1 // SPDX-License-Identifier: GPL-2.0+ 2 /* 3 * Cadence UART driver (found in Xilinx Zynq) 4 * 5 * Copyright (c) 2011 - 2014 Xilinx, Inc. 6 * 7 * This driver has originally been pushed by Xilinx using a Zynq-branding. This 8 * still shows in the naming of this file, the kconfig symbols and some symbols 9 * in the code. 10 */ 11 12 #include <linux/platform_device.h> 13 #include <linux/serial.h> 14 #include <linux/console.h> 15 #include <linux/serial_core.h> 16 #include <linux/slab.h> 17 #include <linux/tty.h> 18 #include <linux/tty_flip.h> 19 #include <linux/clk.h> 20 #include <linux/irq.h> 21 #include <linux/io.h> 22 #include <linux/of.h> 23 #include <linux/module.h> 24 #include <linux/pm_runtime.h> 25 #include <linux/iopoll.h> 26 27 #define CDNS_UART_TTY_NAME "ttyPS" 28 #define CDNS_UART_NAME "xuartps" 29 #define CDNS_UART_MAJOR 0 /* use dynamic node allocation */ 30 #define CDNS_UART_MINOR 0 /* works best with devtmpfs */ 31 #define CDNS_UART_NR_PORTS 16 32 #define CDNS_UART_FIFO_SIZE 64 /* FIFO size */ 33 #define CDNS_UART_REGISTER_SPACE 0x1000 34 #define TX_TIMEOUT 500000 35 36 /* Rx Trigger level */ 37 static int rx_trigger_level = 56; 38 module_param(rx_trigger_level, uint, 0444); 39 MODULE_PARM_DESC(rx_trigger_level, "Rx trigger level, 1-63 bytes"); 40 41 /* Rx Timeout */ 42 static int rx_timeout = 10; 43 module_param(rx_timeout, uint, 0444); 44 MODULE_PARM_DESC(rx_timeout, "Rx timeout, 1-255"); 45 46 /* Register offsets for the UART. */ 47 #define CDNS_UART_CR 0x00 /* Control Register */ 48 #define CDNS_UART_MR 0x04 /* Mode Register */ 49 #define CDNS_UART_IER 0x08 /* Interrupt Enable */ 50 #define CDNS_UART_IDR 0x0C /* Interrupt Disable */ 51 #define CDNS_UART_IMR 0x10 /* Interrupt Mask */ 52 #define CDNS_UART_ISR 0x14 /* Interrupt Status */ 53 #define CDNS_UART_BAUDGEN 0x18 /* Baud Rate Generator */ 54 #define CDNS_UART_RXTOUT 0x1C /* RX Timeout */ 55 #define CDNS_UART_RXWM 0x20 /* RX FIFO Trigger Level */ 56 #define CDNS_UART_MODEMCR 0x24 /* Modem Control */ 57 #define CDNS_UART_MODEMSR 0x28 /* Modem Status */ 58 #define CDNS_UART_SR 0x2C /* Channel Status */ 59 #define CDNS_UART_FIFO 0x30 /* FIFO */ 60 #define CDNS_UART_BAUDDIV 0x34 /* Baud Rate Divider */ 61 #define CDNS_UART_FLOWDEL 0x38 /* Flow Delay */ 62 #define CDNS_UART_IRRX_PWIDTH 0x3C /* IR Min Received Pulse Width */ 63 #define CDNS_UART_IRTX_PWIDTH 0x40 /* IR Transmitted pulse Width */ 64 #define CDNS_UART_TXWM 0x44 /* TX FIFO Trigger Level */ 65 #define CDNS_UART_RXBS 0x48 /* RX FIFO byte status register */ 66 67 /* Control Register Bit Definitions */ 68 #define CDNS_UART_CR_STOPBRK 0x00000100 /* Stop TX break */ 69 #define CDNS_UART_CR_STARTBRK 0x00000080 /* Set TX break */ 70 #define CDNS_UART_CR_TX_DIS 0x00000020 /* TX disabled. */ 71 #define CDNS_UART_CR_TX_EN 0x00000010 /* TX enabled */ 72 #define CDNS_UART_CR_RX_DIS 0x00000008 /* RX disabled. */ 73 #define CDNS_UART_CR_RX_EN 0x00000004 /* RX enabled */ 74 #define CDNS_UART_CR_TXRST 0x00000002 /* TX logic reset */ 75 #define CDNS_UART_CR_RXRST 0x00000001 /* RX logic reset */ 76 #define CDNS_UART_CR_RST_TO 0x00000040 /* Restart Timeout Counter */ 77 #define CDNS_UART_RXBS_PARITY 0x00000001 /* Parity error status */ 78 #define CDNS_UART_RXBS_FRAMING 0x00000002 /* Framing error status */ 79 #define CDNS_UART_RXBS_BRK 0x00000004 /* Overrun error status */ 80 81 /* 82 * Mode Register: 83 * The mode register (MR) defines the mode of transfer as well as the data 84 * format. If this register is modified during transmission or reception, 85 * data validity cannot be guaranteed. 86 */ 87 #define CDNS_UART_MR_CLKSEL 0x00000001 /* Pre-scalar selection */ 88 #define CDNS_UART_MR_CHMODE_L_LOOP 0x00000200 /* Local loop back mode */ 89 #define CDNS_UART_MR_CHMODE_NORM 0x00000000 /* Normal mode */ 90 #define CDNS_UART_MR_CHMODE_MASK 0x00000300 /* Mask for mode bits */ 91 92 #define CDNS_UART_MR_STOPMODE_2_BIT 0x00000080 /* 2 stop bits */ 93 #define CDNS_UART_MR_STOPMODE_1_BIT 0x00000000 /* 1 stop bit */ 94 95 #define CDNS_UART_MR_PARITY_NONE 0x00000020 /* No parity mode */ 96 #define CDNS_UART_MR_PARITY_MARK 0x00000018 /* Mark parity mode */ 97 #define CDNS_UART_MR_PARITY_SPACE 0x00000010 /* Space parity mode */ 98 #define CDNS_UART_MR_PARITY_ODD 0x00000008 /* Odd parity mode */ 99 #define CDNS_UART_MR_PARITY_EVEN 0x00000000 /* Even parity mode */ 100 101 #define CDNS_UART_MR_CHARLEN_6_BIT 0x00000006 /* 6 bits data */ 102 #define CDNS_UART_MR_CHARLEN_7_BIT 0x00000004 /* 7 bits data */ 103 #define CDNS_UART_MR_CHARLEN_8_BIT 0x00000000 /* 8 bits data */ 104 105 /* 106 * Interrupt Registers: 107 * Interrupt control logic uses the interrupt enable register (IER) and the 108 * interrupt disable register (IDR) to set the value of the bits in the 109 * interrupt mask register (IMR). The IMR determines whether to pass an 110 * interrupt to the interrupt status register (ISR). 111 * Writing a 1 to IER Enables an interrupt, writing a 1 to IDR disables an 112 * interrupt. IMR and ISR are read only, and IER and IDR are write only. 113 * Reading either IER or IDR returns 0x00. 114 * All four registers have the same bit definitions. 115 */ 116 #define CDNS_UART_IXR_TOUT 0x00000100 /* RX Timeout error interrupt */ 117 #define CDNS_UART_IXR_PARITY 0x00000080 /* Parity error interrupt */ 118 #define CDNS_UART_IXR_FRAMING 0x00000040 /* Framing error interrupt */ 119 #define CDNS_UART_IXR_OVERRUN 0x00000020 /* Overrun error interrupt */ 120 #define CDNS_UART_IXR_TXFULL 0x00000010 /* TX FIFO Full interrupt */ 121 #define CDNS_UART_IXR_TXEMPTY 0x00000008 /* TX FIFO empty interrupt */ 122 #define CDNS_UART_ISR_RXEMPTY 0x00000002 /* RX FIFO empty interrupt */ 123 #define CDNS_UART_IXR_RXTRIG 0x00000001 /* RX FIFO trigger interrupt */ 124 #define CDNS_UART_IXR_RXFULL 0x00000004 /* RX FIFO full interrupt. */ 125 #define CDNS_UART_IXR_RXEMPTY 0x00000002 /* RX FIFO empty interrupt. */ 126 #define CDNS_UART_IXR_RXMASK 0x000021e7 /* Valid RX bit mask */ 127 128 /* 129 * Do not enable parity error interrupt for the following 130 * reason: When parity error interrupt is enabled, each Rx 131 * parity error always results in 2 events. The first one 132 * being parity error interrupt and the second one with a 133 * proper Rx interrupt with the incoming data. Disabling 134 * parity error interrupt ensures better handling of parity 135 * error events. With this change, for a parity error case, we 136 * get a Rx interrupt with parity error set in ISR register 137 * and we still handle parity errors in the desired way. 138 */ 139 140 #define CDNS_UART_RX_IRQS (CDNS_UART_IXR_FRAMING | \ 141 CDNS_UART_IXR_OVERRUN | \ 142 CDNS_UART_IXR_RXTRIG | \ 143 CDNS_UART_IXR_TOUT) 144 145 /* Goes in read_status_mask for break detection as the HW doesn't do it*/ 146 #define CDNS_UART_IXR_BRK 0x00002000 147 148 #define CDNS_UART_RXBS_SUPPORT BIT(1) 149 /* 150 * Modem Control register: 151 * The read/write Modem Control register controls the interface with the modem 152 * or data set, or a peripheral device emulating a modem. 