1 files changed, 153 insertions, 116 deletions

diff --git a/drivers/platform/surface/surface_aggregator_registry.c b/drivers/platform/surface/surface_aggregator_registry.c
index 9f630e890ff7..09cbeee2428b 100644
--- a/drivers/platform/surface/surface_aggregator_registry.c
+++ b/drivers/platform/surface/surface_aggregator_registry.c
@@ -308,30 +308,159 @@ err:
 }
 
 
-/* -- SSAM base-hub driver. ------------------------------------------------- */
+/* -- SSAM generic subsystem hub driver framework. -------------------------- */
 
-/*
- * Some devices (especially battery) may need a bit of time to be fully usable
- * after being (re-)connected. This delay has been determined via
- * experimentation.
- */
-#define SSAM_BASE_UPDATE_CONNECT_DELAY		msecs_to_jiffies(2500)
+enum ssam_hub_state {
+	SSAM_HUB_UNINITIALIZED,		/* Only set during initialization. */
+	SSAM_HUB_CONNECTED,
+	SSAM_HUB_DISCONNECTED,
+};
 
-enum ssam_base_hub_state {
-	SSAM_BASE_HUB_UNINITIALIZED,
-	SSAM_BASE_HUB_CONNECTED,
-	SSAM_BASE_HUB_DISCONNECTED,
+enum ssam_hub_flags {
+	SSAM_HUB_HOT_REMOVED,
 };
 
-struct ssam_base_hub {
+struct ssam_hub {
 	struct ssam_device *sdev;
 
-	enum ssam_base_hub_state state;
+	enum ssam_hub_state state;
+	unsigned long flags;
+
 	struct delayed_work update_work;
+	unsigned long connect_delay;
 
 	struct ssam_event_notifier notif;
+
+	int (*get_state)(struct ssam_hub *hub, enum ssam_hub_state *state);
 };
 
+static void ssam_hub_update_workfn(struct work_struct *work)
+{
+	struct ssam_hub *hub = container_of(work, struct ssam_hub, update_work.work);
+	struct fwnode_handle *node = dev_fwnode(&hub->sdev->dev);
+	enum ssam_hub_state state;
+	int status = 0;
+
+	status = hub->get_state(hub, &state);
+	if (status)
+		return;
+
+	/*
+	 * There is a small possibility that hub devices were hot-removed and
+	 * re-added before we were able to remove them here. In that case, both
+	 * the state returned by get_state() and the state of the hub will
+	 * equal SSAM_HUB_CONNECTED and we would bail early below, which would
+	 * leave child devices without proper (re-)initialization and the
+	 * hot-remove flag set.
+	 *
+	 * Therefore, we check whether devices have been hot-removed via an
+	 * additional flag on the hub and, in this case, override the returned
+	 * hub state. In case of a missed disconnect (i.e. get_state returned
+	 * "connected"), we further need to re-schedule this work (with the
+	 * appropriate delay) as the actual connect work submission might have
+	 * been merged with this one.
+	 *
+	 * This then leads to one of two cases: Either we submit an unnecessary
+	 * work item (which will get ignored via either the queue or the state
+	 * checks) or, in the unlikely case that the work is actually required,
+	 * double the normal connect delay.
+	 */
+	if (test_and_clear_bit(SSAM_HUB_HOT_REMOVED, &hub->flags)) {
+		if (state == SSAM_HUB_CONNECTED)
+			schedule_delayed_work(&hub->update_work, hub->connect_delay);
+
+		state = SSAM_HUB_DISCONNECTED;
+	}
+
+	if (hub->state == state)
+		return;
+	hub->state = state;
+
+	if (hub->state == SSAM_HUB_CONNECTED)
+		status = ssam_hub_register_clients(&hub->sdev->dev, hub->sdev->ctrl, node);
+	else
+		ssam_remove_clients(&hub->sdev->dev);
+
+	if (status)
+		dev_err(&hub->sdev->dev, "failed to update hub child devices: %d\n", status);
+}
+
+static int ssam_hub_mark_hot_removed(struct device *dev, void *_data)
+{
+	struct ssam_device *sdev = to_ssam_device(dev);
+
+	if (is_ssam_device(dev))
+		ssam_device_mark_hot_removed(sdev);
+
+	return 0;
+}
+
+static void ssam_hub_update(struct ssam_hub *hub, bool connected)
+{
+	unsigned long delay;
+
+	/* Mark devices as hot-removed before we remove any. */
+	if (!connected) {
+		set_bit(SSAM_HUB_HOT_REMOVED, &hub->flags);
+		device_for_each_child_reverse(&hub->sdev->dev, NULL, ssam_hub_mark_hot_removed);
+	}
+
+	/*
+	 * Delay update when the base/keyboard cover is being connected to give
+	 * devices/EC some time to set up.
+	 */
+	delay = connected ? hub->connect_delay : 0;
+
+	schedule_delayed_work(&hub->update_work, delay);
+}
+
+static int __maybe_unused ssam_hub_resume(struct device *dev)
+{
+	struct ssam_hub *hub = dev_get_drvdata(dev);
+
+	schedule_delayed_work(&hub->update_work, 0);
+	return 0;
+}
+static SIMPLE_DEV_PM_OPS(ssam_hub_pm_ops, NULL, ssam_hub_resume);
+
+static int ssam_hub_setup(struct ssam_device *sdev, struct ssam_hub *hub)
+{
+	int status;
+
+	hub->sdev = sdev;
+	hub->state = SSAM_HUB_UNINITIALIZED;
+
+	INIT_DELAYED_WORK(&hub->update_work, ssam_hub_update_workfn);
+
+	ssam_device_set_drvdata(sdev, hub);
+
+	status = ssam_device_notifier_register(sdev, &hub->notif);
+	if (status)
+		return status;
+
+	schedule_delayed_work(&hub->update_work, 0);
+	return 0;
+}
+
+static void ssam_hub_remove(struct ssam_device *sdev)
+{
+	struct ssam_hub *hub = ssam_device_get_drvdata(sdev);
+
+	ssam_device_notifier_unregister(sdev, &hub->notif);
+	cancel_delayed_work_sync(&hub->update_work);
+	ssam_remove_clients(&sdev->dev);
+}
+
+
+/* -- SSAM base-hub driver. ------------------------------------------------- */
+
+/*
+ * Some devices (especially battery) may need a bit of time to be fully usable
+ * after being (re-)connected. This delay has been determined via
+ * experimentation.
+ */
+#define SSAM_BASE_UPDATE_CONNECT_DELAY		msecs_to_jiffies(2500)
+
 SSAM_DEFINE_SYNC_REQUEST_R(ssam_bas_query_opmode, u8, {
 	.target_category = SSAM_SSH_TC_BAS,
 	.target_id       = 0x01,
@@ -342,7 +471,7 @@ SSAM_DEFINE_SYNC_REQUEST_R(ssam_bas_query_opmode, u8, {
 #define SSAM_BAS_OPMODE_TABLET		0x00
 #define SSAM_EVENT_BAS_CID_CONNECTION	0x0c
 
