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/atomic.h> 12 #include <linux/clk.h> 13 #include <linux/device.h> 14 #include <linux/io.h> 15 #include <linux/module.h> 16 #include <linux/serial_8250.h> 17 #include <linux/serial_reg.h> 18 #include <linux/tty_flip.h> 19 #include <linux/platform_device.h> 20 #include <linux/slab.h> 21 #include <linux/of.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 #include <linux/pm_domain.h> 32 33 #include "8250.h" 34 35 #define DEFAULT_CLK_SPEED 48000000 36 #define OMAP_UART_REGSHIFT 2 37 38 #define UART_ERRATA_i202_MDR1_ACCESS (1 << 0) 39 #define OMAP_UART_WER_HAS_TX_WAKEUP (1 << 1) 40 #define OMAP_DMA_TX_KICK (1 << 2) 41 /* 42 * See Advisory 21 in AM437x errata SPRZ408B, updated April 2015. 43 * The same errata is applicable to AM335x and DRA7x processors too. 44 */ 45 #define UART_ERRATA_CLOCK_DISABLE (1 << 3) 46 #define UART_HAS_EFR2 BIT(4) 47 #define UART_HAS_RHR_IT_DIS BIT(5) 48 #define UART_RX_TIMEOUT_QUIRK BIT(6) 49 #define UART_HAS_NATIVE_RS485 BIT(7) 50 51 #define OMAP_UART_FCR_RX_TRIG 6 52 #define OMAP_UART_FCR_TX_TRIG 4 53 54 /* SCR register bitmasks */ 55 #define OMAP_UART_SCR_RX_TRIG_GRANU1_MASK (1 << 7) 56 #define OMAP_UART_SCR_TX_TRIG_GRANU1_MASK (1 << 6) 57 #define OMAP_UART_SCR_TX_EMPTY (1 << 3) 58 #define OMAP_UART_SCR_DMAMODE_MASK (3 << 1) 59 #define OMAP_UART_SCR_DMAMODE_1 (1 << 1) 60 #define OMAP_UART_SCR_DMAMODE_CTL (1 << 0) 61 62 /* MVR register bitmasks */ 63 #define OMAP_UART_MVR_SCHEME_SHIFT 30 64 #define OMAP_UART_LEGACY_MVR_MAJ_MASK 0xf0 65 #define OMAP_UART_LEGACY_MVR_MAJ_SHIFT 4 66 #define OMAP_UART_LEGACY_MVR_MIN_MASK 0x0f 67 #define OMAP_UART_MVR_MAJ_MASK 0x700 68 #define OMAP_UART_MVR_MAJ_SHIFT 8 69 #define OMAP_UART_MVR_MIN_MASK 0x3f 70 71 /* SYSC register bitmasks */ 72 #define OMAP_UART_SYSC_SOFTRESET (1 << 1) 73 74 /* SYSS register bitmasks */ 75 #define OMAP_UART_SYSS_RESETDONE (1 << 0) 76 77 #define UART_TI752_TLR_TX 0 78 #define UART_TI752_TLR_RX 4 79 80 #define TRIGGER_TLR_MASK(x) ((x & 0x3c) >> 2) 81 #define TRIGGER_FCR_MASK(x) (x & 3) 82 83 /* Enable XON/XOFF flow control on output */ 84 #define OMAP_UART_SW_TX 0x08 85 /* Enable XON/XOFF flow control on input */ 86 #define OMAP_UART_SW_RX 0x02 87 88 #define OMAP_UART_WER_MOD_WKUP 0x7f 89 #define OMAP_UART_TX_WAKEUP_EN (1 << 7) 90 91 #define TX_TRIGGER 1 92 #define RX_TRIGGER 48 93 94 #define OMAP_UART_TCR_RESTORE(x) ((x / 4) << 4) 95 #define OMAP_UART_TCR_HALT(x) ((x / 4) << 0) 96 97 #define UART_BUILD_REVISION(x, y) (((x) << 8) | (y)) 98 99 #define OMAP_UART_REV_46 0x0406 100 #define OMAP_UART_REV_52 0x0502 101 #define OMAP_UART_REV_63 0x0603 102 103 /* Interrupt Enable Register 2 */ 104 #define UART_OMAP_IER2 0x1B 105 #define UART_OMAP_IER2_RHR_IT_DIS BIT(2) 106 107 /* Mode Definition Register 3 */ 108 #define UART_OMAP_MDR3 0x20 109 #define UART_OMAP_MDR3_DIR_POL BIT(3) 110 #define UART_OMAP_MDR3_DIR_EN BIT(4) 111 112 /* Enhanced features register 2 */ 113 #define UART_OMAP_EFR2 0x23 114 #define UART_OMAP_EFR2_TIMEOUT_BEHAVE BIT(6) 115 116 /* RX FIFO occupancy indicator */ 117 #define UART_OMAP_RX_LVL 0x19 118 119 /* 120 * Copy of the genpd flags for the console. 121 * Only used if console suspend is disabled 122 */ 123 static unsigned int genpd_flags_console; 124 125 struct omap8250_priv { 126 void __iomem *membase; 127 int line; 128 u8 habit; 129 u8 mdr1; 130 u8 mdr3; 131 u8 efr; 132 u8 scr; 133 u8 wer; 134 u8 xon; 135 u8 xoff; 136 u8 delayed_restore; 137 u16 quot; 138 139 u8 tx_trigger; 140 u8 rx_trigger; 141 atomic_t active; 142 bool is_suspending; 143 int wakeirq; 144 int wakeups_enabled; 145 u32 latency; 146 u32 calc_latency; 147 struct pm_qos_request pm_qos_request; 148 struct work_struct qos_work; 149 struct uart_8250_dma omap8250_dma; 150 spinlock_t rx_dma_lock; 151 bool rx_dma_broken; 152 bool throttled; 153 }; 154 155 struct omap8250_dma_params { 156 u32 rx_size; 157 u8 rx_trigger; 158 u8 tx_trigger; 159 }; 160 161 struct omap8250_platdata { 162 struct omap8250_dma_params *dma_params; 163 u8 habit; 164 }; 165 166 #ifdef CONFIG_SERIAL_8250_DMA 167 static void omap_8250_rx_dma_flush(struct uart_8250_port *p); 168 #else 169 static inline void omap_8250_rx_dma_flush(struct uart_8250_port *p) { } 170 #endif 171 172 static u32 uart_read(struct omap8250_priv *priv, u32 reg) 173 { 174 return readl(priv->membase + (reg << OMAP_UART_REGSHIFT)); 175 } 176 177 /* 178 * Called on runtime PM resume path from omap8250_restore_regs(), and 179 * omap8250_set_mctrl(). 180 */ 181 static void __omap8250_set_mctrl(struct uart_port *port, unsigned int mctrl) 182 { 183 struct uart_8250_port *up = up_to_u8250p(port); 184 struct omap8250_priv *priv = up->port.private_data; 185 u8 lcr; 186 187 serial8250_do_set_mctrl(port, mctrl); 188 189 if (!mctrl_gpio_to_gpiod(up->gpios, UART_GPIO_RTS)) { 190 /* 191 * Turn off autoRTS if RTS is lowered and restore autoRTS 192 * setting if RTS is raised 193 */ 194 lcr = serial_in(up, UART_LCR); 195 serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B); 196 if ((mctrl & TIOCM_RTS) && (port->status & UPSTAT_AUTORTS)) 197 priv->efr |= UART_EFR_RTS; 198 else 199 priv->efr &= ~UART_EFR_RTS; 200 serial_out(up, UART_EFR, priv->efr); 201 serial_out(up, UART_LCR, lcr); 202 } 203 } 204 205 static void omap8250_set_mctrl(struct uart_port *port, unsigned int mctrl) 206 { 207 int err; 208 209 err = pm_runtime_resume_and_get(port->dev); 210 if (err) 211 return; 212 213 __omap8250_set_mctrl(port, mctrl); 214 215 pm_runtime_mark_last_busy(port->dev); 216 pm_runtime_put_autosuspend(port->dev); 217 } 218 219 /* 220 * Work Around for Errata i202 (2430, 3430, 3630, 4430 and 4460) 221 * The access to uart register after MDR1 Access 222 * causes UART to corrupt data. 223 * 224 * Need a delay = 225 * 5 L4 clock cycles + 5 UART functional clock cycle (@48MHz = ~0.2uS) 226 * give 10 times as much 227 */ 228 static void omap_8250_mdr1_errataset(struct uart_8250_port *up, 229 struct omap8250_priv *priv) 230 { 231 serial_out(up, UART_OMAP_MDR1, priv->mdr1); 232 udelay(2); 233 serial_out(up, UART_FCR, up->fcr | UART_FCR_CLEAR_XMIT | 234 UART_FCR_CLEAR_RCVR); 235 } 236 237 static void omap_8250_get_divisor(struct uart_port *port, unsigned int baud, 238 struct omap8250_priv *priv) 239 { 240 unsigned int uartclk = port->uartclk; 241 unsigned int div_13, div_16; 242 unsigned int abs_d13, abs_d16; 243 244 /* 245 * Old custom speed handling. 