[RFC PATCH v10 1/2] media: iris: introduce helper module to select video driver

Dikshita Agarwal
2025-01-28T08:05:33Z

Introduce a helper module with a kernel param to select between
venus and iris drivers for platforms supported by both drivers.

Signed-off-by: Dikshita Agarwal <quic_dikshita@quicinc.com>
---
drivers/media/platform/qcom/Makefile | 1 +
drivers/media/platform/qcom/iris/iris_core.h | 1 +
drivers/media/platform/qcom/iris/iris_probe.c | 3 +
drivers/media/platform/qcom/venus/core.c | 5 ++
.../platform/qcom/video_drv_helper/Makefile | 4 ++
.../qcom/video_drv_helper/video_drv_helper.c | 70 +++++++++++++++++++
.../qcom/video_drv_helper/video_drv_helper.h | 11 +++
7 files changed, 95 insertions(+)
create mode 100644 drivers/media/platform/qcom/video_drv_helper/Makefile
create mode 100644 drivers/media/platform/qcom/video_drv_helper/video_drv_helper.c
create mode 100644 drivers/media/platform/qcom/video_drv_helper/video_drv_helper.h

diff --git a/drivers/media/platform/qcom/Makefile b/drivers/media/platform/qcom/Makefile
index ea2221a202c0..15accde3bd67 100644
--- a/drivers/media/platform/qcom/Makefile
+++ b/drivers/media/platform/qcom/Makefile
@@ -2,3 +2,4 @@
obj-y += camss/
obj-y += iris/
obj-y += venus/
+obj-y += video_drv_helper/
diff --git a/drivers/media/platform/qcom/iris/iris_core.h b/drivers/media/platform/qcom/iris/iris_core.h
index 37fb4919fecc..7108e751ff88 100644
--- a/drivers/media/platform/qcom/iris/iris_core.h
+++ b/drivers/media/platform/qcom/iris/iris_core.h
@@ -107,5 +107,6 @@ struct iris_core {

int iris_core_init(struct iris_core *core);
void iris_core_deinit(struct iris_core *core);
+extern bool video_drv_should_bind(struct device *dev, bool is_iris_driver);

#endif
diff --git a/drivers/media/platform/qcom/iris/iris_probe.c b/drivers/media/platform/qcom/iris/iris_probe.c
index 954cc7c0cc97..276461ade811 100644
--- a/drivers/media/platform/qcom/iris/iris_probe.c
+++ b/drivers/media/platform/qcom/iris/iris_probe.c
@@ -196,6 +196,9 @@ static int iris_probe(struct platform_device *pdev)
u64 dma_mask;
int ret;

+ if (!video_drv_should_bind(&pdev->dev, true))
+ return -ENODEV;
+
core = devm_kzalloc(&pdev->dev, sizeof(*core), GFP_KERNEL);
if (!core)
return -ENOMEM;
diff --git a/drivers/media/platform/qcom/venus/core.c b/drivers/media/platform/qcom/venus/core.c
index 77d48578ecd2..b38be7812efe 100644
--- a/drivers/media/platform/qcom/venus/core.c
+++ b/drivers/media/platform/qcom/venus/core.c
@@ -369,12 +369,17 @@ static int venus_add_dynamic_nodes(struct venus_core *core)
static void venus_remove_dynamic_nodes(struct venus_core *core) {}
#endif

+extern bool video_drv_should_bind(struct device *dev, bool is_iris_driver);
+
static int venus_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct venus_core *core;
int ret;