-static int ssam_base_hub_query_state(struct ssam_base_hub *hub, enum ssam_base_hub_state *state)
+static int ssam_base_hub_query_state(struct ssam_hub *hub, enum ssam_hub_state *state)
 {
 	u8 opmode;
 	int status;
@@ -354,62 +483,16 @@ static int ssam_base_hub_query_state(struct ssam_base_hub *hub, enum ssam_base_h
 	}
 
 	if (opmode != SSAM_BAS_OPMODE_TABLET)
-		*state = SSAM_BASE_HUB_CONNECTED;
+		*state = SSAM_HUB_CONNECTED;
 	else
-		*state = SSAM_BASE_HUB_DISCONNECTED;
+		*state = SSAM_HUB_DISCONNECTED;
 
 	return 0;
 }
 
-static ssize_t ssam_base_hub_state_show(struct device *dev, struct device_attribute *attr,
-					char *buf)
-{
-	struct ssam_base_hub *hub = dev_get_drvdata(dev);
-	bool connected = hub->state == SSAM_BASE_HUB_CONNECTED;
-
-	return sysfs_emit(buf, "%d\n", connected);
-}
-
-static struct device_attribute ssam_base_hub_attr_state =
-	__ATTR(state, 0444, ssam_base_hub_state_show, NULL);
-
-static struct attribute *ssam_base_hub_attrs[] = {
-	&ssam_base_hub_attr_state.attr,
-	NULL,
-};
-
-static const struct attribute_group ssam_base_hub_group = {
-	.attrs = ssam_base_hub_attrs,
-};
-
-static void ssam_base_hub_update_workfn(struct work_struct *work)
-{
-	struct ssam_base_hub *hub = container_of(work, struct ssam_base_hub, update_work.work);
-	struct fwnode_handle *node = dev_fwnode(&hub->sdev->dev);
-	enum ssam_base_hub_state state;
-	int status = 0;
-
-	status = ssam_base_hub_query_state(hub, &state);
-	if (status)
-		return;
-
-	if (hub->state == state)
-		return;
-	hub->state = state;
-
-	if (hub->state == SSAM_BASE_HUB_CONNECTED)
-		status = ssam_hub_register_clients(&hub->sdev->dev, hub->sdev->ctrl, node);
-	else
-		ssam_remove_clients(&hub->sdev->dev);
-
-	if (status)
-		dev_err(&hub->sdev->dev, "failed to update base-hub devices: %d\n", status);
-}
-
 static u32 ssam_base_hub_notif(struct ssam_event_notifier *nf, const struct ssam_event *event)
 {
-	struct ssam_base_hub *hub = container_of(nf, struct ssam_base_hub, notif);
-	unsigned long delay;
+	struct ssam_hub *hub = container_of(nf, struct ssam_hub, notif);
 
