Root/drivers/tty/serial/uartlite.c

1/*
2 * uartlite.c: Serial driver for Xilinx uartlite serial controller
3 *
4 * Copyright (C) 2006 Peter Korsgaard <jacmet@sunsite.dk>
5 * Copyright (C) 2007 Secret Lab Technologies Ltd.
6 *
7 * This file is licensed under the terms of the GNU General Public License
8 * version 2. This program is licensed "as is" without any warranty of any
9 * kind, whether express or implied.
10 */
11
12#include <linux/platform_device.h>
13#include <linux/module.h>
14#include <linux/console.h>
15#include <linux/serial.h>
16#include <linux/serial_core.h>
17#include <linux/tty.h>
18#include <linux/tty_flip.h>
19#include <linux/delay.h>
20#include <linux/interrupt.h>
21#include <linux/init.h>
22#include <linux/io.h>
23#include <linux/of.h>
24#include <linux/of_address.h>
25#include <linux/of_device.h>
26#include <linux/of_platform.h>
27
28#define ULITE_NAME "ttyUL"
29#define ULITE_MAJOR 204
30#define ULITE_MINOR 187
31#define ULITE_NR_UARTS 4
32
33/* ---------------------------------------------------------------------
34 * Register definitions
35 *
36 * For register details see datasheet:
37 * http://www.xilinx.com/support/documentation/ip_documentation/opb_uartlite.pdf
38 */
39
40#define ULITE_RX 0x00
41#define ULITE_TX 0x04
42#define ULITE_STATUS 0x08
43#define ULITE_CONTROL 0x0c
44
45#define ULITE_REGION 16
46
47#define ULITE_STATUS_RXVALID 0x01
48#define ULITE_STATUS_RXFULL 0x02
49#define ULITE_STATUS_TXEMPTY 0x04
50#define ULITE_STATUS_TXFULL 0x08
51#define ULITE_STATUS_IE 0x10
52#define ULITE_STATUS_OVERRUN 0x20
53#define ULITE_STATUS_FRAME 0x40
54#define ULITE_STATUS_PARITY 0x80
55
56#define ULITE_CONTROL_RST_TX 0x01
57#define ULITE_CONTROL_RST_RX 0x02
58#define ULITE_CONTROL_IE 0x10
59
60struct uartlite_reg_ops {
61    u32 (*in)(void __iomem *addr);
62    void (*out)(u32 val, void __iomem *addr);
63};
64
65static u32 uartlite_inbe32(void __iomem *addr)
66{
67    return ioread32be(addr);
68}
69
70static void uartlite_outbe32(u32 val, void __iomem *addr)
71{
72    iowrite32be(val, addr);
73}
74
75static struct uartlite_reg_ops uartlite_be = {
76    .in = uartlite_inbe32,
77    .out = uartlite_outbe32,
78};
79
80static u32 uartlite_inle32(void __iomem *addr)
81{
82    return ioread32(addr);
83}
84
85static void uartlite_outle32(u32 val, void __iomem *addr)
86{
87    iowrite32(val, addr);
88}
89
90static struct uartlite_reg_ops uartlite_le = {
91    .in = uartlite_inle32,
92    .out = uartlite_outle32,
93};
94
95static inline u32 uart_in32(u32 offset, struct uart_port *port)
96{
97    struct uartlite_reg_ops *reg_ops = port->private_data;
98
99    return reg_ops->in(port->membase + offset);
100}
101
102static inline void uart_out32(u32 val, u32 offset, struct uart_port *port)
103{
104    struct uartlite_reg_ops *reg_ops = port->private_data;
105
106    reg_ops->out(val, port->membase + offset);
107}
108
109static struct uart_port ulite_ports[ULITE_NR_UARTS];
110
111/* ---------------------------------------------------------------------
112 * Core UART driver operations
113 */
114
115static int ulite_receive(struct uart_port *port, int stat)
116{
117    struct tty_port *tport = &port->state->port;
118    unsigned char ch = 0;
119    char flag = TTY_NORMAL;
120
121    if ((stat & (ULITE_STATUS_RXVALID | ULITE_STATUS_OVERRUN
122             | ULITE_STATUS_FRAME)) == 0)
