Version:  2.0.40 2.2.26 2.4.37 3.11 3.12 3.13 3.14 3.15 3.16 3.17 3.18 3.19 4.0 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8

Linux/drivers/tty/serial/xilinx_uartps.c

  1 /*
  2  * Cadence UART driver (found in Xilinx Zynq)
  3  *
  4  * 2011 - 2014 (C) Xilinx Inc.
  5  *
  6  * This program is free software; you can redistribute it
  7  * and/or modify it under the terms of the GNU General Public
  8  * License as published by the Free Software Foundation;
  9  * either version 2 of the License, or (at your option) any
 10  * later version.
 11  *
 12  * This driver has originally been pushed by Xilinx using a Zynq-branding. This
 13  * still shows in the naming of this file, the kconfig symbols and some symbols
 14  * in the code.
 15  */
 16 
 17 #if defined(CONFIG_SERIAL_XILINX_PS_UART_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
 18 #define SUPPORT_SYSRQ
 19 #endif
 20 
 21 #include <linux/platform_device.h>
 22 #include <linux/serial.h>
 23 #include <linux/console.h>
 24 #include <linux/serial_core.h>
 25 #include <linux/slab.h>
 26 #include <linux/tty.h>
 27 #include <linux/tty_flip.h>
 28 #include <linux/clk.h>
 29 #include <linux/irq.h>
 30 #include <linux/io.h>
 31 #include <linux/of.h>
 32 #include <linux/module.h>
 33 
 34 #define CDNS_UART_TTY_NAME      "ttyPS"
 35 #define CDNS_UART_NAME          "xuartps"
 36 #define CDNS_UART_MAJOR         0       /* use dynamic node allocation */
 37 #define CDNS_UART_MINOR         0       /* works best with devtmpfs */
 38 #define CDNS_UART_NR_PORTS      2
 39 #define CDNS_UART_FIFO_SIZE     64      /* FIFO size */
 40 #define CDNS_UART_REGISTER_SPACE        0x1000
 41 
 42 /* Rx Trigger level */
 43 static int rx_trigger_level = 56;
 44 module_param(rx_trigger_level, uint, S_IRUGO);
 45 MODULE_PARM_DESC(rx_trigger_level, "Rx trigger level, 1-63 bytes");
 46 
 47 /* Rx Timeout */
 48 static int rx_timeout = 10;
 49 module_param(rx_timeout, uint, S_IRUGO);
 50 MODULE_PARM_DESC(rx_timeout, "Rx timeout, 1-255");
 51 
 52 /* Register offsets for the UART. */
 53 #define CDNS_UART_CR            0x00  /* Control Register */
 54 #define CDNS_UART_MR            0x04  /* Mode Register */
 55 #define CDNS_UART_IER           0x08  /* Interrupt Enable */
 56 #define CDNS_UART_IDR           0x0C  /* Interrupt Disable */
 57 #define CDNS_UART_IMR           0x10  /* Interrupt Mask */
 58 #define CDNS_UART_ISR           0x14  /* Interrupt Status */
 59 #define CDNS_UART_BAUDGEN       0x18  /* Baud Rate Generator */
 60 #define CDNS_UART_RXTOUT                0x1C  /* RX Timeout */
 61 #define CDNS_UART_RXWM          0x20  /* RX FIFO Trigger Level */
 62 #define CDNS_UART_MODEMCR       0x24  /* Modem Control */
 63 #define CDNS_UART_MODEMSR       0x28  /* Modem Status */
 64 #define CDNS_UART_SR            0x2C  /* Channel Status */
 65 #define CDNS_UART_FIFO          0x30  /* FIFO */
 66 #define CDNS_UART_BAUDDIV       0x34  /* Baud Rate Divider */
 67 #define CDNS_UART_FLOWDEL       0x38  /* Flow Delay */
 68 #define CDNS_UART_IRRX_PWIDTH   0x3C  /* IR Min Received Pulse Width */
 69 #define CDNS_UART_IRTX_PWIDTH   0x40  /* IR Transmitted pulse Width */
 70 #define CDNS_UART_TXWM          0x44  /* TX FIFO Trigger Level */
 71 
 72 /* Control Register Bit Definitions */
 73 #define CDNS_UART_CR_STOPBRK    0x00000100  /* Stop TX break */
 74 #define CDNS_UART_CR_STARTBRK   0x00000080  /* Set TX break */
 75 #define CDNS_UART_CR_TX_DIS     0x00000020  /* TX disabled. */
 76 #define CDNS_UART_CR_TX_EN      0x00000010  /* TX enabled */
 77 #define CDNS_UART_CR_RX_DIS     0x00000008  /* RX disabled. */
 78 #define CDNS_UART_CR_RX_EN      0x00000004  /* RX enabled */
 79 #define CDNS_UART_CR_TXRST      0x00000002  /* TX logic reset */
 80 #define CDNS_UART_CR_RXRST      0x00000001  /* RX logic reset */
 81 #define CDNS_UART_CR_RST_TO     0x00000040  /* Restart Timeout Counter */
 82 
 83 /*
 84  * Mode Register:
 85  * The mode register (MR) defines the mode of transfer as well as the data
 86  * format. If this register is modified during transmission or reception,
 87  * data validity cannot be guaranteed.
 88  */
 89 #define CDNS_UART_MR_CLKSEL             0x00000001  /* Pre-scalar selection */
 90 #define CDNS_UART_MR_CHMODE_L_LOOP      0x00000200  /* Local loop back mode */
 91 #define CDNS_UART_MR_CHMODE_NORM        0x00000000  /* Normal mode */
 92 
 93 #define CDNS_UART_MR_STOPMODE_2_BIT     0x00000080  /* 2 stop bits */
 94 #define CDNS_UART_MR_STOPMODE_1_BIT     0x00000000  /* 1 stop bit */
 95 
 96 #define CDNS_UART_MR_PARITY_NONE        0x00000020  /* No parity mode */
 97 #define CDNS_UART_MR_PARITY_MARK        0x00000018  /* Mark parity mode */
 98 #define CDNS_UART_MR_PARITY_SPACE       0x00000010  /* Space parity mode */
 99 #define CDNS_UART_MR_PARITY_ODD         0x00000008  /* Odd parity mode */
100 #define CDNS_UART_MR_PARITY_EVEN        0x00000000  /* Even parity mode */
101 
102 #define CDNS_UART_MR_CHARLEN_6_BIT      0x00000006  /* 6 bits data */
103 #define CDNS_UART_MR_CHARLEN_7_BIT      0x00000004  /* 7 bits data */
104 #define CDNS_UART_MR_CHARLEN_8_BIT      0x00000000  /* 8 bits data */
105 
106 /*
107  * Interrupt Registers:
108  * Interrupt control logic uses the interrupt enable register (IER) and the
109  * interrupt disable register (IDR) to set the value of the bits in the
110  * interrupt mask register (IMR). The IMR determines whether to pass an
111  * interrupt to the interrupt status register (ISR).
112  * Writing a 1 to IER Enables an interrupt, writing a 1 to IDR disables an
113  * interrupt. IMR and ISR are read only, and IER and IDR are write only.
114  * Reading either IER or IDR returns 0x00.
115  * All four registers have the same bit definitions.
116  */
117 #define CDNS_UART_IXR_TOUT      0x00000100 /* RX Timeout error interrupt */
118 #define CDNS_UART_IXR_PARITY    0x00000080 /* Parity error interrupt */
119 #define CDNS_UART_IXR_FRAMING   0x00000040 /* Framing error interrupt */
120 #define CDNS_UART_IXR_OVERRUN   0x00000020 /* Overrun error interrupt */
121 #define CDNS_UART_IXR_TXFULL    0x00000010 /* TX FIFO Full interrupt */
122 #define CDNS_UART_IXR_TXEMPTY   0x00000008 /* TX FIFO empty interrupt */
123 #define CDNS_UART_ISR_RXEMPTY   0x00000002 /* RX FIFO empty interrupt */
124 #define CDNS_UART_IXR_RXTRIG    0x00000001 /* RX FIFO trigger interrupt */
125 #define CDNS_UART_IXR_RXFULL    0x00000004 /* RX FIFO full interrupt. */
126 #define CDNS_UART_IXR_RXEMPTY   0x00000002 /* RX FIFO empty interrupt. */
127 #define CDNS_UART_IXR_MASK      0x00001FFF /* Valid bit mask */
128 
129 #define CDNS_UART_RX_IRQS       (CDNS_UART_IXR_PARITY | CDNS_UART_IXR_FRAMING | \
130                                  CDNS_UART_IXR_OVERRUN | CDNS_UART_IXR_RXTRIG | \
131                                  CDNS_UART_IXR_TOUT)
132 
133 /* Goes in read_status_mask for break detection as the HW doesn't do it*/
134 #define CDNS_UART_IXR_BRK       0x80000000
135 
136 /*
137  * Modem Control register:
138  * The read/write Modem Control register controls the interface with the modem
139  * or data set, or a peripheral device emulating a modem.
