1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * 8250-core based driver for the OMAP internal UART 4 * 5 * based on omap-serial.c, Copyright (C) 2010 Texas Instruments. 6 * 7 * Copyright (C) 2014 Sebastian Andrzej Siewior 8 * 9 */ 10 11 #if defined(CONFIG_SERIAL_8250_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ) 12 #define SUPPORT_SYSRQ 13 #endif 14 15 #include <linux/clk.h> 16 #include <linux/device.h> 17 #include <linux/io.h> 18 #include <linux/module.h> 19 #include <linux/serial_8250.h> 20 #include <linux/serial_reg.h> 21 #include <linux/tty_flip.h> 22 #include <linux/platform_device.h> 23 #include <linux/slab.h> 24 #include <linux/of.h> 25 #include <linux/of_device.h> 26 #include <linux/of_gpio.h> 27 #include <linux/of_irq.h> 28 #include <linux/delay.h> 29 #include <linux/pm_runtime.h> 30 #include <linux/console.h> 31 #include <linux/pm_qos.h> 32 #include <linux/pm_wakeirq.h> 33 #include <linux/dma-mapping.h> 34 35 #include "8250.h" 36 37 #define DEFAULT_CLK_SPEED 48000000 38 39 #define UART_ERRATA_i202_MDR1_ACCESS (1 << 0) 40 #define OMAP_UART_WER_HAS_TX_WAKEUP (1 << 1) 41 #define OMAP_DMA_TX_KICK (1 << 2) 42 /* 43 * See Advisory 21 in AM437x errata SPRZ408B, updated April 2015. 44 * The same errata is applicable to AM335x and DRA7x processors too. 45 */ 46 #define UART_ERRATA_CLOCK_DISABLE (1 << 3) 47 48 #define OMAP_UART_FCR_RX_TRIG 6 49 #define OMAP_UART_FCR_TX_TRIG 4 50 51 /* SCR register bitmasks */ 52 #define OMAP_UART_SCR_RX_TRIG_GRANU1_MASK (1 << 7) 53 #define OMAP_UART_SCR_TX_TRIG_GRANU1_MASK (1 << 6) 54 #define OMAP_UART_SCR_TX_EMPTY (1 << 3) 55 #define OMAP_UART_SCR_DMAMODE_MASK (3 << 1) 56 #define OMAP_UART_SCR_DMAMODE_1 (1 << 1) 57 #define OMAP_UART_SCR_DMAMODE_CTL (1 << 0) 58 59 /* MVR register bitmasks */ 60 #define OMAP_UART_MVR_SCHEME_SHIFT 30 61 #define OMAP_UART_LEGACY_MVR_MAJ_MASK 0xf0 62 #define OMAP_UART_LEGACY_MVR_MAJ_SHIFT 4 63 #define OMAP_UART_LEGACY_MVR_MIN_MASK 0x0f 64 #define OMAP_UART_MVR_MAJ_MASK 0x700 65 #define OMAP_UART_MVR_MAJ_SHIFT 8 66 #define OMAP_UART_MVR_MIN_MASK 0x3f 67 68 /* SYSC register bitmasks */ 69 #define OMAP_UART_SYSC_SOFTRESET (1 << 1) 70 71 /* SYSS register bitmasks */ 72 #define OMAP_UART_SYSS_RESETDONE (1 << 0) 73 74 #define UART_TI752_TLR_TX 0 75 #define UART_TI752_TLR_RX 4 76 77 #define TRIGGER_TLR_MASK(x) ((x & 0x3c) >> 2) 78 #define TRIGGER_FCR_MASK(x) (x & 3) 79 80 /* Enable XON/XOFF flow control on output */ 81 #define OMAP_UART_SW_TX 0x08 82 /* Enable XON/XOFF flow control on input */ 83 #define OMAP_UART_SW_RX 0x02 84 85 #define OMAP_UART_WER_MOD_WKUP 0x7f 86 #define OMAP_UART_TX_WAKEUP_EN (1 << 7) 87 88 #define TX_TRIGGER 1 89 #define RX_TRIGGER 48 90 91 #define OMAP_UART_TCR_RESTORE(x) ((x / 4) << 4) 92 #define OMAP_UART_TCR_HALT(x) ((x / 4) << 0) 93 94 #define UART_BUILD_REVISION(x, y) (((x) << 8) | (y)) 95 96 #define OMAP_UART_REV_46 0x0406 97 #define OMAP_UART_REV_52 0x0502 98 #define OMAP_UART_REV_63 0x0603 99 100 struct omap8250_priv { 101 int line; 102 u8 habit; 103 u8 mdr1; 104 u8 efr; 105 u8 scr; 106 u8 wer; 107 u8 xon; 108 u8 xoff; 109 u8 delayed_restore; 110 u16 quot; 111 112 bool is_suspending; 113 int wakeirq; 114 int wakeups_enabled; 115 u32 latency; 116 u32 calc_latency; 117 struct pm_qos_request pm_qos_request; 118 struct work_struct qos_work; 119 struct uart_8250_dma omap8250_dma; 120 spinlock_t rx_dma_lock; 121 bool rx_dma_broken; 122 bool throttled; 123 }; 124 125 #ifdef CONFIG_SERIAL_8250_DMA 126 static void omap_8250_rx_dma_flush(struct uart_8250_port *p); 127 #else 128 static inline void omap_8250_rx_dma_flush(struct uart_8250_port *p) { } 129 #endif 130 131 static u32 uart_read(struct uart_8250_port *up, u32 reg) 132 { 133 return readl(up->port.membase + (reg << up->port.regshift)); 134 } 135 136 static void omap8250_set_mctrl(struct uart_port *port, unsigned int mctrl) 137 { 138 struct uart_8250_port *up = up_to_u8250p(port); 139 struct omap8250_priv *priv = up->port.private_data; 140 u8 lcr; 141 142 serial8250_do_set_mctrl(port, mctrl); 143 144 if (!up->gpios) { 145 /* 146 * Turn off autoRTS if RTS is lowered and restore autoRTS 147 * setting if RTS is raised 148 */ 149 lcr = serial_in(up, UART_LCR); 150 serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B); 151 if ((mctrl & TIOCM_RTS) && (port->status & UPSTAT_AUTORTS)) 152 priv->efr |= UART_EFR_RTS; 153 else 154 priv->efr &= ~UART_EFR_RTS; 155 serial_out(up, UART_EFR, priv->efr); 156 serial_out(up, UART_LCR, lcr); 157 } 158 } 159 160 /* 161 * Work Around for Errata i202 (2430, 3430, 3630, 4430 and 4460) 162 * The access to uart register after MDR1 Access 163 * causes UART to corrupt data. 164 * 165 * Need a delay = 166 * 5 L4 clock cycles + 5 UART functional clock cycle (@48MHz = ~0.2uS) 167 * give 10 times as much 168 */ 169 static void omap_8250_mdr1_errataset(struct uart_8250_port *up, 170 struct omap8250_priv *priv) 171 { 172 u8 timeout = 255; 173 u8 old_mdr1; 174 175 old_mdr1 = serial_in(up, UART_OMAP_MDR1); 176 if (old_mdr1 == priv->mdr1) 177 return; 178 179 serial_out(up, UART_OMAP_MDR1, priv->mdr1); 180 udelay(2); 181 serial_out(up, UART_FCR, up->fcr | UART_FCR_CLEAR_XMIT | 182 UART_FCR_CLEAR_RCVR); 183 /* 184 * Wait for FIFO to empty: when empty, RX_FIFO_E bit is 0 and 185 * TX_FIFO_E bit is 1. 186 */ 187 while (UART_LSR_THRE != (serial_in(up, UART_LSR) & 188 (UART_LSR_THRE | UART_LSR_DR))) { 189 timeout--; 190 if (!timeout) { 191 /* Should *never* happen. we warn and carry on */ 192 dev_crit(up->port.dev, "Errata i202: timedout %x\n", 193 serial_in(up, UART_LSR)); 194 break; 195 } 196 udelay(1); 197 } 198 } 199 200 static void omap_8250_get_divisor(struct uart_port *port, unsigned int baud, 201 struct omap8250_priv *priv) 202 { 203 unsigned int uartclk = port->uartclk; 204 unsigned int div_13, div_16; 205 unsigned int abs_d13, abs_d16; 206 207 /* 208 * Old custom speed handling. 