123        return 0;
124
125    /* stats */
126    if (stat & ULITE_STATUS_RXVALID) {
127        port->icount.rx++;
128        ch = uart_in32(ULITE_RX, port);
129
130        if (stat & ULITE_STATUS_PARITY)
131            port->icount.parity++;
132    }
133
134    if (stat & ULITE_STATUS_OVERRUN)
135        port->icount.overrun++;
136
137    if (stat & ULITE_STATUS_FRAME)
138        port->icount.frame++;
139
140
141    /* drop byte with parity error if IGNPAR specificed */
142    if (stat & port->ignore_status_mask & ULITE_STATUS_PARITY)
143        stat &= ~ULITE_STATUS_RXVALID;
144
145    stat &= port->read_status_mask;
146
147    if (stat & ULITE_STATUS_PARITY)
148        flag = TTY_PARITY;
149
150
151    stat &= ~port->ignore_status_mask;
152
153    if (stat & ULITE_STATUS_RXVALID)
154        tty_insert_flip_char(tport, ch, flag);
155
156    if (stat & ULITE_STATUS_FRAME)
157        tty_insert_flip_char(tport, 0, TTY_FRAME);
158
159    if (stat & ULITE_STATUS_OVERRUN)
160        tty_insert_flip_char(tport, 0, TTY_OVERRUN);
161
162    return 1;
163}
164
165static int ulite_transmit(struct uart_port *port, int stat)
166{
167    struct circ_buf *xmit = &port->state->xmit;
168
169    if (stat & ULITE_STATUS_TXFULL)
170        return 0;
171
172    if (port->x_char) {
173        uart_out32(port->x_char, ULITE_TX, port);
174        port->x_char = 0;
175        port->icount.tx++;
176        return 1;
177    }
178
179    if (uart_circ_empty(xmit) || uart_tx_stopped(port))
180        return 0;
181
182    uart_out32(xmit->buf[xmit->tail], ULITE_TX, port);
183    xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE-1);
184    port->icount.tx++;
185
186    /* wake up */
187    if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
188        uart_write_wakeup(port);
189
190    return 1;
191}
192
193static irqreturn_t ulite_isr(int irq, void *dev_id)
194{
195    struct uart_port *port = dev_id;
196    int busy, n = 0;
197
198    do {
199        int stat = uart_in32(ULITE_STATUS, port);
200        busy = ulite_receive(port, stat);
201        busy |= ulite_transmit(port, stat);
202        n++;
203    } while (busy);
204
205    /* work done? */
206    if (n > 1) {
207        tty_flip_buffer_push(&port->state->port);
208        return IRQ_HANDLED;
209    } else {
210        return IRQ_NONE;
211    }
212}
213
214static unsigned int ulite_tx_empty(struct uart_port *port)
215{
216    unsigned long flags;
217    unsigned int ret;
218
219    spin_lock_irqsave(&port->lock, flags);
220    ret = uart_in32(ULITE_STATUS, port);
221    spin_unlock_irqrestore(&port->lock, flags);
222
223    return ret & ULITE_STATUS_TXEMPTY ? TIOCSER_TEMT : 0;
224}
225
226static unsigned int ulite_get_mctrl(struct uart_port *port)
227{
228    return TIOCM_CTS | TIOCM_DSR | TIOCM_CAR;
229}
230
231static void ulite_set_mctrl(struct uart_port *port, unsigned int mctrl)
232{
233    /* N/A */
234}
235
236static void ulite_stop_tx(struct uart_port *port)
237{
238    /* N/A */
239}
240
241static void ulite_start_tx(struct uart_port *port)
242{
243    ulite_transmit(port, uart_in32(ULITE_STATUS, port));
244}
245
246static void ulite_stop_rx(struct uart_port *port)
247{
248    /* don't forward any more data (like !CREAD) */
249    port->ignore_status_mask = ULITE_STATUS_RXVALID | ULITE_STATUS_PARITY
