| // SPDX-License-Identifier: GPL-2.0+ |
| /* |
| * Copyright (C) 2001 Anton Blanchard <anton@au.ibm.com>, IBM |
| * Copyright (C) 2001 Paul Mackerras <paulus@au.ibm.com>, IBM |
| * Copyright (C) 2004 Benjamin Herrenschmidt <benh@kernel.crashing.org>, IBM Corp. |
| * Copyright (C) 2004 IBM Corporation |
| * |
| * Additional Author(s): |
| * Ryan S. Arnold <rsa@us.ibm.com> |
| */ |
| |
| #include <linux/console.h> |
| #include <linux/cpumask.h> |
| #include <linux/init.h> |
| #include <linux/kbd_kern.h> |
| #include <linux/kernel.h> |
| #include <linux/kthread.h> |
| #include <linux/list.h> |
| #include <linux/major.h> |
| #include <linux/atomic.h> |
| #include <linux/sysrq.h> |
| #include <linux/tty.h> |
| #include <linux/tty_flip.h> |
| #include <linux/sched.h> |
| #include <linux/spinlock.h> |
| #include <linux/delay.h> |
| #include <linux/freezer.h> |
| #include <linux/slab.h> |
| #include <linux/serial_core.h> |
| |
| #include <linux/uaccess.h> |
| |
| #include "hvc_console.h" |
| |
| #define HVC_MAJOR 229 |
| #define HVC_MINOR 0 |
| |
| /* |
| * Wait this long per iteration while trying to push buffered data to the |
| * hypervisor before allowing the tty to complete a close operation. |
| */ |
| #define HVC_CLOSE_WAIT (HZ/100) /* 1/10 of a second */ |
| |
| /* |
| * These sizes are most efficient for vio, because they are the |
| * native transfer size. We could make them selectable in the |
| * future to better deal with backends that want other buffer sizes. |
| */ |
| #define N_OUTBUF 16 |
| #define N_INBUF 16 |
| |
| #define __ALIGNED__ __attribute__((__aligned__(sizeof(long)))) |
| |
| static struct tty_driver *hvc_driver; |
| static struct task_struct *hvc_task; |
| |
| /* Picks up late kicks after list walk but before schedule() */ |
| static int hvc_kicked; |
| |
| /* hvc_init is triggered from hvc_alloc, i.e. only when actually used */ |
| static atomic_t hvc_needs_init __read_mostly = ATOMIC_INIT(-1); |
| |
| static int hvc_init(void); |
| |
| #ifdef CONFIG_MAGIC_SYSRQ |
| static int sysrq_pressed; |
| #endif |
| |
| /* dynamic list of hvc_struct instances */ |
| static LIST_HEAD(hvc_structs); |
| |
| /* |
| * Protect the list of hvc_struct instances from inserts and removals during |
| * list traversal. |
| */ |
| static DEFINE_MUTEX(hvc_structs_mutex); |
| |
| /* |
| * This value is used to assign a tty->index value to a hvc_struct based |
| * upon order of exposure via hvc_probe(), when we can not match it to |
| * a console candidate registered with hvc_instantiate(). |
| */ |
| static int last_hvc = -1; |
| |
| /* |
| * Do not call this function with either the hvc_structs_mutex or the hvc_struct |
| * lock held. If successful, this function increments the kref reference |
| * count against the target hvc_struct so it should be released when finished. |
| */ |
| static struct hvc_struct *hvc_get_by_index(int index) |
| { |
| struct hvc_struct *hp; |
| unsigned long flags; |
| |
| mutex_lock(&hvc_structs_mutex); |
| |
| list_for_each_entry(hp, &hvc_structs, next) { |
| spin_lock_irqsave(&hp->lock, flags); |
| if (hp->index == index) { |
| tty_port_get(&hp->port); |
| spin_unlock_irqrestore(&hp->lock, flags); |
| mutex_unlock(&hvc_structs_mutex); |
| return hp; |
| } |
| spin_unlock_irqrestore(&hp->lock, flags); |
| } |
| hp = NULL; |
| mutex_unlock(&hvc_structs_mutex); |
| |
| return hp; |
| } |
| |
| static int __hvc_flush(const struct hv_ops *ops, uint32_t vtermno, bool wait) |
| { |
| if (wait) |
| might_sleep(); |
| |
| if (ops->flush) |
| return ops->flush(vtermno, wait); |
