// SPDX-License-Identifier: GPL-2.0 /* * SCLP VT220 terminal driver. * * Copyright IBM Corp. 2003, 2009 * * Author(s): Peter Oberparleiter <Peter.Oberparleiter@de.ibm.com> */ #include <linux/module.h> #include <linux/spinlock.h> #include <linux/panic_notifier.h> #include <linux/list.h> #include <linux/wait.h> #include <linux/timer.h> #include <linux/kernel.h> #include <linux/sysrq.h> #include <linux/tty.h> #include <linux/tty_driver.h> #include <linux/tty_flip.h> #include <linux/errno.h> #include <linux/mm.h> #include <linux/major.h> #include <linux/console.h> #include <linux/kdev_t.h> #include <linux/interrupt.h> #include <linux/init.h> #include <linux/reboot.h> #include <linux/slab.h> #include <linux/uaccess.h> #include "sclp.h" #include "ctrlchar.h" #define SCLP_VT220_MAJOR TTY_MAJOR #define SCLP_VT220_MINOR 65 #define SCLP_VT220_DRIVER_NAME "sclp_vt220" #define SCLP_VT220_DEVICE_NAME "ttysclp" #define SCLP_VT220_CONSOLE_NAME "ttysclp" #define SCLP_VT220_CONSOLE_INDEX 0 /* console=ttysclp0 */ /* Representation of a single write request */ struct sclp_vt220_request { struct list_head list; struct sclp_req sclp_req; int retry_count; }; /* VT220 SCCB */ struct sclp_vt220_sccb { struct sccb_header header; struct evbuf_header evbuf; }; #define SCLP_VT220_MAX_CHARS_PER_BUFFER (PAGE_SIZE - \ sizeof(struct sclp_vt220_request) - \ sizeof(struct sclp_vt220_sccb)) /* Structures and data needed to register tty driver */ static struct tty_driver *sclp_vt220_driver; static struct tty_port sclp_vt220_port; /* Lock to protect internal data from concurrent access */ static DEFINE_SPINLOCK(sclp_vt220_lock); /* List of empty pages to be used as write request buffers */ static LIST_HEAD(sclp_vt220_empty); /* List of pending requests */ static LIST_HEAD(sclp_vt220_outqueue); /* Flag that output queue is currently running */ static int sclp_vt220_queue_running; /* Timer used for delaying write requests to merge subsequent messages into * a single buffer */ static struct timer_list sclp_vt220_timer; /* Pointer to current request buffer which has been partially filled but not * yet sent */ static struct sclp_vt220_request *sclp_vt220_current_request; /* Number of characters in current request buffer */ static int sclp_vt220_buffered_chars; /* 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 * another buffer */ static int sclp_vt220_flush_later; static void sclp_vt220_receiver_fn(struct evbuf_header *evbuf); static int __sclp_vt220_emit(struct sclp_vt220_request *request); static void sclp_vt220_emit_current(void); /* Registration structure for SCLP output event buffers */ static struct sclp_register sclp_vt220_register = { .send_mask = EVTYP_VT220MSG_MASK, }; /* Registration structure for SCLP input event buffers */ static struct sclp_register sclp_vt220_register_input = { .receive_mask = EVTYP_VT220MSG_MASK, .receiver_fn = sclp_vt220_receiver_fn, }; /* * Put provided request buffer back into queue and check emit pending * buffers if necessary. */ static void sclp_vt220_process_queue(struct sclp_vt220_request *request) { unsigned long flags; void *page; do { /* Put buffer back to list of empty buffers */ page = request->sclp_req.sccb; spin_lock_irqsave(&sclp_vt220_lock, flags); /* Move request from outqueue to empty queue */ list_del(&request->list); list_add_tail((struct list_head *) page, &sclp_vt220_empty); /* Check if there is a pending buffer on the out queue. */ request = NULL; if (!list_empty(&sclp_vt220_outqueue)) request = list_entry(sclp_vt220_outqueue.next, struct sclp_vt220_request, list); if (!request) { sclp_vt220_queue_running = 0; spin_unlock_irqrestore(&sclp_vt220_lock, flags); break; } spin_unlock_irqrestore(&sclp_vt220_lock, flags); } while (__sclp_vt220_emit(request)); if (request == NULL && sclp_vt220_flush_later) sclp_vt220_emit_current(); tty_port_tty_wakeup(&sclp_vt220_port); } #define SCLP_BUFFER_MAX_RETRY 1 /* * Callback