[PATCH v2 09/12] remoteproc: stm32: Update M4 state in stm32_rproc_stop()

[Mathieu Poirier]

Update the M4 co-processor state in function stm32_rproc_stop() so
that it can be used in synchronisation scenarios.

Mainly based on the work published by Arnaud Pouliquen [1].

[1]. https://patchwork.kernel.org/project/linux-remoteproc/list/?series=239877

Signed-off-by: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>
---
 drivers/remoteproc/stm32_rproc.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/drivers/remoteproc/stm32_rproc.c b/drivers/remoteproc/stm32_rproc.c
index 404f17a97095..86d23c35d805 100644
--- a/drivers/remoteproc/stm32_rproc.c
+++ b/drivers/remoteproc/stm32_rproc.c
@@ -493,6 +493,18 @@ static int stm32_rproc_stop(struct rproc *rproc)
 		}
 	}
 
+	/* update coprocessor state to OFF if available */
+	if (ddata->m4_state.map) {
+		err = regmap_update_bits(ddata->m4_state.map,
+					 ddata->m4_state.reg,
+					 ddata->m4_state.mask,
+					 M4_STATE_OFF);
+		if (err) {
+			dev_err(&rproc->dev, "failed to set copro state\n");
+			return err;
+		}
+	}
+
 	return 0;
 }
 
@@ -531,6 +543,7 @@ static struct rproc_ops st_rproc_ops = {
 
 static __maybe_unused struct rproc_ops st_rproc_sync_ops = {
 	.start		= stm32_rproc_sync_start,
+	.stop		= stm32_rproc_stop,
 };
 
 static const struct of_device_id stm32_rproc_match[] = {
-- 
2.20.1