[PATCH 4/5] staging: fsl-mc: bus rescan attribute to sync kernel with MC

[Lijun Pan <Lijun.Pan@freescale.com>]

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

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

Signed-off-by: Lijun Pan <Lijun.Pan@freescale.com>
---
 drivers/staging/fsl-mc/bus/mc-bus.c | 46 +++++++++++++++++++++++++++++++++++++
 1 file changed, 46 insertions(+)

diff --git a/drivers/staging/fsl-mc/bus/mc-bus.c b/drivers/staging/fsl-mc/bus/mc-bus.c
index 33a56ad..f1baad7 100644
--- a/drivers/staging/fsl-mc/bus/mc-bus.c
+++ b/drivers/staging/fsl-mc/bus/mc-bus.c
@@ -144,11 +144,57 @@ static const struct attribute_group *fsl_mc_dev_groups[] = {
 	NULL,
 };
 
+static int scan_fsl_mc_bus(struct device *dev, void *data)
+{
+	struct fsl_mc_device *root_mc_dev;
+	struct fsl_mc_bus *root_mc_bus;
+
+	if (is_root_dprc(dev)) {
+		root_mc_dev = to_fsl_mc_device(dev);
+		root_mc_bus = to_fsl_mc_bus(root_mc_dev);
+		mutex_lock(&root_mc_bus->scan_mutex);
+		dprc_scan_objects(root_mc_dev);
+		mutex_unlock(&root_mc_bus->scan_mutex);
+	}
+
+	return 0;
+}
+
+static ssize_t bus_rescan_store(struct bus_type *bus,
+			    const char *buf, size_t count)
+{
+	unsigned long val;
+
+	if (kstrtoul(buf, 0, &val) < 0)
+		return -EINVAL;
+
+	if (val)
+		bus_for_each_dev(bus, NULL, NULL, scan_fsl_mc_bus);
+
+	return count;
+}
+static BUS_ATTR(rescan, (S_IWUSR|S_IWGRP), NULL, bus_rescan_store);
+
+static struct attribute *fsl_mc_bus_attrs[] = {
+	&bus_attr_rescan.attr,
+	NULL,
+};
+
+static const struct attribute_group fsl_mc_bus_group = {
+	.attrs = fsl_mc_bus_attrs,
+};
+
+static const struct attribute_group *fsl_mc_bus_groups[] = {
+	&fsl_mc_bus_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,
+	.bus_groups = fsl_mc_bus_groups,
 };
 EXPORT_SYMBOL_GPL(fsl_mc_bus_type);
 
-- 
2.3.3