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
 24static ssize_t
 25dummy_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#define DUMMY_STM_MAX 32
 44
 45static struct stm_data dummy_stm[DUMMY_STM_MAX];
 46
 47static int nr_dummies = 4;
 48
 49module_param(nr_dummies, int, 0600);
 50
 51static unsigned int dummy_stm_nr;
 52
 53static unsigned int fail_mode;
 54
 55module_param(fail_mode, int, 0600);
 56
 57static int dummy_stm_link(struct stm_data *data, unsigned int master,
 58			  unsigned int channel)
 59{
 60	if (fail_mode && (channel & fail_mode))
 61		return -EINVAL;
 62
 63	return 0;
 64}
 65
 66static int dummy_stm_init(void)
 67{
 68	int i, ret = -ENOMEM, __nr_dummies = ACCESS_ONCE(nr_dummies);
 69
 70	if (__nr_dummies < 0 || __nr_dummies > DUMMY_STM_MAX)
 71		return -EINVAL;
 72
 73	for (i = 0; i < __nr_dummies; i++) {
 74		dummy_stm[i].name = kasprintf(GFP_KERNEL, "dummy_stm.%d", i);
 75		if (!dummy_stm[i].name)
 76			goto fail_unregister;
 77
 78		dummy_stm[i].sw_start		= 0x0000;
 79		dummy_stm[i].sw_end		= 0xffff;
 80		dummy_stm[i].sw_nchannels	= 0xffff;
 81		dummy_stm[i].packet		= dummy_stm_packet;
 82		dummy_stm[i].link		= dummy_stm_link;
 83
 84		ret = stm_register_device(NULL, &dummy_stm[i], THIS_MODULE);
 85		if (ret)
 86			goto fail_free;
 87	}
 88
 89	dummy_stm_nr = __nr_dummies;
 90
 91	return 0;
 92
 93fail_unregister:
 94	for (i--; i >= 0; i--) {
 95		stm_unregister_device(&dummy_stm[i]);
 96fail_free:
 97		kfree(dummy_stm[i].name);
 98	}
 99
100	return ret;
101
102}
103
104static void dummy_stm_exit(void)
105{
106	int i;
107
108	for (i = 0; i < dummy_stm_nr; i++) {
109		stm_unregister_device(&dummy_stm[i]);
110		kfree(dummy_stm[i].name);
111	}
112}
113
114module_init(dummy_stm_init);
115module_exit(dummy_stm_exit);
116
117MODULE_LICENSE("GPL v2");
118MODULE_DESCRIPTION("dummy_stm device");
119MODULE_AUTHOR("Alexander Shishkin <alexander.shishkin@linux.intel.com>");