arch/xtensa/platform-iss/console.c

   1 /*
   2  * arch/xtensa/platform-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/config.h>
  14 #include <linux/kernel.h>
  15 #include <linux/sched.h>
  16 #include <linux/console.h>
  17 #include <linux/init.h>
  18 #include <linux/slab.h>
  19 #include <linux/mm.h>
  20 #include <linux/major.h>
  21 #include <linux/param.h>
  22 #include <linux/serial.h>
  23 #include <linux/serialP.h>
  24 #include <linux/console.h>
  25
  26 #include <asm/uaccess.h>
  27 #include <asm/irq.h>
  28
  29 #include <xtensa/simcall.h>
  30
  31 #include <linux/tty.h>
  32 #include <linux/tty_flip.h>
  33
  34 #ifdef SERIAL_INLINE
  35 #define _INLINE_ inline
  36 #endif
  37
  38 #define SERIAL_MAX_NUM_LINES 1
  39 #define SERIAL_TIMER_VALUE (20 * HZ)
  40
  41 static struct tty_driver *serial_driver;
  42 static struct timer_list serial_timer;
  43
  44 static DEFINE_SPINLOCK(timer_lock);
  45
  46 int errno;
  47
  48 static int __simc (int a, int b, int c, int d, int e, int f)
  49 {
  50         int ret;
  51         __asm__ __volatile__ ("simcall\n"
  52                         "mov %0, a2\n"
  53                         "mov %1, a3\n" : "=a" (ret), "=a" (errno)
  54                         : : "a2", "a3");
  55         return ret;
  56 }
  57
  58 static char *serial_version = "0.1";
  59 static char *serial_name = "ISS serial driver";
  60
  61 /*
  62  * This routine is called whenever a serial port is opened.  It
  63  * enables interrupts for a serial port, linking in its async structure into
  64  * the IRQ chain.   It also performs the serial-specific
  65  * initialization for the tty structure.
  66  */
  67
  68 static void rs_poll(unsigned long);
  69
  70 static int rs_open(struct tty_struct *tty, struct file * filp)
  71 {
  72         int line = tty->index;
  73
  74         if ((line < 0) || (line >= SERIAL_MAX_NUM_LINES))
  75                 return -ENODEV;
  76
  77         spin_lock(&timer_lock);
  78
  79         if (tty->count == 1) {
  80                 init_timer(&serial_timer);
  81                 serial_timer.data = (unsigned long) tty;
  82                 serial_timer.function = rs_poll;
  83                 mod_timer(&serial_timer, jiffies + SERIAL_TIMER_VALUE);
  84         }
  85         spin_unlock(&timer_lock);
  86
  87         return 0;
  88 }
  89
  90
  91 /*
  92  * ------------------------------------------------------------
  93  * iss_serial_close()
  94  *
  95  * This routine is called when the serial port gets closed.  First, we
  96  * wait for the last remaining data to be sent.  Then, we unlink its
  97  * async structure from the interrupt chain if necessary, and we free
  98  * that IRQ if nothing is left in the chain.
  99  * ------------------------------------------------------------
 100  */
 101 static void rs_close(struct tty_struct *tty, struct file * filp)
 102 {
 103         spin_lock(&timer_lock);
 104         if (tty->count == 1)
 105                 del_timer_sync(&serial_timer);
 106         spin_unlock(&timer_lock);
 107 }
 108
 109
 110 static int rs_write(struct tty_struct * tty,
 111                     const unsigned char *buf, int count)
 112 {
 113         /* see drivers/char/serialX.c to reference original version */
 114
 115         __simc (SYS_write, 1, (unsigned long)buf, count, 0, 0);
 116         return count;
 117 }
 118
 119 static void rs_poll(unsigned long priv)
 120 {
 121         struct tty_struct* tty = (struct tty_struct*) priv;
 122
 123         struct timeval tv = { .tv_sec = 0, .tv_usec = 0 };
 124         int i = 0;
 125         unsigned char c;
 126
 127         spin_lock(&timer_lock);
 128
 129         while (__simc(SYS_select_one, 0, XTISS_SELECT_ONE_READ, (int)&tv,0,0)){
 130                 __simc (SYS_read, 0, (unsigned long)&c, 1, 0, 0);
 131                 tty_insert_flip_char(tty, c, TTY_NORMAL);
 132                 i++;
 133         }
 134
 135         if (i)
 136                 tty_flip_buffer_push(tty);
 137
 138
 139         mod_timer(&serial_timer, jiffies + SERIAL_TIMER_VALUE);
 140         spin_unlock(&timer_lock);
 141 }
 142
 143
 144 static void rs_put_char(struct tty_struct *tty, unsigned char ch)
 145 {
 146         char buf[2];
 147
 148         if (!tty)
 149                 return;
 150
 151         buf[0] = ch;
 152         buf[1] = '\0';          /* Is this NULL necessary? */
 153         __simc (SYS_write, 1, (unsigned long) buf, 1, 0, 0);
 154 }
 155