209 */ 210 if (baud == 38400 && (port->flags & UPF_SPD_MASK) == UPF_SPD_CUST) { 211 priv->quot = port->custom_divisor & UART_DIV_MAX; 212 /* 213 * I assume that nobody is using this. But hey, if somebody 214 * would like to specify the divisor _and_ the mode then the 215 * driver is ready and waiting for it. 216 */ 217 if (port->custom_divisor & (1 << 16)) 218 priv->mdr1 = UART_OMAP_MDR1_13X_MODE; 219 else 220 priv->mdr1 = UART_OMAP_MDR1_16X_MODE; 221 return; 222 } 223 div_13 = DIV_ROUND_CLOSEST(uartclk, 13 * baud); 224 div_16 = DIV_ROUND_CLOSEST(uartclk, 16 * baud); 225 226 if (!div_13) 227 div_13 = 1; 228 if (!div_16) 229 div_16 = 1; 230 231 abs_d13 = abs(baud - uartclk / 13 / div_13); 232 abs_d16 = abs(baud - uartclk / 16 / div_16); 233 234 if (abs_d13 >= abs_d16) { 235 priv->mdr1 = UART_OMAP_MDR1_16X_MODE; 236 priv->quot = div_16; 237 } else { 238 priv->mdr1 = UART_OMAP_MDR1_13X_MODE; 239 priv->quot = div_13; 240 } 241 } 242 243 static void omap8250_update_scr(struct uart_8250_port *up, 244 struct omap8250_priv *priv) 245 { 246 u8 old_scr; 247 248 old_scr = serial_in(up, UART_OMAP_SCR); 249 if (old_scr == priv->scr) 250 return; 251 252 /* 253 * The manual recommends not to enable the DMA mode selector in the SCR 254 * (instead of the FCR) register _and_ selecting the DMA mode as one 255 * register write because this may lead to malfunction. 256 */ 257 if (priv->scr & OMAP_UART_SCR_DMAMODE_MASK) 258 serial_out(up, UART_OMAP_SCR, 259 priv->scr & ~OMAP_UART_SCR_DMAMODE_MASK); 260 serial_out(up, UART_OMAP_SCR, priv->scr); 261 } 262 263 static void omap8250_update_mdr1(struct uart_8250_port *up, 264 struct omap8250_priv *priv) 265 { 266 if (priv->habit & UART_ERRATA_i202_MDR1_ACCESS) 267 omap_8250_mdr1_errataset(up, priv); 268 else 269 serial_out(up, UART_OMAP_MDR1, priv->mdr1); 270 } 271 272 static void omap8250_restore_regs(struct uart_8250_port *up) 273 { 274 struct omap8250_priv *priv = up->port.private_data; 275 struct uart_8250_dma *dma = up->dma; 276 277 if (dma && dma->tx_running) { 278 /* 279 * TCSANOW requests the change to occur immediately however if 280 * we have a TX-DMA operation in progress then it has been 281 * observed that it might stall and never complete. Therefore we 282 * delay DMA completes to prevent this hang from happen. 283 */ 284 priv->delayed_restore = 1; 285 return; 286 } 287 288 serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B); 289 serial_out(up, UART_EFR, UART_EFR_ECB); 290 291 serial_out(up, UART_LCR, UART_LCR_CONF_MODE_A); 292 serial8250_out_MCR(up, UART_MCR_TCRTLR); 293 serial_out(up, UART_FCR, up->fcr); 294 295 omap8250_update_scr(up, priv); 296 297 serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B); 298 299 serial_out(up, UART_TI752_TCR, OMAP_UART_TCR_RESTORE(16) | 300 OMAP_UART_TCR_HALT(52)); 301 serial_out(up, UART_TI752_TLR, 302 TRIGGER_TLR_MASK(TX_TRIGGER) << UART_TI752_TLR_TX | 303 TRIGGER_TLR_MASK(RX_TRIGGER) << UART_TI752_TLR_RX); 304 305 serial_out(up, UART_LCR, 0); 306 307 /* drop TCR + TLR access, we setup XON/XOFF later */ 308 serial8250_out_MCR(up, up->mcr); 309 serial_out(up, UART_IER, up->ier); 310 311 serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B); 312 serial_dl_write(up, priv->quot); 313 314 serial_out(up, UART_EFR, priv->efr); 315 316 /* Configure flow control */ 317 serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B); 318 serial_out(up, UART_XON1, priv->xon); 319 serial_out(up, UART_XOFF1, priv->xoff); 320 321 serial_out(up, UART_LCR, up->lcr); 322 323 omap8250_update_mdr1(up, priv); 324 325 up->port.ops->set_mctrl(&up->port, up->port.mctrl); 326 } 327 328 /* 329 * OMAP can use "CLK / (16 or 13) / div" for baud rate. And then we have have 330 * some differences in how we want to handle flow control. 331 */ 332 static void omap_8250_set_termios(struct uart_port *port, 333 struct ktermios *termios, 334 struct ktermios *old) 335 { 336 struct uart_8250_port *up = up_to_u8250p(port); 337 struct omap8250_priv *priv = up->port.private_data; 338 unsigned char cval = 0; 339 unsigned int baud; 340 341 switch (termios->c_cflag & CSIZE) { 342 case CS5: 343 cval = UART_LCR_WLEN5; 344 break; 345 case CS6: 346 cval = UART_LCR_WLEN6; 347 break; 348 case CS7: 349 cval = UART_LCR_WLEN7; 350 break; 351 default: 352 case CS8: 353 cval = UART_LCR_WLEN8; 354 break; 355 } 356 357 if (termios->c_cflag & CSTOPB) 358 cval |= UART_LCR_STOP; 359 if (termios->c_cflag & PARENB) 360 cval |= UART_LCR_PARITY; 361 if (!(termios->c_cflag & PARODD)) 362 cval |= UART_LCR_EPAR; 363 if (termios->c_cflag & CMSPAR) 364 cval |= UART_LCR_SPAR; 365 366 /* 367 * Ask the core to calculate the divisor for us. 368 */ 369 baud = uart_get_baud_rate(port, termios, old, 370 port->uartclk / 16 / UART_DIV_MAX, 371 port->uartclk / 13); 372 omap_8250_get_divisor(port, baud, priv); 373 374 /* 375 * Ok, we're now changing the port state. Do it with 376 * interrupts disabled. 377 */ 378 pm_runtime_get_sync(port->dev); 379 spin_lock_irq(&port->lock); 380 381 /* 382 * Update the per-port timeout. 383 */ 384 uart_update_timeout(port, termios->c_cflag, baud); 385 386 up->port.read_status_mask = UART_LSR_OE | UART_LSR_THRE | UART_LSR_DR; 387 if (termios->c_iflag & INPCK) 388 up->port.read_status_mask |= UART_LSR_FE | UART_LSR_PE; 389 if (termios->c_iflag & (IGNBRK | PARMRK)) 390 up->port.read_status_mask |= UART_LSR_BI; 391 392 /* 393 * Characters to ignore 394 */ 395 up->port.ignore_status_mask = 0; 396 if (termios->c_iflag & IGNPAR) 397 up->port.ignore_status_mask |= UART_LSR_PE | UART_LSR_FE; 398 if (termios->c_iflag & IGNBRK) { 399 up->port.ignore_status_mask |= UART_LSR_BI; 400 /* 401 * If we're ignoring parity and break indicators, 402 * ignore overruns too (for real raw support). 