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/gpio.h>
26 #include <linux/gpio/consumer.h>
27 #include <linux/delay.h>
28 #include <linux/reset.h>
29
30 #define CDNS_UART_TTY_NAME "ttyPS"
31 #define CDNS_UART_NAME "xuartps"
32 #define CDNS_UART_MAJOR 0 /* use dynamic node allocation */
33 #define CDNS_UART_MINOR 0 /* works best with devtmpfs */
34 #define CDNS_UART_NR_PORTS 16
35 #define CDNS_UART_FIFO_SIZE 64 /* FIFO size */
36 #define CDNS_UART_REGISTER_SPACE 0x1000
37 #define TX_TIMEOUT 500000
38
39 /* Rx Trigger level */
40 static int rx_trigger_level = 56;
41 module_param(rx_trigger_level, uint, 0444);
42 MODULE_PARM_DESC(rx_trigger_level, "Rx trigger level, 1-63 bytes");
43
44 /* Rx Timeout */
45 static int rx_timeout = 10;
46 module_param(rx_timeout, uint, 0444);
47 MODULE_PARM_DESC(rx_timeout, "Rx timeout, 1-255");
48
49 /* Register offsets for the UART. */
50 #define CDNS_UART_CR 0x00 /* Control Register */
51 #define CDNS_UART_MR 0x04 /* Mode Register */
52 #define CDNS_UART_IER 0x08 /* Interrupt Enable */
53 #define CDNS_UART_IDR 0x0C /* Interrupt Disable */
54 #define CDNS_UART_IMR 0x10 /* Interrupt Mask */
55 #define CDNS_UART_ISR 0x14 /* Interrupt Status */
56 #define CDNS_UART_BAUDGEN 0x18 /* Baud Rate Generator */
57 #define CDNS_UART_RXTOUT 0x1C /* RX Timeout */
58 #define CDNS_UART_RXWM 0x20 /* RX FIFO Trigger Level */
59 #define CDNS_UART_MODEMCR 0x24 /* Modem Control */
60 #define CDNS_UART_MODEMSR 0x28 /* Modem Status */
61 #define CDNS_UART_SR 0x2C /* Channel Status */
62 #define CDNS_UART_FIFO 0x30 /* FIFO */
63 #define CDNS_UART_BAUDDIV 0x34 /* Baud Rate Divider */
64 #define CDNS_UART_FLOWDEL 0x38 /* Flow Delay */
65 #define CDNS_UART_IRRX_PWIDTH 0x3C /* IR Min Received Pulse Width */
66 #define CDNS_UART_IRTX_PWIDTH 0x40 /* IR Transmitted pulse Width */
67 #define CDNS_UART_TXWM 0x44 /* TX FIFO Trigger Level */
68 #define CDNS_UART_RXBS 0x48 /* RX FIFO byte status register */
69
70 /* Control Register Bit Definitions */
71 #define CDNS_UART_CR_STOPBRK 0x00000100 /* Stop TX break */
72 #define CDNS_UART_CR_STARTBRK 0x00000080 /* Set TX break */
73 #define CDNS_UART_CR_TX_DIS 0x00000020 /* TX disabled. */
74 #define CDNS_UART_CR_TX_EN 0x00000010 /* TX enabled */
75 #define CDNS_UART_CR_RX_DIS 0x00000008 /* RX disabled. */
76 #define CDNS_UART_CR_RX_EN 0x00000004 /* RX enabled */
77 #define CDNS_UART_CR_TXRST 0x00000002 /* TX logic reset */
78 #define CDNS_UART_CR_RXRST 0x00000001 /* RX logic reset */
79 #define CDNS_UART_CR_RST_TO 0x00000040 /* Restart Timeout Counter */
80 #define CDNS_UART_RXBS_PARITY 0x00000001 /* Parity error status */
81 #define CDNS_UART_RXBS_FRAMING 0x00000002 /* Framing error status */
82 #define CDNS_UART_RXBS_BRK 0x00000004 /* Overrun error status */
83
84 /*
85 * Mode Register:
86 * The mode register (MR) defines the mode of transfer as well as the data
87 * format. If this register is modified during transmission or reception,
88 * data validity cannot be guaranteed.
89 */
90 #define CDNS_UART_MR_CLKSEL 0x00000001 /* Pre-scalar selection */
91 #define CDNS_UART_MR_CHMODE_L_LOOP 0x00000200 /* Local loop back mode */
92 #define CDNS_UART_MR_CHMODE_NORM 0x00000000 /* Normal mode */
93 #define CDNS_UART_MR_CHMODE_MASK 0x00000300 /* Mask for mode bits */
94
95 #define CDNS_UART_MR_STOPMODE_2_BIT 0x00000080 /* 2 stop bits */
96 #define CDNS_UART_MR_STOPMODE_1_BIT 0x00000000 /* 1 stop bit */
97
98 #define CDNS_UART_MR_PARITY_NONE 0x00000020 /* No parity mode */
99 #define CDNS_UART_MR_PARITY_MARK 0x00000018 /* Mark parity mode */
100 #define CDNS_UART_MR_PARITY_SPACE 0x00000010 /* Space parity mode */
101 #define CDNS_UART_MR_PARITY_ODD 0x00000008 /* Odd parity mode */
102 #define CDNS_UART_MR_PARITY_EVEN 0x00000000 /* Even parity mode */
103
104 #define CDNS_UART_MR_CHARLEN_6_BIT 0x00000006 /* 6 bits data */
105 #define CDNS_UART_MR_CHARLEN_7_BIT 0x00000004 /* 7 bits data */
106 #define CDNS_UART_MR_CHARLEN_8_BIT 0x00000000 /* 8 bits data */
107
108 /*
109 * Interrupt Registers:
110 * Interrupt control logic uses the interrupt enable register (IER) and the
111 * interrupt disable register (IDR) to set the value of the bits in the
112 * interrupt mask register (IMR). The IMR determines whether to pass an
113 * interrupt to the interrupt status register (ISR).
114 * Writing a 1 to IER Enables an interrupt, writing a 1 to IDR disables an
115 * interrupt. IMR and ISR are read only, and IER and IDR are write only.
116 * Reading either IER or IDR returns 0x00.
117 * All four registers have the same bit definitions.
118 */
119 #define CDNS_UART_IXR_TOUT 0x00000100 /* RX Timeout error interrupt */
120 #define CDNS_UART_IXR_PARITY 0x00000080 /* Parity error interrupt */
121 #define CDNS_UART_IXR_FRAMING 0x00000040 /* Framing error interrupt */
122 #define CDNS_UART_IXR_OVERRUN 0x00000020 /* Overrun error interrupt */
123 #define CDNS_UART_IXR_TXFULL 0x00000010 /* TX FIFO Full interrupt */
124 #define CDNS_UART_IXR_TXEMPTY 0x00000008 /* TX FIFO empty interrupt */
125 #define CDNS_UART_ISR_RXEMPTY 0x00000002 /* RX FIFO empty interrupt */
126 #define CDNS_UART_IXR_RXTRIG 0x00000001 /* RX FIFO trigger interrupt */
127 #define CDNS_UART_IXR_RXFULL 0x00000004 /* RX FIFO full interrupt. */
128 #define CDNS_UART_IXR_RXEMPTY 0x00000002 /* RX FIFO empty interrupt. */
129 #define CDNS_UART_IXR_RXMASK 0x000021e7 /* Valid RX bit mask */
130
131 /*
132 * Do not enable parity error interrupt for the following
133 * reason: When parity error interrupt is enabled, each Rx
134 * parity error always results in 2 events. The first one
135 * being parity error interrupt and the second one with a
136 * proper Rx interrupt with the incoming data. Disabling
137 * parity error interrupt ensures better handling of parity
138 * error events. With this change, for a parity error case, we
139 * get a Rx interrupt with parity error set in ISR register
140 * and we still handle parity errors in the desired way.
141 */
142
143 #define CDNS_UART_RX_IRQS (CDNS_UART_IXR_FRAMING | \
144 CDNS_UART_IXR_OVERRUN | \
145 CDNS_UART_IXR_RXTRIG | \
146 CDNS_UART_IXR_TOUT)
147
148 /* Goes in read_status_mask for break detection as the HW doesn't do it*/
149 #define CDNS_UART_IXR_BRK 0x00002000
150
151 #define CDNS_UART_RXBS_SUPPORT BIT(1)
152 /*
153 * Modem Control register:
154 * The read/write Modem Control register controls the interface with the modem
155 * or data set, or a peripheral device emulating a modem.
156 */
157 #define CDNS_UART_MODEMCR_FCM 0x00000020 /* Automatic flow control mode */
158 #define CDNS_UART_MODEMCR_RTS 0x00000002 /* Request to send output control */
159 #define CDNS_UART_MODEMCR_DTR 0x00000001 /* Data Terminal Ready */
160
161 /*
162 * Modem Status register:
163 * The read/write Modem Status register reports the interface with the modem
164 * or data set, or a peripheral device emulating a modem.
165 */
166 #define CDNS_UART_MODEMSR_DCD BIT(7) /* Data Carrier Detect */
167 #define CDNS_UART_MODEMSR_RI BIT(6) /* Ting Indicator */
168 #define CDNS_UART_MODEMSR_DSR BIT(5) /* Data Set Ready */
169 #define CDNS_UART_MODEMSR_CTS BIT(4) /* Clear To Send */
170
171 /*
172 * Channel Status Register:
173 * The channel status register (CSR) is provided to enable the control logic
174 * to monitor the status of bits in the channel interrupt status register,
175 * even if these are masked out by the interrupt mask register.
176 */
177 #define CDNS_UART_SR_RXEMPTY 0x00000002 /* RX FIFO empty */
178 #define CDNS_UART_SR_TXEMPTY 0x00000008 /* TX FIFO empty */
179 #define CDNS_UART_SR_TXFULL 0x00000010 /* TX FIFO full */
180 #define CDNS_UART_SR_RXTRIG 0x00000001 /* Rx Trigger */
181 #define CDNS_UART_SR_TACTIVE 0x00000800 /* TX state machine active */
182
183 /* baud dividers min/max values */
184 #define CDNS_UART_BDIV_MIN 4
185 #define CDNS_UART_BDIV_MAX 255
186 #define CDNS_UART_CD_MAX 65535
187 #define UART_AUTOSUSPEND_TIMEOUT 3000
188
189 /**
190 * struct cdns_uart - device data
191 * @port: Pointer to the UART port
192 * @uartclk: Reference clock
193 * @pclk: APB clock
194 * @cdns_uart_driver: Pointer to UART driver
195 * @baud: Current baud rate
196 * @clk_rate_change_nb: Notifier block for clock changes
197 * @quirks: Flags for RXBS support.