140  */
141 #define CDNS_UART_MODEMCR_FCM   0x00000020 /* Automatic flow control mode */
142 #define CDNS_UART_MODEMCR_RTS   0x00000002 /* Request to send output control */
143 #define CDNS_UART_MODEMCR_DTR   0x00000001 /* Data Terminal Ready */
144 
145 /*
146  * Channel Status Register:
147  * The channel status register (CSR) is provided to enable the control logic
148  * to monitor the status of bits in the channel interrupt status register,
149  * even if these are masked out by the interrupt mask register.
150  */
151 #define CDNS_UART_SR_RXEMPTY    0x00000002 /* RX FIFO empty */
152 #define CDNS_UART_SR_TXEMPTY    0x00000008 /* TX FIFO empty */
153 #define CDNS_UART_SR_TXFULL     0x00000010 /* TX FIFO full */
154 #define CDNS_UART_SR_RXTRIG     0x00000001 /* Rx Trigger */
155 
156 /* baud dividers min/max values */
157 #define CDNS_UART_BDIV_MIN      4
158 #define CDNS_UART_BDIV_MAX      255
159 #define CDNS_UART_CD_MAX        65535
160 
161 /**
162  * struct cdns_uart - device data
163  * @port:               Pointer to the UART port
164  * @uartclk:            Reference clock
165  * @pclk:               APB clock
166  * @baud:               Current baud rate
167  * @clk_rate_change_nb: Notifier block for clock changes
168  */
169 struct cdns_uart {
170         struct uart_port        *port;
171         struct clk              *uartclk;
172         struct clk              *pclk;
173         unsigned int            baud;
174         struct notifier_block   clk_rate_change_nb;
175 };
176 #define to_cdns_uart(_nb) container_of(_nb, struct cdns_uart, \
177                 clk_rate_change_nb);
178 
179 static void cdns_uart_handle_rx(struct uart_port *port, unsigned int isrstatus)
180 {
181         /*
182          * There is no hardware break detection, so we interpret framing
183          * error with all-zeros data as a break sequence. Most of the time,
184          * there's another non-zero byte at the end of the sequence.
185          */
186         if (isrstatus & CDNS_UART_IXR_FRAMING) {
187                 while (!(readl(port->membase + CDNS_UART_SR) &
188                                         CDNS_UART_SR_RXEMPTY)) {
189                         if (!readl(port->membase + CDNS_UART_FIFO)) {
190                                 port->read_status_mask |= CDNS_UART_IXR_BRK;
191                                 isrstatus &= ~CDNS_UART_IXR_FRAMING;
192                         }
193                 }
194                 writel(CDNS_UART_IXR_FRAMING, port->membase + CDNS_UART_ISR);
195         }
196 
197         /* drop byte with parity error if IGNPAR specified */
198         if (isrstatus & port->ignore_status_mask & CDNS_UART_IXR_PARITY)
199                 isrstatus &= ~(CDNS_UART_IXR_RXTRIG | CDNS_UART_IXR_TOUT);
200 
201         isrstatus &= port->read_status_mask;
202         isrstatus &= ~port->ignore_status_mask;
203 
204         if (!(isrstatus & (CDNS_UART_IXR_TOUT | CDNS_UART_IXR_RXTRIG)))
205                 return;
206 
207         while (!(readl(port->membase + CDNS_UART_SR) & CDNS_UART_SR_RXEMPTY)) {
208                 u32 data;
209                 char status = TTY_NORMAL;
210 
211                 data = readl(port->membase + CDNS_UART_FIFO);
212 
213                 /* Non-NULL byte after BREAK is garbage (99%) */
214                 if (data && (port->read_status_mask & CDNS_UART_IXR_BRK)) {
215                         port->read_status_mask &= ~CDNS_UART_IXR_BRK;
216                         port->icount.brk++;
217                         if (uart_handle_break(port))
218                                 continue;
219                 }
220 
221                 if (uart_handle_sysrq_char(port, data))
222                         continue;
223 
224                 port->icount.rx++;
225 
226                 if (isrstatus & CDNS_UART_IXR_PARITY) {
227                         port->icount.parity++;
228                         status = TTY_PARITY;
229                 } else if (isrstatus & CDNS_UART_IXR_FRAMING) {
230                         port->icount.frame++;
231                         status = TTY_FRAME;
232                 } else if (isrstatus & CDNS_UART_IXR_OVERRUN) {
233                         port->icount.overrun++;
234                 }
235 
236                 uart_insert_char(port, isrstatus, CDNS_UART_IXR_OVERRUN,
237                                  data, status);
238         }
239         tty_flip_buffer_push(&port->state->port);
240 }
241 
242 static void cdns_uart_handle_tx(struct uart_port *port)
243 {
244         unsigned int numbytes;
245 
246         if (uart_circ_empty(&port->state->xmit)) {
247                 writel(CDNS_UART_IXR_TXEMPTY, port->membase + CDNS_UART_IDR);
248                 return;
249         }
250 
251         numbytes = port->fifosize;
252         while (numbytes && !uart_circ_empty(&port->state->xmit) &&
253                !(readl(port->membase + CDNS_UART_SR) & CDNS_UART_SR_TXFULL)) {
254                 /*
255                  * Get the data from the UART circular buffer
256                  * and write it to the cdns_uart's TX_FIFO
257                  * register.
258                  */
259                 writel(port->state->xmit.buf[port->state->xmit.tail],
260                         port->membase + CDNS_UART_FIFO);
261                 port->icount.tx++;
262 
263                 /*
264                  * Adjust the tail of the UART buffer and wrap
265                  * the buffer if it reaches limit.
266                  */
267                 port->state->xmit.tail =
268                         (port->state->xmit.tail + 1) & (UART_XMIT_SIZE - 1);
269 
270                 numbytes--;
271         }
272 
273         if (uart_circ_chars_pending(&port->state->xmit) < WAKEUP_CHARS)
274                 uart_write_wakeup(port);
275 }
276 
277 /**
278  * cdns_uart_isr - Interrupt handler
279  * @irq: Irq number
280  * @dev_id: Id of the port
281  *
282  * Return: IRQHANDLED
283  */
284 static irqreturn_t cdns_uart_isr(int irq, void *dev_id)
285 {
286         struct uart_port *port = (struct uart_port *)dev_id;
287         unsigned long flags;
288         unsigned int isrstatus;
289 
290         spin_lock_irqsave(&port->lock, flags);
291 
292         /* Read the interrupt status register to determine which
293          * interrupt(s) is/are active.
294          */
295         isrstatus = readl(port->membase + CDNS_UART_ISR);
296 
297         if (isrstatus & CDNS_UART_RX_IRQS)
298                 cdns_uart_handle_rx(port, isrstatus);
299 
300         if ((isrstatus & CDNS_UART_IXR_TXEMPTY) == CDNS_UART_IXR_TXEMPTY)
301                 cdns_uart_handle_tx(port);
302 
303         writel(isrstatus, port->membase + CDNS_UART_ISR);
304 
305         /* be sure to release the lock and tty before leaving */
306         spin_unlock_irqrestore(&port->lock, flags);
307 
308         return IRQ_HANDLED;
309 }
310 
311 /**
312  * cdns_uart_calc_baud_divs - Calculate baud rate divisors
313  * @clk: UART module input clock
314  * @baud: Desired baud rate
315  * @rbdiv: BDIV value (return value)
316  * @rcd: CD value (return value)
317  * @div8: Value for clk_sel bit in mod (return value)
318  * Return: baud rate, requested baud when possible, or actual baud when there
319  *      was too much error, zero if no valid divisors are found.
