[PATCH v2 2/4] venus: Limit HFI sessions to the maximum supported

[Stanimir Varbanov <stanimir.varbanov@xxxxxxxxxx>]

Currently we rely on firmware to return error when we reach the maximum
supported number of sessions. But this errors are happened at reqbuf
time which is a bit later. The more reasonable way looks like is to
return the error on driver open.

To achieve that modify hfi_session_create to return error when we reach
maximum count of sessions and thus refuse open.

Signed-off-by: Stanimir Varbanov <stanimir.varbanov@xxxxxxxxxx>
---
 drivers/media/platform/qcom/venus/core.h       |  1 +
 drivers/media/platform/qcom/venus/hfi.c        | 16 +++++++++++++---
 drivers/media/platform/qcom/venus/hfi_parser.c |  3 +++
 3 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/drivers/media/platform/qcom/venus/core.h b/drivers/media/platform/qcom/venus/core.h
index f03ed427accd..775d7bf6587d 100644
--- a/drivers/media/platform/qcom/venus/core.h
+++ b/drivers/media/platform/qcom/venus/core.h
@@ -96,6 +96,7 @@ struct venus_format {
 #define MAX_CAP_ENTRIES		32
 #define MAX_ALLOC_MODE_ENTRIES	16
 #define MAX_CODEC_NUM		32
+#define MAX_SESSIONS		16
 
 struct raw_formats {
 	u32 buftype;
diff --git a/drivers/media/platform/qcom/venus/hfi.c b/drivers/media/platform/qcom/venus/hfi.c
index 638ed5cfe05e..8786609d269e 100644
--- a/drivers/media/platform/qcom/venus/hfi.c
+++ b/drivers/media/platform/qcom/venus/hfi.c
@@ -175,6 +175,8 @@ static int wait_session_msg(struct venus_inst *inst)
 int hfi_session_create(struct venus_inst *inst, const struct hfi_inst_ops *ops)
 {
 	struct venus_core *core = inst->core;
+	bool max;
+	int ret;
 
 	if (!ops)
 		return -EINVAL;
@@ -184,11 +186,19 @@ int hfi_session_create(struct venus_inst *inst, const struct hfi_inst_ops *ops)
 	inst->ops = ops;
 
 	mutex_lock(&core->lock);
-	list_add_tail(&inst->list, &core->instances);
-	atomic_inc(&core->insts_count);
+
+	max = atomic_add_unless(&core->insts_count, 1,
+				core->max_sessions_supported);
+	if (!max) {
+		ret = -EAGAIN;
+	} else {
+		list_add_tail(&inst->list, &core->instances);
+		ret = 0;
+	}
+
 	mutex_unlock(&core->lock);
 
-	return 0;
+	return ret;
 }
 EXPORT_SYMBOL_GPL(hfi_session_create);
 
diff --git a/drivers/media/platform/qcom/venus/hfi_parser.c b/drivers/media/platform/qcom/venus/hfi_parser.c
index 363ee2a65453..52898633a8e6 100644
--- a/drivers/media/platform/qcom/venus/hfi_parser.c
+++ b/drivers/media/platform/qcom/venus/hfi_parser.c
@@ -276,6 +276,9 @@ u32 hfi_parser(struct venus_core *core, struct venus_inst *inst, void *buf,
 		words_count--;
 	}
 
+	if (!core->max_sessions_supported)
+		core->max_sessions_supported = MAX_SESSIONS;
+
 	parser_fini(inst, codecs, domain);
 
 	return HFI_ERR_NONE;
-- 
2.17.1