linux-kernel - [PATCH v3 09/14] remoteproc: Deal with synchronisation when crashing

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Message-Id: <20200424200135.28825-10-mathieu.poirier@linaro.org>
Date:   Fri, 24 Apr 2020 14:01:30 -0600
From:   Mathieu Poirier <mathieu.poirier@...aro.org>
To:     bjorn.andersson@...aro.org, ohad@...ery.com
Cc:     loic.pallardy@...com, arnaud.pouliquen@...com, s-anna@...com,
        linux-remoteproc@...r.kernel.org, corbet@....net,
        linux-doc@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH v3 09/14] remoteproc: Deal with synchronisation when crashing

Refactor function rproc_trigger_recovery() in order to avoid
reloading the firmware image when synchronising with a remote
processor rather than booting it.  Also part of the process,
properly set the synchronisation flag in order to properly
recover the system.

Signed-off-by: Mathieu Poirier <mathieu.poirier@...aro.org>
---
 drivers/remoteproc/remoteproc_core.c     | 23 ++++++++++++++------
 drivers/remoteproc/remoteproc_internal.h | 27 ++++++++++++++++++++++++
 2 files changed, 43 insertions(+), 7 deletions(-)

diff --git a/drivers/remoteproc/remoteproc_core.c b/drivers/remoteproc/remoteproc_core.c
index ef88d3e84bfb..3a84a38ba37b 100644
--- a/drivers/remoteproc/remoteproc_core.c
+++ b/drivers/remoteproc/remoteproc_core.c
@@ -1697,7 +1697,7 @@ static void rproc_coredump(struct rproc *rproc)
  */
 int rproc_trigger_recovery(struct rproc *rproc)
 {
-	const struct firmware *firmware_p;
+	const struct firmware *firmware_p = NULL;
 	struct device *dev = &rproc->dev;
 	int ret;
 
@@ -1718,14 +1718,16 @@ int rproc_trigger_recovery(struct rproc *rproc)
 	/* generate coredump */
 	rproc_coredump(rproc);
 
-	/* load firmware */
-	ret = request_firmware(&firmware_p, rproc->firmware, dev);
-	if (ret < 0) {
-		dev_err(dev, "request_firmware failed: %d\n", ret);
-		goto unlock_mutex;
+	/* load firmware if need be */
+	if (!rproc_needs_syncing(rproc)) {
+		ret = request_firmware(&firmware_p, rproc->firmware, dev);
+		if (ret < 0) {
+			dev_err(dev, "request_firmware failed: %d\n", ret);
+			goto unlock_mutex;
+		}
 	}
 
-	/* boot the remote processor up again */
+	/* boot up or synchronise with the remote processor again */
 	ret = rproc_start(rproc, firmware_p);
 
 	release_firmware(firmware_p);
@@ -1761,6 +1763,13 @@ static void rproc_crash_handler_work(struct work_struct *work)
 	dev_err(dev, "handling crash #%u in %s\n", ++rproc->crash_cnt,
 		rproc->name);
 
+	/*
+	 * The remote processor has crashed - tell the core what operation
+	 * to use from hereon, i.e whether an external entity will reboot
+	 * the MCU or it is now the remoteproc core's responsability.
+	 */
+	rproc_set_sync_flag(rproc, RPROC_SYNC_STATE_CRASHED);
+
 	mutex_unlock(&rproc->lock);
 
 	if (!rproc->recovery_disabled)
diff --git a/drivers/remoteproc/remoteproc_internal.h b/drivers/remoteproc/remoteproc_internal.h
index 3985c084b184..61500981155c 100644
--- a/drivers/remoteproc/remoteproc_internal.h
+++ b/drivers/remoteproc/remoteproc_internal.h
@@ -24,6 +24,33 @@ struct rproc_debug_trace {
 	struct rproc_mem_entry trace_mem;
 };
 
+/*
+ * enum rproc_sync_states - remote processsor sync states
+ *
+ * @RPROC_SYNC_STATE_CRASHED	state to use after the remote processor
+ *				has crashed but has not been recovered by
+ *				the remoteproc core yet.
+ *
+ * Keeping these separate from the enum rproc_state in order to avoid
+ * introducing coupling between the state of the MCU and the synchronisation
+ * operation to use.
+ */
+enum rproc_sync_states {
+	RPROC_SYNC_STATE_CRASHED,
+};
+
+static inline void rproc_set_sync_flag(struct rproc *rproc,
+				       enum rproc_sync_states state)
+{
+	switch (state) {
+	case RPROC_SYNC_STATE_CRASHED:
+		rproc->sync_with_rproc = rproc->sync_flags.after_crash;
+		break;
+	default:
+		break;
+	}
+}
+
 /* from remoteproc_core.c */
 void rproc_release(struct kref *kref);
 irqreturn_t rproc_vq_interrupt(struct rproc *rproc, int vq_id);
-- 
2.20.1