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