+ if (!video_drv_should_bind(&pdev->dev, false))
+ return -ENODEV;
+
core = devm_kzalloc(dev, sizeof(*core), GFP_KERNEL);
if (!core)
return -ENOMEM;
diff --git a/drivers/media/platform/qcom/video_drv_helper/Makefile b/drivers/media/platform/qcom/video_drv_helper/Makefile
new file mode 100644
index 000000000000..82567e0392fb
--- /dev/null
+++ b/drivers/media/platform/qcom/video_drv_helper/Makefile
@@ -0,0 +1,4 @@
+# Makefile for Video driver helper
+
+obj-m := video_drv_helper.o
+
diff --git a/drivers/media/platform/qcom/video_drv_helper/video_drv_helper.c b/drivers/media/platform/qcom/video_drv_helper/video_drv_helper.c
new file mode 100644
index 000000000000..9009c2906e54
--- /dev/null
+++ b/drivers/media/platform/qcom/video_drv_helper/video_drv_helper.c
@@ -0,0 +1,70 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2025 Qualcomm Innovation Center, Inc. All rights reserved.
+ */
+
+#include <linux/device.h>
+#include <linux/module.h>
+#include <linux/of.h>
+
+#include "video_drv_helper.h"
+
+/* The venus driver supports only hfi gen1 to communicate with the firmware while
+ * the iris driver supports both hfi gen1 and hfi gen2.
+ * The support of hfi gen1 is added to the iris driver with the intention that
+ * it can support old gen1 interface based firmware, while enabling gen2 based future SOCs.
+ * With this, the plan is to migrate older SOCs from venus to iris.
+ * As of now, since the iris driver supports only entry level features and doesn't have
+ * feature parity with the venus driver, a runtime-selection is provided to user via
+ * module parameter 'prefer_venus' to select the driver.
+ * This selection is available only for the SoCs which are supported by both venus
+ * and iris eg: SM8250.
+ * When the feature parity is achieved, the plan is to switch the default to point to
+ * the iris driver, then gradually start removing platforms from venus.
+ * Hardware supported by only venus - 8916, 8996, SDM660, SDM845, SC7180, SC7280
+ * Hardware supported by only iris - SM8550
+ * Hardware supported by both venus and iris - SM8250
+ */
+
+#if !IS_REACHABLE(CONFIG_VIDEO_QCOM_VENUS) || !IS_REACHABLE(CONFIG_VIDEO_QCOM_IRIS)
+bool video_drv_should_bind(struct device *dev, bool is_iris_driver)
+{
+ /* If just a single driver is enabled, use it no matter what */
+ return true;
+}
+
+#else
+static bool prefer_venus = true;
+MODULE_PARM_DESC(prefer_venus, "Select whether venus or iris driver should be preferred");
+module_param(prefer_venus, bool, 0444);
+
+/* list all platforms supported by both venus and iris drivers */
+static const char *const venus_to_iris_migration[] = {
+ "qcom,sm8250-venus",
+ NULL,
+};
+
+bool video_drv_should_bind(struct device *dev, bool is_iris_driver)
+{
+ if (of_device_compatible_match(dev->of_node, venus_to_iris_migration))
+ return prefer_venus ? !is_iris_driver : is_iris_driver;
+
+ return true;
+}
+EXPORT_SYMBOL_GPL(video_drv_should_bind);
+#endif
+
+static int __init video_drv_helper_init(void)
+{
+ return 0;
+}
+
+static void __exit video_drv_helper_exit(void)
+{
+}
+
+module_init(video_drv_helper_init);
+module_exit(video_drv_helper_exit);
+
+MODULE_DESCRIPTION("A video driver helper module");
+MODULE_LICENSE("GPL");
diff --git a/drivers/media/platform/qcom/video_drv_helper/video_drv_helper.h b/drivers/media/platform/qcom/video_drv_helper/video_drv_helper.h
new file mode 100644
index 000000000000..6d835227fec2
--- /dev/null
+++ b/drivers/media/platform/qcom/video_drv_helper/video_drv_helper.h
@@ -0,0 +1,11 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (c) 2025 Qualcomm Innovation Center, Inc. All rights reserved.
+ */
+
+#ifndef __VIDEO_DRV_HELPER_H__
+#define __VIDEO_DRV_HELPER_H__
+
+bool video_drv_should_bind(struct device *dev, bool is_iris_driver);
+
+#endif
--
2.34.1