| return 0; |
| } |
| |
| static int hvc_console_flush(const struct hv_ops *ops, uint32_t vtermno) |
| { |
| return __hvc_flush(ops, vtermno, false); |
| } |
| |
| /* |
| * Wait for the console to flush before writing more to it. This sleeps. |
| */ |
| static int hvc_flush(struct hvc_struct *hp) |
| { |
| return __hvc_flush(hp->ops, hp->vtermno, true); |
| } |
| |
| /* |
| * Initial console vtermnos for console API usage prior to full console |
| * initialization. Any vty adapter outside this range will not have usable |
| * console interfaces but can still be used as a tty device. This has to be |
| * static because kmalloc will not work during early console init. |
| */ |
| static const struct hv_ops *cons_ops[MAX_NR_HVC_CONSOLES]; |
| static uint32_t vtermnos[MAX_NR_HVC_CONSOLES] = |
| {[0 ... MAX_NR_HVC_CONSOLES - 1] = -1}; |
| |
| /* |
| * Console APIs, NOT TTY. These APIs are available immediately when |
| * hvc_console_setup() finds adapters. |
| */ |
| |
| static void hvc_console_print(struct console *co, const char *b, |
| unsigned count) |
| { |
| char c[N_OUTBUF] __ALIGNED__; |
| unsigned i = 0, n = 0; |
| int r, donecr = 0, index = co->index; |
| |
| /* Console access attempt outside of acceptable console range. */ |
| if (index >= MAX_NR_HVC_CONSOLES) |
| return; |
| |
| /* This console adapter was removed so it is not usable. */ |
| if (vtermnos[index] == -1) |
| return; |
| |
| while (count > 0 || i > 0) { |
| if (count > 0 && i < sizeof(c)) { |
| if (b[n] == '\n' && !donecr) { |
| c[i++] = '\r'; |
| donecr = 1; |
| } else { |
| c[i++] = b[n++]; |
| donecr = 0; |
| --count; |
| } |
| } else { |
| r = cons_ops[index]->put_chars(vtermnos[index], c, i); |
| if (r <= 0) { |
| /* throw away characters on error |
| * but spin in case of -EAGAIN */ |
| if (r != -EAGAIN) { |
| i = 0; |
| } else { |
| hvc_console_flush(cons_ops[index], |
| vtermnos[index]); |
| } |
| } else if (r > 0) { |
| i -= r; |
| if (i > 0) |
| memmove(c, c+r, i); |
| } |
| } |
| } |
| hvc_console_flush(cons_ops[index], vtermnos[index]); |
| } |
| |
| static struct tty_driver *hvc_console_device(struct console *c, int *index) |
| { |
| if (vtermnos[c->index] == -1) |
| return NULL; |
| |
| *index = c->index; |
| return hvc_driver; |
| } |
| |
| static int hvc_console_setup(struct console *co, char *options) |
| { |
| if (co->index < 0 || co->index >= MAX_NR_HVC_CONSOLES) |
| return -ENODEV; |
| |
| if (vtermnos[co->index] == -1) |
| return -ENODEV; |
| |
| return 0; |
| } |
| |
| static struct console hvc_console = { |
| .name = "hvc", |
| .write = hvc_console_print, |
| .device = hvc_console_device, |
| .setup = hvc_console_setup, |
| .flags = CON_PRINTBUFFER, |
| .index = -1, |
| }; |
| |
| /* |
| * Early console initialization. Precedes driver initialization. |
| * |
| * (1) we are first, and the user specified another driver |
| * -- index will remain -1 |
| * (2) we are first and the user specified no driver |
| * -- index will be set to 0, then we will fail setup. |
| * (3) we are first and the user specified our driver |
| * -- index will be set to user specified driver, and we will fail |
| * (4) we are after driver, and this initcall will register us |
| * -- if the user didn't specify a driver then the console will match |
| * |
| * Note that for cases 2 and 3, we will match later when the io driver |
| * calls hvc_instantiate() and call register again. |
| */ |
| static int __init hvc_console_init(void) |
| { |
| register_console(&hvc_console); |
| return 0; |
| } |
| console_initcall(hvc_console_init); |
