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 <linux/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 #define SERIAL_MAX_NUM_LINES 1
  32 #define SERIAL_TIMER_VALUE (HZ / 10)
  33
  34 static struct tty_driver *serial_driver;
  35 static struct tty_port serial_port;
  36 static struct timer_list serial_timer;
  37
  38 static DEFINE_SPINLOCK(timer_lock);
  39
  40 static char *serial_version = "0.1";
  41 static char *serial_name = "ISS serial driver";
  42
  43 /*
  44  * This routine is called whenever a serial port is opened.  It
  45  * enables interrupts for a serial port, linking in its async structure into
  46  * the IRQ chain.   It also performs the serial-specific
  47  * initialization for the tty structure.
  48  */
  49
  50 static void rs_poll(unsigned long);
  51
  52 static int rs_open(struct tty_struct *tty, struct file * filp)
  53 {
  54         tty->port = &serial_port;
  55         spin_lock_bh(&timer_lock);
  56         if (tty->count == 1) {
  57                 setup_timer(&serial_timer, rs_poll,
  58                                 (unsigned long)&serial_port);
  59                 mod_timer(&serial_timer, jiffies + SERIAL_TIMER_VALUE);
  60         }
  61         spin_unlock_bh(&timer_lock);
  62
  63         return 0;
  64 }
  65
  66
  67 /*
  68  * ------------------------------------------------------------
  69  * iss_serial_close()
  70  *
  71  * This routine is called when the serial port gets closed.  First, we
  72  * wait for the last remaining data to be sent.  Then, we unlink its
  73  * async structure from the interrupt chain if necessary, and we free
  74  * that IRQ if nothing is left in the chain.
  75  * ------------------------------------------------------------
  76  */
  77 static void rs_close(struct tty_struct *tty, struct file * filp)
  78 {
  79         spin_lock_bh(&timer_lock);
  80         if (tty->count == 1)
  81                 del_timer_sync(&serial_timer);
  82         spin_unlock_bh(&timer_lock);
  83 }
  84
  85
  86 static int rs_write(struct tty_struct * tty,
  87                     const unsigned char *buf, int count)
  88 {
  89         /* see drivers/char/serialX.c to reference original version */
  90
  91         simc_write(1, buf, count);
  92         return count;
  93 }
  94
  95 static void rs_poll(unsigned long priv)
  96 {
  97         struct tty_port *port = (struct tty_port *)priv;
  98         int i = 0;
  99         int rd = 1;
 100         unsigned char c;
 101
 102         spin_lock(&timer_lock);
 103
 104         while (simc_poll(0)) {
 105                 rd = simc_read(0, &c, 1);
 106                 if (rd <= 0)
 107                         break;
 108                 tty_insert_flip_char(port, c, TTY_NORMAL);
 109                 i++;
 110         }
 111
 112         if (i)
 113                 tty_flip_buffer_push(port);
 114         if (rd)
 115                 mod_timer(&serial_timer, jiffies + SERIAL_TIMER_VALUE);
 116         spin_unlock(&timer_lock);
 117 }
 118
 119
 120 static int rs_put_char(struct tty_struct *tty, unsigned char ch)
 121 {
 122         return rs_write(tty, &ch, 1);
 123 }
 124
 125 static void rs_flush_chars(struct tty_struct *tty)
 126 {
 127 }
 128
 129 static int rs_write_room(struct tty_struct *tty)
 130 {
 131         /* Let's say iss can always accept 2K characters.. */
 132         return 2 * 1024;
 133 }
 134
 135 static int rs_chars_in_buffer(struct tty_struct *tty)
 136 {
 137         /* the iss doesn't buffer characters */
 138         return 0;
 139 }
 140
 141 static void rs_hangup(struct tty_struct *tty)
 142 {
 143         /* Stub, once again.. */
 144 }
 145
 146 static void rs_wait_until_sent(struct tty_struct *tty, int timeout)
 147 {
 148         /* Stub, once again.. */
 149 }
 150
 151 static int rs_proc_show(struct seq_file *m, void *v)
 152 {
 153         seq_printf(m, "serinfo:1.0 driver:%s\n", serial_version);
