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