246 */ 247 if (baud == 38400 && (port->flags & UPF_SPD_MASK) == UPF_SPD_CUST) { 248 priv->quot = port->custom_divisor & UART_DIV_MAX; 249 /* 250 * I assume that nobody is using this. But hey, if somebody 251 * would like to specify the divisor _and_ the mode then the 252 * driver is ready and waiting for it. 253 */ 254 if (port->custom_divisor & (1 << 16)) 255 priv->mdr1 = UART_OMAP_MDR1_13X_MODE; 256 else 257 priv->mdr1 = UART_OMAP_MDR1_16X_MODE; 258 return; 259 } 260 div_13 = DIV_ROUND_CLOSEST(uartclk, 13 * baud); 261 div_16 = DIV_ROUND_CLOSEST(uartclk, 16 * baud); 262 263 if (!div_13) 264 div_13 = 1; 265 if (!div_16) 266 div_16 = 1; 267 268 abs_d13 = abs(baud - uartclk / 13 / div_13); 269 abs_d16 = abs(baud - uartclk / 16 / div_16); 270 271 if (abs_d13 >= abs_d16) { 272 priv->mdr1 = UART_OMAP_MDR1_16X_MODE; 273 priv->quot = div_16; 274 } else { 275 priv->mdr1 = UART_OMAP_MDR1_13X_MODE; 276 priv->quot = div_13; 277 } 278 } 279 280 static void omap8250_update_scr(struct uart_8250_port *up, 281 struct omap8250_priv *priv) 282 { 283 u8 old_scr; 284 285 old_scr = serial_in(up, UART_OMAP_SCR); 286 if (old_scr == priv->scr) 287 return; 288 289 /* 290 * The manual recommends not to enable the DMA mode selector in the SCR 291 * (instead of the FCR) register _and_ selecting the DMA mode as one 292 * register write because this may lead to malfunction. 293 */ 294 if (priv->scr & OMAP_UART_SCR_DMAMODE_MASK) 295 serial_out(up, UART_OMAP_SCR, 296 priv->scr & ~OMAP_UART_SCR_DMAMODE_MASK); 297 serial_out(up, UART_OMAP_SCR, priv->scr); 298 } 299 300 static void omap8250_update_mdr1(struct uart_8250_port *up, 301 struct omap8250_priv *priv) 302 { 303 if (priv->habit & UART_ERRATA_i202_MDR1_ACCESS) 304 omap_8250_mdr1_errataset(up, priv); 305 else 306 serial_out(up, UART_OMAP_MDR1, priv->mdr1); 307 } 308 309 static void omap8250_restore_regs(struct uart_8250_port *up) 310 { 311 struct omap8250_priv *priv = up->port.private_data; 312 struct uart_8250_dma *dma = up->dma; 313 u8 mcr = serial8250_in_MCR(up); 314 315 /* Port locked to synchronize UART_IER access against the console. */ 316 lockdep_assert_held_once(&up->port.lock); 317 318 if (dma && dma->tx_running) { 319 /* 320 * TCSANOW requests the change to occur immediately however if 321 * we have a TX-DMA operation in progress then it has been 322 * observed that it might stall and never complete. Therefore we 323 * delay DMA completes to prevent this hang from happen. 324 */ 325 priv->delayed_restore = 1; 326 return; 327 } 328 329 serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B); 330 serial_out(up, UART_EFR, UART_EFR_ECB); 331 332 serial_out(up, UART_LCR, UART_LCR_CONF_MODE_A); 333 serial8250_out_MCR(up, mcr | UART_MCR_TCRTLR); 334 serial_out(up, UART_FCR, up->fcr); 335 336 omap8250_update_scr(up, priv); 337 338 serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B); 339 340 serial_out(up, UART_TI752_TCR, OMAP_UART_TCR_RESTORE(16) | 341 OMAP_UART_TCR_HALT(52)); 342 serial_out(up, UART_TI752_TLR, 343 TRIGGER_TLR_MASK(priv->tx_trigger) << UART_TI752_TLR_TX | 344 TRIGGER_TLR_MASK(priv->rx_trigger) << UART_TI752_TLR_RX); 345 346 serial_out(up, UART_LCR, 0); 347 348 /* drop TCR + TLR access, we setup XON/XOFF later */ 349 serial8250_out_MCR(up, mcr); 350 351 serial_out(up, UART_IER, up->ier); 352 353 serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B); 354 serial_dl_write(up, priv->quot); 355 356 serial_out(up, UART_EFR, priv->efr); 357 358 /* Configure flow control */ 359 serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B); 360 serial_out(up, UART_XON1, priv->xon); 361 serial_out(up, UART_XOFF1, priv->xoff); 362 363 serial_out(up, UART_LCR, up->lcr); 364 365 omap8250_update_mdr1(up, priv); 366 367 __omap8250_set_mctrl(&up->port, up->port.mctrl); 368 369 serial_out(up, UART_OMAP_MDR3, priv->mdr3); 370 371 if (up->port.rs485.flags & SER_RS485_ENABLED && 372 up->port.rs485_config == serial8250_em485_config) 373 serial8250_em485_stop_tx(up); 374 } 375 376 /* 377 * OMAP can use "CLK / (16 or 13) / div" for baud rate. And then we have have 378 * some differences in how we want to handle flow control. 379 */ 380 static void omap_8250_set_termios(struct uart_port *port, 381 struct ktermios *termios, 382 const struct ktermios *old) 383 { 384 struct uart_8250_port *up = up_to_u8250p(port); 385 struct omap8250_priv *priv = up->port.private_data; 386 unsigned char cval = 0; 387 unsigned int baud; 388 389 cval = UART_LCR_WLEN(tty_get_char_size(termios->c_cflag)); 390 391 if (termios->c_cflag & CSTOPB) 392 cval |= UART_LCR_STOP; 393 if (termios->c_cflag & PARENB) 394 cval |= UART_LCR_PARITY; 395 if (!(termios->c_cflag & PARODD)) 396 cval |= UART_LCR_EPAR; 397 if (termios->c_cflag & CMSPAR) 398 cval |= UART_LCR_SPAR; 399 400 /* 401 * Ask the core to calculate the divisor for us. 402 */ 403 baud = uart_get_baud_rate(port, termios, old, 404 port->uartclk / 16 / UART_DIV_MAX, 405 port->uartclk / 13); 406 omap_8250_get_divisor(port, baud, priv); 407 408 /* 409 * Ok, we're now changing the port state. Do it with 410 * interrupts disabled. 411 */ 412 pm_runtime_get_sync(port->dev); 413 uart_port_lock_irq(port); 414 415 /* 416 * Update the per-port timeout. 417 */ 418 uart_update_timeout(port, termios->c_cflag, baud); 419 420 up->port.read_status_mask = UART_LSR_OE | UART_LSR_THRE | UART_LSR_DR; 421 if (termios->c_iflag & INPCK) 422 up->port.read_status_mask |= UART_LSR_FE | UART_LSR_PE; 423 if (termios->c_iflag & (IGNBRK | PARMRK)) 424 up->port.read_status_mask |= UART_LSR_BI; 425 426 /* 427 * Characters to ignore 428 */ 429 up->port.ignore_status_mask = 0; 430 if (termios->c_iflag & IGNPAR) 431 up->port.ignore_status_mask |= UART_LSR_PE | UART_LSR_FE; 432 if (termios->c_iflag & IGNBRK) { 433 up->port.ignore_status_mask |= UART_LSR_BI; 434 /* 435 * If we're ignoring parity and break indicators, 436 * ignore overruns too (for real raw support). 437 */ 438 if (termios->c_iflag & IGNPAR) 439 up->port.ignore_status_mask |= UART_LSR_OE; 440 } 441 442 /* 443 * ignore all characters if CREAD is not set 444 */ 445 if ((termios->c_cflag & CREAD) == 0) 446 up->port.ignore_status_mask |= UART_LSR_DR; 447 448 /* 449 * Modem status interrupts 450 */ 451 up->ier &= ~UART_IER_MSI; 452 if (UART_ENABLE_MS(&up->port, termios->c_cflag)) 453 up->ier |= UART_IER_MSI; 454 455 up->lcr = cval; 456 /* Up to here it was mostly serial8250_do_set_termios() */ 457 458 /* 459 * We enable TRIG_GRANU for RX and TX and additionally we set 460 * SCR_TX_EMPTY bit. The result is the following: 461 * - RX_TRIGGER amount of bytes in the FIFO will cause an interrupt. 462 * - less than RX_TRIGGER number of bytes will also cause an interrupt 463 * once the UART decides that there no new bytes arriving. 464 * - Once THRE is enabled, the interrupt will be fired once the FIFO is 465 * empty - the trigger level is ignored here. 466 * 467 * Once DMA is enabled: 468 * - UART will assert the TX DMA line once there is room for TX_TRIGGER 469 * bytes in the TX FIFO. On each assert the DMA engine will move 470 * TX_TRIGGER bytes into the FIFO. 471 * - UART will assert the RX DMA line once there are RX_TRIGGER bytes in 472 * the FIFO and move RX_TRIGGER bytes. 