Linux kernel & device driver programming

Cross-Referenced Linux and Device Driver Code

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Version: [ 2.6.11.8 ] [ 2.6.25 ] [ 2.6.25.8 ] [ 2.6.31.13 ] Architecture: [ i386 ]
  1 /* 
  2  * Copyright (C) 2000, 2001 Jeff Dike (jdike@karaya.com)
  3  * Licensed under the GPL
  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 "line.h"
 24 #include "chan_kern.h"
 25 #include "irq_user.h"
 26 #include "mconsole_kern.h"
 27 #include "init.h"
 28 
 29 #define MAX_TTYS (16)
 30 
 31 /* Referenced only by tty_driver below - presumably it's locked correctly
 32  * by the tty driver.
 33  */
 34 
 35 static struct tty_driver *console_driver;
 36 
 37 static void stdio_announce(char *dev_name, int dev)
 38 {
 39         printk(KERN_INFO "Virtual console %d assigned device '%s'\n", dev,
 40                dev_name);
 41 }
 42 
 43 /* Almost const, except that xterm_title may be changed in an initcall */
 44 static struct chan_opts opts = {
 45         .announce       = stdio_announce,
 46         .xterm_title    = "Virtual Console #%d",
 47         .raw            = 1,
 48 };
 49 
 50 static int con_config(char *str, char **error_out);
 51 static int con_get_config(char *dev, char *str, int size, char **error_out);
 52 static int con_remove(int n, char **con_remove);
 53 
 54 
 55 /* Const, except for .mc.list */
 56 static struct line_driver driver = {
 57         .name                   = "UML console",
 58         .device_name            = "tty",
 59         .major                  = TTY_MAJOR,
 60         .minor_start            = 0,
 61         .type                   = TTY_DRIVER_TYPE_CONSOLE,
 62         .subtype                = SYSTEM_TYPE_CONSOLE,
 63         .read_irq               = CONSOLE_IRQ,
 64         .read_irq_name          = "console",
 65         .write_irq              = CONSOLE_WRITE_IRQ,
 66         .write_irq_name         = "console-write",
 67         .mc  = {
 68                 .list           = LIST_HEAD_INIT(driver.mc.list),
 69                 .name           = "con",
 70                 .config         = con_config,
 71                 .get_config     = con_get_config,
 72                 .id             = line_id,
 73                 .remove         = con_remove,
 74         },
 75 };
 76 
 77 /* The array is initialized by line_init, at initcall time.  The
 78  * elements are locked individually as needed.
 79  */
 80 static struct line vts[MAX_TTYS] = { LINE_INIT(CONFIG_CON_ZERO_CHAN, &driver),
 81                                      [ 1 ... MAX_TTYS - 1 ] =
 82                                      LINE_INIT(CONFIG_CON_CHAN, &driver) };
 83 
 84 static int con_config(char *str, char **error_out)
 85 {
 86         return line_config(vts, ARRAY_SIZE(vts), str, &opts, error_out);
 87 }
 88 
 89 static int con_get_config(char *dev, char *str, int size, char **error_out)
 90 {
 91         return line_get_config(dev, vts, ARRAY_SIZE(vts), str, size, error_out);
 92 }
 93 
 94 static int con_remove(int n, char **error_out)
 95 {
 96         return line_remove(vts, ARRAY_SIZE(vts), n, error_out);
 97 }
 98 
 99 static int con_open(struct tty_struct *tty, struct file *filp)
100 {
101         int err = line_open(vts, tty);
102         if (err)
103                 printk(KERN_ERR "Failed to open console %d, err = %d\n",
104                        tty->index, err);
105 
106         return err;
107 }
108 
109 /* Set in an initcall, checked in an exitcall */
110 static int con_init_done = 0;
111 
112 static const struct tty_operations console_ops = {
113         .open                   = con_open,
114         .close                  = line_close,
115         .write                  = line_write,
116         .put_char               = line_put_char,
117         .write_room             = line_write_room,
118         .chars_in_buffer        = line_chars_in_buffer,
119         .flush_buffer           = line_flush_buffer,
120         .flush_chars            = line_flush_chars,
121         .set_termios            = line_set_termios,
122         .ioctl                  = line_ioctl,
123         .throttle               = line_throttle,
124         .unthrottle             = line_unthrottle,
125 };
126 
127 static void uml_console_write(struct console *console, const char *string,
128                               unsigned len)
129 {
130         struct line *line = &vts[console->index];
131         unsigned long flags;
132 
133         spin_lock_irqsave(&line->lock, flags);
134         console_write_chan(&line->chan_list, string, len);
135         spin_unlock_irqrestore(&line->lock, flags);
136 }
137 
138 static struct tty_driver *uml_console_device(struct console *c, int *index)
139 {
140         *index = c->index;
141         return console_driver;
142 }
143 
144 static int uml_console_setup(struct console *co, char *options)
145 {
146         struct line *line = &vts[co->index];
147 
148         return console_open_chan(line, co);
149 }
150 
151 /* No locking for register_console call - relies on single-threaded initcalls */
152 static struct console stdiocons = {
153         .name           = "tty",
154         .write          = uml_console_write,
155         .device         = uml_console_device,
156         .setup          = uml_console_setup,
157         .flags          = CON_PRINTBUFFER|CON_ANYTIME,
158         .index          = -1,
159 };
160 
161 static int stdio_init(void)
162 {
163         char *new_title;
164 
165         console_driver = register_lines(&driver, &console_ops, vts,
166                                         ARRAY_SIZE(vts));
167         if (console_driver == NULL)
168                 return -1;
169         printk(KERN_INFO "Initialized stdio console driver\n");
170 
171         new_title = add_xterm_umid(opts.xterm_title);
172         if(new_title != NULL)
173                 opts.xterm_title = new_title;
174 
175         lines_init(vts, ARRAY_SIZE(vts), &opts);
176 
177         con_init_done = 1;
178         register_console(&stdiocons);
179         return 0;
180 }
181 late_initcall(stdio_init);
182 
183 static 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 
191 static int console_chan_setup(char *str)
192 {
193         char *error;
194         int ret;
195 
196         ret = line_setup(vts, ARRAY_SIZE(vts), str, &error);
197         if(ret < 0)
198                 printk(KERN_ERR "Failed to set up console with "
199                        "configuration string \"%s\" : %s\n", str, error);
200 
201         return 1;
202 }
203 __setup("con", console_chan_setup);
204 __channel_help(console_chan_setup, "con");
205 
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