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 #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         unsigned char c;
 100
 101         spin_lock(&timer_lock);
 102
 103         while (simc_poll(0)) {
 104                 simc_read(0, &c, 1);
 105                 tty_insert_flip_char(port, c, TTY_NORMAL);
 106                 i++;
 107         }
 108
 109         if (i)
 110                 tty_flip_buffer_push(port);
 111
 112
 113         mod_timer(&serial_timer, jiffies + SERIAL_TIMER_VALUE);
 114         spin_unlock(&timer_lock);
 115 }
 116
 117
 118 static int rs_put_char(struct tty_struct *tty, unsigned char ch)
 119 {
 120         return rs_write(tty, &ch, 1);
 121 }
 122
 123 static void rs_flush_chars(struct tty_struct *tty)
 124 {
 125 }
 126
 127 static int rs_write_room(struct tty_struct *tty)
 128 {
 129         /* Let's say iss can always accept 2K characters.. */
 130         return 2 * 1024;
 131 }
 132
 133 static int rs_chars_in_buffer(struct tty_struct *tty)
 134 {
 135         /* the iss doesn't buffer characters */
 136         return 0;
 137 }
 138
 139 static void rs_hangup(struct tty_struct *tty)
 140 {
 141         /* Stub, once again.. */
 142 }
 143
 144 static void rs_wait_until_sent(struct tty_struct *tty, int timeout)
 145 {
 146         /* Stub, once again.. */
 147 }
 148
 149 static int rs_proc_show(struct seq_file *m, void *v)
 150 {
 151         seq_printf(m, "serinfo:1.0 driver:%s\n", serial_version);
 152         return 0;
 153 }
 154
 155 static int rs_proc_open(struct inode *inode, struct file *file)
 156 {
 157         return single_open(file, rs_proc_show, NULL);
 158 }
 159
 160 static const struct file_operations rs_proc_fops = {
 161         .owner          = THIS_MODULE,
 162         .open           = rs_proc_open,
 163         .read           = seq_read,
 164         .llseek         = seq_lseek,
 165         .release        = single_release,
 166 };
 167
 168 static const struct tty_operations serial_ops = {
 169         .open = rs_open,
 170         .close = rs_close,
 171         .write = rs_write,
 172         .put_char = rs_put_char,
 173         .flush_chars = rs_flush_chars,
 174         .write_room = rs_write_room,
 175         .chars_in_buffer = rs_chars_in_buffer,
 176         .hangup = rs_hangup,
 177         .wait_until_sent = rs_wait_until_sent,
 178         .proc_fops = &rs_proc_fops,
 179 };
 180
 181 int __init rs_init(void)
 182 {
 183         tty_port_init(&serial_port);
 184
 185         serial_driver = alloc_tty_driver(SERIAL_MAX_NUM_LINES);
 186
 187         printk ("%s %s\n", serial_name, serial_version);
 188
 189         /* Initialize the tty_driver structure */
 190
 191         serial_driver->driver_name = "iss_serial";
 192         serial_driver->name = "ttyS";
 193         serial_driver->major = TTY_MAJOR;
 194         serial_driver->minor_start = 64;
 195         serial_driver->type = TTY_DRIVER_TYPE_SERIAL;
 196         serial_driver->subtype = SERIAL_TYPE_NORMAL;
 197         serial_driver->init_termios = tty_std_termios;
 198         serial_driver->init_termios.c_cflag =
 199                 B9600 | CS8 | CREAD | HUPCL | CLOCAL;
 200         serial_driver->flags = TTY_DRIVER_REAL_RAW;
 201
 202         tty_set_operations(serial_driver, &serial_ops);
 203         tty_port_link_device(&serial_port, serial_driver, 0);
 204
 205         if (tty_register_driver(serial_driver))
 206                 panic("Couldn't register serial driver\n");
 207         return 0;
 208 }
 209
 210
 211 static __exit void rs_exit(void)
 212 {
 213         int error;
 214
 215         if ((error = tty_unregister_driver(serial_driver)))
 216                 printk("ISS_SERIAL: failed to unregister serial driver (%d)\n",
 217                        error);
 218         put_tty_driver(serial_driver);
 219         tty_port_destroy(&serial_port);
 220 }
 221
 222
 223 /* We use `late_initcall' instead of just `__initcall' as a workaround for
 224  * the fact that (1) simcons_tty_init can't be called before tty_init,
 225  * (2) tty_init is called via `module_init', (3) if statically linked,
 226  * module_init == device_init, and (4) there's no ordering of init lists.
 227  * We can do this easily because simcons is always statically linked, but
 228  * other tty drivers that depend on tty_init and which must use
 229  * `module_init' to declare their init routines are likely to be broken.
 230  */
 231
 232 late_initcall(rs_init);
 233
 234
 235 #ifdef CONFIG_SERIAL_CONSOLE
 236
 237 static void iss_console_write(struct console *co, const char *s, unsigned count)
 238 {
 239         int len = strlen(s);
 240
 241         if (s != 0 && *s != 0)
 242                 simc_write(1, s, count < len ? count : len);
 243 }
 244
 245 static struct tty_driver* iss_console_device(struct console *c, int *index)
 246 {
 247         *index = c->index;
 248         return serial_driver;
 249 }
 250
 251
 252 static struct console sercons = {
 253         .name = "ttyS",
 254         .write = iss_console_write,
 255         .device = iss_console_device,
 256         .flags = CON_PRINTBUFFER,
 257         .index = -1
 258 };
 259
 260 static int __init iss_console_init(void)
 261 {
 262         register_console(&sercons);
 263         return 0;
 264 }
 265
 266 console_initcall(iss_console_init);
 267
 268 #endif /* CONFIG_SERIAL_CONSOLE */
 269