198 * @cts_override: Modem control state override
199 * @gpiod_rts: Pointer to the gpio descriptor
200 * @rs485_tx_started: RS485 tx state
201 * @tx_timer: Timer for tx
202 * @rstc: Pointer to the reset control
203 */
204 struct cdns_uart {
205 struct uart_port *port;
206 struct clk *uartclk;
207 struct clk *pclk;
208 struct uart_driver *cdns_uart_driver;
209 unsigned int baud;
210 struct notifier_block clk_rate_change_nb;
211 u32 quirks;
212 bool cts_override;
213 struct gpio_desc *gpiod_rts;
214 bool rs485_tx_started;
215 struct hrtimer tx_timer;
216 struct reset_control *rstc;
217 };
218 struct cdns_platform_data {
219 u32 quirks;
220 };
221
222 static struct serial_rs485 cdns_rs485_supported = {
223 .flags = SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND |
224 SER_RS485_RTS_AFTER_SEND,
225 .delay_rts_before_send = 1,
226 .delay_rts_after_send = 1,
227 };
228
229 #define to_cdns_uart(_nb) container_of(_nb, struct cdns_uart, \
230 clk_rate_change_nb)
231
232 /**
233 * cdns_uart_handle_rx - Handle the received bytes along with Rx errors.
234 * @dev_id: Id of the UART port
235 * @isrstatus: The interrupt status register value as read
236 * Return: None
237 */
cdns_uart_handle_rx(void * dev_id,unsigned int isrstatus)238 static void cdns_uart_handle_rx(void *dev_id, unsigned int isrstatus)
239 {
240 struct uart_port *port = (struct uart_port *)dev_id;
241 struct cdns_uart *cdns_uart = port->private_data;
242 unsigned int data;
243 unsigned int rxbs_status = 0;
244 unsigned int status_mask;
245 unsigned int framerrprocessed = 0;
246 char status = TTY_NORMAL;
247 bool is_rxbs_support;
248
249 is_rxbs_support = cdns_uart->quirks & CDNS_UART_RXBS_SUPPORT;
250
251 while ((readl(port->membase + CDNS_UART_SR) &
252 CDNS_UART_SR_RXEMPTY) != CDNS_UART_SR_RXEMPTY) {
253 if (is_rxbs_support)
254 rxbs_status = readl(port->membase + CDNS_UART_RXBS);
255 data = readl(port->membase + CDNS_UART_FIFO);
256 port->icount.rx++;
257 /*
258 * There is no hardware break detection in Zynq, so we interpret
259 * framing error with all-zeros data as a break sequence.
260 * Most of the time, there's another non-zero byte at the
261 * end of the sequence.
262 */
263 if (!is_rxbs_support && (isrstatus & CDNS_UART_IXR_FRAMING)) {
264 if (!data) {
265 port->read_status_mask |= CDNS_UART_IXR_BRK;
266 framerrprocessed = 1;
267 continue;
268 }
269 }
270 if (is_rxbs_support && (rxbs_status & CDNS_UART_RXBS_BRK)) {
271 port->icount.brk++;
272 status = TTY_BREAK;
273 if (uart_handle_break(port))
274 continue;
275 }
276
277 isrstatus &= port->read_status_mask;
278 isrstatus &= ~port->ignore_status_mask;
279 status_mask = port->read_status_mask;
280 status_mask &= ~port->ignore_status_mask;
281
282 if (data &&
283 (port->read_status_mask & CDNS_UART_IXR_BRK)) {
284 port->read_status_mask &= ~CDNS_UART_IXR_BRK;
285 port->icount.brk++;
286 if (uart_handle_break(port))
287 continue;
288 }
289
290 if (uart_handle_sysrq_char(port, data))
291 continue;
292
293 if (is_rxbs_support) {
294 if ((rxbs_status & CDNS_UART_RXBS_PARITY)
295 && (status_mask & CDNS_UART_IXR_PARITY)) {
296 port->icount.parity++;
297 status = TTY_PARITY;
298 }
299 if ((rxbs_status & CDNS_UART_RXBS_FRAMING)
300 && (status_mask & CDNS_UART_IXR_PARITY)) {
301 port->icount.frame++;
302 status = TTY_FRAME;
303 }
304 } else {
305 if (isrstatus & CDNS_UART_IXR_PARITY) {
306 port->icount.parity++;
307 status = TTY_PARITY;
308 }
309 if ((isrstatus & CDNS_UART_IXR_FRAMING) &&
310 !framerrprocessed) {
311 port->icount.frame++;
312 status = TTY_FRAME;
313 }
314 }
315 if (isrstatus & CDNS_UART_IXR_OVERRUN) {
316 port->icount.overrun++;
317 tty_insert_flip_char(&port->state->port, 0,
318 TTY_OVERRUN);
319 }
320 tty_insert_flip_char(&port->state->port, data, status);
321 isrstatus = 0;
322 }
323
324 tty_flip_buffer_push(&port->state->port);
325 }
326
327 /**
328 * cdns_rts_gpio_enable - Configure RTS/GPIO to high/low
329 * @cdns_uart: Handle to the cdns_uart
330 * @enable: Value to be set to RTS/GPIO
331 */
cdns_rts_gpio_enable(struct cdns_uart * cdns_uart,bool enable)332 static void cdns_rts_gpio_enable(struct cdns_uart *cdns_uart, bool enable)
333 {
334 u32 val;
335
336 if (cdns_uart->gpiod_rts) {
337 gpiod_set_value(cdns_uart->gpiod_rts, enable);
338 } else {
339 val = readl(cdns_uart->port->membase + CDNS_UART_MODEMCR);
340 if (enable)
341 val |= CDNS_UART_MODEMCR_RTS;
342 else
343 val &= ~CDNS_UART_MODEMCR_RTS;
344 writel(val, cdns_uart->port->membase + CDNS_UART_MODEMCR);
345 }
346 }
347
348 /**
349 * cdns_rs485_tx_setup - Tx setup specific to rs485
350 * @cdns_uart: Handle to the cdns_uart
351 */
cdns_rs485_tx_setup(struct cdns_uart * cdns_uart)352 static void cdns_rs485_tx_setup(struct cdns_uart *cdns_uart)
353 {
354 bool enable;
355
356 enable = cdns_uart->port->rs485.flags & SER_RS485_RTS_ON_SEND;
357 cdns_rts_gpio_enable(cdns_uart, enable);
358
359 cdns_uart->rs485_tx_started = true;
360 }
361
362 /**
363 * cdns_rs485_rx_setup - Rx setup specific to rs485
364 * @cdns_uart: Handle to the cdns_uart
365 */
cdns_rs485_rx_setup(struct cdns_uart * cdns_uart)366 static void cdns_rs485_rx_setup(struct cdns_uart *cdns_uart)
367 {
368 bool enable;
369
370 enable = cdns_uart->port->rs485.flags & SER_RS485_RTS_AFTER_SEND;
371 cdns_rts_gpio_enable(cdns_uart, enable);
372
373 cdns_uart->rs485_tx_started = false;
374 }
375
376 /**
377 * cdns_uart_tx_empty - Check whether TX is empty
378 * @port: Handle to the uart port structure
379 *
380 * Return: TIOCSER_TEMT on success, 0 otherwise
381 */
cdns_uart_tx_empty(struct uart_port * port)382 static unsigned int cdns_uart_tx_empty(struct uart_port *port)
383 {
384 unsigned int status;
385
386 status = readl(port->membase + CDNS_UART_SR);
387 status &= (CDNS_UART_SR_TXEMPTY | CDNS_UART_SR_TACTIVE);
388 return (status == CDNS_UART_SR_TXEMPTY) ? TIOCSER_TEMT : 0;
389 }
390
391 /**
392 * cdns_rs485_rx_callback - Timer rx callback handler for rs485.
393 * @t: Handle to the hrtimer structure
394 */
cdns_rs485_rx_callback(struct hrtimer * t)395 static enum hrtimer_restart cdns_rs485_rx_callback(struct hrtimer *t)
396 {
397 struct cdns_uart *cdns_uart = container_of(t, struct cdns_uart, tx_timer);
398
399 /*
400 * Default Rx should be setup, because Rx signaling path
401 * need to enable to receive data.
402 */
403 cdns_rs485_rx_setup(cdns_uart);
404
405 return HRTIMER_NORESTART;
406 }
407
408 /**
409 * cdns_calc_after_tx_delay - calculate delay required for after tx.
410 * @cdns_uart: Handle to the cdns_uart
411 */
cdns_calc_after_tx_delay(struct cdns_uart * cdns_uart)412 static u64 cdns_calc_after_tx_delay(struct cdns_uart *cdns_uart)
413 {
414 /*
415 * Frame time + stop bit time + rs485.delay_rts_after_send
416 */
417 return cdns_uart->port->frame_time
418 + DIV_ROUND_UP(cdns_uart->port->frame_time, 7)
419 + (u64)cdns_uart->port->rs485.delay_rts_after_send * NSEC_PER_MSEC;
420 }
421
422 /**
423 * cdns_uart_handle_tx - Handle the bytes to be transmitted.
424 * @dev_id: Id of the UART port
425 * Return: None
426 */
cdns_uart_handle_tx(void * dev_id)427 static void cdns_uart_handle_tx(void *dev_id)
428 {
429 struct uart_port *port = (struct uart_port *)dev_id;
430 struct cdns_uart *cdns_uart = port->private_data;
431 struct tty_port *tport = &port->state->port;
432 unsigned int numbytes;
433 unsigned char ch;
434
435 if (kfifo_is_empty(&tport->xmit_fifo) || uart_tx_stopped(port)) {
436 /* Disable the TX Empty interrupt */
437 writel(CDNS_UART_IXR_TXEMPTY, port->membase + CDNS_UART_IDR);
438 return;
439 }
440
441 numbytes = port->fifosize;
442 while (numbytes &&
443 !(readl(port->membase + CDNS_UART_SR) & CDNS_UART_SR_TXFULL) &&
444 uart_fifo_get(port, &ch)) {
445 writel(ch, port->membase + CDNS_UART_FIFO);
446 numbytes--;
447 }
448
449 if (kfifo_len(&tport->xmit_fifo) < WAKEUP_CHARS)
450 uart_write_wakeup(port);
451
452 /* Enable the TX Empty interrupt */
453 writel(CDNS_UART_IXR_TXEMPTY, cdns_uart->port->membase + CDNS_UART_IER);
454
455 if (cdns_uart->port->rs485.flags & SER_RS485_ENABLED &&
456 (kfifo_is_empty(&tport->xmit_fifo) || uart_tx_stopped(port))) {
457 cdns_uart->tx_timer.function = &cdns_rs485_rx_callback;
458 hrtimer_start(&cdns_uart->tx_timer,
459 ns_to_ktime(cdns_calc_after_tx_delay(cdns_uart)), HRTIMER_MODE_REL);
460 }
461 }
462
463 /**
464 * cdns_uart_isr - Interrupt handler
465 * @irq: Irq number
466 * @dev_id: Id of the port
467 *
468 * Return: IRQHANDLED
469 */
cdns_uart_isr(int irq,void * dev_id)470 static irqreturn_t cdns_uart_isr(int irq, void *dev_id)
471 {
472 struct uart_port *port = (struct uart_port *)dev_id;
473 unsigned int isrstatus;
474
475 uart_port_lock(port);
476
477 /* Read the interrupt status register to determine which
478 * interrupt(s) is/are active and clear them.