473 * This is because threshold and trigger values are the same. 474 */ 475 up->fcr = UART_FCR_ENABLE_FIFO; 476 up->fcr |= TRIGGER_FCR_MASK(priv->tx_trigger) << OMAP_UART_FCR_TX_TRIG; 477 up->fcr |= TRIGGER_FCR_MASK(priv->rx_trigger) << OMAP_UART_FCR_RX_TRIG; 478 479 priv->scr = OMAP_UART_SCR_RX_TRIG_GRANU1_MASK | OMAP_UART_SCR_TX_EMPTY | 480 OMAP_UART_SCR_TX_TRIG_GRANU1_MASK; 481 482 if (up->dma) 483 priv->scr |= OMAP_UART_SCR_DMAMODE_1 | 484 OMAP_UART_SCR_DMAMODE_CTL; 485 486 priv->xon = termios->c_cc[VSTART]; 487 priv->xoff = termios->c_cc[VSTOP]; 488 489 priv->efr = 0; 490 up->port.status &= ~(UPSTAT_AUTOCTS | UPSTAT_AUTORTS | UPSTAT_AUTOXOFF); 491 492 if (termios->c_cflag & CRTSCTS && up->port.flags & UPF_HARD_FLOW && 493 !mctrl_gpio_to_gpiod(up->gpios, UART_GPIO_RTS) && 494 !mctrl_gpio_to_gpiod(up->gpios, UART_GPIO_CTS)) { 495 /* Enable AUTOCTS (autoRTS is enabled when RTS is raised) */ 496 up->port.status |= UPSTAT_AUTOCTS | UPSTAT_AUTORTS; 497 priv->efr |= UART_EFR_CTS; 498 } else if (up->port.flags & UPF_SOFT_FLOW) { 499 /* 500 * OMAP rx s/w flow control is borked; the transmitter remains 501 * stuck off even if rx flow control is subsequently disabled 502 */ 503 504 /* 505 * IXOFF Flag: 506 * Enable XON/XOFF flow control on output. 507 * Transmit XON1, XOFF1 508 */ 509 if (termios->c_iflag & IXOFF) { 510 up->port.status |= UPSTAT_AUTOXOFF; 511 priv->efr |= OMAP_UART_SW_TX; 512 } 513 } 514 omap8250_restore_regs(up); 515 516 uart_port_unlock_irq(&up->port); 517 pm_runtime_mark_last_busy(port->dev); 518 pm_runtime_put_autosuspend(port->dev); 519 520 /* calculate wakeup latency constraint */ 521 priv->calc_latency = USEC_PER_SEC * 64 * 8 / baud; 522 priv->latency = priv->calc_latency; 523 524 schedule_work(&priv->qos_work); 525 526 /* Don't rewrite B0 */ 527 if (tty_termios_baud_rate(termios)) 528 tty_termios_encode_baud_rate(termios, baud, baud); 529 } 530 531 /* same as 8250 except that we may have extra flow bits set in EFR */ 532 static void omap_8250_pm(struct uart_port *port, unsigned int state, 533 unsigned int oldstate) 534 { 535 struct uart_8250_port *up = up_to_u8250p(port); 536 u8 efr; 537 538 pm_runtime_get_sync(port->dev); 539 540 /* Synchronize UART_IER access against the console. */ 541 uart_port_lock_irq(port); 542 543 serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B); 544 efr = serial_in(up, UART_EFR); 545 serial_out(up, UART_EFR, efr | UART_EFR_ECB); 546 serial_out(up, UART_LCR, 0); 547 548 serial_out(up, UART_IER, (state != 0) ? UART_IERX_SLEEP : 0); 549 serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B); 550 serial_out(up, UART_EFR, efr); 551 serial_out(up, UART_LCR, 0); 552 553 uart_port_unlock_irq(port); 554 555 pm_runtime_mark_last_busy(port->dev); 556 pm_runtime_put_autosuspend(port->dev); 557 } 558 559 static void omap_serial_fill_features_erratas(struct uart_8250_port *up, 560 struct omap8250_priv *priv) 561 { 562 static const struct soc_device_attribute k3_soc_devices[] = { 563 { .family = "AM65X", }, 564 { .family = "J721E", .revision = "SR1.0" }, 565 { /* sentinel */ } 566 }; 567 u32 mvr, scheme; 568 u16 revision, major, minor; 569 570 mvr = uart_read(priv, UART_OMAP_MVER); 571 572 /* Check revision register scheme */ 573 scheme = mvr >> OMAP_UART_MVR_SCHEME_SHIFT; 574 575 switch (scheme) { 576 case 0: /* Legacy Scheme: OMAP2/3 */ 577 /* MINOR_REV[0:4], MAJOR_REV[4:7] */ 578 major = (mvr & OMAP_UART_LEGACY_MVR_MAJ_MASK) >> 579 OMAP_UART_LEGACY_MVR_MAJ_SHIFT; 580 minor = (mvr & OMAP_UART_LEGACY_MVR_MIN_MASK); 581 break; 582 case 1: 583 /* New Scheme: OMAP4+ */ 584 /* MINOR_REV[0:5], MAJOR_REV[8:10] */ 585 major = (mvr & OMAP_UART_MVR_MAJ_MASK) >> 586 OMAP_UART_MVR_MAJ_SHIFT; 587 minor = (mvr & OMAP_UART_MVR_MIN_MASK); 588 break; 589 default: 590 dev_warn(up->port.dev, 591 "Unknown revision, defaulting to highest\n"); 592 /* highest possible revision */ 593 major = 0xff; 594 minor = 0xff; 595 } 596 /* normalize revision for the driver */ 597 revision = UART_BUILD_REVISION(major, minor); 598 599 switch (revision) { 600 case OMAP_UART_REV_46: 601 priv->habit |= UART_ERRATA_i202_MDR1_ACCESS; 602 break; 603 case OMAP_UART_REV_52: 604 priv->habit |= UART_ERRATA_i202_MDR1_ACCESS | 605 OMAP_UART_WER_HAS_TX_WAKEUP; 606 break; 607 case OMAP_UART_REV_63: 608 priv->habit |= UART_ERRATA_i202_MDR1_ACCESS | 609 OMAP_UART_WER_HAS_TX_WAKEUP; 610 break; 611 default: 612 break; 613 } 614 615 /* 616 * AM65x SR1.0, AM65x SR2.0 and J721e SR1.0 don't 617 * don't have RHR_IT_DIS bit in IER2 register. So drop to flag 618 * to enable errata workaround. 619 */ 620 if (soc_device_match(k3_soc_devices)) 621 priv->habit &= ~UART_HAS_RHR_IT_DIS; 622 } 623 624 static void omap8250_uart_qos_work(struct work_struct *work) 625 { 626 struct omap8250_priv *priv; 627 628 priv = container_of(work, struct omap8250_priv, qos_work); 629 cpu_latency_qos_update_request(&priv->pm_qos_request, priv->latency); 630 } 631 632 #ifdef CONFIG_SERIAL_8250_DMA 633 static int omap_8250_dma_handle_irq(struct uart_port *port); 634 #endif 635 636 static irqreturn_t omap8250_irq(int irq, void *dev_id) 637 { 638 struct omap8250_priv *priv = dev_id; 639 struct uart_8250_port *up = serial8250_get_port(priv->line); 640 struct uart_port *port = &up->port; 641 unsigned int iir, lsr; 642 int ret; 643 644 pm_runtime_get_noresume(port->dev); 645 646 /* Shallow idle state wake-up to an IO interrupt? */ 647 if (atomic_add_unless(&priv->active, 1, 1)) { 648 priv->latency = priv->calc_latency; 649 schedule_work(&priv->qos_work); 650 } 651 652 #ifdef CONFIG_SERIAL_8250_DMA 653 if (up->dma) { 654 ret = omap_8250_dma_handle_irq(port); 655 pm_runtime_mark_last_busy(port->dev); 656 pm_runtime_put(port->dev); 657 return IRQ_RETVAL(ret); 658 } 659 #endif 660 661 lsr = serial_port_in(port, UART_LSR); 662 iir = serial_port_in(port, UART_IIR); 663 ret = serial8250_handle_irq(port, iir); 664 665 /* 666 * On K3 SoCs, it is observed that RX TIMEOUT is signalled after 667 * FIFO has been drained, in which case a dummy read of RX FIFO 668 * is required to clear RX TIMEOUT condition. 669 */ 670 if (priv->habit & UART_RX_TIMEOUT_QUIRK && 671 (iir & UART_IIR_RX_TIMEOUT) == UART_IIR_RX_TIMEOUT && 672 serial_port_in(port, UART_OMAP_RX_LVL) == 0) { 673 serial_port_in(port, UART_RX); 674 } 675 676 /* Stop processing interrupts on input overrun */ 677 if ((lsr & UART_LSR_OE) && up->overrun_backoff_time_ms > 0) { 678 unsigned long delay; 679 680 /* Synchronize UART_IER access against the console. */ 681 uart_port_lock(port); 682 up->ier = port->serial_in(port, UART_IER); 683 if (up->ier & (UART_IER_RLSI | UART_IER_RDI)) { 684 port->ops->stop_rx(port); 685 } else { 686 /* Keep restarting the timer until 687 * the input overrun subsides. 