2 * Copyright (C) 2001 Anton Blanchard <anton@au.ibm.com>, IBM
3 * Copyright (C) 2001 Paul Mackerras <paulus@au.ibm.com>, IBM
4 * Copyright (C) 2004 Benjamin Herrenschmidt <benh@kernel.crashing.org>, IBM Corp.
5 * Copyright (C) 2004 IBM Corporation
7 * Additional Author(s):
8 * Ryan S. Arnold <rsa@us.ibm.com>
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License as published by
12 * the Free Software Foundation; either version 2 of the License, or
13 * (at your option) any later version.
15 * This program is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 * GNU General Public License for more details.
20 * You should have received a copy of the GNU General Public License
21 * along with this program; if not, write to the Free Software
22 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
25 #include <linux/console.h>
26 #include <linux/cpumask.h>
27 #include <linux/init.h>
28 #include <linux/kbd_kern.h>
29 #include <linux/kernel.h>
30 #include <linux/kobject.h>
31 #include <linux/kthread.h>
32 #include <linux/list.h>
33 #include <linux/module.h>
34 #include <linux/major.h>
35 #include <linux/sysrq.h>
36 #include <linux/tty.h>
37 #include <linux/tty_flip.h>
38 #include <linux/sched.h>
39 #include <linux/spinlock.h>
40 #include <linux/delay.h>
41 #include <asm/uaccess.h>
42 #include <asm/hvconsole.h>
51 * Wait this long per iteration while trying to push buffered data to the
52 * hypervisor before allowing the tty to complete a close operation.
54 #define HVC_CLOSE_WAIT (HZ/100) /* 1/10 of a second */
57 * The Linux TTY code does not support dynamic addition of tty derived devices
58 * so we need to know how many tty devices we might need when space is allocated
59 * for the tty device. Since this driver supports hotplug of vty adapters we
60 * need to make sure we have enough allocated.
62 #define HVC_ALLOC_TTY_ADAPTERS 8
67 #define __ALIGNED__ __attribute__((__aligned__(8)))
69 static struct tty_driver *hvc_driver;
70 static struct task_struct *hvc_task;
72 /* Picks up late kicks after list walk but before schedule() */
73 static int hvc_kicked;
75 #ifdef CONFIG_MAGIC_SYSRQ
76 static int sysrq_pressed;
82 struct tty_struct *tty;
85 char outbuf[N_OUTBUF] __ALIGNED__;
90 struct list_head next;
91 struct kobject kobj; /* ref count & hvc_struct lifetime */
95 /* dynamic list of hvc_struct instances */
96 static struct list_head hvc_structs = LIST_HEAD_INIT(hvc_structs);
99 * Protect the list of hvc_struct instances from inserts and removals during
102 static DEFINE_SPINLOCK(hvc_structs_lock);
105 * This value is used to associate a tty->index value to a hvc_struct based
106 * upon order of exposure via hvc_probe().
108 static int hvc_count = -1;
111 * Do not call this function with either the hvc_strucst_lock or the hvc_struct
112 * lock held. If successful, this function increments the kobject reference
113 * count against the target hvc_struct so it should be released when finished.
115 struct hvc_struct *hvc_get_by_index(int index)
117 struct hvc_struct *hp;
120 spin_lock(&hvc_structs_lock);
122 list_for_each_entry(hp, &hvc_structs, next) {
123 spin_lock_irqsave(&hp->lock, flags);
124 if (hp->index == index) {
125 kobject_get(&hp->kobj);
126 spin_unlock_irqrestore(&hp->lock, flags);
127 spin_unlock(&hvc_structs_lock);
130 spin_unlock_irqrestore(&hp->lock, flags);
134 spin_unlock(&hvc_structs_lock);
140 * Initial console vtermnos for console API usage prior to full console
141 * initialization. Any vty adapter outside this range will not have usable
142 * console interfaces but can still be used as a tty device. This has to be
143 * static because kmalloc will not work during early console init.
