tty: move hvc drivers to drivers/tty/hvc/
As requested by Arnd Bergmann, the hvc drivers are now moved to the drivers/tty/hvc/ directory. The virtio_console.c driver was also moved, as it required the hvc_console.h file to be able to be built, and it really is a hvc driver. Cc: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Greg Kroah-Hartman
914
drivers/tty/hvc/hvc_console.c
Normal file
914
drivers/tty/hvc/hvc_console.c
Normal file
@@ -0,0 +1,914 @@
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/*
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* Copyright (C) 2001 Anton Blanchard <anton@au.ibm.com>, IBM
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* Copyright (C) 2001 Paul Mackerras <paulus@au.ibm.com>, IBM
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* Copyright (C) 2004 Benjamin Herrenschmidt <benh@kernel.crashing.org>, IBM Corp.
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* Copyright (C) 2004 IBM Corporation
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*
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* Additional Author(s):
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* Ryan S. Arnold <rsa@us.ibm.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#include <linux/console.h>
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#include <linux/cpumask.h>
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#include <linux/init.h>
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#include <linux/kbd_kern.h>
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#include <linux/kernel.h>
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#include <linux/kthread.h>
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#include <linux/list.h>
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#include <linux/module.h>
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#include <linux/major.h>
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#include <linux/sysrq.h>
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#include <linux/tty.h>
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#include <linux/tty_flip.h>
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#include <linux/sched.h>
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#include <linux/spinlock.h>
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#include <linux/delay.h>
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#include <linux/freezer.h>
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#include <linux/slab.h>
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#include <asm/uaccess.h>
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#include "hvc_console.h"
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#define HVC_MAJOR 229
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#define HVC_MINOR 0
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/*
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* Wait this long per iteration while trying to push buffered data to the
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* hypervisor before allowing the tty to complete a close operation.
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*/
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#define HVC_CLOSE_WAIT (HZ/100) /* 1/10 of a second */
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/*
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* These sizes are most efficient for vio, because they are the
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* native transfer size. We could make them selectable in the
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* future to better deal with backends that want other buffer sizes.
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*/
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#define N_OUTBUF 16
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#define N_INBUF 16
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#define __ALIGNED__ __attribute__((__aligned__(sizeof(long))))
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static struct tty_driver *hvc_driver;
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static struct task_struct *hvc_task;
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/* Picks up late kicks after list walk but before schedule() */
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static int hvc_kicked;
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static int hvc_init(void);
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#ifdef CONFIG_MAGIC_SYSRQ
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static int sysrq_pressed;
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#endif
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/* dynamic list of hvc_struct instances */
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static LIST_HEAD(hvc_structs);
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/*
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* Protect the list of hvc_struct instances from inserts and removals during
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* list traversal.
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*/
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static DEFINE_SPINLOCK(hvc_structs_lock);
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/*
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* This value is used to assign a tty->index value to a hvc_struct based
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* upon order of exposure via hvc_probe(), when we can not match it to
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* a console candidate registered with hvc_instantiate().
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*/
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static int last_hvc = -1;
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/*
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* Do not call this function with either the hvc_structs_lock or the hvc_struct
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* lock held. If successful, this function increments the kref reference
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* count against the target hvc_struct so it should be released when finished.
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*/
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static struct hvc_struct *hvc_get_by_index(int index)
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{
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struct hvc_struct *hp;
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unsigned long flags;
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spin_lock(&hvc_structs_lock);
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list_for_each_entry(hp, &hvc_structs, next) {
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spin_lock_irqsave(&hp->lock, flags);
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if (hp->index == index) {
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kref_get(&hp->kref);
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spin_unlock_irqrestore(&hp->lock, flags);
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spin_unlock(&hvc_structs_lock);
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return hp;
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}
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spin_unlock_irqrestore(&hp->lock, flags);
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}
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hp = NULL;
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spin_unlock(&hvc_structs_lock);
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return hp;
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}
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/*
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* Initial console vtermnos for console API usage prior to full console
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* initialization. Any vty adapter outside this range will not have usable
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* console interfaces but can still be used as a tty device. This has to be
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* static because kmalloc will not work during early console init.
