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