153 */ 154 #define CDNS_UART_MODEMCR_FCM 0x00000020 /* Automatic flow control mode */ 155 #define CDNS_UART_MODEMCR_RTS 0x00000002 /* Request to send output control */ 156 #define CDNS_UART_MODEMCR_DTR 0x00000001 /* Data Terminal Ready */ 157 158 /* 159 * Modem Status register: 160 * The read/write Modem Status register reports the interface with the modem 161 * or data set, or a peripheral device emulating a modem. 162 */ 163 #define CDNS_UART_MODEMSR_DCD BIT(7) /* Data Carrier Detect */ 164 #define CDNS_UART_MODEMSR_RI BIT(6) /* Ting Indicator */ 165 #define CDNS_UART_MODEMSR_DSR BIT(5) /* Data Set Ready */ 166 #define CDNS_UART_MODEMSR_CTS BIT(4) /* Clear To Send */ 167 168 /* 169 * Channel Status Register: 170 * The channel status register (CSR) is provided to enable the control logic 171 * to monitor the status of bits in the channel interrupt status register, 172 * even if these are masked out by the interrupt mask register. 173 */ 174 #define CDNS_UART_SR_RXEMPTY 0x00000002 /* RX FIFO empty */ 175 #define CDNS_UART_SR_TXEMPTY 0x00000008 /* TX FIFO empty */ 176 #define CDNS_UART_SR_TXFULL 0x00000010 /* TX FIFO full */ 177 #define CDNS_UART_SR_RXTRIG 0x00000001 /* Rx Trigger */ 178 #define CDNS_UART_SR_TACTIVE 0x00000800 /* TX state machine active */ 179 180 /* baud dividers min/max values */ 181 #define CDNS_UART_BDIV_MIN 4 182 #define CDNS_UART_BDIV_MAX 255 183 #define CDNS_UART_CD_MAX 65535 184 #define UART_AUTOSUSPEND_TIMEOUT 3000 185 186 /** 187 * struct cdns_uart - device data 188 * @port: Pointer to the UART port 189 * @uartclk: Reference clock 190 * @pclk: APB clock 191 * @cdns_uart_driver: Pointer to UART driver 192 * @baud: Current baud rate 193 * @clk_rate_change_nb: Notifier block for clock changes 194 * @quirks: Flags for RXBS support. 195 * @cts_override: Modem control state override 196 */ 197 struct cdns_uart { 198 struct uart_port *port; 199 struct clk *uartclk; 200 struct clk *pclk; 201 struct uart_driver *cdns_uart_driver; 202 unsigned int baud; 203 struct notifier_block clk_rate_change_nb; 204 u32 quirks; 205 bool cts_override; 206 }; 207 struct cdns_platform_data { 208 u32 quirks; 209 }; 210 #define to_cdns_uart(_nb) container_of(_nb, struct cdns_uart, \ 211 clk_rate_change_nb) 212 213 /** 214 * cdns_uart_handle_rx - Handle the received bytes along with Rx errors. 215 * @dev_id: Id of the UART port 216 * @isrstatus: The interrupt status register value as read 217 * Return: None 218 */ 219 static void cdns_uart_handle_rx(void *dev_id, unsigned int isrstatus) 220 { 221 struct uart_port *port = (struct uart_port *)dev_id; 222 struct cdns_uart *cdns_uart = port->private_data; 223 unsigned int data; 224 unsigned int rxbs_status = 0; 225 unsigned int status_mask; 226 unsigned int framerrprocessed = 0; 227 char status = TTY_NORMAL; 228 bool is_rxbs_support; 229 230 is_rxbs_support = cdns_uart->quirks & CDNS_UART_RXBS_SUPPORT; 231 232 while ((readl(port->membase + CDNS_UART_SR) & 233 CDNS_UART_SR_RXEMPTY) != CDNS_UART_SR_RXEMPTY) { 234 if (is_rxbs_support) 235 rxbs_status = readl(port->membase + CDNS_UART_RXBS); 236 data = readl(port->membase + CDNS_UART_FIFO); 237 port->icount.rx++; 238 /* 239 * There is no hardware break detection in Zynq, so we interpret 240 * framing error with all-zeros data as a break sequence. 241 * Most of the time, there's another non-zero byte at the 242 * end of the sequence. 243 */ 244 if (!is_rxbs_support && (isrstatus & CDNS_UART_IXR_FRAMING)) { 245 if (!data) { 246 port->read_status_mask |= CDNS_UART_IXR_BRK; 247 framerrprocessed = 1; 248 continue; 249 } 250 } 251 if (is_rxbs_support && (rxbs_status & CDNS_UART_RXBS_BRK)) { 252 port->icount.brk++; 253 status = TTY_BREAK; 254 if (uart_handle_break(port)) 255 continue; 256 } 257 258 isrstatus &= port->read_status_mask; 259 isrstatus &= ~port->ignore_status_mask; 260 status_mask = port->read_status_mask; 261 status_mask &= ~port->ignore_status_mask; 262 263 if (data && 264 (port->read_status_mask & CDNS_UART_IXR_BRK)) { 265 port->read_status_mask &= ~CDNS_UART_IXR_BRK; 266 port->icount.brk++; 267 if (uart_handle_break(port)) 268 continue; 269 } 270 271 if (uart_handle_sysrq_char(port, data)) 272 continue; 273 274 if (is_rxbs_support) { 275 if ((rxbs_status & CDNS_UART_RXBS_PARITY) 276 && (status_mask & CDNS_UART_IXR_PARITY)) { 277 port->icount.parity++; 278 status = TTY_PARITY; 279 } 280 if ((rxbs_status & CDNS_UART_RXBS_FRAMING) 281 && (status_mask & CDNS_UART_IXR_PARITY)) { 282 port->icount.frame++; 283 status = TTY_FRAME; 284 } 285 } else { 286 if (isrstatus & CDNS_UART_IXR_PARITY) { 287 port->icount.parity++; 288 status = TTY_PARITY; 289 } 290 if ((isrstatus & CDNS_UART_IXR_FRAMING) && 291 !framerrprocessed) { 292 port->icount.frame++; 293 status = TTY_FRAME; 294 } 295 } 296 if (isrstatus & CDNS_UART_IXR_OVERRUN) { 297 port->icount.overrun++; 298 tty_insert_flip_char(&port->state->port, 0, 299 TTY_OVERRUN); 300 } 301 tty_insert_flip_char(&port->state->port, data, status); 302 isrstatus = 0; 303 } 304 305 tty_flip_buffer_push(&port->state->port); 306 } 307 308 /** 309 * cdns_uart_handle_tx - Handle the bytes to be Txed. 310 * @dev_id: Id of the UART port 311 * Return: None 312 */ 313 static void cdns_uart_handle_tx(void *dev_id) 314 { 315 struct uart_port *port = (struct uart_port *)dev_id; 316 struct circ_buf *xmit = &port->state->xmit; 317 unsigned int numbytes; 318 319 if (uart_circ_empty(xmit)) { 320 writel(CDNS_UART_IXR_TXEMPTY, port->membase + CDNS_UART_IDR); 321 return; 322 } 323 324 numbytes = port->fifosize; 325 while (numbytes && !uart_circ_empty(xmit) && 326 !(readl(port->membase + CDNS_UART_SR) & CDNS_UART_SR_TXFULL)) { 327 328 writel(xmit->buf[xmit->tail], port->membase + CDNS_UART_FIFO); 329 uart_xmit_advance(port, 1); 330 numbytes--; 331 } 332 333 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) 334 uart_write_wakeup(port); 335 } 336 337 /** 338 * cdns_uart_isr - Interrupt handler 339 * @irq: Irq number 340 * @dev_id: Id of the port 341 * 342 * Return: IRQHANDLED 343 */ 344 static irqreturn_t cdns_uart_isr(int irq, void *dev_id) 345 { 346 struct uart_port *port = (struct uart_port *)dev_id; 347 unsigned int isrstatus; 348 349 spin_lock(&port->lock); 350 351 /* Read the interrupt status register to determine which 352 * interrupt(s) is/are active and clear them. 353 */ 354 isrstatus = readl(port->membase + CDNS_UART_ISR); 355 writel(isrstatus, port->membase + CDNS_UART_ISR); 356 357 if (isrstatus & CDNS_UART_IXR_TXEMPTY) { 358 cdns_uart_handle_tx(dev_id); 359 isrstatus &= ~CDNS_UART_IXR_TXEMPTY; 360 } 361 362 isrstatus &= port->read_status_mask; 363 isrstatus &= ~port->ignore_status_mask; 364 /* 365 * Skip RX processing if RX is disabled as RXEMPTY will never be set 366 * as read bytes will not be removed from the FIFO. 367 */ 368 if (isrstatus & CDNS_UART_IXR_RXMASK && 369 !