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14#include <linux/module.h>
15#include <linux/console.h>
16#include <linux/serial_core.h>
17#include <linux/serial.h>
18#include <linux/clk.h>
19#include <linux/io.h>
20#include <linux/tty.h>
21#include <linux/tty_flip.h>
22#include <linux/of.h>
23#include <linux/platform_device.h>
24#include <linux/workqueue.h>
25
26#define UA_ENABLE 0x00
27#define UA_ENABLE_ENABLE BIT(0)
28
29#define UA_CONTROL 0x01
30#define UA_CONTROL_RX_ENABLE BIT(0)
31#define UA_CONTROL_TX_ENABLE BIT(1)
32#define UA_CONTROL_SOFT_RESET BIT(2)
33
34#define UA_STATUS 0x02
35#define UA_STATUS_PARITY_ERR BIT(0)
36#define UA_STATUS_FRAME_ERR BIT(1)
37#define UA_STATUS_OVERRUN_ERR BIT(2)
38#define UA_STATUS_TX_READY BIT(6)
39
40#define UA_CONFIG 0x03
41#define UA_CONFIG_CHAR_LEN BIT(0)
42#define UA_CONFIG_STOP_BITS BIT(1)
43#define UA_CONFIG_PARITY BIT(2)
44#define UA_CONFIG_ODD_PARITY BIT(4)
45
46#define UA_EMI_REC 0x04
47
48#define UA_HBAUD_LO 0x08
49#define UA_HBAUD_HI 0x09
50
51#define UA_STATUS_FIFO 0x0a
52#define UA_STATUS_FIFO_RX_EMPTY BIT(2)
53#define UA_STATUS_FIFO_RX_INT_ALMOST BIT(3)
54#define UA_STATUS_FIFO_TX_FULL BIT(4)
55#define UA_STATUS_FIFO_TX_INT_ALMOST BIT(7)
56
57#define UA_CONFIG_FIFO 0x0b
58#define UA_CONFIG_FIFO_RX_THRESH 7
59#define UA_CONFIG_FIFO_RX_FIFO_MODE BIT(3)
60#define UA_CONFIG_FIFO_TX_FIFO_MODE BIT(7)
61
62#define UA_INTFLAG_CLEAR 0x1c
63#define UA_INTFLAG_SET 0x1d
64#define UA_INT_ENABLE 0x1e
65#define UA_INT_STATUS 0x1f
66
67#define UA_INT_TX BIT(0)
68#define UA_INT_RX BIT(1)
69
70#define DIGICOLOR_USART_NR 3
71
72
73
74
75
76
77
78
79
80struct digicolor_port {
81 struct uart_port port;
82 struct delayed_work rx_poll_work;
83};
84
85static struct uart_port *digicolor_ports[DIGICOLOR_USART_NR];
86
87static bool digicolor_uart_tx_full(struct uart_port *port)
88{
89 return !!(readb_relaxed(port->membase + UA_STATUS_FIFO) &
90 UA_STATUS_FIFO_TX_FULL);
91}
92
93static bool digicolor_uart_rx_empty(struct uart_port *port)
94{
95 return !!(readb_relaxed(port->membase + UA_STATUS_FIFO) &
96 UA_STATUS_FIFO_RX_EMPTY);
97}
98
99static void digicolor_uart_stop_tx(struct uart_port *port)
100{
101 u8 int_enable = readb_relaxed(port->membase + UA_INT_ENABLE);
102
103 int_enable &= ~UA_INT_TX;
104 writeb_relaxed(int_enable, port->membase + UA_INT_ENABLE);
105}
106
107static void digicolor_uart_start_tx(struct uart_port *port)
108{
109 u8 int_enable = readb_relaxed(port->membase + UA_INT_ENABLE);
110
111 int_enable |= UA_INT_TX;
112 writeb_relaxed(int_enable, port->membase + UA_INT_ENABLE);
113}
114
115static void digicolor_uart_stop_rx(struct uart_port *port)
116{
117 u8 int_enable = readb_relaxed(port->membase + UA_INT_ENABLE);
118
119 int_enable &= ~UA_INT_RX;
120 writeb_relaxed(int_enable, port->membase + UA_INT_ENABLE);
121}
122
123static void digicolor_rx_poll(struct work_struct *work)
124{
125 struct digicolor_port *dp =
126 container_of(to_delayed_work(work),