403 */ 404 if (termios->c_iflag & IGNPAR) 405 up->port.ignore_status_mask |= UART_LSR_OE; 406 } 407 408 /* 409 * ignore all characters if CREAD is not set 410 */ 411 if ((termios->c_cflag & CREAD) == 0) 412 up->port.ignore_status_mask |= UART_LSR_DR; 413 414 /* 415 * Modem status interrupts 416 */ 417 up->ier &= ~UART_IER_MSI; 418 if (UART_ENABLE_MS(&up->port, termios->c_cflag)) 419 up->ier |= UART_IER_MSI; 420 421 up->lcr = cval; 422 /* Up to here it was mostly serial8250_do_set_termios() */ 423 424 /* 425 * We enable TRIG_GRANU for RX and TX and additionally we set 426 * SCR_TX_EMPTY bit. The result is the following: 427 * - RX_TRIGGER amount of bytes in the FIFO will cause an interrupt. 428 * - less than RX_TRIGGER number of bytes will also cause an interrupt 429 * once the UART decides that there no new bytes arriving. 430 * - Once THRE is enabled, the interrupt will be fired once the FIFO is 431 * empty - the trigger level is ignored here. 432 * 433 * Once DMA is enabled: 434 * - UART will assert the TX DMA line once there is room for TX_TRIGGER 435 * bytes in the TX FIFO. On each assert the DMA engine will move 436 * TX_TRIGGER bytes into the FIFO. 437 * - UART will assert the RX DMA line once there are RX_TRIGGER bytes in 438 * the FIFO and move RX_TRIGGER bytes. 439 * This is because threshold and trigger values are the same. 440 */ 441 up->fcr = UART_FCR_ENABLE_FIFO; 442 up->fcr |= TRIGGER_FCR_MASK(TX_TRIGGER) << OMAP_UART_FCR_TX_TRIG; 443 up->fcr |= TRIGGER_FCR_MASK(RX_TRIGGER) << OMAP_UART_FCR_RX_TRIG; 444 445 priv->scr = OMAP_UART_SCR_RX_TRIG_GRANU1_MASK | OMAP_UART_SCR_TX_EMPTY | 446 OMAP_UART_SCR_TX_TRIG_GRANU1_MASK; 447 448 if (up->dma) 449 priv->scr |= OMAP_UART_SCR_DMAMODE_1 | 450 OMAP_UART_SCR_DMAMODE_CTL; 451 452 priv->xon = termios->c_cc[VSTART]; 453 priv->xoff = termios->c_cc[VSTOP]; 454 455 priv->efr = 0; 456 up->port.status &= ~(UPSTAT_AUTOCTS | UPSTAT_AUTORTS | UPSTAT_AUTOXOFF); 457 458 if (termios->c_cflag & CRTSCTS && up->port.flags & UPF_HARD_FLOW && 459 !up->gpios) { 460 /* Enable AUTOCTS (autoRTS is enabled when RTS is raised) */ 461 up->port.status |= UPSTAT_AUTOCTS | UPSTAT_AUTORTS; 462 priv->efr |= UART_EFR_CTS; 463 } else if (up->port.flags & UPF_SOFT_FLOW) { 464 /* 465 * OMAP rx s/w flow control is borked; the transmitter remains 466 * stuck off even if rx flow control is subsequently disabled 467 */ 468 469 /* 470 * IXOFF Flag: 471 * Enable XON/XOFF flow control on output. 472 * Transmit XON1, XOFF1 473 */ 474 if (termios->c_iflag & IXOFF) { 475 up->port.status |= UPSTAT_AUTOXOFF; 476 priv->efr |= OMAP_UART_SW_TX; 477 } 478 } 479 omap8250_restore_regs(up); 480 481 spin_unlock_irq(&up->port.lock); 482 pm_runtime_mark_last_busy(port->dev); 483 pm_runtime_put_autosuspend(port->dev); 484 485 /* calculate wakeup latency constraint */ 486 priv->calc_latency = USEC_PER_SEC * 64 * 8 / baud; 487 priv->latency = priv->calc_latency; 488 489 schedule_work(&priv->qos_work); 490 491 /* Don't rewrite B0 */ 492 if (tty_termios_baud_rate(termios)) 493 tty_termios_encode_baud_rate(termios, baud, baud); 494 } 495 496 /* same as 8250 except that we may have extra flow bits set in EFR */ 497 static void omap_8250_pm(struct uart_port *port, unsigned int state, 498 unsigned int oldstate) 499 { 500 struct uart_8250_port *up = up_to_u8250p(port); 501 u8 efr; 502 503 pm_runtime_get_sync(port->dev); 504 serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B); 505 efr = serial_in(up, UART_EFR); 506 serial_out(up, UART_EFR, efr | UART_EFR_ECB); 507 serial_out(up, UART_LCR, 0); 508 509 serial_out(up, UART_IER, (state != 0) ? UART_IERX_SLEEP : 0); 510 serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B); 511 serial_out(up, UART_EFR, efr); 512 serial_out(up, UART_LCR, 0); 513 514 pm_runtime_mark_last_busy(port->dev); 515 pm_runtime_put_autosuspend(port->dev); 516 } 517 518 static void omap_serial_fill_features_erratas(struct uart_8250_port *up, 519 struct omap8250_priv *priv) 520 { 521 u32 mvr, scheme; 522 u16 revision, major, minor; 523 524 mvr = uart_read(up, UART_OMAP_MVER); 525 526 /* Check revision register scheme */ 527 scheme = mvr >> OMAP_UART_MVR_SCHEME_SHIFT; 528 529 switch (scheme) { 530 case 0: /* Legacy Scheme: OMAP2/3 */ 531 /* MINOR_REV[0:4], MAJOR_REV[4:7] */ 532 major = (mvr & OMAP_UART_LEGACY_MVR_MAJ_MASK) >> 533 OMAP_UART_LEGACY_MVR_MAJ_SHIFT; 534 minor = (mvr & OMAP_UART_LEGACY_MVR_MIN_MASK); 535 break; 536 case 1: 537 /* New Scheme: OMAP4+ */ 538 /* MINOR_REV[0:5], MAJOR_REV[8:10] */ 539 major = (mvr & OMAP_UART_MVR_MAJ_MASK) >> 540 OMAP_UART_MVR_MAJ_SHIFT; 541 minor = (mvr & OMAP_UART_MVR_MIN_MASK); 542 break; 543 default: 544 dev_warn(up->port.dev, 545 "Unknown revision, defaulting to highest\n"); 546 /* highest possible revision */ 547 major = 0xff; 548 minor = 0xff; 549 } 550 /* normalize revision for the driver */ 551 revision = UART_BUILD_REVISION(major, minor); 552 553 switch (revision) { 554 case OMAP_UART_REV_46: 555 priv->habit |= UART_ERRATA_i202_MDR1_ACCESS; 556 break; 557 case OMAP_UART_REV_52: 558 priv->habit |= UART_ERRATA_i202_MDR1_ACCESS | 559 OMAP_UART_WER_HAS_TX_WAKEUP; 560 break; 561 case OMAP_UART_REV_63: 562 priv->habit |= UART_ERRATA_i202_MDR1_ACCESS | 563 OMAP_UART_WER_HAS_TX_WAKEUP; 564 break; 565 default: 566 break; 567 } 568 } 569 570 static void omap8250_uart_qos_work(struct