145 static uint32_t vtermnos[MAX_NR_HVC_CONSOLES];
147 /* Used for accounting purposes */
148 static int num_vterms = 0;
151 * Console APIs, NOT TTY. These APIs are available immediately when
152 * hvc_console_setup() finds adapters.
155 void hvc_console_print(struct console *co, const char *b, unsigned count)
157 char c[16] __ALIGNED__;
158 unsigned i = 0, n = 0;
161 /* Console access attempt outside of acceptable console range. */
162 if (co->index >= MAX_NR_HVC_CONSOLES)
165 /* This console adapter was removed so it is not useable. */
166 if (vtermnos[co->index] < 0)
169 while (count > 0 || i > 0) {
170 if (count > 0 && i < sizeof(c)) {
171 if (b[n] == '\n' && !donecr) {
180 r = hvc_put_chars(vtermnos[co->index], c, i);
182 /* throw away chars on error */
193 static struct tty_driver *hvc_console_device(struct console *c, int *index)
199 static int __init hvc_console_setup(struct console *co, char *options)
204 struct console hvc_con_driver = {
206 .write = hvc_console_print,
207 .device = hvc_console_device,
208 .setup = hvc_console_setup,
209 .flags = CON_PRINTBUFFER,
213 /* Early console initialization. Preceeds driver initialization. */
214 static int __init hvc_console_init(void)
218 for (i=0; i<MAX_NR_HVC_CONSOLES; i++)
220 num_vterms = hvc_find_vtys();
221 register_console(&hvc_con_driver);
224 console_initcall(hvc_console_init);
227 * hvc_instantiate() is an early console discovery method which locates consoles
228 * prior to the vio subsystem discovering them. Hotplugged vty adapters do NOT
229 * get an hvc_instantiate() callback since the appear after early console init.
231 int hvc_instantiate(uint32_t vtermno, int index)
233 if (index < 0 || index >= MAX_NR_HVC_CONSOLES)
236 if (vtermnos[index] != -1)
239 vtermnos[index] = vtermno;
243 /* Wake the sleeping khvcd */
244 static void hvc_kick(void)
247 wake_up_process(hvc_task);
251 * NOTE: This API isn't used if the console adapter doesn't support interrupts.
252 * In this case the console is poll driven.
254 static irqreturn_t hvc_handle_interrupt(int irq, void *dev_instance, struct pt_regs *regs)
260 static void hvc_unthrottle(struct tty_struct *tty)
266 * The TTY interface won't be used until after the vio layer has exposed the vty
267 * adapter to the kernel.
269 static int hvc_open(struct tty_struct *tty, struct file * filp)
271 struct hvc_struct *hp;
275 struct kobject *kobjp;
277 /* Auto increments kobject reference if found. */
278 if (!(hp = hvc_get_by_index(tty->index))) {
279 printk(KERN_WARNING "hvc_console: tty open failed, no vty associated with tty.\n");
283 spin_lock_irqsave(&hp->lock, flags);
284 /* Check and then increment for fast path open. */
285 if (hp->count++ > 0) {
286 spin_unlock_irqrestore(&hp->lock, flags);
289 } /* else count == 0 */
291 tty->driver_data = hp;
293 /* Save for request_irq outside of spin_lock. */
296 hp->irq_requested = 1;
300 spin_unlock_irqrestore(&hp->lock, flags);
301 /* check error, fallback to non-irq */
303 rc = request_irq(irq, hvc_handle_interrupt, SA_INTERRUPT, "hvc_console", hp);
306 * If the request_irq() fails and we return an error. The tty layer
307 * will call hvc_close() after a failed open but we don't want to clean
308 * up there so we'll clean up here and clear out the previously set
309 * tty fields and return the kobject reference.
312 spin_lock_irqsave(&hp->lock, flags);
314 hp->irq_requested = 0;
315 spin_unlock_irqrestore(&hp->lock, flags);
316 tty->driver_data = NULL;
318 printk(KERN_ERR "hvc_open: request_irq failed with rc %d.\n", rc);
320 /* Force wakeup of the polling thread */
326 static void hvc_close(struct tty_struct *tty, struct file * filp)
328 struct hvc_struct *hp;
329 struct kobject *kobjp;
333 if (tty_hung_up_p(filp))
337 * No driver_data means that this close was issued after a failed
338 * hvc_open by the tty layer's release_dev() function and we can just
339 * exit cleanly because the kobject reference wasn't made.