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*/
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static const struct hv_ops *cons_ops[MAX_NR_HVC_CONSOLES];
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static uint32_t vtermnos[MAX_NR_HVC_CONSOLES] =
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{[0 ... MAX_NR_HVC_CONSOLES - 1] = -1};
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/*
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* Console APIs, NOT TTY. These APIs are available immediately when
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* hvc_console_setup() finds adapters.
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*/
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static void hvc_console_print(struct console *co, const char *b,
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unsigned count)
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{
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char c[N_OUTBUF] __ALIGNED__;
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unsigned i = 0, n = 0;
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int r, donecr = 0, index = co->index;
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/* Console access attempt outside of acceptable console range. */
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if (index >= MAX_NR_HVC_CONSOLES)
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return;
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/* This console adapter was removed so it is not usable. */
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if (vtermnos[index] == -1)
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return;
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while (count > 0 || i > 0) {
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if (count > 0 && i < sizeof(c)) {
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if (b[n] == '\n' && !donecr) {
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c[i++] = '\r';
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donecr = 1;
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} else {
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c[i++] = b[n++];
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donecr = 0;
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--count;
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}
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} else {
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r = cons_ops[index]->put_chars(vtermnos[index], c, i);
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if (r <= 0) {
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/* throw away chars on error */
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i = 0;
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} else if (r > 0) {
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i -= r;
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if (i > 0)
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memmove(c, c+r, i);
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}
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}
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}
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}
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static struct tty_driver *hvc_console_device(struct console *c, int *index)
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{
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if (vtermnos[c->index] == -1)
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return NULL;
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*index = c->index;
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return hvc_driver;
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}
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static int __init hvc_console_setup(struct console *co, char *options)
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{
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if (co->index < 0 || co->index >= MAX_NR_HVC_CONSOLES)
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return -ENODEV;
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if (vtermnos[co->index] == -1)
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return -ENODEV;
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return 0;
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}
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static struct console hvc_console = {
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.name = "hvc",
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.write = hvc_console_print,
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.device = hvc_console_device,
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.setup = hvc_console_setup,
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.flags = CON_PRINTBUFFER,
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.index = -1,
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};
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/*
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* Early console initialization. Precedes driver initialization.
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*
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* (1) we are first, and the user specified another driver
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* -- index will remain -1
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* (2) we are first and the user specified no driver
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* -- index will be set to 0, then we will fail setup.
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* (3) we are first and the user specified our driver
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* -- index will be set to user specified driver, and we will fail
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* (4) we are after driver, and this initcall will register us
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* -- if the user didn't specify a driver then the console will match
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*
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* Note that for cases 2 and 3, we will match later when the io driver
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* calls hvc_instantiate() and call register again.
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*/
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static int __init hvc_console_init(void)
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{
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register_console(&hvc_console);
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return 0;
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}
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console_initcall(hvc_console_init);
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/* callback when the kboject ref count reaches zero. */
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static void destroy_hvc_struct(struct kref *kref)
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{
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struct hvc_struct *hp = container_of(kref, struct hvc_struct, kref);
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unsigned long flags;
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spin_lock(&hvc_structs_lock);
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spin_lock_irqsave(&hp->lock, flags);
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list_del(&(hp->next));
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spin_unlock_irqrestore(&hp->lock, flags);
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spin_unlock(&hvc_structs_lock);
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kfree(hp);
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}
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/*
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* hvc_instantiate() is an early console discovery method which locates
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* consoles * prior to the vio subsystem discovering them. Hotplugged
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* vty adapters do NOT get an hvc_instantiate() callback since they
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* appear after early console init.
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*/
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int hvc_instantiate(uint32_t vtermno, int index, const struct hv_ops *ops)
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{
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struct hvc_struct *hp;
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if (index < 0 || index >= MAX_NR_HVC_CONSOLES)
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return -1;
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if (vtermnos[index] != -1)
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return -1;
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/* make sure no no tty has been registered in this index */
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hp = hvc_get_by_index(index);
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if (hp) {
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kref_put(&hp->kref, destroy_hvc_struct);
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return -1;
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}
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vtermnos[index] = vtermno;
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cons_ops[index] = ops;
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/* reserve all indices up to and including this index */
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if (last_hvc < index)
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last_hvc = index;
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/* if this index is what the user requested, then register
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* now (setup won't fail at this point). It's ok to just
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* call register again if previously .setup failed.
