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 #include <linux/clk.h> 12 #include <linux/device.h> 13 #include <linux/io.h> 14 #include <linux/module.h> 15 #include <linux/serial_8250.h> 16 #include <linux/serial_reg.h> 17 #include <linux/tty_flip.h> 18 #include <linux/platform_device.h> 19 #include <linux/slab.h> 20 #include <linux/of.h> 21 #include <linux/of_device.h> 22 #include <linux/of_gpio.h> 23 #include <linux/of_irq.h> 24 #include <linux/delay.h> 25 #include <linux/pm_runtime.h> 26 #include <linux/console.h> 27 #include <linux/pm_qos.h> 28 #include <linux/pm_wakeirq.h> 29 #include <linux/dma-mapping.h> 30 #include <linux/sys_soc.h> 31 32 #include "8250.h" 33 34 #define DEFAULT_CLK_SPEED 48000000 35 36 #define UART_ERRATA_i202_MDR1_ACCESS (1 << 0) 37 #define OMAP_UART_WER_HAS_TX_WAKEUP (1 << 1) 38 #define OMAP_DMA_TX_KICK (1 << 2) 39 /* 40 * See Advisory 21 in AM437x errata SPRZ408B, updated April 2015. 41 * The same errata is applicable to AM335x and DRA7x processors too. 42 */ 43 #define UART_ERRATA_CLOCK_DISABLE (1 << 3) 44 #define UART_HAS_EFR2 BIT(4) 45 #define UART_HAS_RHR_IT_DIS BIT(5) 46 47 #define OMAP_UART_FCR_RX_TRIG 6 48 #define OMAP_UART_FCR_TX_TRIG 4 49 50 /* SCR register bitmasks */ 51 #define OMAP_UART_SCR_RX_TRIG_GRANU1_MASK (1 << 7) 52 #define OMAP_UART_SCR_TX_TRIG_GRANU1_MASK (1 << 6) 53 #define OMAP_UART_SCR_TX_EMPTY (1 << 3) 54 #define OMAP_UART_SCR_DMAMODE_MASK (3 << 1) 55 #define OMAP_UART_SCR_DMAMODE_1 (1 << 1) 56 #define OMAP_UART_SCR_DMAMODE_CTL (1 << 0) 57 58 /* MVR register bitmasks */ 59 #define OMAP_UART_MVR_SCHEME_SHIFT 30 60 #define OMAP_UART_LEGACY_MVR_MAJ_MASK 0xf0 61 #define OMAP_UART_LEGACY_MVR_MAJ_SHIFT 4 62 #define OMAP_UART_LEGACY_MVR_MIN_MASK 0x0f 63 #define OMAP_UART_MVR_MAJ_MASK 0x700 64 #define OMAP_UART_MVR_MAJ_SHIFT 8 65 #define OMAP_UART_MVR_MIN_MASK 0x3f 66 67 /* SYSC register bitmasks */ 68 #define OMAP_UART_SYSC_SOFTRESET (1 << 1) 69 70 /* SYSS register bitmasks */ 71 #define OMAP_UART_SYSS_RESETDONE (1 << 0) 72 73 #define UART_TI752_TLR_TX 0 74 #define UART_TI752_TLR_RX 4 75 76 #define TRIGGER_TLR_MASK(x) ((x & 0x3c) >> 2) 77 #define TRIGGER_FCR_MASK(x) (x & 3) 78 79 /* Enable XON/XOFF flow control on output */ 80 #define OMAP_UART_SW_TX 0x08 81 /* Enable XON/XOFF flow control on input */ 82 #define OMAP_UART_SW_RX 0x02 83 84 #define OMAP_UART_WER_MOD_WKUP 0x7f 85 #define OMAP_UART_TX_WAKEUP_EN (1 << 7) 86 87 #define TX_TRIGGER 1 88 #define RX_TRIGGER 48 89 90 #define OMAP_UART_TCR_RESTORE(x) ((x / 4) << 4) 91 #define OMAP_UART_TCR_HALT(x) ((x / 4) << 0) 92 93 #define UART_BUILD_REVISION(x, y) (((x) << 8) | (y)) 94 95 #define OMAP_UART_REV_46 0x0406 96 #define OMAP_UART_REV_52 0x0502 97 #define OMAP_UART_REV_63 0x0603 98 99 /* Interrupt Enable Register 2 */ 100 #define UART_OMAP_IER2 0x1B 101 #define UART_OMAP_IER2_RHR_IT_DIS BIT(2) 102 103 /* Enhanced features register 2 */ 104 #define UART_OMAP_EFR2 0x23 105 #define UART_OMAP_EFR2_TIMEOUT_BEHAVE BIT(6) 106 107 struct omap8250_priv { 108 int line; 109 u8 habit; 110 u8 mdr1; 111 u8 efr; 112 u8 scr; 113 u8 wer; 114 u8 xon; 115 u8 xoff; 116 u8 delayed_restore; 117 u16 quot; 118 119 u8 tx_trigger; 120 u8 rx_trigger; 121 bool is_suspending; 122 int wakeirq; 123 int wakeups_enabled; 124 u32 latency; 125 u32 calc_latency; 126 struct pm_qos_request pm_qos_request; 127 struct work_struct qos_work; 128 struct uart_8250_dma omap8250_dma; 129 spinlock_t rx_dma_lock; 130 bool rx_dma_broken; 131 bool throttled; 132 }; 133 134 struct omap8250_dma_params { 135 u32 rx_size; 136 u8 rx_trigger; 137 u8 tx_trigger; 138 }; 139 140 struct omap8250_platdata { 141 struct omap8250_dma_params *dma_params; 142 u8 habit; 143 }; 144 145 #ifdef CONFIG_SERIAL_8250_DMA 146 static void omap_8250_rx_dma_flush(struct uart_8250_port *p); 147 #else 148 static inline void omap_8250_rx_dma_flush(struct uart_8250_port *p) { } 149 #endif 150 151 static u32 uart_read(struct uart_8250_port *up, u32 reg) 152 { 153 return readl(up->port.membase + (reg << up->port.regshift)); 154 } 155 156 static void omap8250_set_mctrl(struct uart_port *port, unsigned int mctrl) 157 { 158 struct uart_8250_port *up = up_to_u8250p(port); 159 struct omap8250_priv *priv = up->port.private_data; 160 u8 lcr; 161 162 serial8250_do_set_mctrl(port, mctrl); 163 164 if (!mctrl_gpio_to_gpiod(up->gpios, UART_GPIO_RTS)) { 165 /* 166 * Turn off autoRTS if RTS is lowered and restore autoRTS 167 * setting if RTS is raised 168 */ 169 lcr = serial_in(up, UART_LCR); 170 serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B); 171 if ((mctrl & TIOCM_RTS) && (port->status & UPSTAT_AUTORTS)) 172 priv->efr |= UART_EFR_RTS; 173 else 174 priv->efr &= ~UART_EFR_RTS; 175 serial_out(up, UART_EFR, priv->efr); 176 serial_out(up, UART_LCR, lcr); 177 } 178 } 179 180 /* 181 * Work Around for Errata i202 (2430, 3430, 3630, 4430 and 4460) 182 * The access to uart register after MDR1 Access 183 * causes UART to corrupt data. 184 * 185 * Need a delay = 186 * 5 L4 clock cycles + 5 UART functional clock cycle (@48MHz = ~0.2uS) 187 * give 10 times as much 188 */ 189 static void omap_8250_mdr1_errataset(struct uart_8250_port *up, 190 struct omap8250_priv *priv) 191 { 192 u8 timeout = 255; 193 194 serial_out(up, UART_OMAP_MDR1, priv->mdr1); 195 udelay(2); 196 serial_out(up, UART_FCR, up->fcr | UART_FCR_CLEAR_XMIT | 197 UART_FCR_CLEAR_RCVR); 198 /* 199 * Wait for FIFO to empty: when empty, RX_FIFO_E bit is 0 and 200 * TX_FIFO_E bit is 1. 201 */ 202 while (UART_LSR_THRE != (serial_in(up, UART_LSR) & 203 (UART_LSR_THRE | UART_LSR_DR))) { 204 timeout--; 205 if (!timeout) { 206 /* Should *never* happen. we warn and carry on */ 207 dev_crit(up->port.dev, "Errata i202: timedout %x\n", 208 serial_in(up, UART_LSR)); 209 break; 210 } 211 udelay(1); 212 } 213 } 214 215 static void omap_8250_get_divisor(struct uart_port *port, unsigned int baud, 216 struct omap8250_priv *priv) 217 { 218 unsigned int uartclk = port->uartclk; 219 unsigned int div_13, div_16; 220 unsigned int abs_d13, abs_d16; 221 222 /* 223 * Old custom speed handling. 