diff options
Diffstat (limited to 'drivers/s390/char/sclp_con.c')
| -rw-r--r-- | drivers/s390/char/sclp_con.c | 139 |
1 files changed, 99 insertions, 40 deletions
diff --git a/drivers/s390/char/sclp_con.c b/drivers/s390/char/sclp_con.c index 9a25c4bd1421..336811a77672 100644 --- a/drivers/s390/char/sclp_con.c +++ b/drivers/s390/char/sclp_con.c @@ -1,11 +1,9 @@ /* - * drivers/s390/char/sclp_con.c - * SCLP line mode console driver + * SCLP line mode console driver * - * S390 version - * Copyright (C) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation - * Author(s): Martin Peschke <mpeschke@de.ibm.com> - * Martin Schwidefsky <schwidefsky@de.ibm.com> + * Copyright IBM Corp. 1999, 2009 + * Author(s): Martin Peschke <mpeschke@de.ibm.com> + * Martin Schwidefsky <schwidefsky@de.ibm.com> */ #include <linux/kmod.h> @@ -32,13 +30,14 @@ static spinlock_t sclp_con_lock; static struct list_head sclp_con_pages; /* List of full struct sclp_buffer structures ready for output */ static struct list_head sclp_con_outqueue; -/* Counter how many buffers are emitted (max 1) and how many */ -/* are on the output queue. */ -static int sclp_con_buffer_count; /* Pointer to current console buffer */ static struct sclp_buffer *sclp_conbuf; /* Timer for delayed output of console messages */ static struct timer_list sclp_con_timer; +/* Suspend mode flag */ +static int sclp_con_suspended; +/* Flag that output queue is currently running */ +static int sclp_con_queue_running; /* Output format for console messages */ static unsigned short sclp_con_columns; @@ -53,42 +52,71 @@ sclp_conbuf_callback(struct sclp_buffer *buffer, int rc) do { page = sclp_unmake_buffer(buffer); spin_lock_irqsave(&sclp_con_lock, flags); + /* Remove buffer from outqueue */ list_del(&buffer->list); - sclp_con_buffer_count--; list_add_tail((struct list_head *) page, &sclp_con_pages); + /* Check if there is a pending buffer on the out queue. */ buffer = NULL; if (!list_empty(&sclp_con_outqueue)) - buffer = list_entry(sclp_con_outqueue.next, - struct sclp_buffer, list); + buffer = list_first_entry(&sclp_con_outqueue, + struct sclp_buffer, list); + if (!buffer || sclp_con_suspended) { + sclp_con_queue_running = 0; + spin_unlock_irqrestore(&sclp_con_lock, flags); + break; + } spin_unlock_irqrestore(&sclp_con_lock, flags); - } while (buffer && sclp_emit_buffer(buffer, sclp_conbuf_callback)); + } while (sclp_emit_buffer(buffer, sclp_conbuf_callback)); } -static void -sclp_conbuf_emit(void) +/* + * Finalize and emit first pending buffer. + */ +static void sclp_conbuf_emit(void) { struct sclp_buffer* buffer; unsigned long flags; - int count; int rc; spin_lock_irqsave(&sclp_con_lock, flags); - buffer = sclp_conbuf; + if (sclp_conbuf) + list_add_tail(&sclp_conbuf->list, &sclp_con_outqueue); sclp_conbuf = NULL; - if (buffer == NULL) { - spin_unlock_irqrestore(&sclp_con_lock, flags); - return; - } - list_add_tail(&buffer->list, &sclp_con_outqueue); - count = sclp_con_buffer_count++; + if (sclp_con_queue_running || sclp_con_suspended) + goto out_unlock; + if (list_empty(&sclp_con_outqueue)) + goto out_unlock; + buffer = list_first_entry(&sclp_con_outqueue, struct sclp_buffer, + list); + sclp_con_queue_running = 1; spin_unlock_irqrestore(&sclp_con_lock, flags); - if (count) - return; + rc = sclp_emit_buffer(buffer, sclp_conbuf_callback); if (rc) sclp_conbuf_callback(buffer, rc); + return; +out_unlock: + spin_unlock_irqrestore(&sclp_con_lock, flags); +} + +/* + * Wait until out queue is empty + */ +static void sclp_console_sync_queue(void) +{ + unsigned long flags; + + spin_lock_irqsave(&sclp_con_lock, flags); + if (timer_pending(&sclp_con_timer)) + del_timer_sync(&sclp_con_timer); + while (sclp_con_queue_running) { + spin_unlock_irqrestore(&sclp_con_lock, flags); + sclp_sync_wait(); + spin_lock_irqsave(&sclp_con_lock, flags); + } + spin_unlock_irqrestore(&sclp_con_lock, flags); } /* @@ -123,6 +151,8 @@ sclp_console_write(struct console *console, const char *message, /* make sure we have a console output buffer */ if (sclp_conbuf == NULL) { while (list_empty(&sclp_con_pages)) { + if (sclp_con_suspended) + goto out; spin_unlock_irqrestore(&sclp_con_lock, flags); sclp_sync_wait(); spin_lock_irqsave(&sclp_con_lock, flags); @@ -157,6 +187,7 @@ sclp_console_write(struct console *console, const char *message, sclp_con_timer.expires = jiffies + HZ/10; add_timer(&sclp_con_timer); } +out: spin_unlock_irqrestore(&sclp_con_lock, flags); } @@ -168,30 +199,43 @@ sclp_console_device(struct console *c, int *index) } /* - * This routine is called from panic when the kernel - * is going to give up. We have to make sure that all buffers - * will be flushed to the SCLP. + * Make sure that all buffers will be flushed to the SCLP. */ static void sclp_console_flush(void) { + sclp_conbuf_emit(); + sclp_console_sync_queue(); +} + +/* + * Resume console: If there are cached messages, emit them. + */ +static void sclp_console_resume(void) +{ unsigned long flags; + spin_lock_irqsave(&sclp_con_lock, flags); + sclp_con_suspended = 0; + spin_unlock_irqrestore(&sclp_con_lock, flags); sclp_conbuf_emit(); +} + +/* + * Suspend console: Set suspend flag and flush console + */ +static void sclp_console_suspend(void) +{ + unsigned long flags; + spin_lock_irqsave(&sclp_con_lock, flags); - if (timer_pending(&sclp_con_timer)) - del_timer(&sclp_con_timer); - while (sclp_con_buffer_count > 0) { - spin_unlock_irqrestore(&sclp_con_lock, flags); - sclp_sync_wait(); - spin_lock_irqsave(&sclp_con_lock, flags); - } + sclp_con_suspended = 1; spin_unlock_irqrestore(&sclp_con_lock, flags); + sclp_console_flush(); } -static int -sclp_console_notify(struct notifier_block *self, - unsigned long event, void *data) +static int sclp_console_notify(struct notifier_block *self, + unsigned long event, void *data) { sclp_console_flush(); return NOTIFY_OK; @@ -199,7 +243,7 @@ sclp_console_notify(struct notifier_block *self, static struct notifier_block on_panic_nb = { .notifier_call = sclp_console_notify, - .priority = 1, + .priority = SCLP_PANIC_PRIO_CLIENT, }; static struct notifier_block on_reboot_nb = { @@ -221,6 +265,22 @@ static struct console sclp_console = }; /* + * This function is called for SCLP suspend and resume events. + */ +void sclp_console_pm_event(enum sclp_pm_event sclp_pm_event) +{ + switch (sclp_pm_event) { + case SCLP_PM_EVENT_FREEZE: + sclp_console_suspend(); + break; + case SCLP_PM_EVENT_RESTORE: + case SCLP_PM_EVENT_THAW: + sclp_console_resume(); + break; + } +} + +/* * called by console_init() in drivers/char/tty_io.c at boot-time. */ static int __init @@ -243,7 +303,6 @@ sclp_console_init(void) } INIT_LIST_HEAD(&sclp_con_outqueue); spin_lock_init(&sclp_con_lock); - sclp_con_buffer_count = 0; sclp_conbuf = NULL; init_timer(&sclp_con_timer); |