bus: fsl-mc: add bus rescan attribute

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

Acked-by: Laurentiu Tudor <laurentiu.tudor@nxp.com>
Signed-off-by: Ioana Ciornei <ioana.ciornei@nxp.com>
Link: https://lore.kernel.org/r/20210114170752.2927915-5-ciorneiioana@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 41 insertions, 0 deletions

diff --git a/drivers/bus/fsl-mc/fsl-mc-bus.c b/drivers/bus/fsl-mc/fsl-mc-bus.c
index 5a8fc68d6109..ee3e6252ffc3 100644
--- a/drivers/bus/fsl-mc/fsl-mc-bus.c
+++ b/drivers/bus/fsl-mc/fsl-mc-bus.c
@@ -208,12 +208,53 @@ static struct attribute *fsl_mc_dev_attrs[] = {
 
 ATTRIBUTE_GROUPS(fsl_mc_dev);
 
+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 (!fsl_mc_is_root_dprc(dev))
+		goto exit;
+
+	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, NULL);
+	mutex_unlock(&root_mc_bus->scan_mutex);
+
+exit:
+	return 0;
+}
+
+static ssize_t 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_WO(rescan);
+
+static struct attribute *fsl_mc_bus_attrs[] = {
+	&bus_attr_rescan.attr,
+	NULL,
+};
+
+ATTRIBUTE_GROUPS(fsl_mc_bus);
+
 struct bus_type fsl_mc_bus_type = {
 	.name = "fsl-mc",
 	.match = fsl_mc_bus_match,
 	.uevent = fsl_mc_bus_uevent,
 	.dma_configure  = fsl_mc_dma_configure,
 	.dev_groups = fsl_mc_dev_groups,
+	.bus_groups = fsl_mc_bus_groups,
 };
 EXPORT_SYMBOL_GPL(fsl_mc_bus_type);