688 */ 689 cancel_delayed_work(&up->overrun_backoff); 690 } 691 uart_port_unlock(port); 692 693 delay = msecs_to_jiffies(up->overrun_backoff_time_ms); 694 schedule_delayed_work(&up->overrun_backoff, delay); 695 } 696 697 pm_runtime_mark_last_busy(port->dev); 698 pm_runtime_put(port->dev); 699 700 return IRQ_RETVAL(ret); 701 } 702 703 static int omap_8250_startup(struct uart_port *port) 704 { 705 struct uart_8250_port *up = up_to_u8250p(port); 706 struct omap8250_priv *priv = port->private_data; 707 struct uart_8250_dma *dma = &priv->omap8250_dma; 708 int ret; 709 710 if (priv->wakeirq) { 711 ret = dev_pm_set_dedicated_wake_irq(port->dev, priv->wakeirq); 712 if (ret) 713 return ret; 714 } 715 716 pm_runtime_get_sync(port->dev); 717 718 serial_out(up, UART_FCR, UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT); 719 720 serial_out(up, UART_LCR, UART_LCR_WLEN8); 721 722 up->lsr_saved_flags = 0; 723 up->msr_saved_flags = 0; 724 725 /* Disable DMA for console UART */ 726 if (dma->fn && !uart_console(port)) { 727 up->dma = &priv->omap8250_dma; 728 ret = serial8250_request_dma(up); 729 if (ret) { 730 dev_warn_ratelimited(port->dev, 731 "failed to request DMA\n"); 732 up->dma = NULL; 733 } 734 } else { 735 up->dma = NULL; 736 } 737 738 /* Synchronize UART_IER access against the console. */ 739 uart_port_lock_irq(port); 740 up->ier = UART_IER_RLSI | UART_IER_RDI; 741 serial_out(up, UART_IER, up->ier); 742 uart_port_unlock_irq(port); 743 744 #ifdef CONFIG_PM 745 up->capabilities |= UART_CAP_RPM; 746 #endif 747 748 /* Enable module level wake up */ 749 priv->wer = OMAP_UART_WER_MOD_WKUP; 750 if (priv->habit & OMAP_UART_WER_HAS_TX_WAKEUP) 751 priv->wer |= OMAP_UART_TX_WAKEUP_EN; 752 serial_out(up, UART_OMAP_WER, priv->wer); 753 754 if (up->dma && !(priv->habit & UART_HAS_EFR2)) { 755 uart_port_lock_irq(port); 756 up->dma->rx_dma(up); 757 uart_port_unlock_irq(port); 758 } 759 760 enable_irq(up->port.irq); 761 762 pm_runtime_mark_last_busy(port->dev); 763 pm_runtime_put_autosuspend(port->dev); 764 return 0; 765 } 766 767 static void omap_8250_shutdown(struct uart_port *port) 768 { 769 struct uart_8250_port *up = up_to_u8250p(port); 770 struct omap8250_priv *priv = port->private_data; 771 772 flush_work(&priv->qos_work); 773 if (up->dma) 774 omap_8250_rx_dma_flush(up); 775 776 pm_runtime_get_sync(port->dev); 777 778 serial_out(up, UART_OMAP_WER, 0); 779 if (priv->habit & UART_HAS_EFR2) 780 serial_out(up, UART_OMAP_EFR2, 0x0); 781 782 /* Synchronize UART_IER access against the console. */ 783 uart_port_lock_irq(port); 784 up->ier = 0; 785 serial_out(up, UART_IER, 0); 786 uart_port_unlock_irq(port); 787 disable_irq_nosync(up->port.irq); 788 dev_pm_clear_wake_irq(port->dev); 789 790 serial8250_release_dma(up); 791 up->dma = NULL; 792 793 /* 794 * Disable break condition and FIFOs 795 */ 796 if (up->lcr & UART_LCR_SBC) 797 serial_out(up, UART_LCR, up->lcr & ~UART_LCR_SBC); 798 serial_out(up, UART_FCR, UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT); 799 800 pm_runtime_mark_last_busy(port->dev); 801 pm_runtime_put_autosuspend(port->dev); 802 } 803 804 static void omap_8250_throttle(struct uart_port *port) 805 { 806 struct omap8250_priv *priv = port->private_data; 807 unsigned long flags; 808 809 pm_runtime_get_sync(port->dev); 810 811 uart_port_lock_irqsave(port, &flags); 812 port->ops->stop_rx(port); 813 priv->throttled = true; 814 uart_port_unlock_irqrestore(port, flags); 815 816 pm_runtime_mark_last_busy(port->dev); 817 pm_runtime_put_autosuspend(port->dev); 818 } 819 820 static void omap_8250_unthrottle(struct uart_port *port) 821 { 822 struct omap8250_priv *priv = port->private_data; 823 struct uart_8250_port *up = up_to_u8250p(port); 824 unsigned long flags; 825 826 pm_runtime_get_sync(port->dev); 827 828 /* Synchronize UART_IER access against the console. */ 829 uart_port_lock_irqsave(port, &flags); 830 priv->throttled = false; 831 if (up->dma) 832 up->dma->rx_dma(up); 833 up->ier |= UART_IER_RLSI | UART_IER_RDI; 834 port->read_status_mask |= UART_LSR_DR; 835 serial_out(up, UART_IER, up->ier); 836 uart_port_unlock_irqrestore(port, flags); 837 838 pm_runtime_mark_last_busy(port->dev); 839 pm_runtime_put_autosuspend(port->dev); 840 } 841 842 static int omap8250_rs485_config(struct uart_port *port, 843 struct ktermios *termios, 844 struct serial_rs485 *rs485) 845 { 846 struct omap8250_priv *priv = port->private_data; 847 struct uart_8250_port *up = up_to_u8250p(port); 848 u32 fixed_delay_rts_before_send = 0; 849 u32 fixed_delay_rts_after_send = 0; 850 unsigned int baud; 851 852 /* 853 * There is a fixed delay of 3 bit clock cycles after the TX shift 854 * register is going empty to allow time for the stop bit to transition 855 * through the transceiver before direction is changed to receive. 856 * 857 * Additionally there appears to be a 1 bit clock delay between writing 858 * to the THR register and transmission of the start bit, per page 8783 859 * of the AM65 TRM: https://www.ti.com/lit/ug/spruid7e/spruid7e.pdf 860 */ 861 if (priv->quot) { 862 if (priv->mdr1 == UART_OMAP_MDR1_16X_MODE) 863 baud = port->uartclk / (16 * priv->quot); 864 else 865 baud = port->uartclk / (13 * priv->quot); 866 867 fixed_delay_rts_after_send = 3 * MSEC_PER_SEC / baud; 868 fixed_delay_rts_before_send = 1 * MSEC_PER_SEC / baud; 869 } 870 871 /* 872 * Fall back to RS485 software emulation if the UART is missing 873 * hardware support, if the device tree specifies an mctrl_gpio 874 * (indicates that RTS is unavailable due to a pinmux conflict) 875 * or if the requested delays exceed the fixed hardware delays. 876 */ 877 if (!(priv->habit & UART_HAS_NATIVE_RS485) || 878 mctrl_gpio_to_gpiod(up->gpios, UART_GPIO_RTS) || 879 rs485->delay_rts_after_send > fixed_delay_rts_after_send || 880 rs485->delay_rts_before_send > fixed_delay_rts_before_send) { 881 priv->mdr3 &= ~UART_OMAP_MDR3_DIR_EN; 882 serial_out(up, UART_OMAP_MDR3, priv->mdr3); 883 884 port->rs485_config = serial8250_em485_config; 885 return serial8250_em485_config(port, termios, rs485); 886 } 887 888 rs485->delay_rts_after_send = fixed_delay_rts_after_send; 889 rs485->delay_rts_before_send = fixed_delay_rts_before_send; 890 891 if (rs485->flags & SER_RS485_ENABLED) 892 priv->mdr3 |= UART_OMAP_MDR3_DIR_EN; 893 else 894 priv->mdr3 &= ~UART_OMAP_MDR3_DIR_EN; 895 896 /* 897 * Retain same polarity semantics as RS485 software emulation, 898 * i.e. SER_RS485_RTS_ON_SEND means driving RTS low on send. 899 */ 900 if (rs485->flags & SER_RS485_RTS_ON_SEND) 901 priv->mdr3 &= ~UART_OMAP_MDR3_DIR_POL; 902 else 903 priv->mdr3 |= UART_OMAP_MDR3_DIR_POL; 904 905 serial_out(up, UART_OMAP_MDR3, priv->mdr3); 906 907 return 0; 908 } 909 910 #ifdef CONFIG_SERIAL_8250_DMA 911 static int omap_8250_rx_dma(struct uart_8250_port *p); 912 913 /* Must be called while priv->rx_dma_lock is held */ 914 static void __dma_rx_do_complete(struct uart_8250_port *p) 915 { 916 struct uart_8250_dma *dma = p->dma; 917 struct tty_port *tty_port = &p->port.state->port; 918 struct omap8250_priv *priv = p->port.private_data; 919 struct dma_chan *rxchan = dma->rxchan; 920 dma_cookie_t cookie; 921 struct dma_tx_state state; 922 int count; 923 int ret; 924 u32 reg; 925 926 if (!dma->rx_running) 927 goto out; 928 929 cookie = dma->rx_cookie; 930 dma->rx_running = 0; 931 932 /* Re-enable RX FIFO interrupt now that transfer is complete */ 933 if (priv->habit & UART_HAS_RHR_IT_DIS) { 934 reg = serial_in(p, UART_OMAP_IER2); 935 reg &= ~UART_OMAP_IER2_RHR_IT_DIS; 936 serial_out(p, UART_OMAP_IER2, reg); 937 } 938 939 dmaengine_tx_status(rxchan, cookie, &state); 940 941 count = dma->rx_size - state.residue + state.in_flight_bytes; 942 if (count < dma->rx_size) { 943 dmaengine_terminate_async(rxchan); 944 945 /* 946 * Poll for teardown to complete which guarantees in 947 * flight data is drained. 