work_struct *work) 571 { 572 struct omap8250_priv *priv; 573 574 priv = container_of(work, struct omap8250_priv, qos_work); 575 pm_qos_update_request(&priv->pm_qos_request, priv->latency); 576 } 577 578 #ifdef CONFIG_SERIAL_8250_DMA 579 static int omap_8250_dma_handle_irq(struct uart_port *port); 580 #endif 581 582 static irqreturn_t omap8250_irq(int irq, void *dev_id) 583 { 584 struct uart_port *port = dev_id; 585 struct uart_8250_port *up = up_to_u8250p(port); 586 unsigned int iir; 587 int ret; 588 589 #ifdef CONFIG_SERIAL_8250_DMA 590 if (up->dma) { 591 ret = omap_8250_dma_handle_irq(port); 592 return IRQ_RETVAL(ret); 593 } 594 #endif 595 596 serial8250_rpm_get(up); 597 iir = serial_port_in(port, UART_IIR); 598 ret = serial8250_handle_irq(port, iir); 599 serial8250_rpm_put(up); 600 601 return IRQ_RETVAL(ret); 602 } 603 604 static int omap_8250_startup(struct uart_port *port) 605 { 606 struct uart_8250_port *up = up_to_u8250p(port); 607 struct omap8250_priv *priv = port->private_data; 608 int ret; 609 610 if (priv->wakeirq) { 611 ret = dev_pm_set_dedicated_wake_irq(port->dev, priv->wakeirq); 612 if (ret) 613 return ret; 614 } 615 616 pm_runtime_get_sync(port->dev); 617 618 up->mcr = 0; 619 serial_out(up, UART_FCR, UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT); 620 621 serial_out(up, UART_LCR, UART_LCR_WLEN8); 622 623 up->lsr_saved_flags = 0; 624 up->msr_saved_flags = 0; 625 626 /* Disable DMA for console UART */ 627 if (uart_console(port)) 628 up->dma = NULL; 629 630 if (up->dma) { 631 ret = serial8250_request_dma(up); 632 if (ret) { 633 dev_warn_ratelimited(port->dev, 634 "failed to request DMA\n"); 635 up->dma = NULL; 636 } 637 } 638 639 ret = request_irq(port->irq, omap8250_irq, IRQF_SHARED, 640 dev_name(port->dev), port); 641 if (ret < 0) 642 goto err; 643 644 up->ier = UART_IER_RLSI | UART_IER_RDI; 645 serial_out(up, UART_IER, up->ier); 646 647 #ifdef CONFIG_PM 648 up->capabilities |= UART_CAP_RPM; 649 #endif 650 651 /* Enable module level wake up */ 652 priv->wer = OMAP_UART_WER_MOD_WKUP; 653 if (priv->habit & OMAP_UART_WER_HAS_TX_WAKEUP) 654 priv->wer |= OMAP_UART_TX_WAKEUP_EN; 655 serial_out(up, UART_OMAP_WER, priv->wer); 656 657 if (up->dma) 658 up->dma->rx_dma(up); 659 660 pm_runtime_mark_last_busy(port->dev); 661 pm_runtime_put_autosuspend(port->dev); 662 return 0; 663 err: 664 pm_runtime_mark_last_busy(port->dev); 665 pm_runtime_put_autosuspend(port->dev); 666 dev_pm_clear_wake_irq(port->dev); 667 return ret; 668 } 669 670 static void omap_8250_shutdown(struct uart_port *port) 671 { 672 struct uart_8250_port *up = up_to_u8250p(port); 673 struct omap8250_priv *priv = port->private_data; 674 675 flush_work(&priv->qos_work); 676 if (up->dma) 677 omap_8250_rx_dma_flush(up); 678 679 pm_runtime_get_sync(port->dev); 680 681 serial_out(up, UART_OMAP_WER, 0); 682 683 up->ier = 0; 684 serial_out(up, UART_IER, 0); 685 686 if (up->dma) 687 serial8250_release_dma(up); 688 689 /* 690 * Disable break condition and FIFOs 691 */ 692 if (up->lcr & UART_LCR_SBC) 693 serial_out(up, UART_LCR, up->lcr & ~UART_LCR_SBC); 694 serial_out(up, UART_FCR, UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT); 695 696 pm_runtime_mark_last_busy(port->dev); 697 pm_runtime_put_autosuspend(port->dev); 698 free_irq(port->irq, port); 699 dev_pm_clear_wake_irq(port->dev); 700 } 701 702 static void omap_8250_throttle(struct uart_port *port) 703 { 704 struct omap8250_priv *priv = port->private_data; 705 struct uart_8250_port *up = up_to_u8250p(port); 706 unsigned long flags; 707 708 pm_runtime_get_sync(port->dev); 709 710 spin_lock_irqsave(&port->lock, flags); 711 up->ier &= ~(UART_IER_RLSI | UART_IER_RDI); 712 serial_out(up, UART_IER, up->ier); 713 priv->throttled = true; 714 spin_unlock_irqrestore(&port->lock, flags); 715 716 pm_runtime_mark_last_busy(port->dev); 717 pm_runtime_put_autosuspend(port->dev); 718 } 719 720 static int omap_8250_rs485_config(struct uart_port *port, 721 struct serial_rs485 *rs485) 722 { 723 struct uart_8250_port *up = up_to_u8250p(port); 724 725 /* Clamp the delays to [0, 100ms] */ 726 rs485->delay_rts_before_send = min(rs485->delay_rts_before_send, 100U); 727 rs485->delay_rts_after_send = min(rs485->delay_rts_after_send, 100U); 728 729 port->rs485 = *rs485; 730 731 /* 732 * Both serial8250_em485_init and serial8250_em485_destroy 733 * are idempotent 734 */ 735 if (rs485->flags & SER_RS485_ENABLED) { 736 int ret = serial8250_em485_init(up); 737 738 if (ret) { 739 rs485->flags &= ~SER_RS485_ENABLED; 740 port->rs485.flags &= ~SER_RS485_ENABLED; 741 } 742 return ret; 743 } 744 745 serial8250_em485_destroy(up); 746 747 return 0; 748 } 749 750 static void omap_8250_unthrottle(struct uart_port *port) 751 { 752 struct omap8250_priv *priv = port->private_data; 753 struct uart_8250_port *up = up_to_u8250p(port); 754 unsigned long flags; 755 756 pm_runtime_get_sync(port->dev); 757 758 spin_lock_irqsave(&port->lock, flags); 759 priv->throttled = false; 760 if (up->dma) 761 up->dma->rx_dma(up); 762 up->ier |= UART_IER_RLSI | UART_IER_RDI; 763 serial_out(up, UART_IER, up->ier); 764 spin_unlock_irqrestore(&port->lock, flags); 765 766 pm_runtime_mark_last_busy(port->dev); 767 pm_runtime_put_autosuspend(port->dev); 768 } 769 770 #ifdef CONFIG_SERIAL_8250_DMA 771 static int omap_8250_rx_dma(struct uart_8250_port *p); 772 773 static void __dma_rx_do_complete(struct uart_8250_port *p) 774 { 775 struct omap8250_priv *priv = p->port.private_data; 776 struct uart_8250_dma *dma = p->dma; 777 struct tty_port *tty_port = &p->port.state->port; 778 struct dma_tx_state state; 779 int count; 780 unsigned long flags; 781 int ret; 782 