diff options
Diffstat (limited to 'drivers/s390/char/sclp_con.c')
| -rw-r--r-- | drivers/s390/char/sclp_con.c | 197 |
1 files changed, 151 insertions, 46 deletions
diff --git a/drivers/s390/char/sclp_con.c b/drivers/s390/char/sclp_con.c index ead1043d788..5880def98fc 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> @@ -13,15 +11,15 @@ #include <linux/init.h> #include <linux/timer.h> #include <linux/jiffies.h> -#include <linux/bootmem.h> +#include <linux/termios.h> #include <linux/err.h> +#include <linux/reboot.h> +#include <linux/gfp.h> #include "sclp.h" #include "sclp_rw.h" #include "sclp_tty.h" -#define SCLP_CON_PRINT_HEADER "sclp console driver: " - #define sclp_console_major 4 /* TTYAUX_MAJOR */ #define sclp_console_minor 64 #define sclp_console_name "ttyS" @@ -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(&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); } /* @@ -102,6 +130,31 @@ sclp_console_timeout(unsigned long data) } /* + * Drop oldest console buffer if sclp_con_drop is set + */ +static int +sclp_console_drop_buffer(void) +{ + struct list_head *list; + struct sclp_buffer *buffer; + void *page; + + if (!sclp_console_drop) + return 0; + list = sclp_con_outqueue.next; + if (sclp_con_queue_running) + /* The first element is in I/O */ + list = list->next; + if (list == &sclp_con_outqueue) + return 0; + list_del(list); + buffer = list_entry(list, struct sclp_buffer, list); + page = sclp_unmake_buffer(buffer); + list_add_tail((struct list_head *) page, &sclp_con_pages); + return 1; +} + +/* * Writes the given message to S390 system console */ static void @@ -122,7 +175,13 @@ sclp_console_write(struct console *console, const char *message, do { /* make sure we have a console output buffer */ if (sclp_conbuf == NULL) { + if (list_empty(&sclp_con_pages)) + sclp_console_full++; while (list_empty(&sclp_con_pages)) { + if (sclp_con_suspended) + goto out; + if (sclp_console_drop_buffer()) + break; spin_unlock_irqrestore(&sclp_con_lock, flags); sclp_sync_wait(); spin_lock_irqsave(&sclp_con_lock, flags); @@ -157,6 +216,7 @@ 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); } @@ -168,27 +228,58 @@ 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_unblank(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) +{ + sclp_console_flush(); + return NOTIFY_OK; +} + +static struct notifier_block on_panic_nb = { + .notifier_call = sclp_console_notify, + .priority = SCLP_PANIC_PRIO_CLIENT, +}; + +static struct notifier_block on_reboot_nb = { + .notifier_call = sclp_console_notify, + .priority = 1, +}; + /* * used to register the SCLP console to the kernel and to * give printk necessary information @@ -198,12 +289,27 @@ static struct console sclp_console = .name = sclp_console_name, .write = sclp_console_write, .device = sclp_console_device, - .unblank = sclp_console_unblank, .flags = CON_PRINTBUFFER, .index = 0 /* ttyS0 */ }; /* + * 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 @@ -220,15 +326,12 @@ sclp_console_init(void) return rc; /* Allocate pages for output buffering */ INIT_LIST_HEAD(&sclp_con_pages); - for (i = 0; i < MAX_CONSOLE_PAGES; i++) { - page = alloc_bootmem_low_pages(PAGE_SIZE); - if (page == NULL) - return -ENOMEM; - list_add_tail((struct list_head *) page, &sclp_con_pages); + for (i = 0; i < sclp_console_pages; i++) { + page = (void *) get_zeroed_page(GFP_KERNEL | GFP_DMA); + list_add_tail(page, &sclp_con_pages); } 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); @@ -244,6 +347,8 @@ sclp_console_init(void) sclp_con_width_htab = 8; /* enable printk-access to this driver */ + atomic_notifier_chain_register(&panic_notifier_list, &on_panic_nb); + register_reboot_notifier(&on_reboot_nb); register_console(&sclp_console); return 0; } |