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*/
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if (index == hvc_console.index)
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register_console(&hvc_console);
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return 0;
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}
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EXPORT_SYMBOL_GPL(hvc_instantiate);
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/* Wake the sleeping khvcd */
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void hvc_kick(void)
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{
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hvc_kicked = 1;
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wake_up_process(hvc_task);
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}
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EXPORT_SYMBOL_GPL(hvc_kick);
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static void hvc_unthrottle(struct tty_struct *tty)
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{
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hvc_kick();
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}
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/*
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* The TTY interface won't be used until after the vio layer has exposed the vty
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* adapter to the kernel.
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*/
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static int hvc_open(struct tty_struct *tty, struct file * filp)
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{
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struct hvc_struct *hp;
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unsigned long flags;
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int rc = 0;
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/* Auto increments kref reference if found. */
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if (!(hp = hvc_get_by_index(tty->index)))
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return -ENODEV;
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spin_lock_irqsave(&hp->lock, flags);
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/* Check and then increment for fast path open. */
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if (hp->count++ > 0) {
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tty_kref_get(tty);
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spin_unlock_irqrestore(&hp->lock, flags);
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hvc_kick();
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return 0;
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} /* else count == 0 */
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tty->driver_data = hp;
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hp->tty = tty_kref_get(tty);
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spin_unlock_irqrestore(&hp->lock, flags);
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if (hp->ops->notifier_add)
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rc = hp->ops->notifier_add(hp, hp->data);
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/*
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* If the notifier fails we return an error. The tty layer
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* will call hvc_close() after a failed open but we don't want to clean
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* up there so we'll clean up here and clear out the previously set
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* tty fields and return the kref reference.
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*/
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if (rc) {
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spin_lock_irqsave(&hp->lock, flags);
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hp->tty = NULL;
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spin_unlock_irqrestore(&hp->lock, flags);
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tty_kref_put(tty);
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tty->driver_data = NULL;
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kref_put(&hp->kref, destroy_hvc_struct);
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printk(KERN_ERR "hvc_open: request_irq failed with rc %d.\n", rc);
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}
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/* Force wakeup of the polling thread */
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hvc_kick();
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return rc;
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}
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static void hvc_close(struct tty_struct *tty, struct file * filp)
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{
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struct hvc_struct *hp;
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unsigned long flags;
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if (tty_hung_up_p(filp))
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return;
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/*
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* No driver_data means that this close was issued after a failed
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* hvc_open by the tty layer's release_dev() function and we can just
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* exit cleanly because the kref reference wasn't made.
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*/
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if (!tty->driver_data)
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return;
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hp = tty->driver_data;
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spin_lock_irqsave(&hp->lock, flags);
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if (--hp->count == 0) {
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/* We are done with the tty pointer now. */
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hp->tty = NULL;
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spin_unlock_irqrestore(&hp->lock, flags);
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if (hp->ops->notifier_del)
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hp->ops->notifier_del(hp, hp->data);
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/* cancel pending tty resize work */
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cancel_work_sync(&hp->tty_resize);
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/*
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* Chain calls chars_in_buffer() and returns immediately if
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* there is no buffered data otherwise sleeps on a wait queue
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* waking periodically to check chars_in_buffer().
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*/
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tty_wait_until_sent(tty, HVC_CLOSE_WAIT);
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} else {
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if (hp->count < 0)
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printk(KERN_ERR "hvc_close %X: oops, count is %d\n",
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hp->vtermno, hp->count);
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spin_unlock_irqrestore(&hp->lock, flags);
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}
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tty_kref_put(tty);
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kref_put(&hp->kref, destroy_hvc_struct);
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}
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static void hvc_hangup(struct tty_struct *tty)
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{
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struct hvc_struct *hp = tty->driver_data;
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unsigned long flags;
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int temp_open_count;
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if (!hp)
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return;
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/* cancel pending tty resize work */
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cancel_work_sync(&hp->tty_resize);
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spin_lock_irqsave(&hp->lock, flags);
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/*
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* The N_TTY line discipline has problems such that in a close vs
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* open->hangup case this can be called after the final close so prevent
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* that from happening for now.