320  *
321  * Formula to obtain baud rate is
322  *      baud_tx/rx rate = clk/CD * (BDIV + 1)
323  *      input_clk = (Uart User Defined Clock or Apb Clock)
324  *              depends on UCLKEN in MR Reg
325  *      clk = input_clk or input_clk/8;
326  *              depends on CLKS in MR reg
327  *      CD and BDIV depends on values in
328  *                      baud rate generate register
329  *                      baud rate clock divisor register
330  */
331 static unsigned int cdns_uart_calc_baud_divs(unsigned int clk,
332                 unsigned int baud, u32 *rbdiv, u32 *rcd, int *div8)
333 {
334         u32 cd, bdiv;
335         unsigned int calc_baud;
336         unsigned int bestbaud = 0;
337         unsigned int bauderror;
338         unsigned int besterror = ~0;
339 
340         if (baud < clk / ((CDNS_UART_BDIV_MAX + 1) * CDNS_UART_CD_MAX)) {
341                 *div8 = 1;
342                 clk /= 8;
343         } else {
344                 *div8 = 0;
345         }
346 
347         for (bdiv = CDNS_UART_BDIV_MIN; bdiv <= CDNS_UART_BDIV_MAX; bdiv++) {
348                 cd = DIV_ROUND_CLOSEST(clk, baud * (bdiv + 1));
349                 if (cd < 1 || cd > CDNS_UART_CD_MAX)
350                         continue;
351 
352                 calc_baud = clk / (cd * (bdiv + 1));
353 
354                 if (baud > calc_baud)
355                         bauderror = baud - calc_baud;
356                 else
357                         bauderror = calc_baud - baud;
358 
359                 if (besterror > bauderror) {
360                         *rbdiv = bdiv;
361                         *rcd = cd;
362                         bestbaud = calc_baud;
363                         besterror = bauderror;
364                 }
365         }
366         /* use the values when percent error is acceptable */
367         if (((besterror * 100) / baud) < 3)
368                 bestbaud = baud;
369 
370         return bestbaud;
371 }
372 
373 /**
374  * cdns_uart_set_baud_rate - Calculate and set the baud rate
375  * @port: Handle to the uart port structure
376  * @baud: Baud rate to set
377  * Return: baud rate, requested baud when possible, or actual baud when there
378  *         was too much error, zero if no valid divisors are found.
379  */
380 static unsigned int cdns_uart_set_baud_rate(struct uart_port *port,
381                 unsigned int baud)
382 {
383         unsigned int calc_baud;
384         u32 cd = 0, bdiv = 0;
385         u32 mreg;
386         int div8;
387         struct cdns_uart *cdns_uart = port->private_data;
388 
389         calc_baud = cdns_uart_calc_baud_divs(port->uartclk, baud, &bdiv, &cd,
390                         &div8);
391 
392         /* Write new divisors to hardware */
393         mreg = readl(port->membase + CDNS_UART_MR);
394         if (div8)
395                 mreg |= CDNS_UART_MR_CLKSEL;
396         else
397                 mreg &= ~CDNS_UART_MR_CLKSEL;
398         writel(mreg, port->membase + CDNS_UART_MR);
399         writel(cd, port->membase + CDNS_UART_BAUDGEN);
400         writel(bdiv, port->membase + CDNS_UART_BAUDDIV);
401         cdns_uart->baud = baud;
402 
403         return calc_baud;
404 }
405 
406 #ifdef CONFIG_COMMON_CLK
407 /**
408  * cdns_uart_clk_notitifer_cb - Clock notifier callback
409  * @nb:         Notifier block
410  * @event:      Notify event
411  * @data:       Notifier data
412  * Return:      NOTIFY_OK or NOTIFY_DONE on success, NOTIFY_BAD on error.
413  */
414 static int cdns_uart_clk_notifier_cb(struct notifier_block *nb,
415                 unsigned long event, void *data)
416 {
417         u32 ctrl_reg;
418         struct uart_port *port;
419         int locked = 0;
420         struct clk_notifier_data *ndata = data;
421         unsigned long flags = 0;
422         struct cdns_uart *cdns_uart = to_cdns_uart(nb);
423 
424         port = cdns_uart->port;
425         if (port->suspended)
426                 return NOTIFY_OK;
427 
428         switch (event) {
429         case PRE_RATE_CHANGE:
430         {
431                 u32 bdiv, cd;
432                 int div8;
433 
434                 /*
435                  * Find out if current baud-rate can be achieved with new clock
436                  * frequency.
437                  */
438                 if (!cdns_uart_calc_baud_divs(ndata->new_rate, cdns_uart->baud,
439                                         &bdiv, &cd, &div8)) {
440                         dev_warn(port->dev, "clock rate change rejected\n");
441                         return NOTIFY_BAD;
442                 }
443 
444                 spin_lock_irqsave(&cdns_uart->port->lock, flags);
445 
446                 /* Disable the TX and RX to set baud rate */
447                 ctrl_reg = readl(port->membase + CDNS_UART_CR);
448                 ctrl_reg |= CDNS_UART_CR_TX_DIS | CDNS_UART_CR_RX_DIS;
449                 writel(ctrl_reg, port->membase + CDNS_UART_CR);
450 
451                 spin_unlock_irqrestore(&cdns_uart->port->lock, flags);
452 
453                 return NOTIFY_OK;
454         }
455         case POST_RATE_CHANGE:
456                 /*
457                  * Set clk dividers to generate correct baud with new clock
458                  * frequency.
459                  */
460 
461                 spin_lock_irqsave(&cdns_uart->port->lock, flags);
462 
463                 locked = 1;
464                 port->uartclk = ndata->new_rate;
465 
466                 cdns_uart->baud = cdns_uart_set_baud_rate(cdns_uart->port,
467                                 cdns_uart->baud);
468                 /* fall through */
469         case ABORT_RATE_CHANGE:
470                 if (!locked)
471                         spin_lock_irqsave(&cdns_uart->port->lock, flags);
472 
473                 /* Set TX/RX Reset */
474                 ctrl_reg = readl(port->membase + CDNS_UART_CR);
475                 ctrl_reg |= CDNS_UART_CR_TXRST | CDNS_UART_CR_RXRST;
476                 writel(ctrl_reg, port->membase + CDNS_UART_CR);
477 
478                 while (readl(port->membase + CDNS_UART_CR) &
479                                 (CDNS_UART_CR_TXRST | CDNS_UART_CR_RXRST))
480                         cpu_relax();
481 
482                 /*
483                  * Clear the RX disable and TX disable bits and then set the TX
484                  * enable bit and RX enable bit to enable the transmitter and
485                  * receiver.
486                  */
487                 writel(rx_timeout, port->membase + CDNS_UART_RXTOUT);
488                 ctrl_reg = readl(port->membase + CDNS_UART_CR);
489                 ctrl_reg &= ~(CDNS_UART_CR_TX_DIS | CDNS_UART_CR_RX_DIS);
490                 ctrl_reg |= CDNS_UART_CR_TX_EN | CDNS_UART_CR_RX_EN;
491                 writel(ctrl_reg, port->membase + CDNS_UART_CR);
492 
493                 spin_unlock_irqrestore(&cdns_uart->port->lock, flags);
494 
495                 return NOTIFY_OK;
496         default:
497                 return NOTIFY_DONE;
498         }
499 }
500 #endif
501 
502 /**
503  * cdns_uart_start_tx -  Start transmitting bytes
504  * @port: Handle to the uart port structure
505  */
506 static void cdns_uart_start_tx(struct uart_port *port)
507 {
508         unsigned int status;
509 
510         if (uart_tx_stopped(port))
511                 return;
512 
513         /*
514          * Set the TX enable bit and clear the TX disable bit to enable the
515          * transmitter.