224 */ 225 if (baud == 38400 && (port->flags & UPF_SPD_MASK) == UPF_SPD_CUST) { 226 priv->quot = port->custom_divisor & UART_DIV_MAX; 227 /* 228 * I assume that nobody is using this. But hey, if somebody 229 * would like to specify the divisor _and_ the mode then the 230 * driver is ready and waiting for it. 231 */ 232 if (port->custom_divisor & (1 << 16)) 233 priv->mdr1 = UART_OMAP_MDR1_13X_MODE; 234 else 235 priv->mdr1 = UART_OMAP_MDR1_16X_MODE; 236 return; 237 } 238 div_13 = DIV_ROUND_CLOSEST(uartclk, 13 * baud); 239 div_16 = DIV_ROUND_CLOSEST(uartclk, 16 * baud); 240 241 if (!div_13) 242 div_13 = 1; 243 if (!div_16) 244 div_16 = 1; 245 246 abs_d13 = abs(baud - uartclk / 13 / div_13); 247 abs_d16 = abs(baud - uartclk / 16 / div_16); 248 249 if (abs_d13 >= abs_d16) { 250 priv->mdr1 = UART_OMAP_MDR1_16X_MODE; 251 priv->quot = div_16; 252 } else { 253 priv->mdr1 = UART_OMAP_MDR1_13X_MODE; 254 priv->quot = div_13; 255 } 256 } 257 258 static void omap8250_update_scr(struct uart_8250_port *up, 259 struct omap8250_priv *priv) 260 { 261 u8 old_scr; 262 263 old_scr = serial_in(up, UART_OMAP_SCR); 264 if (old_scr == priv->scr) 265 return; 266 267 /* 268 * The manual recommends not to enable the DMA mode selector in the SCR 269 * (instead of the FCR) register _and_ selecting the DMA mode as one 270 * register write because this may lead to malfunction. 271 */ 272 if (priv->scr & OMAP_UART_SCR_DMAMODE_MASK) 273 serial_out(up, UART_OMAP_SCR, 274 priv->scr & ~OMAP_UART_SCR_DMAMODE_MASK); 275 serial_out(up, UART_OMAP_SCR, priv->scr); 276 } 277 278 static void omap8250_update_mdr1(struct uart_8250_port *up, 279 struct omap8250_priv *priv) 280 { 281 if (priv->habit & UART_ERRATA_i202_MDR1_ACCESS) 282 omap_8250_mdr1_errataset(up, priv); 283 else 284 serial_out(up, UART_OMAP_MDR1, priv->mdr1); 285 } 286 287 static void omap8250_restore_regs(struct uart_8250_port *up) 288 { 289 struct omap8250_priv *priv = up->port.private_data; 290 struct uart_8250_dma *dma = up->dma; 291 292 if (dma && dma->tx_running) { 293 /* 294 * TCSANOW requests the change to occur immediately however if 295 * we have a TX-DMA operation in progress then it has been 296 * observed that it might stall and never complete. Therefore we 297 * delay DMA completes to prevent this hang from happen. 298 */ 299 priv->delayed_restore = 1; 300 return; 301 } 302 303 serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B); 304 serial_out(up, UART_EFR, UART_EFR_ECB); 305 306 serial_out(up, UART_LCR, UART_LCR_CONF_MODE_A); 307 serial8250_out_MCR(up, UART_MCR_TCRTLR); 308 serial_out(up, UART_FCR, up->fcr); 309 310 omap8250_update_scr(up, priv); 311 312 serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B); 313 314 serial_out(up, UART_TI752_TCR, OMAP_UART_TCR_RESTORE(16) | 315 OMAP_UART_TCR_HALT(52)); 316 serial_out(up, UART_TI752_TLR, 317 TRIGGER_TLR_MASK(priv->tx_trigger) << UART_TI752_TLR_TX | 318 TRIGGER_TLR_MASK(priv->rx_trigger) << UART_TI752_TLR_RX); 319 320 serial_out(up, UART_LCR, 0); 321 322 /* drop TCR + TLR access, we setup XON/XOFF later */ 323 serial8250_out_MCR(up, up->mcr); 324 serial_out(up, UART_IER, up->ier); 325 326 serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B); 327 serial_dl_write(up, priv->quot); 328 329 serial_out(up, UART_EFR, priv->efr); 330 331 /* Configure flow control */ 332 serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B); 333 serial_out(up, UART_XON1, priv->xon); 334 serial_out(up, UART_XOFF1, priv->xoff); 335 336 serial_out(up, UART_LCR, up->lcr); 337 338 omap8250_update_mdr1(up, priv); 339 340 up->port.ops->set_mctrl(&up->port, up->port.mctrl); 341 } 342 343 /* 344 * OMAP can use "CLK / (16 or 13) / div" for baud rate. And then we have have 345 * some differences in how we want to handle flow control. 346 */ 347 static void omap_8250_set_termios(struct uart_port *port, 348 struct ktermios *termios, 349 struct ktermios *old) 350 { 351 struct uart_8250_port *up = up_to_u8250p(port); 352 struct omap8250_priv *priv = up->port.private_data; 353 unsigned char cval = 0; 354 unsigned int baud; 355 356 switch (termios->c_cflag & CSIZE) { 357 case CS5: 358 cval = UART_LCR_WLEN5; 359 break; 360 case CS6: 361 cval = UART_LCR_WLEN6; 362 break; 363 case CS7: 364 cval = UART_LCR_WLEN7; 365 break; 366 default: 367 case CS8: 368 cval = UART_LCR_WLEN8; 369 break; 370 } 371 372 if (termios->c_cflag & CSTOPB) 373 cval |= UART_LCR_STOP; 374 if (termios->c_cflag & PARENB) 375 cval |= UART_LCR_PARITY; 376 if (!(termios->c_cflag & PARODD)) 377 cval |= UART_LCR_EPAR; 378 if (termios->c_cflag & CMSPAR) 379 cval |= UART_LCR_SPAR; 380 381 /* 382 * Ask the core to calculate the divisor for us. 383 */ 384 baud = uart_get_baud_rate(port, termios, old, 385 port->uartclk / 16 / UART_DIV_MAX, 386 port->uartclk / 13); 387 omap_8250_get_divisor(port, baud, priv); 388 389 /* 390 * Ok, we're now changing the port state. Do it with 391 * interrupts disabled. 392 */ 393 pm_runtime_get_sync(port->dev); 394 spin_lock_irq(&port->lock); 395 396 /* 397 * Update the per-port timeout. 398 */ 399 uart_update_timeout(port, termios->c_cflag, baud); 400 401 up->port.read_status_mask = UART_LSR_OE | UART_LSR_THRE | UART_LSR_DR; 402 if (termios->c_iflag & INPCK) 403 up->port.read_status_mask |= UART_LSR_FE | UART_LSR_PE; 404 if (termios->c_iflag & (IGNBRK | PARMRK)) 405 up->port.read_status_mask |= UART_LSR_BI; 406 407 /* 408 * Characters to ignore 409 */ 410 up->port.ignore_status_mask = 0; 411 if (termios->c_iflag & IGNPAR) 412 up->port.ignore_status_mask |= UART_LSR_PE | UART_LSR_FE; 413 if (termios->c_iflag & IGNBRK) { 414 up->port.ignore_status_mask |= UART_LSR_BI; 415 /* 416 * If we're ignoring parity and break indicators, 417 * ignore overruns too (for real raw support). 418 */ 419 if (termios->c_iflag & IGNPAR) 420 up->port.ignore_status_mask |= UART_LSR_OE; 421 } 422 423 /* 424 * ignore all characters if CREAD is not set 425 */ 426 if ((termios->c_cflag & CREAD) == 0) 427 up->port.ignore_status_mask |= UART_LSR_DR; 428 429 /* 430 * Modem status interrupts 431 */ 432 up->ier &= ~UART_IER_MSI; 433 if (UART_ENABLE_MS(&up->port, termios->c_cflag)) 434 up->ier |= UART_IER_MSI; 435 436 up->lcr = cval; 437 /* Up to here it was mostly serial8250_do_set_termios() */ 438 439 /* 440 * We enable TRIG_GRANU for RX and TX and additionally we set 441 * SCR_TX_EMPTY bit. The result is the following: 442 * - RX_TRIGGER amount of bytes in the FIFO will cause an interrupt. 