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*/
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if (hp->count <= 0) {
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spin_unlock_irqrestore(&hp->lock, flags);
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return;
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}
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temp_open_count = hp->count;
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hp->count = 0;
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hp->n_outbuf = 0;
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hp->tty = NULL;
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spin_unlock_irqrestore(&hp->lock, flags);
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if (hp->ops->notifier_hangup)
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hp->ops->notifier_hangup(hp, hp->data);
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while(temp_open_count) {
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--temp_open_count;
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tty_kref_put(tty);
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kref_put(&hp->kref, destroy_hvc_struct);
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}
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}
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/*
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* Push buffered characters whether they were just recently buffered or waiting
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* on a blocked hypervisor. Call this function with hp->lock held.
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*/
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static int hvc_push(struct hvc_struct *hp)
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{
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int n;
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n = hp->ops->put_chars(hp->vtermno, hp->outbuf, hp->n_outbuf);
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if (n <= 0) {
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if (n == 0) {
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hp->do_wakeup = 1;
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return 0;
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}
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/* throw away output on error; this happens when
|
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there is no session connected to the vterm. */
|
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hp->n_outbuf = 0;
|
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} else
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hp->n_outbuf -= n;
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if (hp->n_outbuf > 0)
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memmove(hp->outbuf, hp->outbuf + n, hp->n_outbuf);
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else
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hp->do_wakeup = 1;
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return n;
|
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}
|
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|
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static int hvc_write(struct tty_struct *tty, const unsigned char *buf, int count)
|
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{
|
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struct hvc_struct *hp = tty->driver_data;
|
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unsigned long flags;
|
||||
int rsize, written = 0;
|
||||
|
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/* This write was probably executed during a tty close. */
|
||||
if (!hp)
|
||||
return -EPIPE;
|
||||
|
||||
if (hp->count <= 0)
|
||||
return -EIO;
|
||||
|
||||
spin_lock_irqsave(&hp->lock, flags);
|
||||
|
||||
/* Push pending writes */
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if (hp->n_outbuf > 0)
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hvc_push(hp);
|
||||
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||||
while (count > 0 && (rsize = hp->outbuf_size - hp->n_outbuf) > 0) {
|
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if (rsize > count)
|
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rsize = count;
|
||||
memcpy(hp->outbuf + hp->n_outbuf, buf, rsize);
|
||||
count -= rsize;
|
||||
buf += rsize;
|
||||
hp->n_outbuf += rsize;
|
||||
written += rsize;
|
||||
hvc_push(hp);
|
||||
}
|
||||