250        | ULITE_STATUS_FRAME | ULITE_STATUS_OVERRUN;
251}
252
253static void ulite_enable_ms(struct uart_port *port)
254{
255    /* N/A */
256}
257
258static void ulite_break_ctl(struct uart_port *port, int ctl)
259{
260    /* N/A */
261}
262
263static int ulite_startup(struct uart_port *port)
264{
265    int ret;
266
267    ret = request_irq(port->irq, ulite_isr, IRQF_SHARED, "uartlite", port);
268    if (ret)
269        return ret;
270
271    uart_out32(ULITE_CONTROL_RST_RX | ULITE_CONTROL_RST_TX,
272        ULITE_CONTROL, port);
273    uart_out32(ULITE_CONTROL_IE, ULITE_CONTROL, port);
274
275    return 0;
276}
277
278static void ulite_shutdown(struct uart_port *port)
279{
280    uart_out32(0, ULITE_CONTROL, port);
281    uart_in32(ULITE_CONTROL, port); /* dummy */
282    free_irq(port->irq, port);
283}
284
285static void ulite_set_termios(struct uart_port *port, struct ktermios *termios,
286                  struct ktermios *old)
287{
288    unsigned long flags;
289    unsigned int baud;
290
291    spin_lock_irqsave(&port->lock, flags);
292
293    port->read_status_mask = ULITE_STATUS_RXVALID | ULITE_STATUS_OVERRUN
294        | ULITE_STATUS_TXFULL;
295
296    if (termios->c_iflag & INPCK)
297        port->read_status_mask |=
298            ULITE_STATUS_PARITY | ULITE_STATUS_FRAME;
299
300    port->ignore_status_mask = 0;
301    if (termios->c_iflag & IGNPAR)
302        port->ignore_status_mask |= ULITE_STATUS_PARITY
303            | ULITE_STATUS_FRAME | ULITE_STATUS_OVERRUN;
304
305    /* ignore all characters if CREAD is not set */
306    if ((termios->c_cflag & CREAD) == 0)
307        port->ignore_status_mask |=
308            ULITE_STATUS_RXVALID | ULITE_STATUS_PARITY
309            | ULITE_STATUS_FRAME | ULITE_STATUS_OVERRUN;
310
311    /* update timeout */
312    baud = uart_get_baud_rate(port, termios, old, 0, 460800);
313    uart_update_timeout(port, termios->c_cflag, baud);
314
315    spin_unlock_irqrestore(&port->lock, flags);
316}
317
318static const char *ulite_type(struct uart_port *port)
319{
320    return port->type == PORT_UARTLITE ? "uartlite" : NULL;
321}
322
323static void ulite_release_port(struct uart_port *port)
324{
325    release_mem_region(port->mapbase, ULITE_REGION);
326    iounmap(port->membase);
327    port->membase = NULL;
328}
329
330static int ulite_request_port(struct uart_port *port)
331{
332    int ret;
333
334    pr_debug("ulite console: port=%p; port->mapbase=%llx\n",
335         port, (unsigned long long) port->mapbase);
336
337    if (!request_mem_region(port->mapbase, ULITE_REGION, "uartlite")) {
338        dev_err(port->dev, "Memory region busy\n");
339        return -EBUSY;
340    }
341
342    port->membase = ioremap(port->mapbase, ULITE_REGION);
343    if (!port->membase) {
344        dev_err(port->dev, "Unable to map registers\n");
345        release_mem_region(port->mapbase, ULITE_REGION);
346        return -EBUSY;
347    }
348
349    port->private_data = &uartlite_be;
350    ret = uart_in32(ULITE_CONTROL, port);
351    uart_out32(ULITE_CONTROL_RST_TX, ULITE_CONTROL, port);
352    ret = uart_in32(ULITE_STATUS, port);
353    /* Endianess detection */
354    if ((ret & ULITE_STATUS_TXEMPTY) != ULITE_STATUS_TXEMPTY)
355        port->private_data = &uartlite_le;
356
357    return 0;
358}
359