948 */ 949 if (state.in_flight_bytes) { 950 int poll_count = 25; 951 952 while (dmaengine_tx_status(rxchan, cookie, NULL) && 953 poll_count--) 954 cpu_relax(); 955 956 if (poll_count == -1) 957 dev_err(p->port.dev, "teardown incomplete\n"); 958 } 959 } 960 if (!count) 961 goto out; 962 ret = tty_insert_flip_string(tty_port, dma->rx_buf, count); 963 964 p->port.icount.rx += ret; 965 p->port.icount.buf_overrun += count - ret; 966 out: 967 968 tty_flip_buffer_push(tty_port); 969 } 970 971 static void __dma_rx_complete(void *param) 972 { 973 struct uart_8250_port *p = param; 974 struct omap8250_priv *priv = p->port.private_data; 975 struct uart_8250_dma *dma = p->dma; 976 struct dma_tx_state state; 977 unsigned long flags; 978 979 /* Synchronize UART_IER access against the console. */ 980 uart_port_lock_irqsave(&p->port, &flags); 981 982 /* 983 * If the tx status is not DMA_COMPLETE, then this is a delayed 984 * completion callback. A previous RX timeout flush would have 985 * already pushed the data, so exit. 986 */ 987 if (dmaengine_tx_status(dma->rxchan, dma->rx_cookie, &state) != 988 DMA_COMPLETE) { 989 uart_port_unlock_irqrestore(&p->port, flags); 990 return; 991 } 992 __dma_rx_do_complete(p); 993 if (!priv->throttled) { 994 p->ier |= UART_IER_RLSI | UART_IER_RDI; 995 serial_out(p, UART_IER, p->ier); 996 if (!(priv->habit & UART_HAS_EFR2)) 997 omap_8250_rx_dma(p); 998 } 999 1000 uart_port_unlock_irqrestore(&p->port, flags); 1001 } 1002 1003 static void omap_8250_rx_dma_flush(struct uart_8250_port *p) 1004 { 1005 struct omap8250_priv *priv = p->port.private_data; 1006 struct uart_8250_dma *dma = p->dma; 1007 struct dma_tx_state state; 1008 unsigned long flags; 1009 int ret; 1010 1011 spin_lock_irqsave(&priv->rx_dma_lock, flags); 1012 1013 if (!dma->rx_running) { 1014 spin_unlock_irqrestore(&priv->rx_dma_lock, flags); 1015 return; 1016 } 1017 1018 ret = dmaengine_tx_status(dma->rxchan, dma->rx_cookie, &state); 1019 if (ret == DMA_IN_PROGRESS) { 1020 ret = dmaengine_pause(dma->rxchan); 1021 if (WARN_ON_ONCE(ret)) 1022 priv->rx_dma_broken = true; 1023 } 1024 __dma_rx_do_complete(p); 1025 spin_unlock_irqrestore(&priv->rx_dma_lock, flags); 1026 } 1027 1028 static int omap_8250_rx_dma(struct uart_8250_port *p) 1029 { 1030 struct omap8250_priv *priv = p->port.private_data; 1031 struct uart_8250_dma *dma = p->dma; 1032 int err = 0; 1033 struct dma_async_tx_descriptor *desc; 1034 unsigned long flags; 1035 u32 reg; 1036 1037 /* Port locked to synchronize UART_IER access against the console. */ 1038 lockdep_assert_held_once(&p->port.lock); 1039 1040 if (priv->rx_dma_broken) 1041 return -EINVAL; 1042 1043 spin_lock_irqsave(&priv->rx_dma_lock, flags); 1044 1045 if (dma->rx_running) { 1046 enum dma_status state; 1047 1048 state = dmaengine_tx_status(dma->rxchan, dma->rx_cookie, NULL); 1049 if (state == DMA_COMPLETE) { 1050 /* 1051 * Disable RX interrupts to allow RX DMA completion 1052 * callback to run. 1053 */ 1054 p->ier &= ~(UART_IER_RLSI | UART_IER_RDI); 1055 serial_out(p, UART_IER, p->ier); 1056 } 1057 goto out; 1058 } 1059 1060 desc = dmaengine_prep_slave_single(dma->rxchan, dma->rx_addr, 1061 dma->rx_size, DMA_DEV_TO_MEM, 1062 DMA_PREP_INTERRUPT | DMA_CTRL_ACK); 1063 if (!desc) { 1064 err = -EBUSY; 1065 goto out; 1066 } 1067 1068 dma->rx_running = 1; 1069 desc->callback = __dma_rx_complete; 1070 desc->callback_param = p; 1071 1072 dma->rx_cookie = dmaengine_submit(desc); 1073 1074 /* 1075 * Disable RX FIFO interrupt while RX DMA is enabled, else 1076 * spurious interrupt may be raised when data is in the RX FIFO 1077 * but is yet to be drained by DMA. 1078 */ 1079 if (priv->habit & UART_HAS_RHR_IT_DIS) { 1080 reg = serial_in(p, UART_OMAP_IER2); 1081 reg |= UART_OMAP_IER2_RHR_IT_DIS; 1082 serial_out(p, UART_OMAP_IER2, reg); 1083 } 1084 1085 dma_async_issue_pending(dma->rxchan); 1086 out: 1087 spin_unlock_irqrestore(&priv->rx_dma_lock, flags); 1088 return err; 1089 } 1090 1091 static int omap_8250_tx_dma(struct uart_8250_port *p); 1092 1093 static void omap_8250_dma_tx_complete(void *param) 1094 { 1095 struct uart_8250_port *p = param; 1096 struct uart_8250_dma *dma = p->dma; 1097 struct circ_buf *xmit = &p->port.state->xmit; 1098 unsigned long flags; 1099 bool en_thri = false; 1100 struct omap8250_priv *priv = p->port.private_data; 1101 1102 dma_sync_single_for_cpu(dma->txchan->device->dev, dma->tx_addr, 1103 UART_XMIT_SIZE, DMA_TO_DEVICE); 1104 1105 uart_port_lock_irqsave(&p->port, &flags); 1106 1107 dma->tx_running = 0; 1108 1109 uart_xmit_advance(&p->port, dma->tx_size); 1110 1111 if (priv->delayed_restore) { 1112 priv->delayed_restore = 0; 1113 omap8250_restore_regs(p); 1114 } 1115 1116 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) 1117 uart_write_wakeup(&p->port); 1118 1119 if (!uart_circ_empty(xmit) && !uart_tx_stopped(&p->port)) { 1120 int ret; 1121 1122 ret = omap_8250_tx_dma(p); 1123 if (ret) 1124 en_thri = true; 1125 } else if (p->capabilities & UART_CAP_RPM) { 1126 en_thri = true; 1127 } 1128 1129 if (en_thri) { 1130 dma->tx_err = 1; 1131 serial8250_set_THRI(p); 1132 } 1133 1134 uart_port_unlock_irqrestore(&p->port, flags); 1135 } 1136 1137 static int omap_8250_tx_dma(struct uart_8250_port *p) 1138 { 1139 struct uart_8250_dma *dma = p->dma; 1140 struct omap8250_priv *priv = p->port.private_data; 1141 struct circ_buf *xmit = &p->port.state->xmit; 1142 struct dma_async_tx_descriptor *desc; 1143 unsigned int skip_byte = 0; 1144 int ret; 1145 1146 if (dma->tx_running) 1147 return 0; 1148 if (uart_tx_stopped(&p->port) || uart_circ_empty(xmit)) { 1149 1150 /* 1151 * Even if no data, we need to return an error for the two cases 1152 * below so serial8250_tx_chars() is invoked and properly clears 1153 * THRI and/or runtime suspend. 1154 */ 1155 if (dma->tx_err || p->capabilities & UART_CAP_RPM) { 1156 ret = -EBUSY; 1157 goto err; 1158 } 1159 serial8250_clear_THRI(p); 1160 return 0; 1161 } 1162 1163 dma->tx_size = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE); 1164 if (priv->habit & OMAP_DMA_TX_KICK) { 1165 u8 tx_lvl; 1166 1167 /* 1168 * We need to put the first byte into the FIFO in order to start 1169 * the DMA transfer. For transfers smaller than four bytes we 1170 * don't bother doing DMA at all. It seem not matter if there 1171 * are still bytes in the FIFO from the last transfer (in case 1172 * we got here directly from omap_8250_dma_tx_complete()). Bytes 1173 * leaving the FIFO seem not to trigger the DMA transfer. It is 1174 * really the byte that we put into the FIFO. 1175 * If the FIFO is already full then we most likely got here from 1176 * omap_8250_dma_tx_complete(). And this means the DMA engine 1177 * just completed its work. We don't have to wait the complete 1178 * 86us at 115200,8n1 but around 60us (not to mention lower 1179 * baudrates). So in that case we take the interrupt and try 1180 * again