diff options
Diffstat (limited to 'drivers/hwtracing/stm')
| -rw-r--r-- | drivers/hwtracing/stm/Kconfig | 11 | ||||
| -rw-r--r-- | drivers/hwtracing/stm/Makefile | 2 | ||||
| -rw-r--r-- | drivers/hwtracing/stm/heartbeat.c | 130 |
3 files changed, 143 insertions, 0 deletions
diff --git a/drivers/hwtracing/stm/Kconfig b/drivers/hwtracing/stm/Kconfig index e0ac75395526..847a39b35307 100644 --- a/drivers/hwtracing/stm/Kconfig +++ b/drivers/hwtracing/stm/Kconfig @@ -28,4 +28,15 @@ config STM_SOURCE_CONSOLE If you want to send kernel console messages over STM devices, say Y. +config STM_SOURCE_HEARTBEAT + tristate "Heartbeat over STM devices" + help + This is a kernel space trace source that sends periodic + heartbeat messages to trace hosts over STM devices. It is + also useful for testing stm class drivers and the stm class + framework itself. + + If you want to send heartbeat messages over STM devices, + say Y. + endif diff --git a/drivers/hwtracing/stm/Makefile b/drivers/hwtracing/stm/Makefile index f9312c38dd7a..a9ce3d487e57 100644 --- a/drivers/hwtracing/stm/Makefile +++ b/drivers/hwtracing/stm/Makefile @@ -5,5 +5,7 @@ stm_core-y := core.o policy.o obj-$(CONFIG_STM_DUMMY) += dummy_stm.o obj-$(CONFIG_STM_SOURCE_CONSOLE) += stm_console.o +obj-$(CONFIG_STM_SOURCE_HEARTBEAT) += stm_heartbeat.o stm_console-y := console.o +stm_heartbeat-y := heartbeat.o diff --git a/drivers/hwtracing/stm/heartbeat.c b/drivers/hwtracing/stm/heartbeat.c new file mode 100644 index 000000000000..0133571b506f --- /dev/null +++ b/drivers/hwtracing/stm/heartbeat.c @@ -0,0 +1,130 @@ +/* + * Simple heartbeat STM source driver + * Copyright (c) 2016, Intel Corporation. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + * + * Heartbeat STM source will send repetitive messages over STM devices to a + * trace host. + */ + +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/hrtimer.h> +#include <linux/slab.h> +#include <linux/stm.h> + +#define STM_HEARTBEAT_MAX 32 + +static int nr_devs = 4; +static int interval_ms = 10; + +module_param(nr_devs, int, 0600); +module_param(interval_ms, int, 0600); + +static struct stm_heartbeat { + struct stm_source_data data; + struct hrtimer hrtimer; + unsigned int active; +} stm_heartbeat[STM_HEARTBEAT_MAX]; + +static unsigned int nr_instances; + +static const char str[] = "heartbeat stm source driver is here to serve you"; + +static enum hrtimer_restart stm_heartbeat_hrtimer_handler(struct hrtimer *hr) +{ + struct stm_heartbeat *heartbeat = container_of(hr, struct stm_heartbeat, + hrtimer); + + stm_source_write(&heartbeat->data, 0, str, sizeof str); + if (heartbeat->active) + hrtimer_forward_now(hr, ms_to_ktime(interval_ms)); + + return heartbeat->active ? HRTIMER_RESTART : HRTIMER_NORESTART; +} + +static int stm_heartbeat_link(struct stm_source_data *data) +{ + struct stm_heartbeat *heartbeat = + container_of(data, struct stm_heartbeat, data); + + heartbeat->active = 1; + hrtimer_start(&heartbeat->hrtimer, ms_to_ktime(interval_ms), + HRTIMER_MODE_ABS); + + return 0; +} + +static void stm_heartbeat_unlink(struct stm_source_data *data) +{ + struct stm_heartbeat *heartbeat = + container_of(data, struct stm_heartbeat, data); + + heartbeat->active = 0; + hrtimer_cancel(&heartbeat->hrtimer); +} + +static int stm_heartbeat_init(void) +{ + int i, ret = -ENOMEM, __nr_instances = ACCESS_ONCE(nr_devs); + + if (__nr_instances < 0 || __nr_instances > STM_HEARTBEAT_MAX) + return -EINVAL; + + for (i = 0; i < __nr_instances; i++) { + stm_heartbeat[i].data.name = + kasprintf(GFP_KERNEL, "heartbeat.%d", i); + if (!stm_heartbeat[i].data.name) + goto fail_unregister; + + stm_heartbeat[i].data.nr_chans = 1; + stm_heartbeat[i].data.link = stm_heartbeat_link; + stm_heartbeat[i].data.unlink = stm_heartbeat_unlink; + hrtimer_init(&stm_heartbeat[i].hrtimer, CLOCK_MONOTONIC, + HRTIMER_MODE_ABS); + stm_heartbeat[i].hrtimer.function = + stm_heartbeat_hrtimer_handler; + + ret = stm_source_register_device(NULL, &stm_heartbeat[i].data); + if (ret) + goto fail_free; + } + + nr_instances = __nr_instances; + + return 0; + +fail_unregister: + for (i--; i >= 0; i--) { + stm_source_unregister_device(&stm_heartbeat[i].data); +fail_free: + kfree(stm_heartbeat[i].data.name); + } + + return ret; +} + +static void stm_heartbeat_exit(void) +{ + int i; + + for (i = 0; i < nr_instances; i++) { + stm_source_unregister_device(&stm_heartbeat[i].data); + kfree(stm_heartbeat[i].data.name); + } +} + +module_init(stm_heartbeat_init); +module_exit(stm_heartbeat_exit); + +MODULE_LICENSE("GPL v2"); +MODULE_DESCRIPTION("stm_heartbeat driver"); +MODULE_AUTHOR("Alexander Shishkin <alexander.shishkin@linux.intel.com>"); |