516          */
517         status = readl(port->membase + CDNS_UART_CR);
518         status &= ~CDNS_UART_CR_TX_DIS;
519         status |= CDNS_UART_CR_TX_EN;
520         writel(status, port->membase + CDNS_UART_CR);
521 
522         if (uart_circ_empty(&port->state->xmit))
523                 return;
524 
525         cdns_uart_handle_tx(port);
526 
527         writel(CDNS_UART_IXR_TXEMPTY, port->membase + CDNS_UART_ISR);
528         /* Enable the TX Empty interrupt */
529         writel(CDNS_UART_IXR_TXEMPTY, port->membase + CDNS_UART_IER);
530 }
531 
532 /**
533  * cdns_uart_stop_tx - Stop TX
534  * @port: Handle to the uart port structure
535  */
536 static void cdns_uart_stop_tx(struct uart_port *port)
537 {
538         unsigned int regval;
539 
540         regval = readl(port->membase + CDNS_UART_CR);
541         regval |= CDNS_UART_CR_TX_DIS;
542         /* Disable the transmitter */
543         writel(regval, port->membase + CDNS_UART_CR);
544 }
545 
546 /**
547  * cdns_uart_stop_rx - Stop RX
548  * @port: Handle to the uart port structure
549  */
550 static void cdns_uart_stop_rx(struct uart_port *port)
551 {
552         unsigned int regval;
553 
554         /* Disable RX IRQs */
555         writel(CDNS_UART_RX_IRQS, port->membase + CDNS_UART_IDR);
556 
557         /* Disable the receiver */
558         regval = readl(port->membase + CDNS_UART_CR);
559         regval |= CDNS_UART_CR_RX_DIS;
560         writel(regval, port->membase + CDNS_UART_CR);
561 }
562 
563 /**
564  * cdns_uart_tx_empty -  Check whether TX is empty
565  * @port: Handle to the uart port structure
566  *
567  * Return: TIOCSER_TEMT on success, 0 otherwise
568  */
569 static unsigned int cdns_uart_tx_empty(struct uart_port *port)
570 {
571         unsigned int status;
572 
573         status = readl(port->membase + CDNS_UART_SR) &
574                                 CDNS_UART_SR_TXEMPTY;
575         return status ? TIOCSER_TEMT : 0;
576 }
577 
578 /**
579  * cdns_uart_break_ctl - Based on the input ctl we have to start or stop
580  *                      transmitting char breaks
581  * @port: Handle to the uart port structure
582  * @ctl: Value based on which start or stop decision is taken
583  */
584 static void cdns_uart_break_ctl(struct uart_port *port, int ctl)
585 {
586         unsigned int status;
587         unsigned long flags;
588 
589         spin_lock_irqsave(&port->lock, flags);
590 
591         status = readl(port->membase + CDNS_UART_CR);
592 
593         if (ctl == -1)
594                 writel(CDNS_UART_CR_STARTBRK | status,
595                                 port->membase + CDNS_UART_CR);
596         else {
597                 if ((status & CDNS_UART_CR_STOPBRK) == 0)
598                         writel(CDNS_UART_CR_STOPBRK | status,
599                                         port->membase + CDNS_UART_CR);
600         }
601         spin_unlock_irqrestore(&port->lock, flags);
602 }
603 
604 /**
605  * cdns_uart_set_termios - termios operations, handling data length, parity,
606  *                              stop bits, flow control, baud rate
607  * @port: Handle to the uart port structure
608  * @termios: Handle to the input termios structure
609  * @old: Values of the previously saved termios structure
610  */
611 static void cdns_uart_set_termios(struct uart_port *port,
612                                 struct ktermios *termios, struct ktermios *old)
613 {
614         unsigned int cval = 0;
615         unsigned int baud, minbaud, maxbaud;
616         unsigned long flags;
617         unsigned int ctrl_reg, mode_reg;
618 
619         spin_lock_irqsave(&port->lock, flags);
620 
621         /* Wait for the transmit FIFO to empty before making changes */
622         if (!(readl(port->membase + CDNS_UART_CR) &
623                                 CDNS_UART_CR_TX_DIS)) {
624                 while (!(readl(port->membase + CDNS_UART_SR) &
625                                 CDNS_UART_SR_TXEMPTY)) {
626                         cpu_relax();
627                 }
628         }
629 
630         /* Disable the TX and RX to set baud rate */
631         ctrl_reg = readl(port->membase + CDNS_UART_CR);
632         ctrl_reg |= CDNS_UART_CR_TX_DIS | CDNS_UART_CR_RX_DIS;
633         writel(ctrl_reg, port->membase + CDNS_UART_CR);
634 
635         /*
636          * Min baud rate = 6bps and Max Baud Rate is 10Mbps for 100Mhz clk
637          * min and max baud should be calculated here based on port->uartclk.
638          * this way we get a valid baud and can safely call set_baud()
639          */
640         minbaud = port->uartclk /
641                         ((CDNS_UART_BDIV_MAX + 1) * CDNS_UART_CD_MAX * 8);
642         maxbaud = port->uartclk / (CDNS_UART_BDIV_MIN + 1);
643         baud = uart_get_baud_rate(port, termios, old, minbaud, maxbaud);
644         baud = cdns_uart_set_baud_rate(port, baud);
645         if (tty_termios_baud_rate(termios))
646                 tty_termios_encode_baud_rate(termios, baud, baud);
647 
648         /* Update the per-port timeout. */
649         uart_update_timeout(port, termios->c_cflag, baud);
650 
651         /* Set TX/RX Reset */
652         ctrl_reg = readl(port->membase + CDNS_UART_CR);
653         ctrl_reg |= CDNS_UART_CR_TXRST | CDNS_UART_CR_RXRST;
654         writel(ctrl_reg, port->membase + CDNS_UART_CR);
655 
656         /*
657          * Clear the RX disable and TX disable bits and then set the TX enable
658          * bit and RX enable bit to enable the transmitter and receiver.
659          */
660         ctrl_reg = readl(port->membase + CDNS_UART_CR);
661         ctrl_reg &= ~(CDNS_UART_CR_TX_DIS | CDNS_UART_CR_RX_DIS);
662         ctrl_reg |= CDNS_UART_CR_TX_EN | CDNS_UART_CR_RX_EN;
663         writel(ctrl_reg, port->membase + CDNS_UART_CR);
664 
665         writel(rx_timeout, port->membase + CDNS_UART_RXTOUT);
666 
667         port->read_status_mask = CDNS_UART_IXR_TXEMPTY | CDNS_UART_IXR_RXTRIG |
668                         CDNS_UART_IXR_OVERRUN | CDNS_UART_IXR_TOUT;
669         port->ignore_status_mask = 0;
670 
671         if (termios->c_iflag & INPCK)
672                 port->read_status_mask |= CDNS_UART_IXR_PARITY |
673                 CDNS_UART_IXR_FRAMING;
674 
675         if (termios->c_iflag & IGNPAR)
676                 port->ignore_status_mask |= CDNS_UART_IXR_PARITY |
677                         CDNS_UART_IXR_FRAMING | CDNS_UART_IXR_OVERRUN;
678 
679         /* ignore all characters if CREAD is not set */
680         if ((termios->c_cflag & CREAD) == 0)
681                 port->ignore_status_mask |= CDNS_UART_IXR_RXTRIG |
682                         CDNS_UART_IXR_TOUT | CDNS_UART_IXR_PARITY |
683                         CDNS_UART_IXR_FRAMING | CDNS_UART_IXR_OVERRUN;
684 
685         mode_reg = readl(port->membase + CDNS_UART_MR);
686 
687         /* Handling Data Size */
688         switch (termios->c_cflag & CSIZE) {
689         case CS6:
690                 cval |= CDNS_UART_MR_CHARLEN_6_BIT;
691                 break;
692         case CS7:
693                 cval |= CDNS_UART_MR_CHARLEN_7_BIT;
694                 break;
695         default:
696         case CS8:
697                 cval |= CDNS_UART_MR_CHARLEN_8_BIT;
698                 termios->c_cflag &= ~CSIZE;
699                 termios->c_cflag |= CS8;
700                 break;
701         }
702 
703         /* Handling Parity and Stop Bits length */
704         if (termios->c_cflag & CSTOPB)
705                 cval |= CDNS_UART_MR_STOPMODE_2_BIT; /* 2 STOP bits */
706         else
707                 cval |= CDNS_UART_MR_STOPMODE_1_BIT; /* 1 STOP bit */
708 
709         if (termios->c_cflag & PARENB) {
710                 /* Mark or Space parity */
711                 if (termios->c_cflag & CMSPAR) {
712                         if (termios->c_cflag & PARODD)
713                                 cval |= CDNS_UART_MR_PARITY_MARK;
714                         else
715                                 cval |= CDNS_UART_MR_PARITY_SPACE;
716                 } else {
717                         if (termios->c_cflag & PARODD)
718                                 cval |= CDNS_UART_MR_PARITY_ODD;
719                         else
720                                 cval |= CDNS_UART_MR_PARITY_EVEN;
721                 }
722         } else {
723                 cval |= CDNS_UART_MR_PARITY_NONE;
724         }
725         cval |= mode_reg & 1;
726         writel(cval, port->membase + CDNS_UART_MR);
727 
728         spin_unlock_irqrestore(&port->lock, flags);
729 }
730 
731 /**
732  * cdns_uart_startup - Called when an application opens a cdns_uart port
733  * @port: Handle to the uart port structure
734  *
735  * Return: 0 on success, negative errno otherwise
736  */
737 static int cdns_uart_startup(struct uart_port *port)
738 {
739         int ret;
740         unsigned long flags;
741         unsigned int status = 0;
742 
743         spin_lock_irqsave(&port->lock, flags);
744 
745         /* Disable the TX and RX */
746         writel(CDNS_UART_CR_TX_DIS | CDNS_UART_CR_RX_DIS,
747                         port->membase + CDNS_UART_CR);
748 
749         /* Set the Control Register with TX/RX Enable, TX/RX Reset,
750          * no break chars.
