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Subject[PATCH 7/7] samples/amp: add an rpmsg driver sample
Date
Add an rpmsg driver sample, which demonstrates how to communicate with
an AMP-configured remote processor over the rpmsg bus.

The driver repeatedly sends a "Hello World!" message to the remote
processor.

Note that once probed, the driver can immediately start sending messages
using the rpmsg_send() API, without having to worry about creating endpoints
or allocating rpmsg addresses: all that work is done by the rpmsg bus,
and the required information is already embedded in the rpmsg channel
that the driver is probed with.

Designed with Brian Swetland <swetland@google.com>.

Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com>
Cc: Brian Swetland <swetland@google.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Grant Likely <grant.likely@secretlab.ca>
Cc: Tony Lindgren <tony@atomide.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Greg KH <greg@kroah.com>
Cc: Stephen Boyd <sboyd@codeaurora.org>
---
samples/Kconfig | 8 +++
samples/Makefile | 2 +-
samples/amp/Makefile | 1 +
samples/amp/rpmsg_client_sample.c | 100 +++++++++++++++++++++++++++++++++++++
4 files changed, 110 insertions(+), 1 deletions(-)
create mode 100644 samples/amp/Makefile
create mode 100644 samples/amp/rpmsg_client_sample.c

diff --git a/samples/Kconfig b/samples/Kconfig
index 96a7572..997ddd3 100644
--- a/samples/Kconfig
+++ b/samples/Kconfig
@@ -67,4 +67,12 @@ config SAMPLE_HIDRAW
help
Build an example of how to use hidraw from userspace.

+config SAMPLE_RPMSG_CLIENT
+ tristate "Build rpmsg client sample -- loadable modules only"
+ depends on RPMSG && m
+ help
+ Build an rpmsg client sample driver, which demonstrates how
+ to communicate with an AMP-configured remote processor over
+ the rpmsg bus.
+
endif # SAMPLES
diff --git a/samples/Makefile b/samples/Makefile
index 6280817..040f424 100644
--- a/samples/Makefile
+++ b/samples/Makefile
@@ -1,4 +1,4 @@
# Makefile for Linux samples code

obj-$(CONFIG_SAMPLES) += kobject/ kprobes/ tracepoints/ trace_events/ \
- hw_breakpoint/ kfifo/ kdb/ hidraw/
+ hw_breakpoint/ kfifo/ kdb/ hidraw/ amp/
diff --git a/samples/amp/Makefile b/samples/amp/Makefile
new file mode 100644
index 0000000..2d4973c
--- /dev/null
+++ b/samples/amp/Makefile
@@ -0,0 +1 @@
+obj-$(CONFIG_SAMPLE_RPMSG_CLIENT) += rpmsg_client_sample.o
diff --git a/samples/amp/rpmsg_client_sample.c b/samples/amp/rpmsg_client_sample.c
new file mode 100644
index 0000000..7b23380
--- /dev/null
+++ b/samples/amp/rpmsg_client_sample.c
@@ -0,0 +1,100 @@
+/*
+ * Remote processor messaging - sample client driver
+ *
+ * Copyright (C) 2011 Texas Instruments, Inc.
+ * Copyright (C) 2011 Google, Inc.
+ *
+ * Ohad Ben-Cohen <ohad@wizery.com>
+ * Brian Swetland <swetland@google.com>
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that 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/amp/rpmsg.h>
+
+#define MSG "hello world!"
+#define MSG_LIMIT 100
+
+static void rpmsg_sample_cb(struct rpmsg_channel *rpdev, void *data, int len,
+ void *priv, u32 src)
+{
+ int ret;
+ static int rx_count;
+
+ dev_info(&rpdev->dev, "incoming msg %d (src: 0x%x)\n", ++rx_count, src);
+
+ print_hex_dump(KERN_DEBUG, __func__, DUMP_PREFIX_NONE, 16, 1,
+ data, len, true);
+
+ /* samples should not live forever */
+ if (rx_count >= MSG_LIMIT) {
+ dev_info(&rpdev->dev, "goodbye!\n");
+ return;
+ }
+
+ /* send a new message now */
+ ret = rpmsg_send(rpdev, MSG, strlen(MSG));
+ if (ret)
+ dev_err(&rpdev->dev, "rpmsg_send failed: %d\n", ret);
+}
+
+static int rpmsg_sample_probe(struct rpmsg_channel *rpdev)
+{
+ int ret;
+
+ dev_info(&rpdev->dev, "new channel: 0x%x -> 0x%x!\n",
+ rpdev->src, rpdev->dst);
+
+ /* send a message to our remote processor */
+ ret = rpmsg_send(rpdev, MSG, strlen(MSG));
+ if (ret) {
+ dev_err(&rpdev->dev, "rpmsg_send failed: %d\n", ret);
+ return ret;
+ }
+
+ return 0;
+}
+
+static void __devexit rpmsg_sample_remove(struct rpmsg_channel *rpdev)
+{
+ dev_info(&rpdev->dev, "rpmsg sample client driver is removed\n");
+}
+
+static struct rpmsg_device_id rpmsg_driver_sample_id_table[] = {
+ { .name = "rpmsg-client-sample" },
+ { },
+};
+MODULE_DEVICE_TABLE(rpmsg, rpmsg_driver_sample_id_table);
+
+static struct rpmsg_driver rpmsg_sample_client = {
+ .drv.name = KBUILD_MODNAME,
+ .drv.owner = THIS_MODULE,
+ .id_table = rpmsg_driver_sample_id_table,
+ .probe = rpmsg_sample_probe,
+ .callback = rpmsg_sample_cb,
+ .remove = __devexit_p(rpmsg_sample_remove),
+};
+
+static int __init rpmsg_client_sample_init(void)
+{
+ return register_rpmsg_driver(&rpmsg_sample_client);
+}
+module_init(rpmsg_client_sample_init);
+
+static void __exit rpmsg_client_sample_fini(void)
+{
+ unregister_rpmsg_driver(&rpmsg_sample_client);
+}
+module_exit(rpmsg_client_sample_fini);
+
+MODULE_DESCRIPTION("Remote processor messaging sample client driver");
+MODULE_LICENSE("GPL v2");
--
1.7.5.4


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