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