arch/xtensa/platforms/iss/console.c

   1 /*
   2  * arch/xtensa/platforms/iss/console.c
   3  *
   4  * This file is subject to the terms and conditions of the GNU General Public
   5  * License.  See the file "COPYING" in the main directory of this archive
   6  * for more details.
   7  *
   8  * Copyright (C) 2001-2005 Tensilica Inc.
   9  *   Authors    Christian Zankel, Joe Taylor
  10  */
  11
  12 #include <linux/module.h>
  13 #include <linux/kernel.h>
  14 #include <linux/sched.h>
  15 #include <linux/console.h>
  16 #include <linux/init.h>
  17 #include <linux/mm.h>
  18 #include <linux/major.h>
  19 #include <linux/param.h>
  20 #include <linux/seq_file.h>
  21 #include <linux/serial.h>
  22
  23 #include <linux/uaccess.h>
  24 #include <asm/irq.h>
  25
  26 #include <platform/simcall.h>
  27
  28 #include <linux/tty.h>
  29 #include <linux/tty_flip.h>
  30
  31 #define SERIAL_MAX_NUM_LINES 1
  32 #define SERIAL_TIMER_VALUE (HZ / 10)
  33
  34 static void rs_poll(struct timer_list *);
  35
  36 static struct tty_driver *serial_driver;
  37 static struct tty_port serial_port;
  38 static DEFINE_TIMER(serial_timer, rs_poll);
  39
  40 static int rs_open(struct tty_struct *tty, struct file * filp)
  41 {
  42         if (tty->count == 1)
  43                 mod_timer(&serial_timer, jiffies + SERIAL_TIMER_VALUE);
  44
  45         return 0;
  46 }
  47
  48 static void rs_close(struct tty_struct *tty, struct file * filp)
  49 {
  50         if (tty->count == 1)
  51                 del_timer_sync(&serial_timer);
  52 }
  53
  54
  55 static ssize_t rs_write(struct tty_struct * tty, const u8 *buf, size_t count)
  56 {
  57         /* see drivers/char/serialX.c to reference original version */
  58
  59         simc_write(1, buf, count);
  60         return count;
  61 }
  62
  63 static void rs_poll(struct timer_list *unused)
  64 {
  65         struct tty_port *port = &serial_port;
  66         int i = 0;
  67         int rd = 1;
  68         u8 c;
  69
  70         while (simc_poll(0)) {
  71                 rd = simc_read(0, &c, 1);
  72                 if (rd <= 0)
  73                         break;
  74                 tty_insert_flip_char(port, c, TTY_NORMAL);
  75                 i++;
  76         }
  77
  78         if (i)
  79                 tty_flip_buffer_push(port);
  80         if (rd)
  81                 mod_timer(&serial_timer, jiffies + SERIAL_TIMER_VALUE);
  82 }
  83
  84 static unsigned int rs_write_room(struct tty_struct *tty)
  85 {
  86         /* Let's say iss can always accept 2K characters.. */
  87         return 2 * 1024;
  88 }
  89
  90 static int rs_proc_show(struct seq_file *m, void *v)
  91 {
  92         seq_printf(m, "serinfo:1.0 driver:0.1\n");
  93         return 0;
  94 }
  95
  96 static const struct tty_operations serial_ops = {
  97         .open = rs_open,
  98         .close = rs_close,
  99         .write = rs_write,
 100         .write_room = rs_write_room,
 101         .proc_show = rs_proc_show,
 102 };
 103
 104 static int __init rs_init(void)
 105 {
 106         struct tty_driver *driver;
 107         int ret;
 108
 109         driver = tty_alloc_driver(SERIAL_MAX_NUM_LINES, TTY_DRIVER_REAL_RAW);
 110         if (IS_ERR(driver))
 111                 return PTR_ERR(driver);
 112
 113         tty_port_init(&serial_port);
 114
 115         /* Initialize the tty_driver structure */
 116
 117         driver->driver_name = "iss_serial";
 118         driver->name = "ttyS";
 119         driver->major = TTY_MAJOR;
 120         driver->minor_start = 64;
 121         driver->type = TTY_DRIVER_TYPE_SERIAL;
 122         driver->subtype = SERIAL_TYPE_NORMAL;
 123         driver->init_termios = tty_std_termios;
 124         driver->init_termios.c_cflag =
 125                 B9600 | CS8 | CREAD | HUPCL | CLOCAL;
 126
 127         tty_set_operations(driver, &serial_ops);
 128         tty_port_link_device(&serial_port, driver, 0);
 129
 130         ret = tty_register_driver(driver);
 131         if (ret) {
 132                 pr_err("Couldn't register serial driver\n");
 133                 tty_driver_kref_put(driver);
 134                 tty_port_destroy(&serial_port);
 135
 136                 return ret;
 137         }
 138
 139         serial_driver = driver;
 140
 141         return 0;
 142 }
 143
 144
 145 static __exit void rs_exit(void)
 146 {
 147         tty_unregister_driver(serial_driver);
 148         tty_driver_kref_put(serial_driver);
 149         tty_port_destroy(&serial_port);
 150 }
 151
 152
 153 /* We use `late_initcall' instead of just `__initcall' as a workaround for
 154  * the fact that (1) simcons_tty_init can't be called before tty_init,
 155  * (2) tty_init is called via `module_init', (3) if statically linked,
 156  * module_init == device_init, and (4) there's no ordering of init lists.
 157  * We can do this easily because simcons is always statically linked, but
 158  * other tty drivers that depend on tty_init and which must use
 159  * `module_init' to declare their init routines are likely to be broken.
 160  */
 161
 162 late_initcall(rs_init);
 163
 164
 165 #ifdef CONFIG_SERIAL_CONSOLE
 166
 167 static void iss_console_write(struct console *co, const char *s, unsigned count)
 168 {
 169         if (s && *s != 0)
 170                 simc_write(1, s, min(count, strlen(s)));
 171 }
 172
 173 static struct tty_driver* iss_console_device(struct console *c, int *index)
 174 {
 175         *index = c->index;
 176         return serial_driver;
 177 }
 178
 179
 180 static struct console sercons = {
 181         .name = "ttyS",
 182         .write = iss_console_write,
 183         .device = iss_console_device,
 184         .flags = CON_PRINTBUFFER,
 185         .index = -1
 186 };
 187
 188 static int __init iss_console_init(void)
 189 {
 190         register_console(&sercons);
 191         return 0;
 192 }
 193
 194 console_initcall(iss_console_init);
 195
 196 #endif /* CONFIG_SERIAL_CONSOLE */
 197