/* * 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 * Martin Schwidefsky */ #include #include #include #include #include #include #include #include #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);