127 struct digicolor_port, rx_poll_work);
128
129 if (!digicolor_uart_rx_empty(&dp->port))
130
131 writeb_relaxed(UA_INT_RX, dp->port.membase + UA_INTFLAG_SET);
132
133 schedule_delayed_work(&dp->rx_poll_work, msecs_to_jiffies(100));
134}
135
136static void digicolor_uart_rx(struct uart_port *port)
137{
138 unsigned long flags;
139
140 spin_lock_irqsave(&port->lock, flags);
141
142 while (1) {
143 u8 status, ch;
144 unsigned int ch_flag;
145
146 if (digicolor_uart_rx_empty(port))
147 break;
148
149 ch = readb_relaxed(port->membase + UA_EMI_REC);
150 status = readb_relaxed(port->membase + UA_STATUS);
151
152 port->icount.rx++;
153 ch_flag = TTY_NORMAL;
154
155 if (status) {
156 if (status & UA_STATUS_PARITY_ERR)
157 port->icount.parity++;
158 else if (status & UA_STATUS_FRAME_ERR)
159 port->icount.frame++;
160 else if (status & UA_STATUS_OVERRUN_ERR)
161 port->icount.overrun++;
162
163 status &= port->read_status_mask;
164
165 if (status & UA_STATUS_PARITY_ERR)
166 ch_flag = TTY_PARITY;
167 else if (status & UA_STATUS_FRAME_ERR)
168 ch_flag = TTY_FRAME;
169 else if (status & UA_STATUS_OVERRUN_ERR)
170 ch_flag = TTY_OVERRUN;
171 }
172
173 if (status & port->ignore_status_mask)
174 continue;
175
176 uart_insert_char(port, status, UA_STATUS_OVERRUN_ERR, ch,
177 ch_flag);
178 }
179
180 spin_unlock_irqrestore(&port->lock, flags);
181
182 tty_flip_buffer_push(&port->state->port);
183}
184
185static void digicolor_uart_tx(struct uart_port *port)
186{
187 struct circ_buf *xmit = &port->state->xmit;
188 unsigned long flags;
189
190 if (digicolor_uart_tx_full(port))
191 return;
192
193 spin_lock_irqsave(&port->lock, flags);
194
195 if (port->x_char) {
196 writeb_relaxed(port->x_char, port->membase + UA_EMI_REC);
197 port->icount.tx++;
198 port->x_char = 0;
199 goto out;
200 }
201
202 if (uart_circ_empty(xmit) || uart_tx_stopped(port)) {
203 digicolor_uart_stop_tx(port);
204 goto out;
205 }
206
207 while (!uart_circ_empty(xmit)) {
208 writeb(xmit->buf[xmit->tail], port->membase + UA_EMI_REC);
209 xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
210 port->icount.tx++;
211
212 if (digicolor_uart_tx_full(port))
213 break;
214 }
215
216 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
217 uart_write_wakeup(port);
218
219out:
220 spin_unlock_irqrestore(&port->lock, flags);
221}
222
223static irqreturn_t digicolor_uart_int(int irq, void *dev_id)
224{
225 struct uart_port *port = dev_id;
226 u8 int_status = readb_relaxed(port->membase + UA_INT_STATUS);
227
228 writeb_relaxed(UA_INT_RX | UA_INT_TX,
229 port->membase + UA_INTFLAG_CLEAR);
230
231 if (int_status & UA_INT_RX)
232 digicolor_uart_rx(port);
233 if (int_status & UA_INT_TX)
234 digicolor_uart_tx(port);
235
236 return IRQ_HANDLED;
237}
238
239static unsigned int digicolor_uart_tx_empty(struct uart_port *port)
240{
241 u8 status = readb_relaxed(port->membase + UA_STATUS);
242
243 return (status & UA_STATUS_TX_READY) ? TIOCSER_TEMT : 0;
244}
245
