_dma_buf_phys, 1109 UART_XMIT_SIZE, DMA_TO_DEVICE); 1110 tup->tx_dma_chan = NULL; 1111 tup->tx_dma_buf_phys = 0; 1112 tup->tx_dma_buf_virt = NULL; 1113 } 1114 } 1115 1116 static int tegra_uart_dma_channel_allocate(struct tegra_uart_port *tup, 1117 bool dma_to_memory) 1118 { 1119 struct dma_chan *dma_chan; 1120 unsigned char *dma_buf; 1121 dma_addr_t dma_phys; 1122 int ret; 1123 struct dma_slave_config dma_sconfig; 1124 1125 dma_chan = dma_request_chan(tup->uport.dev, dma_to_memory ? "rx" : "tx"); 1126 if (IS_ERR(dma_chan)) { 1127 ret = PTR_ERR(dma_chan); 1128 dev_err(tup->uport.dev, 1129 "DMA channel alloc failed: %d\n", ret); 1130 return ret; 1131 } 1132 1133 if (dma_to_memory) { 1134 dma_buf = dma_alloc_coherent(tup->uport.dev, 1135 TEGRA_UART_RX_DMA_BUFFER_SIZE, 1136 &dma_phys, GFP_KERNEL); 1137 if (!dma_buf) { 1138 dev_err(tup->uport.dev, 1139 "Not able to allocate the dma buffer\n"); 1140 dma_release_channel(dma_chan); 1141 return -ENOMEM; 1142 } 1143 dma_sconfig.src_addr = tup->uport.mapbase; 1144 dma_sconfig.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE; 1145 dma_sconfig.src_maxburst = tup->cdata->max_dma_burst_bytes; 1146 tup->rx_dma_chan = dma_chan; 1147 tup->rx_dma_buf_virt = dma_buf; 1148 tup->rx_dma_buf_phys = dma_phys; 1149 } else { 1150 dma_phys = dma_map_single(tup->uport.dev, 1151 tup->uport.state->xmit.buf, UART_XMIT_SIZE, 1152 DMA_TO_DEVICE); 1153 if (dma_mapping_error(tup->uport.dev, dma_phys)) { 1154 dev_err(tup->uport.dev, "dma_map_single tx failed\n"); 1155 dma_release_channel(dma_chan); 1156 return -ENOMEM; 1157 } 1158 dma_buf = tup->uport.state->xmit.buf; 1159 dma_sconfig.dst_addr = tup->uport.mapbase; 1160 dma_sconfig.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE; 1161 dma_sconfig.dst_maxburst = 16; 1162 tup->tx_dma_chan = dma_chan; 1163 tup->tx_dma_buf_virt = dma_buf; 1164 tup->tx_dma_buf_phys = dma_phys; 1165 } 1166 1167 ret = dmaengine_slave_config(dma_chan, &dma_sconfig); 1168 if (ret < 0) { 1169 dev_err(tup->uport.dev, 1170 "Dma slave config failed, err = %d\n", ret); 1171 tegra_uart_dma_channel_free(tup, dma_to_memory); 1172 return ret; 1173 } 1174 1175 return 0; 1176 } 1177 1178 static int tegra_uart_startup(struct uart_port *u) 1179 { 1180 struct tegra_uart_port *tup = to_tegra_uport(u); 1181 int ret; 1182 1183 if (!tup->use_tx_pio) { 1184 ret = tegra_uart_dma_channel_allocate(tup, false); 1185 if (ret < 0) { 1186 dev_err(u->dev, "Tx Dma allocation failed, err = %d\n", 1187 ret); 1188 return ret; 1189 } 1190 } 1191 1192 if (!tup->use_rx_pio) { 1193 ret = tegra_uart_dma_channel_allocate(tup, true); 1194 if (ret < 0) { 1195 dev_err(u->dev, "Rx Dma allocation failed, err = %d\n", 1196 ret); 1197 goto fail_rx_dma; 1198 } 1199 } 1200 1201 ret = tegra_uart_hw_init(tup); 1202 if (ret < 0) { 1203 dev_err(u->dev, "Uart HW init failed, err = %d\n", ret); 1204 goto fail_hw_init; 1205 } 1206 1207 