drivers/hwtracing/stm/console.c

   1 /*
   2  * Simple kernel console driver for STM devices
   3  * Copyright (c) 2014, Intel Corporation.
   4  *
   5  * This program is free software; you can redistribute it and/or modify it
   6  * under the terms and conditions of the GNU General Public License,
   7  * version 2, as published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  12  * more details.
  13  *
  14  * STM console will send kernel messages over STM devices to a trace host.
  15  */
  16
  17 #include <linux/kernel.h>
  18 #include <linux/module.h>
  19 #include <linux/console.h>
  20 #include <linux/slab.h>
  21 #include <linux/stm.h>
  22
  23 static int stm_console_link(struct stm_source_data *data);
  24 static void stm_console_unlink(struct stm_source_data *data);
  25
  26 static struct stm_console {
  27         struct stm_source_data  data;
  28         struct console          console;
  29 } stm_console = {
  30         .data   = {
  31                 .name           = "console",
  32                 .nr_chans       = 1,
  33                 .link           = stm_console_link,
  34                 .unlink         = stm_console_unlink,
  35         },
  36 };
  37
  38 static void
  39 stm_console_write(struct console *con, const char *buf, unsigned len)
  40 {
  41         struct stm_console *sc = container_of(con, struct stm_console, console);
  42
  43         stm_source_write(&sc->data, 0, buf, len);
  44 }
  45
  46 static int stm_console_link(struct stm_source_data *data)
  47 {
  48         struct stm_console *sc = container_of(data, struct stm_console, data);
  49
  50         strcpy(sc->console.name, "stm_console");
  51         sc->console.write = stm_console_write;
  52         sc->console.flags = CON_ENABLED | CON_PRINTBUFFER;
  53         register_console(&sc->console);
  54
  55         return 0;
  56 }
  57
  58 static void stm_console_unlink(struct stm_source_data *data)
  59 {
  60         struct stm_console *sc = container_of(data, struct stm_console, data);
  61
  62         unregister_console(&sc->console);
  63 }
  64
  65 static int stm_console_init(void)
  66 {
  67         return stm_source_register_device(NULL, &stm_console.data);
  68 }
  69
  70 static void stm_console_exit(void)
  71 {
  72         stm_source_unregister_device(&stm_console.data);
  73 }
  74
  75 module_init(stm_console_init);
  76 module_exit(stm_console_exit);
  77
  78 MODULE_LICENSE("GPL v2");
  79 MODULE_DESCRIPTION("stm_console driver");
  80 MODULE_AUTHOR("Alexander Shishkin <alexander.shishkin@linux.intel.com>");