783 spin_lock_irqsave(&priv->rx_dma_lock, flags); 784 785 if (!dma->rx_running) 786 goto unlock; 787 788 dma->rx_running = 0; 789 dmaengine_tx_status(dma->rxchan, dma->rx_cookie, &state); 790 791 count = dma->rx_size - state.residue; 792 793 ret = tty_insert_flip_string(tty_port, dma->rx_buf, count); 794 795 p->port.icount.rx += ret; 796 p->port.icount.buf_overrun += count - ret; 797 unlock: 798 spin_unlock_irqrestore(&priv->rx_dma_lock, flags); 799 800 tty_flip_buffer_push(tty_port); 801 } 802 803 static void __dma_rx_complete(void *param) 804 { 805 struct uart_8250_port *p = param; 806 struct omap8250_priv *priv = p->port.private_data; 807 struct uart_8250_dma *dma = p->dma; 808 struct dma_tx_state state; 809 unsigned long flags; 810 811 spin_lock_irqsave(&p->port.lock, flags); 812 813 /* 814 * If the tx status is not DMA_COMPLETE, then this is a delayed 815 * completion callback. A previous RX timeout flush would have 816 * already pushed the data, so exit. 817 */ 818 if (dmaengine_tx_status(dma->rxchan, dma->rx_cookie, &state) != 819 DMA_COMPLETE) { 820 spin_unlock_irqrestore(&p->port.lock, flags); 821 return; 822 } 823 __dma_rx_do_complete(p); 824 if (!priv->throttled) 825 omap_8250_rx_dma(p); 826 827 spin_unlock_irqrestore(&p->port.lock, flags); 828 } 829 830 static void omap_8250_rx_dma_flush(struct uart_8250_port *p) 831 { 832 struct omap8250_priv *priv = p->port.private_data; 833 struct uart_8250_dma *dma = p->dma; 834 struct dma_tx_state state; 835 unsigned long flags; 836 int ret; 837 838 spin_lock_irqsave(&priv->rx_dma_lock, flags); 839 840 if (!dma->rx_running) { 841 spin_unlock_irqrestore(&priv->rx_dma_lock, flags); 842 return; 843 } 844 845 ret = dmaengine_tx_status(dma->rxchan, dma->rx_cookie, &state); 846 if (ret == DMA_IN_PROGRESS) { 847 ret = dmaengine_pause(dma->rxchan); 848 if (WARN_ON_ONCE(ret)) 849 priv->rx_dma_broken = true; 850 } 851 spin_unlock_irqrestore(&priv->rx_dma_lock, flags); 852 853 __dma_rx_do_complete(p); 854 dmaengine_terminate_all(dma->rxchan); 855 } 856 857 static int omap_8250_rx_dma(struct uart_8250_port *p) 858 { 859 struct omap8250_priv *priv = p->port.private_data; 860 struct uart_8250_dma *dma = p->dma; 861 int err = 0; 862 struct dma_async_tx_descriptor *desc; 863 unsigned long flags; 864 865 if (priv->rx_dma_broken) 866 return -EINVAL; 867 868 spin_lock_irqsave(&priv->rx_dma_lock, flags); 869 870 if (dma->rx_running) 871 goto out; 872 873 desc = dmaengine_prep_slave_single(dma->rxchan, dma->rx_addr, 874 dma->rx_size, DMA_DEV_TO_MEM, 875 DMA_PREP_INTERRUPT | DMA_CTRL_ACK); 876 if (!desc) { 877 err = -EBUSY; 878 goto out; 879 } 880 881 dma->rx_running = 1; 882 desc->callback = __dma_rx_complete; 883 desc->callback_param = p; 884 885 dma->rx_cookie = dmaengine_submit(desc); 886 887 dma_async_issue_pending(dma->rxchan); 888 out: 889 spin_unlock_irqrestore(&priv->rx_dma_lock, flags); 890 return err; 891 } 892 893 static int omap_8250_tx_dma(struct uart_8250_port *p); 894 895 static void omap_8250_dma_tx_complete(void *param) 896 { 897 struct uart_8250_port *p = param; 898 struct uart_8250_dma *dma = p->dma; 899 struct circ_buf *xmit = &p->port.state->xmit; 900 unsigned long flags; 901 bool en_thri = false; 902 struct omap8250_priv *priv = p->port.private_data; 903 904 dma_sync_single_for_cpu(dma->txchan->device->dev, dma->tx_addr, 905 UART_XMIT_SIZE, DMA_TO_DEVICE); 906 907 spin_lock_irqsave(&p->port.lock, flags); 908 909 dma->tx_running = 0; 910 911 xmit->tail += dma->tx_size; 912 xmit->tail &= UART_XMIT_SIZE - 1; 913 p->port.icount.tx += dma->tx_size; 914 915 if (priv->delayed_restore) { 916 priv->delayed_restore = 0; 917 omap8250_restore_regs(p); 918 } 919 920 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) 921 uart_write_wakeup(&p->port); 922 923 if (!uart_circ_empty(xmit) && !uart_tx_stopped(&p->port)) { 924 int ret; 925 926 ret = omap_8250_tx_dma(p); 927 if (ret) 928 en_thri = true; 929 } else if (p->capabilities & UART_CAP_RPM) { 930 en_thri = true; 931 } 932 933 if (en_thri) { 934 dma->tx_err = 1; 935 serial8250_set_THRI(p); 936 } 937 938 spin_unlock_irqrestore(&p->port.lock, flags); 939 } 940 941 static int omap_8250_tx_dma(struct uart_8250_port *p) 942 { 943 struct uart_8250_dma *dma = p->dma; 944 struct omap8250_priv *priv = p->port.private_data; 945 struct circ_buf *xmit = &p->port.state->xmit; 946 struct dma_async_tx_descriptor *desc; 947 unsigned int skip_byte = 0; 948 int ret; 949 950 if (dma->tx_running) 951 return 0; 952 if (uart_tx_stopped(&p->port) || uart_circ_empty(xmit)) { 953 954 /* 955 * Even if no data, we need to return an error for the two cases 956 * below so serial8250_tx_chars() is invoked and properly clears 957 * THRI and/or runtime suspend. 958 */ 959 if (dma->tx_err || p->capabilities & UART_CAP_RPM) { 960 ret = -EBUSY; 961 goto err; 962 } 963 serial8250_clear_THRI(p); 964 return 0; 965 } 966 967 dma->tx_size = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE); 968 if (priv->habit & OMAP_DMA_TX_KICK) { 969 u8 tx_lvl; 970 971 /* 972 * We need to put the first byte into the FIFO in order to start 973 * the DMA transfer. For transfers smaller than four bytes we 974 * don't bother doing DMA at all. It seem not matter if there 975 * are still bytes in the FIFO from the last transfer (in case 976 * we got here directly from omap_8250_dma_tx_complete()). Bytes 977 * leaving the FIFO seem not to trigger the DMA transfer. It is 978 * really the byte that we put into the FIFO. 979 * If the FIFO is already full then we most likely got here from 980 * omap_8250_dma_tx_complete(). And this means the DMA engine 981 * just completed its work. We don't have to