drivers/hwtracing/stm/dummy_stm.c

   1 /*
   2  * A dummy STM device for stm/stm_source class testing.
   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 class implements generic infrastructure for  System Trace Module devices
  15  * as defined in MIPI STPv2 specification.
  16  */
  17
  18 #undef DEBUG
  19 #include <linux/kernel.h>
  20 #include <linux/module.h>
  21 #include <linux/slab.h>
  22 #include <linux/stm.h>
  23
  24 static ssize_t
  25 dummy_stm_packet(struct stm_data *stm_data, unsigned int master,
  26                  unsigned int channel, unsigned int packet, unsigned int flags,
  27                  unsigned int size, const unsigned char *payload)
  28 {
  29 #ifdef DEBUG
  30         u64 pl = 0;
  31
  32         if (payload)
  33                 pl = *(u64 *)payload;
  34
  35         if (size < 8)
  36                 pl &= (1ull << (size * 8)) - 1;
  37         trace_printk("[%u:%u] [pkt: %x/%x] (%llx)\n", master, channel,
  38                      packet, size, pl);
  39 #endif
  40         return size;
  41 }
  42
  43 static struct stm_data dummy_stm = {
  44         .name           = "dummy_stm",
  45         .sw_start       = 0x0000,
  46         .sw_end         = 0xffff,
  47         .sw_nchannels   = 0xffff,
  48         .packet         = dummy_stm_packet,
  49 };
  50
  51 static int dummy_stm_init(void)
  52 {
  53         return stm_register_device(NULL, &dummy_stm, THIS_MODULE);
  54 }
  55
  56 static void dummy_stm_exit(void)
  57 {
  58         stm_unregister_device(&dummy_stm);
  59 }
  60
  61 module_init(dummy_stm_init);
  62 module_exit(dummy_stm_exit);
  63
  64 MODULE_LICENSE("GPL v2");
  65 MODULE_DESCRIPTION("dummy_stm device");
  66 MODULE_AUTHOR("Alexander Shishkin <alexander.shishkin@linux.intel.com>");