479 */
480 isrstatus = readl(port->membase + CDNS_UART_ISR);
481 writel(isrstatus, port->membase + CDNS_UART_ISR);
482
483 if (isrstatus & CDNS_UART_IXR_TXEMPTY) {
484 cdns_uart_handle_tx(dev_id);
485 isrstatus &= ~CDNS_UART_IXR_TXEMPTY;
486 }
487
488 isrstatus &= port->read_status_mask;
489 isrstatus &= ~port->ignore_status_mask;
490 /*
491 * Skip RX processing if RX is disabled as RXEMPTY will never be set
492 * as read bytes will not be removed from the FIFO.
493 */
494 if (isrstatus & CDNS_UART_IXR_RXMASK &&
495 !(readl(port->membase + CDNS_UART_CR) & CDNS_UART_CR_RX_DIS))
496 cdns_uart_handle_rx(dev_id, isrstatus);
497
498 uart_port_unlock(port);
499 return IRQ_HANDLED;
500 }
501
502 /**
503 * cdns_uart_calc_baud_divs - Calculate baud rate divisors
504 * @clk: UART module input clock
505 * @baud: Desired baud rate
506 * @rbdiv: BDIV value (return value)
507 * @rcd: CD value (return value)
508 * @div8: Value for clk_sel bit in mod (return value)
509 * Return: baud rate, requested baud when possible, or actual baud when there
510 * was too much error, zero if no valid divisors are found.
511 *
512 * Formula to obtain baud rate is
513 * baud_tx/rx rate = clk/CD * (BDIV + 1)
514 * input_clk = (Uart User Defined Clock or Apb Clock)
515 * depends on UCLKEN in MR Reg
516 * clk = input_clk or input_clk/8;
517 * depends on CLKS in MR reg
518 * CD and BDIV depends on values in
519 * baud rate generate register
520 * baud rate clock divisor register
521 */
cdns_uart_calc_baud_divs(unsigned int clk,unsigned int baud,u32 * rbdiv,u32 * rcd,int * div8)522 static unsigned int cdns_uart_calc_baud_divs(unsigned int clk,
523 unsigned int baud, u32 *rbdiv, u32 *rcd, int *div8)
524 {
525 u32 cd, bdiv;
526 unsigned int calc_baud;
527 unsigned int bestbaud = 0;
528 unsigned int bauderror;
529 unsigned int besterror = ~0;
530
531 if (baud < clk / ((CDNS_UART_BDIV_MAX + 1) * CDNS_UART_CD_MAX)) {
532 *div8 = 1;
533 clk /= 8;
534 } else {
535 *div8 = 0;
536 }
537
538 for (bdiv = CDNS_UART_BDIV_MIN; bdiv <= CDNS_UART_BDIV_MAX; bdiv++) {
539 cd = DIV_ROUND_CLOSEST(clk, baud * (bdiv + 1));
540 if (cd < 1 || cd > CDNS_UART_CD_MAX)
541 continue;
542
543 calc_baud = clk / (cd * (bdiv + 1));
544
545 if (baud > calc_baud)
546 bauderror = baud - calc_baud;
547 else
548 bauderror = calc_baud - baud;
549
550 if (besterror > bauderror) {
551 *rbdiv = bdiv;
552 *rcd = cd;
553 bestbaud = calc_baud;
554 besterror = bauderror;
555 }
556 }
557 /* use the values when percent error is acceptable */
558 if (((besterror * 100) / baud) < 3)
559 bestbaud = baud;
560
561 return bestbaud;
562 }
563
564 /**
565 * cdns_uart_set_baud_rate - Calculate and set the baud rate
566 * @port: Handle to the uart port structure
567 * @baud: Baud rate to set
568 * Return: baud rate, requested baud when possible, or actual baud when there
569 * was too much error, zero if no valid divisors are found.
570 */
cdns_uart_set_baud_rate(struct uart_port * port,unsigned int baud)571 static unsigned int cdns_uart_set_baud_rate(struct uart_port *port,
572 unsigned int baud)
573 {
574 unsigned int calc_baud;
575 u32 cd = 0, bdiv = 0;
576 u32 mreg;
577 int div8;
578 struct cdns_uart *cdns_uart = port->private_data;
579
580 calc_baud = cdns_uart_calc_baud_divs(port->uartclk, baud, &bdiv, &cd,
581 &div8);
582
583 /* Write new divisors to hardware */
584 mreg = readl(port->membase + CDNS_UART_MR);
585 if (div8)
586 mreg |= CDNS_UART_MR_CLKSEL;
587 else
588 mreg &= ~CDNS_UART_MR_CLKSEL;
589 writel(mreg, port->membase + CDNS_UART_MR);
590 writel(cd, port->membase + CDNS_UART_BAUDGEN);
591 writel(bdiv, port->membase + CDNS_UART_BAUDDIV);
592 cdns_uart->baud = baud;
593
594 return calc_baud;
595 }
596
597 #ifdef CONFIG_COMMON_CLK
598 /**
599 * cdns_uart_clk_notifier_cb - Clock notifier callback
600 * @nb: Notifier block
601 * @event: Notify event
602 * @data: Notifier data
603 * Return: NOTIFY_OK or NOTIFY_DONE on success, NOTIFY_BAD on error.
604 */
cdns_uart_clk_notifier_cb(struct notifier_block * nb,unsigned long event,void * data)605 static int cdns_uart_clk_notifier_cb(struct notifier_block *nb,
606 unsigned long event, void *data)
607 {
608 u32 ctrl_reg;
609 struct uart_port *port;
610 int locked = 0;
611 struct clk_notifier_data *ndata = data;
612 struct cdns_uart *cdns_uart = to_cdns_uart(nb);
613 unsigned long flags;
614
615 port = cdns_uart->port;
616 if (port->suspended)
617 return NOTIFY_OK;
618
619 switch (event) {
620 case PRE_RATE_CHANGE:
621 {
622 u32 bdiv, cd;
623 int div8;
624
625 /*
626 * Find out if current baud-rate can be achieved with new clock
627 * frequency.
628 */
629 if (!cdns_uart_calc_baud_divs(ndata->new_rate, cdns_uart->baud,
630 &bdiv, &cd, &div8)) {
631 dev_warn(port->dev, "clock rate change rejected\n");
632 return NOTIFY_BAD;
633 }
634
635 uart_port_lock_irqsave(cdns_uart->port, &flags);
636
637 /* Disable the TX and RX to set baud rate */
638 ctrl_reg = readl(port->membase + CDNS_UART_CR);
639 ctrl_reg |= CDNS_UART_CR_TX_DIS | CDNS_UART_CR_RX_DIS;
640 writel(ctrl_reg, port->membase + CDNS_UART_CR);
641
642 uart_port_unlock_irqrestore(cdns_uart->port, flags);
643
644 return NOTIFY_OK;
645 }
646 case POST_RATE_CHANGE:
647 /*
648 * Set clk dividers to generate correct baud with new clock
649 * frequency.
650 */
651
652 uart_port_lock_irqsave(cdns_uart->port, &flags);
653
654 locked = 1;
655 port->uartclk = ndata->new_rate;
656
657 cdns_uart->baud = cdns_uart_set_baud_rate(cdns_uart->port,
658 cdns_uart->baud);
659 fallthrough;
660 case ABORT_RATE_CHANGE:
661 if (!locked)
662 uart_port_lock_irqsave(cdns_uart->port, &flags);
663
664 /* Set TX/RX Reset */
665 ctrl_reg = readl(port->membase + CDNS_UART_CR);
666 ctrl_reg |= CDNS_UART_CR_TXRST | CDNS_UART_CR_RXRST;
667 writel(ctrl_reg, port->membase + CDNS_UART_CR);
668
669 while (readl(port->membase + CDNS_UART_CR) &
670 (CDNS_UART_CR_TXRST | CDNS_UART_CR_RXRST))
671 cpu_relax();
672
673 /*
674 * Clear the RX disable and TX disable bits and then set the TX
675 * enable bit and RX enable bit to enable the transmitter and
676 * receiver.
677 */
678 writel(rx_timeout, port->membase + CDNS_UART_RXTOUT);
679 ctrl_reg = readl(port->membase + CDNS_UART_CR);
680 ctrl_reg &= ~(CDNS_UART_CR_TX_DIS | CDNS_UART_CR_RX_DIS);
681 ctrl_reg |= CDNS_UART_CR_TX_EN | CDNS_UART_CR_RX_EN;
682 writel(ctrl_reg, port->membase + CDNS_UART_CR);
683
684 uart_port_unlock_irqrestore(cdns_uart->port, flags);
685
686 return NOTIFY_OK;
687 default:
688 return NOTIFY_DONE;
689 }
690 }
691 #endif
692
693 /**
694 * cdns_rs485_tx_callback - Timer tx callback handler for rs485.
695 * @t: Handle to the hrtimer structure
696 */
cdns_rs485_tx_callback(struct hrtimer * t)697 static enum hrtimer_restart cdns_rs485_tx_callback(struct hrtimer *t)
698 {
699 struct cdns_uart *cdns_uart = container_of(t, struct cdns_uart, tx_timer);
700
701 uart_port_lock(cdns_uart->port);
702 cdns_uart_handle_tx(cdns_uart->port);
703 uart_port_unlock(cdns_uart->port);
704
705 return HRTIMER_NORESTART;
706 }
707
708 /**
709 * cdns_uart_start_tx - Start transmitting bytes
710 * @port: Handle to the uart port structure
711 */
cdns_uart_start_tx(struct uart_port * port)712 static void cdns_uart_start_tx(struct uart_port *port)
713 {
714 unsigned int status;
715 struct cdns_uart *cdns_uart = port->private_data;
716
717 if (uart_tx_stopped(port))
718 return;
719
720 /*
721 * Set the TX enable bit and clear the TX disable bit to enable the
722 * transmitter.