(readl(port->membase + CDNS_UART_CR) & CDNS_UART_CR_RX_DIS)) 370 cdns_uart_handle_rx(dev_id, isrstatus); 371 372 spin_unlock(&port->lock); 373 return IRQ_HANDLED; 374 } 375 376 /** 377 * cdns_uart_calc_baud_divs - Calculate baud rate divisors 378 * @clk: UART module input clock 379 * @baud: Desired baud rate 380 * @rbdiv: BDIV value (return value) 381 * @rcd: CD value (return value) 382 * @div8: Value for clk_sel bit in mod (return value) 383 * Return: baud rate, requested baud when possible, or actual baud when there 384 * was too much error, zero if no valid divisors are found. 385 * 386 * Formula to obtain baud rate is 387 * baud_tx/rx rate = clk/CD * (BDIV + 1) 388 * input_clk = (Uart User Defined Clock or Apb Clock) 389 * depends on UCLKEN in MR Reg 390 * clk = input_clk or input_clk/8; 391 * depends on CLKS in MR reg 392 * CD and BDIV depends on values in 393 * baud rate generate register 394 * baud rate clock divisor register 395 */ 396 static unsigned int cdns_uart_calc_baud_divs(unsigned int clk, 397 unsigned int baud, u32 *rbdiv, u32 *rcd, int *div8) 398 { 399 u32 cd, bdiv; 400 unsigned int calc_baud; 401 unsigned int bestbaud = 0; 402 unsigned int bauderror; 403 unsigned int besterror = ~0; 404 405 if (baud < clk / ((CDNS_UART_BDIV_MAX + 1) * CDNS_UART_CD_MAX)) { 406 *div8 = 1; 407 clk /= 8; 408 } else { 409 *div8 = 0; 410 } 411 412 for (bdiv = CDNS_UART_BDIV_MIN; bdiv <= CDNS_UART_BDIV_MAX; bdiv++) { 413 cd = DIV_ROUND_CLOSEST(clk, baud * (bdiv + 1)); 414 if (cd < 1 || cd > CDNS_UART_CD_MAX) 415 continue; 416 417 calc_baud = clk / (cd * (bdiv + 1)); 418 419 if (baud > calc_baud) 420 bauderror = baud - calc_baud; 421 else 422 bauderror = calc_baud - baud; 423 424 if (besterror > bauderror) { 425 *rbdiv = bdiv; 426 *rcd = cd; 427 bestbaud = calc_baud; 428 besterror = bauderror; 429 } 430 } 431 /* use the values when percent error is acceptable */ 432 if (((besterror * 100) / baud) < 3) 433 bestbaud = baud; 434 435 return bestbaud; 436 } 437 438 /** 439 * cdns_uart_set_baud_rate - Calculate and set the baud rate 440 * @port: Handle to the uart port structure 441 * @baud: Baud rate to set 442 * Return: baud rate, requested baud when possible, or actual baud when there 443 * was too much error, zero if no valid divisors are found. 444 */ 445 static unsigned int cdns_uart_set_baud_rate(struct uart_port *port, 446 unsigned int baud) 447 { 448 unsigned int calc_baud; 449 u32 cd = 0, bdiv = 0; 450 u32 mreg; 451 int div8; 452 struct cdns_uart *cdns_uart = port->private_data; 453 454 calc_baud = cdns_uart_calc_baud_divs(port->uartclk, baud, &bdiv, &cd, 455 &div8); 456 457 /* Write new divisors to hardware */ 458 mreg = readl(port->membase + CDNS_UART_MR); 459 if (div8) 460 mreg |= CDNS_UART_MR_CLKSEL; 461 else 462 mreg &= ~CDNS_UART_MR_CLKSEL; 463 writel(mreg, port->membase + CDNS_UART_MR); 464 writel(cd, port->membase + CDNS_UART_BAUDGEN); 465 writel(bdiv, port->membase + CDNS_UART_BAUDDIV); 466 cdns_uart->baud = baud; 467 468 return calc_baud; 469 } 470 471 #ifdef CONFIG_COMMON_CLK 472 /** 473 * cdns_uart_clk_notifier_cb - Clock notifier callback 474 * @nb: Notifier block 475 * @event: Notify event 476 * @data: Notifier data 477 * Return: NOTIFY_OK or NOTIFY_DONE on success, NOTIFY_BAD on error. 478 */ 479 static int cdns_uart_clk_notifier_cb(struct notifier_block *nb, 480 unsigned long event, void *data) 481 { 482 u32 ctrl_reg; 483 struct uart_port *port; 484 int locked = 0; 485 struct clk_notifier_data *ndata = data; 486 struct cdns_uart *cdns_uart = to_cdns_uart(nb); 487 unsigned long flags; 488 489 port = cdns_uart->port; 490 if (port->suspended) 491 return NOTIFY_OK; 492 493 switch (event) { 494 case PRE_RATE_CHANGE: 495 { 496 u32 bdiv, cd; 497 int div8; 498 499 /* 500 * Find out if current baud-rate can be achieved with new clock 501 * frequency. 502 */ 503 if (!cdns_uart_calc_baud_divs(ndata->new_rate, cdns_uart->baud, 504 &bdiv, &cd, &div8)) { 505 dev_warn(port->dev, "clock rate change rejected\n"); 506 return NOTIFY_BAD; 507 } 508 509 spin_lock_irqsave(&cdns_uart->port->lock, flags); 510 511 /* Disable the TX and RX to set baud rate */ 512 ctrl_reg = readl(port->membase + CDNS_UART_CR); 513 ctrl_reg |= CDNS_UART_CR_TX_DIS | CDNS_UART_CR_RX_DIS; 514 writel(ctrl_reg, port->membase + CDNS_UART_CR); 515 516 spin_unlock_irqrestore(&cdns_uart->port->lock, flags); 517 518 return NOTIFY_OK; 519 } 520 case POST_RATE_CHANGE: 521 /* 522 * Set clk dividers to generate correct baud with new clock 523 * frequency. 524 */ 525 526 spin_lock_irqsave(&cdns_uart->port->lock, flags); 527 528 locked = 1; 529 port->uartclk = ndata->new_rate; 530 531 cdns_uart->baud = cdns_uart_set_baud_rate(cdns_uart->port, 532 cdns_uart->baud); 533 fallthrough; 534 case ABORT_RATE_CHANGE: 535 if (!locked) 536 spin_lock_irqsave(&cdns_uart->port->lock, flags); 537 538 /* Set TX/RX Reset */ 539 ctrl_reg = readl(port->membase + CDNS_UART_CR); 540 ctrl_reg |= CDNS_UART_CR_TXRST | CDNS_UART_CR_RXRST; 541 writel(ctrl_reg, port->membase + CDNS_UART_CR); 542 543 while (readl(port->membase + CDNS_UART_CR) & 544 (CDNS_UART_CR_TXRST | CDNS_UART_CR_RXRST)) 545 cpu_relax(); 546 547 /* 548 * Clear the RX disable and TX disable bits and then set the TX 549 * enable bit and RX enable bit to enable the transmitter and 550 * receiver. 551 */ 552 writel(rx_timeout, port->membase + CDNS_UART_RXTOUT); 553 ctrl_reg = readl(port->membase + CDNS_UART_CR); 554 ctrl_reg &= ~(CDNS_UART_CR_TX_DIS | CDNS_UART_CR_RX_DIS); 555 ctrl_reg |= CDNS_UART_CR_TX_EN | CDNS_UART_CR_RX_EN; 556 writel(ctrl_reg, port->membase + CDNS_UART_CR); 557 558 spin_unlock_irqrestore(&cdns_uart->port->lock, flags); 559 560 return NOTIFY_OK; 561 default: 562 return NOTIFY_DONE; 563 } 564 } 565 #endif 566 567 /** 568 * cdns_uart_start_tx - Start transmitting bytes 569 * @port: Handle to the uart port structure 570 */ 571 static void cdns_uart_start_tx(struct uart_port *port) 572 { 573 unsigned int status; 574 575 if (uart_tx_stopped(port)) 576 return; 577 578 /* 579 * Set the TX enable bit and clear the TX disable bit to enable the 580 * transmitter. 