xref: /linux/drivers/hwtracing/stm/p_basic.c (revision 8ab1b51fa45e29edcbd887208f046a2af0e92a08)
1  // SPDX-License-Identifier: GPL-2.0
2  /*
3   * Basic framing protocol for STM devices.
4   * Copyright (c) 2018, Intel Corporation.
5   */
6  
7  #include <linux/module.h>
8  #include <linux/device.h>
9  #include <linux/stm.h>
10  #include "stm.h"
11  
12  static ssize_t basic_write(struct stm_data *data, struct stm_output *output,
13  			   unsigned int chan, const char *buf, size_t count,
14  			   struct stm_source_data *source)
15  {
16  	unsigned int c = output->channel + chan;
17  	unsigned int m = output->master;
18  	const unsigned char nil = 0;
19  	ssize_t sz;
20  
21  	sz = stm_data_write(data, m, c, true, buf, count);
22  	if (sz > 0)
23  		data->packet(data, m, c, STP_PACKET_FLAG, 0, 0, &nil);
24  
25  	return sz;
26  }
27  
28  static const struct stm_protocol_driver basic_pdrv = {
29  	.owner	= THIS_MODULE,
30  	.name	= "p_basic",
31  	.write	= basic_write,
32  };
33  
34  static int basic_stm_init(void)
35  {
36  	return stm_register_protocol(&basic_pdrv);
37  }
38  
39  static void basic_stm_exit(void)
40  {
41  	stm_unregister_protocol(&basic_pdrv);
42  }
43  
44  module_init(basic_stm_init);
45  module_exit(basic_stm_exit);
46  
47  MODULE_LICENSE("GPL v2");
48  MODULE_DESCRIPTION("Basic STM framing protocol driver");
49  MODULE_AUTHOR("Alexander Shishkin <alexander.shishkin@linux.intel.com>");
50