X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=drivers%2Fs390%2Fchar%2Fsclp_vt220.c;h=a839aa531d7c0f011cbe6e135ce3bac897333d7e;hb=3ecdb9acf343bbcf2bb2c287dc524ab709cfad7e;hp=ed507594e62ba0adf12fde30a1ecd23a91509180;hpb=d1e23375bf5d1079cd54a1c6bc8592c42061f1e1;p=safe%2Fjmp%2Flinux-2.6 diff --git a/drivers/s390/char/sclp_vt220.c b/drivers/s390/char/sclp_vt220.c index ed50759..a839aa5 100644 --- a/drivers/s390/char/sclp_vt220.c +++ b/drivers/s390/char/sclp_vt220.c @@ -24,10 +24,11 @@ #include #include #include +#include + #include #include "sclp.h" -#define SCLP_VT220_PRINT_HEADER "sclp vt220 tty driver: " #define SCLP_VT220_MAJOR TTY_MAJOR #define SCLP_VT220_MINOR 65 #define SCLP_VT220_DRIVER_NAME "sclp_vt220" @@ -71,9 +72,6 @@ static struct list_head sclp_vt220_outqueue; /* Number of requests in outqueue */ static int sclp_vt220_outqueue_count; -/* Wait queue used to delay write requests while we've run out of buffers */ -static wait_queue_head_t sclp_vt220_waitq; - /* Timer used for delaying write requests to merge subsequent messages into * a single buffer */ static struct timer_list sclp_vt220_timer; @@ -85,8 +83,8 @@ static struct sclp_vt220_request *sclp_vt220_current_request; /* Number of characters in current request buffer */ static int sclp_vt220_buffered_chars; -/* Flag indicating whether this driver has already been initialized */ -static int sclp_vt220_initialized = 0; +/* Counter controlling core driver initialization. */ +static int __initdata sclp_vt220_init_count; /* Flag indicating that sclp_vt220_current_request should really * have been already queued but wasn't because the SCLP was processing @@ -133,7 +131,6 @@ sclp_vt220_process_queue(struct sclp_vt220_request *request) } while (request && __sclp_vt220_emit(request)); if (request == NULL && sclp_vt220_flush_later) sclp_vt220_emit_current(); - wake_up(&sclp_vt220_waitq); /* Check if the tty needs a wake up call */ if (sclp_vt220_tty != NULL) { tty_wakeup(sclp_vt220_tty); @@ -383,7 +380,7 @@ sclp_vt220_timeout(unsigned long data) */ static int __sclp_vt220_write(const unsigned char *buf, int count, int do_schedule, - int convertlf, int may_schedule) + int convertlf, int may_fail) { unsigned long flags; void *page; @@ -395,15 +392,14 @@ __sclp_vt220_write(const unsigned char *buf, int count, int do_schedule, overall_written = 0; spin_lock_irqsave(&sclp_vt220_lock, flags); do { - /* Create a sclp output buffer if none exists yet */ + /* Create an sclp output buffer if none exists yet */ if (sclp_vt220_current_request == NULL) { while (list_empty(&sclp_vt220_empty)) { spin_unlock_irqrestore(&sclp_vt220_lock, flags); - if (in_interrupt() || !may_schedule) - sclp_sync_wait(); + if (may_fail) + goto out; else - wait_event(sclp_vt220_waitq, - !list_empty(&sclp_vt220_empty)); + sclp_sync_wait(); spin_lock_irqsave(&sclp_vt220_lock, flags); } page = (void *) sclp_vt220_empty.next; @@ -437,6 +433,7 @@ __sclp_vt220_write(const unsigned char *buf, int count, int do_schedule, add_timer(&sclp_vt220_timer); } spin_unlock_irqrestore(&sclp_vt220_lock, flags); +out: return overall_written; } @@ -520,15 +517,11 @@ sclp_vt220_close(struct tty_struct *tty, struct file *filp) * character to the tty device. If the kernel uses this routine, * it must call the flush_chars() routine (if defined) when it is * done stuffing characters into the driver. - * - * NOTE: include/linux/tty_driver.h specifies that a character should be - * ignored if there is no room in the queue. This driver implements a different - * semantic in that it will block when there is no more room left. */ -static void +static int sclp_vt220_put_char(struct tty_struct *tty, unsigned char ch) { - __sclp_vt220_write(&ch, 1, 0, 0, 1); + return __sclp_vt220_write(&ch, 1, 0, 0, 1); } /* @@ -590,23 +583,6 @@ sclp_vt220_chars_in_buffer(struct tty_struct *tty) return count; } -static void -__sclp_vt220_flush_buffer(void) -{ - unsigned long flags; - - sclp_vt220_emit_current(); - spin_lock_irqsave(&sclp_vt220_lock, flags); - if (timer_pending(&sclp_vt220_timer)) - del_timer(&sclp_vt220_timer); - while (sclp_vt220_outqueue_count > 0) { - spin_unlock_irqrestore(&sclp_vt220_lock, flags); - sclp_sync_wait(); - spin_lock_irqsave(&sclp_vt220_lock, flags); - } - spin_unlock_irqrestore(&sclp_vt220_lock, flags); -} - /* * Pass on all buffers to the hardware. Return only when there are no more * buffers pending. @@ -617,10 +593,8 @@ sclp_vt220_flush_buffer(struct tty_struct *tty) sclp_vt220_emit_current(); } -/* - * Initialize all relevant components and register driver with system. - */ -static void __init __sclp_vt220_cleanup(void) +/* Release allocated pages. */ +static void __init __sclp_vt220_free_pages(void) { struct