linux/arch/um/drivers/stdio_console.c
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   1// SPDX-License-Identifier: GPL-2.0
   2/* 
   3 * Copyright (C) 2000, 2001 Jeff Dike (jdike@karaya.com)
   4 */
   5
   6#include <linux/posix_types.h>
   7#include <linux/tty.h>
   8#include <linux/tty_flip.h>
   9#include <linux/types.h>
  10#include <linux/major.h>
  11#include <linux/kdev_t.h>
  12#include <linux/console.h>
  13#include <linux/string.h>
  14#include <linux/sched.h>
  15#include <linux/list.h>
  16#include <linux/init.h>
  17#include <linux/interrupt.h>
  18#include <linux/slab.h>
  19#include <linux/hardirq.h>
  20#include <asm/current.h>
  21#include <asm/irq.h>
  22#include "stdio_console.h"
  23#include "chan.h"
  24#include <irq_user.h>
  25#include "mconsole_kern.h"
  26#include <init.h>
  27
  28#define MAX_TTYS (16)
  29
  30static void stdio_announce(char *dev_name, int dev)
  31{
  32        printk(KERN_INFO "Virtual console %d assigned device '%s'\n", dev,
  33               dev_name);
  34}
  35
  36/* Almost const, except that xterm_title may be changed in an initcall */
  37static struct chan_opts opts = {
  38        .announce       = stdio_announce,
  39        .xterm_title    = "Virtual Console #%d",
  40        .raw            = 1,
  41};
  42
  43static int con_config(char *str, char **error_out);
  44static int con_get_config(char *dev, char *str, int size, char **error_out);
  45static int con_remove(int n, char **con_remove);
  46
  47
  48/* Const, except for .mc.list */
  49static struct line_driver driver = {
  50        .name                   = "UML console",
  51        .device_name            = "tty",
  52        .major                  = TTY_MAJOR,
  53        .minor_start            = 0,
  54        .type                   = TTY_DRIVER_TYPE_CONSOLE,
  55        .subtype                = SYSTEM_TYPE_CONSOLE,
  56        .read_irq               = CONSOLE_IRQ,
  57        .read_irq_name          = "console",
  58        .write_irq              = CONSOLE_WRITE_IRQ,
  59        .write_irq_name         = "console-write",
  60        .mc  = {
  61                .list           = LIST_HEAD_INIT(driver.mc.list),
  62                .name           = "con",
  63                .config         = con_config,
  64                .get_config     = con_get_config,
  65                .id             = line_id,
  66                .remove         = con_remove,
  67        },
  68};
  69
  70/* The array is initialized by line_init, at initcall time.  The
  71 * elements are locked individually as needed.
  72 */
  73static char *vt_conf[MAX_TTYS];
  74static char *def_conf;
  75static struct line vts[MAX_TTYS];
  76
  77static int con_config(char *str, char **error_out)
  78{
  79        return line_config(vts, ARRAY_SIZE(vts), str, &opts, error_out);
  80}
  81
  82static int con_get_config(char *dev, char *str, int size, char **error_out)
  83{
  84        return line_get_config(dev, vts, ARRAY_SIZE(vts), str, size, error_out);
  85}
  86
  87static int con_remove(int n, char **error_out)
  88{
  89        return line_remove(vts, ARRAY_SIZE(vts), n, error_out);
  90}
  91
  92/* Set in an initcall, checked in an exitcall */
  93static int con_init_done = 0;
  94
  95static int con_install(struct tty_driver *driver, struct tty_struct *tty)
  96{
  97        return line_install(driver, tty, &vts[tty->index]);
  98}
  99
 100static const struct tty_operations console_ops = {
 101        .open                   = line_open,
 102        .install                = con_install,
 103        .close                  = line_close,
 104        .write                  = line_write,
 105        .write_room             = line_write_room,
 106        .chars_in_buffer        = line_chars_in_buffer,
 107        .flush_buffer           = line_flush_buffer,
 108        .flush_chars            = line_flush_chars,
 109        .throttle               = line_throttle,
 110        .unthrottle             = line_unthrottle,
 111        .hangup                 = line_hangup,
 112};
 113
 114static void uml_console_write(struct console *console, const char *string,
 115                              unsigned len)
 116{
 117        struct line *line = &vts[console->index];
 118        unsigned long flags;
 119
 120        spin_lock_irqsave(&line->lock, flags);
 121        console_write_chan(line->chan_out, string, len);
 122        spin_unlock_irqrestore(&line->lock, flags);
 123}
 124
 125static struct tty_driver *uml_console_device(struct console *c, int *index)
 126{
 127        *index = c->index;
 128        return driver.driver;
 129}
 130
 131static int uml_console_setup(struct console *co, char *options)
 132{
 133        struct line *line = &vts[co->index];
 134
 135        return console_open_chan(line, co);
 136}
 137
 138/* No locking for register_console call - relies on single-threaded initcalls */
 139static struct console stdiocons = {
 140        .name           = "tty",
 141        .write          = uml_console_write,
 142        .device         = uml_console_device,
 143        .setup          = uml_console_setup,
 144        .flags          = CON_PRINTBUFFER|CON_ANYTIME,
 145        .index          = -1,
 146};
 147
 148static int stdio_init(void)
 149{
 150        char *new_title;
 151        int err;
 152        int i;
 153
 154        err = register_lines(&driver, &console_ops, vts,
 155                                        ARRAY_SIZE(vts));
 156        if (err)
 157                return err;
 158
 159        printk(KERN_INFO "Initialized stdio console driver\n");
 160
 161        new_title = add_xterm_umid(opts.xterm_title);
 162        if(new_title != NULL)
 163                opts.xterm_title = new_title;
 164
 165        for (i = 0; i < MAX_TTYS; i++) {
 166                char *error;
 167                char *s = vt_conf[i];
 168                if (!s)
 169                        s = def_conf;
 170                if (!s)
 171                        s = i ? CONFIG_CON_CHAN : CONFIG_CON_ZERO_CHAN;
 172                if (setup_one_line(vts, i, s, &opts, &error))
 173                        printk(KERN_ERR "setup_one_line failed for "
 174                               "device %d : %s\n", i, error);
 175        }
 176
 177        con_init_done = 1;
 178        register_console(&stdiocons);
 179        return 0;
 180}
 181late_initcall(stdio_init);
 182
 183static void console_exit(void)
 184{
 185        if (!con_init_done)
 186                return;
 187        close_lines(vts, ARRAY_SIZE(vts));
 188}
 189__uml_exitcall(console_exit);
 190
 191static int console_chan_setup(char *str)
 192{
 193        if (!strncmp(str, "sole=", 5))  /* console= option specifies tty */
 194                return 0;
 195
 196        line_setup(vt_conf, MAX_TTYS, &def_conf, str, "console");
 197        return 1;
 198}
 199__setup("con", console_chan_setup);
 200__channel_help(console_chan_setup, "con");
 201