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                 .type           = STM_USER,
  26                 .link           = stm_console_link,
  27                 .unlink         = stm_console_unlink,
  28         },
  29 };
  30
  31 static void
  32 stm_console_write(struct console *con, const char *buf, unsigned len)
  33 {
  34         struct stm_console *sc = container_of(con, struct stm_console, console);
  35
  36         stm_source_write(&sc->data, 0, buf, len);
  37 }
  38
  39 static int stm_console_link(struct stm_source_data *data)
  40 {
  41         struct stm_console *sc = container_of(data, struct stm_console, data);
  42
  43         strcpy(sc->console.name, "stm_console");
  44         sc->console.write = stm_console_write;
  45         sc->console.flags = CON_ENABLED | CON_PRINTBUFFER;
  46         register_console(&sc->console);
  47
  48         return 0;
  49 }
  50
  51 static void stm_console_unlink(struct stm_source_data *data)
  52 {
  53         struct stm_console *sc = container_of(data, struct stm_console, data);
  54
  55         unregister_console(&sc->console);
  56 }
  57
  58 static int stm_console_init(void)
  59 {
  60         return stm_source_register_device(NULL, &stm_console.data);
  61 }
  62
  63 static void stm_console_exit(void)
  64 {
  65         stm_source_unregister_device(&stm_console.data);
  66 }
  67
  68 module_init(stm_console_init);
  69 module_exit(stm_console_exit);
  70
  71 MODULE_LICENSE("GPL v2");
  72 MODULE_DESCRIPTION("stm_console driver");
  73 MODULE_AUTHOR("Alexander Shishkin <[email protected]>");