360static void ulite_config_port(struct uart_port *port, int flags)
361{
362    if (!ulite_request_port(port))
363        port->type = PORT_UARTLITE;
364}
365
366static int ulite_verify_port(struct uart_port *port, struct serial_struct *ser)
367{
368    /* we don't want the core code to modify any port params */
369    return -EINVAL;
370}
371
372#ifdef CONFIG_CONSOLE_POLL
373static int ulite_get_poll_char(struct uart_port *port)
374{
375    if (!(uart_in32(ULITE_STATUS, port) & ULITE_STATUS_RXVALID))
376        return NO_POLL_CHAR;
377
378    return uart_in32(ULITE_RX, port);
379}
380
381static void ulite_put_poll_char(struct uart_port *port, unsigned char ch)
382{
383    while (uart_in32(ULITE_STATUS, port) & ULITE_STATUS_TXFULL)
384        cpu_relax();
385
386    /* write char to device */
387    uart_out32(ch, ULITE_TX, port);
388}
389#endif
390
391static struct uart_ops ulite_ops = {
392    .tx_empty = ulite_tx_empty,
393    .set_mctrl = ulite_set_mctrl,
394    .get_mctrl = ulite_get_mctrl,
395    .stop_tx = ulite_stop_tx,
396    .start_tx = ulite_start_tx,
397    .stop_rx = ulite_stop_rx,
398    .enable_ms = ulite_enable_ms,
399    .break_ctl = ulite_break_ctl,
400    .startup = ulite_startup,
401    .shutdown = ulite_shutdown,
402    .set_termios = ulite_set_termios,
403    .type = ulite_type,
404    .release_port = ulite_release_port,
405    .request_port = ulite_request_port,
406    .config_port = ulite_config_port,
407    .verify_port = ulite_verify_port,
408#ifdef CONFIG_CONSOLE_POLL
409    .poll_get_char = ulite_get_poll_char,
410    .poll_put_char = ulite_put_poll_char,
411#endif
412};
413
414/* ---------------------------------------------------------------------
415 * Console driver operations
416 */
417
418#ifdef CONFIG_SERIAL_UARTLITE_CONSOLE
419static void ulite_console_wait_tx(struct uart_port *port)
420{
421    int i;
422    u8 val;
423
424    /* Spin waiting for TX fifo to have space available */
425    for (i = 0; i < 100000; i++) {
426        val = uart_in32(ULITE_STATUS, port);
427        if ((val & ULITE_STATUS_TXFULL) == 0)
428            break;
429        cpu_relax();
430    }
431}
432
433static void ulite_console_putchar(struct uart_port *port, int ch)
434{
435    ulite_console_wait_tx(port);
436    uart_out32(ch, ULITE_TX, port);
437}
438
439static void ulite_console_write(struct console *co, const char *s,
440                unsigned int count)
441{
442    struct uart_port *port = &ulite_ports[co->index];
443    unsigned long flags;
444    unsigned int ier;
445    int locked = 1;
446
447    if (oops_in_progress) {
448        locked = spin_trylock_irqsave(&port->lock, flags);
449    } else
450        spin_lock_irqsave(&port->lock, flags);
451
452    /* save and disable interrupt */
453    ier = uart_in32(ULITE_STATUS, port) & ULITE_STATUS_IE;
454    uart_out32(0, ULITE_CONTROL, port);
455
456    uart_console_write(port, s, count, ulite_console_putchar);
457
458    ulite_console_wait_tx(port);
459
460    /* restore interrupt state */
461    if (ier)
462        uart_out32(ULITE_CONTROL_IE, ULITE_CONTROL, port);
463
464    if (locked)
465        spin_unlock_irqrestore(&port->lock, flags);
466}
467
468static int ulite_console_setup(struct console *co, char *options)
469{
470    struct uart_port *port;
471    int baud = 9600;
472    int bits = 8;
473    int parity = 'n';
