1 /* sunhv.c: Serial driver for SUN4V hypervisor console.
3 * Copyright (C) 2006 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>
21 #include <asm/hypervisor.h>
22 #include <asm/spitfire.h>
24 #include <asm/oplib.h>
27 #if defined(CONFIG_MAGIC_SYSRQ)
31 #include <linux/serial_core.h>
35 #define CON_BREAK ((long)-1)
36 #define CON_HUP ((long)-2)
38 static inline long hypervisor_con_getchar(long *status)
40 register unsigned long func asm("%o5");
41 register unsigned long arg0 asm("%o0");
42 register unsigned long arg1 asm("%o1");
44 func = HV_FAST_CONS_GETCHAR;
47 __asm__ __volatile__("ta %6"
48 : "=&r" (func), "=&r" (arg0), "=&r" (arg1)
49 : "0" (func), "1" (arg0), "2" (arg1),
57 static inline long hypervisor_con_putchar(long ch)
59 register unsigned long func asm("%o5");
60 register unsigned long arg0 asm("%o0");
62 func = HV_FAST_CONS_PUTCHAR;
64 __asm__ __volatile__("ta %4"
65 : "=&r" (func), "=&r" (arg0)
66 : "0" (func), "1" (arg0), "i" (HV_FAST_TRAP));
71 #define IGNORE_BREAK 0x1
72 #define IGNORE_ALL 0x2
74 static int hung_up = 0;
76 static struct tty_struct *receive_chars(struct uart_port *port, struct pt_regs *regs)
78 struct tty_struct *tty = NULL;
79 int saw_console_brk = 0;
82 if (port->info != NULL) /* Unopened serial console */
83 tty = port->info->tty;
87 long c = hypervisor_con_getchar(&status);
90 if (status == HV_EWOULDBLOCK)
94 if (uart_handle_break(port))
102 uart_handle_dcd_change(port, 0);
103 } else if (hung_up) {
105 uart_handle_dcd_change(port, 1);
109 uart_handle_sysrq_char(port, c, regs);
115 if (c == CON_BREAK) {
117 if (uart_handle_break(port))
122 if (uart_handle_sysrq_char(port, c, regs))
125 if ((port->ignore_status_mask & IGNORE_ALL) ||
126 ((port->ignore_status_mask & IGNORE_BREAK) &&
130 tty_insert_flip_char(tty, c, flag);
139 static void transmit_chars(struct uart_port *port)
141 struct circ_buf *xmit;
146 xmit = &port->info->xmit;
147 if (uart_circ_empty(xmit) || uart_tx_stopped(port))
150 while (!uart_circ_empty(xmit)) {
151 long status = hypervisor_con_putchar(xmit->buf[xmit->tail]);
153 if (status != HV_EOK)
156 xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
160 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
161 uart_write_wakeup(port);
164 static irqreturn_t sunhv_interrupt(int irq, void *dev_id, struct pt_regs *regs)
166 struct uart_port *port = dev_id;
167 struct tty_struct *tty;
170 spin_lock_irqsave(&port->lock, flags);
171 tty = receive_chars(port, regs);
172 transmit_chars(port);
173 spin_unlock_irqrestore(&port->lock, flags);
176 tty_flip_buffer_push(tty);
181 /* port->lock is not held. */
182 static unsigned int sunhv_tx_empty(struct uart_port *port)
184 /* Transmitter is always empty for us. If the circ buffer
185 * is non-empty or there is an x_char pending, our caller
186 * will do the right thing and ignore what we return here.
191 /* port->lock held by caller. */
192 static void sunhv_set_mctrl(struct uart_port *port, unsigned int mctrl)
197 /* port->lock is held by caller and interrupts are disabled. */
198 static unsigned int sunhv_get_mctrl(struct uart_port *port)
200 return TIOCM_DSR | TIOCM_CAR | TIOCM_CTS;
203 /* port->lock held by caller. */
204 static void sunhv_stop_tx(struct uart_port *port)
209 /* port->lock held by caller. */
210 static void sunhv_start_tx(struct uart_port *port)
212 struct circ_buf *xmit = &port->info->xmit;
215 spin_lock_irqsave(&port->lock, flags);
217 while (!uart_circ_empty(xmit)) {
218 long status = hypervisor_con_putchar(xmit->buf[xmit->tail]);
220 if (status != HV_EOK)
223 xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
227 spin_unlock_irqrestore(&port->lock, flags);
230 /* port->lock is not held. */
231 static void sunhv_send_xchar(struct uart_port *port, char ch)
236 spin_lock_irqsave(&port->lock, flags);
238 while (limit-- > 0) {
239 long status = hypervisor_con_putchar(ch);
240 if (status == HV_EOK)
244 spin_unlock_irqrestore(&port->lock, flags);
247 /* port->lock held by caller. */
248 static void sunhv_stop_rx(struct uart_port *port)
252 /* port->lock held by caller. */
253 static void sunhv_enable_ms(struct uart_port *port)
257 /* port->lock is not held. */
258 static void sunhv_break_ctl(struct uart_port *port, int break_state)
264 spin_lock_irqsave(&port->lock, flags);
266 while (limit-- > 0) {
267 long status = hypervisor_con_putchar(CON_BREAK);
268 if (status == HV_EOK)
272 spin_unlock_irqrestore(&port->lock, flags);
276 /* port->lock is not held. */
277 static int sunhv_startup(struct uart_port *port)
282 /* port->lock is not held. */
283 static void sunhv_shutdown(struct uart_port *port)
287 /* port->lock is not held. */
288 static void sunhv_set_termios(struct uart_port *port, struct termios *termios,