 	if (event->command_id != SSAM_EVENT_BAS_CID_CONNECTION)
 		return 0;
@@ -419,13 +502,7 @@ static u32 ssam_base_hub_notif(struct ssam_event_notifier *nf, const struct ssam
 		return 0;
 	}
 
-	/*
-	 * Delay update when the base is being connected to give devices/EC
-	 * some time to set up.
-	 */
-	delay = event->data[0] ? SSAM_BASE_UPDATE_CONNECT_DELAY : 0;
-
-	schedule_delayed_work(&hub->update_work, delay);
+	ssam_hub_update(hub, event->data[0]);
 
 	/*
 	 * Do not return SSAM_NOTIF_HANDLED: The event should be picked up and
@@ -435,27 +512,14 @@ static u32 ssam_base_hub_notif(struct ssam_event_notifier *nf, const struct ssam
 	return 0;
 }
 
-static int __maybe_unused ssam_base_hub_resume(struct device *dev)
-{
-	struct ssam_base_hub *hub = dev_get_drvdata(dev);
-
-	schedule_delayed_work(&hub->update_work, 0);
-	return 0;
-}
-static SIMPLE_DEV_PM_OPS(ssam_base_hub_pm_ops, NULL, ssam_base_hub_resume);
-
 static int ssam_base_hub_probe(struct ssam_device *sdev)
 {
-	struct ssam_base_hub *hub;
-	int status;
+	struct ssam_hub *hub;
 
 	hub = devm_kzalloc(&sdev->dev, sizeof(*hub), GFP_KERNEL);
 	if (!hub)
 		return -ENOMEM;
 
-	hub->sdev = sdev;
-	hub->state = SSAM_BASE_HUB_UNINITIALIZED;
-
 	hub->notif.base.priority = INT_MAX;  /* This notifier should run first. */
 	hub->notif.base.fn = ssam_base_hub_notif;
 	hub->notif.event.reg = SSAM_EVENT_REGISTRY_SAM;
@@ -464,37 +528,10 @@ static int ssam_base_hub_probe(struct ssam_device *sdev)
 	hub->notif.event.mask = SSAM_EVENT_MASK_NONE;
 	hub->notif.event.flags = SSAM_EVENT_SEQUENCED;
 
-	INIT_DELAYED_WORK(&hub->update_work, ssam_base_hub_update_workfn);
-
-	ssam_device_set_drvdata(sdev, hub);
-
-	status = ssam_device_notifier_register(sdev, &hub->notif);
-	if (status)
-		return status;
-
-	status = sysfs_create_group(&sdev->dev.kobj, &ssam_base_hub_group);
-	if (status)
-		goto err;
-
-	schedule_delayed_work(&hub->update_work, 0);
-	return 0;
+	hub->connect_delay = SSAM_BASE_UPDATE_CONNECT_DELAY;
+	hub->get_state = ssam_base_hub_query_state;
 
-err:
-	ssam_device_notifier_unregister(sdev, &hub->notif);
-	cancel_delayed_work_sync(&hub->update_work);
-	ssam_remove_clients(&sdev->dev);
-	return status;
-}
-
-static void ssam_base_hub_remove(struct ssam_device *sdev)
-{
-	struct ssam_base_hub *hub = ssam_device_get_drvdata(sdev);
-
-	sysfs_remove_group(&sdev->dev.kobj, &ssam_base_hub_group);
-
-	ssam_device_notifier_unregister(sdev, &hub->notif);
-	cancel_delayed_work_sync(&hub->update_work);
-	ssam_remove_clients(&sdev->dev);
+	return ssam_hub_setup(sdev, hub);
 }
 
 static const struct ssam_device_id ssam_base_hub_match[] = {
@@ -504,12 +541,12 @@ static const struct ssam_device_id ssam_base_hub_match[] = {
 
 static struct ssam_device_driver ssam_base_hub_driver = {
 	.probe = ssam_base_hub_probe,
-	.remove = ssam_base_hub_remove,
+	.remove = ssam_hub_remove,
 	.match_table = ssam_base_hub_match,
 	.driver = {
 		.name = "surface_aggregator_base_hub",
 		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
-		.pm = &ssam_base_hub_pm_ops,
+		.pm = &ssam_hub_pm_ops,
 	},
 };