723 */
724 status = readl(port->membase + CDNS_UART_CR);
725 status &= ~CDNS_UART_CR_TX_DIS;
726 status |= CDNS_UART_CR_TX_EN;
727 writel(status, port->membase + CDNS_UART_CR);
728
729 if (kfifo_is_empty(&port->state->port.xmit_fifo))
730 return;
731
732 /* Clear the TX Empty interrupt */
733 writel(CDNS_UART_IXR_TXEMPTY, port->membase + CDNS_UART_ISR);
734
735 if (cdns_uart->port->rs485.flags & SER_RS485_ENABLED) {
736 if (!cdns_uart->rs485_tx_started) {
737 cdns_uart->tx_timer.function = &cdns_rs485_tx_callback;
738 cdns_rs485_tx_setup(cdns_uart);
739 return hrtimer_start(&cdns_uart->tx_timer,
740 ms_to_ktime(port->rs485.delay_rts_before_send),
741 HRTIMER_MODE_REL);
742 }
743 }
744 cdns_uart_handle_tx(port);
745 }
746
747 /**
748 * cdns_uart_stop_tx - Stop TX
749 * @port: Handle to the uart port structure
750 */
cdns_uart_stop_tx(struct uart_port * port)751 static void cdns_uart_stop_tx(struct uart_port *port)
752 {
753 unsigned int regval;
754 struct cdns_uart *cdns_uart = port->private_data;
755
756 if (cdns_uart->port->rs485.flags & SER_RS485_ENABLED)
757 cdns_rs485_rx_setup(cdns_uart);
758
759 regval = readl(port->membase + CDNS_UART_CR);
760 regval |= CDNS_UART_CR_TX_DIS;
761 /* Disable the transmitter */
762 writel(regval, port->membase + CDNS_UART_CR);
763 }
764
765 /**
766 * cdns_uart_stop_rx - Stop RX
767 * @port: Handle to the uart port structure
768 */
cdns_uart_stop_rx(struct uart_port * port)769 static void cdns_uart_stop_rx(struct uart_port *port)
770 {
771 unsigned int regval;
772
773 /* Disable RX IRQs */
774 writel(CDNS_UART_RX_IRQS, port->membase + CDNS_UART_IDR);
775
776 /* Disable the receiver */
777 regval = readl(port->membase + CDNS_UART_CR);
778 regval |= CDNS_UART_CR_RX_DIS;
779 writel(regval, port->membase + CDNS_UART_CR);
780 }
781
782 /**
783 * cdns_uart_break_ctl - Based on the input ctl we have to start or stop
784 * transmitting char breaks
785 * @port: Handle to the uart port structure
786 * @ctl: Value based on which start or stop decision is taken
787 */
cdns_uart_break_ctl(struct uart_port * port,int ctl)788 static void cdns_uart_break_ctl(struct uart_port *port, int ctl)
789 {
790 unsigned int status;
791 unsigned long flags;
792
793 uart_port_lock_irqsave(port, &flags);
794
795 status = readl(port->membase + CDNS_UART_CR);
796
797 if (ctl == -1)
798 writel(CDNS_UART_CR_STARTBRK | (~CDNS_UART_CR_STOPBRK & status),
799 port->membase + CDNS_UART_CR);
800 else {
801 if ((status & CDNS_UART_CR_STOPBRK) == 0)
802 writel(CDNS_UART_CR_STOPBRK | status,
803 port->membase + CDNS_UART_CR);
804 }
805 uart_port_unlock_irqrestore(port, flags);
806 }
807
808 /**
809 * cdns_uart_set_termios - termios operations, handling data length, parity,
810 * stop bits, flow control, baud rate
811 * @port: Handle to the uart port structure
812 * @termios: Handle to the input termios structure
813 * @old: Values of the previously saved termios structure
814 */
cdns_uart_set_termios(struct uart_port * port,struct ktermios * termios,const struct ktermios * old)815 static void cdns_uart_set_termios(struct uart_port *port,
816 struct ktermios *termios,
817 const struct ktermios *old)
818 {
819 u32 cval = 0;
820 unsigned int baud, minbaud, maxbaud;
821 unsigned long flags;
822 unsigned int ctrl_reg, mode_reg;
823
824 uart_port_lock_irqsave(port, &flags);
825
826 /* Disable the TX and RX to set baud rate */
827 ctrl_reg = readl(port->membase + CDNS_UART_CR);
828 ctrl_reg |= CDNS_UART_CR_TX_DIS | CDNS_UART_CR_RX_DIS;
829 writel(ctrl_reg, port->membase + CDNS_UART_CR);
830
831 /*
832 * Min baud rate = 6bps and Max Baud Rate is 10Mbps for 100Mhz clk
833 * min and max baud should be calculated here based on port->uartclk.
834 * this way we get a valid baud and can safely call set_baud()
835 */
836 minbaud = port->uartclk /
837 ((CDNS_UART_BDIV_MAX + 1) * CDNS_UART_CD_MAX * 8);
838 maxbaud = port->uartclk / (CDNS_UART_BDIV_MIN + 1);
839 baud = uart_get_baud_rate(port, termios, old, minbaud, maxbaud);
840 baud = cdns_uart_set_baud_rate(port, baud);
841 if (tty_termios_baud_rate(termios))
842 tty_termios_encode_baud_rate(termios, baud, baud);
843
844 /* Update the per-port timeout. */
845 uart_update_timeout(port, termios->c_cflag, baud);
846
847 /* Set TX/RX Reset */
848 ctrl_reg = readl(port->membase + CDNS_UART_CR);
849 ctrl_reg |= CDNS_UART_CR_TXRST | CDNS_UART_CR_RXRST;
850 writel(ctrl_reg, port->membase + CDNS_UART_CR);
851
852 while (readl(port->membase + CDNS_UART_CR) &
853 (CDNS_UART_CR_TXRST | CDNS_UART_CR_RXRST))
854 cpu_relax();
855
856 /*
857 * Clear the RX disable and TX disable bits and then set the TX enable
858 * bit and RX enable bit to enable the transmitter and receiver.
859 */
860 ctrl_reg = readl(port->membase + CDNS_UART_CR);
861 ctrl_reg &= ~(CDNS_UART_CR_TX_DIS | CDNS_UART_CR_RX_DIS);
862 ctrl_reg |= CDNS_UART_CR_TX_EN | CDNS_UART_CR_RX_EN;
863 writel(ctrl_reg, port->membase + CDNS_UART_CR);
864
865 writel(rx_timeout, port->membase + CDNS_UART_RXTOUT);
866
867 port->read_status_mask = CDNS_UART_IXR_TXEMPTY | CDNS_UART_IXR_RXTRIG |
868 CDNS_UART_IXR_OVERRUN | CDNS_UART_IXR_TOUT;
869 port->ignore_status_mask = 0;
870
871 if (termios->c_iflag & INPCK)
872 port->read_status_mask |= CDNS_UART_IXR_PARITY |
873 CDNS_UART_IXR_FRAMING;
874
875 if (termios->c_iflag & IGNPAR)
876 port->ignore_status_mask |= CDNS_UART_IXR_PARITY |
877 CDNS_UART_IXR_FRAMING | CDNS_UART_IXR_OVERRUN;
878
879 /* ignore all characters if CREAD is not set */
880 if ((termios->c_cflag & CREAD) == 0)
881 port->ignore_status_mask |= CDNS_UART_IXR_RXTRIG |
882 CDNS_UART_IXR_TOUT | CDNS_UART_IXR_PARITY |
883 CDNS_UART_IXR_FRAMING | CDNS_UART_IXR_OVERRUN;
884
885 mode_reg = readl(port->membase + CDNS_UART_MR);
886
887 /* Handling Data Size */
888 switch (termios->c_cflag & CSIZE) {
889 case CS6:
890 cval |= CDNS_UART_MR_CHARLEN_6_BIT;
891 break;
892 case CS7:
893 cval |= CDNS_UART_MR_CHARLEN_7_BIT;
894 break;
895 default:
896 case CS8:
897 cval |= CDNS_UART_MR_CHARLEN_8_BIT;
898 termios->c_cflag &= ~CSIZE;
899 termios->c_cflag |= CS8;
900 break;
901 }
902
903 /* Handling Parity and Stop Bits length */
904 if (termios->c_cflag & CSTOPB)
905 cval |= CDNS_UART_MR_STOPMODE_2_BIT; /* 2 STOP bits */
906 else
907 cval |= CDNS_UART_MR_STOPMODE_1_BIT; /* 1 STOP bit */
908
909 if (termios->c_cflag & PARENB) {
910 /* Mark or Space parity */
911 if (termios->c_cflag & CMSPAR) {
912 if (termios->c_cflag & PARODD)
913 cval |= CDNS_UART_MR_PARITY_MARK;
914 else
915 cval |= CDNS_UART_MR_PARITY_SPACE;
916 } else {
917 if (termios->c_cflag & PARODD)
918 cval |= CDNS_UART_MR_PARITY_ODD;
919 else
920 cval |= CDNS_UART_MR_PARITY_EVEN;
921 }
922 } else {
923 cval |= CDNS_UART_MR_PARITY_NONE;
924 }
925 cval |= mode_reg & 1;
926 writel(cval, port->membase + CDNS_UART_MR);
927
928 cval = readl(port->membase + CDNS_UART_MODEMCR);
929 if (termios->c_cflag & CRTSCTS)
930 cval |= CDNS_UART_MODEMCR_FCM;
931 else
932 cval &= ~CDNS_UART_MODEMCR_FCM;
933 writel(cval, port->membase + CDNS_UART_MODEMCR);
934
935 uart_port_unlock_irqrestore(port, flags);
936 }
937
938 /**
939 * cdns_uart_startup - Called when an application opens a cdns_uart port
940 * @port: Handle to the uart port structure
941 *
942 * Return: 0 on success, negative errno otherwise
943 */
cdns_uart_startup(struct uart_port * port)944 static int cdns_uart_startup(struct uart_port *port)
945 {
946 struct cdns_uart *cdns_uart = port->private_data;
947 bool is_brk_support;
948 int ret;
949 unsigned long flags;
950 unsigned int status = 0;
951
952 is_brk_support = cdns_uart->quirks & CDNS_UART_RXBS_SUPPORT;
953
954 ret = reset_control_deassert(cdns_uart->rstc);
955 if (ret)
956 return ret;
957
958 uart_port_lock_irqsave(port, &flags);
959
960 /* Disable the TX and RX */
961 writel(CDNS_UART_CR_TX_DIS | CDNS_UART_CR_RX_DIS,
962 port->membase + CDNS_UART_CR);
963
964 /* Set the Control Register with TX/RX Enable, TX/RX Reset,
965 * no break chars.
