1 /* sunhv.c: Serial driver for SUN4V hypervisor console.
3 * Copyright (C) 2006, 2007 David S. Miller (davem@davemloft.net)
6 #include <linux/module.h>
7 #include <linux/kernel.h>
8 #include <linux/errno.h>
10 #include <linux/tty_flip.h>
11 #include <linux/major.h>
12 #include <linux/circ_buf.h>
13 #include <linux/serial.h>
14 #include <linux/sysrq.h>
15 #include <linux/console.h>
16 #include <linux/spinlock.h>
17 #include <linux/slab.h>
18 #include <linux/delay.h>
19 #include <linux/init.h>
20 #include <linux/of_device.h>
22 #include <asm/hypervisor.h>
23 #include <asm/spitfire.h>
26 #include <asm/setup.h>
28 #if defined(CONFIG_MAGIC_SYSRQ)
32 #include <linux/serial_core.h>
33 #include <linux/sunserialcore.h>
35 #define CON_BREAK ((long)-1)
36 #define CON_HUP ((long)-2)
38 #define IGNORE_BREAK 0x1
39 #define IGNORE_ALL 0x2
41 static char *con_write_page;
42 static char *con_read_page;
44 static int hung_up = 0;
46 static void transmit_chars_putchar(struct uart_port *port, struct circ_buf *xmit)
48 while (!uart_circ_empty(xmit)) {
49 long status = sun4v_con_putchar(xmit->buf[xmit->tail]);
54 xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
59 static void transmit_chars_write(struct uart_port *port, struct circ_buf *xmit)
61 while (!uart_circ_empty(xmit)) {
62 unsigned long ra = __pa(xmit->buf + xmit->tail);
63 unsigned long len, status, sent;
65 len = CIRC_CNT_TO_END(xmit->head, xmit->tail,
67 status = sun4v_con_write(ra, len, &sent);
70 xmit->tail = (xmit->tail + sent) & (UART_XMIT_SIZE - 1);
71 port->icount.tx += sent;
75 static int receive_chars_getchar(struct uart_port *port)
77 int saw_console_brk = 0;
82 long c = sun4v_con_getchar(&status);
84 if (status == HV_EWOULDBLOCK)
88 if (uart_handle_break(port))
96 uart_handle_dcd_change(port, 0);
99 uart_handle_dcd_change(port, 1);
102 if (port->state == NULL) {
103 uart_handle_sysrq_char(port, c);
109 if (uart_handle_sysrq_char(port, c))
112 tty_insert_flip_char(&port->state->port, c, TTY_NORMAL);
115 return saw_console_brk;
118 static int receive_chars_read(struct uart_port *port)
120 int saw_console_brk = 0;
123 while (limit-- > 0) {
124 unsigned long ra = __pa(con_read_page);
125 unsigned long bytes_read, i;
126 long stat = sun4v_con_read(ra, PAGE_SIZE, &bytes_read);
128 if (stat != HV_EOK) {
131 if (stat == CON_BREAK) {
132 if (uart_handle_break(port))
137 } else if (stat == CON_HUP) {
139 uart_handle_dcd_change(port, 0);
142 /* HV_EWOULDBLOCK, etc. */
149 uart_handle_dcd_change(port, 1);
152 for (i = 0; i < bytes_read; i++)
153 uart_handle_sysrq_char(port, con_read_page[i]);
155 if (port->state == NULL)
158 port->icount.rx += bytes_read;
160 tty_insert_flip_string(&port->state->port, con_read_page,
164 return saw_console_brk;
168 void (*transmit_chars)(struct uart_port *port, struct circ_buf *xmit);
169 int (*receive_chars)(struct uart_port *port);
172 static struct sunhv_ops bychar_ops = {
173 .transmit_chars = transmit_chars_putchar,
174 .receive_chars = receive_chars_getchar,
177 static struct sunhv_ops bywrite_ops = {
178 .transmit_chars = transmit_chars_write,
179 .receive_chars = receive_chars_read,
182 static struct sunhv_ops *sunhv_ops = &bychar_ops;
184 static struct tty_port *receive_chars(struct uart_port *port)
186 struct tty_port *tport = NULL;
188 if (port->state != NULL) /* Unopened serial console */
189 tport = &port->state->port;
191 if (sunhv_ops->receive_chars(port))
197 static void transmit_chars(struct uart_port *port)
199 struct circ_buf *xmit;
204 xmit = &port->state->xmit;
205 if (uart_circ_empty(xmit) || uart_tx_stopped(port))
208 sunhv_ops->transmit_chars(port, xmit);
210 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
211 uart_write_wakeup(port);
214 static irqreturn_t sunhv_interrupt(int irq, void *dev_id)
216 struct uart_port *port = dev_id;
217 struct tty_port *tport;
220 spin_lock_irqsave(&port->lock, flags);
221 tport = receive_chars(port);
222 transmit_chars(port);
223 spin_unlock_irqrestore(&port->lock, flags);
226 tty_flip_buffer_push(tport);
231 /* port->lock is not held. */
232 static unsigned int sunhv_tx_empty(struct uart_port *port)
234 /* Transmitter is always empty for us. If the circ buffer
235 * is non-empty or there is an x_char pending, our caller
236 * will do the right thing and ignore what we return here.
