1 /* sunhv.c: Serial driver for SUN4V hypervisor console.
3 * Copyright (C) 2006, 2007 David S. Miller (davem@davemloft.net)
6 #include <linux/kernel.h>
7 #include <linux/errno.h>
9 #include <linux/tty_flip.h>
10 #include <linux/major.h>
11 #include <linux/circ_buf.h>
12 #include <linux/serial.h>
13 #include <linux/sysrq.h>
14 #include <linux/console.h>
15 #include <linux/spinlock.h>
16 #include <linux/slab.h>
17 #include <linux/delay.h>
18 #include <linux/init.h>
19 #include <linux/of_device.h>
21 #include <asm/hypervisor.h>
22 #include <asm/spitfire.h>
25 #include <asm/setup.h>
27 #if defined(CONFIG_MAGIC_SYSRQ)
31 #include <linux/serial_core.h>
32 #include <linux/sunserialcore.h>
34 #define CON_BREAK ((long)-1)
35 #define CON_HUP ((long)-2)
37 #define IGNORE_BREAK 0x1
38 #define IGNORE_ALL 0x2
40 static char *con_write_page
;
41 static char *con_read_page
;
43 static int hung_up
= 0;
45 static void transmit_chars_putchar(struct uart_port
*port
, struct circ_buf
*xmit
)
47 while (!uart_circ_empty(xmit
)) {
48 long status
= sun4v_con_putchar(xmit
->buf
[xmit
->tail
]);
53 xmit
->tail
= (xmit
->tail
+ 1) & (UART_XMIT_SIZE
- 1);
58 static void transmit_chars_write(struct uart_port
*port
, struct circ_buf
*xmit
)
60 while (!uart_circ_empty(xmit
)) {
61 unsigned long ra
= __pa(xmit
->buf
+ xmit
->tail
);
62 unsigned long len
, status
, sent
;
64 len
= CIRC_CNT_TO_END(xmit
->head
, xmit
->tail
,
66 status
= sun4v_con_write(ra
, len
, &sent
);
69 xmit
->tail
= (xmit
->tail
+ sent
) & (UART_XMIT_SIZE
- 1);
70 port
->icount
.tx
+= sent
;
74 static int receive_chars_getchar(struct uart_port
*port
)
76 int saw_console_brk
= 0;
81 long c
= sun4v_con_getchar(&status
);
83 if (status
== HV_EWOULDBLOCK
)
87 if (uart_handle_break(port
))
95 uart_handle_dcd_change(port
, 0);
98 uart_handle_dcd_change(port
, 1);
101 if (port
->state
== NULL
) {
102 uart_handle_sysrq_char(port
, c
);
108 if (uart_handle_sysrq_char(port
, c
))
111 tty_insert_flip_char(&port
->state
->port
, c
, TTY_NORMAL
);
114 return saw_console_brk
;
117 static int receive_chars_read(struct uart_port
*port
)
119 int saw_console_brk
= 0;
122 while (limit
-- > 0) {
123 unsigned long ra
= __pa(con_read_page
);
124 unsigned long bytes_read
, i
;
125 long stat
= sun4v_con_read(ra
, PAGE_SIZE
, &bytes_read
);
127 if (stat
!= HV_EOK
) {
130 if (stat
== CON_BREAK
) {
131 if (uart_handle_break(port
))
136 } else if (stat
== CON_HUP
) {
138 uart_handle_dcd_change(port
, 0);
141 /* HV_EWOULDBLOCK, etc. */
148 uart_handle_dcd_change(port
, 1);
151 for (i
= 0; i
< bytes_read
; i
++)
152 uart_handle_sysrq_char(port
, con_read_page
[i
]);
154 if (port
->state
== NULL
)
157 port
->icount
.rx
+= bytes_read
;
159 tty_insert_flip_string(&port
->state
->port
, con_read_page
,
163 return saw_console_brk
;
167 void (*transmit_chars
)(struct uart_port
*port
, struct circ_buf
*xmit
);
168 int (*receive_chars
)(struct uart_port
*port
);
171 static struct sunhv_ops bychar_ops
= {
172 .transmit_chars
= transmit_chars_putchar
,
173 .receive_chars
= receive_chars_getchar
,
176 static struct sunhv_ops bywrite_ops
= {
177 .transmit_chars
= transmit_chars_write
,
178 .receive_chars
= receive_chars_read
,
181 static struct sunhv_ops
*sunhv_ops
= &bychar_ops
;
183 static struct tty_port
*receive_chars(struct uart_port
*port
)
185 struct tty_port
*tport
= NULL
;
187 if (port
->state
!= NULL
) /* Unopened serial console */
188 tport
= &port
->state
->port
;
190 if (sunhv_ops
->receive_chars(port
))
196 static void transmit_chars(struct uart_port
*port
)
198 struct circ_buf
*xmit
;
203 xmit
= &port
->state
->xmit
;
204 if (uart_circ_empty(xmit
) || uart_tx_stopped(port
))
207 sunhv_ops
->transmit_chars(port
, xmit
);
209 if (uart_circ_chars_pending(xmit
) < WAKEUP_CHARS
)
210 uart_write_wakeup(port
);
213 static irqreturn_t
sunhv_interrupt(int irq
, void *dev_id
)
215 struct uart_port
*port
= dev_id
;
216 struct tty_port
*tport
;
219 spin_lock_irqsave(&port
->lock
, flags
);
220 tport
= receive_chars(port
);
221 transmit_chars(port
);
222 spin_unlock_irqrestore(&port
->lock
, flags
);
225 tty_flip_buffer_push(tport
);
230 /* port->lock is not held. */
231 static unsigned int sunhv_tx_empty(struct uart_port
*port
)
233 /* Transmitter is always empty for us. If the circ buffer
234 * is non-empty or there is an x_char pending, our caller
235 * will do the right thing and ignore what we return here.