966 */
967 writel(CDNS_UART_CR_TXRST | CDNS_UART_CR_RXRST,
968 port->membase + CDNS_UART_CR);
969
970 while (readl(port->membase + CDNS_UART_CR) &
971 (CDNS_UART_CR_TXRST | CDNS_UART_CR_RXRST))
972 cpu_relax();
973
974 if (cdns_uart->port->rs485.flags & SER_RS485_ENABLED)
975 cdns_rs485_rx_setup(cdns_uart);
976
977 /*
978 * Clear the RX disable bit and then set the RX enable bit to enable
979 * the receiver.
980 */
981 status = readl(port->membase + CDNS_UART_CR);
982 status &= ~CDNS_UART_CR_RX_DIS;
983 status |= CDNS_UART_CR_RX_EN;
984 writel(status, port->membase + CDNS_UART_CR);
985
986 /* Set the Mode Register with normal mode,8 data bits,1 stop bit,
987 * no parity.
988 */
989 writel(CDNS_UART_MR_CHMODE_NORM | CDNS_UART_MR_STOPMODE_1_BIT
990 | CDNS_UART_MR_PARITY_NONE | CDNS_UART_MR_CHARLEN_8_BIT,
991 port->membase + CDNS_UART_MR);
992
993 /*
994 * Set the RX FIFO Trigger level to use most of the FIFO, but it
995 * can be tuned with a module parameter
996 */
997 writel(rx_trigger_level, port->membase + CDNS_UART_RXWM);
998
999 /*
1000 * Receive Timeout register is enabled but it
1001 * can be tuned with a module parameter
1002 */
1003 writel(rx_timeout, port->membase + CDNS_UART_RXTOUT);
1004
1005 /* Clear out any pending interrupts before enabling them */
1006 writel(readl(port->membase + CDNS_UART_ISR),
1007 port->membase + CDNS_UART_ISR);
1008
1009 uart_port_unlock_irqrestore(port, flags);
1010
1011 ret = request_irq(port->irq, cdns_uart_isr, 0, CDNS_UART_NAME, port);
1012 if (ret) {
1013 dev_err(port->dev, "request_irq '%d' failed with %d\n",
1014 port->irq, ret);
1015 return ret;
1016 }
1017
1018 /* Set the Interrupt Registers with desired interrupts */
1019 if (is_brk_support)
1020 writel(CDNS_UART_RX_IRQS | CDNS_UART_IXR_BRK,
1021 port->membase + CDNS_UART_IER);
1022 else
1023 writel(CDNS_UART_RX_IRQS, port->membase + CDNS_UART_IER);
1024
1025 return 0;
1026 }
1027
1028 /**
1029 * cdns_uart_shutdown - Called when an application closes a cdns_uart port
1030 * @port: Handle to the uart port structure
1031 */
cdns_uart_shutdown(struct uart_port * port)1032 static void cdns_uart_shutdown(struct uart_port *port)
1033 {
1034 int status;
1035 unsigned long flags;
1036 struct cdns_uart *cdns_uart = port->private_data;
1037
1038 if (cdns_uart->port->rs485.flags & SER_RS485_ENABLED)
1039 hrtimer_cancel(&cdns_uart->tx_timer);
1040
1041 uart_port_lock_irqsave(port, &flags);
1042
1043 /* Disable interrupts */
1044 status = readl(port->membase + CDNS_UART_IMR);
1045 writel(status, port->membase + CDNS_UART_IDR);
1046 writel(0xffffffff, port->membase + CDNS_UART_ISR);
1047
1048 /* Disable the TX and RX */
1049 writel(CDNS_UART_CR_TX_DIS | CDNS_UART_CR_RX_DIS,
1050 port->membase + CDNS_UART_CR);
1051
1052 uart_port_unlock_irqrestore(port, flags);
1053
1054 free_irq(port->irq, port);
1055 }
1056
1057 /**
1058 * cdns_uart_type - Set UART type to cdns_uart port
1059 * @port: Handle to the uart port structure
1060 *
1061 * Return: string on success, NULL otherwise
1062 */
cdns_uart_type(struct uart_port * port)1063 static const char *cdns_uart_type(struct uart_port *port)
1064 {
1065 return port->type == PORT_XUARTPS ? CDNS_UART_NAME : NULL;
1066 }
1067
1068 /**
1069 * cdns_uart_verify_port - Verify the port params
1070 * @port: Handle to the uart port structure
1071 * @ser: Handle to the structure whose members are compared
1072 *
1073 * Return: 0 on success, negative errno otherwise.
1074 */
cdns_uart_verify_port(struct uart_port * port,struct serial_struct * ser)1075 static int cdns_uart_verify_port(struct uart_port *port,
1076 struct serial_struct *ser)
1077 {
1078 if (ser->type != PORT_UNKNOWN && ser->type != PORT_XUARTPS)
1079 return -EINVAL;
1080 if (port->irq != ser->irq)
1081 return -EINVAL;
1082 if (ser->io_type != UPIO_MEM)
1083 return -EINVAL;
1084 if (port->iobase != ser->port)
1085 return -EINVAL;
1086 if (ser->hub6 != 0)
1087 return -EINVAL;
1088 return 0;
1089 }
1090
1091 /**
1092 * cdns_uart_request_port - Claim the memory region attached to cdns_uart port,
1093 * called when the driver adds a cdns_uart port via
1094 * uart_add_one_port()
1095 * @port: Handle to the uart port structure
1096 *
1097 * Return: 0 on success, negative errno otherwise.
1098 */
cdns_uart_request_port(struct uart_port * port)1099 static int cdns_uart_request_port(struct uart_port *port)
1100 {
1101 if (!request_mem_region(port->mapbase, CDNS_UART_REGISTER_SPACE,
1102 CDNS_UART_NAME)) {
1103 return -ENOMEM;
1104 }
1105
1106 port->membase = ioremap(port->mapbase, CDNS_UART_REGISTER_SPACE);
1107 if (!port->membase) {
1108 dev_err(port->dev, "Unable to map registers\n");
1109 release_mem_region(port->mapbase, CDNS_UART_REGISTER_SPACE);
1110 return -ENOMEM;
1111 }
1112 return 0;
1113 }
1114
1115 /**
1116 * cdns_uart_release_port - Release UART port
1117 * @port: Handle to the uart port structure
1118 *
1119 * Release the memory region attached to a cdns_uart port. Called when the
1120 * driver removes a cdns_uart port via uart_remove_one_port().
1121 */
cdns_uart_release_port(struct uart_port * port)1122 static void cdns_uart_release_port(struct uart_port *port)
1123 {
1124 release_mem_region(port->mapbase, CDNS_UART_REGISTER_SPACE);
1125 iounmap(port->membase);
1126 port->membase = NULL;
1127 }
1128
1129 /**
1130 * cdns_uart_config_port - Configure UART port
1131 * @port: Handle to the uart port structure
1132 * @flags: If any
1133 */
cdns_uart_config_port(struct uart_port * port,int flags)1134 static void cdns_uart_config_port(struct uart_port *port, int flags)
1135 {
1136 if (flags & UART_CONFIG_TYPE && cdns_uart_request_port(port) == 0)
1137 port->type = PORT_XUARTPS;
1138 }
1139
1140 /**
1141 * cdns_uart_get_mctrl - Get the modem control state
1142 * @port: Handle to the uart port structure
1143 *
1144 * Return: the modem control state
1145 */
cdns_uart_get_mctrl(struct uart_port * port)1146 static unsigned int cdns_uart_get_mctrl(struct uart_port *port)
1147 {
1148 u32 val;
1149 unsigned int mctrl = 0;
1150 struct cdns_uart *cdns_uart_data = port->private_data;
1151
1152 if (cdns_uart_data->cts_override)
1153 return TIOCM_CTS | TIOCM_DSR | TIOCM_CAR;
1154
1155 val = readl(port->membase + CDNS_UART_MODEMSR);
1156 if (val & CDNS_UART_MODEMSR_CTS)
1157 mctrl |= TIOCM_CTS;
1158 if (val & CDNS_UART_MODEMSR_DSR)
1159 mctrl |= TIOCM_DSR;
1160 if (val & CDNS_UART_MODEMSR_RI)
1161 mctrl |= TIOCM_RNG;
1162 if (val & CDNS_UART_MODEMSR_DCD)
1163 mctrl |= TIOCM_CAR;
1164
1165 return mctrl;
1166 }
1167
cdns_uart_set_mctrl(struct uart_port * port,unsigned int mctrl)1168 static void cdns_uart_set_mctrl(struct uart_port *port, unsigned int mctrl)
1169 {
1170 u32 val;
1171 u32 mode_reg;
1172 struct cdns_uart *cdns_uart_data = port->private_data;
1173
1174 if (cdns_uart_data->cts_override)
1175 return;
1176
1177 val = readl(port->membase + CDNS_UART_MODEMCR);
1178 mode_reg = readl(port->membase + CDNS_UART_MR);
1179
1180 val &= ~(CDNS_UART_MODEMCR_RTS | CDNS_UART_MODEMCR_DTR);
1181 mode_reg &= ~CDNS_UART_MR_CHMODE_MASK;
1182
1183 if (mctrl & TIOCM_RTS)
1184 val |= CDNS_UART_MODEMCR_RTS;
1185 if (cdns_uart_data->gpiod_rts)
1186 gpiod_set_value(cdns_uart_data->gpiod_rts, !(mctrl & TIOCM_RTS));
1187 if (mctrl & TIOCM_DTR)
1188 val |= CDNS_UART_MODEMCR_DTR;
1189 if (mctrl & TIOCM_LOOP)
1190 mode_reg |= CDNS_UART_MR_CHMODE_L_LOOP;
1191 else
1192 mode_reg |= CDNS_UART_MR_CHMODE_NORM;
1193
1194 writel(val, port->membase + CDNS_UART_MODEMCR);
1195 writel(mode_reg, port->membase + CDNS_UART_MR);
1196 }
1197
1198 #ifdef CONFIG_CONSOLE_POLL
cdns_uart_poll_get_char(struct uart_port * port)1199 static int cdns_uart_poll_get_char(struct uart_port *port)
1200 {
1201 int c;
1202 unsigned long flags;
1203
1204 uart_port_lock_irqsave(port, &flags);
1205
1206 /* Check if FIFO is empty */
1207 if (readl(port->membase + CDNS_UART_SR) & CDNS_UART_SR_RXEMPTY)
1208 c = NO_POLL_CHAR;
1209 else /* Read a character */
1210 c = (unsigned char) readl(port->membase + CDNS_UART_FIFO);
1211
1212 uart_port_unlock_irqrestore(port, flags);
1213
1214 return c;
1215 }
1216
cdns_uart_poll_put_char(struct uart_port * port,unsigned char c)1217 static void cdns_uart_poll_put_char(struct uart_port *port, unsigned char c)
1218 {
1219 unsigned long flags;
1220
1221 uart_port_lock_irqsave(port, &flags);
1222
1223 /* Wait until FIFO is empty */
1224 while (!(readl(port->membase + CDNS_UART_SR) & CDNS_UART_SR_TXEMPTY))
1225 cpu_relax();
1226
1227 /* Write a character */
1228 writel(c, port->membase + CDNS_UART_FIFO);