list_head *page, *p; @@ -631,25 +605,33 @@ static void __init __sclp_vt220_cleanup(void) else free_bootmem((unsigned long) page, PAGE_SIZE); } - if (!list_empty(&sclp_vt220_register.list)) - sclp_unregister(&sclp_vt220_register); - sclp_vt220_initialized = 0; } -static int __init __sclp_vt220_init(void) +/* Release memory and unregister from sclp core. Controlled by init counting - + * only the last invoker will actually perform these actions. */ +static void __init __sclp_vt220_cleanup(void) +{ + sclp_vt220_init_count--; + if (sclp_vt220_init_count != 0) + return; + sclp_unregister(&sclp_vt220_register); + __sclp_vt220_free_pages(); +} + +/* Allocate buffer pages and register with sclp core. Controlled by init + * counting - only the first invoker will actually perform these actions. */ +static int __init __sclp_vt220_init(int num_pages) { void *page; int i; - int num_pages; int rc; - if (sclp_vt220_initialized) + sclp_vt220_init_count++; + if (sclp_vt220_init_count != 1) return 0; - sclp_vt220_initialized = 1; spin_lock_init(&sclp_vt220_lock); INIT_LIST_HEAD(&sclp_vt220_empty); INIT_LIST_HEAD(&sclp_vt220_outqueue); - init_waitqueue_head(&sclp_vt220_waitq); init_timer(&sclp_vt220_timer); sclp_vt220_current_request = NULL; sclp_vt220_buffered_chars = 0; @@ -658,24 +640,22 @@ static int __init __sclp_vt220_init(void) sclp_vt220_flush_later = 0; /* Allocate pages for output buffering */ - num_pages = slab_is_available() ? MAX_KMEM_PAGES : MAX_CONSOLE_PAGES; for (i = 0; i < num_pages; i++) { if (slab_is_available()) page = (void *) get_zeroed_page(GFP_KERNEL | GFP_DMA); else page = alloc_bootmem_low_pages(PAGE_SIZE); if (!page) { - __sclp_vt220_cleanup(); - return -ENOMEM; + rc = -ENOMEM; + goto out; } list_add_tail((struct list_head *) page, &sclp_vt220_empty); } rc = sclp_register(&sclp_vt220_register); +out: if (rc) { - printk(KERN_ERR SCLP_VT220_PRINT_HEADER - "could not register vt220 - " - "sclp_register returned %d\n", rc); - __sclp_vt220_cleanup(); + __sclp_vt220_free_pages(); + sclp_vt220_init_count--; } return rc; } @@ -698,15 +678,13 @@ static int __init sclp_vt220_tty_init(void) { struct tty_driver *driver; int rc; - int cleanup; /* Note: we're not testing for CONSOLE_IS_SCLP here to preserve * symmetry between VM and LPAR systems regarding ttyS1. */ driver = alloc_tty_driver(1); if (!driver) return -ENOMEM; - cleanup = !sclp_vt220_initialized; - rc = __sclp_vt220_init(); + rc = __sclp_vt220_init(MAX_KMEM_PAGES); if (rc) goto out_driver; @@ -722,18 +700,13 @@ static int __init sclp_vt220_tty_init(void) tty_set_operations(driver, &sclp_vt220_ops); rc = tty_register_driver(driver); - if (rc) { - printk(KERN_ERR SCLP_VT220_PRINT_HEADER - "could not register tty - " - "tty_register_driver returned %d\n", rc); + if (rc) goto out_init; - } sclp_vt220_driver = driver; return 0; out_init: - if (cleanup) - __sclp_vt220_cleanup(); + __sclp_vt220_cleanup(); out_driver: put_tty_driver(driver); return rc; @@ -755,24 +728,46 @@ sclp_vt220_con_device(struct console *c, int *index) return sclp_vt220_driver; } -/* - * 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. - * Note that this function may be called from within an interrupt context. - */ -static void -sclp_vt220_con_unblank(void) +static void __sclp_vt220_flush_buffer(void) +{ + unsigned long flags; + + sclp_vt220_emit_current(); + spin_lock_irqsave(&sclp_vt220_lock, flags); + if (timer_pending(&sclp_vt220_timer)) + del_timer(&sclp_vt220_timer); + while (sclp_vt220_outqueue_count > 0) { + spin_unlock_irqrestore(&sclp_vt220_lock, flags); + sclp_sync_wait(); + spin_lock_irqsave(&sclp_vt220_lock, flags); + } + spin_unlock_irqrestore(&sclp_vt220_lock, flags); +} + +static int +sclp_vt220_notify(struct notifier_block *self, + unsigned long event, void *data) { __sclp_vt220_flush_buffer(); + return NOTIFY_OK; } +static struct notifier_block on_panic_nb = { + .notifier_call = sclp_vt220_notify, + .priority = 1, +}; + +static struct notifier_block on_reboot_nb = { + .notifier_call = sclp_vt220_notify, + .priority = 1, +}; + /* Structure needed to register with printk */ static struct console sclp_vt220_console = { .name = SCLP_VT220_CONSOLE_NAME, .write = sclp_vt220_con_write, .device = sclp_vt220_con_device, - .unblank = sclp_vt220_con_unblank, .flags = CON_PRINTBUFFER, .index = SCLP_VT220_CONSOLE_INDEX }; @@ -784,10 +779,12 @@ sclp_vt220_con_init(void) if (!CONSOLE_IS_SCLP) return 0; - rc = __sclp_vt220_init(); + rc = __sclp_vt220_init(MAX_CONSOLE_PAGES); if (rc) return rc; /* Attach linux console */ + atomic_notifier_chain_register(&panic_notifier_list, &on_panic_nb); + register_reboot_notifier(&on_reboot_nb); register_console(&sclp_vt220_console); return 0; }