751          */
752         writel(CDNS_UART_CR_TXRST | CDNS_UART_CR_RXRST,
753                         port->membase + CDNS_UART_CR);
754 
755         /*
756          * Clear the RX disable bit and then set the RX enable bit to enable
757          * the receiver.
758          */
759         status = readl(port->membase + CDNS_UART_CR);
760         status &= CDNS_UART_CR_RX_DIS;
761         status |= CDNS_UART_CR_RX_EN;
762         writel(status, port->membase + CDNS_UART_CR);
763 
764         /* Set the Mode Register with normal mode,8 data bits,1 stop bit,
765          * no parity.
766          */
767         writel(CDNS_UART_MR_CHMODE_NORM | CDNS_UART_MR_STOPMODE_1_BIT
768                 | CDNS_UART_MR_PARITY_NONE | CDNS_UART_MR_CHARLEN_8_BIT,
769                 port->membase + CDNS_UART_MR);
770 
771         /*
772          * Set the RX FIFO Trigger level to use most of the FIFO, but it
773          * can be tuned with a module parameter
774          */
775         writel(rx_trigger_level, port->membase + CDNS_UART_RXWM);
776 
777         /*
778          * Receive Timeout register is enabled but it
779          * can be tuned with a module parameter
780          */
781         writel(rx_timeout, port->membase + CDNS_UART_RXTOUT);
782 
783         /* Clear out any pending interrupts before enabling them */
784         writel(readl(port->membase + CDNS_UART_ISR),
785                         port->membase + CDNS_UART_ISR);
786 
787         spin_unlock_irqrestore(&port->lock, flags);
788 
789         ret = request_irq(port->irq, cdns_uart_isr, 0, CDNS_UART_NAME, port);
790         if (ret) {
791                 dev_err(port->dev, "request_irq '%d' failed with %d\n",
792                         port->irq, ret);
793                 return ret;
794         }
795 
796         /* Set the Interrupt Registers with desired interrupts */
797         writel(CDNS_UART_RX_IRQS, port->membase + CDNS_UART_IER);
798 
799         return 0;
800 }
801 
802 /**
803  * cdns_uart_shutdown - Called when an application closes a cdns_uart port
804  * @port: Handle to the uart port structure
805  */
806 static void cdns_uart_shutdown(struct uart_port *port)
807 {
808         int status;
809         unsigned long flags;
810 
811         spin_lock_irqsave(&port->lock, flags);
812 
813         /* Disable interrupts */
814         status = readl(port->membase + CDNS_UART_IMR);
815         writel(status, port->membase + CDNS_UART_IDR);
816         writel(0xffffffff, port->membase + CDNS_UART_ISR);
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         spin_unlock_irqrestore(&port->lock, flags);
823 
824         free_irq(port->irq, port);
825 }
826 
827 /**
828  * cdns_uart_type - Set UART type to cdns_uart port
829  * @port: Handle to the uart port structure
830  *
831  * Return: string on success, NULL otherwise
832  */
833 static const char *cdns_uart_type(struct uart_port *port)
834 {
835         return port->type == PORT_XUARTPS ? CDNS_UART_NAME : NULL;
836 }
837 
838 /**
839  * cdns_uart_verify_port - Verify the port params
840  * @port: Handle to the uart port structure
841  * @ser: Handle to the structure whose members are compared
842  *
843  * Return: 0 on success, negative errno otherwise.
844  */
845 static int cdns_uart_verify_port(struct uart_port *port,
846                                         struct serial_struct *ser)
847 {
848         if (ser->type != PORT_UNKNOWN && ser->type != PORT_XUARTPS)
849                 return -EINVAL;
850         if (port->irq != ser->irq)
851                 return -EINVAL;
852         if (ser->io_type != UPIO_MEM)
853                 return -EINVAL;
854         if (port->iobase != ser->port)
855                 return -EINVAL;
856         if (ser->hub6 != 0)
857                 return -EINVAL;
858         return 0;
859 }
860 
861 /**
862  * cdns_uart_request_port - Claim the memory region attached to cdns_uart port,
863  *                              called when the driver adds a cdns_uart port via
864  *                              uart_add_one_port()
865  * @port: Handle to the uart port structure
866  *
867  * Return: 0 on success, negative errno otherwise.
868  */
869 static int cdns_uart_request_port(struct uart_port *port)
870 {
871         if (!request_mem_region(port->mapbase, CDNS_UART_REGISTER_SPACE,
872                                          CDNS_UART_NAME)) {
873                 return -ENOMEM;
874         }
875 
876         port->membase = ioremap(port->mapbase, CDNS_UART_REGISTER_SPACE);
877         if (!port->membase) {
878                 dev_err(port->dev, "Unable to map registers\n");
879                 release_mem_region(port->mapbase, CDNS_UART_REGISTER_SPACE);
880                 return -ENOMEM;
881         }
882         return 0;
883 }
884 
885 /**
886  * cdns_uart_release_port - Release UART port
887  * @port: Handle to the uart port structure
888  *
889  * Release the memory region attached to a cdns_uart port. Called when the
890  * driver removes a cdns_uart port via uart_remove_one_port().