443 * - less than RX_TRIGGER number of bytes will also cause an interrupt 444 * once the UART decides that there no new bytes arriving. 445 * - Once THRE is enabled, the interrupt will be fired once the FIFO is 446 * empty - the trigger level is ignored here. 447 * 448 * Once DMA is enabled: 449 * - UART will assert the TX DMA line once there is room for TX_TRIGGER 450 * bytes in the TX FIFO. On each assert the DMA engine will move 451 * TX_TRIGGER bytes into the FIFO. 452 * - UART will assert the RX DMA line once there are RX_TRIGGER bytes in 453 * the FIFO and move RX_TRIGGER bytes. 454 * This is because threshold and trigger values are the same. 455 */ 456 up->fcr = UART_FCR_ENABLE_FIFO; 457 up->fcr |= TRIGGER_FCR_MASK(priv->tx_trigger) << OMAP_UART_FCR_TX_TRIG; 458 up->fcr |= TRIGGER_FCR_MASK(priv->rx_trigger) << OMAP_UART_FCR_RX_TRIG; 459 460 priv->scr = OMAP_UART_SCR_RX_TRIG_GRANU1_MASK | OMAP_UART_SCR_TX_EMPTY | 461 OMAP_UART_SCR_TX_TRIG_GRANU1_MASK; 462 463 if (up->dma) 464 priv->scr |= OMAP_UART_SCR_DMAMODE_1 | 465 OMAP_UART_SCR_DMAMODE_CTL; 466 467 priv->xon = termios->c_cc[VSTART]; 468 priv->xoff = termios->c_cc[VSTOP]; 469 470 priv->efr = 0; 471 up->port.status &= ~(UPSTAT_AUTOCTS | UPSTAT_AUTORTS | UPSTAT_AUTOXOFF); 472 473 if (termios->c_cflag & CRTSCTS && up->port.flags & UPF_HARD_FLOW && 474 !mctrl_gpio_to_gpiod(up->gpios, UART_GPIO_RTS) && 475 !mctrl_gpio_to_gpiod(up->gpios, UART_GPIO_CTS)) { 476 /* Enable AUTOCTS (autoRTS is enabled when RTS is raised) */ 477 up->port.status |= UPSTAT_AUTOCTS | UPSTAT_AUTORTS; 478 priv->efr |= UART_EFR_CTS; 479 } else if (up->port.flags & UPF_SOFT_FLOW) { 480 /* 481 * OMAP rx s/w flow control is borked; the transmitter remains 482 * stuck off even if rx flow control is subsequently disabled 483 */ 484 485 /* 486 * IXOFF Flag: 487 * Enable XON/XOFF flow control on output. 488 * Transmit XON1, XOFF1 489 */ 490 if (termios->c_iflag & IXOFF) { 491 up->port.status |= UPSTAT_AUTOXOFF; 492 priv->efr |= OMAP_UART_SW_TX; 493 } 494 } 495 omap8250_restore_regs(up); 496 497 spin_unlock_irq(&up->port.lock); 498 pm_runtime_mark_last_busy(port->dev); 499 pm_runtime_put_autosuspend(port->dev); 500 501 /* calculate wakeup latency constraint */ 502 priv->calc_latency = USEC_PER_SEC * 64 * 8 / baud; 503 priv->latency = priv->calc_latency; 504 505 schedule_work(&priv->qos_work); 506 507 /* Don't rewrite B0 */ 508 if (tty_termios_baud_rate(termios)) 509 tty_termios_encode_baud_rate(termios, baud, baud); 510 } 511 512 /* same as 8250 except that we may have extra flow bits set in EFR */ 513 static void omap_8250_pm(struct uart_port *port, unsigned int state, 514 unsigned int oldstate) 515 { 516 struct uart_8250_port *up = up_to_u8250p(port); 517 u8 efr; 518 519 pm_runtime_get_sync(port->dev); 520 serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B); 521 efr = serial_in(up, UART_EFR); 522 serial_out(up, UART_EFR, efr | UART_EFR_ECB); 523 serial_out(up, UART_LCR, 0); 524 525 serial_out(up, UART_IER, (state != 0) ? UART_IERX_SLEEP : 0); 526 serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B); 527 serial_out(up, UART_EFR, efr); 528 serial_out(up, UART_LCR, 0); 529 530 pm_runtime_mark_last_busy(port->dev); 531 pm_runtime_put_autosuspend(port->dev); 532 } 533 534 static void omap_serial_fill_features_erratas(struct uart_8250_port *up, 535 struct omap8250_priv *priv) 536 { 537 const struct soc_device_attribute k3_soc_devices[] = { 538 { .family = "AM65X", }, 539 { .family = "J721E", .revision = "SR1.0" }, 540 { /* sentinel */ } 541 }; 542 u32 mvr, scheme; 543 u16 revision, major, minor; 544 545 mvr = uart_read(up, UART_OMAP_MVER); 546 547 /* Check revision register scheme */ 548 scheme = mvr >> OMAP_UART_MVR_SCHEME_SHIFT; 549 550 switch (scheme) { 551 case 0: /* Legacy Scheme: OMAP2/3 */ 552 /* MINOR_REV[0:4], MAJOR_REV[4:7] */ 553 major = (mvr & OMAP_UART_LEGACY_MVR_MAJ_MASK) >> 554 OMAP_UART_LEGACY_MVR_MAJ_SHIFT; 555 minor = (mvr & OMAP_UART_LEGACY_MVR_MIN_MASK); 556 break; 557 case 1: 558 /* New Scheme: OMAP4+ */ 559 /* MINOR_REV[0:5], MAJOR_REV[8:10] */ 560 major = (mvr & OMAP_UART_MVR_MAJ_MASK) >> 561 OMAP_UART_MVR_MAJ_SHIFT; 562 minor = (mvr & OMAP_UART_MVR_MIN_MASK); 563 break; 564 default: 565 dev_warn(up->port.dev, 566 "Unknown revision, defaulting to highest\n"); 567 /* highest possible revision */ 568 major = 0xff; 569 minor = 0xff; 570 } 571 /* normalize revision for the driver */ 572 revision = UART_BUILD_REVISION(major, minor); 573 574 switch (revision) { 575 case OMAP_UART_REV_46: 576 priv->habit |= UART_ERRATA_i202_MDR1_ACCESS; 577 break; 578 case OMAP_UART_REV_52: 579 priv->habit |= UART_ERRATA_i202_MDR1_ACCESS | 580 OMAP_UART_WER_HAS_TX_WAKEUP; 581 break; 582 case OMAP_UART_REV_63: 583 priv->habit |= UART_ERRATA_i202_MDR1_ACCESS | 584 OMAP_UART_WER_HAS_TX_WAKEUP; 585 break; 586 default: 587 break; 588 } 589 590 /* 591 * AM65x SR1.0, AM65x SR2.0 and J721e SR1.0 don't 592 * don't have RHR_IT_DIS bit in IER2 register. So drop to flag 593 * to enable errata workaround. 