Re: [PATCH 6/7] remoteproc: qcom_q6v5_pas: Add hwspinlock bust on stop

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On 5/17/2024 4:28 AM, Chris Lew wrote:
From: Richard Maina <quic_rmaina@xxxxxxxxxxx>

When remoteproc goes down unexpectedly this results in a state where any
acquired hwspinlocks will remain locked possibly resulting in deadlock.
In order to ensure all locks are freed we include a call to
hwspin_lock_bust() during remoteproc shutdown.

For qcom_q6v5_pas remoteprocs, each remoteproc has an assigned id that
is used to take the hwspinlock. Remoteproc should use this id to try and
bust the lock on remoteproc stop.

This edge case only occurs with q6v5_pas watchdog crashes. The error
fatal case has handling to clear the hwspinlock before the error fatal
interrupt is triggered.

Signed-off-by: Richard Maina <quic_rmaina@xxxxxxxxxxx>
Signed-off-by: Chris Lew <quic_clew@xxxxxxxxxxx>
---
  drivers/remoteproc/qcom_q6v5_pas.c | 28 ++++++++++++++++++++++++++++
  1 file changed, 28 insertions(+)

diff --git a/drivers/remoteproc/qcom_q6v5_pas.c b/drivers/remoteproc/qcom_q6v5_pas.c
index 54d8005d40a3..57178fcb9aa3 100644
--- a/drivers/remoteproc/qcom_q6v5_pas.c
+++ b/drivers/remoteproc/qcom_q6v5_pas.c
@@ -10,6 +10,7 @@
  #include <linux/clk.h>
  #include <linux/delay.h>
  #include <linux/firmware.h>
+#include <linux/hwspinlock.h>
  #include <linux/interrupt.h>
  #include <linux/kernel.h>
  #include <linux/module.h>
@@ -52,6 +53,7 @@ struct adsp_data {
  	const char *ssr_name;
  	const char *sysmon_name;
  	int ssctl_id;
+	int hwlock_id;
int region_assign_idx;
  	int region_assign_count;
@@ -84,6 +86,9 @@ struct qcom_adsp {
  	bool decrypt_shutdown;
  	const char *info_name;
+ struct hwspinlock *hwlock;
+	int hwlock_id;
+
  	const struct firmware *firmware;
  	const struct firmware *dtb_firmware;
@@ -399,6 +404,12 @@ static int adsp_stop(struct rproc *rproc)
  	if (handover)
  		qcom_pas_handover(&adsp->q6v5);
+ if (adsp->hwlock) {
+		ret = hwspin_lock_bust(adsp->hwlock, adsp->hwlock_id);
+		if (ret)
+			dev_info(adsp->dev, "failed to bust hwspinlock\n");
+	}
+

What if recovery is disabled, fatal case is clearing the hwspinlock but
wdog case is not, right ?

-Mukesh




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