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  */
cdns_uart_handle_rx(void * dev_id,unsigned int isrstatus)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  */
cdns_uart_handle_tx(void * dev_id)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  */
cdns_uart_isr(int irq,void * dev_id)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  */
cdns_uart_calc_baud_divs(unsigned int clk,unsigned int baud,u32 * rbdiv,u32 * rcd,int * div8)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  */
cdns_uart_set_baud_rate(struct uart_port * port,unsigned int baud)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  */
cdns_uart_clk_notifier_cb(struct notifier_block * nb,unsigned long event,void * data)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  */
cdns_uart_start_tx(struct uart_port * port)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  */
cdns_uart_stop_tx(struct uart_port * port)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  */
cdns_uart_stop_rx(struct uart_port * port)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  */
cdns_uart_tx_empty(struct uart_port * port)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  */
cdns_uart_break_ctl(struct uart_port * port,int ctl)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  */
cdns_uart_set_termios(struct uart_port * port,struct ktermios * termios,const struct ktermios * old)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  */
cdns_uart_startup(struct uart_port * port)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  */
cdns_uart_shutdown(struct uart_port * port)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  */
cdns_uart_type(struct uart_port * port)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  */
cdns_uart_verify_port(struct uart_port * port,struct serial_struct * ser)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  */
cdns_uart_request_port(struct uart_port * port)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  */
cdns_uart_release_port(struct uart_port * port)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  */
cdns_uart_config_port(struct uart_port * port,int flags)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  */
cdns_uart_get_mctrl(struct uart_port * port)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 
cdns_uart_set_mctrl(struct uart_port * port,unsigned int mctrl)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
cdns_uart_poll_get_char(struct uart_port * port)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 
cdns_uart_poll_put_char(struct uart_port * port,unsigned char c)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 
cdns_uart_pm(struct uart_port * port,unsigned int state,unsigned int oldstate)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  */
cdns_uart_console_putchar(struct uart_port * port,unsigned char ch)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 
cdns_early_write(struct console * con,const char * s,unsigned int n)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 
cdns_early_console_setup(struct earlycon_device * device,const char * opt)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  */
cdns_uart_console_write(struct console * co,const char * s,unsigned int count)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  */
cdns_uart_console_setup(struct console * co,char * options)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  */
cdns_uart_suspend(struct device * device)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  */
cdns_uart_resume(struct device * device)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 */
cdns_runtime_suspend(struct device * dev)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 
cdns_runtime_resume(struct device * dev)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  */
cdns_uart_probe(struct platform_device * pdev)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 = irq;
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  */
cdns_uart_remove(struct platform_device * pdev)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 
1674 	/* Remove the cdns_uart port from the serial core */
1675 #ifdef CONFIG_COMMON_CLK
1676 	clk_notifier_unregister(cdns_uart_data->uartclk,
1677 			&cdns_uart_data->clk_rate_change_nb);
1678 #endif
1679 	uart_remove_one_port(cdns_uart_data->cdns_uart_driver, port);
1680 	port->mapbase = 0;
1681 	clk_disable_unprepare(cdns_uart_data->uartclk);
1682 	clk_disable_unprepare(cdns_uart_data->pclk);
1683 	pm_runtime_disable(&pdev->dev);
1684 	pm_runtime_set_suspended(&pdev->dev);
1685 	pm_runtime_dont_use_autosuspend(&pdev->dev);
1686 	device_init_wakeup(&pdev->dev, false);
1687 
1688 #ifdef CONFIG_SERIAL_XILINX_PS_UART_CONSOLE
1689 	if (console_port == port)
1690 		console_port = NULL;
1691 #endif
1692 
1693 	if (!--instances)
1694 		uart_unregister_driver(cdns_uart_data->cdns_uart_driver);
1695 	return 0;
1696 }
1697 
1698 static struct platform_driver cdns_uart_platform_driver = {
1699 	.probe   = cdns_uart_probe,
1700 	.remove  = cdns_uart_remove,
1701 	.driver  = {
1702 		.name = CDNS_UART_NAME,
1703 		.of_match_table = cdns_uart_of_match,
1704 		.pm = &cdns_uart_dev_pm_ops,
1705 		.suppress_bind_attrs = IS_BUILTIN(CONFIG_SERIAL_XILINX_PS_UART),
1706 		},
1707 };
1708 
cdns_uart_init(void)1709 static int __init cdns_uart_init(void)
1710 {
1711 	/* Register the platform driver */
1712 	return platform_driver_register(&cdns_uart_platform_driver);
1713 }
1714 
cdns_uart_exit(void)1715 static void __exit cdns_uart_exit(void)
1716 {
1717 	/* Unregister the platform driver */
1718 	platform_driver_unregister(&cdns_uart_platform_driver);
1719 }
1720 
1721 arch_initcall(cdns_uart_init);
1722 module_exit(cdns_uart_exit);
1723 
1724 MODULE_DESCRIPTION("Driver for Cadence UART");
1725 MODULE_AUTHOR("Xilinx Inc.");
1726 MODULE_LICENSE("GPL");
1727