240 /* port->lock held by caller. */
241 static void sunhv_set_mctrl(struct uart_port
*port
, unsigned int mctrl
)
246 /* port->lock is held by caller and interrupts are disabled. */
247 static unsigned int sunhv_get_mctrl(struct uart_port
*port
)
249 return TIOCM_DSR
| TIOCM_CAR
| TIOCM_CTS
;
252 /* port->lock held by caller. */
253 static void sunhv_stop_tx(struct uart_port
*port
)
258 /* port->lock held by caller. */
259 static void sunhv_start_tx(struct uart_port
*port
)
261 transmit_chars(port
);
264 /* port->lock is not held. */
265 static void sunhv_send_xchar(struct uart_port
*port
, char ch
)
270 if (ch
== __DISABLED_CHAR
)
273 spin_lock_irqsave(&port
->lock
, flags
);
275 while (limit
-- > 0) {
276 long status
= sun4v_con_putchar(ch
);
277 if (status
== HV_EOK
)
282 spin_unlock_irqrestore(&port
->lock
, flags
);
285 /* port->lock held by caller. */
286 static void sunhv_stop_rx(struct uart_port
*port
)
290 /* port->lock is not held. */
291 static void sunhv_break_ctl(struct uart_port
*port
, int break_state
)
297 spin_lock_irqsave(&port
->lock
, flags
);
299 while (limit
-- > 0) {
300 long status
= sun4v_con_putchar(CON_BREAK
);
301 if (status
== HV_EOK
)
306 spin_unlock_irqrestore(&port
->lock
, flags
);
310 /* port->lock is not held. */
311 static int sunhv_startup(struct uart_port
*port
)
316 /* port->lock is not held. */
317 static void sunhv_shutdown(struct uart_port
*port
)
321 /* port->lock is not held. */
322 static void sunhv_set_termios(struct uart_port
*port
, struct ktermios
*termios
,
323 struct ktermios
*old
)
325 unsigned int baud
= uart_get_baud_rate(port
, termios
, old
, 0, 4000000);
326 unsigned int quot
= uart_get_divisor(port
, baud
);
327 unsigned int iflag
, cflag
;
330 spin_lock_irqsave(&port
->lock
, flags
);
332 iflag
= termios
->c_iflag
;
333 cflag
= termios
->c_cflag
;
335 port
->ignore_status_mask
= 0;
337 port
->ignore_status_mask
|= IGNORE_BREAK
;
338 if ((cflag
& CREAD
) == 0)
339 port
->ignore_status_mask
|= IGNORE_ALL
;
342 uart_update_timeout(port
, cflag
,
343 (port
->uartclk
/ (16 * quot
)));
345 spin_unlock_irqrestore(&port
->lock
, flags
);
348 static const char *sunhv_type(struct uart_port
*port
)
350 return "SUN4V HCONS";
353 static void sunhv_release_port(struct uart_port
*port
)
357 static int sunhv_request_port(struct uart_port
*port
)
362 static void sunhv_config_port(struct uart_port
*port
, int flags
)
366 static int sunhv_verify_port(struct uart_port
*port
, struct serial_struct
*ser
)
371 static struct uart_ops sunhv_pops
= {
372 .tx_empty
= sunhv_tx_empty
,
373 .set_mctrl
= sunhv_set_mctrl
,
374 .get_mctrl
= sunhv_get_mctrl
,
375 .stop_tx
= sunhv_stop_tx
,
376 .start_tx
= sunhv_start_tx
,
377 .send_xchar
= sunhv_send_xchar
,
378 .stop_rx
= sunhv_stop_rx
,
379 .break_ctl
= sunhv_break_ctl
,
380 .startup
= sunhv_startup
,
381 .shutdown
= sunhv_shutdown
,
382 .set_termios
= sunhv_set_termios
,
384 .release_port
= sunhv_release_port
,
385 .request_port
= sunhv_request_port
,
386 .config_port
= sunhv_config_port
,
387 .verify_port
= sunhv_verify_port
,
390 static struct uart_driver sunhv_reg
= {
391 .owner
= THIS_MODULE
,
392 .driver_name
= "sunhv",
397 static struct uart_port
*sunhv_port
;
399 /* Copy 's' into the con_write_page, decoding "\n" into
400 * "\r\n" along the way. We have to return two lengths
401 * because the caller needs to know how much to advance
402 * 's' and also how many bytes to output via con_write_page.