891  */
892 static void cdns_uart_release_port(struct uart_port *port)
893 {
894         release_mem_region(port->mapbase, CDNS_UART_REGISTER_SPACE);
895         iounmap(port->membase);
896         port->membase = NULL;
897 }
898 
899 /**
900  * cdns_uart_config_port - Configure UART port
901  * @port: Handle to the uart port structure
902  * @flags: If any
903  */
904 static void cdns_uart_config_port(struct uart_port *port, int flags)
905 {
906         if (flags & UART_CONFIG_TYPE && cdns_uart_request_port(port) == 0)
907                 port->type = PORT_XUARTPS;
908 }
909 
910 /**
911  * cdns_uart_get_mctrl - Get the modem control state
912  * @port: Handle to the uart port structure
913  *
914  * Return: the modem control state
915  */
916 static unsigned int cdns_uart_get_mctrl(struct uart_port *port)
917 {
918         return TIOCM_CTS | TIOCM_DSR | TIOCM_CAR;
919 }
920 
921 static void cdns_uart_set_mctrl(struct uart_port *port, unsigned int mctrl)
922 {
923         u32 val;
924 
925         val = readl(port->membase + CDNS_UART_MODEMCR);
926 
927         val &= ~(CDNS_UART_MODEMCR_RTS | CDNS_UART_MODEMCR_DTR);
928 
929         if (mctrl & TIOCM_RTS)
930                 val |= CDNS_UART_MODEMCR_RTS;
931         if (mctrl & TIOCM_DTR)
932                 val |= CDNS_UART_MODEMCR_DTR;
933 
934         writel(val, port->membase + CDNS_UART_MODEMCR);
935 }
936 
937 #ifdef CONFIG_CONSOLE_POLL
938 static int cdns_uart_poll_get_char(struct uart_port *port)
939 {
940         int c;
941         unsigned long flags;
942 
943         spin_lock_irqsave(&port->lock, flags);
944 
945         /* Check if FIFO is empty */
946         if (readl(port->membase + CDNS_UART_SR) & CDNS_UART_SR_RXEMPTY)
947                 c = NO_POLL_CHAR;
948         else /* Read a character */
949                 c = (unsigned char) readl(port->membase + CDNS_UART_FIFO);
950 
951         spin_unlock_irqrestore(&port->lock, flags);
952 
953         return c;
954 }
955 
956 static void cdns_uart_poll_put_char(struct uart_port *port, unsigned char c)
957 {
958         unsigned long flags;
959 
960         spin_lock_irqsave(&port->lock, flags);
961 
962         /* Wait until FIFO is empty */
963         while (!(readl(port->membase + CDNS_UART_SR) & CDNS_UART_SR_TXEMPTY))
964                 cpu_relax();
965 
966         /* Write a character */
967         writel(c, port->membase + CDNS_UART_FIFO);
968 
969         /* Wait until FIFO is empty */
970         while (!(readl(port->membase + CDNS_UART_SR) & CDNS_UART_SR_TXEMPTY))
971                 cpu_relax();
972 
973         spin_unlock_irqrestore(&port->lock, flags);
974 
975         return;
976 }
977 #endif
978 
979 static void cdns_uart_pm(struct uart_port *port, unsigned int state,
980                    unsigned int oldstate)
981 {
982         struct cdns_uart *cdns_uart = port->private_data;
983 
984         switch (state) {
985         case UART_PM_STATE_OFF:
986                 clk_disable(cdns_uart->uartclk);
987                 clk_disable(cdns_uart->pclk);
988                 break;
989         default:
990                 clk_enable(cdns_uart->pclk);
991                 clk_enable(cdns_uart->uartclk);
992                 break;
993         }
994 }
995 
996 static struct uart_ops cdns_uart_ops = {
997         .set_mctrl      = cdns_uart_set_mctrl,
998         .get_mctrl      = cdns_uart_get_mctrl,
999         .start_tx       = cdns_uart_start_tx,
1000         .stop_tx        = cdns_uart_stop_tx,
1001         .stop_rx        = cdns_uart_stop_rx,
1002         .tx_empty       = cdns_uart_tx_empty,
1003         .break_ctl      = cdns_uart_break_ctl,
1004         .set_termios    = cdns_uart_set_termios,
1005         .startup        = cdns_uart_startup,
1006         .shutdown       = cdns_uart_shutdown,
1007         .pm             = cdns_uart_pm,
1008         .type           = cdns_uart_type,
1009         .verify_port    = cdns_uart_verify_port,
1010         .request_port   = cdns_uart_request_port,
1011         .release_port   = cdns_uart_release_port,
1012         .config_port    = cdns_uart_config_port,
1013 #ifdef CONFIG_CONSOLE_POLL
1014         .poll_get_char  = cdns_uart_poll_get_char,
1015         .poll_put_char  = cdns_uart_poll_put_char,
1016 #endif
1017 };
1018 
1019 static struct uart_port cdns_uart_port[CDNS_UART_NR_PORTS];
1020 
1021 /**
1022  * cdns_uart_get_port - Configure the port from platform device resource info
1023  * @id: Port id
1024  *
1025  * Return: a pointer to a uart_port or NULL for failure
1026  */
1027 static struct uart_port *cdns_uart_get_port(int id)
1028 {
1029         struct uart_port *port;
1030 
1031         /* Try the given port id if failed use default method */
1032         if (cdns_uart_port[id].mapbase != 0) {
1033                 /* Find the next unused port */
1034                 for (id = 0; id < CDNS_UART_NR_PORTS; id++)
1035                         if (cdns_uart_port[id].mapbase == 0)
1036                                 break;
1037         }
1038 
1039         if (id >= CDNS_UART_NR_PORTS)
1040                 return NULL;
1041 
1042         port = &cdns_uart_port[id];
1043 
1044         /* At this point, we've got an empty uart_port struct, initialize it */
1045         spin_lock_init(&port->lock);
1046         port->membase   = NULL;
1047         port->irq       = 0;
1048         port->type      = PORT_UNKNOWN;
1049         port->iotype    = UPIO_MEM32;
1050         port->flags     = UPF_BOOT_AUTOCONF;
1051         port->ops       = &cdns_uart_ops;
1052         port->fifosize  = CDNS_UART_FIFO_SIZE;
1053         port->line      = id;
1054         port->dev       = NULL;
1055         return port;
1056 }
1057 
1058 #ifdef CONFIG_SERIAL_XILINX_PS_UART_CONSOLE
1059 /**
1060  * cdns_uart_console_wait_tx - Wait for the TX to be full
1061  * @port: Handle to the uart port structure
1062  */
1063 static void cdns_uart_console_wait_tx(struct uart_port *port)
1064 {
1065         while (!(readl(port->membase + CDNS_UART_SR) & CDNS_UART_SR_TXEMPTY))
1066                 barrier();
1067 }
1068 
1069 /**
1070  * cdns_uart_console_putchar - write the character to the FIFO buffer
1071  * @port: Handle to the uart port structure
1072  * @ch: Character to be written
1073  */
1074 static void cdns_uart_console_putchar(struct uart_port *port, int ch)
1075 {
1076         cdns_uart_console_wait_tx(port);
1077         writel(ch, port->membase + CDNS_UART_FIFO);
1078 }
1079 
1080 static void __init cdns_early_write(struct console *con, const char *s,
1081                                     unsigned n)
1082 {
1083         struct earlycon_device *dev = con->data;
1084 
1085         uart_console_write(&dev->port, s, n, cdns_uart_console_putchar);
1086 }
1087 
1088 static int __init cdns_early_console_setup(struct earlycon_device *device,
1089                                            const char *opt)
1090 {
1091         if (!device->port.membase)
1092                 return -ENODEV;
1093 
1094         device->con->write = cdns_early_write;
1095 
1096         return 0;
1097 }
1098 OF_EARLYCON_DECLARE(cdns, "xlnx,xuartps", cdns_early_console_setup);
1099 OF_EARLYCON_DECLARE(cdns, "cdns,uart-r1p8", cdns_early_console_setup);
1100 OF_EARLYCON_DECLARE(cdns, "cdns,uart-r1p12", cdns_early_console_setup);
1101 
1102 /**
1103  * cdns_uart_console_write - perform write operation
1104  * @co: Console handle
1105  * @s: Pointer to character array
1106  * @count: No of characters
1107  */
1108 static void cdns_uart_console_write(struct console *co, const char *s,
1109                                 unsigned int count)
1110 {
1111         struct uart_port *port = &cdns_uart_port[co->index];
1112         unsigned long flags;
1113         unsigned int imr, ctrl;
1114         int locked = 1;
1115 
1116         if (port->sysrq)
1117                 locked = 0;
1118         else if (oops_in_progress)
1119                 locked = spin_trylock_irqsave(&port->lock, flags);
1120         else
1121                 spin_lock_irqsave(&port->lock, flags);
1122 
1123         /* save and disable interrupt */
1124         imr = readl(port->membase + CDNS_UART_IMR);
1125         writel(imr, port->membase + CDNS_UART_IDR);
1126 
1127         /*
1128          * Make sure that the tx part is enabled. Set the TX enable bit and
1129          * clear the TX disable bit to enable the transmitter.