with an empty FIFO. 1181 */ 1182 tx_lvl = serial_in(p, UART_OMAP_TX_LVL); 1183 if (tx_lvl == p->tx_loadsz) { 1184 ret = -EBUSY; 1185 goto err; 1186 } 1187 if (dma->tx_size < 4) { 1188 ret = -EINVAL; 1189 goto err; 1190 } 1191 skip_byte = 1; 1192 } 1193 1194 desc = dmaengine_prep_slave_single(dma->txchan, 1195 dma->tx_addr + xmit->tail + skip_byte, 1196 dma->tx_size - skip_byte, DMA_MEM_TO_DEV, 1197 DMA_PREP_INTERRUPT | DMA_CTRL_ACK); 1198 if (!desc) { 1199 ret = -EBUSY; 1200 goto err; 1201 } 1202 1203 dma->tx_running = 1; 1204 1205 desc->callback = omap_8250_dma_tx_complete; 1206 desc->callback_param = p; 1207 1208 dma->tx_cookie = dmaengine_submit(desc); 1209 1210 dma_sync_single_for_device(dma->txchan->device->dev, dma->tx_addr, 1211 UART_XMIT_SIZE, DMA_TO_DEVICE); 1212 1213 dma_async_issue_pending(dma->txchan); 1214 if (dma->tx_err) 1215 dma->tx_err = 0; 1216 1217 serial8250_clear_THRI(p); 1218 if (skip_byte) 1219 serial_out(p, UART_TX, xmit->buf[xmit->tail]); 1220 return 0; 1221 err: 1222 dma->tx_err = 1; 1223 return ret; 1224 } 1225 1226 static bool handle_rx_dma(struct uart_8250_port *up, unsigned int iir) 1227 { 1228 switch (iir & 0x3f) { 1229 case UART_IIR_RLSI: 1230 case UART_IIR_RX_TIMEOUT: 1231 case UART_IIR_RDI: 1232 omap_8250_rx_dma_flush(up); 1233 return true; 1234 } 1235 return omap_8250_rx_dma(up); 1236 } 1237 1238 static u16 omap_8250_handle_rx_dma(struct uart_8250_port *up, u8 iir, u16 status) 1239 { 1240 if ((status & (UART_LSR_DR | UART_LSR_BI)) && 1241 (iir & UART_IIR_RDI)) { 1242 if (handle_rx_dma(up, iir)) { 1243 status = serial8250_rx_chars(up, status); 1244 omap_8250_rx_dma(up); 1245 } 1246 } 1247 1248 return status; 1249 } 1250 1251 static void am654_8250_handle_rx_dma(struct uart_8250_port *up, u8 iir, 1252 u16 status) 1253 { 1254 /* Port locked to synchronize UART_IER access against the console. */ 1255 lockdep_assert_held_once(&up->port.lock); 1256 1257 /* 1258 * Queue a new transfer if FIFO has data. 1259 */ 1260 if ((status & (UART_LSR_DR | UART_LSR_BI)) && 1261 (up->ier & UART_IER_RDI)) { 1262 omap_8250_rx_dma(up); 1263 serial_out(up, UART_OMAP_EFR2, UART_OMAP_EFR2_TIMEOUT_BEHAVE); 1264 } else if ((iir & 0x3f) == UART_IIR_RX_TIMEOUT) { 1265 /* 1266 * Disable RX timeout, read IIR to clear 1267 * current timeout condition, clear EFR2 to 1268 * periodic timeouts, re-enable interrupts. 1269 */ 1270 up->ier &= ~(UART_IER_RLSI | UART_IER_RDI); 1271 serial_out(up, UART_IER, up->ier); 1272 omap_8250_rx_dma_flush(up); 1273 serial_in(up, UART_IIR); 1274 serial_out(up, UART_OMAP_EFR2, 0x0); 1275 up->ier |= UART_IER_RLSI | UART_IER_RDI; 1276 serial_out(up, UART_IER, up->ier); 1277 } 1278 } 1279 1280 /* 1281 * This is mostly serial8250_handle_irq(). We have a slightly different DMA 1282 * hoook for RX/TX and need different logic for them in the ISR. Therefore we 1283 * use the default routine in the non-DMA case and this one for with DMA. 1284 */ 1285 static int omap_8250_dma_handle_irq(struct uart_port *port) 1286 { 1287 struct uart_8250_port *up = up_to_u8250p(port); 1288 struct omap8250_priv *priv = up->port.private_data; 1289 u16 status; 1290 u8 iir; 1291 1292 iir = serial_port_in(port, UART_IIR); 1293 if (iir & UART_IIR_NO_INT) { 1294 return IRQ_HANDLED; 1295 } 1296 1297 uart_port_lock(port); 1298 1299 status = serial_port_in(port, UART_LSR); 1300 1301 if ((iir & 0x3f) != UART_IIR_THRI) { 1302 if (priv->habit & UART_HAS_EFR2) 1303 am654_8250_handle_rx_dma(up, iir, status); 1304 else 1305 status = omap_8250_handle_rx_dma(up, iir, status); 1306 } 1307 1308 serial8250_modem_status(up); 1309 if (status & UART_LSR_THRE && up->dma->tx_err) { 1310 if (uart_tx_stopped(&up->port) || 1311 uart_circ_empty(&up->port.state->xmit)) { 1312 up->dma->tx_err = 0; 1313 serial8250_tx_chars(up); 1314 } else { 1315 /* 1316 * try again due to an earlier failer which 1317 * might have been resolved by now. 1318 */ 1319 if (omap_8250_tx_dma(up)) 1320 serial8250_tx_chars(up); 1321 } 1322 } 1323 1324 uart_unlock_and_check_sysrq(port); 1325 1326 return 1; 1327 } 1328 1329 static bool the_no_dma_filter_fn(struct dma_chan *chan, void *param) 1330 { 1331 return false; 1332 } 1333 1334 #else 1335 1336 static inline int omap_8250_rx_dma(struct uart_8250_port *p) 1337 { 1338 return -EINVAL; 1339 } 1340 #endif 1341 1342 static int omap8250_no_handle_irq(struct uart_port *port) 1343 { 1344 /* IRQ has not been requested but handling irq? */ 1345 WARN_ONCE(1, "Unexpected irq handling before port startup\n"); 1346 return 0; 1347 } 1348 1349 static struct omap8250_dma_params am654_dma = { 1350 .rx_size = SZ_2K, 1351 .rx_trigger = 1, 1352 .tx_trigger = TX_TRIGGER, 1353 }; 1354 1355 static struct omap8250_dma_params am33xx_dma = { 1356 .rx_size = RX_TRIGGER, 1357 .rx_trigger = RX_TRIGGER, 1358 .tx_trigger = TX_TRIGGER, 1359 }; 1360 1361 static struct omap8250_platdata am654_platdata = { 1362 .dma_params = &am654_dma, 1363 .habit = UART_HAS_EFR2 | UART_HAS_RHR_IT_DIS | 1364 UART_RX_TIMEOUT_QUIRK | UART_HAS_NATIVE_RS485, 1365 }; 1366 1367 static struct omap8250_platdata am33xx_platdata = { 1368 .dma_params = &am33xx_dma, 1369 .habit = OMAP_DMA_TX_KICK | UART_ERRATA_CLOCK_DISABLE, 1370 }; 1371 1372 static struct omap8250_platdata omap4_platdata = { 1373 .dma_params = &am33xx_dma, 1374 .habit = UART_ERRATA_CLOCK_DISABLE, 1375 }; 1376 1377 static const struct of_device_id omap8250_dt_ids[] = { 1378 { .compatible = "ti,am654-uart", .data = &am654_platdata, }, 1379 { .compatible = "ti,omap2-uart" }, 1380 { .compatible = "ti,omap3-uart" }, 1381 { .compatible = "ti,omap4-uart", .data = &omap4_platdata, }, 1382 { .compatible = "ti,am3352-uart", .data = &am33xx_platdata, }, 1383 { .compatible = "ti,am4372-uart", .data = &am33xx_platdata, }, 1384 { .compatible = "ti,dra742-uart", .data = &omap4_platdata, }, 1385 {}, 1386 }; 1387 MODULE_DEVICE_TABLE(of, omap8250_dt_ids); 1388 1389 static int omap8250_probe(struct platform_device *pdev) 1390 { 1391 struct device_node *np = pdev->dev.of_node; 1392 struct omap8250_priv *priv; 1393 const struct omap8250_platdata *pdata; 1394 struct uart_8250_port up; 1395 struct resource *regs; 1396 void __iomem *membase; 1397 int irq, ret; 1398 1399 irq = platform_get_irq(pdev, 0); 1400 if (irq < 0) 1401 return irq; 1402 1403 regs = platform_get_resource(pdev, IORESOURCE_MEM, 0); 1404 if (!regs) { 1405 dev_err(&pdev->dev, "missing registers\n"); 1406 return -EINVAL; 1407 } 1408 1409 priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); 1410 if (!priv) 1411 return -ENOMEM; 1412 1413 membase = devm_ioremap(&pdev->dev, regs->start, 1414 resource_size(regs)); 1415 if (!membase) 1416 return -ENODEV; 1417 1418 memset(&up, 0, sizeof(up)); 1419 up.port.dev = &pdev->dev; 1420 up.port.mapbase = regs->start; 1421 up.port.membase = membase; 1422 up.port.irq = irq; 1423 /* 1424 * It claims to be 16C750 compatible however it is a little different. 