474    int flow = 'n';
475
476    if (co->index < 0 || co->index >= ULITE_NR_UARTS)
477        return -EINVAL;
478
479    port = &ulite_ports[co->index];
480
481    /* Has the device been initialized yet? */
482    if (!port->mapbase) {
483        pr_debug("console on ttyUL%i not present\n", co->index);
484        return -ENODEV;
485    }
486
487    /* not initialized yet? */
488    if (!port->membase) {
489        if (ulite_request_port(port))
490            return -ENODEV;
491    }
492
493    if (options)
494        uart_parse_options(options, &baud, &parity, &bits, &flow);
495
496    return uart_set_options(port, co, baud, parity, bits, flow);
497}
498
499static struct uart_driver ulite_uart_driver;
500
501static struct console ulite_console = {
502    .name = ULITE_NAME,
503    .write = ulite_console_write,
504    .device = uart_console_device,
505    .setup = ulite_console_setup,
506    .flags = CON_PRINTBUFFER,
507    .index = -1, /* Specified on the cmdline (e.g. console=ttyUL0 ) */
508    .data = &ulite_uart_driver,
509};
510
511static int __init ulite_console_init(void)
512{
513    register_console(&ulite_console);
514    return 0;
515}
516
517console_initcall(ulite_console_init);
518
519#endif /* CONFIG_SERIAL_UARTLITE_CONSOLE */
520
521static struct uart_driver ulite_uart_driver = {
522    .owner = THIS_MODULE,
523    .driver_name = "uartlite",
524    .dev_name = ULITE_NAME,
525    .major = ULITE_MAJOR,
526    .minor = ULITE_MINOR,
527    .nr = ULITE_NR_UARTS,
528#ifdef CONFIG_SERIAL_UARTLITE_CONSOLE
529    .cons = &ulite_console,
530#endif
531};
532
533/* ---------------------------------------------------------------------
534 * Port assignment functions (mapping devices to uart_port structures)
535 */
536
537/** ulite_assign: register a uartlite device with the driver
538 *
539 * @dev: pointer to device structure
540 * @id: requested id number. Pass -1 for automatic port assignment
541 * @base: base address of uartlite registers
542 * @irq: irq number for uartlite
543 *
544 * Returns: 0 on success, <0 otherwise
545 */
546static int ulite_assign(struct device *dev, int id, u32 base, int irq)
547{
548    struct uart_port *port;
549    int rc;
550
551    /* if id = -1; then scan for a free id and use that */
552    if (id < 0) {
553        for (id = 0; id < ULITE_NR_UARTS; id++)
554            if (ulite_ports[id].mapbase == 0)
555                break;
556    }
557    if (id < 0 || id >= ULITE_NR_UARTS) {
558        dev_err(dev, "%s%i too large\n", ULITE_NAME, id);
559        return -EINVAL;
560    }
561
562    if ((ulite_ports[id].mapbase) && (ulite_ports[id].mapbase != base)) {
563        dev_err(dev, "cannot assign to %s%i; it is already in use\n",
564            ULITE_NAME, id);
565        return -EBUSY;
566    }
567
568    port = &ulite_ports[id];
569
570    spin_lock_init(&port->lock);
571    port->fifosize = 16;
572    port->regshift = 2;
573    port->iotype = UPIO_MEM;
574    port->iobase = 1; /* mark port in use */
575    port->mapbase = base;
576    port->membase = NULL;
577    port->ops = &ulite_ops;
578    port->irq = irq;
579    port->flags = UPF_BOOT_AUTOCONF;
580    port->dev = dev;
581    port->type = PORT_UNKNOWN;
582    port->line = id;
583
584    dev_set_drvdata(dev, port);
585
586    /* Register the port */
587    rc = uart_add_one_port(&ulite_uart_driver, port);