291 unsigned int baud = uart_get_baud_rate(port, termios, old, 0, 4000000);
292 unsigned int quot = uart_get_divisor(port, baud);
293 unsigned int iflag, cflag;
296 spin_lock_irqsave(&port->lock, flags);
298 iflag = termios->c_iflag;
299 cflag = termios->c_cflag;
301 port->ignore_status_mask = 0;
303 port->ignore_status_mask |= IGNORE_BREAK;
304 if ((cflag & CREAD) == 0)
305 port->ignore_status_mask |= IGNORE_ALL;
308 uart_update_timeout(port, cflag,
309 (port->uartclk / (16 * quot)));
311 spin_unlock_irqrestore(&port->lock, flags);
314 static const char *sunhv_type(struct uart_port *port)
316 return "SUN4V HCONS";
319 static void sunhv_release_port(struct uart_port *port)
323 static int sunhv_request_port(struct uart_port *port)
328 static void sunhv_config_port(struct uart_port *port, int flags)
332 static int sunhv_verify_port(struct uart_port *port, struct serial_struct *ser)
337 static struct uart_ops sunhv_pops = {
338 .tx_empty = sunhv_tx_empty,
339 .set_mctrl = sunhv_set_mctrl,
340 .get_mctrl = sunhv_get_mctrl,
341 .stop_tx = sunhv_stop_tx,
342 .start_tx = sunhv_start_tx,
343 .send_xchar = sunhv_send_xchar,
344 .stop_rx = sunhv_stop_rx,
345 .enable_ms = sunhv_enable_ms,
346 .break_ctl = sunhv_break_ctl,
347 .startup = sunhv_startup,
348 .shutdown = sunhv_shutdown,
349 .set_termios = sunhv_set_termios,
351 .release_port = sunhv_release_port,
352 .request_port = sunhv_request_port,
353 .config_port = sunhv_config_port,
354 .verify_port = sunhv_verify_port,
357 static struct uart_driver sunhv_reg = {
358 .owner = THIS_MODULE,
359 .driver_name = "serial",
360 .devfs_name = "tts/",
365 static struct uart_port *sunhv_port;
367 static inline void sunhv_console_putchar(struct uart_port *port, char c)
372 spin_lock_irqsave(&port->lock, flags);
374 while (limit-- > 0) {
375 long status = hypervisor_con_putchar(c);
376 if (status == HV_EOK)
381 spin_unlock_irqrestore(&port->lock, flags);
384 static void sunhv_console_write(struct console *con, const char *s, unsigned n)
386 struct uart_port *port = sunhv_port;
389 for (i = 0; i < n; i++) {
391 sunhv_console_putchar(port, '\r');
392 sunhv_console_putchar(port, *s++);
396 static struct console sunhv_console = {
398 .write = sunhv_console_write,
399 .device = uart_console_device,
400 .flags = CON_PRINTBUFFER,
405 static inline struct console *SUNHV_CONSOLE(void)
407 if (con_is_present())
410 sunhv_console.index = 0;
412 return &sunhv_console;
415 static int __init hv_console_compatible(char *buf, int len)
420 if (!strcmp(buf, "qcn"))
423 this_len = strlen(buf) + 1;
432 static unsigned int __init get_interrupt(void)
434 const char *cons_str = "console";
435 const char *compat_str = "compatible";
436 int node = prom_getchild(sun4v_vdev_root);
440 node = prom_searchsiblings(node, cons_str);
444 len = prom_getproplen(node, compat_str);
445 if (len == 0 || len == -1)
448 err = prom_getproperty(node, compat_str, buf, 64);
452 if (!hv_console_compatible(buf, len))
455 /* Ok, the this is the OBP node for the sun4v hypervisor
456 * console device. Decode the interrupt.
458 return sun4v_vdev_device_interrupt(node);
461 static int __init sunhv_init(void)
463 struct uart_port *port;
466 if (tlb_type != hypervisor)
469 port = kmalloc(sizeof(struct uart_port), GFP_KERNEL);
473 memset(port, 0, sizeof(struct uart_port));
476 port->ops = &sunhv_pops;
477 port->type = PORT_SUNHV;
478 port->uartclk = ( 29491200 / 16 ); /* arbitrary */
480 /* Set this just to make uart_configure_port() happy. */
481 port->membase = (unsigned char __iomem *) __pa(port);
483 port->irq = get_interrupt();
489 sunhv_reg.minor = sunserial_current_minor;
492 ret = uart_register_driver(&sunhv_reg);
494 printk(KERN_ERR "SUNHV: uart_register_driver() failed %d\n",
501 sunserial_current_minor += 1;
503 sunhv_reg.cons = SUNHV_CONSOLE();
507 ret = uart_add_one_port(&sunhv_reg, port);
509 printk(KERN_ERR "SUNHV: uart_add_one_port() failed %d\n", ret);
510 sunserial_current_minor -= 1;
511 uart_unregister_driver(&sunhv_reg);
517 if (request_irq(port->irq, sunhv_interrupt,
518 SA_SHIRQ, "serial(sunhv)", port)) {
519 printk(KERN_ERR "sunhv: Cannot register IRQ\n");
520 uart_remove_one_port(&sunhv_reg, port);
521 sunserial_current_minor -= 1;
522 uart_unregister_driver(&sunhv_reg);
531 static void __exit sunhv_exit(void)
533 struct uart_port *port = sunhv_port;
537 free_irq(port->irq, port);
539 uart_remove_one_port(&sunhv_reg, port);
540 sunserial_current_minor -= 1;
542 uart_unregister_driver(&sunhv_reg);
548 module_init(sunhv_init);
549 module_exit(sunhv_exit);
551 MODULE_AUTHOR("David S. Miller");
552 MODULE_DESCRIPTION("SUN4V Hypervisor console driver")
553 MODULE_LICENSE("GPL");