| |
| /* callback when the kboject ref count reaches zero. */ |
| static void hvc_port_destruct(struct tty_port *port) |
| { |
| struct hvc_struct *hp = container_of(port, struct hvc_struct, port); |
| unsigned long flags; |
| |
| mutex_lock(&hvc_structs_mutex); |
| |
| spin_lock_irqsave(&hp->lock, flags); |
| list_del(&(hp->next)); |
| spin_unlock_irqrestore(&hp->lock, flags); |
| |
| mutex_unlock(&hvc_structs_mutex); |
| |
| kfree(hp); |
| } |
| |
| static void hvc_check_console(int index) |
| { |
| /* Already enabled, bail out */ |
| if (hvc_console.flags & CON_ENABLED) |
| return; |
| |
| /* If this index is what the user requested, then register |
| * now (setup won't fail at this point). It's ok to just |
| * call register again if previously .setup failed. |
| */ |
| if (index == hvc_console.index) |
| register_console(&hvc_console); |
| } |
| |
| /* |
| * hvc_instantiate() is an early console discovery method which locates |
| * consoles * prior to the vio subsystem discovering them. Hotplugged |
| * vty adapters do NOT get an hvc_instantiate() callback since they |
| * appear after early console init. |
| */ |
| int hvc_instantiate(uint32_t vtermno, int index, const struct hv_ops *ops) |
| { |
| struct hvc_struct *hp; |
| |
| if (index < 0 || index >= MAX_NR_HVC_CONSOLES) |
| return -1; |
| |
| if (vtermnos[index] != -1) |
| return -1; |
| |
| /* make sure no no tty has been registered in this index */ |
| hp = hvc_get_by_index(index); |
| if (hp) { |
| tty_port_put(&hp->port); |
| return -1; |
| } |
| |
| vtermnos[index] = vtermno; |
| cons_ops[index] = ops; |
| |
| /* reserve all indices up to and including this index */ |
| if (last_hvc < index) |
| last_hvc = index; |
| |
| /* check if we need to re-register the kernel console */ |
| hvc_check_console(index); |
| |
| return 0; |
| } |
| EXPORT_SYMBOL_GPL(hvc_instantiate); |
| |
| /* Wake the sleeping khvcd */ |
| void hvc_kick(void) |
| { |
| hvc_kicked = 1; |
| wake_up_process(hvc_task); |
| } |
| EXPORT_SYMBOL_GPL(hvc_kick); |
| |
| static void hvc_unthrottle(struct tty_struct *tty) |
| { |
| hvc_kick(); |
| } |
| |
| static int hvc_install(struct tty_driver *driver, struct tty_struct *tty) |
| { |
| struct hvc_struct *hp; |
| int rc; |
| |
| /* Auto increments kref reference if found. */ |
| hp = hvc_get_by_index(tty->index); |
| if (!hp) |
| return -ENODEV; |
| |
| tty->driver_data = hp; |
| |
| rc = tty_port_install(&hp->port, driver, tty); |
| if (rc) |
| tty_port_put(&hp->port); |
| return rc; |
| } |
| |
| /* |
| * The TTY interface won't be used until after the vio layer has exposed the vty |
| * adapter to the kernel. |
| */ |
| static int hvc_open(struct tty_struct *tty, struct file * filp) |
| { |
| struct hvc_struct *hp = tty->driver_data; |
| unsigned long flags; |
| int rc = 0; |
| |
| spin_lock_irqsave(&hp->port.lock, flags); |
| /* Check and then increment for fast path open. */ |
| if (hp->port.count++ > 0) { |
| spin_unlock_irqrestore(&hp->port.lock, flags); |
| hvc_kick(); |
| return 0; |
| } /* else count == 0 */ |
| spin_unlock_irqrestore(&hp->port.lock, flags); |
| |
| tty_port_tty_set(&hp->port, tty); |
| |
| if (hp->ops->notifier_add) |
| rc = hp->ops->notifier_add(hp, hp->data); |
| |
| /* |
| * If the notifier fails we return an error. The tty layer |
| * will call hvc_close() after a failed open but we don't want to clean |
| * up there so we'll clean up here and clear out the previously set |
| * tty fields and return the kref reference. |
| */ |
| if (rc) { |
| tty_port_tty_set(&hp->port, NULL); |