 154         return 0;
 155 }
 156
 157 static int rs_proc_open(struct inode *inode, struct file *file)
 158 {
 159         return single_open(file, rs_proc_show, NULL);
 160 }
 161
 162 static const struct file_operations rs_proc_fops = {
 163         .owner          = THIS_MODULE,
 164         .open           = rs_proc_open,
 165         .read           = seq_read,
 166         .llseek         = seq_lseek,
 167         .release        = single_release,
 168 };
 169
 170 static const struct tty_operations serial_ops = {
 171         .open = rs_open,
 172         .close = rs_close,
 173         .write = rs_write,
 174         .put_char = rs_put_char,
 175         .flush_chars = rs_flush_chars,
 176         .write_room = rs_write_room,
 177         .chars_in_buffer = rs_chars_in_buffer,
 178         .hangup = rs_hangup,
 179         .wait_until_sent = rs_wait_until_sent,
 180         .proc_fops = &rs_proc_fops,
 181 };
 182
 183 int __init rs_init(void)
 184 {
 185         tty_port_init(&serial_port);
 186
 187         serial_driver = alloc_tty_driver(SERIAL_MAX_NUM_LINES);
 188
 189         printk ("%s %s\n", serial_name, serial_version);
 190
 191         /* Initialize the tty_driver structure */
 192
 193         serial_driver->driver_name = "iss_serial";
 194         serial_driver->name = "ttyS";
 195         serial_driver->major = TTY_MAJOR;
 196         serial_driver->minor_start = 64;
 197         serial_driver->type = TTY_DRIVER_TYPE_SERIAL;
 198         serial_driver->subtype = SERIAL_TYPE_NORMAL;
 199         serial_driver->init_termios = tty_std_termios;
 200         serial_driver->init_termios.c_cflag =
 201                 B9600 | CS8 | CREAD | HUPCL | CLOCAL;
 202         serial_driver->flags = TTY_DRIVER_REAL_RAW;
 203
 204         tty_set_operations(serial_driver, &serial_ops);
 205         tty_port_link_device(&serial_port, serial_driver, 0);
 206
 207         if (tty_register_driver(serial_driver))
 208                 panic("Couldn't register serial driver\n");
 209         return 0;
 210 }
 211
 212
 213 static __exit void rs_exit(void)
 214 {
 215         int error;
 216
 217         if ((error = tty_unregister_driver(serial_driver)))
 218                 printk("ISS_SERIAL: failed to unregister serial driver (%d)\n",
 219                        error);
 220         put_tty_driver(serial_driver);
 221         tty_port_destroy(&serial_port);
 222 }
 223
 224
 225 /* We use `late_initcall' instead of just `__initcall' as a workaround for
 226  * the fact that (1) simcons_tty_init can't be called before tty_init,
 227  * (2) tty_init is called via `module_init', (3) if statically linked,
 228  * module_init == device_init, and (4) there's no ordering of init lists.
 229  * We can do this easily because simcons is always statically linked, but
 230  * other tty drivers that depend on tty_init and which must use
 231  * `module_init' to declare their init routines are likely to be broken.
 232  */
 233
 234 late_initcall(rs_init);
 235
 236
 237 #ifdef CONFIG_SERIAL_CONSOLE
 238
 239 static void iss_console_write(struct console *co, const char *s, unsigned count)
 240 {
 241         int len = strlen(s);
 242
 243         if (s != 0 && *s != 0)
 244                 simc_write(1, s, count < len ? count : len);
 245 }
 246
 247 static struct tty_driver* iss_console_device(struct console *c, int *index)
 248 {
 249         *index = c->index;
 250         return serial_driver;
 251 }
 252
 253
 254 static struct console sercons = {
 255         .name = "ttyS",
 256         .write = iss_console_write,
 257         .device = iss_console_device,
 258         .flags = CON_PRINTBUFFER,
 259         .index = -1
 260 };
 261
 262 static int __init iss_console_init(void)
 263 {
 264         register_console(&sercons);
 265         return 0;
 266 }
 267
 268 console_initcall(iss_console_init);
 269
 270 #endif /* CONFIG_SERIAL_CONSOLE */
 271