581 */ 582 status = readl(port->membase + CDNS_UART_CR); 583 status &= ~CDNS_UART_CR_TX_DIS; 584 status |= CDNS_UART_CR_TX_EN; 585 writel(status, port->membase + CDNS_UART_CR); 586 587 if (uart_circ_empty(&port->state->xmit)) 588 return; 589 590 writel(CDNS_UART_IXR_TXEMPTY, port->membase + CDNS_UART_ISR); 591 592 cdns_uart_handle_tx(port); 593 594 /* Enable the TX Empty interrupt */ 595 writel(CDNS_UART_IXR_TXEMPTY, port->membase + CDNS_UART_IER); 596 } 597 598 /** 599 * cdns_uart_stop_tx - Stop TX 600 * @port: Handle to the uart port structure 601 */ 602 static void cdns_uart_stop_tx(struct uart_port *port) 603 { 604 unsigned int regval; 605 606 regval = readl(port->membase + CDNS_UART_CR); 607 regval |= CDNS_UART_CR_TX_DIS; 608 /* Disable the transmitter */ 609 writel(regval, port->membase + CDNS_UART_CR); 610 } 611 612 /** 613 * cdns_uart_stop_rx - Stop RX 614 * @port: Handle to the uart port structure 615 */ 616 static void cdns_uart_stop_rx(struct uart_port *port) 617 { 618 unsigned int regval; 619 620 /* Disable RX IRQs */ 621 writel(CDNS_UART_RX_IRQS, port->membase + CDNS_UART_IDR); 622 623 /* Disable the receiver */ 624 regval = readl(port->membase + CDNS_UART_CR); 625 regval |= CDNS_UART_CR_RX_DIS; 626 writel(regval, port->membase + CDNS_UART_CR); 627 } 628 629 /** 630 * cdns_uart_tx_empty - Check whether TX is empty 631 * @port: Handle to the uart port structure 632 * 633 * Return: TIOCSER_TEMT on success, 0 otherwise 634 */ 635 static unsigned int cdns_uart_tx_empty(struct uart_port *port) 636 { 637 unsigned int status; 638 639 status = readl(port->membase + CDNS_UART_SR) & 640 (CDNS_UART_SR_TXEMPTY | CDNS_UART_SR_TACTIVE); 641 return (status == CDNS_UART_SR_TXEMPTY) ? TIOCSER_TEMT : 0; 642 } 643 644 /** 645 * cdns_uart_break_ctl - Based on the input ctl we have to start or stop 646 * transmitting char breaks 647 * @port: Handle to the uart port structure 648 * @ctl: Value based on which start or stop decision is taken 649 */ 650 static void cdns_uart_break_ctl(struct uart_port *port, int ctl) 651 { 652 unsigned int status; 653 unsigned long flags; 654 655 spin_lock_irqsave(&port->lock, flags); 656 657 status = readl(port->membase + CDNS_UART_CR); 658 659 if (ctl == -1) 660 writel(CDNS_UART_CR_STARTBRK | status, 661 port->membase + CDNS_UART_CR); 662 else { 663 if ((status & CDNS_UART_CR_STOPBRK) == 0) 664 writel(CDNS_UART_CR_STOPBRK | status, 665 port->membase + CDNS_UART_CR); 666 } 667 spin_unlock_irqrestore(&port->lock, flags); 668 } 669 670 /** 671 * cdns_uart_set_termios - termios operations, handling data length, parity, 672 * stop bits, flow control, baud rate 673 * @port: Handle to the uart port structure 674 * @termios: Handle to the input termios structure 675 * @old: Values of the previously saved termios structure 676 */ 677 static void cdns_uart_set_termios(struct uart_port *port, 678 struct ktermios *termios, 679 const struct ktermios *old) 680 { 681 u32 cval = 0; 682 unsigned int baud, minbaud, maxbaud; 683 unsigned long flags; 684 unsigned int ctrl_reg, mode_reg; 685 686 spin_lock_irqsave(&port->lock, flags); 687 688 /* Disable the TX and RX to set baud rate */ 689 ctrl_reg = readl(port->membase + CDNS_UART_CR); 690 ctrl_reg |= CDNS_UART_CR_TX_DIS | CDNS_UART_CR_RX_DIS; 691 writel(ctrl_reg, port->membase + CDNS_UART_CR); 692 693 /* 694 * Min baud rate = 6bps and Max Baud Rate is 10Mbps for 100Mhz clk 695 * min and max baud should be calculated here based on port->uartclk. 696 * this way we get a valid baud and can safely call set_baud() 697 */ 698 minbaud = port->uartclk / 699 ((CDNS_UART_BDIV_MAX + 1) * CDNS_UART_CD_MAX * 8); 700 maxbaud = port->uartclk / (CDNS_UART_BDIV_MIN + 1); 701 baud = uart_get_baud_rate(port, termios, old, minbaud, maxbaud); 702 baud = cdns_uart_set_baud_rate(port, baud); 703 if (tty_termios_baud_rate(termios)) 704 tty_termios_encode_baud_rate(termios, baud, baud); 705 706 /* Update the per-port timeout. */ 707 uart_update_timeout(port, termios->c_cflag, baud); 708 709 /* Set TX/RX Reset */ 710 ctrl_reg = readl(port->membase + CDNS_UART_CR); 711 ctrl_reg |= CDNS_UART_CR_TXRST | CDNS_UART_CR_RXRST; 712 writel(ctrl_reg, port->membase + CDNS_UART_CR); 713 714 while (readl(port->membase + CDNS_UART_CR) & 715 (CDNS_UART_CR_TXRST | CDNS_UART_CR_RXRST)) 716 cpu_relax(); 717 718 /* 719 * Clear the RX disable and TX disable bits and then set the TX enable 720 * bit and RX enable bit to enable the transmitter and receiver. 721 */ 722 ctrl_reg = readl(port->membase + CDNS_UART_CR); 723 ctrl_reg &= ~(CDNS_UART_CR_TX_DIS | CDNS_UART_CR_RX_DIS); 724 ctrl_reg |= CDNS_UART_CR_TX_EN | CDNS_UART_CR_RX_EN; 725 writel(ctrl_reg, port->membase + CDNS_UART_CR); 726 727 writel(rx_timeout, port->membase + CDNS_UART_RXTOUT); 728 729 port->read_status_mask = CDNS_UART_IXR_TXEMPTY | CDNS_UART_IXR_RXTRIG | 730 CDNS_UART_IXR_OVERRUN | CDNS_UART_IXR_TOUT; 731 port->ignore_status_mask = 0; 732 733 if (termios->c_iflag & INPCK) 734 port->read_status_mask |= CDNS_UART_IXR_PARITY | 735 CDNS_UART_IXR_FRAMING; 736 737 if (termios->c_iflag & IGNPAR) 738 port->ignore_status_mask |= CDNS_UART_IXR_PARITY | 739 CDNS_UART_IXR_FRAMING | CDNS_UART_IXR_OVERRUN; 740 741 /* ignore all characters if CREAD is not set */ 742 if ((termios->c_cflag & CREAD) == 0) 743 port->ignore_status_mask |= CDNS_UART_IXR_RXTRIG | 744 CDNS_UART_IXR_TOUT | CDNS_UART_IXR_PARITY | 745 CDNS_UART_IXR_FRAMING | CDNS_UART_IXR_OVERRUN; 746 747 mode_reg = readl(port->membase + CDNS_UART_MR); 748 749 /* Handling Data Size */ 750 switch (termios->c_cflag & CSIZE) { 751 case CS6: 752 cval |= CDNS_UART_MR_CHARLEN_6_BIT; 753 break; 754 case CS7: 755 cval |= CDNS_UART_MR_CHARLEN_7_BIT; 756 break; 757 default: 758 case CS8: 759 cval |= CDNS_UART_MR_CHARLEN_8_BIT; 760 termios->c_cflag &= ~CSIZE; 761 termios->c_cflag |= CS8; 762 break; 763 } 764 765 /* Handling Parity and Stop Bits length */ 766 if (termios->c_cflag & CSTOPB) 767 cval |= CDNS_UART_MR_STOPMODE_2_BIT; /* 2 STOP bits */ 768 else 769 cval |= CDNS_UART_MR_STOPMODE_1_BIT; /* 1 STOP bit */ 770 771 if (termios->c_cflag & PARENB) { 772 /* Mark or Space parity */ 773 if (termios->c_cflag & CMSPAR) { 774 if (termios->c_cflag & PARODD) 775 cval |= CDNS_UART_MR_PARITY_MARK; 776 else 777 cval |= CDNS_UART_MR_PARITY_SPACE; 778 } else { 779 if (termios->c_cflag & PARODD) 780 cval |= CDNS_UART_MR_PARITY_ODD; 781 else 782 cval |= CDNS_UART_MR_PARITY_EVEN; 783 } 784 } else { 785 cval |= CDNS_UART_MR_PARITY_NONE; 786 } 787 cval |= mode_reg & 1; 788 writel(cval, port->membase + CDNS_UART_MR); 789 790 cval = readl(port->membase + CDNS_UART_MODEMCR); 791 if (termios->c_cflag & CRTSCTS) 792 cval |= CDNS_UART_MODEMCR_FCM; 793 else 794 cval &= ~CDNS_UART_MODEMCR_FCM; 795 writel(cval, port->membase + CDNS_UART_MODEMCR); 796 797 spin_unlock_irqrestore(&port->lock, flags); 798 } 799 800 /** 801 * cdns_uart_startup - Called when an application opens a cdns_uart port 802 * @port: Handle to the uart port structure 803 * 804 * Return: 0 on success, negative errno otherwise 805 */ 806 static int cdns_uart_startup(struct uart_port *port) 807 { 808 struct cdns_uart *cdns_uart = port->private_data; 809 bool is_brk_support; 810 int ret; 811 unsigned long flags; 812 unsigned int status = 0; 813 814 is_brk_support = cdns_uart->quirks & CDNS_UART_RXBS_SUPPORT; 815 816 spin_lock_irqsave(&port->lock, flags); 817 818 /* Disable the TX and RX */ 819 writel(CDNS_UART_CR_TX_DIS | CDNS_UART_CR_RX_DIS, 820 port->membase + CDNS_UART_CR); 821 822 /* Set the Control Register with TX/RX Enable, TX/RX Reset, 823 * no break chars. 824 */ 825 writel(CDNS_UART_CR_TXRST | CDNS_UART_CR_RXRST, 826 port->membase + CDNS_UART_CR); 827 828 while (readl(port->membase + CDNS_UART_CR) & 829 (CDNS_UART_CR_TXRST | CDNS_UART_CR_RXRST)) 830 cpu_relax(); 831 832 /* 833 * Clear the RX disable bit and then set the RX enable bit to enable 834 * the receiver. 