| tty->driver_data = NULL; |
| tty_port_put(&hp->port); |
| printk(KERN_ERR "hvc_open: request_irq failed with rc %d.\n", rc); |
| } else |
| /* We are ready... raise DTR/RTS */ |
| if (C_BAUD(tty)) |
| if (hp->ops->dtr_rts) |
| hp->ops->dtr_rts(hp, 1); |
| |
| /* Force wakeup of the polling thread */ |
| hvc_kick(); |
| |
| return rc; |
| } |
| |
| static void hvc_close(struct tty_struct *tty, struct file * filp) |
| { |
| struct hvc_struct *hp; |
| unsigned long flags; |
| |
| if (tty_hung_up_p(filp)) |
| return; |
| |
| /* |
| * No driver_data means that this close was issued after a failed |
| * hvc_open by the tty layer's release_dev() function and we can just |
| * exit cleanly because the kref reference wasn't made. |
| */ |
| if (!tty->driver_data) |
| return; |
| |
| hp = tty->driver_data; |
| |
| spin_lock_irqsave(&hp->port.lock, flags); |
| |
| if (--hp->port.count == 0) { |
| spin_unlock_irqrestore(&hp->port.lock, flags); |
| /* We are done with the tty pointer now. */ |
| tty_port_tty_set(&hp->port, NULL); |
| |
| if (C_HUPCL(tty)) |
| if (hp->ops->dtr_rts) |
| hp->ops->dtr_rts(hp, 0); |
| |
| if (hp->ops->notifier_del) |
| hp->ops->notifier_del(hp, hp->data); |
| |
| /* cancel pending tty resize work */ |
| cancel_work_sync(&hp->tty_resize); |
| |
| /* |
| * Chain calls chars_in_buffer() and returns immediately if |
| * there is no buffered data otherwise sleeps on a wait queue |
| * waking periodically to check chars_in_buffer(). |
| */ |
| tty_wait_until_sent(tty, HVC_CLOSE_WAIT); |
| } else { |
| if (hp->port.count < 0) |
| printk(KERN_ERR "hvc_close %X: oops, count is %d\n", |
| hp->vtermno, hp->port.count); |
| spin_unlock_irqrestore(&hp->port.lock, flags); |
| } |
| } |
| |
| static void hvc_cleanup(struct tty_struct *tty) |
| { |
| struct hvc_struct *hp = tty->driver_data; |
| |
| tty_port_put(&hp->port); |
| } |
| |
| static void hvc_hangup(struct tty_struct *tty) |
| { |
| struct hvc_struct *hp = tty->driver_data; |
| unsigned long flags; |
| |
| if (!hp) |
| return; |
| |
| /* cancel pending tty resize work */ |
| cancel_work_sync(&hp->tty_resize); |
| |
| spin_lock_irqsave(&hp->port.lock, flags); |
| |
| /* |
| * The N_TTY line discipline has problems such that in a close vs |
| * open->hangup case this can be called after the final close so prevent |
| * that from happening for now. |
| */ |
| if (hp->port.count <= 0) { |
| spin_unlock_irqrestore(&hp->port.lock, flags); |
| return; |
| } |
| |
| hp->port.count = 0; |
| spin_unlock_irqrestore(&hp->port.lock, flags); |
| tty_port_tty_set(&hp->port, NULL); |
| |
| hp->n_outbuf = 0; |
| |
| if (hp->ops->notifier_hangup) |
| hp->ops->notifier_hangup(hp, hp->data); |
| } |
| |
| /* |
| * Push buffered characters whether they were just recently buffered or waiting |
| * on a blocked hypervisor. Call this function with hp->lock held. |
| */ |
| static int hvc_push(struct hvc_struct *hp) |
| { |
| int n; |
| |
| n = hp->ops->put_chars(hp->vtermno, hp->outbuf, hp->n_outbuf); |
| if (n <= 0) { |
| if (n == 0 || n == -EAGAIN) { |
| hp->do_wakeup = 1; |
| return 0; |
| } |
| /* throw away output on error; this happens when |
| there is no session connected to the vterm. */ |
| hp->n_outbuf = 0; |
| } else |
| hp->n_outbuf -= n; |
| if (hp->n_outbuf > 0) |
| memmove(hp->outbuf, hp->outbuf + n, hp->n_outbuf); |
| else |
| hp->do_wakeup = 1; |
| |
| return n; |
| } |
| |
| static int hvc_write(struct tty_struct *tty, const unsigned char *buf, int count) |
| { |
| struct hvc_struct *hp = tty->driver_data; |
| unsigned long flags; |