1425 * It has EFR and has no FCR7_64byte bit. The AFE (which it claims to 1426 * have) is enabled via EFR instead of MCR. The type is set here 8250 1427 * just to get things going. UNKNOWN does not work for a few reasons and 1428 * we don't need our own type since we don't use 8250's set_termios() 1429 * or pm callback. 1430 */ 1431 up.port.type = PORT_8250; 1432 up.port.iotype = UPIO_MEM; 1433 up.port.flags = UPF_FIXED_PORT | UPF_FIXED_TYPE | UPF_SOFT_FLOW | 1434 UPF_HARD_FLOW; 1435 up.port.private_data = priv; 1436 1437 up.port.regshift = OMAP_UART_REGSHIFT; 1438 up.port.fifosize = 64; 1439 up.tx_loadsz = 64; 1440 up.capabilities = UART_CAP_FIFO; 1441 #ifdef CONFIG_PM 1442 /* 1443 * Runtime PM is mostly transparent. However to do it right we need to a 1444 * TX empty interrupt before we can put the device to auto idle. So if 1445 * PM is not enabled we don't add that flag and can spare that one extra 1446 * interrupt in the TX path. 1447 */ 1448 up.capabilities |= UART_CAP_RPM; 1449 #endif 1450 up.port.set_termios = omap_8250_set_termios; 1451 up.port.set_mctrl = omap8250_set_mctrl; 1452 up.port.pm = omap_8250_pm; 1453 up.port.startup = omap_8250_startup; 1454 up.port.shutdown = omap_8250_shutdown; 1455 up.port.throttle = omap_8250_throttle; 1456 up.port.unthrottle = omap_8250_unthrottle; 1457 up.port.rs485_config = omap8250_rs485_config; 1458 /* same rs485_supported for software emulation and native RS485 */ 1459 up.port.rs485_supported = serial8250_em485_supported; 1460 up.rs485_start_tx = serial8250_em485_start_tx; 1461 up.rs485_stop_tx = serial8250_em485_stop_tx; 1462 up.port.has_sysrq = IS_ENABLED(CONFIG_SERIAL_8250_CONSOLE); 1463 1464 ret = of_alias_get_id(np, "serial"); 1465 if (ret < 0) { 1466 dev_err(&pdev->dev, "failed to get alias\n"); 1467 return ret; 1468 } 1469 up.port.line = ret; 1470 1471 if (of_property_read_u32(np, "clock-frequency", &up.port.uartclk)) { 1472 struct clk *clk; 1473 1474 clk = devm_clk_get(&pdev->dev, NULL); 1475 if (IS_ERR(clk)) { 1476 if (PTR_ERR(clk) == -EPROBE_DEFER) 1477 return -EPROBE_DEFER; 1478 } else { 1479 up.port.uartclk = clk_get_rate(clk); 1480 } 1481 } 1482 1483 if (of_property_read_u32(np, "overrun-throttle-ms", 1484 &up.overrun_backoff_time_ms) != 0) 1485 up.overrun_backoff_time_ms = 0; 1486 1487 pdata = of_device_get_match_data(&pdev->dev); 1488 if (pdata) 1489 priv->habit |= pdata->habit; 1490 1491 if (!up.port.uartclk) { 1492 up.port.uartclk = DEFAULT_CLK_SPEED; 1493 dev_warn(&pdev->dev, 1494 "No clock speed specified: using default: %d\n", 1495 DEFAULT_CLK_SPEED); 1496 } 1497 1498 priv->membase = membase; 1499 priv->line = -ENODEV; 1500 priv->latency = PM_QOS_CPU_LATENCY_DEFAULT_VALUE; 1501 priv->calc_latency = PM_QOS_CPU_LATENCY_DEFAULT_VALUE; 1502 cpu_latency_qos_add_request(&priv->pm_qos_request, priv->latency); 1503 INIT_WORK(&priv->qos_work, omap8250_uart_qos_work); 1504 1505 spin_lock_init(&priv->rx_dma_lock); 1506 1507 platform_set_drvdata(pdev, priv); 1508 1509 device_init_wakeup(&pdev->dev, true); 1510 pm_runtime_enable(&pdev->dev); 1511 pm_runtime_use_autosuspend(&pdev->dev); 1512 1513 /* 1514 * Disable runtime PM until autosuspend delay unless specifically 1515 * enabled by the user via sysfs. This is the historic way to 1516 * prevent an unsafe default policy with lossy characters on wake-up. 1517 * For serdev devices this is not needed, the policy can be managed by 1518 * the serdev driver. 1519 */ 1520 if (!of_get_available_child_count(pdev->dev.of_node)) 1521 pm_runtime_set_autosuspend_delay(&pdev->dev, -1); 1522 1523 pm_runtime_get_sync(&pdev->dev); 1524 1525 omap_serial_fill_features_erratas(&up, priv); 1526 up.port.handle_irq = omap8250_no_handle_irq; 1527 priv->rx_trigger = RX_TRIGGER; 1528 priv->tx_trigger = TX_TRIGGER; 1529 #ifdef CONFIG_SERIAL_8250_DMA 1530 /* 1531 * Oh DMA support. If there are no DMA properties in the DT then 1532 * we will fall back to a generic DMA channel which does not 1533 * really work here. To ensure that we do not get a generic DMA 1534 * channel assigned, we have the the_no_dma_filter_fn() here. 1535 * To avoid "failed to request DMA" messages we check for DMA 1536 * properties in DT. 1537 */ 1538 ret = of_property_count_strings(np, "dma-names"); 1539 if (ret == 2) { 1540 struct omap8250_dma_params *dma_params = NULL; 1541 struct uart_8250_dma *dma = &priv->omap8250_dma; 1542 1543 dma->fn = the_no_dma_filter_fn; 1544 dma->tx_dma = omap_8250_tx_dma; 1545 dma->rx_dma = omap_8250_rx_dma; 1546 if (pdata) 1547 dma_params = pdata->dma_params; 1548 1549 if (dma_params) { 1550 dma->rx_size = dma_params->rx_size; 1551 dma->rxconf.src_maxburst = dma_params->rx_trigger; 1552 dma->txconf.dst_maxburst = dma_params->tx_trigger; 1553 priv->rx_trigger = dma_params->rx_trigger; 1554 priv->tx_trigger = dma_params->tx_trigger; 1555 } else { 1556 dma->rx_size = RX_TRIGGER; 1557 dma->rxconf.src_maxburst = RX_TRIGGER; 1558 dma->txconf.dst_maxburst = TX_TRIGGER; 1559 } 1560 } 1561 #endif 1562 1563 irq_set_status_flags(irq, IRQ_NOAUTOEN); 1564 ret = devm_request_irq(&pdev->dev, irq, omap8250_irq, 0, 1565 dev_name(&pdev->dev), priv); 1566 if (ret < 0) 1567 return ret; 1568 1569 priv->wakeirq = irq_of_parse_and_map(np, 1); 1570 1571 ret = serial8250_register_8250_port(&up); 1572 if (ret < 0) { 1573 dev_err(&pdev->dev, "unable to register 8250 port\n"); 1574 goto err; 1575 } 1576 priv->line = ret; 1577 pm_runtime_mark_last_busy(&pdev->dev); 1578 pm_runtime_put_autosuspend(&pdev->dev); 1579 return 0; 1580 err: 1581 pm_runtime_dont_use_autosuspend(&pdev->dev); 1582 pm_runtime_put_sync(&pdev->dev); 1583 flush_work(&priv->qos_work); 1584 pm_runtime_disable(&pdev->dev); 1585 cpu_latency_qos_remove_request(&priv->pm_qos_request); 1586 return ret; 1587 } 1588 1589 static int omap8250_remove(struct platform_device *pdev) 1590 { 1591 struct omap8250_priv *priv = platform_get_drvdata(pdev); 1592 struct uart_8250_port *up; 1593 int err; 1594 1595 err = pm_runtime_resume_and_get(&pdev->dev); 1596 if (err) 1597 return err; 1598 1599 up = serial8250_get_port(priv->line); 1600 omap_8250_shutdown(&up->port); 1601 serial8250_unregister_port(priv->line); 1602 priv->line = -ENODEV; 1603 pm_runtime_dont_use_autosuspend(&pdev->dev); 1604 pm_runtime_put_sync(&pdev->dev); 1605 flush_work(&priv->qos_work); 1606 pm_runtime_disable(&pdev->dev); 1607 cpu_latency_qos_remove_request(&priv->pm_qos_request); 1608 device_init_wakeup(&pdev->dev, false); 1609 return 0; 1610 } 1611 1612 static int omap8250_prepare(struct device *dev) 1613 { 1614 struct omap8250_priv *priv = dev_get_drvdata(dev); 1615 1616 if (!priv) 1617 return 0; 1618 priv->is_suspending = true; 1619 return 0; 1620 } 1621 1622 static void omap8250_complete(struct device *dev) 1623 { 1624 struct omap8250_priv *priv = dev_get_drvdata(dev); 1625 1626 if (!priv) 1627 return; 1628 priv->is_suspending = false; 1629 } 1630 1631 static int omap8250_suspend(struct device *dev) 1632 { 1633 struct omap8250_priv *priv = dev_get_drvdata(dev); 1634 struct uart_8250_port *up = serial8250_get_port(priv->line); 1635 struct generic_pm_domain *genpd = pd_to_genpd(dev->pm_domain); 1636 int err = 0; 1637 1638 serial8250_suspend_port(priv->line); 1639 1640 err = pm_runtime_resume_and_get(dev); 1641 if (err) 1642 return err; 1643 if (!device_may_wakeup(dev)) 1644 priv->wer = 0; 1645 serial_out(up, UART_OMAP_WER, priv->wer); 1646 if (uart_console(&up->port)) { 1647 if (console_suspend_enabled) 1648 err = pm_runtime_force_suspend(dev); 1649 else { 1650 /* 1651 * The pd shall not be powered-off (no console suspend). 