835 */ 836 status = readl(port->membase + CDNS_UART_CR); 837 status &= ~CDNS_UART_CR_RX_DIS; 838 status |= CDNS_UART_CR_RX_EN; 839 writel(status, port->membase + CDNS_UART_CR); 840 841 /* Set the Mode Register with normal mode,8 data bits,1 stop bit, 842 * no parity. 843 */ 844 writel(CDNS_UART_MR_CHMODE_NORM | CDNS_UART_MR_STOPMODE_1_BIT 845 | CDNS_UART_MR_PARITY_NONE | CDNS_UART_MR_CHARLEN_8_BIT, 846 port->membase + CDNS_UART_MR); 847 848 /* 849 * Set the RX FIFO Trigger level to use most of the FIFO, but it 850 * can be tuned with a module parameter 851 */ 852 writel(rx_trigger_level, port->membase + CDNS_UART_RXWM); 853 854 /* 855 * Receive Timeout register is enabled but it 856 * can be tuned with a module parameter 857 */ 858 writel(rx_timeout, port->membase + CDNS_UART_RXTOUT); 859 860 /* Clear out any pending interrupts before enabling them */ 861 writel(readl(port->membase + CDNS_UART_ISR), 862 port->membase + CDNS_UART_ISR); 863 864 spin_unlock_irqrestore(&port->lock, flags); 865 866 ret = request_irq(port->irq, cdns_uart_isr, 0, CDNS_UART_NAME, port); 867 if (ret) { 868 dev_err(port->dev, "request_irq '%d' failed with %d\n", 869 port->irq, ret); 870 return ret; 871 } 872 873 /* Set the Interrupt Registers with desired interrupts */ 874 if (is_brk_support) 875 writel(CDNS_UART_RX_IRQS | CDNS_UART_IXR_BRK, 876 port->membase + CDNS_UART_IER); 877 else 878 writel(CDNS_UART_RX_IRQS, port->membase + CDNS_UART_IER); 879 880 return 0; 881 } 882 883 /** 884 * cdns_uart_shutdown - Called when an application closes a cdns_uart port 885 * @port: Handle to the uart port structure 886 */ 887 static void cdns_uart_shutdown(struct uart_port *port) 888 { 889 int status; 890 unsigned long flags; 891 892 spin_lock_irqsave(&port->lock, flags); 893 894 /* Disable interrupts */ 895 status = readl(port->membase + CDNS_UART_IMR); 896 writel(status, port->membase + CDNS_UART_IDR); 897 writel(0xffffffff, port->membase + CDNS_UART_ISR); 898 899 /* Disable the TX and RX */ 900 writel(CDNS_UART_CR_TX_DIS | CDNS_UART_CR_RX_DIS, 901 port->membase + CDNS_UART_CR); 902 903 spin_unlock_irqrestore(&port->lock, flags); 904 905 free_irq(port->irq, port); 906 } 907 908 /** 909 * cdns_uart_type - Set UART type to cdns_uart port 910 * @port: Handle to the uart port structure 911 * 912 * Return: string on success, NULL otherwise 913 */ 914 static const char *cdns_uart_type(struct uart_port *port) 915 { 916 return port->type == PORT_XUARTPS ? CDNS_UART_NAME : NULL; 917 } 918 919 /** 920 * cdns_uart_verify_port - Verify the port params 921 * @port: Handle to the uart port structure 922 * @ser: Handle to the structure whose members are compared 923 * 924 * Return: 0 on success, negative errno otherwise. 925 */ 926 static int cdns_uart_verify_port(struct uart_port *port, 927 struct serial_struct *ser) 928 { 929 if (ser->type != PORT_UNKNOWN && ser->type != PORT_XUARTPS) 930 return -EINVAL; 931 if (port->irq != ser->irq) 932 return -EINVAL; 933 if (ser->io_type != UPIO_MEM) 934 return -EINVAL; 935 if (port->iobase != ser->port) 936 return -EINVAL; 937 if (ser->hub6 != 0) 938 return -EINVAL; 939 return 0; 940 } 941 942 /** 943 * cdns_uart_request_port - Claim the memory region attached to cdns_uart port, 944 * called when the driver adds a cdns_uart port via 945 * uart_add_one_port() 946 * @port: Handle to the uart port structure 947 * 948 * Return: 0 on success, negative errno otherwise. 949 */ 950 static int cdns_uart_request_port(struct uart_port *port) 951 { 952 if (!request_mem_region(port->mapbase, CDNS_UART_REGISTER_SPACE, 953 CDNS_UART_NAME)) { 954 return -ENOMEM; 955 } 956 957 port->membase = ioremap(port->mapbase, CDNS_UART_REGISTER_SPACE); 958 if (!port->membase) { 959 dev_err(port->dev, "Unable to map registers\n"); 960 release_mem_region(port->mapbase, CDNS_UART_REGISTER_SPACE); 961 return -ENOMEM; 962 } 963 return 0; 964 } 965 966 /** 967 * cdns_uart_release_port - Release UART port 968 * @port: Handle to the uart port structure 969 * 970 * Release the memory region attached to a cdns_uart port. Called when the 971 * driver removes a cdns_uart port via uart_remove_one_port(). 972 */ 973 static void cdns_uart_release_port(struct uart_port *port) 974 { 975 release_mem_region(port->mapbase, CDNS_UART_REGISTER_SPACE); 976 iounmap(port->membase); 977 port->membase = NULL; 978 } 979 980 /** 981 * cdns_uart_config_port - Configure UART port 982 * @port: Handle to the uart port structure 983 * @flags: If any 984 */ 985 static void cdns_uart_config_port(struct uart_port *port, int flags) 986 { 987 if (flags & UART_CONFIG_TYPE && cdns_uart_request_port(port) == 0) 988 port->type = PORT_XUARTPS; 989 } 990 991 /** 992 * cdns_uart_get_mctrl - Get the modem control state 993 * @port: Handle to the uart port structure 994 * 995 * Return: the modem control state 996 */ 997 static unsigned int cdns_uart_get_mctrl(struct uart_port *port) 998 { 999 u32 val; 1000 unsigned int mctrl = 0; 1001 struct cdns_uart *cdns_uart_data = port->private_data; 1002 1003 if (cdns_uart_data->cts_override) 1004 return TIOCM_CTS | TIOCM_DSR | TIOCM_CAR; 1005 1006 val = readl(port->membase + CDNS_UART_MODEMSR); 1007 if (val & CDNS_UART_MODEMSR_CTS) 1008 mctrl |= TIOCM_CTS; 1009 if (val & CDNS_UART_MODEMSR_DSR) 1010 mctrl |= TIOCM_DSR; 1011 if (val & CDNS_UART_MODEMSR_RI) 1012 mctrl |= TIOCM_RNG; 1013 if (val & CDNS_UART_MODEMSR_DCD) 1014 mctrl |= TIOCM_CAR; 1015 1016 return mctrl; 1017 } 1018 1019 static void cdns_uart_set_mctrl(struct uart_port *port, unsigned int mctrl) 1020 { 1021 u32 val; 1022 u32 mode_reg; 1023 struct cdns_uart *cdns_uart_data = port->private_data; 1024 1025 if (cdns_uart_data->cts_override) 1026 return; 1027 1028 val = readl(port->membase + CDNS_UART_MODEMCR); 1029 mode_reg = readl(port->membase + CDNS_UART_MR); 1030 1031 val &= ~(CDNS_UART_MODEMCR_RTS | CDNS_UART_MODEMCR_DTR); 1032 mode_reg &= ~CDNS_UART_MR_CHMODE_MASK; 1033 1034 if (mctrl & TIOCM_RTS) 1035 val |= CDNS_UART_MODEMCR_RTS; 1036 if (mctrl & TIOCM_DTR) 1037 val |= CDNS_UART_MODEMCR_DTR; 1038 if (mctrl & TIOCM_LOOP) 1039 mode_reg |= CDNS_UART_MR_CHMODE_L_LOOP; 1040 else 1041 mode_reg |= CDNS_UART_MR_CHMODE_NORM; 1042 1043 writel(val, port->membase + CDNS_UART_MODEMCR); 1044 writel(mode_reg, port->membase + CDNS_UART_MR); 1045 } 1046 1047 #ifdef CONFIG_CONSOLE_POLL 1048 static int cdns_uart_poll_get_char(struct uart_port *port) 1049 { 1050 int c; 1051 unsigned long flags; 1052 1053 spin_lock_irqsave(&port->lock, flags); 1054 1055 /* Check if FIFO is empty */ 1056 if (readl(port->membase + CDNS_UART_SR) & CDNS_UART_SR_RXEMPTY) 1057 c = NO_POLL_CHAR; 1058 else /* Read a character */ 1059 c = (unsigned char) readl(port->membase + CDNS_UART_FIFO); 1060 1061 spin_unlock_irqrestore(&port->lock, flags); 1062 1063 return c; 1064 } 1065 1066 static void cdns_uart_poll_put_char(struct uart_port *port, unsigned char c) 1067 { 1068 unsigned long flags; 1069 1070 spin_lock_irqsave(&port->lock, flags); 1071 1072 /* Wait until FIFO is empty */ 1073 while (!