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authorAnup Patel <anup@brainfault.org>2018-03-23 21:41:17 +0530
committerBjorn Andersson <bjorn.andersson@linaro.org>2018-04-25 16:59:53 -0700
commit39e47767ec9b22f844c2a07c9d329256960d4021 (patch)
treed34066f379c86a35f0a249af39046c784b6a850d
parent60cc43fc888428bb2f18f08997432d426a243338 (diff)
rpmsg: Add driver_override device attribute for rpmsg_device
This patch adds "driver_override" device attribute for rpmsg_device which will allow users to explicitly specify the rpmsg_driver to be used via sysfs entry. The "driver_override" device attribute implemented here is very similar to "driver_override" implemented for platform, pci, and amba bus types. One important use-case of "driver_override" device attribute is to force use of rpmsg_chrdev driver for certain rpmsg_device instances. Signed-off-by: Anup Patel <anup@brainfault.org> Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
-rw-r--r--Documentation/ABI/testing/sysfs-bus-rpmsg20
-rw-r--r--drivers/rpmsg/rpmsg_core.c39
2 files changed, 59 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-bus-rpmsg b/Documentation/ABI/testing/sysfs-bus-rpmsg
index 189e419a5a2d..990fcc420935 100644
--- a/Documentation/ABI/testing/sysfs-bus-rpmsg
+++ b/Documentation/ABI/testing/sysfs-bus-rpmsg
@@ -73,3 +73,23 @@ Description:
This sysfs entry tells us whether the channel is a local
server channel that is announced (values are either
true or false).
+
+What: /sys/bus/rpmsg/devices/.../driver_override
+Date: April 2018
+KernelVersion: 4.18
+Contact: Bjorn Andersson <bjorn.andersson@linaro.org>
+Description:
+ Every rpmsg device is a communication channel with a remote
+ processor. Channels are identified by a textual name (see
+ /sys/bus/rpmsg/devices/.../name above) and have a local
+ ("source") rpmsg address, and remote ("destination") rpmsg
+ address.
+
+ The listening entity (or client) which communicates with a
+ remote processor is referred as rpmsg driver. The rpmsg device
+ and rpmsg driver are matched based on rpmsg device name and
+ rpmsg driver ID table.
+
+ This sysfs entry allows the rpmsg driver for a rpmsg device
+ to be specified which will override standard OF, ID table
+ and name matching.
diff --git a/drivers/rpmsg/rpmsg_core.c b/drivers/rpmsg/rpmsg_core.c
index 920a02f0462c..bea7c74e12eb 100644
--- a/drivers/rpmsg/rpmsg_core.c
+++ b/drivers/rpmsg/rpmsg_core.c
@@ -333,11 +333,49 @@ field##_show(struct device *dev, \
} \
static DEVICE_ATTR_RO(field);
+#define rpmsg_string_attr(field, member) \
+static ssize_t \
+field##_store(struct device *dev, struct device_attribute *attr, \
+ const char *buf, size_t sz) \
+{ \
+ struct rpmsg_device *rpdev = to_rpmsg_device(dev); \
+ char *new, *old; \
+ \
+ new = kstrndup(buf, sz, GFP_KERNEL); \
+ if (!new) \
+ return -ENOMEM; \
+ new[strcspn(new, "\n")] = '\0'; \
+ \
+ device_lock(dev); \
+ old = rpdev->member; \
+ if (strlen(new)) { \
+ rpdev->member = new; \
+ } else { \
+ kfree(new); \
+ rpdev->member = NULL; \
+ } \
+ device_unlock(dev); \
+ \
+ kfree(old); \
+ \
+ return sz; \
+} \
+static ssize_t \
+field##_show(struct device *dev, \
+ struct device_attribute *attr, char *buf) \
+{ \
+ struct rpmsg_device *rpdev = to_rpmsg_device(dev); \
+ \
+ return sprintf(buf, "%s\n", rpdev->member); \
+} \
+static DEVICE_ATTR_RW(field)
+
/* for more info, see Documentation/ABI/testing/sysfs-bus-rpmsg */
rpmsg_show_attr(name, id.name, "%s\n");
rpmsg_show_attr(src, src, "0x%x\n");
rpmsg_show_attr(dst, dst, "0x%x\n");
rpmsg_show_attr(announce, announce ? "true" : "false", "%s\n");
+rpmsg_string_attr(driver_override, driver_override);
static ssize_t modalias_show(struct device *dev,
struct device_attribute *attr, char *buf)
@@ -359,6 +397,7 @@ static struct attribute *rpmsg_dev_attrs[] = {
&dev_attr_dst.attr,
&dev_attr_src.attr,
&dev_attr_announce.attr,
+ &dev_attr_driver_override.attr,
NULL,
};
ATTRIBUTE_GROUPS(rpmsg_dev);