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