firmware: arm_scmi: Cleanup the core driver removal callback

[ Upstream commit 3f4071cbd2063b917486d1047a4da47718215fee ]

Platform drivers .remove callbacks are not supposed to fail and report
errors. Such errors are indeed ignored by the core platform drivers
and the driver unbind process is anyway completed.

The SCMI core platform driver as it is now, instead, bails out reporting
an error in case of an explicit unbind request.

Fix the removal path by adding proper device links between the core SCMI
device and the SCMI protocol devices so that a full SCMI stack unbind is
triggered when the core driver is removed. The remove process does not
bail out anymore on the anomalous conditions triggered by an explicit
unbind but the user is still warned.

Reported-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
Link: https://lore.kernel.org/r/20221028140833.280091-1-cristian.marussi@arm.com
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/firmware/arm_scmi/bus.c b/drivers/firmware/arm_scmi/bus.c
index f6fe723ab869e4836ee341d046585dd95a908220..7c1c0951e562d120bb1b29b7eaae365d95ef9f90 100644 (file)
--- a/drivers/firmware/arm_scmi/bus.c
+++ b/drivers/firmware/arm_scmi/bus.c
@@ -216,9 +216,20 @@ void scmi_device_destroy(struct scmi_device *scmi_dev)
        device_unregister(&scmi_dev->dev);
 }
 
+void scmi_device_link_add(struct device *consumer, struct device *supplier)
+{
+       struct device_link *link;
+
+       link = device_link_add(consumer, supplier, DL_FLAG_AUTOREMOVE_CONSUMER);
+
+       WARN_ON(!link);
+}
+
 void scmi_set_handle(struct scmi_device *scmi_dev)
 {
        scmi_dev->handle = scmi_handle_get(&scmi_dev->dev);
+       if (scmi_dev->handle)
+               scmi_device_link_add(&scmi_dev->dev, scmi_dev->handle->dev);
 }
 
 int scmi_protocol_register(const struct scmi_protocol *proto)

diff --git a/drivers/firmware/arm_scmi/common.h b/drivers/firmware/arm_scmi/common.h
index dea1bfbe10527c593caff1934c903475ead6ecd1..b9f5829c0c4ddb2bca3f29397781a1ce23004001 100644 (file)
--- a/drivers/firmware/arm_scmi/common.h
+++ b/drivers/firmware/arm_scmi/common.h
@@ -272,6 +272,7 @@ struct scmi_xfer_ops {
 struct scmi_revision_info *
 scmi_revision_area_get(const struct scmi_protocol_handle *ph);
 int scmi_handle_put(const struct scmi_handle *handle);
+void scmi_device_link_add(struct device *consumer, struct device *supplier);
 struct scmi_handle *scmi_handle_get(struct device *dev);
 void scmi_set_handle(struct scmi_device *scmi_dev);
 void scmi_setup_protocol_implemented(const struct scmi_protocol_handle *ph,

diff --git a/drivers/firmware/arm_scmi/driver.c b/drivers/firmware/arm_scmi/driver.c
index 16569af4a2ba84ae6af54304adb71a6f2f42d01b..a8ff4c9508b77fb1a4d54456bb1d3bac0a676be5 100644 (file)
--- a/drivers/firmware/arm_scmi/driver.c
+++ b/drivers/firmware/arm_scmi/driver.c
@@ -1731,10 +1731,16 @@ int scmi_protocol_device_request(const struct scmi_device_id *id_table)
                        sdev = scmi_get_protocol_device(child, info,
                                                        id_table->protocol_id,
                                                        id_table->name);
-                       /* Set handle if not already set: device existed */
-                       if (sdev && !sdev->handle)
-                               sdev->handle =
-                                       scmi_handle_get_from_info_unlocked(info);
+                       if (sdev) {
+                               /* Set handle if not already set: device existed */
+                               if (!sdev->handle)
+                                       sdev->handle =
+                                               scmi_handle_get_from_info_unlocked(info);
+                               /* Relink consumer and suppliers */
+                               if (sdev->handle)
+                                       scmi_device_link_add(&sdev->dev,
+                                                            sdev->handle->dev);
+                       }
                } else {
                        dev_err(info->dev,
                                "Failed. SCMI protocol %d not active.\n",
@@ -1920,20 +1926,17 @@ void scmi_free_channel(struct scmi_chan_info *cinfo, struct idr *idr, int id)
 
 static int scmi_remove(struct platform_device *pdev)
 {
-       int ret = 0, id;
+       int ret, id;
        struct scmi_info *info = platform_get_drvdata(pdev);
        struct device_node *child;
 
        mutex_lock(&scmi_list_mutex);
        if (info->users)
-               ret = -EBUSY;
-       else
-               list_del(&info->node);
+               dev_warn(&pdev->dev,
+                        "Still active SCMI users will be forcibly unbound.\n");
+       list_del(&info->node);
        mutex_unlock(&scmi_list_mutex);
 
-       if (ret)
-               return ret;
-
        scmi_notification_exit(&info->handle);
 
        mutex_lock(&info->protocols_mtx);
@@ -1945,7 +1948,11 @@ static int scmi_remove(struct platform_device *pdev)
        idr_destroy(&info->active_protocols);
 
        /* Safe to free channels since no more users */
-       return scmi_cleanup_txrx_channels(info);
+       ret = scmi_cleanup_txrx_channels(info);
+       if (ret)
+               dev_warn(&pdev->dev, "Failed to cleanup SCMI channels.\n");
+
+       return 0;
 }
 
 static ssize_t protocol_version_show(struct device *dev,