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>
26 #if defined(CONFIG_MAGIC_SYSRQ)
30 #include <linux/serial_core.h>
34 #define CON_BREAK ((long)-1)
35 #define CON_HUP ((long)-2)
37 static inline long hypervisor_con_getchar(long *status)
39 register unsigned long func asm("%o5");
40 register unsigned long arg0 asm("%o0");
41 register unsigned long arg1 asm("%o1");
43 func = HV_FAST_CONS_GETCHAR;
46 __asm__ __volatile__("ta %6"
47 : "=&r" (func), "=&r" (arg0), "=&r" (arg1)
48 : "0" (func), "1" (arg0), "2" (arg1),
56 static inline long hypervisor_con_putchar(long ch)
58 register unsigned long func asm("%o5");
59 register unsigned long arg0 asm("%o0");
61 func = HV_FAST_CONS_PUTCHAR;
63 __asm__ __volatile__("ta %4"
64 : "=&r" (func), "=&r" (arg0)
65 : "0" (func), "1" (arg0), "i" (HV_FAST_TRAP));
70 #define IGNORE_BREAK 0x1
71 #define IGNORE_ALL 0x2
73 static int hung_up = 0;
75 static struct tty_struct *receive_chars(struct uart_port *port, struct pt_regs *regs)
77 struct tty_struct *tty = NULL;
78 int saw_console_brk = 0;
81 if (port->info != NULL) /* Unopened serial console */
82 tty = port->info->tty;
86 long c = hypervisor_con_getchar(&status);
89 if (status == HV_EWOULDBLOCK)
99 uart_handle_dcd_change(port, 0);
100 } else if (hung_up) {
102 uart_handle_dcd_change(port, 1);
106 uart_handle_sysrq_char(port, c, regs);
112 if (c == CON_BREAK) {
114 if (uart_handle_break(port))
119 if (uart_handle_sysrq_char(port, c, regs))
122 if ((port->ignore_status_mask & IGNORE_ALL) ||
123 ((port->ignore_status_mask & IGNORE_BREAK) &&
127 tty_insert_flip_char(tty, c, flag);
136 static void transmit_chars(struct uart_port *port)
138 struct circ_buf *xmit = &port->info->xmit;
140 if (uart_circ_empty(xmit) || uart_tx_stopped(port))
143 while (!uart_circ_empty(xmit)) {
144 long status = hypervisor_con_putchar(xmit->buf[xmit->tail]);
146 if (status != HV_EOK)
149 xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
153 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
154 uart_write_wakeup(port);
157 static irqreturn_t sunhv_interrupt(int irq, void *dev_id, struct pt_regs *regs)
159 struct uart_port *port = dev_id;
160 struct tty_struct *tty;
163 spin_lock_irqsave(&port->lock, flags);
164 tty = receive_chars(port, regs);
165 transmit_chars(port);
166 spin_unlock_irqrestore(&port->lock, flags);
169 tty_flip_buffer_push(tty);
174 /* port->lock is not held. */
175 static unsigned int sunhv_tx_empty(struct uart_port *port)
177 /* Transmitter is always empty for us. If the circ buffer
178 * is non-empty or there is an x_char pending, our caller
179 * will do the right thing and ignore what we return here.
184 /* port->lock held by caller. */
185 static void sunhv_set_mctrl(struct uart_port *port, unsigned int mctrl)
190 /* port->lock is held by caller and interrupts are disabled. */
191 static unsigned int sunhv_get_mctrl(struct uart_port *port)
193 return TIOCM_DSR | TIOCM_CAR | TIOCM_CTS;
196 /* port->lock held by caller. */
197 static void sunhv_stop_tx(struct uart_port *port)
202 /* port->lock held by caller. */
203 static void sunhv_start_tx(struct uart_port *port)
205 struct circ_buf *xmit = &port->info->xmit;
208 spin_lock_irqsave(&port->lock, flags);
210 while (!uart_circ_empty(xmit)) {
211 long status = hypervisor_con_putchar(xmit->buf[xmit->tail]);
213 if (status != HV_EOK)
216 xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
220 spin_unlock_irqrestore(&port->lock, flags);
223 /* port->lock is not held. */
224 static void sunhv_send_xchar(struct uart_port *port, char ch)
229 spin_lock_irqsave(&port->lock, flags);
231 while (limit-- > 0) {
232 long status = hypervisor_con_putchar(ch);
233 if (status == HV_EOK)
237 spin_unlock_irqrestore(&port->lock, flags);
240 /* port->lock held by caller. */
241 static void sunhv_stop_rx(struct uart_port *port)
245 /* port->lock held by caller. */
246 static void sunhv_enable_ms(struct uart_port *port)
250 /* port->lock is not held. */
251 static void sunhv_break_ctl(struct uart_port *port, int break_state)
257 spin_lock_irqsave(&port->lock, flags);
259 while (limit-- > 0) {
260 long status = hypervisor_con_putchar(CON_BREAK);
261 if (status == HV_EOK)
265 spin_unlock_irqrestore(&port->lock, flags);
269 /* port->lock is not held. */
270 static int sunhv_startup(struct uart_port *port)
275 /* port->lock is not held. */
276 static void sunhv_shutdown(struct uart_port *port)
280 /* port->lock is not held. */
281 static void sunhv_set_termios(struct uart_port *port, struct termios *termios,
