diff options
Diffstat (limited to 'drivers/s390/char/sclp_con.c')
| -rw-r--r-- | drivers/s390/char/sclp_con.c | 252 |
1 files changed, 252 insertions, 0 deletions
diff --git a/drivers/s390/char/sclp_con.c b/drivers/s390/char/sclp_con.c new file mode 100644 index 00000000000..10ef22f1354 --- /dev/null +++ b/drivers/s390/char/sclp_con.c @@ -0,0 +1,252 @@ +/* + * drivers/s390/char/sclp_con.c + * 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> + */ + +#include <linux/config.h> +#include <linux/kmod.h> +#include <linux/console.h> +#include <linux/init.h> +#include <linux/timer.h> +#include <linux/jiffies.h> +#include <linux/bootmem.h> +#include <linux/err.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" + +/* Lock to guard over changes to global variables */ +static spinlock_t sclp_con_lock; +/* List of free pages that can be used for console output buffering */ +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; + +/* Output format for console messages */ +static unsigned short sclp_con_columns; +static unsigned short sclp_con_width_htab; + +static void +sclp_conbuf_callback(struct sclp_buffer *buffer, int rc) +{ + unsigned long flags; + void *page; + + 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); + spin_unlock_irqrestore(&sclp_con_lock, flags); + } while (buffer && sclp_emit_buffer(buffer, sclp_conbuf_callback)); +} + +static inline 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; + 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++; + 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); +} + +/* + * When this routine is called from the timer then we flush the + * temporary write buffer without further waiting on a final new line. + */ +static void +sclp_console_timeout(unsigned long data) +{ + sclp_conbuf_emit(); +} + +/* + * Writes the given message to S390 system console + */ +static void +sclp_console_write(struct console *console, const char *message, + unsigned int count) +{ + unsigned long flags; + void *page; + int written; + + if (count == 0) + return; + spin_lock_irqsave(&sclp_con_lock, flags); + /* + * process escape characters, write message into buffer, + * send buffer to SCLP + */ + do { + /* make sure we have a console output buffer */ + if (sclp_conbuf == NULL) { + while (list_empty(&sclp_con_pages)) { + spin_unlock_irqrestore(&sclp_con_lock, flags); + sclp_sync_wait(); + spin_lock_irqsave(&sclp_con_lock, flags); + } + page = sclp_con_pages.next; + list_del((struct list_head *) page); + sclp_conbuf = sclp_make_buffer(page, sclp_con_columns, + sclp_con_width_htab); + } + /* try to write the string to the current output buffer */ + written = sclp_write(sclp_conbuf, (const unsigned char *) + message, count); + if (written == count) + break; + /* + * Not all characters could be written to the current + * output buffer. Emit the buffer, create a new buffer + * and then output the rest of the string. + */ + spin_unlock_irqrestore(&sclp_con_lock, flags); + sclp_conbuf_emit(); + spin_lock_irqsave(&sclp_con_lock, flags); + message += written; + count -= written; + } while (count > 0); + /* Setup timer to output current console buffer after 1/10 second */ + if (sclp_conbuf != NULL && sclp_chars_in_buffer(sclp_conbuf) != 0 && + !timer_pending(&sclp_con_timer)) { + init_timer(&sclp_con_timer); + sclp_con_timer.function = sclp_console_timeout; + sclp_con_timer.data = 0UL; + sclp_con_timer.expires = jiffies + HZ/10; + add_timer(&sclp_con_timer); + } + spin_unlock_irqrestore(&sclp_con_lock, flags); +} + +static struct tty_driver * +sclp_console_device(struct console *c, int *index) +{ + *index = c->index; + return sclp_tty_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. + */ +static void +sclp_console_unblank(void) +{ + unsigned long flags; + + sclp_conbuf_emit(); + 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); + } + spin_unlock_irqrestore(&sclp_con_lock, flags); +} + +/* + * used to register the SCLP console to the kernel and to + * give printk necessary information + */ +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 */ +}; + +/* + * called by console_init() in drivers/char/tty_io.c at boot-time. + */ +static int __init +sclp_console_init(void) +{ + void *page; + int i; + int rc; + + if (!CONSOLE_IS_SCLP) + return 0; + rc = sclp_rw_init(); + if (rc) + 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); + } + 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); + + /* Set output format */ + if (MACHINE_IS_VM) + /* + * save 4 characters for the CPU number + * written at start of each line by VM/CP + */ + sclp_con_columns = 76; + else + sclp_con_columns = 80; + sclp_con_width_htab = 8; + + /* enable printk-access to this driver */ + register_console(&sclp_console); + return 0; +} + +console_initcall(sclp_console_init); |