594 */ 595 if (soc_device_match(k3_soc_devices)) 596 priv->habit &= ~UART_HAS_RHR_IT_DIS; 597 } 598 599 static void omap8250_uart_qos_work(struct work_struct *work) 600 { 601 struct omap8250_priv *priv; 602 603 priv = container_of(work, struct omap8250_priv, qos_work); 604 cpu_latency_qos_update_request(&priv->pm_qos_request, priv->latency); 605 } 606 607 #ifdef CONFIG_SERIAL_8250_DMA 608 static int omap_8250_dma_handle_irq(struct uart_port *port); 609 #endif 610 611 static irqreturn_t omap8250_irq(int irq, void *dev_id) 612 { 613 struct uart_port *port = dev_id; 614 struct uart_8250_port *up = up_to_u8250p(port); 615 unsigned int iir; 616 int ret; 617 618 #ifdef CONFIG_SERIAL_8250_DMA 619 if (up->dma) { 620 ret = omap_8250_dma_handle_irq(port); 621 return IRQ_RETVAL(ret); 622 } 623 #endif 624 625 serial8250_rpm_get(up); 626 iir = serial_port_in(port, UART_IIR); 627 ret = serial8250_handle_irq(port, iir); 628 serial8250_rpm_put(up); 629 630 return IRQ_RETVAL(ret); 631 } 632 633 static int omap_8250_startup(struct uart_port *port) 634 { 635 struct uart_8250_port *up = up_to_u8250p(port); 636 struct omap8250_priv *priv = port->private_data; 637 int ret; 638 639 if (priv->wakeirq) { 640 ret = dev_pm_set_dedicated_wake_irq(port->dev, priv->wakeirq); 641 if (ret) 642 return ret; 643 } 644 645 pm_runtime_get_sync(port->dev); 646 647 up->mcr = 0; 648 serial_out(up, UART_FCR, UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT); 649 650 serial_out(up, UART_LCR, UART_LCR_WLEN8); 651 652 up->lsr_saved_flags = 0; 653 up->msr_saved_flags = 0; 654 655 /* Disable DMA for console UART */ 656 if (uart_console(port)) 657 up->dma = NULL; 658 659 if (up->dma) { 660 ret = serial8250_request_dma(up); 661 if (ret) { 662 dev_warn_ratelimited(port->dev, 663 "failed to request DMA\n"); 664 up->dma = NULL; 665 } 666 } 667 668 ret = request_irq(port->irq, omap8250_irq, IRQF_SHARED, 669 dev_name(port->dev), port); 670 if (ret < 0) 671 goto err; 672 673 up->ier = UART_IER_RLSI | UART_IER_RDI; 674 serial_out(up, UART_IER, up->ier); 675 676 #ifdef CONFIG_PM 677 up->capabilities |= UART_CAP_RPM; 678 #endif 679 680 /* Enable module level wake up */ 681 priv->wer = OMAP_UART_WER_MOD_WKUP; 682 if (priv->habit & OMAP_UART_WER_HAS_TX_WAKEUP) 683 priv->wer |= OMAP_UART_TX_WAKEUP_EN; 684 serial_out(up, UART_OMAP_WER, priv->wer); 685 686 if (up->dma && !(priv->habit & UART_HAS_EFR2)) 687 up->dma->rx_dma(up); 688 689 pm_runtime_mark_last_busy(port->dev); 690 pm_runtime_put_autosuspend(port->dev); 691 return 0; 692 err: 693 pm_runtime_mark_last_busy(port->dev); 694 pm_runtime_put_autosuspend(port->dev); 695 dev_pm_clear_wake_irq(port->dev); 696 return ret; 697 } 698 699 static void omap_8250_shutdown(struct uart_port *port) 700 { 701 struct uart_8250_port *up = up_to_u8250p(port); 702 struct omap8250_priv *priv = port->private_data; 703 704 flush_work(&priv->qos_work); 705 if (up->dma) 706 omap_8250_rx_dma_flush(up); 707 708 pm_runtime_get_sync(port->dev); 709 710 serial_out(up, UART_OMAP_WER, 0); 711 if (priv->habit & UART_HAS_EFR2) 712 serial_out(up, UART_OMAP_EFR2, 0x0); 713 714 up->ier = 0; 715 serial_out(up, UART_IER, 0); 716 717 if (up->dma) 718 serial8250_release_dma(up); 719 720 /* 721 * Disable break condition and FIFOs 722 */ 723 if (up->lcr & UART_LCR_SBC) 724 serial_out(up, UART_LCR, up->lcr & ~UART_LCR_SBC); 725 serial_out(up, UART_FCR, UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT); 726 727 pm_runtime_mark_last_busy(port->dev); 728 pm_runtime_put_autosuspend(port->dev); 729 free_irq(port->irq, port); 730 dev_pm_clear_wake_irq(port->dev); 731 } 732 733 static void omap_8250_throttle(struct uart_port *port) 734 { 735 struct omap8250_priv *priv = port->private_data; 736 unsigned long flags; 737 738 pm_runtime_get_sync(port->dev); 739 740 spin_lock_irqsave(&port->lock, flags); 741 port->ops->stop_rx(port); 742 priv->throttled = true; 743 spin_unlock_irqrestore(&port->lock, flags); 744 745 pm_runtime_mark_last_busy(port->dev); 746 pm_runtime_put_autosuspend(port->dev); 747 } 748 749 static void omap_8250_unthrottle(struct uart_port *port) 750 { 751 struct omap8250_priv *priv = port->private_data; 752 struct uart_8250_port *up = up_to_u8250p(port); 753 unsigned long flags; 754 755 pm_runtime_get_sync(port->dev); 756 757 spin_lock_irqsave(&port->lock, flags); 758 priv->throttled = false; 759 if (up->dma) 760 up->dma->rx_dma(up); 761 up->ier |= UART_IER_RLSI | UART_IER_RDI; 762 port->read_status_mask |= UART_LSR_DR; 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 /* Must be called while priv->rx_dma_lock is held */ 774 static void __dma_rx_do_complete(struct uart_8250_port *p) 775 { 776 struct uart_8250_dma *dma = p->dma; 777 struct tty_port *tty_port = &p->port.state->port; 778 struct omap8250_priv *priv = p->port.private_data; 779 struct dma_chan *rxchan = dma->rxchan; 780 dma_cookie_t cookie; 781 struct dma_tx_state state; 782 int count; 783 int ret; 784 u32 reg; 785 786 if (!dma->rx_running) 787 goto out; 788 789 cookie = dma->rx_cookie; 790 dma->rx_running = 0; 791 792 /* Re-enable RX FIFO interrupt now that transfer is complete */ 793 if (priv->habit & UART_HAS_RHR_IT_DIS) { 794 reg = serial_in(p, UART_OMAP_IER2); 795 reg &= ~UART_OMAP_IER2_RHR_IT_DIS; 796 serial_out(p, UART_OMAP_IER2, UART_OMAP_IER2_RHR_IT_DIS); 797 } 798 799 dmaengine_tx_status(rxchan, cookie, &state); 800 801 count = dma->rx_size - state.residue + state.in_flight_bytes; 802 if (count < dma->rx_size) { 803 dmaengine_terminate_async(rxchan); 804 805 /* 806 * Poll for teardown to complete which guarantees in 807 * flight data is drained. 808 */ 809 if (state.in_flight_bytes) { 810 int poll_count = 25; 811 812 while (dmaengine_tx_status(rxchan, cookie, NULL) && 813 poll_count--) 814 cpu_relax(); 815 816 if (!poll_count) 817 dev_err(p->port.dev, "teardown incomplete\n"); 818 } 819 } 820 if (!count) 821 goto out; 822 ret = tty_insert_flip_string(tty_port, dma->rx_buf, count); 823 824 p->port.icount.rx += ret; 825 p->port.icount.buf_overrun += count - ret; 826 out: 827 828 tty_flip_buffer_push(tty_port); 829 } 830 831 static void __dma_rx_complete(void *param) 832 { 833 struct uart_8250_port *p = param; 834 struct omap8250_priv *priv = p->port.private_data; 835 struct uart_8250_dma *dma = p->dma; 836 struct dma_tx_state state; 837 unsigned long flags; 838 839 spin_lock_irqsave(&p->port.lock, flags); 840 841 /* 842 * If the tx status is not DMA_COMPLETE, then this is a delayed 843 * completion callback. A previous RX timeout flush would have 844 * already pushed the data, so exit. 845 */ 846 if (dmaengine_tx_status(dma->rxchan, dma->rx_cookie, &state) != 847 DMA_COMPLETE) { 848 spin_unlock_irqrestore(&p->port.lock, flags); 849 return; 850 } 851 __dma_rx_do_complete(p); 852 if (!priv->throttled) { 853 p->ier |= UART_IER_RLSI | UART_IER_RDI; 854 serial_out(p, UART_IER, p->ier); 855 if (!