1229
1230 /* Wait until FIFO is empty */
1231 while (!(readl(port->membase + CDNS_UART_SR) & CDNS_UART_SR_TXEMPTY))
1232 cpu_relax();
1233
1234 uart_port_unlock_irqrestore(port, flags);
1235 }
1236 #endif
1237
cdns_uart_pm(struct uart_port * port,unsigned int state,unsigned int oldstate)1238 static void cdns_uart_pm(struct uart_port *port, unsigned int state,
1239 unsigned int oldstate)
1240 {
1241 switch (state) {
1242 case UART_PM_STATE_OFF:
1243 pm_runtime_mark_last_busy(port->dev);
1244 pm_runtime_put_autosuspend(port->dev);
1245 break;
1246 default:
1247 pm_runtime_get_sync(port->dev);
1248 break;
1249 }
1250 }
1251
1252 static const struct uart_ops cdns_uart_ops = {
1253 .set_mctrl = cdns_uart_set_mctrl,
1254 .get_mctrl = cdns_uart_get_mctrl,
1255 .start_tx = cdns_uart_start_tx,
1256 .stop_tx = cdns_uart_stop_tx,
1257 .stop_rx = cdns_uart_stop_rx,
1258 .tx_empty = cdns_uart_tx_empty,
1259 .break_ctl = cdns_uart_break_ctl,
1260 .set_termios = cdns_uart_set_termios,
1261 .startup = cdns_uart_startup,
1262 .shutdown = cdns_uart_shutdown,
1263 .pm = cdns_uart_pm,
1264 .type = cdns_uart_type,
1265 .verify_port = cdns_uart_verify_port,
1266 .request_port = cdns_uart_request_port,
1267 .release_port = cdns_uart_release_port,
1268 .config_port = cdns_uart_config_port,
1269 #ifdef CONFIG_CONSOLE_POLL
1270 .poll_get_char = cdns_uart_poll_get_char,
1271 .poll_put_char = cdns_uart_poll_put_char,
1272 #endif
1273 };
1274
1275 static struct uart_driver cdns_uart_uart_driver;
1276
1277 #ifdef CONFIG_SERIAL_XILINX_PS_UART_CONSOLE
1278 /**
1279 * cdns_uart_console_putchar - write the character to the FIFO buffer
1280 * @port: Handle to the uart port structure
1281 * @ch: Character to be written
1282 */
cdns_uart_console_putchar(struct uart_port * port,unsigned char ch)1283 static void cdns_uart_console_putchar(struct uart_port *port, unsigned char ch)
1284 {
1285 unsigned int ctrl_reg;
1286 unsigned long timeout;
1287
1288 timeout = jiffies + msecs_to_jiffies(1000);
1289 while (1) {
1290 ctrl_reg = readl(port->membase + CDNS_UART_CR);
1291 if (!(ctrl_reg & CDNS_UART_CR_TX_DIS))
1292 break;
1293 if (time_after(jiffies, timeout)) {
1294 dev_warn(port->dev,
1295 "timeout waiting for Enable\n");
1296 return;
1297 }
1298 cpu_relax();
1299 }
1300
1301 timeout = jiffies + msecs_to_jiffies(1000);
1302 while (1) {
1303 ctrl_reg = readl(port->membase + CDNS_UART_SR);
1304
1305 if (!(ctrl_reg & CDNS_UART_SR_TXFULL))
1306 break;
1307 if (time_after(jiffies, timeout)) {
1308 dev_warn(port->dev,
1309 "timeout waiting for TX fifo\n");
1310 return;
1311 }
1312 cpu_relax();
1313 }
1314 writel(ch, port->membase + CDNS_UART_FIFO);
1315 }
1316
cdns_early_write(struct console * con,const char * s,unsigned int n)1317 static void cdns_early_write(struct console *con, const char *s,
1318 unsigned int n)
1319 {
1320 struct earlycon_device *dev = con->data;
1321
1322 uart_console_write(&dev->port, s, n, cdns_uart_console_putchar);
1323 }
1324
cdns_early_console_setup(struct earlycon_device * device,const char * opt)1325 static int __init cdns_early_console_setup(struct earlycon_device *device,
1326 const char *opt)
1327 {
1328 struct uart_port *port = &device->port;
1329
1330 if (!port->membase)
1331 return -ENODEV;
1332
1333 /* initialise control register */
1334 writel(CDNS_UART_CR_TX_EN|CDNS_UART_CR_TXRST|CDNS_UART_CR_RXRST,
1335 port->membase + CDNS_UART_CR);
1336
1337 /* only set baud if specified on command line - otherwise
1338 * assume it has been initialized by a boot loader.
1339 */
1340 if (port->uartclk && device->baud) {
1341 u32 cd = 0, bdiv = 0;
1342 u32 mr;
1343 int div8;
1344
1345 cdns_uart_calc_baud_divs(port->uartclk, device->baud,
1346 &bdiv, &cd, &div8);
1347 mr = CDNS_UART_MR_PARITY_NONE;
1348 if (div8)
1349 mr |= CDNS_UART_MR_CLKSEL;
1350
1351 writel(mr, port->membase + CDNS_UART_MR);
1352 writel(cd, port->membase + CDNS_UART_BAUDGEN);
1353 writel(bdiv, port->membase + CDNS_UART_BAUDDIV);
1354 }
1355
1356 device->con->write = cdns_early_write;
1357
1358 return 0;
1359 }
1360 OF_EARLYCON_DECLARE(cdns, "xlnx,xuartps", cdns_early_console_setup);
1361 OF_EARLYCON_DECLARE(cdns, "cdns,uart-r1p8", cdns_early_console_setup);
1362 OF_EARLYCON_DECLARE(cdns, "cdns,uart-r1p12", cdns_early_console_setup);
1363 OF_EARLYCON_DECLARE(cdns, "xlnx,zynqmp-uart", cdns_early_console_setup);
1364
1365
1366 /* Static pointer to console port */
1367 static struct uart_port *console_port;
1368
1369 /**
1370 * cdns_uart_console_write - perform write operation
1371 * @co: Console handle
1372 * @s: Pointer to character array
1373 * @count: No of characters
1374 */
cdns_uart_console_write(struct console * co,const char * s,unsigned int count)1375 static void cdns_uart_console_write(struct console *co, const char *s,
1376 unsigned int count)
1377 {
1378 struct uart_port *port = console_port;
1379 unsigned long flags;
1380 unsigned int imr, ctrl;
1381 int locked = 1;
1382
1383 if (port->sysrq)
1384 locked = 0;
1385 else if (oops_in_progress)
1386 locked = uart_port_trylock_irqsave(port, &flags);
1387 else
1388 uart_port_lock_irqsave(port, &flags);
1389
1390 /* save and disable interrupt */
1391 imr = readl(port->membase + CDNS_UART_IMR);
1392 writel(imr, port->membase + CDNS_UART_IDR);
1393
1394 /*
1395 * Make sure that the tx part is enabled. Set the TX enable bit and
1396 * clear the TX disable bit to enable the transmitter.
1397 */
1398 ctrl = readl(port->membase + CDNS_UART_CR);
1399 ctrl &= ~CDNS_UART_CR_TX_DIS;
1400 ctrl |= CDNS_UART_CR_TX_EN;
1401 writel(ctrl, port->membase + CDNS_UART_CR);
1402
1403 uart_console_write(port, s, count, cdns_uart_console_putchar);
1404 while (cdns_uart_tx_empty(port) != TIOCSER_TEMT)
1405 cpu_relax();
1406
1407 /* restore interrupt state */
1408 writel(imr, port->membase + CDNS_UART_IER);
1409
1410 if (locked)
1411 uart_port_unlock_irqrestore(port, flags);
1412 }
1413
1414 /**
1415 * cdns_uart_console_setup - Initialize the uart to default config
1416 * @co: Console handle
1417 * @options: Initial settings of uart
1418 *
1419 * Return: 0 on success, negative errno otherwise.
1420 */
cdns_uart_console_setup(struct console * co,char * options)1421 static int cdns_uart_console_setup(struct console *co, char *options)
1422 {
1423 struct uart_port *port = console_port;
1424
1425 int baud = 9600;
1426 int bits = 8;
1427 int parity = 'n';
1428 int flow = 'n';
1429 unsigned long time_out;
1430
1431 if (!port->membase) {
1432 pr_debug("console on " CDNS_UART_TTY_NAME "%i not present\n",
1433 co->index);
1434 return -ENODEV;
1435 }
1436
1437 if (options)
1438 uart_parse_options(options, &baud, &parity, &bits, &flow);
1439
1440 /* Wait for tx_empty before setting up the console */
1441 time_out = jiffies + usecs_to_jiffies(TX_TIMEOUT);
1442
1443 while (time_before(jiffies, time_out) &&
1444 cdns_uart_tx_empty(port) != TIOCSER_TEMT)
1445 cpu_relax();
1446
1447 return uart_set_options(port, co, baud, parity, bits, flow);
1448 }
1449
1450 static struct console cdns_uart_console = {
1451 .name = CDNS_UART_TTY_NAME,
1452 .write = cdns_uart_console_write,
1453 .device = uart_console_device,
1454 .setup = cdns_uart_console_setup,
1455 .flags = CON_PRINTBUFFER,
1456 .index = -1, /* Specified on the cmdline (e.g. console=ttyPS ) */
1457 .data = &cdns_uart_uart_driver,
1458 };
1459 #endif /* CONFIG_SERIAL_XILINX_PS_UART_CONSOLE */
1460
1461 #ifdef CONFIG_PM_SLEEP
1462 /**
1463 * cdns_uart_suspend - suspend event
1464 * @device: Pointer to the device structure
1465 *
1466 * Return: 0
1467 */
cdns_uart_suspend(struct device * device)1468 static int cdns_uart_suspend(struct device *device)
1469 {
1470 struct uart_port *port = dev_get_drvdata(device);
1471 struct cdns_uart *cdns_uart = port->private_data;
1472 int may_wake;
1473
1474 may_wake = device_may_wakeup(device);
1475
1476 if (console_suspend_enabled && uart_console(port) && may_wake) {
1477 unsigned long flags;
1478
1479 uart_port_lock_irqsave(port, &flags);
1480 /* Empty the receive FIFO 1st before making changes */
1481 while (!(readl(port->membase + CDNS_UART_SR) &
1482 CDNS_UART_SR_RXEMPTY))
1483 readl(port->membase + CDNS_UART_FIFO);
1484 /* set RX trigger level to 1 */
1485 writel(1, port->membase + CDNS_UART_RXWM);
1486 /* disable RX timeout interrups */
1487 writel(CDNS_UART_IXR_TOUT, port->membase + CDNS_UART_IDR);
1488 uart_port_unlock_irqrestore(port, flags);
1489 }
1490
1491 /*
1492 * Call the API provided in serial_core.c file which handles
1493 * the suspend.