wait the complete 982 * 86us at 115200,8n1 but around 60us (not to mention lower 983 * baudrates). So in that case we take the interrupt and try 984 * again with an empty FIFO. 985 */ 986 tx_lvl = serial_in(p, UART_OMAP_TX_LVL); 987 if (tx_lvl == p->tx_loadsz) { 988 ret = -EBUSY; 989 goto err; 990 } 991 if (dma->tx_size < 4) { 992 ret = -EINVAL; 993 goto err; 994 } 995 skip_byte = 1; 996 } 997 998 desc = dmaengine_prep_slave_single(dma->txchan, 999 dma->tx_addr + xmit->tail + skip_byte, 1000 dma->tx_size - skip_byte, DMA_MEM_TO_DEV, 1001 DMA_PREP_INTERRUPT | DMA_CTRL_ACK); 1002 if (!desc) { 1003 ret = -EBUSY; 1004 goto err; 1005 } 1006 1007 dma->tx_running = 1; 1008 1009 desc->callback = omap_8250_dma_tx_complete; 1010 desc->callback_param = p; 1011 1012 dma->tx_cookie = dmaengine_submit(desc); 1013 1014 dma_sync_single_for_device(dma->txchan->device->dev, dma->tx_addr, 1015 UART_XMIT_SIZE, DMA_TO_DEVICE); 1016 1017 dma_async_issue_pending(dma->txchan); 1018 if (dma->tx_err) 1019 dma->tx_err = 0; 1020 1021 serial8250_clear_THRI(p); 1022 if (skip_byte) 1023 serial_out(p, UART_TX, xmit->buf[xmit->tail]); 1024 return 0; 1025 err: 1026 dma->tx_err = 1; 1027 return ret; 1028 } 1029 1030 static bool handle_rx_dma(struct uart_8250_port *up, unsigned int iir) 1031 { 1032 switch (iir & 0x3f) { 1033 case UART_IIR_RLSI: 1034 case UART_IIR_RX_TIMEOUT: 1035 case UART_IIR_RDI: 1036 omap_8250_rx_dma_flush(up); 1037 return true; 1038 } 1039 return omap_8250_rx_dma(up); 1040 } 1041 1042 /* 1043 * This is mostly serial8250_handle_irq(). We have a slightly different DMA 1044 * hoook for RX/TX and need different logic for them in the ISR. Therefore we 1045 * use the default routine in the non-DMA case and this one for with DMA. 1046 */ 1047 static int omap_8250_dma_handle_irq(struct uart_port *port) 1048 { 1049 struct uart_8250_port *up = up_to_u8250p(port); 1050 unsigned char status; 1051 unsigned long flags; 1052 u8 iir; 1053 1054 serial8250_rpm_get(up); 1055 1056 iir = serial_port_in(port, UART_IIR); 1057 if (iir & UART_IIR_NO_INT) { 1058 serial8250_rpm_put(up); 1059 return 0; 1060 } 1061 1062 spin_lock_irqsave(&port->lock, flags); 1063 1064 status = serial_port_in(port, UART_LSR); 1065 1066 if (status & (UART_LSR_DR | UART_LSR_BI)) { 1067 if (handle_rx_dma(up, iir)) { 1068 status = serial8250_rx_chars(up, status); 1069 omap_8250_rx_dma(up); 1070 } 1071 } 1072 serial8250_modem_status(up); 1073 if (status & UART_LSR_THRE && up->dma->tx_err) { 1074 if (uart_tx_stopped(&up->port) || 1075 uart_circ_empty(&up->port.state->xmit)) { 1076 up->dma->tx_err = 0; 1077 serial8250_tx_chars(up); 1078 } else { 1079 /* 1080 * try again due to an earlier failer which 1081 * might have been resolved by now. 1082 */ 1083 if (omap_8250_tx_dma(up)) 1084 serial8250_tx_chars(up); 1085 } 1086 } 1087 1088 uart_unlock_and_check_sysrq(port, flags); 1089 serial8250_rpm_put(up); 1090 return 1; 1091 } 1092 1093 static bool the_no_dma_filter_fn(struct dma_chan *chan, void *param) 1094 { 1095 return false; 1096 } 1097 1098 #else 1099 1100 static inline int omap_8250_rx_dma(struct uart_8250_port *p) 1101 { 1102 return -EINVAL; 1103 } 1104 #endif 1105 1106 static int omap8250_no_handle_irq(struct uart_port *port) 1107 { 1108 /* IRQ has not been requested but handling irq? */ 1109 WARN_ONCE(1, "Unexpected irq handling before port startup\n"); 1110 return 0; 1111 } 1112 1113 static const u8 omap4_habit = UART_ERRATA_CLOCK_DISABLE; 1114 static const u8 am3352_habit = OMAP_DMA_TX_KICK | UART_ERRATA_CLOCK_DISABLE; 1115 static const u8 dra742_habit = UART_ERRATA_CLOCK_DISABLE; 1116 1117 static const struct of_device_id omap8250_dt_ids[] = { 1118 { .compatible = "ti,am654-uart" }, 1119 { .compatible = "ti,omap2-uart" }, 1120 { .compatible = "ti,omap3-uart" }, 1121 { .compatible = "ti,omap4-uart", .data = &omap4_habit, }, 1122 { .compatible = "ti,am3352-uart", .data = &am3352_habit, }, 1123 { .compatible = "ti,am4372-uart", .data = &am3352_habit, }, 1124 { .compatible = "ti,dra742-uart", .data = &dra742_habit, }, 1125 {}, 1126 }; 1127 MODULE_DEVICE_TABLE(of, omap8250_dt_ids); 1128 1129 static int omap8250_probe(struct platform_device *pdev) 1130 { 1131 struct resource *regs = platform_get_resource(pdev, IORESOURCE_MEM, 0); 1132 struct resource *irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0); 1133 struct device_node *np = pdev->dev.of_node; 1134 struct omap8250_priv *priv; 1135 struct uart_8250_port up; 1136 int ret; 1137 void __iomem *membase; 1138 const struct of_device_id *id; 1139 1140 if (!regs || !irq) { 1141 dev_err(&pdev->dev, "missing registers or irq\n"); 1142 return -EINVAL; 1143 } 1144 1145 priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); 1146 if (!priv) 1147 return -ENOMEM; 1148 1149 membase = devm_ioremap_nocache(&pdev->dev, regs->start, 1150 resource_size(regs)); 1151 if (!membase) 1152 return -ENODEV; 1153 1154 memset(&up, 0, sizeof(up)); 1155 up.port.dev = &pdev->dev; 1156 up.port.mapbase = regs->start; 1157 up.port.membase = membase; 1158 up.port.irq = irq->start; 1159 /* 1160 * It claims to be 16C750 compatible however it is a little different. 1161 * It has EFR and has no FCR7_64byte bit. The AFE (which it claims to 1162 * have) is enabled via EFR instead of MCR. The type is set here 8250 1163 * just to get things going. UNKNOWN does not work for a few reasons and 1164 * we don't need our own type since we don't use 8250's set_termios() 1165 * or pm callback. 