| int rsize, written = 0; |
| |
| /* This write was probably executed during a tty close. */ |
| if (!hp) |
| return -EPIPE; |
| |
| /* FIXME what's this (unprotected) check for? */ |
| if (hp->port.count <= 0) |
| return -EIO; |
| |
| while (count > 0) { |
| int ret = 0; |
| |
| spin_lock_irqsave(&hp->lock, flags); |
| |
| rsize = hp->outbuf_size - hp->n_outbuf; |
| |
| if (rsize) { |
| if (rsize > count) |
| rsize = count; |
| memcpy(hp->outbuf + hp->n_outbuf, buf, rsize); |
| count -= rsize; |
| buf += rsize; |
| hp->n_outbuf += rsize; |
| written += rsize; |
| } |
| |
| if (hp->n_outbuf > 0) |
| ret = hvc_push(hp); |
| |
| spin_unlock_irqrestore(&hp->lock, flags); |
| |
| if (!ret) |
| break; |
| |
| if (count) { |
| if (hp->n_outbuf > 0) |
| hvc_flush(hp); |
| cond_resched(); |
| } |
| } |
| |
| /* |
| * Racy, but harmless, kick thread if there is still pending data. |
| */ |
| if (hp->n_outbuf) |
| hvc_kick(); |
| |
| return written; |
| } |
| |
| /** |
| * hvc_set_winsz() - Resize the hvc tty terminal window. |
| * @work: work structure. |
| * |
| * The routine shall not be called within an atomic context because it |
| * might sleep. |
| * |
| * Locking: hp->lock |
| */ |
| static void hvc_set_winsz(struct work_struct *work) |
| { |
| struct hvc_struct *hp; |
| unsigned long hvc_flags; |
| struct tty_struct *tty; |
| struct winsize ws; |
| |
| hp = container_of(work, struct hvc_struct, tty_resize); |
| |
| tty = tty_port_tty_get(&hp->port); |
| if (!tty) |
| return; |
| |
| spin_lock_irqsave(&hp->lock, hvc_flags); |
| ws = hp->ws; |
| spin_unlock_irqrestore(&hp->lock, hvc_flags); |
| |
| tty_do_resize(tty, &ws); |
| tty_kref_put(tty); |
| } |
| |
| /* |
| * This is actually a contract between the driver and the tty layer outlining |
| * how much write room the driver can guarantee will be sent OR BUFFERED. This |
| * driver MUST honor the return value. |
| */ |
| static int hvc_write_room(struct tty_struct *tty) |
| { |
| struct hvc_struct *hp = tty->driver_data; |
| |
| if (!hp) |
| return 0; |
| |
| return hp->outbuf_size - hp->n_outbuf; |
| } |
| |
| static int hvc_chars_in_buffer(struct tty_struct *tty) |
| { |
| struct hvc_struct *hp = tty->driver_data; |
| |
| if (!hp) |
| return 0; |
| return hp->n_outbuf; |
| } |
| |
| /* |
| * timeout will vary between the MIN and MAX values defined here. By default |
| * and during console activity we will use a default MIN_TIMEOUT of 10. When |
| * the console is idle, we increase the timeout value on each pass through |
| * msleep until we reach the max. This may be noticeable as a brief (average |
| * one second) delay on the console before the console responds to input when |
| * there has been no input for some time. |
| */ |
| #define MIN_TIMEOUT (10) |
| #define MAX_TIMEOUT (2000) |
| static u32 timeout = MIN_TIMEOUT; |
| |
| /* |
| * Maximum number of bytes to get from the console driver if hvc_poll is |
| * called from driver (and can't sleep). Any more than this and we break |
| * and start polling with khvcd. This value was derived from from an OpenBMC |
| * console with the OPAL driver that results in about 0.25ms interrupts off |
| * latency. |
| */ |
| #define HVC_ATOMIC_READ_MAX 128 |
| |
| #define HVC_POLL_READ 0x00000001 |
| #define HVC_POLL_WRITE 0x00000002 |
| |
| static int __hvc_poll(struct hvc_struct *hp, bool may_sleep) |
| { |
| struct tty_struct *tty; |
| int i, n, count, poll_mask = 0; |
| char buf[N_INBUF] __ALIGNED__; |
| unsigned long flags; |
| int read_total = 0; |
| int written_total = 0; |
| |