ret = request_irq(u->irq, tegra_uart_isr, 0, 1208 dev_name(u->dev), tup); 1209 if (ret < 0) { 1210 dev_err(u->dev, "Failed to register ISR for IRQ %d\n", u->irq); 1211 goto fail_hw_init; 1212 } 1213 return 0; 1214 1215 fail_hw_init: 1216 if (!tup->use_rx_pio) 1217 tegra_uart_dma_channel_free(tup, true); 1218 fail_rx_dma: 1219 if (!tup->use_tx_pio) 1220 tegra_uart_dma_channel_free(tup, false); 1221 return ret; 1222 } 1223 1224 /* 1225 * Flush any TX data submitted for DMA and PIO. Called when the 1226 * TX circular buffer is reset. 1227 */ 1228 static void tegra_uart_flush_buffer(struct uart_port *u) 1229 { 1230 struct tegra_uart_port *tup = to_tegra_uport(u); 1231 1232 tup->tx_bytes = 0; 1233 if (tup->tx_dma_chan) 1234 dmaengine_terminate_all(tup->tx_dma_chan); 1235 } 1236 1237 static void tegra_uart_shutdown(struct uart_port *u) 1238 { 1239 struct tegra_uart_port *tup = to_tegra_uport(u); 1240 1241 tegra_uart_hw_deinit(tup); 1242 free_irq(u->irq, tup); 1243 } 1244 1245 static void tegra_uart_enable_ms(struct uart_port *u) 1246 { 1247 struct tegra_uart_port *tup = to_tegra_uport(u); 1248 1249 if (tup->enable_modem_interrupt) { 1250 tup->ier_shadow |= UART_IER_MSI; 1251 tegra_uart_write(tup, tup->ier_shadow, UART_IER); 1252 } 1253 } 1254 1255 static void tegra_uart_set_termios(struct uart_port *u, 1256 struct ktermios *termios, struct ktermios *oldtermios) 1257 { 1258 struct tegra_uart_port *tup = to_tegra_uport(u); 1259 unsigned int baud; 1260 unsigned long flags; 1261 unsigned int lcr; 1262 int symb_bit = 1; 1263 struct clk *parent_clk = clk_get_parent(tup->uart_clk); 1264 unsigned long parent_clk_rate = clk_get_rate(parent_clk); 1265 int max_divider = (tup->cdata->support_clk_src_div) ? 0x7FFF : 0xFFFF; 1266 int ret; 1267 1268 max_divider *= 16; 1269 spin_lock_irqsave(&u->lock, flags); 1270 1271 /* Changing configuration, it is safe to stop any rx now */ 1272 if (tup->rts_active) 1273 set_rts(tup, false); 1274 1275 /* Clear all interrupts as configuration is going to be changed */ 1276 tegra_uart_write(tup, tup->ier_shadow | UART_IER_RDI, UART_IER); 1277 tegra_uart_read(tup, UART_IER); 1278 tegra_uart_write(tup, 0, UART_IER); 1279 tegra_uart_read(tup, UART_IER); 1280 1281 /* Parity */ 1282 lcr = tup->lcr_shadow; 1283 lcr &= ~UART_LCR_PARITY; 1284 1285 /* CMSPAR isn't supported by this driver */ 1286 termios->c_cflag &= ~CMSPAR; 1287 1288 if ((termios->c_cflag & PARENB) == PARENB) { 1289 symb_bit++; 1290 if (termios->c_cflag & PARODD) { 1291 lcr |= UART_LCR_PARITY; 1292 lcr &= ~UART_LCR_EPAR; 1293 lcr &= ~UART_LCR_SPAR; 1294 } else { 1295 lcr |= UART_LCR_PARITY; 1296 lcr |= UART_LCR_EPAR; 1297 lcr &= ~UART_LCR_SPAR; 1298 } 1299 } 1300 1301 lcr &= ~UART_LCR_WLEN8; 1302 switch (termios->c_cflag & CSIZE) { 1303 case CS5: 1304 lcr |= UART_LCR_WLEN5; 1305 symb_bit += 5; 1306 break; 1307 case CS6: 1308 lcr |= UART_LCR_WLEN6; 1309 symb_bit += 