341 if (!tty->driver_data)
344 hp = tty->driver_data;
345 spin_lock_irqsave(&hp->lock, flags);
348 if (--hp->count == 0) {
349 if (hp->irq_requested)
351 hp->irq_requested = 0;
353 /* We are done with the tty pointer now. */
355 spin_unlock_irqrestore(&hp->lock, flags);
358 * Chain calls chars_in_buffer() and returns immediately if
359 * there is no buffered data otherwise sleeps on a wait queue
360 * waking periodically to check chars_in_buffer().
362 tty_wait_until_sent(tty, HVC_CLOSE_WAIT);
369 printk(KERN_ERR "hvc_close %X: oops, count is %d\n",
370 hp->vtermno, hp->count);
371 spin_unlock_irqrestore(&hp->lock, flags);
377 static void hvc_hangup(struct tty_struct *tty)
379 struct hvc_struct *hp = tty->driver_data;
383 struct kobject *kobjp;
388 spin_lock_irqsave(&hp->lock, flags);
391 * The N_TTY line discipline has problems such that in a close vs
392 * open->hangup case this can be called after the final close so prevent
393 * that from happening for now.
395 if (hp->count <= 0) {
396 spin_unlock_irqrestore(&hp->lock, flags);
401 temp_open_count = hp->count;
405 if (hp->irq_requested)
406 /* Saved for use outside of spin_lock. */
408 hp->irq_requested = 0;
409 spin_unlock_irqrestore(&hp->lock, flags);
412 while(temp_open_count) {
419 * Push buffered characters whether they were just recently buffered or waiting
420 * on a blocked hypervisor. Call this function with hp->lock held.
422 static void hvc_push(struct hvc_struct *hp)
426 n = hvc_put_chars(hp->vtermno, hp->outbuf, hp->n_outbuf);
430 /* throw away output on error; this happens when
431 there is no session connected to the vterm. */
435 if (hp->n_outbuf > 0)
436 memmove(hp->outbuf, hp->outbuf + n, hp->n_outbuf);
441 static inline int __hvc_write_kernel(struct hvc_struct *hp,
442 const unsigned char *buf, int count)
445 int rsize, written = 0;
447 spin_lock_irqsave(&hp->lock, flags);
449 /* Push pending writes */
450 if (hp->n_outbuf > 0)
453 while (count > 0 && (rsize = N_OUTBUF - hp->n_outbuf) > 0) {
456 memcpy(hp->outbuf + hp->n_outbuf, buf, rsize);
459 hp->n_outbuf += rsize;
463 spin_unlock_irqrestore(&hp->lock, flags);
467 static int hvc_write(struct tty_struct *tty, const unsigned char *buf, int count)
469 struct hvc_struct *hp = tty->driver_data;
472 /* This write was probably executed during a tty close. */
479 written = __hvc_write_kernel(hp, buf, count);
482 * Racy, but harmless, kick thread if there is still pending data.
483 * There really is nothing wrong with kicking the thread, even if there
484 * is no buffered data.
493 * This is actually a contract between the driver and the tty layer outlining
494 * how much write room the driver can guarentee will be sent OR BUFFERED. This
495 * driver MUST honor the return value.
