arch/m68k/emu/nfcon.c

   1 /*
   2  * ARAnyM console driver
   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
   9 #include <linux/module.h>
  10 #include <linux/init.h>
  11 #include <linux/console.h>
  12 #include <linux/tty.h>
  13 #include <linux/tty_driver.h>
  14 #include <linux/tty_flip.h>
  15 #include <linux/slab.h>
  16 #include <linux/err.h>
  17 #include <linux/uaccess.h>
  18 #include <linux/io.h>
  19
  20 #include <asm/natfeat.h>
  21
  22 static int stderr_id;
  23 static struct tty_port nfcon_tty_port;
  24 static struct tty_driver *nfcon_tty_driver;
  25
  26 static void nfputs(const u8 *str, size_t count)
  27 {
  28         u8 buf[68];
  29         unsigned long phys = virt_to_phys(buf);
  30
  31         buf[64] = 0;
  32         while (count > 64) {
  33                 memcpy(buf, str, 64);
  34                 nf_call(stderr_id, phys);
  35                 str += 64;
  36                 count -= 64;
  37         }
  38         memcpy(buf, str, count);
  39         buf[count] = 0;
  40         nf_call(stderr_id, phys);
  41 }
  42
  43 static void nfcon_write(struct console *con, const char *str,
  44                         unsigned int count)
  45 {
  46         nfputs(str, count);
  47 }
  48
  49 static struct tty_driver *nfcon_device(struct console *con, int *index)
  50 {
  51         *index = 0;
  52         return console_is_registered(con) ? nfcon_tty_driver : NULL;
  53 }
  54
  55 static struct console nf_console = {
  56         .name   = "nfcon",
  57         .write  = nfcon_write,
  58         .device = nfcon_device,
  59         .flags  = CON_PRINTBUFFER,
  60         .index  = -1,
  61 };
  62
  63
  64 static int nfcon_tty_open(struct tty_struct *tty, struct file *filp)
  65 {
  66         return 0;
  67 }
  68
  69 static void nfcon_tty_close(struct tty_struct *tty, struct file *filp)
  70 {
  71 }
  72
  73 static ssize_t nfcon_tty_write(struct tty_struct *tty, const u8 *buf,
  74                                size_t count)
  75 {
  76         nfputs(buf, count);
  77         return count;
  78 }
  79
  80 static int nfcon_tty_put_char(struct tty_struct *tty, u8 ch)
  81 {
  82         u8 temp[2] = { ch, 0 };
  83
  84         nf_call(stderr_id, virt_to_phys(temp));
  85         return 1;
  86 }
  87
  88 static unsigned int nfcon_tty_write_room(struct tty_struct *tty)
  89 {
  90         return 64;
  91 }
  92
  93 static const struct tty_operations nfcon_tty_ops = {
  94         .open           = nfcon_tty_open,
  95         .close          = nfcon_tty_close,
  96         .write          = nfcon_tty_write,
  97         .put_char       = nfcon_tty_put_char,
  98         .write_room     = nfcon_tty_write_room,
  99 };
 100
 101 #ifndef MODULE
 102
 103 static int __init nf_debug_setup(char *arg)
 104 {
 105         if (strcmp(arg, "nfcon"))
 106                 return 0;
 107
 108         stderr_id = nf_get_id("NF_STDERR");
 109         if (stderr_id) {
 110                 /*
 111                  * The console will be enabled when debug=nfcon is specified
 112                  * as a kernel parameter. Since this is a non-standard way
 113                  * of enabling consoles, it must be explicitly enabled.
 114                  */
 115                 nf_console.flags |= CON_ENABLED;
 116                 register_console(&nf_console);
 117         }
 118
 119         return 0;
 120 }
 121
 122 early_param("debug", nf_debug_setup);
 123
 124 #endif /* !MODULE */
 125
 126 static int __init nfcon_init(void)
 127 {
 128         struct tty_driver *driver;
 129         int res;
 130
 131         stderr_id = nf_get_id("NF_STDERR");
 132         if (!stderr_id)
 133                 return -ENODEV;
 134
 135         driver = tty_alloc_driver(1, TTY_DRIVER_REAL_RAW);
 136         if (IS_ERR(driver))
 137                 return PTR_ERR(driver);
 138
 139         tty_port_init(&nfcon_tty_port);
 140
 141         driver->driver_name = "nfcon";
 142         driver->name = "nfcon";
 143         driver->type = TTY_DRIVER_TYPE_SYSTEM;
 144         driver->subtype = SYSTEM_TYPE_TTY;
 145         driver->init_termios = tty_std_termios;
 146
 147         tty_set_operations(driver, &nfcon_tty_ops);
 148         tty_port_link_device(&nfcon_tty_port, driver, 0);
 149         res = tty_register_driver(driver);
 150         if (res) {
 151                 pr_err("failed to register nfcon tty driver\n");
 152                 tty_driver_kref_put(driver);
 153                 tty_port_destroy(&nfcon_tty_port);
 154                 return res;
 155         }
 156
 157         nfcon_tty_driver = driver;
 158
 159         if (!console_is_registered(&nf_console))
 160                 register_console(&nf_console);
 161
 162         return 0;
 163 }
 164
 165 static void __exit nfcon_exit(void)
 166 {
 167         unregister_console(&nf_console);
 168         tty_unregister_driver(nfcon_tty_driver);
 169         tty_driver_kref_put(nfcon_tty_driver);
 170         tty_port_destroy(&nfcon_tty_port);
 171 }
 172
 173 module_init(nfcon_init);
 174 module_exit(nfcon_exit);
 175
 176 MODULE_DESCRIPTION("Atari NatFeat console driver");
 177 MODULE_LICENSE("GPL");