588    if (rc) {
589        dev_err(dev, "uart_add_one_port() failed; err=%i\n", rc);
590        port->mapbase = 0;
591        dev_set_drvdata(dev, NULL);
592        return rc;
593    }
594
595    return 0;
596}
597
598/** ulite_release: register a uartlite device with the driver
599 *
600 * @dev: pointer to device structure
601 */
602static int ulite_release(struct device *dev)
603{
604    struct uart_port *port = dev_get_drvdata(dev);
605    int rc = 0;
606
607    if (port) {
608        rc = uart_remove_one_port(&ulite_uart_driver, port);
609        dev_set_drvdata(dev, NULL);
610        port->mapbase = 0;
611    }
612
613    return rc;
614}
615
616/* ---------------------------------------------------------------------
617 * Platform bus binding
618 */
619
620#if defined(CONFIG_OF)
621/* Match table for of_platform binding */
622static struct of_device_id ulite_of_match[] = {
623    { .compatible = "xlnx,opb-uartlite-1.00.b", },
624    { .compatible = "xlnx,xps-uartlite-1.00.a", },
625    {}
626};
627MODULE_DEVICE_TABLE(of, ulite_of_match);
628#endif /* CONFIG_OF */
629
630static int ulite_probe(struct platform_device *pdev)
631{
632    struct resource *res, *res2;
633    int id = pdev->id;
634#ifdef CONFIG_OF
635    const __be32 *prop;
636
637    prop = of_get_property(pdev->dev.of_node, "port-number", NULL);
638    if (prop)
639        id = be32_to_cpup(prop);
640#endif
641
642    res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
643    if (!res)
644        return -ENODEV;
645
646    res2 = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
647    if (!res2)
648        return -ENODEV;
649
650    return ulite_assign(&pdev->dev, id, res->start, res2->start);
651}
652
653static int ulite_remove(struct platform_device *pdev)
654{
655    return ulite_release(&pdev->dev);
656}
657
658/* work with hotplug and coldplug */
659MODULE_ALIAS("platform:uartlite");
660
661static struct platform_driver ulite_platform_driver = {
662    .probe = ulite_probe,
663    .remove = ulite_remove,
664    .driver = {
665        .owner = THIS_MODULE,
666        .name = "uartlite",
667        .of_match_table = of_match_ptr(ulite_of_match),
668    },
669};
670
671/* ---------------------------------------------------------------------
672 * Module setup/teardown
673 */
674
675static int __init ulite_init(void)
676{
677    int ret;
678
679    pr_debug("uartlite: calling uart_register_driver()\n");
680    ret = uart_register_driver(&ulite_uart_driver);
681    if (ret)
682        goto err_uart;
683
684    pr_debug("uartlite: calling platform_driver_register()\n");
685    ret = platform_driver_register(&ulite_platform_driver);
686    if (ret)
687        goto err_plat;
688
689    return 0;
690
691err_plat:
692    uart_unregister_driver(&ulite_uart_driver);
693err_uart:
694    pr_err("registering uartlite driver failed: err=%i", ret);
695    return ret;
696}
697
698static void __exit ulite_exit(void)
699{
700    platform_driver_unregister(&ulite_platform_driver);
701    uart_unregister_driver(&ulite_uart_driver);
702}
703
704module_init(ulite_init);
705module_exit(ulite_exit);
706
707MODULE_AUTHOR("Peter Korsgaard <jacmet@sunsite.dk>");
708MODULE_DESCRIPTION("Xilinx uartlite serial driver");
709MODULE_LICENSE("GPL");
710

Archive Download this file



interactive