1166 */ 1167 up.port.type = PORT_8250; 1168 up.port.iotype = UPIO_MEM; 1169 up.port.flags = UPF_FIXED_PORT | UPF_FIXED_TYPE | UPF_SOFT_FLOW | 1170 UPF_HARD_FLOW; 1171 up.port.private_data = priv; 1172 1173 up.port.regshift = 2; 1174 up.port.fifosize = 64; 1175 up.tx_loadsz = 64; 1176 up.capabilities = UART_CAP_FIFO; 1177 #ifdef CONFIG_PM 1178 /* 1179 * Runtime PM is mostly transparent. However to do it right we need to a 1180 * TX empty interrupt before we can put the device to auto idle. So if 1181 * PM is not enabled we don't add that flag and can spare that one extra 1182 * interrupt in the TX path. 1183 */ 1184 up.capabilities |= UART_CAP_RPM; 1185 #endif 1186 up.port.set_termios = omap_8250_set_termios; 1187 up.port.set_mctrl = omap8250_set_mctrl; 1188 up.port.pm = omap_8250_pm; 1189 up.port.startup = omap_8250_startup; 1190 up.port.shutdown = omap_8250_shutdown; 1191 up.port.throttle = omap_8250_throttle; 1192 up.port.unthrottle = omap_8250_unthrottle; 1193 up.port.rs485_config = omap_8250_rs485_config; 1194 1195 ret = of_alias_get_id(np, "serial"); 1196 if (ret < 0) { 1197 dev_err(&pdev->dev, "failed to get alias\n"); 1198 return ret; 1199 } 1200 up.port.line = ret; 1201 1202 if (of_property_read_u32(np, "clock-frequency", &up.port.uartclk)) { 1203 struct clk *clk; 1204 1205 clk = devm_clk_get(&pdev->dev, NULL); 1206 if (IS_ERR(clk)) { 1207 if (PTR_ERR(clk) == -EPROBE_DEFER) 1208 return -EPROBE_DEFER; 1209 } else { 1210 up.port.uartclk = clk_get_rate(clk); 1211 } 1212 } 1213 1214 priv->wakeirq = irq_of_parse_and_map(np, 1); 1215 1216 id = of_match_device(of_match_ptr(omap8250_dt_ids), &pdev->dev); 1217 if (id && id->data) 1218 priv->habit |= *(u8 *)id->data; 1219 1220 if (!up.port.uartclk) { 1221 up.port.uartclk = DEFAULT_CLK_SPEED; 1222 dev_warn(&pdev->dev, 1223 "No clock speed specified: using default: %d\n", 1224 DEFAULT_CLK_SPEED); 1225 } 1226 1227 priv->latency = PM_QOS_CPU_DMA_LAT_DEFAULT_VALUE; 1228 priv->calc_latency = PM_QOS_CPU_DMA_LAT_DEFAULT_VALUE; 1229 pm_qos_add_request(&priv->pm_qos_request, PM_QOS_CPU_DMA_LATENCY, 1230 priv->latency); 1231 INIT_WORK(&priv->qos_work, omap8250_uart_qos_work); 1232 1233 spin_lock_init(&priv->rx_dma_lock); 1234 1235 device_init_wakeup(&pdev->dev, true); 1236 pm_runtime_use_autosuspend(&pdev->dev); 1237 1238 /* 1239 * Disable runtime PM until autosuspend delay unless specifically 1240 * enabled by the user via sysfs. This is the historic way to 1241 * prevent an unsafe default policy with lossy characters on wake-up. 1242 * For serdev devices this is not needed, the policy can be managed by 1243 * the serdev driver. 1244 */ 1245 if (!of_get_available_child_count(pdev->dev.of_node)) 1246 pm_runtime_set_autosuspend_delay(&pdev->dev, -1); 1247 1248 pm_runtime_irq_safe(&pdev->dev); 1249 pm_runtime_enable(&pdev->dev); 1250 1251 pm_runtime_get_sync(&pdev->dev); 1252 1253 omap_serial_fill_features_erratas(&up, priv); 1254 up.port.handle_irq = omap8250_no_handle_irq; 1255 #ifdef CONFIG_SERIAL_8250_DMA 1256 /* 1257 * Oh DMA support. If there are no DMA properties in the DT then 1258 * we will fall back to a generic DMA channel which does not 1259 * really work here. To ensure that we do not get a generic DMA 1260 * channel assigned, we have the the_no_dma_filter_fn() here. 1261 * To avoid "failed to request DMA" messages we check for DMA 1262 * properties in DT. 1263 */ 1264 ret = of_property_count_strings(np, "dma-names"); 1265 if (ret == 2) { 1266 up.dma = &priv->omap8250_dma; 1267 priv->omap8250_dma.fn = the_no_dma_filter_fn; 1268 priv->omap8250_dma.tx_dma = omap_8250_tx_dma; 1269 priv->omap8250_dma.rx_dma = omap_8250_rx_dma; 1270 priv->omap8250_dma.rx_size = RX_TRIGGER; 1271 priv->omap8250_dma.rxconf.src_maxburst = RX_TRIGGER; 1272 priv->omap8250_dma.txconf.dst_maxburst = TX_TRIGGER; 1273 } 1274 #endif 1275 ret = serial8250_register_8250_port(&up); 1276 if (ret < 0) { 1277 dev_err(&pdev->dev, "unable to register 8250 port\n"); 1278 goto err; 1279 } 1280 priv->line = ret; 1281 platform_set_drvdata(pdev, priv); 1282 pm_runtime_mark_last_busy(&pdev->dev); 1283 pm_runtime_put_autosuspend(&pdev->dev); 1284 return 0; 1285 err: 1286 pm_runtime_dont_use_autosuspend(&pdev->dev); 1287 pm_runtime_put_sync(&pdev->dev); 1288 pm_runtime_disable(&pdev->dev); 1289 return ret; 1290 } 1291 1292 static int omap8250_remove(struct platform_device *pdev) 1293 { 1294 struct omap8250_priv *priv = platform_get_drvdata(pdev); 1295 1296 pm_runtime_dont_use_autosuspend(&pdev->dev); 1297 pm_runtime_put_sync(&pdev->dev); 1298 pm_runtime_disable(&pdev->dev); 1299 serial8250_unregister_port(priv->line); 1300 pm_qos_remove_request(&priv->pm_qos_request); 1301 device_init_wakeup(&pdev->dev, false); 1302 return 0; 1303 } 1304 1305 #ifdef CONFIG_PM_SLEEP 1306 static int omap8250_prepare(struct device *dev) 1307 { 1308 struct omap8250_priv *priv = dev_get_drvdata(dev); 1309 1310 if (!priv) 1311 return 0; 1312 priv->is_suspending = true; 1313 return 0; 1314 } 1315 1316 static void omap8250_complete(struct device *dev) 1317 { 1318 struct omap8250_priv *priv = dev_get_drvdata(dev); 1319 1320 if (!priv) 1321 return; 1322 priv->is_suspending = false; 1323 } 1324 1325 static int omap8250_suspend(struct device *dev) 1326 { 1327 struct omap8250_priv *priv = dev_get_drvdata(dev); 1328 struct uart_8250_port *up = serial8250_get_port(priv->line); 1329 1330 serial8250_suspend_port(priv->line); 1331 1332 pm_runtime_get_sync(dev); 1333 if (!device_may_wakeup(dev)) 1334 priv->wer = 0; 1335 serial_out(up, UART_OMAP_WER, priv->wer); 1336 pm_runtime_mark_last_busy(dev); 1337 pm_runtime_put_autosuspend(dev); 1338 1339 flush_work(&priv->qos_work); 1340 return 0; 1341 } 1342 1343 static int omap8250_resume(struct device *dev) 1344 { 1345 struct omap8250_priv *priv = dev_get_drvdata(dev); 1346 1347 serial8250_resume_port(priv->line); 1348 return 0; 1349 } 1350 #else 1351 #define omap8250_prepare NULL 1352 #define omap8250_complete NULL 1353 #endif 1354 1355 #ifdef CONFIG_PM 1356 static int omap8250_lost_context(struct uart_8250_port *up) 1357 { 1358 u32 val; 1359 1360 val = serial_in(up, UART_OMAP_SCR); 1361 /* 1362 * If we lose context, then SCR is set to its reset value of zero. 1363 * After set_termios() we set bit 3 of SCR (TX_EMPTY_CTL_IT) to 1, 1364 * among other bits, to never set the register back to zero again. 