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 <[email protected]> --- Documentation/ABI/testing/sysfs-bus-rpmsg | 20 ++++++++++++++ drivers/rpmsg/rpmsg_core.c | 46 +++++++++++++++++++++++++++++-- 2 files changed, 64 insertions(+), 2 deletions(-) diff --git a/Documentation/ABI/testing/sysfs-bus-rpmsg b/Documentation/ABI/testing/sysfs-bus-rpmsg index 189e419..1c8599e 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: January 2018 +KernelVersion: 4.16 +Contact: Ohad Ben-Cohen <[email protected]> +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 dffa3aa..9a25e42 100644 --- a/drivers/rpmsg/rpmsg_core.c +++ b/drivers/rpmsg/rpmsg_core.c @@ -321,11 +321,11 @@ struct device *rpmsg_find_device(struct device *parent, } EXPORT_SYMBOL(rpmsg_find_device); -/* sysfs show configuration fields */ +/* sysfs configuration fields */ #define rpmsg_show_attr(field, path, format_string) \ static ssize_t \ field##_show(struct device *dev, \ - struct device_attribute *attr, char *buf) \ + struct device_attribute *attr, char *buf) \ { \ struct rpmsg_device *rpdev = to_rpmsg_device(dev); \ \ @@ -333,11 +333,52 @@ field##_show(struct device *dev, \ } \ static DEVICE_ATTR_RO(field); +#define rpmsg_string_attr(field, path) \ +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, *cp; \ + \ + new = kstrndup(buf, sz, GFP_KERNEL); \ + if (!new) \ + return -ENOMEM; \ + \ + cp = strchr(new, '\n'); \ + if (cp) \ + *cp = '\0'; \ + \ + device_lock(dev); \ + old = rpdev->path; \ + if (strlen(new)) { \ + rpdev->path = new; \ + } else { \ + kfree(new); \ + rpdev->path = 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->path); \ +} \ +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 +400,7 @@ 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); -- 2.7.4