| spin_lock_irqsave(&hp->lock, flags); |
| |
| /* Push pending writes */ |
| if (hp->n_outbuf > 0) |
| written_total = hvc_push(hp); |
| |
| /* Reschedule us if still some write pending */ |
| if (hp->n_outbuf > 0) { |
| poll_mask |= HVC_POLL_WRITE; |
| /* If hvc_push() was not able to write, sleep a few msecs */ |
| timeout = (written_total) ? 0 : MIN_TIMEOUT; |
| } |
| |
| if (may_sleep) { |
| spin_unlock_irqrestore(&hp->lock, flags); |
| cond_resched(); |
| spin_lock_irqsave(&hp->lock, flags); |
| } |
| |
| /* No tty attached, just skip */ |
| tty = tty_port_tty_get(&hp->port); |
| if (tty == NULL) |
| goto bail; |
| |
| /* Now check if we can get data (are we throttled ?) */ |
| if (tty_throttled(tty)) |
| goto out; |
| |
| /* If we aren't notifier driven and aren't throttled, we always |
| * request a reschedule |
| */ |
| if (!hp->irq_requested) |
| poll_mask |= HVC_POLL_READ; |
| |
| read_again: |
| /* Read data if any */ |
| count = tty_buffer_request_room(&hp->port, N_INBUF); |
| |
| /* If flip is full, just reschedule a later read */ |
| if (count == 0) { |
| poll_mask |= HVC_POLL_READ; |
| goto out; |
| } |
| |
| n = hp->ops->get_chars(hp->vtermno, buf, count); |
| if (n <= 0) { |
| /* Hangup the tty when disconnected from host */ |
| if (n == -EPIPE) { |
| spin_unlock_irqrestore(&hp->lock, flags); |
| tty_hangup(tty); |
| spin_lock_irqsave(&hp->lock, flags); |
| } else if ( n == -EAGAIN ) { |
| /* |
| * Some back-ends can only ensure a certain min |
| * num of bytes read, which may be > 'count'. |
| * Let the tty clear the flip buff to make room. |
| */ |
| poll_mask |= HVC_POLL_READ; |
| } |
| goto out; |
| } |
| |
| for (i = 0; i < n; ++i) { |
| #ifdef CONFIG_MAGIC_SYSRQ |
| if (hp->index == hvc_console.index) { |
| /* Handle the SysRq Hack */ |
| /* XXX should support a sequence */ |
| if (buf[i] == '\x0f') { /* ^O */ |
| /* if ^O is pressed again, reset |
| * sysrq_pressed and flip ^O char */ |
| sysrq_pressed = !sysrq_pressed; |
| if (sysrq_pressed) |
| continue; |
| } else if (sysrq_pressed) { |
| handle_sysrq(buf[i]); |
| sysrq_pressed = 0; |
| continue; |
| } |
| } |
| #endif /* CONFIG_MAGIC_SYSRQ */ |
| tty_insert_flip_char(&hp->port, buf[i], 0); |
| } |
| read_total += n; |
| |
| if (may_sleep) { |
| /* Keep going until the flip is full */ |
| spin_unlock_irqrestore(&hp->lock, flags); |
| cond_resched(); |
| spin_lock_irqsave(&hp->lock, flags); |
| goto read_again; |
| } else if (read_total < HVC_ATOMIC_READ_MAX) { |
| /* Break and defer if it's a large read in atomic */ |
| goto read_again; |
| } |
| |
| /* |
| * Latency break, schedule another poll immediately. |
| */ |
| poll_mask |= HVC_POLL_READ; |
| |
| out: |
| /* Wakeup write queue if necessary */ |
| if (hp->do_wakeup) { |
| hp->do_wakeup = 0; |
| tty_wakeup(tty); |
| } |
| bail: |
| spin_unlock_irqrestore(&hp->lock, flags); |
| |
| if (read_total) { |
| /* Activity is occurring, so reset the polling backoff value to |
| a minimum for performance. */ |
| timeout = MIN_TIMEOUT; |
| |
| tty_flip_buffer_push(&hp->port); |
| } |
| tty_kref_put(tty); |
| |
| return poll_mask; |
| } |
| |
| int hvc_poll(struct hvc_struct *hp) |
| { |
| return __hvc_poll(hp, false); |
| } |
| EXPORT_SYMBOL_GPL(hvc_poll); |
| |
| /** |
| * __hvc_resize() - Update terminal window size information. |
| * @hp: HVC console pointer |
| * @ws: Terminal window size structure |
| * |
| * Stores the specified window size information in the hvc structure of @hp. |
| * The function schedule the tty resize update. |
| * |