246static unsigned int digicolor_uart_get_mctrl(struct uart_port *port)
247{
248 return TIOCM_CTS;
249}
250
251static void digicolor_uart_set_mctrl(struct uart_port *port, unsigned int mctrl)
252{
253}
254
255static void digicolor_uart_break_ctl(struct uart_port *port, int state)
256{
257}
258
259static int digicolor_uart_startup(struct uart_port *port)
260{
261 struct digicolor_port *dp =
262 container_of(port, struct digicolor_port, port);
263
264 writeb_relaxed(UA_ENABLE_ENABLE, port->membase + UA_ENABLE);
265 writeb_relaxed(UA_CONTROL_SOFT_RESET, port->membase + UA_CONTROL);
266 writeb_relaxed(0, port->membase + UA_CONTROL);
267
268 writeb_relaxed(UA_CONFIG_FIFO_RX_FIFO_MODE
269 | UA_CONFIG_FIFO_TX_FIFO_MODE | UA_CONFIG_FIFO_RX_THRESH,
270 port->membase + UA_CONFIG_FIFO);
271 writeb_relaxed(UA_STATUS_FIFO_RX_INT_ALMOST,
272 port->membase + UA_STATUS_FIFO);
273 writeb_relaxed(UA_CONTROL_RX_ENABLE | UA_CONTROL_TX_ENABLE,
274 port->membase + UA_CONTROL);
275 writeb_relaxed(UA_INT_TX | UA_INT_RX,
276 port->membase + UA_INT_ENABLE);
277
278 schedule_delayed_work(&dp->rx_poll_work, msecs_to_jiffies(100));
279
280 return 0;
281}
282
283static void digicolor_uart_shutdown(struct uart_port *port)
284{
285 struct digicolor_port *dp =
286 container_of(port, struct digicolor_port, port);
287
288 writeb_relaxed(0, port->membase + UA_ENABLE);
289 cancel_delayed_work_sync(&dp->rx_poll_work);
290}
291
292static void digicolor_uart_set_termios(struct uart_port *port,
293 struct ktermios *termios,
294 struct ktermios *old)
295{
296 unsigned int baud, divisor;
297 u8 config = 0;
298 unsigned long flags;
299
300
301 termios->c_cflag &= ~CMSPAR;
302 termios->c_iflag &= ~(BRKINT | IGNBRK);
303
304
305 baud = uart_get_baud_rate(port, termios, old,
306 port->uartclk / (0x10000*16),
307 port->uartclk / 256);
308 divisor = uart_get_divisor(port, baud) - 1;
309
310 switch (termios->c_cflag & CSIZE) {
311 case CS7:
312 break;
313 case CS8:
314 default:
315 config |= UA_CONFIG_CHAR_LEN;
316 break;
317 }
318
319 if (termios->c_cflag & CSTOPB)
320 config |= UA_CONFIG_STOP_BITS;
321
322 if (termios->c_cflag & PARENB) {
323 config |= UA_CONFIG_PARITY;
324 if (termios->c_cflag & PARODD)
325 config |= UA_CONFIG_ODD_PARITY;
326 }
327
328
329 port->read_status_mask = UA_STATUS_OVERRUN_ERR;
330 if (termios->c_iflag & INPCK)
331 port->read_status_mask |= UA_STATUS_PARITY_ERR
332 | UA_STATUS_FRAME_ERR;
333
334
335 port->ignore_status_mask = 0;
336 if (!(termios->c_cflag & CREAD))
337 port->ignore_status_mask |= UA_STATUS_OVERRUN_ERR
338 | UA_STATUS_PARITY_ERR | UA_STATUS_FRAME_ERR;
339
340 spin_lock_irqsave(&port->lock, flags);
341
342 uart_update_timeout(port, termios->c_cflag, baud);
343
344 writeb_relaxed(config, port->membase + UA_CONFIG);
345 writeb_relaxed(divisor & 0xff, port->membase + UA_HBAUD_LO);
346 writeb_relaxed(divisor >> 8, port->membase + UA_HBAUD_HI);
347
348 spin_unlock_irqrestore(&port->lock, flags);
349}
350
