From: Mathieu Poirier <mathieu.poir...@linaro.org>
This patch adds a driver that models itself as an stm_source and
who's sole purpose is to export an interface to the rest of the
kernel. Once the stm and stm_source have been linked via sysfs,
everything that is passed to the interface will endup in the STM
trace engine.
Signed-off-by: Mathieu Poirier <mathieu.poir...@linaro.org>
Signed-off-by: Chunyan Zhang <zhang.chun...@linaro.org>
---
drivers/hwtracing/stm/Kconfig | 11 ++++++++
drivers/hwtracing/stm/Makefile | 2 ++
drivers/hwtracing/stm/stm_trace_event.c | 46 +++++++++++++++++++++++++++++++++
3 files changed, 59 insertions(+)
create mode 100644 drivers/hwtracing/stm/stm_trace_event.c
diff --git a/drivers/hwtracing/stm/Kconfig b/drivers/hwtracing/stm/Kconfig
index 583c222..ca3b9a9 100644
--- a/drivers/hwtracing/stm/Kconfig
+++ b/drivers/hwtracing/stm/Kconfig
@@ -23,3 +23,14 @@ config STM_SOURCE_CONSOLE
If you want to send kernel console messages over STM devices,
say Y.
+
+config TRACE_EVENT_STM
+ tristate "Redirect/copy the output from kernel trace event to STM
engine"
+ depends on STM
+ help
+ This option can be used to redirect or copy the output from kernel
trace
+ event to STM engine. Enabling this option will introduce a slight
+ timing effect.
+
+ If you want to send kernel trace event messages over STM devices,
+ say Y.
diff --git a/drivers/hwtracing/stm/Makefile b/drivers/hwtracing/stm/Makefile
index f9312c3..110a75a 100644
--- a/drivers/hwtracing/stm/Makefile
+++ b/drivers/hwtracing/stm/Makefile
@@ -7,3 +7,5 @@ obj-$(CONFIG_STM_DUMMY) += dummy_stm.o
obj-$(CONFIG_STM_SOURCE_CONSOLE) += stm_console.o
stm_console-y := console.o
+
+obj-$(CONFIG_TRACE_EVENT_STM) += stm_trace_event.o
diff --git a/drivers/hwtracing/stm/stm_trace_event.c
b/drivers/hwtracing/stm/stm_trace_event.c
new file mode 100644
index 0000000..bc77dae
--- /dev/null
+++ b/drivers/hwtracing/stm/stm_trace_event.c
@@ -0,0 +1,46 @@
+/*
+ * Simple kernel driver to link kernel trace event and an STM device
+ * Copyright (c) 2015, Linaro Ltd.
+ *
+ * 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.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/console.h>
+#include <linux/stm.h>
+
+static struct stm_source_data stm_trace_event_data = {
+ .name = "stm_trace_event",
+ .nr_chans = 1,
+};
+
+void stm_trace_event_write(const char *buf, unsigned len)
+{
+ stm_source_write(&stm_trace_event_data, 0, buf, len);
+}
+
+static int __init stm_trace_event_init(void)
+{
+ return stm_source_register_device(NULL, &stm_trace_event_data);
+}
+
+static void __exit stm_trace_event_exit(void)
+{
+ stm_source_unregister_device(&stm_trace_event_data);
+}
+
+module_init(stm_trace_event_init);
+module_exit(stm_trace_event_exit);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("stm_trace_event driver");
+MODULE_AUTHOR("Mathieu Poirier <mathieu.poir...@linaro.org>");
--
1.9.1
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