(priv->habit & UART_HAS_EFR2)) 856 omap_8250_rx_dma(p); 857 } 858 859 spin_unlock_irqrestore(&p->port.lock, flags); 860 } 861 862 static void omap_8250_rx_dma_flush(struct uart_8250_port *p) 863 { 864 struct omap8250_priv *priv = p->port.private_data; 865 struct uart_8250_dma *dma = p->dma; 866 struct dma_tx_state state; 867 unsigned long flags; 868 int ret; 869 870 spin_lock_irqsave(&priv->rx_dma_lock, flags); 871 872 if (!dma->rx_running) { 873 spin_unlock_irqrestore(&priv->rx_dma_lock, flags); 874 return; 875 } 876 877 ret = dmaengine_tx_status(dma->rxchan, dma->rx_cookie, &state); 878 if (ret == DMA_IN_PROGRESS) { 879 ret = dmaengine_pause(dma->rxchan); 880 if (WARN_ON_ONCE(ret)) 881 priv->rx_dma_broken = true; 882 } 883 __dma_rx_do_complete(p); 884 spin_unlock_irqrestore(&priv->rx_dma_lock, flags); 885 } 886 887 static int omap_8250_rx_dma(struct uart_8250_port *p) 888 { 889 struct omap8250_priv *priv = p->port.private_data; 890 struct uart_8250_dma *dma = p->dma; 891 int err = 0; 892 struct dma_async_tx_descriptor *desc; 893 unsigned long flags; 894 u32 reg; 895 896 if (priv->rx_dma_broken) 897 return -EINVAL; 898 899 spin_lock_irqsave(&priv->rx_dma_lock, flags); 900 901 if (dma->rx_running) { 902 enum dma_status state; 903 904 state = dmaengine_tx_status(dma->rxchan, dma->rx_cookie, NULL); 905 if (state == DMA_COMPLETE) { 906 /* 907 * Disable RX interrupts to allow RX DMA completion 908 * callback to run. 909 */ 910 p->ier &= ~(UART_IER_RLSI | UART_IER_RDI); 911 serial_out(p, UART_IER, p->ier); 912 } 913 goto out; 914 } 915 916 desc = dmaengine_prep_slave_single(dma->rxchan, dma->rx_addr, 917 dma->rx_size, DMA_DEV_TO_MEM, 918 DMA_PREP_INTERRUPT | DMA_CTRL_ACK); 919 if (!desc) { 920 err = -EBUSY; 921 goto out; 922 } 923 924 dma->rx_running = 1; 925 desc->callback = __dma_rx_complete; 926 desc->callback_param = p; 927 928 dma->rx_cookie = dmaengine_submit(desc); 929 930 /* 931 * Disable RX FIFO interrupt while RX DMA is enabled, else 932 * spurious interrupt may be raised when data is in the RX FIFO 933 * but is yet to be drained by DMA. 934 */ 935 if (priv->habit & UART_HAS_RHR_IT_DIS) { 936 reg = serial_in(p, UART_OMAP_IER2); 937 reg |= UART_OMAP_IER2_RHR_IT_DIS; 938 serial_out(p, UART_OMAP_IER2, UART_OMAP_IER2_RHR_IT_DIS); 939 } 940 941 dma_async_issue_pending(dma->rxchan); 942 out: 943 spin_unlock_irqrestore(&priv->rx_dma_lock, flags); 944 return err; 945 } 946 947 static int omap_8250_tx_dma(struct uart_8250_port *p); 948 949 static void omap_8250_dma_tx_complete(void *param) 950 { 951 struct uart_8250_port *p = param; 952 struct uart_8250_dma *dma = p->dma; 953 struct circ_buf *xmit = &p->port.state->xmit; 954 unsigned long flags; 955 bool en_thri = false; 956 struct omap8250_priv *priv = p->port.private_data; 957 958 dma_sync_single_for_cpu(dma->txchan->device->dev, dma->tx_addr, 959 UART_XMIT_SIZE, DMA_TO_DEVICE); 960 961 spin_lock_irqsave(&p->port.lock, flags); 962 963 dma->tx_running = 0; 964 965 xmit->tail += dma->tx_size; 966 xmit->tail &= UART_XMIT_SIZE - 1; 967 p->port.icount.tx += dma->tx_size; 968 969 if (priv->delayed_restore) { 970 priv->delayed_restore = 0; 971 omap8250_restore_regs(p); 972 } 973 974 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) 975 uart_write_wakeup(&p->port); 976 977 if (!uart_circ_empty(xmit) && !uart_tx_stopped(&p->port)) { 978 int ret; 979 980 ret = omap_8250_tx_dma(p); 981 if (ret) 982 en_thri = true; 983 } else if (p->capabilities & UART_CAP_RPM) { 984 en_thri = true; 985 } 986 987 if (en_thri) { 988 dma->tx_err = 1; 989 serial8250_set_THRI(p); 990 } 991 992 spin_unlock_irqrestore(&p->port.lock, flags); 993 } 994 995 static int omap_8250_tx_dma(struct uart_8250_port *p) 996 { 997 struct uart_8250_dma *dma = p->dma; 998 struct omap8250_priv *priv = p->port.private_data; 999 struct circ_buf *xmit = &p->port.state->xmit; 1000 struct dma_async_tx_descriptor *desc; 1001 unsigned int skip_byte = 0; 1002 int ret; 1003 1004 if (dma->tx_running) 1005 return 0; 1006 if (uart_tx_stopped(&p->port) || uart_circ_empty(xmit)) { 1007 1008 /* 1009 * Even if no data, we need to return an error for the two cases 1010 * below so serial8250_tx_chars() is invoked and properly clears 1011 * THRI and/or runtime suspend. 1012 */ 1013 if (dma->tx_err || p->capabilities & UART_CAP_RPM) { 1014 ret = -EBUSY; 1015 goto err; 1016 } 1017 serial8250_clear_THRI(p); 1018 return 0; 1019 } 1020 1021 dma->tx_size = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE); 1022 if (priv->habit & OMAP_DMA_TX_KICK) { 1023 u8 tx_lvl; 1024 1025 /* 1026 * We need to put the first byte into the FIFO in order to start 1027 * the DMA transfer. For transfers smaller than four bytes we 1028 * don't bother doing DMA at all. It seem not matter if there 1029 * are still bytes in the FIFO from the last transfer (in case 1030 * we got here directly from omap_8250_dma_tx_complete()). Bytes 1031 * leaving the FIFO seem not to trigger the DMA transfer. It is 1032 * really the byte that we put into the FIFO. 1033 * If the FIFO is already full then we most likely got here from 1034 * omap_8250_dma_tx_complete(). And this means the DMA engine 1035 * just completed its work. We don't have to wait the complete 1036 * 86us at 115200,8n1 but around 60us (not to mention lower 1037 * baudrates). So in that case we take the interrupt and try 1038 * again with an empty FIFO. 1039 */ 1040 tx_lvl = serial_in(p, UART_OMAP_TX_LVL); 1041 if (tx_lvl == p->tx_loadsz) { 1042 ret = -EBUSY; 1043 goto err; 1044 } 1045 if (dma->tx_size < 4) { 1046 ret = -EINVAL; 1047 goto err; 1048 } 1049 skip_byte = 1; 1050 } 1051 1052 desc = dmaengine_prep_slave_single(dma->txchan, 1053 dma->tx_addr + xmit->tail + skip_byte, 1054 dma->tx_size - skip_byte, DMA_MEM_TO_DEV, 1055 DMA_PREP_INTERRUPT | DMA_CTRL_ACK); 1056 if (!desc) { 1057 ret = -EBUSY; 1058 goto err; 1059 } 1060 1061 dma->tx_running = 1; 1062 1063 desc->callback = omap_8250_dma_tx_complete; 1064 desc->callback_param = p; 1065 1066 dma->tx_cookie = dmaengine_submit(desc); 1067 1068 dma_sync_single_for_device(dma->txchan->device->dev, dma->tx_addr, 1069 UART_XMIT_SIZE, DMA_TO_DEVICE); 1070 1071 dma_async_issue_pending(dma->txchan); 1072 if (dma->tx_err) 1073 