[PATCH v2 03/11] stm class: dummy_stm: Add dummy driver for testing stm class

[Alexander Shishkin]

This is a simple module that pretends to be an stm device and discards
all the data that comes in. Useful for testing stm class and its users.

Cc: Pratik Patel <pratikp@xxxxxxxxxxxxxx>
Cc: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>
Signed-off-by: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
---
 drivers/hwtracing/stm/Kconfig     |  8 ++++++
 drivers/hwtracing/stm/Makefile    |  2 ++
 drivers/hwtracing/stm/dummy_stm.c | 60 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 70 insertions(+)
 create mode 100644 drivers/hwtracing/stm/dummy_stm.c

diff --git a/drivers/hwtracing/stm/Kconfig b/drivers/hwtracing/stm/Kconfig
index 90ed327461..4fdb8f46d2 100644
--- a/drivers/hwtracing/stm/Kconfig
+++ b/drivers/hwtracing/stm/Kconfig
@@ -6,3 +6,11 @@ config STM
 	  Examples of such devices are Intel Trace Hub and Coresight STM.
 
 	  Say Y here to enable System Trace Module device support.
+
+config STM_DUMMY
+	tristate "Dummy STM driver"
+	help
+	  This is a simple dummy device that pretends to be an stm device
+	  and discards your data. Use for stm class testing.
+
+	  If you don't know what this is, say N.
diff --git a/drivers/hwtracing/stm/Makefile b/drivers/hwtracing/stm/Makefile
index adec701649..1b2725fd04 100644
--- a/drivers/hwtracing/stm/Makefile
+++ b/drivers/hwtracing/stm/Makefile
@@ -1,3 +1,5 @@
 obj-$(CONFIG_STM)	+= stm_core.o
 
 stm_core-y		:= core.o policy.o
+
+obj-$(CONFIG_STM_DUMMY)	+= dummy_stm.o
diff --git a/drivers/hwtracing/stm/dummy_stm.c b/drivers/hwtracing/stm/dummy_stm.c
new file mode 100644
index 0000000000..40bfb7db56
--- /dev/null
+++ b/drivers/hwtracing/stm/dummy_stm.c
@@ -0,0 +1,60 @@
+/*
+ * A dummy STM device for stm/stm_source class testing.
+ * Copyright (c) 2014, 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.
+ *
+ * STM class implements generic infrastructure for  System Trace Module devices
+ * as defined in MIPI STPv2 specification.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/stm.h>
+
+static ssize_t
+dummy_stm_write(struct stm_data *stm_data, unsigned int master,
+		unsigned int channel, const char *buf, size_t count)
+{
+#ifdef DEBUG
+	char *s = kstrndup(buf, count, GFP_ATOMIC);
+
+	trace_printk("[%u:%u] [%s] (%lu)\n", master, channel, s, count);
+	kfree(s);
+#endif
+
+	return count;
+}
+
+static struct stm_data dummy_stm = {
+	.name		= "dummy_stm",
+	.sw_start	= 0x0000,
+	.sw_end		= 0xffff,
+	.sw_nchannels	= 0xffff,
+	.write		= dummy_stm_write,
+};
+
+static int dummy_stm_init(void)
+{
+	return stm_register_device(NULL, &dummy_stm, THIS_MODULE);
+}
+
+static void dummy_stm_exit(void)
+{
+	stm_unregister_device(&dummy_stm);
+}
+
+module_init(dummy_stm_init);
+module_exit(dummy_stm_exit);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("dummy_stm device");
+MODULE_AUTHOR("Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>");
-- 
2.1.4

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