497 static int hvc_write_room(struct tty_struct *tty)
499 struct hvc_struct *hp = tty->driver_data;
504 return N_OUTBUF - hp->n_outbuf;
507 static int hvc_chars_in_buffer(struct tty_struct *tty)
509 struct hvc_struct *hp = tty->driver_data;
516 #define HVC_POLL_READ 0x00000001
517 #define HVC_POLL_WRITE 0x00000002
518 #define HVC_POLL_QUICK 0x00000004
520 static int hvc_poll(struct hvc_struct *hp)
522 struct tty_struct *tty;
523 int i, n, poll_mask = 0;
524 char buf[N_INBUF] __ALIGNED__;
528 spin_lock_irqsave(&hp->lock, flags);
530 /* Push pending writes */
531 if (hp->n_outbuf > 0)
533 /* Reschedule us if still some write pending */
534 if (hp->n_outbuf > 0)
535 poll_mask |= HVC_POLL_WRITE;
537 /* No tty attached, just skip */
542 /* Now check if we can get data (are we throttled ?) */
543 if (test_bit(TTY_THROTTLED, &tty->flags))
546 /* If we aren't interrupt driven and aren't throttled, we always
547 * request a reschedule
549 if (hp->irq == NO_IRQ)
550 poll_mask |= HVC_POLL_READ;
552 /* Read data if any */
555 if (count > (TTY_FLIPBUF_SIZE - tty->flip.count))
556 count = TTY_FLIPBUF_SIZE - tty->flip.count;
558 /* If flip is full, just reschedule a later read */
560 poll_mask |= HVC_POLL_READ;
564 n = hvc_get_chars(hp->vtermno, buf, count);
566 /* Hangup the tty when disconnected from host */
568 spin_unlock_irqrestore(&hp->lock, flags);
570 spin_lock_irqsave(&hp->lock, flags);
574 for (i = 0; i < n; ++i) {
575 #ifdef CONFIG_MAGIC_SYSRQ
576 /* Handle the SysRq Hack */
577 if (buf[i] == '\x0f') { /* ^O -- should support a sequence */
580 } else if (sysrq_pressed) {
581 handle_sysrq(buf[i], NULL, tty);
585 #endif /* CONFIG_MAGIC_SYSRQ */
586 tty_insert_flip_char(tty, buf[i], 0);
590 tty_schedule_flip(tty);
593 * Account for the total amount read in one loop, and if above
594 * 64 bytes, we do a quick schedule loop to let the tty grok the
595 * data and eventually throttle us.
598 if (read_total >= 64) {
599 poll_mask |= HVC_POLL_QUICK;
604 /* Wakeup write queue if necessary */
610 spin_unlock_irqrestore(&hp->lock, flags);
615 #if defined(CONFIG_XMON) && defined(CONFIG_SMP)
616 extern cpumask_t cpus_in_xmon;
618 static const cpumask_t cpus_in_xmon = CPU_MASK_NONE;
622 * This kthread is either polling or interrupt driven. This is determined by
623 * calling hvc_poll() who determines whether a console adapter support
626 int khvcd(void *unused)
629 struct hvc_struct *hp;
631 __set_current_state(TASK_RUNNING);
636 if (cpus_empty(cpus_in_xmon)) {
637 spin_lock(&hvc_structs_lock);
638 list_for_each_entry(hp, &hvc_structs, next) {
639 /*hp = list_entry(node, struct hvc_struct, * next); */
640 poll_mask |= hvc_poll(hp);
642 spin_unlock(&hvc_structs_lock);
644 poll_mask |= HVC_POLL_READ;
647 if (poll_mask & HVC_POLL_QUICK) {
651 set_current_state(TASK_INTERRUPTIBLE);
656 msleep_interruptible(TIMEOUT);
658 __set_current_state(TASK_RUNNING);
659 } while (!kthread_should_stop());
664 static struct tty_operations hvc_ops = {
668 .hangup = hvc_hangup,
669 .unthrottle = hvc_unthrottle,
670 .write_room = hvc_write_room,
671 .chars_in_buffer = hvc_chars_in_buffer,
674 /* callback when the kboject ref count reaches zero. */
675 static void destroy_hvc_struct(struct kobject *kobj)
677 struct hvc_struct *hp = container_of(kobj, struct hvc_struct, kobj);
680 spin_lock(&hvc_structs_lock);
682 spin_lock_irqsave(&hp->lock, flags);
683 list_del(&(hp->next));