dma->tx_err = 0; 1074 1075 serial8250_clear_THRI(p); 1076 if (skip_byte) 1077 serial_out(p, UART_TX, xmit->buf[xmit->tail]); 1078 return 0; 1079 err: 1080 dma->tx_err = 1; 1081 return ret; 1082 } 1083 1084 static bool handle_rx_dma(struct uart_8250_port *up, unsigned int iir) 1085 { 1086 switch (iir & 0x3f) { 1087 case UART_IIR_RLSI: 1088 case UART_IIR_RX_TIMEOUT: 1089 case UART_IIR_RDI: 1090 omap_8250_rx_dma_flush(up); 1091 return true; 1092 } 1093 return omap_8250_rx_dma(up); 1094 } 1095 1096 static unsigned char omap_8250_handle_rx_dma(struct uart_8250_port *up, 1097 u8 iir, unsigned char status) 1098 { 1099 if ((status & (UART_LSR_DR | UART_LSR_BI)) && 1100 (iir & UART_IIR_RDI)) { 1101 if (handle_rx_dma(up, iir)) { 1102 status = serial8250_rx_chars(up, status); 1103 omap_8250_rx_dma(up); 1104 } 1105 } 1106 1107 return status; 1108 } 1109 1110 static void am654_8250_handle_rx_dma(struct uart_8250_port *up, u8 iir, 1111 unsigned char status) 1112 { 1113 /* 1114 * Queue a new transfer if FIFO has data. 1115 */ 1116 if ((status & (UART_LSR_DR | UART_LSR_BI)) && 1117 (up->ier & UART_IER_RDI)) { 1118 omap_8250_rx_dma(up); 1119 serial_out(up, UART_OMAP_EFR2, UART_OMAP_EFR2_TIMEOUT_BEHAVE); 1120 } else if ((iir & 0x3f) == UART_IIR_RX_TIMEOUT) { 1121 /* 1122 * Disable RX timeout, read IIR to clear 1123 * current timeout condition, clear EFR2 to 1124 * periodic timeouts, re-enable interrupts. 1125 */ 1126 up->ier &= ~(UART_IER_RLSI | UART_IER_RDI); 1127 serial_out(up, UART_IER, up->ier); 1128 omap_8250_rx_dma_flush(up); 1129 serial_in(up, UART_IIR); 1130 serial_out(up, UART_OMAP_EFR2, 0x0); 1131 up->ier |= UART_IER_RLSI | UART_IER_RDI; 1132 serial_out(up, UART_IER, up->ier); 1133 } 1134 } 1135 1136 /* 1137 * This is mostly serial8250_handle_irq(). We have a slightly different DMA 1138 * hoook for RX/TX and need different logic for them in the ISR. Therefore we 1139 * use the default routine in the non-DMA case and this one for with DMA. 1140 */ 1141 static int omap_8250_dma_handle_irq(struct uart_port *port) 1142 { 1143 struct uart_8250_port *up = up_to_u8250p(port); 1144 struct omap8250_priv *priv = up->port.private_data; 1145 unsigned char status; 1146 unsigned long flags; 1147 u8 iir; 1148 1149 serial8250_rpm_get(up); 1150 1151 iir = serial_port_in(port, UART_IIR); 1152 if (iir & UART_IIR_NO_INT) { 1153 serial8250_rpm_put(up); 1154 return IRQ_HANDLED; 1155 } 1156 1157 spin_lock_irqsave(&port->lock, flags); 1158 1159 status = serial_port_in(port, UART_LSR); 1160 1161 if (priv->habit & UART_HAS_EFR2) 1162 am654_8250_handle_rx_dma(up, iir, status); 1163 else 1164 status = omap_8250_handle_rx_dma(up, iir, status); 1165 1166 serial8250_modem_status(up); 1167 if (status & UART_LSR_THRE && up->dma->tx_err) { 1168 if (uart_tx_stopped(&up->port) || 1169 uart_circ_empty(&up->port.state->xmit)) { 1170 up->dma->tx_err = 0; 1171 serial8250_tx_chars(up); 1172 } else { 1173 /* 1174 * try again due to an earlier failer which 1175 * might have been resolved by now. 1176 */ 1177 if (omap_8250_tx_dma(up)) 1178 serial8250_tx_chars(up); 1179 } 1180 } 1181 1182 uart_unlock_and_check_sysrq(port, flags); 1183 serial8250_rpm_put(up); 1184 return 1; 1185 } 1186 1187 static bool the_no_dma_filter_fn(struct dma_chan *chan, void *param) 1188 { 1189 return false; 1190 } 1191 1192 #else 1193 1194 static inline int omap_8250_rx_dma(struct uart_8250_port *p) 1195 { 1196 return -EINVAL; 1197 } 1198 #endif 1199 1200 static int omap8250_no_handle_irq(struct uart_port *port) 1201 { 1202 /* IRQ has not been requested but handling irq? */ 1203 WARN_ONCE(1, "Unexpected irq handling before port startup\n"); 1204 return 0; 1205 } 1206 1207 static struct omap8250_dma_params am654_dma = { 1208 .rx_size = SZ_2K, 1209 .rx_trigger = 1, 1210 .tx_trigger = TX_TRIGGER, 1211 }; 1212 1213 static struct omap8250_dma_params am33xx_dma = { 1214 .rx_size = RX_TRIGGER, 1215 .rx_trigger = RX_TRIGGER, 1216 .tx_trigger = TX_TRIGGER, 1217 }; 1218 1219 static struct omap8250_platdata am654_platdata = { 1220 .dma_params = &am654_dma, 1221 .habit = UART_HAS_EFR2 | UART_HAS_RHR_IT_DIS, 1222 }; 1223 1224 static struct omap8250_platdata am33xx_platdata = { 1225 .dma_params = &am33xx_dma, 1226 .habit = OMAP_DMA_TX_KICK | UART_ERRATA_CLOCK_DISABLE, 1227 }; 1228 1229 static struct omap8250_platdata omap4_platdata = { 1230 .dma_params = &am33xx_dma, 1231 .habit = UART_ERRATA_CLOCK_DISABLE, 1232 }; 1233 1234 static const struct of_device_id omap8250_dt_ids[] = { 1235 { .compatible = "ti,am654-uart", .data = &am654_platdata, }, 1236 { .compatible = "ti,omap2-uart" }, 1237 { .compatible = "ti,omap3-uart" }, 1238 { .compatible = "ti,omap4-uart", .data = &omap4_platdata, }, 1239 { .compatible = "ti,am3352-uart", .data = &am33xx_platdata, }, 1240 { .compatible = "ti,am4372-uart", .data = &am33xx_platdata, }, 1241 { .compatible = "ti,dra742-uart", .data = &omap4_platdata, }, 1242 {}, 1243 }; 1244 MODULE_DEVICE_TABLE(of, omap8250_dt_ids); 1245 1246 static int omap8250_probe(struct platform_device *pdev) 1247 { 1248 struct device_node *np = pdev->dev.of_node; 1249 struct omap8250_priv *priv; 1250 const struct omap8250_platdata *pdata; 1251 struct uart_8250_port up; 1252 struct resource *regs; 1253 void __iomem *membase; 1254 int irq, ret; 1255 1256 irq = platform_get_irq(pdev, 0); 1257 if (irq < 0) 1258 return irq; 1259 1260 regs = platform_get_resource(pdev, IORESOURCE_MEM, 0); 1261 if (!regs) { 1262 dev_err(&pdev->dev, "missing registers\n"); 1263 return -EINVAL; 1264 } 1265 1266 priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); 1267 if (!priv) 1268 return -ENOMEM; 1269 1270 membase = devm_ioremap(&pdev->dev, regs->start, 1271 resource_size(regs)); 1272 if (!membase) 1273 return -ENODEV; 1274 1275 memset(&up, 0, sizeof(up)); 1276 up.port.dev = &pdev->dev; 1277 up.port.mapbase = regs->start; 1278 up.port.membase = membase; 1279 up.port.irq = irq; 1280 /* 1281 * It claims to be 16C750 compatible however it is a little different. 