1130          */
1131         ctrl = readl(port->membase + CDNS_UART_CR);
1132         ctrl &= ~CDNS_UART_CR_TX_DIS;
1133         ctrl |= CDNS_UART_CR_TX_EN;
1134         writel(ctrl, port->membase + CDNS_UART_CR);
1135 
1136         uart_console_write(port, s, count, cdns_uart_console_putchar);
1137         cdns_uart_console_wait_tx(port);
1138 
1139         writel(ctrl, port->membase + CDNS_UART_CR);
1140 
1141         /* restore interrupt state */
1142         writel(imr, port->membase + CDNS_UART_IER);
1143 
1144         if (locked)
1145                 spin_unlock_irqrestore(&port->lock, flags);
1146 }
1147 
1148 /**
1149  * cdns_uart_console_setup - Initialize the uart to default config
1150  * @co: Console handle
1151  * @options: Initial settings of uart
1152  *
1153  * Return: 0 on success, negative errno otherwise.
1154  */
1155 static int __init cdns_uart_console_setup(struct console *co, char *options)
1156 {
1157         struct uart_port *port = &cdns_uart_port[co->index];
1158         int baud = 9600;
1159         int bits = 8;
1160         int parity = 'n';
1161         int flow = 'n';
1162 
1163         if (co->index < 0 || co->index >= CDNS_UART_NR_PORTS)
1164                 return -EINVAL;
1165 
1166         if (!port->membase) {
1167                 pr_debug("console on " CDNS_UART_TTY_NAME "%i not present\n",
1168                          co->index);
1169                 return -ENODEV;
1170         }
1171 
1172         if (options)
1173                 uart_parse_options(options, &baud, &parity, &bits, &flow);
1174 
1175         return uart_set_options(port, co, baud, parity, bits, flow);
1176 }
1177 
1178 static struct uart_driver cdns_uart_uart_driver;
1179 
1180 static struct console cdns_uart_console = {
1181         .name   = CDNS_UART_TTY_NAME,
1182         .write  = cdns_uart_console_write,
1183         .device = uart_console_device,
1184         .setup  = cdns_uart_console_setup,
1185         .flags  = CON_PRINTBUFFER,
1186         .index  = -1, /* Specified on the cmdline (e.g. console=ttyPS ) */
1187         .data   = &cdns_uart_uart_driver,
1188 };
1189 
1190 /**
1191  * cdns_uart_console_init - Initialization call
1192  *
1193  * Return: 0 on success, negative errno otherwise
1194  */
1195 static int __init cdns_uart_console_init(void)
1196 {
1197         register_console(&cdns_uart_console);
1198         return 0;
1199 }
1200 
1201 console_initcall(cdns_uart_console_init);
1202 
1203 #endif /* CONFIG_SERIAL_XILINX_PS_UART_CONSOLE */
1204 
1205 static struct uart_driver cdns_uart_uart_driver = {
1206         .owner          = THIS_MODULE,
1207         .driver_name    = CDNS_UART_NAME,
1208         .dev_name       = CDNS_UART_TTY_NAME,
1209         .major          = CDNS_UART_MAJOR,
1210         .minor          = CDNS_UART_MINOR,
1211         .nr             = CDNS_UART_NR_PORTS,
1212 #ifdef CONFIG_SERIAL_XILINX_PS_UART_CONSOLE
1213         .cons           = &cdns_uart_console,
1214 #endif
1215 };
1216 
1217 #ifdef CONFIG_PM_SLEEP
1218 /**
1219  * cdns_uart_suspend - suspend event
1220  * @device: Pointer to the device structure
1221  *
1222  * Return: 0
1223  */
1224 static int cdns_uart_suspend(struct device *device)
1225 {
1226         struct uart_port *port = dev_get_drvdata(device);
1227         struct tty_struct *tty;
1228         struct device *tty_dev;
1229         int may_wake = 0;
1230 
1231         /* Get the tty which could be NULL so don't assume it's valid */
1232         tty = tty_port_tty_get(&port->state->port);
1233         if (tty) {
1234                 tty_dev = tty->dev;
1235                 may_wake = device_may_wakeup(tty_dev);
1236                 tty_kref_put(tty);
1237         }
1238 
1239         /*
1240          * Call the API provided in serial_core.c file which handles
1241          * the suspend.
1242          */
1243         uart_suspend_port(&cdns_uart_uart_driver, port);
1244         if (console_suspend_enabled && !may_wake) {
1245                 struct cdns_uart *cdns_uart = port->private_data;
1246 
1247                 clk_disable(cdns_uart->uartclk);
1248                 clk_disable(cdns_uart->pclk);
1249         } else {
1250                 unsigned long flags = 0;
1251 
1252                 spin_lock_irqsave(&port->lock, flags);
1253                 /* Empty the receive FIFO 1st before making changes */
1254                 while (!(readl(port->membase + CDNS_UART_SR) &
1255                                         CDNS_UART_SR_RXEMPTY))
1256                         readl(port->membase + CDNS_UART_FIFO);
1257                 /* set RX trigger level to 1 */
1258                 writel(1, port->membase + CDNS_UART_RXWM);
1259                 /* disable RX timeout interrups */
1260                 writel(CDNS_UART_IXR_TOUT, port->membase + CDNS_UART_IDR);
1261                 spin_unlock_irqrestore(&port->lock, flags);
1262         }
1263 
1264         return 0;
1265 }
1266 
1267 /**
1268  * cdns_uart_resume - Resume after a previous suspend
1269  * @device: Pointer to the device structure
1270  *
1271  * Return: 0
1272  */
1273 static int cdns_uart_resume(struct device *device)
1274 {
1275         struct uart_port *port = dev_get_drvdata(device);
1276         unsigned long flags = 0;
1277         u32 ctrl_reg;
1278         struct tty_struct *tty;
1279         struct device *tty_dev;
1280         int may_wake = 0;
1281 
1282         /* Get the tty which could be NULL so don't assume it's valid */
1283         tty = tty_port_tty_get(&port->state->port);
1284         if (tty) {
1285                 tty_dev = tty->dev;
1286                 may_wake = device_may_wakeup(tty_dev);
1287                 tty_kref_put(tty);
1288         }
1289 
1290         if (console_suspend_enabled && !may_wake) {
1291                 struct cdns_uart *cdns_uart = port->private_data;
1292 
1293                 clk_enable(cdns_uart->pclk);
1294                 clk_enable(cdns_uart->uartclk);
1295 
1296                 spin_lock_irqsave(&port->lock, flags);
1297 
1298                 /* Set TX/RX Reset */
1299                 ctrl_reg = readl(port->membase + CDNS_UART_CR);
1300                 ctrl_reg |= CDNS_UART_CR_TXRST | CDNS_UART_CR_RXRST;
1301                 writel(ctrl_reg, port->membase + CDNS_UART_CR);
1302                 while (readl(port->membase + CDNS_UART_CR) &
1303                                 (CDNS_UART_CR_TXRST | CDNS_UART_CR_RXRST))
1304                         cpu_relax();
1305 
1306                 /* restore rx timeout value */
1307                 writel(rx_timeout, port->membase + CDNS_UART_RXTOUT);
1308                 /* Enable Tx/Rx */
1309                 ctrl_reg = readl(port->membase + CDNS_UART_CR);
1310                 ctrl_reg &= ~(CDNS_UART_CR_TX_DIS | CDNS_UART_CR_RX_DIS);
1311                 ctrl_reg |= CDNS_UART_CR_TX_EN | CDNS_UART_CR_RX_EN;
1312                 writel(ctrl_reg, port->membase + CDNS_UART_CR);
1313 
1314                 spin_unlock_irqrestore(&port->lock, flags);
1315         } else {
1316                 spin_lock_irqsave(&port->lock, flags);
1317                 /* restore original rx trigger level */
1318                 writel(rx_trigger_level, port->membase + CDNS_UART_RXWM);
1319                 /* enable RX timeout interrupt */
1320                 writel(CDNS_UART_IXR_TOUT, port->membase + CDNS_UART_IER);
1321                 spin_unlock_irqrestore(&port->lock, flags);
1322         }
1323 
1324         return uart_resume_port(&cdns_uart_uart_driver, port);