684 spin_unlock_irqrestore(&hp->lock, flags);
686 spin_unlock(&hvc_structs_lock);
691 static struct kobj_type hvc_kobj_type = {
692 .release = destroy_hvc_struct,
695 static int __devinit hvc_probe(
697 const struct vio_device_id *id)
699 struct hvc_struct *hp;
701 /* probed with invalid parameters. */
705 hp = kmalloc(sizeof(*hp), GFP_KERNEL);
709 memset(hp, 0x00, sizeof(*hp));
710 hp->vtermno = dev->unit_address;
712 hp->vdev->dev.driver_data = hp;
715 kobject_init(&hp->kobj);
716 hp->kobj.ktype = &hvc_kobj_type;
718 spin_lock_init(&hp->lock);
719 spin_lock(&hvc_structs_lock);
720 hp->index = ++hvc_count;
721 list_add_tail(&(hp->next), &hvc_structs);
722 spin_unlock(&hvc_structs_lock);
727 static int __devexit hvc_remove(struct vio_dev *dev)
729 struct hvc_struct *hp = dev->dev.driver_data;
731 struct kobject *kobjp;
732 struct tty_struct *tty;
734 spin_lock_irqsave(&hp->lock, flags);
738 if (hp->index < MAX_NR_HVC_CONSOLES)
739 vtermnos[hp->index] = -1;
741 /* Don't whack hp->irq because tty_hangup() will need to free the irq. */
743 spin_unlock_irqrestore(&hp->lock, flags);
746 * We 'put' the instance that was grabbed when the kobject instance
747 * was intialized using kobject_init(). Let the last holder of this
748 * kobject cause it to be removed, which will probably be the tty_hangup
754 * This function call will auto chain call hvc_hangup. The tty should
755 * always be valid at this time unless a simultaneous tty close already
756 * cleaned up the hvc_struct.
763 char hvc_driver_name[] = "hvc_console";
765 static struct vio_device_id hvc_driver_table[] __devinitdata= {
766 {"serial", "hvterm1"},
769 MODULE_DEVICE_TABLE(vio, hvc_driver_table);
771 static struct vio_driver hvc_vio_driver = {
772 .name = hvc_driver_name,
773 .id_table = hvc_driver_table,
775 .remove = hvc_remove,
778 /* Driver initialization. Follow console initialization. This is where the TTY
779 * interfaces start to become available. */
780 int __init hvc_init(void)
784 /* We need more than num_vterms adapters due to hotplug additions. */
785 hvc_driver = alloc_tty_driver(HVC_ALLOC_TTY_ADAPTERS);
786 /* hvc_driver = alloc_tty_driver(num_vterms); */
790 hvc_driver->owner = THIS_MODULE;
791 hvc_driver->devfs_name = "hvc/";
792 hvc_driver->driver_name = "hvc";
793 hvc_driver->name = "hvc";
794 hvc_driver->major = HVC_MAJOR;
795 hvc_driver->minor_start = HVC_MINOR;
796 hvc_driver->type = TTY_DRIVER_TYPE_SYSTEM;
797 hvc_driver->init_termios = tty_std_termios;
798 hvc_driver->flags = TTY_DRIVER_REAL_RAW;
799 tty_set_operations(hvc_driver, &hvc_ops);
801 if (tty_register_driver(hvc_driver))
802 panic("Couldn't register hvc console driver\n");
804 /* Always start the kthread because there can be hotplug vty adapters
806 hvc_task = kthread_run(khvcd, NULL, "khvcd");
807 if (IS_ERR(hvc_task)) {
808 panic("Couldn't create kthread for console.\n");
809 put_tty_driver(hvc_driver);
813 /* Register as a vio device to receive callbacks */
814 rc = vio_register_driver(&hvc_vio_driver);
818 module_init(hvc_init);
820 /* This isn't particularily necessary due to this being a console driver but it
821 * is nice to be thorough */
822 static void __exit hvc_exit(void)
824 kthread_stop(hvc_task);
826 vio_unregister_driver(&hvc_vio_driver);
827 tty_unregister_driver(hvc_driver);
828 /* return tty_struct instances allocated in hvc_init(). */
829 put_tty_driver(hvc_driver);
831 module_exit(hvc_exit);