Heartbeat stm source may have multiple instances (for connecting to
different stm devices). Each instance will send a periodic test message
over its stm device when it is linked. This can be used for testing stm
class framework, stm device drivers or as a heartbeat over the stm link.
Signed-off-by: Alexander Shishkin <alexander.shish...@linux.intel.com>
---
drivers/hwtracing/stm/Kconfig | 11 ++++
drivers/hwtracing/stm/Makefile | 2 +
drivers/hwtracing/stm/heartbeat.c | 130 ++++++++++++++++++++++++++++++++++++++
3 files changed, 143 insertions(+)
create mode 100644 drivers/hwtracing/stm/heartbeat.c
diff --git a/drivers/hwtracing/stm/Kconfig b/drivers/hwtracing/stm/Kconfig
index e0ac753955..847a39b353 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 f9312c38dd..a9ce3d487e 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 0000000000..0133571b50
--- /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.shish...@linux.intel.com>");
--
2.7.0