351static const char *digicolor_uart_type(struct uart_port *port)
352{
353 return (port->type == PORT_DIGICOLOR) ? "DIGICOLOR USART" : NULL;
354}
355
356static void digicolor_uart_config_port(struct uart_port *port, int flags)
357{
358 if (flags & UART_CONFIG_TYPE)
359 port->type = PORT_DIGICOLOR;
360}
361
362static void digicolor_uart_release_port(struct uart_port *port)
363{
364}
365
366static int digicolor_uart_request_port(struct uart_port *port)
367{
368 return 0;
369}
370
371static const struct uart_ops digicolor_uart_ops = {
372 .tx_empty = digicolor_uart_tx_empty,
373 .set_mctrl = digicolor_uart_set_mctrl,
374 .get_mctrl = digicolor_uart_get_mctrl,
375 .stop_tx = digicolor_uart_stop_tx,
376 .start_tx = digicolor_uart_start_tx,
377 .stop_rx = digicolor_uart_stop_rx,
378 .break_ctl = digicolor_uart_break_ctl,
379 .startup = digicolor_uart_startup,
380 .shutdown = digicolor_uart_shutdown,
381 .set_termios = digicolor_uart_set_termios,
382 .type = digicolor_uart_type,
383 .config_port = digicolor_uart_config_port,
384 .release_port = digicolor_uart_release_port,
385 .request_port = digicolor_uart_request_port,
386};
387
388static void digicolor_uart_console_putchar(struct uart_port *port, int ch)
389{
390 while (digicolor_uart_tx_full(port))
391 cpu_relax();
392
393 writeb_relaxed(ch, port->membase + UA_EMI_REC);
394}
395
396static void digicolor_uart_console_write(struct console *co, const char *c,
397 unsigned n)
398{
399 struct uart_port *port = digicolor_ports[co->index];
400 u8 status;
401 unsigned long flags;
402 int locked = 1;
403
404 if (oops_in_progress)
405 locked = spin_trylock_irqsave(&port->lock, flags);
406 else
407 spin_lock_irqsave(&port->lock, flags);
408
409 uart_console_write(port, c, n, digicolor_uart_console_putchar);
410
411 if (locked)
412 spin_unlock_irqrestore(&port->lock, flags);
413
414
415 do {
416 status = readb_relaxed(port->membase + UA_STATUS);
417 } while ((status & UA_STATUS_TX_READY) == 0);
418}
419
420static int digicolor_uart_console_setup(struct console *co, char *options)
421{
422 int baud = 115200, bits = 8, parity = 'n', flow = 'n';
423 struct uart_port *port;
424
425 if (co->index < 0 || co->index >= DIGICOLOR_USART_NR)
426 return -EINVAL;
427
428 port = digicolor_ports[co->index];
429 if (!port)
430 return -ENODEV;
431
432 if (options)
433 uart_parse_options(options, &baud, &parity, &bits, &flow);
434
435 return uart_set_options(port, co, baud, parity, bits, flow);
436}
437
438static struct console digicolor_console = {
439 .name = "ttyS",
440 .device = uart_console_device,
441 .write = digicolor_uart_console_write,
442 .setup = digicolor_uart_console_setup,
443 .flags = CON_PRINTBUFFER,
444 .index = -1,
445};
446
447static struct uart_driver digicolor_uart = {
448 .driver_name = "digicolor-usart",
449 .dev_name = "ttyS",
450 .nr = DIGICOLOR_USART_NR,
451};
452
453static int digicolor_uart_probe(struct platform_device *pdev)
454{
455 struct device_node *np = pdev->dev.of_node;