284 unsigned int baud = uart_get_baud_rate(port, termios, old, 0, 4000000);
285 unsigned int quot = uart_get_divisor(port, baud);
286 unsigned int iflag, cflag;
289 spin_lock_irqsave(&port->lock, flags);
291 iflag = termios->c_iflag;
292 cflag = termios->c_cflag;
294 port->ignore_status_mask = 0;
296 port->ignore_status_mask |= IGNORE_BREAK;
297 if ((cflag & CREAD) == 0)
298 port->ignore_status_mask |= IGNORE_ALL;
301 uart_update_timeout(port, cflag,
302 (port->uartclk / (16 * quot)));
304 spin_unlock_irqrestore(&port->lock, flags);
307 static const char *sunhv_type(struct uart_port *port)
309 return "SUN4V HCONS";
312 static void sunhv_release_port(struct uart_port *port)
316 static int sunhv_request_port(struct uart_port *port)
321 static void sunhv_config_port(struct uart_port *port, int flags)
325 static int sunhv_verify_port(struct uart_port *port, struct serial_struct *ser)
330 static struct uart_ops sunhv_pops = {
331 .tx_empty = sunhv_tx_empty,
332 .set_mctrl = sunhv_set_mctrl,
333 .get_mctrl = sunhv_get_mctrl,
334 .stop_tx = sunhv_stop_tx,
335 .start_tx = sunhv_start_tx,
336 .send_xchar = sunhv_send_xchar,
337 .stop_rx = sunhv_stop_rx,
338 .enable_ms = sunhv_enable_ms,
339 .break_ctl = sunhv_break_ctl,
340 .startup = sunhv_startup,
341 .shutdown = sunhv_shutdown,
342 .set_termios = sunhv_set_termios,
344 .release_port = sunhv_release_port,
345 .request_port = sunhv_request_port,
346 .config_port = sunhv_config_port,
347 .verify_port = sunhv_verify_port,
350 static struct uart_driver sunhv_reg = {
351 .owner = THIS_MODULE,
352 .driver_name = "serial",
353 .devfs_name = "tts/",
358 static struct uart_port *sunhv_port;
360 static inline void sunhv_console_putchar(struct uart_port *port, char c)
365 spin_lock_irqsave(&port->lock, flags);
367 while (limit-- > 0) {
368 long status = hypervisor_con_putchar(c);
369 if (status == HV_EOK)
373 spin_unlock_irqrestore(&port->lock, flags);
376 static void sunhv_console_write(struct console *con, const char *s, unsigned n)
378 struct uart_port *port = sunhv_port;
381 for (i = 0; i < n; i++) {
383 sunhv_console_putchar(port, '\r');
384 sunhv_console_putchar(port, *s++);
388 static int sunhv_console_setup(struct console *con, char *options)
393 static struct console sunhv_console = {
395 .write = sunhv_console_write,
396 .device = uart_console_device,
397 .setup = sunhv_console_setup,
398 .flags = CON_PRINTBUFFER,
403 static void __init sunhv_console_init(void)
405 if (con_is_present())
408 sunhv_console.index = 0;
409 register_console(&sunhv_console);
412 static int __init hv_console_compatible(char *buf, int len)
417 if (!strcmp(buf, "qcn"))
420 this_len = strlen(buf) + 1;
429 static unsigned int __init get_interrupt(void)
431 const char *cons_str = "console";
432 const char *compat_str = "compatible";
433 int node = prom_getchild(sun4v_vdev_root);
438 node = prom_searchsiblings(node, cons_str);
442 len = prom_getproplen(node, compat_str);
443 if (len == 0 || len == -1)
446 err = prom_getproperty(node, compat_str, buf, 64);
450 if (!hv_console_compatible(buf, len))
453 /* Ok, the this is the OBP node for the sun4v hypervisor
454 * console device. Decode the interrupt.
456 err = prom_getproperty(node, "interrupts",
457 (char *) &irq, sizeof(irq));
461 return sun4v_build_irq(sun4v_vdev_devhandle, irq, 4, 0);
464 static u32 sunhv_irq;
466 static int __init sunhv_init(void)
468 struct uart_port *port;
471 if (tlb_type != hypervisor)
474 sunhv_irq = get_interrupt();
478 port = kmalloc(sizeof(struct uart_port), GFP_KERNEL);
483 port->ops = &sunhv_pops;
484 port->type = PORT_SUNHV;
485 port->uartclk = ( 29491200 / 16 ); /* arbitrary */
487 if (request_irq(sunhv_irq, sunhv_interrupt,
488 SA_SHIRQ, "serial(sunhv)", port)) {
489 printk("sunhv: Cannot get IRQ %x\n", sunhv_irq);
494 printk("SUNHV: SUN4V virtual console, IRQ[%08x]\n",
497 sunhv_reg.minor = sunserial_current_minor;
499 sunhv_reg.cons = &sunhv_console;
501 ret = uart_register_driver(&sunhv_reg);
503 free_irq(sunhv_irq, up);
511 sunserial_current_minor += 1;
513 sunhv_console_init();
515 uart_add_one_port(&sunhv_reg, port);
520 static void __exit sunhv_exit(void)
522 struct uart_port *port = sunhv_port;
526 uart_remove_one_port(&sunhv_reg, port);
527 free_irq(sunhv_irq, port);
529 sunserial_current_minor -= 1;
531 uart_unregister_driver(&sunhv_reg);
537 module_init(sunhv_init);
538 module_exit(sunhv_exit);
540 MODULE_AUTHOR("David S. Miller");
541 MODULE_DESCRIPTION("SUN4V Hypervisor console driver")
542 MODULE_LICENSE("GPL");