1652 * Make copy of genpd flags before to set it always on. 1653 * The original value is restored during the resume. 1654 */ 1655 genpd_flags_console = genpd->flags; 1656 genpd->flags |= GENPD_FLAG_ALWAYS_ON; 1657 } 1658 } 1659 flush_work(&priv->qos_work); 1660 1661 return err; 1662 } 1663 1664 static int omap8250_resume(struct device *dev) 1665 { 1666 struct omap8250_priv *priv = dev_get_drvdata(dev); 1667 struct uart_8250_port *up = serial8250_get_port(priv->line); 1668 struct generic_pm_domain *genpd = pd_to_genpd(dev->pm_domain); 1669 int err; 1670 1671 if (uart_console(&up->port) && console_suspend_enabled) { 1672 if (console_suspend_enabled) { 1673 err = pm_runtime_force_resume(dev); 1674 if (err) 1675 return err; 1676 } else 1677 genpd->flags = genpd_flags_console; 1678 } 1679 1680 serial8250_resume_port(priv->line); 1681 /* Paired with pm_runtime_resume_and_get() in omap8250_suspend() */ 1682 pm_runtime_mark_last_busy(dev); 1683 pm_runtime_put_autosuspend(dev); 1684 1685 return 0; 1686 } 1687 1688 static int omap8250_lost_context(struct uart_8250_port *up) 1689 { 1690 u32 val; 1691 1692 val = serial_in(up, UART_OMAP_SCR); 1693 /* 1694 * If we lose context, then SCR is set to its reset value of zero. 1695 * After set_termios() we set bit 3 of SCR (TX_EMPTY_CTL_IT) to 1, 1696 * among other bits, to never set the register back to zero again. 1697 */ 1698 if (!val) 1699 return 1; 1700 return 0; 1701 } 1702 1703 static void uart_write(struct omap8250_priv *priv, u32 reg, u32 val) 1704 { 1705 writel(val, priv->membase + (reg << OMAP_UART_REGSHIFT)); 1706 } 1707 1708 /* TODO: in future, this should happen via API in drivers/reset/ */ 1709 static int omap8250_soft_reset(struct device *dev) 1710 { 1711 struct omap8250_priv *priv = dev_get_drvdata(dev); 1712 int timeout = 100; 1713 int sysc; 1714 int syss; 1715 1716 /* 1717 * At least on omap4, unused uarts may not idle after reset without 1718 * a basic scr dma configuration even with no dma in use. The 1719 * module clkctrl status bits will be 1 instead of 3 blocking idle 1720 * for the whole clockdomain. The softreset below will clear scr, 1721 * and we restore it on resume so this is safe to do on all SoCs 1722 * needing omap8250_soft_reset() quirk. Do it in two writes as 1723 * recommended in the comment for omap8250_update_scr(). 1724 */ 1725 uart_write(priv, UART_OMAP_SCR, OMAP_UART_SCR_DMAMODE_1); 1726 uart_write(priv, UART_OMAP_SCR, 1727 OMAP_UART_SCR_DMAMODE_1 | OMAP_UART_SCR_DMAMODE_CTL); 1728 1729 sysc = uart_read(priv, UART_OMAP_SYSC); 1730 1731 /* softreset the UART */ 1732 sysc |= OMAP_UART_SYSC_SOFTRESET; 1733 uart_write(priv, UART_OMAP_SYSC, sysc); 1734 1735 /* By experiments, 1us enough for reset complete on AM335x */ 1736 do { 1737 udelay(1); 1738 syss = uart_read(priv, UART_OMAP_SYSS); 1739 } while (--timeout && !(syss & OMAP_UART_SYSS_RESETDONE)); 1740 1741 if (!timeout) { 1742 dev_err(dev, "timed out waiting for reset done\n"); 1743 return -ETIMEDOUT; 1744 } 1745 1746 return 0; 1747 } 1748 1749 static int omap8250_runtime_suspend(struct device *dev) 1750 { 1751 struct omap8250_priv *priv = dev_get_drvdata(dev); 1752 struct uart_8250_port *up = NULL; 1753 1754 if (priv->line >= 0) 1755 up = serial8250_get_port(priv->line); 1756 1757 if (priv->habit & UART_ERRATA_CLOCK_DISABLE) { 1758 int ret; 1759 1760 ret = omap8250_soft_reset(dev); 1761 if (ret) 1762 return ret; 1763 1764 if (up) { 1765 /* Restore to UART mode after reset (for wakeup) */ 1766 omap8250_update_mdr1(up, priv); 1767 /* Restore wakeup enable register */ 1768 serial_out(up, UART_OMAP_WER, priv->wer); 1769 } 1770 } 1771 1772 if (up && up->dma && up->dma->rxchan) 1773 omap_8250_rx_dma_flush(up); 1774 1775 priv->latency = PM_QOS_CPU_LATENCY_DEFAULT_VALUE; 1776 schedule_work(&priv->qos_work); 1777 atomic_set(&priv->active, 0); 1778 1779 return 0; 1780 } 1781 1782 static int omap8250_runtime_resume(struct device *dev) 1783 { 1784 struct omap8250_priv *priv = dev_get_drvdata(dev); 1785 struct uart_8250_port *up = NULL; 1786 1787 /* Did the hardware wake to a device IO interrupt before a wakeirq? */ 1788 if (atomic_read(&priv->active)) 1789 return 0; 1790 1791 if (priv->line >= 0) 1792 up = serial8250_get_port(priv->line); 1793 1794 if (up && omap8250_lost_context(up)) { 1795 uart_port_lock_irq(&up->port); 1796 omap8250_restore_regs(up); 1797 uart_port_unlock_irq(&up->port); 1798 } 1799 1800 if (up && up->dma && up->dma->rxchan && !(priv->habit & UART_HAS_EFR2)) { 1801 uart_port_lock_irq(&up->port); 1802 omap_8250_rx_dma(up); 1803 uart_port_unlock_irq(&up->port); 1804 } 1805 1806 atomic_set(&priv->active, 1); 1807 priv->latency = priv->calc_latency; 1808 schedule_work(&priv->qos_work); 1809 1810 return 0; 1811 } 1812 1813 #ifdef CONFIG_SERIAL_8250_OMAP_TTYO_FIXUP 1814 static int __init omap8250_console_fixup(void) 1815 { 1816 char *omap_str; 1817 char *options; 1818 u8 idx; 1819 1820 if (strstr(boot_command_line, "console=ttyS")) 1821 /* user set a ttyS based name for the console */ 1822 return 0; 1823 1824 omap_str = strstr(boot_command_line, "console=ttyO"); 1825 if (!omap_str) 1826 /* user did not set ttyO based console, so we don't care */ 1827 return 0; 1828 1829 omap_str += 12; 1830 if ('0' <= *omap_str && *omap_str <= '9') 1831 idx = *omap_str - '0'; 1832 else 1833 return 0; 1834 1835 omap_str++; 1836 if (omap_str[0] == ',') { 1837 omap_str++; 1838 options = omap_str; 1839 } else { 1840 options = NULL; 1841 } 1842 1843 add_preferred_console("ttyS", idx, options); 1844 pr_err("WARNING: Your 'console=ttyO%d' has been replaced by 'ttyS%d'\n", 1845 idx, idx); 1846 pr_err("This ensures that you still see kernel messages. Please\n"); 1847 pr_err("update your kernel commandline.\n"); 1848 return 0; 1849 } 1850 console_initcall(omap8250_console_fixup); 1851 #endif 1852 1853 static const struct dev_pm_ops omap8250_dev_pm_ops = { 1854 SYSTEM_SLEEP_PM_OPS(omap8250_suspend, omap8250_resume) 1855 RUNTIME_PM_OPS(omap8250_runtime_suspend, 1856 omap8250_runtime_resume, NULL) 1857 .prepare = pm_sleep_ptr(omap8250_prepare), 1858 .complete = pm_sleep_ptr(omap8250_complete), 1859 }; 1860 1861 static struct platform_driver omap8250_platform_driver = { 1862 .driver = { 1863 .name = "omap8250", 1864 .pm = pm_ptr(&omap8250_dev_pm_ops), 1865 .of_match_table = omap8250_dt_ids, 1866 }, 1867 .probe = omap8250_probe, 1868 .remove = omap8250_remove, 1869 }; 1870 module_platform_driver(omap8250_platform_driver); 1871 1872 MODULE_AUTHOR("Sebastian Andrzej Siewior"); 1873 MODULE_DESCRIPTION("OMAP 8250 Driver"); 1874 MODULE_LICENSE("GPL v2"); 1875