through which the result of a write request is reported by the * SCLP. */ static void sclp_vt220_callback(struct sclp_req *request, void *data) { struct sclp_vt220_request *vt220_request; struct sclp_vt220_sccb *sccb; vt220_request = (struct sclp_vt220_request *) data; if (request->status == SCLP_REQ_FAILED) { sclp_vt220_process_queue(vt220_request); return; } sccb = (struct sclp_vt220_sccb *) vt220_request->sclp_req.sccb; /* Check SCLP response code and choose suitable action */ switch (sccb->header.response_code) { case 0x0020 : break; case 0x05f0: /* Target resource in improper state */ break; case 0x0340: /* Contained SCLP equipment check */ if (++vt220_request->retry_count > SCLP_BUFFER_MAX_RETRY) break; /* Remove processed buffers and requeue rest */ if (sclp_remove_processed((struct sccb_header *) sccb) > 0) { /* Not all buffers were processed */ sccb->header.response_code = 0x0000; vt220_request->sclp_req.status = SCLP_REQ_FILLED; if (sclp_add_request(request) == 0) return; } break; case 0x0040: /* SCLP equipment check */ if (++vt220_request->retry_count > SCLP_BUFFER_MAX_RETRY) break; sccb->header.response_code = 0x0000; vt220_request->sclp_req.status = SCLP_REQ_FILLED; if (sclp_add_request(request) == 0) return; break; default: break; } sclp_vt220_process_queue(vt220_request); } /* * Emit vt220 request buffer to SCLP. Return zero on success, non-zero * otherwise. */ static int __sclp_vt220_emit(struct sclp_vt220_request *request) { request->sclp_req.command = SCLP_CMDW_WRITE_EVENT_DATA; request->sclp_req.status = SCLP_REQ_FILLED; request->sclp_req.callback = sclp_vt220_callback; request->sclp_req.callback_data = (void *) request; return sclp_add_request(&request->sclp_req); } /* * Queue and emit current request. */ static void sclp_vt220_emit_current(void) { unsigned long flags; struct sclp_vt220_request *request; struct sclp_vt220_sccb *sccb; spin_lock_irqsave(&sclp_vt220_lock, flags); if (sclp_vt220_current_request) { sccb = (struct sclp_vt220_sccb *) sclp_vt220_current_request->sclp_req.sccb; /* Only emit buffers with content */ if (sccb->header.length != sizeof(struct sclp_vt220_sccb)) { list_add_tail(&sclp_vt220_current_request->list, &sclp_vt220_outqueue); sclp_vt220_current_request = NULL; if (timer_pending(&sclp_vt220_timer)) del_timer(&sclp_vt220_timer); } sclp_vt220_flush_later = 0; } if (sclp_vt220_queue_running) goto out_unlock; if (list_empty(&sclp_vt220_outqueue)) goto out_unlock; request = list_first_entry(&sclp_vt220_outqueue, struct sclp_vt220_request, list); sclp_vt220_queue_running = 1; spin_unlock_irqrestore(&sclp_vt220_lock, flags); if (__sclp_vt220_emit(request)) sclp_vt220_process_queue(request); return; out_unlock: spin_unlock_irqrestore(&sclp_vt220_lock, flags); } #define SCLP_NORMAL_WRITE 0x00 /* * Helper function to initialize a page with the sclp request structure. */ static struct sclp_vt220_request * sclp_vt220_initialize_page(void *page) { struct sclp_vt220_request *request; struct sclp_vt220_sccb *sccb; /* Place request structure at end of page */ request = ((struct sclp_vt220_request *) ((addr_t) page + PAGE_SIZE)) - 1; request->retry_count = 0; request->sclp_req.sccb = page; /* SCCB goes at start of page */ sccb = (struct sclp_vt220_sccb *) page; memset((void *) sccb, 0, sizeof(struct sclp_vt220_sccb)); sccb->header.length = sizeof(struct sclp_vt220_sccb); sccb->header.function_code = SCLP_NORMAL_WRITE; sccb->header.response_code = 0x0000; sccb->evbuf.type = EVTYP_VT220MSG; sccb->evbuf.length = sizeof(struct evbuf_header); return request; } static inline unsigned int sclp_vt220_space_left(struct sclp_vt220_request *request) { struct sclp_vt220_sccb *sccb; sccb = (struct sclp_vt220_sccb *) request->sclp_req.sccb; return PAGE_SIZE - sizeof(struct sclp_vt220_request) - sccb->header.length; } static inline unsigned int sclp_vt220_chars_stored(struct sclp_vt220_request *request) { struct sclp_vt220_sccb *sccb; sccb = (struct sclp_vt220_sccb *) request->sclp_req.sccb; return sccb->evbuf.length - sizeof(struct evbuf_header); } /* * Add msg to buffer associated with request. Return the number of characters * added. */ static int sclp_vt220_add_msg(struct sclp_vt220_request *request, const unsigned char *msg, int count, int convertlf) { struct sclp_vt220_sccb *sccb; void *buffer; unsigned char c; int from; int to; if (count > sclp_vt220_space_left(request)) count = sclp_vt220_space_left(request); if (count <= 0) return 0; sccb = (struct sclp_vt220_sccb *) request->sclp_req.sccb; buffer = (void *) ((addr_t) sccb + sccb->header.length); if (convertlf) { /* Perform Linefeed conversion (0x0a -> 0x0a 0x0d)*/ for (from=0, to=0; (from < count) && (to < sclp_vt220_space_left(request)); from++) { /* Retrieve character */ c = msg[from]; /* Perform conversion */ if (c == 0x0a) { if (to + 1 < sclp_vt220_space_left(request)) { ((unsigned char *) buffer)[to++] = c; ((unsigned char *) buffer)[to++] = 0x0d; } else break; } else ((unsigned char *) buffer)[to++] = c; } sccb->header.length += to; sccb->evbuf.length += to; return from; } else { memcpy(buffer, (const void *) msg, count); sccb->header.length += count; sccb->evbuf.length += count; return count; } } /* * Emit buffer after having waited long enough for more data to arrive. */ static void sclp_vt220_timeout(struct timer_list *unused) { sclp_vt220_emit_current(); } #define BUFFER_MAX_DELAY HZ/20 /* * Drop oldest console buffer if sclp_con_drop is set */ static int sclp_vt220_drop_buffer(void) { struct list_head *list; struct sclp_vt220_request *request; void *page; if (!sclp_console_drop) return 0; list = sclp_vt220_outqueue.next; if (sclp_vt220_queue_running) /* The first element is in I/O */ list = list->next; if (list == &sclp_vt220_outqueue) return 0; list_del(list); request = list_entry(list, struct sclp_vt220_request, list); page = request->sclp_req.sccb; list_add_tail((struct list_head *) page, &sclp_vt220_empty); return 1; } /* * Internal implementation of the write function. Write COUNT bytes of data * from memory at BUF * to the SCLP interface. In case that the data does not fit into the current * write buffer, emit the current one and allocate a new one. If there are no * more empty buffers available, wait until one gets emptied. If DO_SCHEDULE * is non-zero, the buffer will be scheduled for emitting after a timeout - * otherwise the user has to explicitly call the flush function. * A non-zero CONVERTLF parameter indicates that 0x0a characters in the message * buffer should be converted to 0x0a 0x0d. After completion, return the number * of bytes written. */ static int __sclp_vt220_write(const unsigned char *buf, int count, int do_schedule, int convertlf, int may_fail) { unsigned long flags; void *page; int written; int overall_written; if (count <= 0) return 0; overall_written = 0; spin_lock_irqsave(&sclp_vt220_lock, flags); do { /* Create an sclp output buffer if none exists yet */ if (sclp_vt220_current_request == NULL) { if (list_empty(&sclp_vt220_empty)) sclp_console_full++; while (list_empty(&sclp_vt220_empty)) { if (may_fail) goto out; if (sclp_vt220_drop_buffer()) break; spin_unlock_irqrestore(&sclp_vt220_lock, flags); sclp_sync_wait(); spin_lock_irqsave(&sclp_vt220_lock, flags); } page = (void *) sclp_vt220_empty.next; list_del((struct list_head *) page); sclp_vt220_current_request = sclp_vt220_initialize_page(page); } /* Try to write the string to the current request buffer */ written = sclp_vt220_add_msg(sclp_vt220_current_request, buf, count, convertlf); overall_written += written; 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_vt220_lock, flags); sclp_vt220_emit_current(); spin_lock_irqsave(&sclp_vt220_lock, flags); buf += written; count -= written; } while (count > 0); /* Setup timer to output current console buffer after some time */ if (sclp_vt220_current_request != NULL && !timer_pending(&sclp_vt220_timer) && do_schedule) { sclp_vt220_timer.expires = jiffies + BUFFER_MAX_DELAY; add_timer(&sclp_vt220_timer); } out: spin_unlock_irqrestore(&sclp_vt220_lock, flags); return overall_written; } /* * This routine is called by the kernel to write a series of * characters to the tty device. The characters may come from * user space or kernel space. This routine will return the * number of characters actually accepted for writing. */ static int sclp_vt220_write(struct tty_struct *tty, const unsigned char *buf, int count) { return __sclp_vt220_write(buf, count, 1, 0, 1); } #define SCLP_VT220_SESSION_ENDED 0x01 #define SCLP_VT220_SESSION_STARTED 0x80 #define SCLP_VT220_SESSION_DATA 0x00 #ifdef CONFIG_MAGIC_SYSRQ static int sysrq_pressed; static struct sysrq_work sysrq; static void sclp_vt220_reset_session(void) { sysrq_pressed = 0; } static void sclp_vt220_handle_input(const char *buffer, unsigned int count) { int i; for (i = 0; i < count; i++) { /* Handle magic sys request */ if (buffer[i] == ('O' ^ 0100)) { /* CTRL-O */ /* * If pressed again, reset sysrq_pressed * and flip CTRL-O character */ sysrq_pressed = !sysrq_pressed; if (sysrq_pressed) continue; } else if (sysrq_pressed) { sysrq.key = buffer[i]; schedule_sysrq_work(&sysrq); sysrq_pressed = 0; continue; } tty_insert_flip_char(&sclp_vt220_port, buffer[i], 0); } } #else static void sclp_vt220_reset_session(void) { } static void sclp_vt220_handle_input(const char *buffer, unsigned int count) { tty_insert_flip_string(&sclp_vt220_port, buffer, count); } #endif /* * Called by the SCLP to report incoming event buffers. */ static void sclp_vt220_receiver_fn(struct evbuf_header *evbuf) { char *buffer; unsigned int count; buffer = (char *) ((addr_t) evbuf + sizeof(struct evbuf_header)); count = evbuf->length - sizeof(struct evbuf_header); switch (*buffer) { case SCLP_VT220_SESSION_ENDED: case SCLP_VT220_SESSION_STARTED: sclp_vt220_reset_session(); break; case SCLP_VT220_SESSION_DATA: /* Send input to line discipline */ buffer++; count--; sclp_vt220_handle_input(buffer, count); tty_flip_buffer_push(&sclp_vt220_port); break; } } /* * This routine is called when a particular tty device is opened. */ static int sclp_vt220_open(struct tty_struct *tty, struct file *filp) { if (tty->count == 1) { tty_port_tty_set(&sclp_vt220_port, tty); if (!tty->winsize.ws_row && !tty->winsize.ws_col) { tty->winsize.ws_row = 24; tty->winsize.ws_col = 80; } } return 0; } /* * This routine is called when a particular tty device is closed. */ static void sclp_vt220_close(struct tty_struct *tty, struct file *filp) { if (tty->count == 1) tty_port_tty_set(&sclp_vt220_port, NULL); } /* * This routine is called by the kernel to write a single * 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. */ static int sclp_vt220_put_char(struct tty_struct *tty, unsigned char ch) { return __sclp_vt220_write(&ch, 1, 0, 0, 1); } /* * This routine is called by the kernel after it has written a * series of characters to the tty device using put_char(). */ static void sclp_vt220_flush_chars(struct tty_struct *tty) { if (!sclp_vt220_queue_running) sclp_vt220_emit_current(); else sclp_vt220_flush_later = 1; } /* * This routine returns the numbers of characters the tty driver * will accept for queuing to be written. This number is subject * to change as output buffers get emptied, or if the output flow * control is acted. */ static unsigned int sclp_vt220_write_room(struct tty_struct *tty) { unsigned long flags; struct list_head *l; unsigned int count; spin_lock_irqsave(&sclp_vt220_lock, flags); count = 0; if (sclp_vt220_current_request != NULL) count = sclp_vt220_space_left(sclp_vt220_current_request); list_for_each(l, &sclp_vt220_empty) count += SCLP_VT220_MAX_CHARS_PER_BUFFER; spin_unlock_irqrestore(&sclp_vt220_lock, flags); return count; } /* * Return number of buffered chars. */ static unsigned