(readl(port->membase + CDNS_UART_SR) & CDNS_UART_SR_TXEMPTY)) 1074 cpu_relax(); 1075 1076 /* Write a character */ 1077 writel(c, port->membase + CDNS_UART_FIFO); 1078 1079 /* Wait until FIFO is empty */ 1080 while (!(readl(port->membase + CDNS_UART_SR) & CDNS_UART_SR_TXEMPTY)) 1081 cpu_relax(); 1082 1083 spin_unlock_irqrestore(&port->lock, flags); 1084 } 1085 #endif 1086 1087 static void cdns_uart_pm(struct uart_port *port, unsigned int state, 1088 unsigned int oldstate) 1089 { 1090 switch (state) { 1091 case UART_PM_STATE_OFF: 1092 pm_runtime_mark_last_busy(port->dev); 1093 pm_runtime_put_autosuspend(port->dev); 1094 break; 1095 default: 1096 pm_runtime_get_sync(port->dev); 1097 break; 1098 } 1099 } 1100 1101 static const struct uart_ops cdns_uart_ops = { 1102 .set_mctrl = cdns_uart_set_mctrl, 1103 .get_mctrl = cdns_uart_get_mctrl, 1104 .start_tx = cdns_uart_start_tx, 1105 .stop_tx = cdns_uart_stop_tx, 1106 .stop_rx = cdns_uart_stop_rx, 1107 .tx_empty = cdns_uart_tx_empty, 1108 .break_ctl = cdns_uart_break_ctl, 1109 .set_termios = cdns_uart_set_termios, 1110 .startup = cdns_uart_startup, 1111 .shutdown = cdns_uart_shutdown, 1112 .pm = cdns_uart_pm, 1113 .type = cdns_uart_type, 1114 .verify_port = cdns_uart_verify_port, 1115 .request_port = cdns_uart_request_port, 1116 .release_port = cdns_uart_release_port, 1117 .config_port = cdns_uart_config_port, 1118 #ifdef CONFIG_CONSOLE_POLL 1119 .poll_get_char = cdns_uart_poll_get_char, 1120 .poll_put_char = cdns_uart_poll_put_char, 1121 #endif 1122 }; 1123 1124 static struct uart_driver cdns_uart_uart_driver; 1125 1126 #ifdef CONFIG_SERIAL_XILINX_PS_UART_CONSOLE 1127 /** 1128 * cdns_uart_console_putchar - write the character to the FIFO buffer 1129 * @port: Handle to the uart port structure 1130 * @ch: Character to be written 1131 */ 1132 static void cdns_uart_console_putchar(struct uart_port *port, unsigned char ch) 1133 { 1134 unsigned int ctrl_reg; 1135 unsigned long timeout; 1136 1137 timeout = jiffies + msecs_to_jiffies(1000); 1138 while (1) { 1139 ctrl_reg = readl(port->membase + CDNS_UART_CR); 1140 if (!(ctrl_reg & CDNS_UART_CR_TX_DIS)) 1141 break; 1142 if (time_after(jiffies, timeout)) { 1143 dev_warn(port->dev, 1144 "timeout waiting for Enable\n"); 1145 return; 1146 } 1147 cpu_relax(); 1148 } 1149 1150 timeout = jiffies + msecs_to_jiffies(1000); 1151 while (1) { 1152 ctrl_reg = readl(port->membase + CDNS_UART_SR); 1153 1154 if (!(ctrl_reg & CDNS_UART_SR_TXFULL)) 1155 break; 1156 if (time_after(jiffies, timeout)) { 1157 dev_warn(port->dev, 1158 "timeout waiting for TX fifo\n"); 1159 return; 1160 } 1161 cpu_relax(); 1162 } 1163 writel(ch, port->membase + CDNS_UART_FIFO); 1164 } 1165 1166 static void cdns_early_write(struct console *con, const char *s, 1167 unsigned int n) 1168 { 1169 struct earlycon_device *dev = con->data; 1170 1171 uart_console_write(&dev->port, s, n, cdns_uart_console_putchar); 1172 } 1173 1174 static int __init cdns_early_console_setup(struct earlycon_device *device, 1175 const char *opt) 1176 { 1177 struct uart_port *port = &device->port; 1178 1179 if (!port->membase) 1180 return -ENODEV; 1181 1182 /* initialise control register */ 1183 writel(CDNS_UART_CR_TX_EN|CDNS_UART_CR_TXRST|CDNS_UART_CR_RXRST, 1184 port->membase + CDNS_UART_CR); 1185 1186 /* only set baud if specified on command line - otherwise 1187 * assume it has been initialized by a boot loader. 1188 */ 1189 if (port->uartclk && device->baud) { 1190 u32 cd = 0, bdiv = 0; 1191 u32 mr; 1192 int div8; 1193 1194 cdns_uart_calc_baud_divs(port->uartclk, device->baud, 1195 &bdiv, &cd, &div8); 1196 mr = CDNS_UART_MR_PARITY_NONE; 1197 if (div8) 1198 mr |= CDNS_UART_MR_CLKSEL; 1199 1200 writel(mr, port->membase + CDNS_UART_MR); 1201 writel(cd, port->membase + CDNS_UART_BAUDGEN); 1202 writel(bdiv, port->membase + CDNS_UART_BAUDDIV); 1203 } 1204 1205 device->con->write = cdns_early_write; 1206 1207 return 0; 1208 } 1209 OF_EARLYCON_DECLARE(cdns, "xlnx,xuartps", cdns_early_console_setup); 1210 OF_EARLYCON_DECLARE(cdns, "cdns,uart-r1p8", cdns_early_console_setup); 1211 OF_EARLYCON_DECLARE(cdns, "cdns,uart-r1p12", cdns_early_console_setup); 1212 OF_EARLYCON_DECLARE(cdns, "xlnx,zynqmp-uart", cdns_early_console_setup); 1213 1214 1215 /* Static pointer to console port */ 1216 static struct uart_port *console_port; 1217 1218 /** 1219 * cdns_uart_console_write - perform write operation 1220 * @co: Console handle 1221 * @s: Pointer to character array 1222 * @count: No of characters 1223 */ 1224 static void cdns_uart_console_write(struct console *co, const char *s, 1225 unsigned int count) 1226 { 1227 struct uart_port *port = console_port; 1228 unsigned long flags; 1229 unsigned int imr, ctrl; 1230 int locked = 1; 1231 1232 if (port->sysrq) 1233 locked = 0; 1234 else if (oops_in_progress) 1235 locked = spin_trylock_irqsave(&port->lock, flags); 1236 else 1237 spin_lock_irqsave(&port->lock, flags); 1238 1239 /* save and disable interrupt */ 1240 imr = readl(port->membase + CDNS_UART_IMR); 1241 writel(imr, port->membase + CDNS_UART_IDR); 1242 1243 /* 1244 * Make sure that the tx part is enabled. Set the TX enable bit and 1245 * clear the TX disable bit to enable the transmitter. 1246 */ 1247 ctrl = readl(port->membase + CDNS_UART_CR); 1248 ctrl &= ~CDNS_UART_CR_TX_DIS; 1249 ctrl |= CDNS_UART_CR_TX_EN; 1250 writel(ctrl, port->membase + CDNS_UART_CR); 1251 1252 uart_console_write(port, s, count, cdns_uart_console_putchar); 1253 while (cdns_uart_tx_empty(port) != TIOCSER_TEMT) 1254 cpu_relax(); 1255 1256 /* restore interrupt state */ 1257 writel(imr, port->membase + CDNS_UART_IER); 1258 1259 if (locked) 1260 spin_unlock_irqrestore(&port->lock, flags); 1261 } 1262 1263 /** 1264 * cdns_uart_console_setup - Initialize the uart to default config 1265 * @co: Console handle 1266 * @options: Initial settings of uart 1267 * 1268 * Return: 0 on success, negative errno otherwise. 