6; 1310 break; 1311 case CS7: 1312 lcr |= UART_LCR_WLEN7; 1313 symb_bit += 7; 1314 break; 1315 default: 1316 lcr |= UART_LCR_WLEN8; 1317 symb_bit += 8; 1318 break; 1319 } 1320 1321 /* Stop bits */ 1322 if (termios->c_cflag & CSTOPB) { 1323 lcr |= UART_LCR_STOP; 1324 symb_bit += 2; 1325 } else { 1326 lcr &= ~UART_LCR_STOP; 1327 symb_bit++; 1328 } 1329 1330 tegra_uart_write(tup, lcr, UART_LCR); 1331 tup->lcr_shadow = lcr; 1332 tup->symb_bit = symb_bit; 1333 1334 /* Baud rate. */ 1335 baud = uart_get_baud_rate(u, termios, oldtermios, 1336 parent_clk_rate/max_divider, 1337 parent_clk_rate/16); 1338 spin_unlock_irqrestore(&u->lock, flags); 1339 ret = tegra_set_baudrate(tup, baud); 1340 if (ret < 0) { 1341 dev_err(tup->uport.dev, "Failed to set baud rate\n"); 1342 return; 1343 } 1344 if (tty_termios_baud_rate(termios)) 1345 tty_termios_encode_baud_rate(termios, baud, baud); 1346 spin_lock_irqsave(&u->lock, flags); 1347 1348 /* Flow control */ 1349 if (termios->c_cflag & CRTSCTS) { 1350 tup->mcr_shadow |= TEGRA_UART_MCR_CTS_EN; 1351 tup->mcr_shadow &= ~TEGRA_UART_MCR_RTS_EN; 1352 tegra_uart_write(tup, tup->mcr_shadow, UART_MCR); 1353 /* if top layer has asked to set rts active then do so here */ 1354 if (tup->rts_active) 1355 set_rts(tup, true); 1356 } else { 1357 tup->mcr_shadow &= ~TEGRA_UART_MCR_CTS_EN; 1358 tup->mcr_shadow &= ~TEGRA_UART_MCR_RTS_EN; 1359 tegra_uart_write(tup, tup->mcr_shadow, UART_MCR); 1360 } 1361 1362 /* update the port timeout based on new settings */ 1363 uart_update_timeout(u, termios->c_cflag, baud); 1364 1365 /* Make sure all writes have completed */ 1366 tegra_uart_read(tup, UART_IER); 1367 1368 /* Re-enable interrupt */ 1369 tegra_uart_write(tup, tup->ier_shadow, UART_IER); 1370 tegra_uart_read(tup, UART_IER); 1371 1372 tup->uport.ignore_status_mask = 0; 1373 /* Ignore all characters if CREAD is not set */ 1374 if ((termios->c_cflag & CREAD) == 0) 1375 tup->uport.ignore_status_mask |= UART_LSR_DR; 1376 if (termios->c_iflag & IGNBRK) 1377 tup->uport.ignore_status_mask |= UART_LSR_BI; 1378 1379 spin_unlock_irqrestore(&u->lock, flags); 1380 } 1381 1382 static const char *tegra_uart_type(struct uart_port *u) 1383 { 1384 return TEGRA_UART_TYPE; 1385 } 1386 1387 static const struct uart_ops tegra_uart_ops = { 1388 .tx_empty = tegra_uart_tx_empty, 1389 .set_mctrl = tegra_uart_set_mctrl, 1390 .get_mctrl = tegra_uart_get_mctrl, 1391 .stop_tx = tegra_uart_stop_tx, 1392 .start_tx = tegra_uart_start_tx, 1393 .stop_rx = tegra_uart_stop_rx, 1394 .flush_buffer = tegra_uart_flush_buffer, 1395 .enable_ms = tegra_uart_enable_ms, 1396 .break_ctl = tegra_uart_break_ctl, 1397 .startup = tegra_uart_startup, 1398 .shutdown = tegra_uart_shutdown, 1399 .set_termios = tegra_uart_set_termios, 1400 .type = tegra_uart_type, 1401 .request_port = tegra_uart_request_port, 1402 .release_port = tegra_uart_release_port, 1403 }; 1404 1405 static