| * Locking: Locking free; the function MUST be called holding hp->lock |
| */ |
| void __hvc_resize(struct hvc_struct *hp, struct winsize ws) |
| { |
| hp->ws = ws; |
| schedule_work(&hp->tty_resize); |
| } |
| EXPORT_SYMBOL_GPL(__hvc_resize); |
| |
| /* |
| * This kthread is either polling or interrupt driven. This is determined by |
| * calling hvc_poll() who determines whether a console adapter support |
| * interrupts. |
| */ |
| static int khvcd(void *unused) |
| { |
| int poll_mask; |
| struct hvc_struct *hp; |
| |
| set_freezable(); |
| do { |
| poll_mask = 0; |
| hvc_kicked = 0; |
| try_to_freeze(); |
| wmb(); |
| if (!cpus_are_in_xmon()) { |
| mutex_lock(&hvc_structs_mutex); |
| list_for_each_entry(hp, &hvc_structs, next) { |
| poll_mask |= __hvc_poll(hp, true); |
| cond_resched(); |
| } |
| mutex_unlock(&hvc_structs_mutex); |
| } else |
| poll_mask |= HVC_POLL_READ; |
| if (hvc_kicked) |
| continue; |
| set_current_state(TASK_INTERRUPTIBLE); |
| if (!hvc_kicked) { |
| if (poll_mask == 0) |
| schedule(); |
| else { |
| unsigned long j_timeout; |
| |
| if (timeout < MAX_TIMEOUT) |
| timeout += (timeout >> 6) + 1; |
| |
| /* |
| * We don't use msleep_interruptible otherwise |
| * "kick" will fail to wake us up |
| */ |
| j_timeout = msecs_to_jiffies(timeout) + 1; |
| schedule_timeout_interruptible(j_timeout); |
| } |
| } |
| __set_current_state(TASK_RUNNING); |
| } while (!kthread_should_stop()); |
| |
| return 0; |
| } |
| |
| static int hvc_tiocmget(struct tty_struct *tty) |
| { |
| struct hvc_struct *hp = tty->driver_data; |
| |
| if (!hp || !hp->ops->tiocmget) |
| return -EINVAL; |
| return hp->ops->tiocmget(hp); |
| } |
| |
| static int hvc_tiocmset(struct tty_struct *tty, |
| unsigned int set, unsigned int clear) |
| { |
| struct hvc_struct *hp = tty->driver_data; |
| |
| if (!hp || !hp->ops->tiocmset) |
| return -EINVAL; |
| return hp->ops->tiocmset(hp, set, clear); |
| } |
| |
| #ifdef CONFIG_CONSOLE_POLL |
| static int hvc_poll_init(struct tty_driver *driver, int line, char *options) |
| { |
| return 0; |
| } |
| |
| static int hvc_poll_get_char(struct tty_driver *driver, int line) |
| { |
| struct tty_struct *tty = driver->ttys[0]; |
| struct hvc_struct *hp = tty->driver_data; |
| int n; |
| char ch; |
| |
| n = hp->ops->get_chars(hp->vtermno, &ch, 1); |
| |
| if (n <= 0) |
| return NO_POLL_CHAR; |
| |
| return ch; |
| } |
| |
| static void hvc_poll_put_char(struct tty_driver *driver, int line, char ch) |
| { |
| struct tty_struct *tty = driver->ttys[0]; |
| struct hvc_struct *hp = tty->driver_data; |
| int n; |
| |
| do { |
| n = hp->ops->put_chars(hp->vtermno, &ch, 1); |
| } while (n <= 0); |
| } |
| #endif |
| |
| static const struct tty_operations hvc_ops = { |
| .install = hvc_install, |
| .open = hvc_open, |
| .close = hvc_close, |
| .cleanup = hvc_cleanup, |
| .write = hvc_write, |
| .hangup = hvc_hangup, |
| .unthrottle = hvc_unthrottle, |
| .write_room = hvc_write_room, |
| .chars_in_buffer = hvc_chars_in_buffer, |
| .tiocmget = hvc_tiocmget, |
| .tiocmset = hvc_tiocmset, |
| #ifdef CONFIG_CONSOLE_POLL |
| .poll_init = hvc_poll_init, |
| .poll_get_char = hvc_poll_get_char, |
| .poll_put_char = hvc_poll_put_char, |
| #endif |
| }; |
| |
| static const struct tty_port_operations hvc_port_ops = { |
| .destruct = hvc_port_destruct, |
| }; |
| |
| struct hvc_struct *hvc_alloc(uint32_t vtermno, int data, |
| const struct hv_ops *ops, |
| int outbuf_size) |
| { |
| struct hvc_struct *hp; |
| int i; |
| |
| /* We wait until a driver actually comes along */ |
| if (atomic_inc_not_zero(&hvc_needs_init)) { |