241 /* port->lock held by caller. */
242 static void sunhv_set_mctrl(struct uart_port *port, unsigned int mctrl)
247 /* port->lock is held by caller and interrupts are disabled. */
248 static unsigned int sunhv_get_mctrl(struct uart_port *port)
250 return TIOCM_DSR | TIOCM_CAR | TIOCM_CTS;
253 /* port->lock held by caller. */
254 static void sunhv_stop_tx(struct uart_port *port)
259 /* port->lock held by caller. */
260 static void sunhv_start_tx(struct uart_port *port)
262 transmit_chars(port);
265 /* port->lock is not held. */
266 static void sunhv_send_xchar(struct uart_port *port, char ch)
271 spin_lock_irqsave(&port->lock, flags);
273 while (limit-- > 0) {
274 long status = sun4v_con_putchar(ch);
275 if (status == HV_EOK)
280 spin_unlock_irqrestore(&port->lock, flags);
283 /* port->lock held by caller. */
284 static void sunhv_stop_rx(struct uart_port *port)
288 /* port->lock held by caller. */
289 static void sunhv_enable_ms(struct uart_port *port)
293 /* port->lock is not held. */
294 static void sunhv_break_ctl(struct uart_port *port, int break_state)
300 spin_lock_irqsave(&port->lock, flags);
302 while (limit-- > 0) {
303 long status = sun4v_con_putchar(CON_BREAK);
304 if (status == HV_EOK)
309 spin_unlock_irqrestore(&port->lock, flags);
313 /* port->lock is not held. */
314 static int sunhv_startup(struct uart_port *port)
319 /* port->lock is not held. */
320 static void sunhv_shutdown(struct uart_port *port)
324 /* port->lock is not held. */
325 static void sunhv_set_termios(struct uart_port *port, struct ktermios *termios,
326 struct ktermios *old)
328 unsigned int baud = uart_get_baud_rate(port, termios, old, 0, 4000000);
329 unsigned int quot = uart_get_divisor(port, baud);
330 unsigned int iflag, cflag;
333 spin_lock_irqsave(&port->lock, flags);
335 iflag = termios->c_iflag;
336 cflag = termios->c_cflag;
338 port->ignore_status_mask = 0;
340 port->ignore_status_mask |= IGNORE_BREAK;
341 if ((cflag & CREAD) == 0)
342 port->ignore_status_mask |= IGNORE_ALL;
345 uart_update_timeout(port, cflag,
346 (port->uartclk / (16 * quot)));
348 spin_unlock_irqrestore(&port->lock, flags);
351 static const char *sunhv_type(struct uart_port *port)
353 return "SUN4V HCONS";
356 static void sunhv_release_port(struct uart_port *port)
360 static int sunhv_request_port(struct uart_port *port)
365 static void sunhv_config_port(struct uart_port *port, int flags)
369 static int sunhv_verify_port(struct uart_port *port, struct serial_struct *ser)
374 static struct uart_ops sunhv_pops = {
375 .tx_empty = sunhv_tx_empty,
376 .set_mctrl = sunhv_set_mctrl,
377 .get_mctrl = sunhv_get_mctrl,
378 .stop_tx = sunhv_stop_tx,
379 .start_tx = sunhv_start_tx,
380 .send_xchar = sunhv_send_xchar,
381 .stop_rx = sunhv_stop_rx,
382 .enable_ms = sunhv_enable_ms,
383 .break_ctl = sunhv_break_ctl,
384 .startup = sunhv_startup,
385 .shutdown = sunhv_shutdown,
386 .set_termios = sunhv_set_termios,
388 .release_port = sunhv_release_port,
389 .request_port = sunhv_request_port,
390 .config_port = sunhv_config_port,
391 .verify_port = sunhv_verify_port,
394 static struct uart_driver sunhv_reg = {
395 .owner = THIS_MODULE,
396 .driver_name = "sunhv",
401 static struct uart_port *sunhv_port;
403 /* Copy 's' into the con_write_page, decoding "\n" into
404 * "\r\n" along the way. We have to return two lengths
405 * because the caller needs to know how much to advance
406 * 's' and also how many bytes to output via con_write_page.
