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1// SPDX-License-Identifier: GPL-2.02/*3 * A dummy STM device for stm/stm_source class testing.4 * Copyright (c) 2014, Intel Corporation.5 *6 * STM class implements generic infrastructure for System Trace Module devices7 * as defined in MIPI STPv2 specification.8 */9 10#undef DEBUG11#include <linux/kernel.h>12#include <linux/module.h>13#include <linux/slab.h>14#include <linux/stm.h>15#include <uapi/linux/stm.h>16 17static ssize_t notrace18dummy_stm_packet(struct stm_data *stm_data, unsigned int master,19 unsigned int channel, unsigned int packet, unsigned int flags,20 unsigned int size, const unsigned char *payload)21{22#ifdef DEBUG23 u64 pl = 0;24 25 if (payload)26 pl = *(u64 *)payload;27 28 if (size < 8)29 pl &= (1ull << (size * 8)) - 1;30 trace_printk("[%u:%u] [pkt: %x/%x] (%llx)\n", master, channel,31 packet, size, pl);32#endif33 return size;34}35 36#define DUMMY_STM_MAX 3237 38static struct stm_data dummy_stm[DUMMY_STM_MAX];39 40static int nr_dummies = 4;41 42module_param(nr_dummies, int, 0400);43 44static unsigned int fail_mode;45 46module_param(fail_mode, int, 0600);47 48static unsigned int master_min;49 50module_param(master_min, int, 0400);51 52static unsigned int master_max = STP_MASTER_MAX;53 54module_param(master_max, int, 0400);55 56static unsigned int nr_channels = STP_CHANNEL_MAX;57 58module_param(nr_channels, int, 0400);59 60static int dummy_stm_link(struct stm_data *data, unsigned int master,61 unsigned int channel)62{63 if (fail_mode && (channel & fail_mode))64 return -EINVAL;65 66 return 0;67}68 69static int dummy_stm_init(void)70{71 int i, ret = -ENOMEM;72 73 if (nr_dummies < 0 || nr_dummies > DUMMY_STM_MAX)74 return -EINVAL;75 76 if (master_min > master_max ||77 master_max > STP_MASTER_MAX ||78 nr_channels > STP_CHANNEL_MAX)79 return -EINVAL;80 81 for (i = 0; i < nr_dummies; i++) {82 dummy_stm[i].name = kasprintf(GFP_KERNEL, "dummy_stm.%d", i);83 if (!dummy_stm[i].name)84 goto fail_unregister;85 86 dummy_stm[i].sw_start = master_min;87 dummy_stm[i].sw_end = master_max;88 dummy_stm[i].sw_nchannels = nr_channels;89 dummy_stm[i].packet = dummy_stm_packet;90 dummy_stm[i].link = dummy_stm_link;91 92 ret = stm_register_device(NULL, &dummy_stm[i], THIS_MODULE);93 if (ret)94 goto fail_free;95 }96 97 return 0;98 99fail_unregister:100 for (i--; i >= 0; i--) {101 stm_unregister_device(&dummy_stm[i]);102fail_free:103 kfree(dummy_stm[i].name);104 }105 106 return ret;107 108}109 110static void dummy_stm_exit(void)111{112 int i;113 114 for (i = 0; i < nr_dummies; i++) {115 stm_unregister_device(&dummy_stm[i]);116 kfree(dummy_stm[i].name);117 }118}119 120module_init(dummy_stm_init);121module_exit(dummy_stm_exit);122 123MODULE_LICENSE("GPL v2");124MODULE_DESCRIPTION("dummy_stm device");125MODULE_AUTHOR("Alexander Shishkin <alexander.shishkin@linux.intel.com>");126