[PATCH v3 4/8] staging: fsl-mc: root dprc rescan attribute to sync kernel with MC

[Lijun Pan]

Introduce the rescan attribute as a device attribute to
synchronize the fsl-mc bus objects and the MC firmware.

To rescan the root dprc only, e.g.
echo 1 > /sys/bus/fsl-mc/devices/dprc.1/rescan

Signed-off-by: Lijun Pan <Lijun.Pan@xxxxxxxxxxxxx>
---
v3: rebased on top of greg's staging-testing

 drivers/staging/fsl-mc/bus/mc-bus.c |   44 +++++++++++++++++++++++++++++++++++
 1 file changed, 44 insertions(+)

diff --git a/drivers/staging/fsl-mc/bus/mc-bus.c b/drivers/staging/fsl-mc/bus/mc-bus.c
index b828985..b47c3ec 100644
--- a/drivers/staging/fsl-mc/bus/mc-bus.c
+++ b/drivers/staging/fsl-mc/bus/mc-bus.c
@@ -102,10 +102,54 @@ static int fsl_mc_bus_uevent(struct device *dev, struct kobj_uevent_env *env)
 	return 0;
 }
 
+static ssize_t rescan_store(struct device *dev,
+			    struct device_attribute *attr,
+			    const char *buf, size_t count)
+{
+	unsigned long val;
+	unsigned int irq_count;
+	struct fsl_mc_device *root_mc_dev;
+	struct fsl_mc_bus *root_mc_bus;
+
+	if (!is_root_dprc(dev))
+		return -EINVAL;
+
+	root_mc_dev = to_fsl_mc_device(dev);
+	root_mc_bus = to_fsl_mc_bus(root_mc_dev);
+
+	if (kstrtoul(buf, 0, &val) < 0)
+		return -EINVAL;
+
+	if (val) {
+		mutex_lock(&root_mc_bus->scan_mutex);
+		dprc_scan_objects(root_mc_dev, &irq_count);
+		mutex_unlock(&root_mc_bus->scan_mutex);
+	}
+
+	return count;
+}
+
+static DEVICE_ATTR_WO(rescan);
+
+static struct attribute *fsl_mc_dev_attrs[] = {
+	&dev_attr_rescan.attr,
+	NULL,
+};
+
+static const struct attribute_group fsl_mc_dev_group = {
+	.attrs = fsl_mc_dev_attrs,
+};
+
+static const struct attribute_group *fsl_mc_dev_groups[] = {
+	&fsl_mc_dev_group,
+	NULL,
+};
+
 struct bus_type fsl_mc_bus_type = {
 	.name = "fsl-mc",
 	.match = fsl_mc_bus_match,
 	.uevent = fsl_mc_bus_uevent,
+	.dev_groups = fsl_mc_dev_groups,
 };
 EXPORT_SYMBOL_GPL(fsl_mc_bus_type);
 
-- 
1.7.9.5