 156 static void rs_flush_chars(struct tty_struct *tty)
 157 {
 158 }
 159
 160 static int rs_write_room(struct tty_struct *tty)
 161 {
 162         /* Let's say iss can always accept 2K characters.. */
 163         return 2 * 1024;
 164 }
 165
 166 static int rs_chars_in_buffer(struct tty_struct *tty)
 167 {
 168         /* the iss doesn't buffer characters */
 169         return 0;
 170 }
 171
 172 static void rs_hangup(struct tty_struct *tty)
 173 {
 174         /* Stub, once again.. */
 175 }
 176
 177 static void rs_wait_until_sent(struct tty_struct *tty, int timeout)
 178 {
 179         /* Stub, once again.. */
 180 }
 181
 182 static int rs_read_proc(char *page, char **start, off_t off, int count,
 183                         int *eof, void *data)
 184 {
 185         int len = 0;
 186         off_t begin = 0;
 187
 188         len += sprintf(page, "serinfo:1.0 driver:%s\n", serial_version);
 189         *eof = 1;
 190
 191         if (off >= len + begin)
 192                 return 0;
 193
 194         *start = page + (off - begin);
 195         return ((count < begin + len - off) ? count : begin + len - off);
 196 }
 197
 198
 199 static struct tty_operations serial_ops = {
 200         .open = rs_open,
 201         .close = rs_close,
 202         .write = rs_write,
 203         .put_char = rs_put_char,
 204         .flush_chars = rs_flush_chars,
 205         .write_room = rs_write_room,
 206         .chars_in_buffer = rs_chars_in_buffer,
 207         .hangup = rs_hangup,
 208         .wait_until_sent = rs_wait_until_sent,
 209         .read_proc = rs_read_proc
 210 };
 211
 212 int __init rs_init(void)
 213 {
 214         serial_driver = alloc_tty_driver(1);
 215
 216         printk ("%s %s\n", serial_name, serial_version);
 217
 218         /* Initialize the tty_driver structure */
 219
 220         serial_driver->owner = THIS_MODULE;
 221         serial_driver->driver_name = "iss_serial";
 222         serial_driver->name = "ttyS";
 223         serial_driver->major = TTY_MAJOR;
 224         serial_driver->minor_start = 64;
 225         serial_driver->type = TTY_DRIVER_TYPE_SERIAL;
 226         serial_driver->subtype = SERIAL_TYPE_NORMAL;
 227         serial_driver->init_termios = tty_std_termios;
 228         serial_driver->init_termios.c_cflag =
 229                 B9600 | CS8 | CREAD | HUPCL | CLOCAL;
 230         serial_driver->flags = TTY_DRIVER_REAL_RAW;
 231
 232         tty_set_operations(serial_driver, &serial_ops);
 233
 234         if (tty_register_driver(serial_driver))
 235                 panic("Couldn't register serial driver\n");
 236         return 0;
 237 }
 238
 239
 240 static __exit void rs_exit(void)
 241 {
 242         int error;
 243
 244         if ((error = tty_unregister_driver(serial_driver)))
 245                 printk("ISS_SERIAL: failed to unregister serial driver (%d)\n",
 246                        error);
 247         put_tty_driver(serial_driver);
 248 }
 249
 250
 251 /* We use `late_initcall' instead of just `__initcall' as a workaround for
 252  * the fact that (1) simcons_tty_init can't be called before tty_init,
 253  * (2) tty_init is called via `module_init', (3) if statically linked,
 254  * module_init == device_init, and (4) there's no ordering of init lists.
 255  * We can do this easily because simcons is always statically linked, but
 256  * other tty drivers that depend on tty_init and which must use
 257  * `module_init' to declare their init routines are likely to be broken.
 258  */
 259
 260 late_initcall(rs_init);
 261
 262
 263 #ifdef CONFIG_SERIAL_CONSOLE
 264
 265 static void iss_console_write(struct console *co, const char *s, unsigned count)
 266 {
 267         int len = strlen(s);
 268
 269         if (s != 0 && *s != 0)
 270                 __simc (SYS_write, 1, (unsigned long)s,
 271                         count < len ? count : len,0,0);
 272 }
 273
 274 static struct tty_driver* iss_console_device(struct console *c, int *index)
 275 {
 276         *index = c->index;
 277         return serial_driver;
 278 }
 279
 280
 281 static struct console sercons = {
 282         .name = "ttyS",
 283         .write = iss_console_write,
 284         .device = iss_console_device,
 285         .flags = CON_PRINTBUFFER,
 286         .index = -1
 287 };
 288
 289 static int __init iss_console_init(void)
 290 {
 291         register_console(&sercons);
 292         return 0;
 293 }
 294
 295 console_initcall(iss_console_init);
 296
 297 #endif /* CONFIG_SERIAL_CONSOLE */
 298