404 static int fill_con_write_page(const char *s
, unsigned int n
,
405 unsigned long *page_bytes
)
407 const char *orig_s
= s
;
408 char *p
= con_write_page
;
409 int left
= PAGE_SIZE
;
422 *page_bytes
= p
- con_write_page
;
426 static void sunhv_console_write_paged(struct console
*con
, const char *s
, unsigned n
)
428 struct uart_port
*port
= sunhv_port
;
432 if (port
->sysrq
|| oops_in_progress
)
433 locked
= spin_trylock_irqsave(&port
->lock
, flags
);
435 spin_lock_irqsave(&port
->lock
, flags
);
438 unsigned long ra
= __pa(con_write_page
);
439 unsigned long page_bytes
;
440 unsigned int cpy
= fill_con_write_page(s
, n
,
445 while (page_bytes
> 0) {
446 unsigned long written
;
452 stat
= sun4v_con_write(ra
, page_bytes
,
460 page_bytes
-= written
;
466 spin_unlock_irqrestore(&port
->lock
, flags
);
469 static inline void sunhv_console_putchar(struct uart_port
*port
, char c
)
473 while (limit
-- > 0) {
474 long status
= sun4v_con_putchar(c
);
475 if (status
== HV_EOK
)
481 static void sunhv_console_write_bychar(struct console
*con
, const char *s
, unsigned n
)
483 struct uart_port
*port
= sunhv_port
;
487 if (port
->sysrq
|| oops_in_progress
)
488 locked
= spin_trylock_irqsave(&port
->lock
, flags
);
490 spin_lock_irqsave(&port
->lock
, flags
);
493 } else if (oops_in_progress
) {
494 locked
= spin_trylock(&port
->lock
);
496 spin_lock(&port
->lock
);
498 for (i
= 0; i
< n
; i
++) {
500 sunhv_console_putchar(port
, '\r');
501 sunhv_console_putchar(port
, *s
++);
505 spin_unlock_irqrestore(&port
->lock
, flags
);
508 static struct console sunhv_console
= {
510 .write
= sunhv_console_write_bychar
,
511 .device
= uart_console_device
,
512 .flags
= CON_PRINTBUFFER
,
517 static int hv_probe(struct platform_device
*op
)
519 struct uart_port
*port
;
523 if (op
->archdata
.irqs
[0] == 0xffffffff)
526 port
= kzalloc(sizeof(struct uart_port
), GFP_KERNEL
);
531 if (sun4v_hvapi_register(HV_GRP_CORE
, 1, &minor
) == 0 &&
534 con_write_page
= kzalloc(PAGE_SIZE
, GFP_KERNEL
);
538 con_read_page
= kzalloc(PAGE_SIZE
, GFP_KERNEL
);
540 goto out_free_con_write_page
;
542 sunhv_console
.write
= sunhv_console_write_paged
;
543 sunhv_ops
= &bywrite_ops
;
549 port
->ops
= &sunhv_pops
;
550 port
->type
= PORT_SUNHV
;
551 port
->uartclk
= ( 29491200 / 16 ); /* arbitrary */
553 port
->membase
= (unsigned char __iomem
*) __pa(port
);
555 port
->irq
= op
->archdata
.irqs
[0];
557 port
->dev
= &op
->dev
;
559 err
= sunserial_register_minors(&sunhv_reg
, 1);
561 goto out_free_con_read_page
;
563 sunserial_console_match(&sunhv_console
, op
->dev
.of_node
,
564 &sunhv_reg
, port
->line
, false);
566 err
= uart_add_one_port(&sunhv_reg
, port
);
568 goto out_unregister_driver
;
570 err
= request_irq(port
->irq
, sunhv_interrupt
, 0, "hvcons", port
);
572 goto out_remove_port
;
574 platform_set_drvdata(op
, port
);
579 uart_remove_one_port(&sunhv_reg
, port
);
581 out_unregister_driver
:
582 sunserial_unregister_minors(&sunhv_reg
, 1);
584 out_free_con_read_page
:
585 kfree(con_read_page
);
587 out_free_con_write_page
:
588 kfree(con_write_page
);
596 static int hv_remove(struct platform_device
*dev
)
598 struct uart_port
*port
= platform_get_drvdata(dev
);
600 free_irq(port
->irq
, port
);
602 uart_remove_one_port(&sunhv_reg
, port
);
604 sunserial_unregister_minors(&sunhv_reg
, 1);
612 static const struct of_device_id hv_match
[] = {
619 .compatible
= "SUNW,sun4v-console",
624 static struct platform_driver hv_driver
= {
627 .of_match_table
= hv_match
,
633 static int __init
sunhv_init(void)
635 if (tlb_type
!= hypervisor
)
638 return platform_driver_register(&hv_driver
);
640 device_initcall(sunhv_init
);
642 #if 0 /* ...def MODULE ; never supported as such */
643 MODULE_AUTHOR("David S. Miller");
644 MODULE_DESCRIPTION("SUN4V Hypervisor console driver");
645 MODULE_VERSION("2.0");
646 MODULE_LICENSE("GPL");