struct uart_driver tegra_uart_driver = { 1406 .owner = THIS_MODULE, 1407 .driver_name = "tegra_hsuart", 1408 .dev_name = "ttyTHS", 1409 .cons = NULL, 1410 .nr = TEGRA_UART_MAXIMUM, 1411 }; 1412 1413 static int tegra_uart_parse_dt(struct platform_device *pdev, 1414 struct tegra_uart_port *tup) 1415 { 1416 struct device_node *np = pdev->dev.of_node; 1417 int port; 1418 int ret; 1419 int index; 1420 u32 pval; 1421 int count; 1422 int n_entries; 1423 1424 port = of_alias_get_id(np, "serial"); 1425 if (port < 0) { 1426 dev_err(&pdev->dev, "failed to get alias id, errno %d\n", port); 1427 return port; 1428 } 1429 tup->uport.line = port; 1430 1431 tup->enable_modem_interrupt = of_property_read_bool(np, 1432 "nvidia,enable-modem-interrupt"); 1433 1434 index = of_property_match_string(np, "dma-names", "rx"); 1435 if (index < 0) { 1436 tup->use_rx_pio = true; 1437 dev_info(&pdev->dev, "RX in PIO mode\n"); 1438 } 1439 index = of_property_match_string(np, "dma-names", "tx"); 1440 if (index < 0) { 1441 tup->use_tx_pio = true; 1442 dev_info(&pdev->dev, "TX in PIO mode\n"); 1443 } 1444 1445 n_entries = of_property_count_u32_elems(np, "nvidia,adjust-baud-rates"); 1446 if (n_entries > 0) { 1447 tup->n_adjustable_baud_rates = n_entries / 3; 1448 tup->baud_tolerance = 1449 devm_kzalloc(&pdev->dev, (tup->n_adjustable_baud_rates) * 1450 sizeof(*tup->baud_tolerance), GFP_KERNEL); 1451 if (!tup->baud_tolerance) 1452 return -ENOMEM; 1453 for (count = 0, index = 0; count < n_entries; count += 3, 1454 index++) { 1455 ret = 1456 of_property_read_u32_index(np, 1457 "nvidia,adjust-baud-rates", 1458 count, &pval); 1459 if (!ret) 1460 tup->baud_tolerance[index].lower_range_baud = 1461 pval; 1462 ret = 1463 of_property_read_u32_index(np, 1464 "nvidia,adjust-baud-rates", 1465 count + 1, &pval); 1466 if (!ret) 1467 tup->baud_tolerance[index].upper_range_baud = 1468 pval; 1469 ret = 1470 of_property_read_u32_index(np, 1471 "nvidia,adjust-baud-rates", 1472 count + 2, &pval); 1473 if (!ret) 1474 tup->baud_tolerance[index].tolerance = 1475 (s32)pval; 1476 } 1477 } else { 1478 tup->n_adjustable_baud_rates = 0; 1479 } 1480 1481 return 0; 1482 } 1483 1484 static struct tegra_uart_chip_data tegra20_uart_chip_data = { 1485 .tx_fifo_full_status = false, 1486 .allow_txfifo_reset_fifo_mode = true, 1487 .support_clk_src_div = false, 1488 .fifo_mode_enable_status = false, 1489 .uart_max_port = 5, 1490 .max_dma_burst_bytes = 4, 1491 .error_tolerance_low_range = 0, 1492 .error_tolerance_high_range = 4, 1493 }; 1494 1495 static struct tegra_uart_chip_data tegra30_uart_chip_data = { 1496 .tx_fifo_full_status = true, 1497 .allow_txfifo_reset_fifo_mode = false, 1498 .support_clk_src_div = true, 1499 .fifo_mode_enable_status = false, 1500 .uart_max_port = 5, 1501 .max_dma_burst_bytes = 4, 1502 .error_tolerance_low_range = 0, 1503 .error_tolerance_high_range = 4, 1504 }; 1505 1506 static