spin_unlock_irqrestore(&hp->lock, flags);
|
||||
|
||||
/*
|
||||
* 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);
|
||||
|
||||
spin_lock_irqsave(&hp->lock, hvc_flags);
|
||||
if (!hp->tty) {
|
||||
spin_unlock_irqrestore(&hp->lock, hvc_flags);
|
||||
return;
|
||||
}
|
||||
ws = hp->ws;
|
||||
tty = tty_kref_get(hp->tty);
|
||||
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 -1;
|
||||
|
||||
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;
|
||||
|
||||
#define HVC_POLL_READ 0x00000001
|
||||
#define HVC_POLL_WRITE 0x00000002
|
||||
|
||||
int hvc_poll(struct hvc_struct *hp)
|
||||
{
|
||||
struct tty_struct *tty;
|
||||
int i, n, 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;
|
||||
}
|
||||
|
||||
/* No tty attached, just skip */
|
||||
tty = tty_kref_get(hp->tty);
|
||||
if (tty == NULL)
|
||||
goto bail;
|
||||
|
||||
/* Now check if we can get data (are we throttled ?) */
|
||||
if (test_bit(TTY_THROTTLED, &tty->flags))
|
||||
goto throttled;
|
||||
|
||||
/* 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 data if any */
|
||||
for (;;) {
|
||||
int count = tty_buffer_request_room(tty, N_INBUF);
|
||||
|
||||
/* If flip is full, just reschedule a later read */
|
||||
if (count == 0) {
|
||||
poll_mask |= HVC_POLL_READ;
|
||||
break;
|
||||
}
|
||||
|
||||
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;
|
||||
}
|
||||
break;
|
||||
}
|
||||
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(tty, buf[i], 0);
|
||||
}
|
||||
|
||||
read_total += n;
|
||||
}
|
||||
throttled:
|
||||
/* 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(tty);
|
||||
}
|
||||
if (tty)
|
||||
tty_kref_put(tty);
|
||||
|
||||
return poll_mask;
|
||||
}
|
||||
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()) {
|
||||
spin_lock(&hvc_structs_lock);
|
||||
list_for_each_entry(hp, &hvc_structs, next) {
|
||||
poll_mask |= hvc_poll(hp);
|
||||
}
|
||||
spin_unlock(&hvc_structs_lock);
|
||||
} else
|
||||
poll_mask |= HVC_POLL_READ;
|
||||
if (hvc_kicked)
|
||||
continue;
|
||||
set_current_state(TASK_INTERRUPTIBLE);
|
||||
if (!hvc_kicked) {
|
||||
if (poll_mask == 0)
|
||||
schedule();
|
||||
else {
|
||||
if (timeout < MAX_TIMEOUT)
|
||||
timeout += (timeout >> 6) + 1;
|
||||
|
||||
msleep_interruptible(timeout);
|
||||
}
|
||||
}
|
||||
__set_current_state(TASK_RUNNING);
|
||||
} while (!kthread_should_stop());
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
static const struct tty_operations hvc_ops = {
|
||||
.open = hvc_open,
|
||||
.close = hvc_close,
|
||||
.write = hvc_write,
|
||||
.hangup = hvc_hangup,
|
||||
.unthrottle = hvc_unthrottle,
|
||||
.write_room = hvc_write_room,
|
||||
.chars_in_buffer = hvc_chars_in_buffer,
|
||||
};
|
||||
|
||||
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 (!hvc_driver) {
|
||||
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))];
|
||||
|
||||
kref_init(&hp->kref);
|
||||
|
||||
INIT_WORK(&hp->tty_resize, hvc_set_winsz);
|
||||
spin_lock_init(&hp->lock);
|
||||
spin_lock(&hvc_structs_lock);
|
||||
|
||||
/*
|
||||
* 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;
|
||||
|
||||
list_add_tail(&(hp->next), &hvc_structs);
|
||||
spin_unlock(&hvc_structs_lock);
|
||||
|
||||
return hp;
|
||||
}
|
||||
EXPORT_SYMBOL_GPL(hvc_alloc);
|
||||
|
||||
int hvc_remove(struct hvc_struct *hp)
|
||||
{
|
||||
unsigned long flags;
|
||||
struct tty_struct *tty;
|
||||
|
||||
spin_lock_irqsave(&hp->lock, flags);
|
||||
tty = tty_kref_get(hp->tty);
|
||||
|
||||
if (hp->index < MAX_NR_HVC_CONSOLES)
|
||||
vtermnos[hp->index] = -1;
|
||||
|
||||
/* Don't whack hp->irq because tty_hangup() will need to free the irq. */
|
||||
|
||||
spin_unlock_irqrestore(&hp->lock, flags);
|
||||
|
||||
/*
|
||||
* 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.
|
||||
*/
|
||||
kref_put(&hp->kref, destroy_hvc_struct);
|
||||
|
||||
/*
|
||||
* 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->owner = THIS_MODULE;
|
||||
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;
|
||||
}
|
||||
|
||||
/* This isn't particularly necessary due to this being a console driver
|
||||
* but it is nice to be thorough.
|
||||
*/
|
||||
static void __exit hvc_exit(void)
|
||||
{
|
||||
if (hvc_driver) {
|
||||
kthread_stop(hvc_task);
|
||||
|
||||
tty_unregister_driver(hvc_driver);
|
||||
/* return tty_struct instances allocated in hvc_init(). */
|
||||
put_tty_driver(hvc_driver);
|
||||
unregister_console(&hvc_console);
|
||||
}
|
||||
}
|
||||
module_exit(hvc_exit);
|
||||
Reference in New Issue
Block a user