1494 */
1495 return uart_suspend_port(cdns_uart->cdns_uart_driver, port);
1496 }
1497
1498 /**
1499 * cdns_uart_resume - Resume after a previous suspend
1500 * @device: Pointer to the device structure
1501 *
1502 * Return: 0
1503 */
cdns_uart_resume(struct device * device)1504 static int cdns_uart_resume(struct device *device)
1505 {
1506 struct uart_port *port = dev_get_drvdata(device);
1507 struct cdns_uart *cdns_uart = port->private_data;
1508 unsigned long flags;
1509 u32 ctrl_reg;
1510 int may_wake;
1511 int ret;
1512
1513 may_wake = device_may_wakeup(device);
1514
1515 if (console_suspend_enabled && uart_console(port) && !may_wake) {
1516 ret = clk_enable(cdns_uart->pclk);
1517 if (ret)
1518 return ret;
1519
1520 ret = clk_enable(cdns_uart->uartclk);
1521 if (ret) {
1522 clk_disable(cdns_uart->pclk);
1523 return ret;
1524 }
1525
1526 uart_port_lock_irqsave(port, &flags);
1527
1528 /* Set TX/RX Reset */
1529 ctrl_reg = readl(port->membase + CDNS_UART_CR);
1530 ctrl_reg |= CDNS_UART_CR_TXRST | CDNS_UART_CR_RXRST;
1531 writel(ctrl_reg, port->membase + CDNS_UART_CR);
1532 while (readl(port->membase + CDNS_UART_CR) &
1533 (CDNS_UART_CR_TXRST | CDNS_UART_CR_RXRST))
1534 cpu_relax();
1535
1536 /* restore rx timeout value */
1537 writel(rx_timeout, port->membase + CDNS_UART_RXTOUT);
1538 /* Enable Tx/Rx */
1539 ctrl_reg = readl(port->membase + CDNS_UART_CR);
1540 ctrl_reg &= ~(CDNS_UART_CR_TX_DIS | CDNS_UART_CR_RX_DIS);
1541 ctrl_reg |= CDNS_UART_CR_TX_EN | CDNS_UART_CR_RX_EN;
1542 writel(ctrl_reg, port->membase + CDNS_UART_CR);
1543
1544 clk_disable(cdns_uart->uartclk);
1545 clk_disable(cdns_uart->pclk);
1546 uart_port_unlock_irqrestore(port, flags);
1547 } else {
1548 uart_port_lock_irqsave(port, &flags);
1549 /* restore original rx trigger level */
1550 writel(rx_trigger_level, port->membase + CDNS_UART_RXWM);
1551 /* enable RX timeout interrupt */
1552 writel(CDNS_UART_IXR_TOUT, port->membase + CDNS_UART_IER);
1553 uart_port_unlock_irqrestore(port, flags);
1554 }
1555
1556 return uart_resume_port(cdns_uart->cdns_uart_driver, port);
1557 }
1558 #endif /* ! CONFIG_PM_SLEEP */
cdns_runtime_suspend(struct device * dev)1559 static int __maybe_unused cdns_runtime_suspend(struct device *dev)
1560 {
1561 struct uart_port *port = dev_get_drvdata(dev);
1562 struct cdns_uart *cdns_uart = port->private_data;
1563
1564 clk_disable(cdns_uart->uartclk);
1565 clk_disable(cdns_uart->pclk);
1566 return 0;
1567 };
1568
cdns_runtime_resume(struct device * dev)1569 static int __maybe_unused cdns_runtime_resume(struct device *dev)
1570 {
1571 struct uart_port *port = dev_get_drvdata(dev);
1572 struct cdns_uart *cdns_uart = port->private_data;
1573 int ret;
1574
1575 ret = clk_enable(cdns_uart->pclk);
1576 if (ret)
1577 return ret;
1578
1579 ret = clk_enable(cdns_uart->uartclk);
1580 if (ret) {
1581 clk_disable(cdns_uart->pclk);
1582 return ret;
1583 }
1584 return 0;
1585 };
1586
1587 static const struct dev_pm_ops cdns_uart_dev_pm_ops = {
1588 SET_SYSTEM_SLEEP_PM_OPS(cdns_uart_suspend, cdns_uart_resume)
1589 SET_RUNTIME_PM_OPS(cdns_runtime_suspend,
1590 cdns_runtime_resume, NULL)
1591 };
1592
1593 static const struct cdns_platform_data zynqmp_uart_def = {
1594 .quirks = CDNS_UART_RXBS_SUPPORT, };
1595
1596 /* Match table for of_platform binding */
1597 static const struct of_device_id cdns_uart_of_match[] = {
1598 { .compatible = "xlnx,xuartps", },
1599 { .compatible = "cdns,uart-r1p8", },
1600 { .compatible = "cdns,uart-r1p12", .data = &zynqmp_uart_def },
1601 { .compatible = "xlnx,zynqmp-uart", .data = &zynqmp_uart_def },
1602 {}
1603 };
1604 MODULE_DEVICE_TABLE(of, cdns_uart_of_match);
1605
1606 /* Temporary variable for storing number of instances */
1607 static int instances;
1608
1609 /**
1610 * cdns_rs485_config - Called when an application calls TIOCSRS485 ioctl.
1611 * @port: Pointer to the uart_port structure
1612 * @termios: Pointer to the ktermios structure
1613 * @rs485: Pointer to the serial_rs485 structure
1614 *
1615 * Return: 0
1616 */
cdns_rs485_config(struct uart_port * port,struct ktermios * termios,struct serial_rs485 * rs485)1617 static int cdns_rs485_config(struct uart_port *port, struct ktermios *termios,
1618 struct serial_rs485 *rs485)
1619 {
1620 u32 val;
1621 struct cdns_uart *cdns_uart = port->private_data;
1622
1623 if (rs485->flags & SER_RS485_ENABLED) {
1624 dev_dbg(port->dev, "Setting UART to RS485\n");
1625 /* Make sure auto RTS is disabled */
1626 val = readl(port->membase + CDNS_UART_MODEMCR);
1627 val &= ~CDNS_UART_MODEMCR_FCM;
1628 writel(val, port->membase + CDNS_UART_MODEMCR);
1629
1630 /* Timer setup */
1631 hrtimer_init(&cdns_uart->tx_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
1632 cdns_uart->tx_timer.function = &cdns_rs485_tx_callback;
1633
1634 /* Disable transmitter and make Rx setup*/
1635 cdns_uart_stop_tx(port);
1636 } else {
1637 hrtimer_cancel(&cdns_uart->tx_timer);
1638 }
1639 return 0;
1640 }
1641
1642 /**
1643 * cdns_uart_probe - Platform driver probe
1644 * @pdev: Pointer to the platform device structure
1645 *
1646 * Return: 0 on success, negative errno otherwise
1647 */
cdns_uart_probe(struct platform_device * pdev)1648 static int cdns_uart_probe(struct platform_device *pdev)
1649 {
1650 int rc, id, irq;
1651 struct uart_port *port;
1652 struct resource *res;
1653 struct cdns_uart *cdns_uart_data;
1654 const struct of_device_id *match;
1655
1656 cdns_uart_data = devm_kzalloc(&pdev->dev, sizeof(*cdns_uart_data),
1657 GFP_KERNEL);
1658 if (!cdns_uart_data)
1659 return -ENOMEM;
1660 port = devm_kzalloc(&pdev->dev, sizeof(*port), GFP_KERNEL);
1661 if (!port)
1662 return -ENOMEM;
1663
1664 /* Look for a serialN alias */
1665 id = of_alias_get_id(pdev->dev.of_node, "serial");
1666 if (id < 0)
1667 id = 0;
1668
1669 if (id >= CDNS_UART_NR_PORTS) {
1670 dev_err(&pdev->dev, "Cannot get uart_port structure\n");
1671 return -ENODEV;
1672 }
1673
1674 if (!cdns_uart_uart_driver.state) {
1675 cdns_uart_uart_driver.owner = THIS_MODULE;
1676 cdns_uart_uart_driver.driver_name = CDNS_UART_NAME;
1677 cdns_uart_uart_driver.dev_name = CDNS_UART_TTY_NAME;
1678 cdns_uart_uart_driver.major = CDNS_UART_MAJOR;
1679 cdns_uart_uart_driver.minor = CDNS_UART_MINOR;
1680 cdns_uart_uart_driver.nr = CDNS_UART_NR_PORTS;
1681 #ifdef CONFIG_SERIAL_XILINX_PS_UART_CONSOLE
1682 cdns_uart_uart_driver.cons = &cdns_uart_console;
1683 #endif
1684
1685 rc = uart_register_driver(&cdns_uart_uart_driver);
1686 if (rc < 0) {
1687 dev_err(&pdev->dev, "Failed to register driver\n");
1688 return rc;
1689 }
1690 }
1691
1692 cdns_uart_data->cdns_uart_driver = &cdns_uart_uart_driver;
1693
1694 match = of_match_node(cdns_uart_of_match, pdev->dev.of_node);
1695 if (match && match->data) {
1696 const struct cdns_platform_data *data = match->data;
1697
1698 cdns_uart_data->quirks = data->quirks;
1699 }
1700
1701 cdns_uart_data->pclk = devm_clk_get(&pdev->dev, "pclk");
1702 if (PTR_ERR(cdns_uart_data->pclk) == -EPROBE_DEFER) {
1703 rc = PTR_ERR(cdns_uart_data->pclk);
1704 goto err_out_unregister_driver;
1705 }
1706
1707 if (IS_ERR(cdns_uart_data->pclk)) {
1708 cdns_uart_data->pclk = devm_clk_get(&pdev->dev, "aper_clk");
1709 if (IS_ERR(cdns_uart_data->pclk)) {
1710 rc = PTR_ERR(cdns_uart_data->pclk);
1711 goto err_out_unregister_driver;
1712 }
1713 dev_err(&pdev->dev, "clock name 'aper_clk' is deprecated.\n");
