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