1282 * It has EFR and has no FCR7_64byte bit. The AFE (which it claims to 1283 * have) is enabled via EFR instead of MCR. The type is set here 8250 1284 * just to get things going. UNKNOWN does not work for a few reasons and 1285 * we don't need our own type since we don't use 8250's set_termios() 1286 * or pm callback. 1287 */ 1288 up.port.type = PORT_8250; 1289 up.port.iotype = UPIO_MEM; 1290 up.port.flags = UPF_FIXED_PORT | UPF_FIXED_TYPE | UPF_SOFT_FLOW | 1291 UPF_HARD_FLOW; 1292 up.port.private_data = priv; 1293 1294 up.port.regshift = 2; 1295 up.port.fifosize = 64; 1296 up.tx_loadsz = 64; 1297 up.capabilities = UART_CAP_FIFO; 1298 #ifdef CONFIG_PM 1299 /* 1300 * Runtime PM is mostly transparent. However to do it right we need to a 1301 * TX empty interrupt before we can put the device to auto idle. So if 1302 * PM is not enabled we don't add that flag and can spare that one extra 1303 * interrupt in the TX path. 1304 */ 1305 up.capabilities |= UART_CAP_RPM; 1306 #endif 1307 up.port.set_termios = omap_8250_set_termios; 1308 up.port.set_mctrl = omap8250_set_mctrl; 1309 up.port.pm = omap_8250_pm; 1310 up.port.startup = omap_8250_startup; 1311 up.port.shutdown = omap_8250_shutdown; 1312 up.port.throttle = omap_8250_throttle; 1313 up.port.unthrottle = omap_8250_unthrottle; 1314 up.port.rs485_config = serial8250_em485_config; 1315 up.rs485_start_tx = serial8250_em485_start_tx; 1316 up.rs485_stop_tx = serial8250_em485_stop_tx; 1317 up.port.has_sysrq = IS_ENABLED(CONFIG_SERIAL_8250_CONSOLE); 1318 1319 ret = of_alias_get_id(np, "serial"); 1320 if (ret < 0) { 1321 dev_err(&pdev->dev, "failed to get alias\n"); 1322 return ret; 1323 } 1324 up.port.line = ret; 1325 1326 if (of_property_read_u32(np, "clock-frequency", &up.port.uartclk)) { 1327 struct clk *clk; 1328 1329 clk = devm_clk_get(&pdev->dev, NULL); 1330 if (IS_ERR(clk)) { 1331 if (PTR_ERR(clk) == -EPROBE_DEFER) 1332 return -EPROBE_DEFER; 1333 } else { 1334 up.port.uartclk = clk_get_rate(clk); 1335 } 1336 } 1337 1338 priv->wakeirq = irq_of_parse_and_map(np, 1); 1339 1340 pdata = of_device_get_match_data(&pdev->dev); 1341 if (pdata) 1342 priv->habit |= pdata->habit; 1343 1344 if (!up.port.uartclk) { 1345 up.port.uartclk = DEFAULT_CLK_SPEED; 1346 dev_warn(&pdev->dev, 1347 "No clock speed specified: using default: %d\n", 1348 DEFAULT_CLK_SPEED); 1349 } 1350 1351 priv->latency = PM_QOS_CPU_LATENCY_DEFAULT_VALUE; 1352 priv->calc_latency = PM_QOS_CPU_LATENCY_DEFAULT_VALUE; 1353 cpu_latency_qos_add_request(&priv->pm_qos_request, priv->latency); 1354 INIT_WORK(&priv->qos_work, omap8250_uart_qos_work); 1355 1356 spin_lock_init(&priv->rx_dma_lock); 1357 1358 device_init_wakeup(&pdev->dev, true); 1359 pm_runtime_enable(&pdev->dev); 1360 pm_runtime_use_autosuspend(&pdev->dev); 1361 1362 /* 1363 * Disable runtime PM until autosuspend delay unless specifically 1364 * enabled by the user via sysfs. This is the historic way to 1365 * prevent an unsafe default policy with lossy characters on wake-up. 1366 * For serdev devices this is not needed, the policy can be managed by 1367 * the serdev driver. 1368 */ 1369 if (!of_get_available_child_count(pdev->dev.of_node)) 1370 pm_runtime_set_autosuspend_delay(&pdev->dev, -1); 1371 1372 pm_runtime_irq_safe(&pdev->dev); 1373 1374 pm_runtime_get_sync(&pdev->dev); 1375 1376 omap_serial_fill_features_erratas(&up, priv); 1377 up.port.handle_irq = omap8250_no_handle_irq; 1378 priv->rx_trigger = RX_TRIGGER; 1379 priv->tx_trigger = TX_TRIGGER; 1380 #ifdef CONFIG_SERIAL_8250_DMA 1381 /* 1382 * Oh DMA support. If there are no DMA properties in the DT then 1383 * we will fall back to a generic DMA channel which does not 1384 * really work here. To ensure that we do not get a generic DMA 1385 * channel assigned, we have the the_no_dma_filter_fn() here. 1386 * To avoid "failed to request DMA" messages we check for DMA 1387 * properties in DT. 1388 */ 1389 ret = of_property_count_strings(np, "dma-names"); 1390 if (ret == 2) { 1391 struct omap8250_dma_params *dma_params = NULL; 1392 1393 up.dma = &priv->omap8250_dma; 1394 up.dma->fn = the_no_dma_filter_fn; 1395 up.dma->tx_dma = omap_8250_tx_dma; 1396 up.dma->rx_dma = omap_8250_rx_dma; 1397 if (pdata) 1398 dma_params = pdata->dma_params; 1399 1400 if (dma_params) { 1401 up.dma->rx_size = dma_params->rx_size; 1402 up.dma->rxconf.src_maxburst = dma_params->rx_trigger; 1403 up.dma->txconf.dst_maxburst = dma_params->tx_trigger; 1404 priv->rx_trigger = dma_params->rx_trigger; 1405 priv->tx_trigger = dma_params->tx_trigger; 1406 } else { 1407 up.dma->rx_size = RX_TRIGGER; 1408 up.dma->rxconf.src_maxburst = RX_TRIGGER; 1409 up.dma->txconf.dst_maxburst = TX_TRIGGER; 1410 } 1411 } 1412 #endif 1413 ret = serial8250_register_8250_port(&up); 1414 if (ret < 0) { 1415 dev_err(&pdev->dev, "unable to register 8250 port\n"); 1416 goto err; 1417 } 1418 priv->line = ret; 1419 platform_set_drvdata(pdev, priv); 1420 pm_runtime_mark_last_busy(&pdev->dev); 1421 pm_runtime_put_autosuspend(&pdev->dev); 1422 return 0; 1423 err: 1424 pm_runtime_dont_use_autosuspend(&pdev->dev); 1425 pm_runtime_put_sync(&pdev->dev); 1426 pm_runtime_disable(&pdev->dev); 1427 return ret; 1428 } 1429 1430 static int omap8250_remove(struct platform_device *pdev) 1431 { 1432 struct omap8250_priv *priv = platform_get_drvdata(pdev); 1433 1434 pm_runtime_dont_use_autosuspend(&pdev->dev); 1435 pm_runtime_put_sync(&pdev->dev); 1436 pm_runtime_disable(&pdev->dev); 1437 serial8250_unregister_port(priv->line); 1438 cpu_latency_qos_remove_request(&priv->pm_qos_request); 1439 device_init_wakeup(&pdev->dev, false); 1440 return 0; 1441 } 1442 1443 #ifdef CONFIG_PM_SLEEP 1444 static int omap8250_prepare(struct device *dev) 1445 { 1446 struct omap8250_priv *priv = dev_get_drvdata(dev); 1447 1448 if (!priv) 1449 return 0; 1450 priv->is_suspending = true; 1451 return 0; 1452 } 1453 1454 static void omap8250_complete(struct device *dev) 1455 { 1456 struct omap8250_priv *priv = dev_get_drvdata(dev); 1457 1458 if (!priv) 1459 return; 1460 priv->is_suspending = false; 1461 } 1462 1463 static int omap8250_suspend(struct device *dev) 1464 { 1465 struct omap8250_priv *priv = dev_get_drvdata(dev); 1466 struct uart_8250_port *up = serial8250_get_port(priv->line); 1467 1468 serial8250_suspend_port(priv->line); 