456 int irq, ret, index;
457 struct digicolor_port *dp;
458 struct resource *res;
459 struct clk *uart_clk;
460
461 if (!np) {
462 dev_err(&pdev->dev, "Missing device tree node\n");
463 return -ENXIO;
464 }
465
466 index = of_alias_get_id(np, "serial");
467 if (index < 0 || index >= DIGICOLOR_USART_NR)
468 return -EINVAL;
469
470 dp = devm_kzalloc(&pdev->dev, sizeof(*dp), GFP_KERNEL);
471 if (!dp)
472 return -ENOMEM;
473
474 uart_clk = devm_clk_get(&pdev->dev, NULL);
475 if (IS_ERR(uart_clk))
476 return PTR_ERR(uart_clk);
477
478 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
479 dp->port.mapbase = res->start;
480 dp->port.membase = devm_ioremap_resource(&pdev->dev, res);
481 if (IS_ERR(dp->port.membase))
482 return PTR_ERR(dp->port.membase);
483
484 irq = platform_get_irq(pdev, 0);
485 if (irq < 0)
486 return irq;
487 dp->port.irq = irq;
488
489 dp->port.iotype = UPIO_MEM;
490 dp->port.uartclk = clk_get_rate(uart_clk);
491 dp->port.fifosize = 16;
492 dp->port.dev = &pdev->dev;
493 dp->port.ops = &digicolor_uart_ops;
494 dp->port.line = index;
495 dp->port.type = PORT_DIGICOLOR;
496 spin_lock_init(&dp->port.lock);
497
498 digicolor_ports[index] = &dp->port;
499 platform_set_drvdata(pdev, &dp->port);
500
501 INIT_DELAYED_WORK(&dp->rx_poll_work, digicolor_rx_poll);
502
503 ret = devm_request_irq(&pdev->dev, dp->port.irq, digicolor_uart_int, 0,
504 dev_name(&pdev->dev), &dp->port);
505 if (ret)
506 return ret;
507
508 return uart_add_one_port(&digicolor_uart, &dp->port);
509}
510
511static int digicolor_uart_remove(struct platform_device *pdev)
512{
513 struct uart_port *port = platform_get_drvdata(pdev);
514
515 uart_remove_one_port(&digicolor_uart, port);
516
517 return 0;
518}
519
520static const struct of_device_id digicolor_uart_dt_ids[] = {
521 { .compatible = "cnxt,cx92755-usart", },
522 { }
523};
524MODULE_DEVICE_TABLE(of, digicolor_uart_dt_ids);
525
526static struct platform_driver digicolor_uart_platform = {
527 .driver = {
528 .name = "digicolor-usart",
529 .of_match_table = of_match_ptr(digicolor_uart_dt_ids),
530 },
531 .probe = digicolor_uart_probe,
532 .remove = digicolor_uart_remove,
533};
534
535static int __init digicolor_uart_init(void)
536{
537 int ret;
538
539 if (IS_ENABLED(CONFIG_SERIAL_CONEXANT_DIGICOLOR_CONSOLE)) {
540 digicolor_uart.cons = &digicolor_console;
541 digicolor_console.data = &digicolor_uart;
542 }
543
544 ret = uart_register_driver(&digicolor_uart);
545 if (ret)
546 return ret;
547
548 return platform_driver_register(&digicolor_uart_platform);
549}
550module_init(digicolor_uart_init);
551
552static void __exit digicolor_uart_exit(void)
553{
554 platform_driver_unregister(&digicolor_uart_platform);
555 uart_unregister_driver(&digicolor_uart);
556}
557module_exit(digicolor_uart_exit);
558
559MODULE_AUTHOR("Baruch Siach <baruch@tkos.co.il>");
560MODULE_DESCRIPTION("Conexant Digicolor USART serial driver");
561MODULE_LICENSE("GPL");
562