int sclp_vt220_chars_in_buffer(struct tty_struct *tty) { unsigned long flags; struct list_head *l; struct sclp_vt220_request *r; unsigned int count = 0; spin_lock_irqsave(&sclp_vt220_lock, flags); if (sclp_vt220_current_request != NULL) count = sclp_vt220_chars_stored(sclp_vt220_current_request); list_for_each(l, &sclp_vt220_outqueue) { r = list_entry(l, struct sclp_vt220_request, list); count += sclp_vt220_chars_stored(r); } spin_unlock_irqrestore(&sclp_vt220_lock, flags); return count; } /* * Pass on all buffers to the hardware. Return only when there are no more * buffers pending. */ static void sclp_vt220_flush_buffer(struct tty_struct *tty) { sclp_vt220_emit_current(); } /* Release allocated pages. */ static void __init __sclp_vt220_free_pages(void) { struct list_head *page, *p; list_for_each_safe(page, p, &sclp_vt220_empty) { list_del(page); free_page((unsigned long) page); } } /* 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(); tty_port_destroy(&sclp_vt220_port); } /* 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 rc; sclp_vt220_init_count++; if (sclp_vt220_init_count != 1) return 0; timer_setup(&sclp_vt220_timer, sclp_vt220_timeout, 0); tty_port_init(&sclp_vt220_port); sclp_vt220_current_request = NULL; sclp_vt220_buffered_chars = 0; sclp_vt220_flush_later = 0; /* Allocate pages for output buffering */ rc = -ENOMEM; for (i = 0; i < num_pages; i++) { page = (void *) get_zeroed_page(GFP_KERNEL | GFP_DMA); if (!page) goto out; list_add_tail(page, &sclp_vt220_empty); } rc = sclp_register(&sclp_vt220_register); out: if (rc) { __sclp_vt220_free_pages(); sclp_vt220_init_count--; tty_port_destroy(&sclp_vt220_port); } return rc; } static const struct tty_operations sclp_vt220_ops = { .open = sclp_vt220_open, .close = sclp_vt220_close, .write = sclp_vt220_write, .put_char = sclp_vt220_put_char, .flush_chars = sclp_vt220_flush_chars, .write_room = sclp_vt220_write_room, .chars_in_buffer = sclp_vt220_chars_in_buffer, .flush_buffer = sclp_vt220_flush_buffer, }; /* * Register driver with SCLP and Linux and initialize internal tty structures. */ static int __init sclp_vt220_tty_init(void) { struct tty_driver *driver; int rc; /* 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; rc = __sclp_vt220_init(MAX_KMEM_PAGES); if (rc) goto out_driver; driver->driver_name = SCLP_VT220_DRIVER_NAME; driver->name = SCLP_VT220_DEVICE_NAME; driver->major = SCLP_VT220_MAJOR; driver->minor_start = SCLP_VT220_MINOR; driver->type = TTY_DRIVER_TYPE_SYSTEM; driver->subtype = SYSTEM_TYPE_TTY; driver->init_termios = tty_std_termios; driver->flags = TTY_DRIVER_REAL_RAW; tty_set_operations(driver, &sclp_vt220_ops); tty_port_link_device(&sclp_vt220_port, driver, 0); rc = tty_register_driver(driver); if (rc) goto out_init; rc = sclp_register(&sclp_vt220_register_input); if (rc) goto out_reg; sclp_vt220_driver = driver; return 0; out_reg: tty_unregister_driver(driver); out_init: __sclp_vt220_cleanup(); out_driver: put_tty_driver(driver); return rc; } __initcall(sclp_vt220_tty_init); 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_queue_running) { spin_unlock_irqrestore(&sclp_vt220_lock, flags); sclp_sync_wait(); spin_lock_irqsave(&sclp_vt220_lock, flags); } spin_unlock_irqrestore(&sclp_vt220_lock, flags); } #ifdef CONFIG_SCLP_VT220_CONSOLE static void sclp_vt220_con_write(struct console *con, const char *buf, unsigned int count) { __sclp_vt220_write((const unsigned char *) buf, count, 1, 1, 0); } static struct tty_driver * sclp_vt220_con_device(struct console *c, int *index) { *index = 0; return sclp_vt220_driver; } 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, .flags = CON_PRINTBUFFER, .index = SCLP_VT220_CONSOLE_INDEX }; static int __init sclp_vt220_con_init(void) { int rc; rc = __sclp_vt220_init(sclp_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; } console_initcall(sclp_vt220_con_init); #endif /* CONFIG_SCLP_VT220_CONSOLE */