1469 1470 pm_runtime_get_sync(dev); 1471 if (!device_may_wakeup(dev)) 1472 priv->wer = 0; 1473 serial_out(up, UART_OMAP_WER, priv->wer); 1474 pm_runtime_mark_last_busy(dev); 1475 pm_runtime_put_autosuspend(dev); 1476 1477 flush_work(&priv->qos_work); 1478 return 0; 1479 } 1480 1481 static int omap8250_resume(struct device *dev) 1482 { 1483 struct omap8250_priv *priv = dev_get_drvdata(dev); 1484 1485 serial8250_resume_port(priv->line); 1486 return 0; 1487 } 1488 #else 1489 #define omap8250_prepare NULL 1490 #define omap8250_complete NULL 1491 #endif 1492 1493 #ifdef CONFIG_PM 1494 static int omap8250_lost_context(struct uart_8250_port *up) 1495 { 1496 u32 val; 1497 1498 val = serial_in(up, UART_OMAP_SCR); 1499 /* 1500 * If we lose context, then SCR is set to its reset value of zero. 1501 * After set_termios() we set bit 3 of SCR (TX_EMPTY_CTL_IT) to 1, 1502 * among other bits, to never set the register back to zero again. 1503 */ 1504 if (!val) 1505 return 1; 1506 return 0; 1507 } 1508 1509 /* TODO: in future, this should happen via API in drivers/reset/ */ 1510 static int omap8250_soft_reset(struct device *dev) 1511 { 1512 struct omap8250_priv *priv = dev_get_drvdata(dev); 1513 struct uart_8250_port *up = serial8250_get_port(priv->line); 1514 int timeout = 100; 1515 int sysc; 1516 int syss; 1517 1518 /* 1519 * At least on omap4, unused uarts may not idle after reset without 1520 * a basic scr dma configuration even with no dma in use. The 1521 * module clkctrl status bits will be 1 instead of 3 blocking idle 1522 * for the whole clockdomain. The softreset below will clear scr, 1523 * and we restore it on resume so this is safe to do on all SoCs 1524 * needing omap8250_soft_reset() quirk. Do it in two writes as 1525 * recommended in the comment for omap8250_update_scr(). 1526 */ 1527 serial_out(up, UART_OMAP_SCR, OMAP_UART_SCR_DMAMODE_1); 1528 serial_out(up, UART_OMAP_SCR, 1529 OMAP_UART_SCR_DMAMODE_1 | OMAP_UART_SCR_DMAMODE_CTL); 1530 1531 sysc = serial_in(up, UART_OMAP_SYSC); 1532 1533 /* softreset the UART */ 1534 sysc |= OMAP_UART_SYSC_SOFTRESET; 1535 serial_out(up, UART_OMAP_SYSC, sysc); 1536 1537 /* By experiments, 1us enough for reset complete on AM335x */ 1538 do { 1539 udelay(1); 1540 syss = serial_in(up, UART_OMAP_SYSS); 1541 } while (--timeout && !(syss & OMAP_UART_SYSS_RESETDONE)); 1542 1543 if (!timeout) { 1544 dev_err(dev, "timed out waiting for reset done\n"); 1545 return -ETIMEDOUT; 1546 } 1547 1548 return 0; 1549 } 1550 1551 static int omap8250_runtime_suspend(struct device *dev) 1552 { 1553 struct omap8250_priv *priv = dev_get_drvdata(dev); 1554 struct uart_8250_port *up; 1555 1556 /* In case runtime-pm tries this before we are setup */ 1557 if (!priv) 1558 return 0; 1559 1560 up = serial8250_get_port(priv->line); 1561 /* 1562 * When using 'no_console_suspend', the console UART must not be 1563 * suspended. Since driver suspend is managed by runtime suspend, 1564 * preventing runtime suspend (by returning error) will keep device 1565 * active during suspend. 1566 */ 1567 if (priv->is_suspending && !console_suspend_enabled) { 1568 if (uart_console(&up->port)) 1569 return -EBUSY; 1570 } 1571 1572 if (priv->habit & UART_ERRATA_CLOCK_DISABLE) { 1573 int ret; 1574 1575 ret = omap8250_soft_reset(dev); 1576 if (ret) 1577 return ret; 1578 1579 /* Restore to UART mode after reset (for wakeup) */ 1580 omap8250_update_mdr1(up, priv); 1581 /* Restore wakeup enable register */ 1582 serial_out(up, UART_OMAP_WER, priv->wer); 1583 } 1584 1585 if (up->dma && up->dma->rxchan) 1586 omap_8250_rx_dma_flush(up); 1587 1588 priv->latency = PM_QOS_CPU_LATENCY_DEFAULT_VALUE; 1589 schedule_work(&priv->qos_work); 1590 1591 return 0; 1592 } 1593 1594 static int omap8250_runtime_resume(struct device *dev) 1595 { 1596 struct omap8250_priv *priv = dev_get_drvdata(dev); 1597 struct uart_8250_port *up; 1598 1599 /* In case runtime-pm tries this before we are setup */ 1600 if (!priv) 1601 return 0; 1602 1603 up = serial8250_get_port(priv->line); 1604 1605 if (omap8250_lost_context(up)) 1606 omap8250_restore_regs(up); 1607 1608 if (up->dma && up->dma->rxchan && !(priv->habit & UART_HAS_EFR2)) 1609 omap_8250_rx_dma(up); 1610 1611 priv->latency = priv->calc_latency; 1612 schedule_work(&priv->qos_work); 1613 return 0; 1614 } 1615 #endif 1616 1617 #ifdef CONFIG_SERIAL_8250_OMAP_TTYO_FIXUP 1618 static int __init omap8250_console_fixup(void) 1619 { 1620 char *omap_str; 1621 char *options; 1622 u8 idx; 1623 1624 if (strstr(boot_command_line, "console=ttyS")) 1625 /* user set a ttyS based name for the console */ 1626 return 0; 1627 1628 omap_str = strstr(boot_command_line, "console=ttyO"); 1629 if (!omap_str) 1630 /* user did not set ttyO based console, so we don't care */ 1631 return 0; 1632 1633 omap_str += 12; 1634 if ('0' <= *omap_str && *omap_str <= '9') 1635 idx = *omap_str - '0'; 1636 else 1637 return 0; 1638 1639 omap_str++; 1640 if (omap_str[0] == ',') { 1641 omap_str++; 1642 options = omap_str; 1643 } else { 1644 options = NULL; 1645 } 1646 1647 add_preferred_console("ttyS", idx, options); 1648 pr_err("WARNING: Your 'console=ttyO%d' has been replaced by 'ttyS%d'\n", 1649 idx, idx); 1650 pr_err("This ensures that you still see kernel messages. Please\n"); 1651 pr_err("update your kernel commandline.\n"); 1652 return 0; 1653 } 1654 console_initcall(omap8250_console_fixup); 1655 #endif 1656 1657 static const struct dev_pm_ops omap8250_dev_pm_ops = { 1658 SET_SYSTEM_SLEEP_PM_OPS(omap8250_suspend, omap8250_resume) 1659 SET_RUNTIME_PM_OPS(omap8250_runtime_suspend, 1660 omap8250_runtime_resume, NULL) 1661 .prepare = omap8250_prepare, 1662 .complete = omap8250_complete, 1663 }; 1664 1665 static struct platform_driver omap8250_platform_driver = { 1666 .driver = { 1667 .name = "omap8250", 1668 .pm = &omap8250_dev_pm_ops, 1669 .of_match_table = omap8250_dt_ids, 1670 }, 1671 .probe = omap8250_probe, 1672 .remove = omap8250_remove, 1673 }; 1674 module_platform_driver(omap8250_platform_driver); 1675 1676 MODULE_AUTHOR("Sebastian Andrzej Siewior"); 1677 MODULE_DESCRIPTION("OMAP 8250 Driver"); 1678 MODULE_LICENSE("GPL v2"); 1679