1269 */ 1270 static int cdns_uart_console_setup(struct console *co, char *options) 1271 { 1272 struct uart_port *port = console_port; 1273 1274 int baud = 9600; 1275 int bits = 8; 1276 int parity = 'n'; 1277 int flow = 'n'; 1278 unsigned long time_out; 1279 1280 if (!port->membase) { 1281 pr_debug("console on " CDNS_UART_TTY_NAME "%i not present\n", 1282 co->index); 1283 return -ENODEV; 1284 } 1285 1286 if (options) 1287 uart_parse_options(options, &baud, &parity, &bits, &flow); 1288 1289 /* Wait for tx_empty before setting up the console */ 1290 time_out = jiffies + usecs_to_jiffies(TX_TIMEOUT); 1291 1292 while (time_before(jiffies, time_out) && 1293 cdns_uart_tx_empty(port) != TIOCSER_TEMT) 1294 cpu_relax(); 1295 1296 return uart_set_options(port, co, baud, parity, bits, flow); 1297 } 1298 1299 static struct console cdns_uart_console = { 1300 .name = CDNS_UART_TTY_NAME, 1301 .write = cdns_uart_console_write, 1302 .device = uart_console_device, 1303 .setup = cdns_uart_console_setup, 1304 .flags = CON_PRINTBUFFER, 1305 .index = -1, /* Specified on the cmdline (e.g. console=ttyPS ) */ 1306 .data = &cdns_uart_uart_driver, 1307 }; 1308 #endif /* CONFIG_SERIAL_XILINX_PS_UART_CONSOLE */ 1309 1310 #ifdef CONFIG_PM_SLEEP 1311 /** 1312 * cdns_uart_suspend - suspend event 1313 * @device: Pointer to the device structure 1314 * 1315 * Return: 0 1316 */ 1317 static int cdns_uart_suspend(struct device *device) 1318 { 1319 struct uart_port *port = dev_get_drvdata(device); 1320 struct cdns_uart *cdns_uart = port->private_data; 1321 int may_wake; 1322 1323 may_wake = device_may_wakeup(device); 1324 1325 if (console_suspend_enabled && uart_console(port) && may_wake) { 1326 unsigned long flags; 1327 1328 spin_lock_irqsave(&port->lock, flags); 1329 /* Empty the receive FIFO 1st before making changes */ 1330 while (!(readl(port->membase + CDNS_UART_SR) & 1331 CDNS_UART_SR_RXEMPTY)) 1332 readl(port->membase + CDNS_UART_FIFO); 1333 /* set RX trigger level to 1 */ 1334 writel(1, port->membase + CDNS_UART_RXWM); 1335 /* disable RX timeout interrups */ 1336 writel(CDNS_UART_IXR_TOUT, port->membase + CDNS_UART_IDR); 1337 spin_unlock_irqrestore(&port->lock, flags); 1338 } 1339 1340 /* 1341 * Call the API provided in serial_core.c file which handles 1342 * the suspend. 1343 */ 1344 return uart_suspend_port(cdns_uart->cdns_uart_driver, port); 1345 } 1346 1347 /** 1348 * cdns_uart_resume - Resume after a previous suspend 1349 * @device: Pointer to the device structure 1350 * 1351 * Return: 0 1352 */ 1353 static int cdns_uart_resume(struct device *device) 1354 { 1355 struct uart_port *port = dev_get_drvdata(device); 1356 struct cdns_uart *cdns_uart = port->private_data; 1357 unsigned long flags; 1358 u32 ctrl_reg; 1359 int may_wake; 1360 int ret; 1361 1362 may_wake = device_may_wakeup(device); 1363 1364 if (console_suspend_enabled && uart_console(port) && !may_wake) { 1365 ret = clk_enable(cdns_uart->pclk); 1366 if (ret) 1367 return ret; 1368 1369 ret = clk_enable(cdns_uart->uartclk); 1370 if (ret) { 1371 clk_disable(cdns_uart->pclk); 1372 return ret; 1373 } 1374 1375 spin_lock_irqsave(&port->lock, flags); 1376 1377 /* Set TX/RX Reset */ 1378 ctrl_reg = readl(port->membase + CDNS_UART_CR); 1379 ctrl_reg |= CDNS_UART_CR_TXRST | CDNS_UART_CR_RXRST; 1380 writel(ctrl_reg, port->membase + CDNS_UART_CR); 1381 while (readl(port->membase + CDNS_UART_CR) & 1382 (CDNS_UART_CR_TXRST | CDNS_UART_CR_RXRST)) 1383 cpu_relax(); 1384 1385 /* restore rx timeout value */ 1386 writel(rx_timeout, port->membase + CDNS_UART_RXTOUT); 1387 /* Enable Tx/Rx */ 1388 ctrl_reg = readl(port->membase + CDNS_UART_CR); 1389 ctrl_reg &= ~(CDNS_UART_CR_TX_DIS | CDNS_UART_CR_RX_DIS); 1390 ctrl_reg |= CDNS_UART_CR_TX_EN | CDNS_UART_CR_RX_EN; 1391 writel(ctrl_reg, port->membase + CDNS_UART_CR); 1392 1393 clk_disable(cdns_uart->uartclk); 1394 clk_disable(cdns_uart->pclk); 1395 spin_unlock_irqrestore(&port->lock, flags); 1396 } else { 1397 spin_lock_irqsave(&port->lock, flags); 1398 /* restore original rx trigger level */ 1399 writel(rx_trigger_level, port->membase + CDNS_UART_RXWM); 1400 /* enable RX timeout interrupt */ 1401 writel(CDNS_UART_IXR_TOUT, port->membase + CDNS_UART_IER); 1402 spin_unlock_irqrestore(&port->lock, flags); 1403 } 1404 1405 return uart_resume_port(cdns_uart->cdns_uart_driver, port); 1406 } 1407 #endif /* ! CONFIG_PM_SLEEP */ 1408 static int __maybe_unused cdns_runtime_suspend(struct device *dev) 1409 { 1410 struct uart_port *port = dev_get_drvdata(dev); 1411 struct cdns_uart *cdns_uart = port->private_data; 1412 1413 clk_disable(cdns_uart->uartclk); 1414 clk_disable(cdns_uart->pclk); 1415 return 0; 1416 }; 1417 1418 static int __maybe_unused cdns_runtime_resume(struct device *dev) 1419 { 1420 struct uart_port *port = dev_get_drvdata(dev); 1421 struct cdns_uart *cdns_uart = port->private_data; 1422 int ret; 1423 1424 ret = clk_enable(cdns_uart->pclk); 1425 if (ret) 1426 return ret; 1427 1428 ret = clk_enable(cdns_uart->uartclk); 1429 if (ret) { 1430 clk_disable(cdns_uart->pclk); 1431 return ret; 1432 } 1433 return 0; 1434 }; 1435 1436 static const struct dev_pm_ops cdns_uart_dev_pm_ops = { 1437 SET_SYSTEM_SLEEP_PM_OPS(cdns_uart_suspend, cdns_uart_resume) 1438 SET_RUNTIME_PM_OPS(cdns_runtime_suspend, 1439 cdns_runtime_resume, NULL) 1440 }; 1441 1442 static const struct cdns_platform_data zynqmp_uart_def = { 1443 .quirks = CDNS_UART_RXBS_SUPPORT, }; 1444 1445 /* Match table for of_platform binding */ 1446 static const struct of_device_id cdns_uart_of_match[] = { 1447 { .compatible = "xlnx,xuartps", }, 1448 { .compatible = "cdns,uart-r1p8", }, 1449 { .compatible = "cdns,uart-r1p12", .data = &zynqmp_uart_def }, 1450 { .compatible = "xlnx,zynqmp-uart", .data = &zynqmp_uart_def }, 1451 {} 1452 }; 1453 MODULE_DEVICE_TABLE(of, cdns_uart_of_match); 1454 1455 /* Temporary variable for storing number of instances */ 1456 static int instances; 1457 1458 /** 1459 * cdns_uart_probe - Platform driver probe 1460 * @pdev: Pointer to the platform device structure 1461 * 1462 * Return: 0 on success, negative errno otherwise 1463 */ 1464 static int cdns_uart_probe(struct platform_device *pdev) 1465 { 1466 int rc, id, irq; 1467 struct uart_port *port; 1468 struct resource *res; 1469 struct cdns_uart *cdns_uart_data; 1470 const struct of_device_id *match; 1471 1472 cdns_uart_data = devm_kzalloc(&pdev->dev, sizeof(*cdns_uart_data), 1473 GFP_KERNEL); 1474 if (!cdns_uart_data) 1475 return -ENOMEM; 1476 port = devm_kzalloc(&pdev->dev, sizeof(*port), GFP_KERNEL); 1477 if (!port) 1478 return -ENOMEM; 1479 1480 /* Look for a serialN alias */ 1481 id = of_alias_get_id(pdev->dev.of_node, "serial"); 1482 if (id < 0) 1483 id = 0; 1484 1485 if (id >= CDNS_UART_NR_PORTS) { 1486 dev_err(&pdev->dev, "Cannot get uart_port structure\n"); 1487 return -ENODEV; 1488 } 1489 1490 if (!cdns_uart_uart_driver.state) { 1491 cdns_uart_uart_driver.owner = THIS_MODULE; 1492 cdns_uart_uart_driver.driver_name = CDNS_UART_NAME; 1493 cdns_uart_uart_driver.dev_name = CDNS_UART_TTY_NAME; 1494 cdns_uart_uart_driver.major = CDNS_UART_MAJOR; 1495 cdns_uart_uart_driver.minor = CDNS_UART_MINOR; 1496 cdns_uart_uart_driver.nr = CDNS_UART_NR_PORTS; 1497 #ifdef CONFIG_SERIAL_XILINX_PS_UART_CONSOLE 1498 cdns_uart_uart_driver.cons = &cdns_uart_console; 1499 #endif 1500 1501 rc = uart_register_driver(&cdns_uart_uart_driver); 1502 if (rc < 0) { 1503 dev_err(&pdev->dev, "Failed to register driver\n"); 1504 return rc; 1505 } 1506 } 1507 1508 cdns_uart_data->cdns_uart_driver = &cdns_uart_uart_driver; 1509 1510 match = of_match_node(cdns_uart_of_match, pdev->dev.of_node); 1511 if (match && match->data) { 1512 const struct cdns_platform_data *data = match->data; 1513 1514 cdns_uart_data->quirks = data->quirks; 1515 } 1516 1517 cdns_uart_data->pclk = devm_clk_get(&pdev->dev, "pclk"); 1518 if (PTR_ERR(cdns_uart_data->pclk) == -EPROBE_DEFER) { 1519 rc = PTR_ERR(cdns_uart_data->pclk); 1520 goto err_out_unregister_driver; 1521 } 1522 1523 if (IS_ERR(cdns_uart_data->pclk)) { 1524 cdns_uart_data->pclk = devm_clk_get(&pdev->dev, "aper_clk"); 1525 if (IS_ERR(cdns_uart_data->pclk)) { 1526 rc = PTR_ERR(cdns_uart_data->pclk); 1527 goto err_out_unregister_driver; 1528 } 1529 dev_err(&pdev->dev, "clock name 'aper_clk' is deprecated.