drivers/hwtracing/stm/console.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Simple kernel console driver for STM devices
   4  * Copyright (c) 2014, Intel Corporation.
   5  *
   6  * STM console will send kernel messages over STM devices to a trace host.
   7  */
   8
   9 #include <linux/kernel.h>
  10 #include <linux/module.h>
  11 #include <linux/console.h>
  12 #include <linux/slab.h>
  13 #include <linux/stm.h>
  14
  15 static int stm_console_link(struct stm_source_data *data);
  16 static void stm_console_unlink(struct stm_source_data *data);
  17
  18 static struct stm_console {
  19         struct stm_source_data  data;
  20         struct console          console;
  21 } stm_console = {
  22         .data   = {
  23                 .name           = "console",
  24                 .nr_chans       = 1,
  25                 .link           = stm_console_link,
  26                 .unlink         = stm_console_unlink,
  27         },
  28 };
  29
  30 static void
  31 stm_console_write(struct console *con, const char *buf, unsigned len)
  32 {
  33         struct stm_console *sc = container_of(con, struct stm_console, console);
  34
  35         stm_source_write(&sc->data, 0, buf, len);
  36 }
  37
  38 static int stm_console_link(struct stm_source_data *data)
  39 {
  40         struct stm_console *sc = container_of(data, struct stm_console, data);
  41
  42         strcpy(sc->console.name, "stm_console");
  43         sc->console.write = stm_console_write;
  44         sc->console.flags = CON_ENABLED | CON_PRINTBUFFER;
  45         register_console(&sc->console);
  46
  47         return 0;
  48 }
  49
  50 static void stm_console_unlink(struct stm_source_data *data)
  51 {
  52         struct stm_console *sc = container_of(data, struct stm_console, data);
  53
  54         unregister_console(&sc->console);
  55 }
  56
  57 static int stm_console_init(void)
  58 {
  59         return stm_source_register_device(NULL, &stm_console.data);
  60 }
  61
  62 static void stm_console_exit(void)
  63 {
  64         stm_source_unregister_device(&stm_console.data);
  65 }
  66
  67 module_init(stm_console_init);
  68 module_exit(stm_console_exit);
  69
  70 MODULE_LICENSE("GPL v2");
  71 MODULE_DESCRIPTION("stm_console driver");
  72 MODULE_AUTHOR("Alexander Shishkin <alexander.shishkin@linux.intel.com>");