1365 */ 1366 if (!val) 1367 return 1; 1368 return 0; 1369 } 1370 1371 /* TODO: in future, this should happen via API in drivers/reset/ */ 1372 static int omap8250_soft_reset(struct device *dev) 1373 { 1374 struct omap8250_priv *priv = dev_get_drvdata(dev); 1375 struct uart_8250_port *up = serial8250_get_port(priv->line); 1376 int timeout = 100; 1377 int sysc; 1378 int syss; 1379 1380 /* 1381 * At least on omap4, unused uarts may not idle after reset without 1382 * a basic scr dma configuration even with no dma in use. The 1383 * module clkctrl status bits will be 1 instead of 3 blocking idle 1384 * for the whole clockdomain. The softreset below will clear scr, 1385 * and we restore it on resume so this is safe to do on all SoCs 1386 * needing omap8250_soft_reset() quirk. Do it in two writes as 1387 * recommended in the comment for omap8250_update_scr(). 1388 */ 1389 serial_out(up, UART_OMAP_SCR, OMAP_UART_SCR_DMAMODE_1); 1390 serial_out(up, UART_OMAP_SCR, 1391 OMAP_UART_SCR_DMAMODE_1 | OMAP_UART_SCR_DMAMODE_CTL); 1392 1393 sysc = serial_in(up, UART_OMAP_SYSC); 1394 1395 /* softreset the UART */ 1396 sysc |= OMAP_UART_SYSC_SOFTRESET; 1397 serial_out(up, UART_OMAP_SYSC, sysc); 1398 1399 /* By experiments, 1us enough for reset complete on AM335x */ 1400 do { 1401 udelay(1); 1402 syss = serial_in(up, UART_OMAP_SYSS); 1403 } while (--timeout && !(syss & OMAP_UART_SYSS_RESETDONE)); 1404 1405 if (!timeout) { 1406 dev_err(dev, "timed out waiting for reset done\n"); 1407 return -ETIMEDOUT; 1408 } 1409 1410 return 0; 1411 } 1412 1413 static int omap8250_runtime_suspend(struct device *dev) 1414 { 1415 struct omap8250_priv *priv = dev_get_drvdata(dev); 1416 struct uart_8250_port *up; 1417 1418 /* In case runtime-pm tries this before we are setup */ 1419 if (!priv) 1420 return 0; 1421 1422 up = serial8250_get_port(priv->line); 1423 /* 1424 * When using 'no_console_suspend', the console UART must not be 1425 * suspended. Since driver suspend is managed by runtime suspend, 1426 * preventing runtime suspend (by returning error) will keep device 1427 * active during suspend. 1428 */ 1429 if (priv->is_suspending && !console_suspend_enabled) { 1430 if (uart_console(&up->port)) 1431 return -EBUSY; 1432 } 1433 1434 if (priv->habit & UART_ERRATA_CLOCK_DISABLE) { 1435 int ret; 1436 1437 ret = omap8250_soft_reset(dev); 1438 if (ret) 1439 return ret; 1440 1441 /* Restore to UART mode after reset (for wakeup) */ 1442 omap8250_update_mdr1(up, priv); 1443 /* Restore wakeup enable register */ 1444 serial_out(up, UART_OMAP_WER, priv->wer); 1445 } 1446 1447 if (up->dma && up->dma->rxchan) 1448 omap_8250_rx_dma_flush(up); 1449 1450 priv->latency = PM_QOS_CPU_DMA_LAT_DEFAULT_VALUE; 1451 schedule_work(&priv->qos_work); 1452 1453 return 0; 1454 } 1455 1456 static int omap8250_runtime_resume(struct device *dev) 1457 { 1458 struct omap8250_priv *priv = dev_get_drvdata(dev); 1459 struct uart_8250_port *up; 1460 1461 /* In case runtime-pm tries this before we are setup */ 1462 if (!priv) 1463 return 0; 1464 1465 up = serial8250_get_port(priv->line); 1466 1467 if (omap8250_lost_context(up)) 1468 omap8250_restore_regs(up); 1469 1470 if (up->dma && up->dma->rxchan) 1471 omap_8250_rx_dma(up); 1472 1473 priv->latency = priv->calc_latency; 1474 schedule_work(&priv->qos_work); 1475 return 0; 1476 } 1477 #endif 1478 1479 #ifdef CONFIG_SERIAL_8250_OMAP_TTYO_FIXUP 1480 static int __init omap8250_console_fixup(void) 1481 { 1482 char *omap_str; 1483 char *options; 1484 u8 idx; 1485 1486 if (strstr(boot_command_line, "console=ttyS")) 1487 /* user set a ttyS based name for the console */ 1488 return 0; 1489 1490 omap_str = strstr(boot_command_line, "console=ttyO"); 1491 if (!omap_str) 1492 /* user did not set ttyO based console, so we don't care */ 1493 return 0; 1494 1495 omap_str += 12; 1496 if ('0' <= *omap_str && *omap_str <= '9') 1497 idx = *omap_str - '0'; 1498 else 1499 return 0; 1500 1501 omap_str++; 1502 if (omap_str[0] == ',') { 1503 omap_str++; 1504 options = omap_str; 1505 } else { 1506 options = NULL; 1507 } 1508 1509 add_preferred_console("ttyS", idx, options); 1510 pr_err("WARNING: Your 'console=ttyO%d' has been replaced by 'ttyS%d'\n", 1511 idx, idx); 1512 pr_err("This ensures that you still see kernel messages. Please\n"); 1513 pr_err("update your kernel commandline.\n"); 1514 return 0; 1515 } 1516 console_initcall(omap8250_console_fixup); 1517 #endif 1518 1519 static const struct dev_pm_ops omap8250_dev_pm_ops = { 1520 SET_SYSTEM_SLEEP_PM_OPS(omap8250_suspend, omap8250_resume) 1521 SET_RUNTIME_PM_OPS(omap8250_runtime_suspend, 1522 omap8250_runtime_resume, NULL) 1523 .prepare = omap8250_prepare, 1524 .complete = omap8250_complete, 1525 }; 1526 1527 static struct platform_driver omap8250_platform_driver = { 1528 .driver = { 1529 .name = "omap8250", 1530 .pm = &omap8250_dev_pm_ops, 1531 .of_match_table = omap8250_dt_ids, 1532 }, 1533 .probe = omap8250_probe, 1534 .remove = omap8250_remove, 1535 }; 1536 module_platform_driver(omap8250_platform_driver); 1537 1538 MODULE_AUTHOR("Sebastian Andrzej Siewior"); 1539 MODULE_DESCRIPTION("OMAP 8250 Driver"); 1540 MODULE_LICENSE("GPL v2"); 1541