remoteproc: qcom: Add notification types to SSR

The SSR subdevice only adds callback for the unprepare event. Add callbacks
for prepare, start and prepare events. The client driver for a particular
remoteproc might be interested in knowing the status of the remoteproc
while undergoing SSR, not just when the remoteproc has finished shutting
down.
Reviewed-by: Alex Elder <elder@linaro.org>
Signed-off-by: Siddharth Gupta <sidgup@codeaurora.org>
Signed-off-by: Rishabh Bhatnagar <rishabhb@codeaurora.org>
Link: https://lore.kernel.org/r/1592965408-16908-3-git-send-email-rishabhb@codeaurora.orgSigned-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

drivers/remoteproc/qcom_common.c

@@ -265,6 +265,44 @@ int qcom_unregister_ssr_notifier(void *notify, struct notifier_block *nb)
 }
 EXPORT_SYMBOL_GPL(qcom_unregister_ssr_notifier);
 
+static int ssr_notify_prepare(struct rproc_subdev *subdev)
+{
+	struct qcom_rproc_ssr *ssr = to_ssr_subdev(subdev);
+	struct qcom_ssr_notify_data data = {
+		.name = ssr->info->name,
+		.crashed = false,
+	};
+
+	srcu_notifier_call_chain(&ssr->info->notifier_list,
+				 QCOM_SSR_BEFORE_POWERUP, &data);
+	return 0;
+}
+
+static int ssr_notify_start(struct rproc_subdev *subdev)
+{
+	struct qcom_rproc_ssr *ssr = to_ssr_subdev(subdev);
+	struct qcom_ssr_notify_data data = {
+		.name = ssr->info->name,
+		.crashed = false,
+	};
+
+	srcu_notifier_call_chain(&ssr->info->notifier_list,
+				 QCOM_SSR_AFTER_POWERUP, &data);
+	return 0;
+}
+
+static void ssr_notify_stop(struct rproc_subdev *subdev, bool crashed)
+{
+	struct qcom_rproc_ssr *ssr = to_ssr_subdev(subdev);
+	struct qcom_ssr_notify_data data = {
+		.name = ssr->info->name,
+		.crashed = crashed,
+	};
+
+	srcu_notifier_call_chain(&ssr->info->notifier_list,
+				 QCOM_SSR_BEFORE_SHUTDOWN, &data);
+}
+
 static void ssr_notify_unprepare(struct rproc_subdev *subdev)
 {
 	struct qcom_rproc_ssr *ssr = to_ssr_subdev(subdev);
@@ -273,7 +311,8 @@ static void ssr_notify_unprepare(struct rproc_subdev *subdev)
 		.crashed = false,
 	};
 
-	srcu_notifier_call_chain(&ssr->info->notifier_list, 0, &data);
+	srcu_notifier_call_chain(&ssr->info->notifier_list,
+				 QCOM_SSR_AFTER_SHUTDOWN, &data);
 }
 
 /**
@@ -298,6 +337,9 @@ void qcom_add_ssr_subdev(struct rproc *rproc, struct qcom_rproc_ssr *ssr,
 	}
 
 	ssr->info = info;
+	ssr->subdev.prepare = ssr_notify_prepare;
+	ssr->subdev.start = ssr_notify_start;
+	ssr->subdev.stop = ssr_notify_stop;
 	ssr->subdev.unprepare = ssr_notify_unprepare;
 
 	rproc_add_subdev(rproc, &ssr->subdev);

include/linux/remoteproc/qcom_rproc.h

@@ -5,6 +5,22 @@ struct notifier_block;
 
 #if IS_ENABLED(CONFIG_QCOM_RPROC_COMMON)
 
+/**
+ * enum qcom_ssr_notify_type - Startup/Shutdown events related to a remoteproc
+ * processor.
+ *
+ * @QCOM_SSR_BEFORE_POWERUP:	Remoteproc about to start (prepare stage)
+ * @QCOM_SSR_AFTER_POWERUP:	Remoteproc is running (start stage)
+ * @QCOM_SSR_BEFORE_SHUTDOWN:	Remoteproc crashed or shutting down (stop stage)
+ * @QCOM_SSR_AFTER_SHUTDOWN:	Remoteproc is down (unprepare stage)
+ */
+enum qcom_ssr_notify_type {
+	QCOM_SSR_BEFORE_POWERUP,
+	QCOM_SSR_AFTER_POWERUP,
+	QCOM_SSR_BEFORE_SHUTDOWN,
+	QCOM_SSR_AFTER_SHUTDOWN,
+};
+
 struct qcom_ssr_notify_data {
 	const char *name;
 	bool crashed;