1714 }
1715
1716 cdns_uart_data->uartclk = devm_clk_get(&pdev->dev, "uart_clk");
1717 if (PTR_ERR(cdns_uart_data->uartclk) == -EPROBE_DEFER) {
1718 rc = PTR_ERR(cdns_uart_data->uartclk);
1719 goto err_out_unregister_driver;
1720 }
1721
1722 if (IS_ERR(cdns_uart_data->uartclk)) {
1723 cdns_uart_data->uartclk = devm_clk_get(&pdev->dev, "ref_clk");
1724 if (IS_ERR(cdns_uart_data->uartclk)) {
1725 rc = PTR_ERR(cdns_uart_data->uartclk);
1726 goto err_out_unregister_driver;
1727 }
1728 dev_err(&pdev->dev, "clock name 'ref_clk' is deprecated.\n");
1729 }
1730
1731 cdns_uart_data->rstc = devm_reset_control_get_optional_exclusive(&pdev->dev, NULL);
1732 if (IS_ERR(cdns_uart_data->rstc)) {
1733 rc = PTR_ERR(cdns_uart_data->rstc);
1734 dev_err_probe(&pdev->dev, rc, "Cannot get UART reset\n");
1735 goto err_out_unregister_driver;
1736 }
1737
1738 rc = clk_prepare_enable(cdns_uart_data->pclk);
1739 if (rc) {
1740 dev_err(&pdev->dev, "Unable to enable pclk clock.\n");
1741 goto err_out_unregister_driver;
1742 }
1743 rc = clk_prepare_enable(cdns_uart_data->uartclk);
1744 if (rc) {
1745 dev_err(&pdev->dev, "Unable to enable device clock.\n");
1746 goto err_out_clk_dis_pclk;
1747 }
1748
1749 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1750 if (!res) {
1751 rc = -ENODEV;
1752 goto err_out_clk_disable;
1753 }
1754
1755 irq = platform_get_irq(pdev, 0);
1756 if (irq < 0) {
1757 rc = irq;
1758 goto err_out_clk_disable;
1759 }
1760
1761 #ifdef CONFIG_COMMON_CLK
1762 cdns_uart_data->clk_rate_change_nb.notifier_call =
1763 cdns_uart_clk_notifier_cb;
1764 if (clk_notifier_register(cdns_uart_data->uartclk,
1765 &cdns_uart_data->clk_rate_change_nb))
1766 dev_warn(&pdev->dev, "Unable to register clock notifier.\n");
1767 #endif
1768
1769 /* At this point, we've got an empty uart_port struct, initialize it */
1770 spin_lock_init(&port->lock);
1771 port->type = PORT_UNKNOWN;
1772 port->iotype = UPIO_MEM32;
1773 port->flags = UPF_BOOT_AUTOCONF;
1774 port->ops = &cdns_uart_ops;
1775 port->fifosize = CDNS_UART_FIFO_SIZE;
1776 port->has_sysrq = IS_ENABLED(CONFIG_SERIAL_XILINX_PS_UART_CONSOLE);
1777 port->line = id;
1778
1779 /*
1780 * Register the port.
1781 * This function also registers this device with the tty layer
1782 * and triggers invocation of the config_port() entry point.
1783 */
1784 port->mapbase = res->start;
1785 port->irq = irq;
1786 port->dev = &pdev->dev;
1787 port->uartclk = clk_get_rate(cdns_uart_data->uartclk);
1788 port->private_data = cdns_uart_data;
1789 port->read_status_mask = CDNS_UART_IXR_TXEMPTY | CDNS_UART_IXR_RXTRIG |
1790 CDNS_UART_IXR_OVERRUN | CDNS_UART_IXR_TOUT;
1791 port->rs485_config = cdns_rs485_config;
1792 port->rs485_supported = cdns_rs485_supported;
1793 cdns_uart_data->port = port;
1794 platform_set_drvdata(pdev, port);
1795
1796 rc = uart_get_rs485_mode(port);
1797 if (rc)
1798 goto err_out_clk_notifier;
1799
1800 cdns_uart_data->gpiod_rts = devm_gpiod_get_optional(&pdev->dev, "rts",
1801 GPIOD_OUT_LOW);
1802 if (IS_ERR(cdns_uart_data->gpiod_rts)) {
1803 rc = PTR_ERR(cdns_uart_data->gpiod_rts);
1804 dev_err(port->dev, "xuartps: devm_gpiod_get_optional failed\n");
1805 goto err_out_clk_notifier;
1806 }
1807
1808 pm_runtime_use_autosuspend(&pdev->dev);
1809 pm_runtime_set_autosuspend_delay(&pdev->dev, UART_AUTOSUSPEND_TIMEOUT);
1810 pm_runtime_set_active(&pdev->dev);
1811 pm_runtime_enable(&pdev->dev);
1812 device_init_wakeup(port->dev, true);
1813
1814 #ifdef CONFIG_SERIAL_XILINX_PS_UART_CONSOLE
1815 /*
1816 * If console hasn't been found yet try to assign this port
1817 * because it is required to be assigned for console setup function.
1818 * If register_console() don't assign value, then console_port pointer
1819 * is cleanup.
1820 */
1821 if (!console_port) {
1822 cdns_uart_console.index = id;
1823 console_port = port;
1824 }
1825 #endif
1826 if (cdns_uart_data->port->rs485.flags & SER_RS485_ENABLED)
1827 cdns_rs485_rx_setup(cdns_uart_data);
1828
1829 rc = uart_add_one_port(&cdns_uart_uart_driver, port);
1830 if (rc) {
1831 dev_err(&pdev->dev,
1832 "uart_add_one_port() failed; err=%i\n", rc);
1833 goto err_out_pm_disable;
1834 }
1835
1836 #ifdef CONFIG_SERIAL_XILINX_PS_UART_CONSOLE
1837 /* This is not port which is used for console that's why clean it up */
1838 if (console_port == port &&
1839 !console_is_registered(cdns_uart_uart_driver.cons)) {
1840 console_port = NULL;
1841 cdns_uart_console.index = -1;
1842 }
1843 #endif
1844
1845 cdns_uart_data->cts_override = of_property_read_bool(pdev->dev.of_node,
1846 "cts-override");
1847
1848 instances++;
1849
1850 return 0;
1851
1852 err_out_pm_disable:
1853 pm_runtime_disable(&pdev->dev);
1854 pm_runtime_set_suspended(&pdev->dev);
1855 pm_runtime_dont_use_autosuspend(&pdev->dev);
1856 err_out_clk_notifier:
1857 #ifdef CONFIG_COMMON_CLK
1858 clk_notifier_unregister(cdns_uart_data->uartclk,
1859 &cdns_uart_data->clk_rate_change_nb);
1860 #endif
1861 err_out_clk_disable:
1862 clk_disable_unprepare(cdns_uart_data->uartclk);
1863 err_out_clk_dis_pclk:
1864 clk_disable_unprepare(cdns_uart_data->pclk);
1865 err_out_unregister_driver:
1866 if (!instances)
1867 uart_unregister_driver(cdns_uart_data->cdns_uart_driver);
1868 return rc;
1869 }
1870
1871 /**
1872 * cdns_uart_remove - called when the platform driver is unregistered
1873 * @pdev: Pointer to the platform device structure
1874 */
cdns_uart_remove(struct platform_device * pdev)1875 static void cdns_uart_remove(struct platform_device *pdev)
1876 {
1877 struct uart_port *port = platform_get_drvdata(pdev);
1878 struct cdns_uart *cdns_uart_data = port->private_data;
1879
1880 /* Remove the cdns_uart port from the serial core */
1881 #ifdef CONFIG_COMMON_CLK
1882 clk_notifier_unregister(cdns_uart_data->uartclk,
1883 &cdns_uart_data->clk_rate_change_nb);
1884 #endif
1885 uart_remove_one_port(cdns_uart_data->cdns_uart_driver, port);
1886 port->mapbase = 0;
1887 clk_disable_unprepare(cdns_uart_data->uartclk);
1888 clk_disable_unprepare(cdns_uart_data->pclk);
1889 pm_runtime_disable(&pdev->dev);
1890 pm_runtime_set_suspended(&pdev->dev);
1891 pm_runtime_dont_use_autosuspend(&pdev->dev);
1892 device_init_wakeup(&pdev->dev, false);
1893
1894 #ifdef CONFIG_SERIAL_XILINX_PS_UART_CONSOLE
1895 if (console_port == port)
1896 console_port = NULL;
1897 #endif
1898 reset_control_assert(cdns_uart_data->rstc);
1899
1900 if (!--instances)
1901 uart_unregister_driver(cdns_uart_data->cdns_uart_driver);
1902 }
1903
1904 static struct platform_driver cdns_uart_platform_driver = {
1905 .probe = cdns_uart_probe,
1906 .remove = cdns_uart_remove,
1907 .driver = {
1908 .name = CDNS_UART_NAME,
1909 .of_match_table = cdns_uart_of_match,
1910 .pm = &cdns_uart_dev_pm_ops,
1911 .suppress_bind_attrs = IS_BUILTIN(CONFIG_SERIAL_XILINX_PS_UART),
1912 },
1913 };
1914
cdns_uart_init(void)1915 static int __init cdns_uart_init(void)
1916 {
1917 /* Register the platform driver */
1918 return platform_driver_register(&cdns_uart_platform_driver);
1919 }
1920
cdns_uart_exit(void)1921 static void __exit cdns_uart_exit(void)
1922 {
1923 /* Unregister the platform driver */
1924 platform_driver_unregister(&cdns_uart_platform_driver);
1925 }
1926
1927 arch_initcall(cdns_uart_init);
1928 module_exit(cdns_uart_exit);
1929
1930 MODULE_DESCRIPTION("Driver for Cadence UART");
1931 MODULE_AUTHOR("Xilinx Inc.");
1932 MODULE_LICENSE("GPL");
1933