408 static int fill_con_write_page(const char *s, unsigned int n,
409 unsigned long *page_bytes)
411 const char *orig_s = s;
412 char *p = con_write_page;
413 int left = PAGE_SIZE;
426 *page_bytes = p - con_write_page;
430 static void sunhv_console_write_paged(struct console *con, const char *s, unsigned n)
432 struct uart_port *port = sunhv_port;
436 if (port->sysrq || oops_in_progress)
437 locked = spin_trylock_irqsave(&port->lock, flags);
439 spin_lock_irqsave(&port->lock, flags);
442 unsigned long ra = __pa(con_write_page);
443 unsigned long page_bytes;
444 unsigned int cpy = fill_con_write_page(s, n,
449 while (page_bytes > 0) {
450 unsigned long written;
456 stat = sun4v_con_write(ra, page_bytes,
464 page_bytes -= written;
470 spin_unlock_irqrestore(&port->lock, flags);
473 static inline void sunhv_console_putchar(struct uart_port *port, char c)
477 while (limit-- > 0) {
478 long status = sun4v_con_putchar(c);
479 if (status == HV_EOK)
485 static void sunhv_console_write_bychar(struct console *con, const char *s, unsigned n)
487 struct uart_port *port = sunhv_port;
491 if (port->sysrq || oops_in_progress)
492 locked = spin_trylock_irqsave(&port->lock, flags);
494 spin_lock_irqsave(&port->lock, flags);
497 } else if (oops_in_progress) {
498 locked = spin_trylock(&port->lock);
500 spin_lock(&port->lock);
502 for (i = 0; i < n; i++) {
504 sunhv_console_putchar(port, '\r');
505 sunhv_console_putchar(port, *s++);
509 spin_unlock_irqrestore(&port->lock, flags);
512 static struct console sunhv_console = {
514 .write = sunhv_console_write_bychar,
515 .device = uart_console_device,
516 .flags = CON_PRINTBUFFER,
521 static int hv_probe(struct platform_device *op)
523 struct uart_port *port;
527 if (op->archdata.irqs[0] == 0xffffffff)
530 port = kzalloc(sizeof(struct uart_port), GFP_KERNEL);
535 if (sun4v_hvapi_register(HV_GRP_CORE, 1, &minor) == 0 &&
538 con_write_page = kzalloc(PAGE_SIZE, GFP_KERNEL);
542 con_read_page = kzalloc(PAGE_SIZE, GFP_KERNEL);
544 goto out_free_con_write_page;
546 sunhv_console.write = sunhv_console_write_paged;
547 sunhv_ops = &bywrite_ops;
553 port->ops = &sunhv_pops;
554 port->type = PORT_SUNHV;
555 port->uartclk = ( 29491200 / 16 ); /* arbitrary */
557 port->membase = (unsigned char __iomem *) __pa(port);
559 port->irq = op->archdata.irqs[0];
561 port->dev = &op->dev;
563 err = sunserial_register_minors(&sunhv_reg, 1);
565 goto out_free_con_read_page;
567 sunserial_console_match(&sunhv_console, op->dev.of_node,
568 &sunhv_reg, port->line, false);
570 err = uart_add_one_port(&sunhv_reg, port);
572 goto out_unregister_driver;
574 err = request_irq(port->irq, sunhv_interrupt, 0, "hvcons", port);
576 goto out_remove_port;
578 platform_set_drvdata(op, port);
583 uart_remove_one_port(&sunhv_reg, port);
585 out_unregister_driver:
586 sunserial_unregister_minors(&sunhv_reg, 1);
588 out_free_con_read_page:
589 kfree(con_read_page);
591 out_free_con_write_page:
592 kfree(con_write_page);
600 static int hv_remove(struct platform_device *dev)
602 struct uart_port *port = platform_get_drvdata(dev);
604 free_irq(port->irq, port);
606 uart_remove_one_port(&sunhv_reg, port);
608 sunserial_unregister_minors(&sunhv_reg, 1);
616 static const struct of_device_id hv_match[] = {
623 .compatible = "SUNW,sun4v-console",
627 MODULE_DEVICE_TABLE(of, hv_match);
629 static struct platform_driver hv_driver = {
632 .owner = THIS_MODULE,
633 .of_match_table = hv_match,
639 static int __init sunhv_init(void)
641 if (tlb_type != hypervisor)
644 return platform_driver_register(&hv_driver);
647 static void __exit sunhv_exit(void)
649 platform_driver_unregister(&hv_driver);
652 module_init(sunhv_init);
653 module_exit(sunhv_exit);
655 MODULE_AUTHOR("David S. Miller");
656 MODULE_DESCRIPTION("SUN4V Hypervisor console driver");
657 MODULE_VERSION("2.0");
658 MODULE_LICENSE("GPL");