1325 }
1326 #endif /* ! CONFIG_PM_SLEEP */
1327 
1328 static SIMPLE_DEV_PM_OPS(cdns_uart_dev_pm_ops, cdns_uart_suspend,
1329                 cdns_uart_resume);
1330 
1331 /**
1332  * cdns_uart_probe - Platform driver probe
1333  * @pdev: Pointer to the platform device structure
1334  *
1335  * Return: 0 on success, negative errno otherwise
1336  */
1337 static int cdns_uart_probe(struct platform_device *pdev)
1338 {
1339         int rc, id, irq;
1340         struct uart_port *port;
1341         struct resource *res;
1342         struct cdns_uart *cdns_uart_data;
1343 
1344         cdns_uart_data = devm_kzalloc(&pdev->dev, sizeof(*cdns_uart_data),
1345                         GFP_KERNEL);
1346         if (!cdns_uart_data)
1347                 return -ENOMEM;
1348 
1349         cdns_uart_data->pclk = devm_clk_get(&pdev->dev, "pclk");
1350         if (IS_ERR(cdns_uart_data->pclk)) {
1351                 cdns_uart_data->pclk = devm_clk_get(&pdev->dev, "aper_clk");
1352                 if (!IS_ERR(cdns_uart_data->pclk))
1353                         dev_err(&pdev->dev, "clock name 'aper_clk' is deprecated.\n");
1354         }
1355         if (IS_ERR(cdns_uart_data->pclk)) {
1356                 dev_err(&pdev->dev, "pclk clock not found.\n");
1357                 return PTR_ERR(cdns_uart_data->pclk);
1358         }
1359 
1360         cdns_uart_data->uartclk = devm_clk_get(&pdev->dev, "uart_clk");
1361         if (IS_ERR(cdns_uart_data->uartclk)) {
1362                 cdns_uart_data->uartclk = devm_clk_get(&pdev->dev, "ref_clk");
1363                 if (!IS_ERR(cdns_uart_data->uartclk))
1364                         dev_err(&pdev->dev, "clock name 'ref_clk' is deprecated.\n");
1365         }
1366         if (IS_ERR(cdns_uart_data->uartclk)) {
1367                 dev_err(&pdev->dev, "uart_clk clock not found.\n");
1368                 return PTR_ERR(cdns_uart_data->uartclk);
1369         }
1370 
1371         rc = clk_prepare(cdns_uart_data->pclk);
1372         if (rc) {
1373                 dev_err(&pdev->dev, "Unable to enable pclk clock.\n");
1374                 return rc;
1375         }
1376         rc = clk_prepare(cdns_uart_data->uartclk);
1377         if (rc) {
1378                 dev_err(&pdev->dev, "Unable to enable device clock.\n");
1379                 goto err_out_clk_dis_pclk;
1380         }
1381 
1382         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1383         if (!res) {
1384                 rc = -ENODEV;
1385                 goto err_out_clk_disable;
1386         }
1387 
1388         irq = platform_get_irq(pdev, 0);
1389         if (irq <= 0) {
1390                 rc = -ENXIO;
1391                 goto err_out_clk_disable;
1392         }
1393 
1394 #ifdef CONFIG_COMMON_CLK
1395         cdns_uart_data->clk_rate_change_nb.notifier_call =
1396                         cdns_uart_clk_notifier_cb;
1397         if (clk_notifier_register(cdns_uart_data->uartclk,
1398                                 &cdns_uart_data->clk_rate_change_nb))
1399                 dev_warn(&pdev->dev, "Unable to register clock notifier.\n");
1400 #endif
1401         /* Look for a serialN alias */
1402         id = of_alias_get_id(pdev->dev.of_node, "serial");
1403         if (id < 0)
1404                 id = 0;
1405 
1406         /* Initialize the port structure */
1407         port = cdns_uart_get_port(id);
1408 
1409         if (!port) {
1410                 dev_err(&pdev->dev, "Cannot get uart_port structure\n");
1411                 rc = -ENODEV;
1412                 goto err_out_notif_unreg;
1413         }
1414 
1415         /*
1416          * Register the port.
1417          * This function also registers this device with the tty layer
1418          * and triggers invocation of the config_port() entry point.
1419          */
1420         port->mapbase = res->start;
1421         port->irq = irq;
1422         port->dev = &pdev->dev;
1423         port->uartclk = clk_get_rate(cdns_uart_data->uartclk);
1424         port->private_data = cdns_uart_data;
1425         cdns_uart_data->port = port;
1426         platform_set_drvdata(pdev, port);
1427 
1428         rc = uart_add_one_port(&cdns_uart_uart_driver, port);
1429         if (rc) {
1430                 dev_err(&pdev->dev,
1431                         "uart_add_one_port() failed; err=%i\n", rc);
1432                 goto err_out_notif_unreg;
1433         }
1434 
1435         return 0;
1436 
1437 err_out_notif_unreg:
1438 #ifdef CONFIG_COMMON_CLK
1439         clk_notifier_unregister(cdns_uart_data->uartclk,
1440                         &cdns_uart_data->clk_rate_change_nb);
1441 #endif
1442 err_out_clk_disable:
1443         clk_unprepare(cdns_uart_data->uartclk);
1444 err_out_clk_dis_pclk:
1445         clk_unprepare(cdns_uart_data->pclk);
1446 
1447         return rc;
1448 }
1449 
1450 /**
1451  * cdns_uart_remove - called when the platform driver is unregistered
1452  * @pdev: Pointer to the platform device structure
1453  *
1454  * Return: 0 on success, negative errno otherwise
1455  */
1456 static int cdns_uart_remove(struct platform_device *pdev)
1457 {
1458         struct uart_port *port = platform_get_drvdata(pdev);
1459         struct cdns_uart *cdns_uart_data = port->private_data;
1460         int rc;
1461 
1462         /* Remove the cdns_uart port from the serial core */
1463 #ifdef CONFIG_COMMON_CLK
1464         clk_notifier_unregister(cdns_uart_data->uartclk,
1465                         &cdns_uart_data->clk_rate_change_nb);
1466 #endif
1467         rc = uart_remove_one_port(&cdns_uart_uart_driver, port);
1468         port->mapbase = 0;
1469         clk_unprepare(cdns_uart_data->uartclk);
1470         clk_unprepare(cdns_uart_data->pclk);
1471         return rc;
1472 }
1473 
1474 /* Match table for of_platform binding */
1475 static const struct of_device_id cdns_uart_of_match[] = {
1476         { .compatible = "xlnx,xuartps", },
1477         { .compatible = "cdns,uart-r1p8", },
1478         {}
1479 };
1480 MODULE_DEVICE_TABLE(of, cdns_uart_of_match);
1481 
1482 static struct platform_driver cdns_uart_platform_driver = {
1483         .probe   = cdns_uart_probe,
1484         .remove  = cdns_uart_remove,
1485         .driver  = {
1486                 .name = CDNS_UART_NAME,
1487                 .of_match_table = cdns_uart_of_match,
1488                 .pm = &cdns_uart_dev_pm_ops,
1489                 },
1490 };
1491 
1492 static int __init cdns_uart_init(void)
1493 {
1494         int retval = 0;
1495 
1496         /* Register the cdns_uart driver with the serial core */
1497         retval = uart_register_driver(&cdns_uart_uart_driver);
1498         if (retval)
1499                 return retval;
1500 
1501         /* Register the platform driver */
1502         retval = platform_driver_register(&cdns_uart_platform_driver);
1503         if (retval)
1504                 uart_unregister_driver(&cdns_uart_uart_driver);
1505 
1506         return retval;
1507 }
1508 
1509 static void __exit cdns_uart_exit(void)
1510 {
1511         /* Unregister the platform driver */
1512         platform_driver_unregister(&cdns_uart_platform_driver);
1513 
1514         /* Unregister the cdns_uart driver */
1515         uart_unregister_driver(&cdns_uart_uart_driver);
1516 }
1517 
1518 module_init(cdns_uart_init);
1519 module_exit(cdns_uart_exit);
1520 
1521 MODULE_DESCRIPTION("Driver for Cadence UART");
1522 MODULE_AUTHOR("Xilinx Inc.");
1523 MODULE_LICENSE("GPL");
1524 

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