struct tegra_uart_chip_data tegra186_uart_chip_data = { 1507 .tx_fifo_full_status = true, 1508 .allow_txfifo_reset_fifo_mode = false, 1509 .support_clk_src_div = true, 1510 .fifo_mode_enable_status = true, 1511 .uart_max_port = 8, 1512 .max_dma_burst_bytes = 8, 1513 .error_tolerance_low_range = 0, 1514 .error_tolerance_high_range = 4, 1515 }; 1516 1517 static struct tegra_uart_chip_data tegra194_uart_chip_data = { 1518 .tx_fifo_full_status = true, 1519 .allow_txfifo_reset_fifo_mode = false, 1520 .support_clk_src_div = true, 1521 .fifo_mode_enable_status = true, 1522 .uart_max_port = 8, 1523 .max_dma_burst_bytes = 8, 1524 .error_tolerance_low_range = -2, 1525 .error_tolerance_high_range = 2, 1526 }; 1527 1528 static const struct of_device_id tegra_uart_of_match[] = { 1529 { 1530 .compatible = "nvidia,tegra30-hsuart", 1531 .data = &tegra30_uart_chip_data, 1532 }, { 1533 .compatible = "nvidia,tegra20-hsuart", 1534 .data = &tegra20_uart_chip_data, 1535 }, { 1536 .compatible = "nvidia,tegra186-hsuart", 1537 .data = &tegra186_uart_chip_data, 1538 }, { 1539 .compatible = "nvidia,tegra194-hsuart", 1540 .data = &tegra194_uart_chip_data, 1541 }, { 1542 }, 1543 }; 1544 MODULE_DEVICE_TABLE(of, tegra_uart_of_match); 1545 1546 static int tegra_uart_probe(struct platform_device *pdev) 1547 { 1548 struct tegra_uart_port *tup; 1549 struct uart_port *u; 1550 struct resource *resource; 1551 int ret; 1552 const struct tegra_uart_chip_data *cdata; 1553 const struct of_device_id *match; 1554 1555 match = of_match_device(tegra_uart_of_match, &pdev->dev); 1556 if (!match) { 1557 dev_err(&pdev->dev, "Error: No device match found\n"); 1558 return -ENODEV; 1559 } 1560 cdata = match->data; 1561 1562 tup = devm_kzalloc(&pdev->dev, sizeof(*tup), GFP_KERNEL); 1563 if (!tup) { 1564 dev_err(&pdev->dev, "Failed to allocate memory for tup\n"); 1565 return -ENOMEM; 1566 } 1567 1568 ret = tegra_uart_parse_dt(pdev, tup); 1569 if (ret < 0) 1570 return ret; 1571 1572 u = &tup->uport; 1573 u->dev = &pdev->dev; 1574 u->ops = &tegra_uart_ops; 1575 u->type = PORT_TEGRA; 1576 u->fifosize = 32; 1577 tup->cdata = cdata; 1578 1579 platform_set_drvdata(pdev, tup); 1580 resource = platform_get_resource(pdev, IORESOURCE_MEM, 0); 1581 if (!resource) { 1582 dev_err(&pdev->dev, "No IO memory resource\n"); 1583 return -ENODEV; 1584 } 1585 1586 u->mapbase = resource->start; 1587 u->membase = devm_ioremap_resource(&pdev->dev, resource); 1588 if (IS_ERR(u->membase)) 1589 return PTR_ERR(u->membase); 1590 1591 tup->uart_clk = devm_clk_get(&pdev->dev, NULL); 1592 if (IS_ERR(tup->uart_clk)) { 1593 dev_err(&pdev->dev, "Couldn't get the clock\n"); 1594 return PTR_ERR(tup->uart_clk); 1595 } 1596 1597 tup->rst = devm_reset_control_get_exclusive(&pdev->dev, "serial"); 1598 if (IS_ERR(tup->rst)) { 1599 dev_err(&pdev->dev, "Couldn't get the reset\n"); 1600 return PTR_ERR(tup->rst); 1601 } 1602 1603 u->iotype = UPIO_MEM32; 1604 ret = platform_get_irq(pdev, 0); 1605 if (ret < 0) 1606 return ret; 1607 u->irq = ret; 1608 u->regshift = 2; 1609 ret = uart_add_one_port(&tegra_uart_driver, u); 1610 if (ret < 0) { 1611 dev_err(&pdev->dev, "Failed to add uart port, err %d\n", ret); 1612 return ret; 1613 } 1614 return ret; 1615 } 1616 1617 static int tegra_uart_remove(struct platform_device *pdev) 1618 { 1619 struct tegra_uart_port *tup = platform_get_drvdata(pdev); 1620 struct uart_port *u = &tup->uport; 1621 1622 uart_remove_one_port(&tegra_uart_driver, u); 1623 return 0; 1624 } 1625 1626 #ifdef CONFIG_PM_SLEEP 1627 static int tegra_uart_suspend(struct device *dev) 1628 { 1629 struct tegra_uart_port *tup = dev_get_drvdata(dev); 1630 struct uart_port *u = &tup->uport; 1631 1632 return uart_suspend_port(&tegra_uart_driver, u); 1633 } 1634 1635 static int tegra_uart_resume(struct device *dev) 1636 { 1637 struct tegra_uart_port *tup = dev_get_drvdata(dev); 1638 struct uart_port *u = &tup->uport; 1639 1640 return uart_resume_port(&tegra_uart_driver, u); 1641 } 1642 #endif 1643 1644 static const struct dev_pm_ops tegra_uart_pm_ops = { 1645 SET_SYSTEM_SLEEP_PM_OPS(tegra_uart_suspend, tegra_uart_resume) 1646 }; 1647 1648 static struct platform_driver tegra_uart_platform_driver = { 1649 .probe = tegra_uart_probe, 1650 .remove = tegra_uart_remove, 1651 .driver = { 1652 .name = "serial-tegra", 1653 .of_match_table = tegra_uart_of_match, 1654 .pm = &tegra_uart_pm_ops, 1655 }, 1656 }; 1657 1658 static int __init tegra_uart_init(void) 1659 { 1660 int ret; 1661 struct device_node *node; 1662 const struct of_device_id *match = NULL; 1663 const struct tegra_uart_chip_data *cdata = NULL; 1664 1665 node = of_find_matching_node(NULL, tegra_uart_of_match); 1666 if (node) 1667 match = of_match_node(tegra_uart_of_match, node); 1668 if (match) 1669 cdata = match->data; 1670 if (cdata) 1671 tegra_uart_driver.nr = cdata->uart_max_port; 1672 1673 ret = uart_register_driver(&tegra_uart_driver); 1674 if (ret < 0) { 1675 pr_err("Could not register %s driver\n", 1676 tegra_uart_driver.driver_name); 1677 return ret; 1678 } 1679 1680 ret = platform_driver_register(&tegra_uart_platform_driver); 1681 if (ret < 0) { 1682 pr_err("Uart platform driver register failed, e = %d\n", ret); 1683 uart_unregister_driver(&tegra_uart_driver); 1684 return ret; 1685 } 1686 return 0; 1687 } 1688 1689 static void __exit tegra_uart_exit(void) 1690 { 1691 pr_info("Unloading tegra uart driver\n"); 1692 platform_driver_unregister(&tegra_uart_platform_driver); 1693 uart_unregister_driver(&tegra_uart_driver); 1694 } 1695 1696 module_init(tegra_uart_init); 1697 module_exit(tegra_uart_exit); 1698 1699 MODULE_ALIAS("platform:serial-tegra"); 1700 MODULE_DESCRIPTION("High speed UART driver for tegra chipset"); 1701 MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>"); 1702 MODULE_LICENSE("GPL v2"); 1703