\n"); 1530 } 1531 1532 cdns_uart_data->uartclk = devm_clk_get(&pdev->dev, "uart_clk"); 1533 if (PTR_ERR(cdns_uart_data->uartclk) == -EPROBE_DEFER) { 1534 rc = PTR_ERR(cdns_uart_data->uartclk); 1535 goto err_out_unregister_driver; 1536 } 1537 1538 if (IS_ERR(cdns_uart_data->uartclk)) { 1539 cdns_uart_data->uartclk = devm_clk_get(&pdev->dev, "ref_clk"); 1540 if (IS_ERR(cdns_uart_data->uartclk)) { 1541 rc = PTR_ERR(cdns_uart_data->uartclk); 1542 goto err_out_unregister_driver; 1543 } 1544 dev_err(&pdev->dev, "clock name 'ref_clk' is deprecated.\n"); 1545 } 1546 1547 rc = clk_prepare_enable(cdns_uart_data->pclk); 1548 if (rc) { 1549 dev_err(&pdev->dev, "Unable to enable pclk clock.\n"); 1550 goto err_out_unregister_driver; 1551 } 1552 rc = clk_prepare_enable(cdns_uart_data->uartclk); 1553 if (rc) { 1554 dev_err(&pdev->dev, "Unable to enable device clock.\n"); 1555 goto err_out_clk_dis_pclk; 1556 } 1557 1558 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 1559 if (!res) { 1560 rc = -ENODEV; 1561 goto err_out_clk_disable; 1562 } 1563 1564 irq = platform_get_irq(pdev, 0); 1565 if (irq <= 0) { 1566 rc = -ENXIO; 1567 goto err_out_clk_disable; 1568 } 1569 1570 #ifdef CONFIG_COMMON_CLK 1571 cdns_uart_data->clk_rate_change_nb.notifier_call = 1572 cdns_uart_clk_notifier_cb; 1573 if (clk_notifier_register(cdns_uart_data->uartclk, 1574 &cdns_uart_data->clk_rate_change_nb)) 1575 dev_warn(&pdev->dev, "Unable to register clock notifier.\n"); 1576 #endif 1577 1578 /* At this point, we've got an empty uart_port struct, initialize it */ 1579 spin_lock_init(&port->lock); 1580 port->type = PORT_UNKNOWN; 1581 port->iotype = UPIO_MEM32; 1582 port->flags = UPF_BOOT_AUTOCONF; 1583 port->ops = &cdns_uart_ops; 1584 port->fifosize = CDNS_UART_FIFO_SIZE; 1585 port->has_sysrq = IS_ENABLED(CONFIG_SERIAL_XILINX_PS_UART_CONSOLE); 1586 port->line = id; 1587 1588 /* 1589 * Register the port. 1590 * This function also registers this device with the tty layer 1591 * and triggers invocation of the config_port() entry point. 1592 */ 1593 port->mapbase = res->start; 1594 port->irq = irq; 1595 port->dev = &pdev->dev; 1596 port->uartclk = clk_get_rate(cdns_uart_data->uartclk); 1597 port->private_data = cdns_uart_data; 1598 port->read_status_mask = CDNS_UART_IXR_TXEMPTY | CDNS_UART_IXR_RXTRIG | 1599 CDNS_UART_IXR_OVERRUN | CDNS_UART_IXR_TOUT; 1600 cdns_uart_data->port = port; 1601 platform_set_drvdata(pdev, port); 1602 1603 pm_runtime_use_autosuspend(&pdev->dev); 1604 pm_runtime_set_autosuspend_delay(&pdev->dev, UART_AUTOSUSPEND_TIMEOUT); 1605 pm_runtime_set_active(&pdev->dev); 1606 pm_runtime_enable(&pdev->dev); 1607 device_init_wakeup(port->dev, true); 1608 1609 #ifdef CONFIG_SERIAL_XILINX_PS_UART_CONSOLE 1610 /* 1611 * If console hasn't been found yet try to assign this port 1612 * because it is required to be assigned for console setup function. 1613 * If register_console() don't assign value, then console_port pointer 1614 * is cleanup. 1615 */ 1616 if (!console_port) { 1617 cdns_uart_console.index = id; 1618 console_port = port; 1619 } 1620 #endif 1621 1622 rc = uart_add_one_port(&cdns_uart_uart_driver, port); 1623 if (rc) { 1624 dev_err(&pdev->dev, 1625 "uart_add_one_port() failed; err=%i\n", rc); 1626 goto err_out_pm_disable; 1627 } 1628 1629 #ifdef CONFIG_SERIAL_XILINX_PS_UART_CONSOLE 1630 /* This is not port which is used for console that's why clean it up */ 1631 if (console_port == port && 1632 !console_is_registered(cdns_uart_uart_driver.cons)) { 1633 console_port = NULL; 1634 cdns_uart_console.index = -1; 1635 } 1636 #endif 1637 1638 cdns_uart_data->cts_override = of_property_read_bool(pdev->dev.of_node, 1639 "cts-override"); 1640 1641 instances++; 1642 1643 return 0; 1644 1645 err_out_pm_disable: 1646 pm_runtime_disable(&pdev->dev); 1647 pm_runtime_set_suspended(&pdev->dev); 1648 pm_runtime_dont_use_autosuspend(&pdev->dev); 1649 #ifdef CONFIG_COMMON_CLK 1650 clk_notifier_unregister(cdns_uart_data->uartclk, 1651 &cdns_uart_data->clk_rate_change_nb); 1652 #endif 1653 err_out_clk_disable: 1654 clk_disable_unprepare(cdns_uart_data->uartclk); 1655 err_out_clk_dis_pclk: 1656 clk_disable_unprepare(cdns_uart_data->pclk); 1657 err_out_unregister_driver: 1658 if (!instances) 1659 uart_unregister_driver(cdns_uart_data->cdns_uart_driver); 1660 return rc; 1661 } 1662 1663 /** 1664 * cdns_uart_remove - called when the platform driver is unregistered 1665 * @pdev: Pointer to the platform device structure 1666 * 1667 * Return: 0 on success, negative errno otherwise 1668 */ 1669 static int cdns_uart_remove(struct platform_device *pdev) 1670 { 1671 struct uart_port *port = platform_get_drvdata(pdev); 1672 struct cdns_uart *cdns_uart_data = port->private_data; 1673 int rc; 1674 1675 /* Remove the cdns_uart port from the serial core */ 1676 #ifdef CONFIG_COMMON_CLK 1677 clk_notifier_unregister(cdns_uart_data->uartclk, 1678 &cdns_uart_data->clk_rate_change_nb); 1679 #endif 1680 rc = uart_remove_one_port(cdns_uart_data->cdns_uart_driver, port); 1681 port->mapbase = 0; 1682 clk_disable_unprepare(cdns_uart_data->uartclk); 1683 clk_disable_unprepare(cdns_uart_data->pclk); 1684 pm_runtime_disable(&pdev->dev); 1685 pm_runtime_set_suspended(&pdev->dev); 1686 pm_runtime_dont_use_autosuspend(&pdev->dev); 1687 device_init_wakeup(&pdev->dev, false); 1688 1689 #ifdef CONFIG_SERIAL_XILINX_PS_UART_CONSOLE 1690 if (console_port == port) 1691 console_port = NULL; 1692 #endif 1693 1694 if (!--instances) 1695 uart_unregister_driver(cdns_uart_data->cdns_uart_driver); 1696 return rc; 1697 } 1698 1699 static struct platform_driver cdns_uart_platform_driver = { 1700 .probe = cdns_uart_probe, 1701 .remove = cdns_uart_remove, 1702 .driver = { 1703 .name = CDNS_UART_NAME, 1704 .of_match_table = cdns_uart_of_match, 1705 .pm = &cdns_uart_dev_pm_ops, 1706 .suppress_bind_attrs = IS_BUILTIN(CONFIG_SERIAL_XILINX_PS_UART), 1707 }, 1708 }; 1709 1710 static int __init cdns_uart_init(void) 1711 { 1712 /* Register the platform driver */ 1713 return platform_driver_register(&cdns_uart_platform_driver); 1714 } 1715 1716 static void __exit cdns_uart_exit(void) 1717 { 1718 /* Unregister the platform driver */ 1719 platform_driver_unregister(&cdns_uart_platform_driver); 1720 } 1721 1722 arch_initcall(cdns_uart_init); 1723 module_exit(cdns_uart_exit); 1724 1725 MODULE_DESCRIPTION("Driver for Cadence UART"); 1726 MODULE_AUTHOR("Xilinx Inc."); 1727 MODULE_LICENSE("GPL"); 1728