| int err = hvc_init(); |
| if (err) |
| return ERR_PTR(err); |
| } |
| |
| hp = kzalloc(ALIGN(sizeof(*hp), sizeof(long)) + outbuf_size, |
| GFP_KERNEL); |
| if (!hp) |
| return ERR_PTR(-ENOMEM); |
| |
| hp->vtermno = vtermno; |
| hp->data = data; |
| hp->ops = ops; |
| hp->outbuf_size = outbuf_size; |
| hp->outbuf = &((char *)hp)[ALIGN(sizeof(*hp), sizeof(long))]; |
| |
| tty_port_init(&hp->port); |
| hp->port.ops = &hvc_port_ops; |
| |
| INIT_WORK(&hp->tty_resize, hvc_set_winsz); |
| spin_lock_init(&hp->lock); |
| mutex_lock(&hvc_structs_mutex); |
| |
| /* |
| * find index to use: |
| * see if this vterm id matches one registered for console. |
| */ |
| for (i=0; i < MAX_NR_HVC_CONSOLES; i++) |
| if (vtermnos[i] == hp->vtermno && |
| cons_ops[i] == hp->ops) |
| break; |
| |
| /* no matching slot, just use a counter */ |
| if (i >= MAX_NR_HVC_CONSOLES) |
| i = ++last_hvc; |
| |
| hp->index = i; |
| cons_ops[i] = ops; |
| vtermnos[i] = vtermno; |
| |
| list_add_tail(&(hp->next), &hvc_structs); |
| mutex_unlock(&hvc_structs_mutex); |
| |
| /* check if we need to re-register the kernel console */ |
| hvc_check_console(i); |
| |
| return hp; |
| } |
| EXPORT_SYMBOL_GPL(hvc_alloc); |
| |
| int hvc_remove(struct hvc_struct *hp) |
| { |
| unsigned long flags; |
| struct tty_struct *tty; |
| |
| tty = tty_port_tty_get(&hp->port); |
| |
| console_lock(); |
| spin_lock_irqsave(&hp->lock, flags); |
| if (hp->index < MAX_NR_HVC_CONSOLES) { |
| vtermnos[hp->index] = -1; |
| cons_ops[hp->index] = NULL; |
| } |
| |
| /* Don't whack hp->irq because tty_hangup() will need to free the irq. */ |
| |
| spin_unlock_irqrestore(&hp->lock, flags); |
| console_unlock(); |
| |
| /* |
| * We 'put' the instance that was grabbed when the kref instance |
| * was initialized using kref_init(). Let the last holder of this |
| * kref cause it to be removed, which will probably be the tty_vhangup |
| * below. |
| */ |
| tty_port_put(&hp->port); |
| |
| /* |
| * This function call will auto chain call hvc_hangup. |
| */ |
| if (tty) { |
| tty_vhangup(tty); |
| tty_kref_put(tty); |
| } |
| return 0; |
| } |
| EXPORT_SYMBOL_GPL(hvc_remove); |
| |
| /* Driver initialization: called as soon as someone uses hvc_alloc(). */ |
| static int hvc_init(void) |
| { |
| struct tty_driver *drv; |
| int err; |
| |
| /* We need more than hvc_count adapters due to hotplug additions. */ |
| drv = alloc_tty_driver(HVC_ALLOC_TTY_ADAPTERS); |
| if (!drv) { |
| err = -ENOMEM; |
| goto out; |
| } |
| |
| drv->driver_name = "hvc"; |
| drv->name = "hvc"; |
| drv->major = HVC_MAJOR; |
| drv->minor_start = HVC_MINOR; |
| drv->type = TTY_DRIVER_TYPE_SYSTEM; |
| drv->init_termios = tty_std_termios; |
| drv->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_RESET_TERMIOS; |
| tty_set_operations(drv, &hvc_ops); |
| |
| /* Always start the kthread because there can be hotplug vty adapters |
| * added later. */ |
| hvc_task = kthread_run(khvcd, NULL, "khvcd"); |
| if (IS_ERR(hvc_task)) { |
| printk(KERN_ERR "Couldn't create kthread for console.\n"); |
| err = PTR_ERR(hvc_task); |
| goto put_tty; |
| } |
| |
| err = tty_register_driver(drv); |
| if (err) { |
| printk(KERN_ERR "Couldn't register hvc console driver\n"); |
| goto stop_thread; |
| } |
| |
| /* |
| * Make sure tty is fully registered before allowing it to be |
| * found by hvc_console_device. |
| */ |
| smp_mb(); |
| hvc_driver = drv; |
| return 0; |
| |
| stop_thread: |
| kthread_stop(hvc_task); |
| hvc_task = NULL; |
| put_tty: |
| put_tty_driver(drv); |
| out: |
| return err; |
| } |