[PATCH 1/2] ASoC: qcom: q6apm: Guard callbacks until probe data is ready

[Mohit Sharma <mohit.sharma@oss.qualcomm.com>]

The GPR bus needs to make response callbacks available before invoking a
client probe because clients can issue synchronous commands from probe.
This creates a short interval where a callback can run before the client
has published its private data.

Make q6apm publish its driver data only after all callback-visible state
has been initialized. Have the q6apm and q6prm callbacks ignore packets
received before driver data is available.

Fixes: ec1471a898cc ("soc: qcom: apr: Add GPR support")
Cc: stable@vger.kernel.org
Co-developed-by: Ajay Kumar Nandam <ajay.nandam@oss.qualcomm.com>
Signed-off-by: Ajay Kumar Nandam <ajay.nandam@oss.qualcomm.com>
Signed-off-by: Mohit Sharma <mohit.sharma@oss.qualcomm.com>
---
 sound/soc/qcom/qdsp6/q6apm.c | 6 ++++--
 sound/soc/qcom/qdsp6/q6prm.c | 3 +++
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/sound/soc/qcom/qdsp6/q6apm.c b/sound/soc/qcom/qdsp6/q6apm.c
index 3ec3c5a18c7a..dbebb643cd5e 100644
--- a/sound/soc/qcom/qdsp6/q6apm.c
+++ b/sound/soc/qcom/qdsp6/q6apm.c
@@ -872,8 +872,6 @@ static int apm_probe(gpr_device_t *gdev)
 	if (!apm)
 		return -ENOMEM;
 
-	dev_set_drvdata(dev, apm);
-
 	mutex_init(&apm->lock);
 	apm->dev = dev;
 	apm->gdev = gdev;
@@ -887,6 +885,7 @@ static int apm_probe(gpr_device_t *gdev)
 
 	idr_init(&apm->modules_idr);
 
+	dev_set_drvdata(dev, apm);
 	g_apm = apm;
 
 	q6apm_get_apm_state(apm);
@@ -930,6 +929,9 @@ static int apm_callback(const struct gpr_resp_pkt *data, void *priv, int op)
 	const struct gpr_hdr *hdr = &data->hdr;
 	int graph_id, is_pos_buf;
 
+	if (!apm)
+		return 0;
+
 	result = data->payload;
 
 	switch (hdr->opcode) {
diff --git a/sound/soc/qcom/qdsp6/q6prm.c b/sound/soc/qcom/qdsp6/q6prm.c
index 2042ff1e8ff1..5c927ebd81f4 100644
--- a/sound/soc/qcom/qdsp6/q6prm.c
+++ b/sound/soc/qcom/qdsp6/q6prm.c
@@ -194,6 +194,9 @@ static int prm_callback(const struct gpr_resp_pkt *data, void *priv, int op)
 	const struct gpr_ibasic_rsp_result_t *result;
 	const struct gpr_hdr *hdr = &data->hdr;
 
+	if (!prm)
+		return 0;
+
 	switch (hdr->opcode) {
 	case PRM_CMD_RSP_REQUEST_HW_RSC:
 	case PRM_CMD_RSP_RELEASE_HW_RSC:
-- 
2.34.1