media: venus: Add support for static video encoder/decoder declarations

Add resource structure data and probe() logic to support static
declarations of encoder and decoder.

Right now we rely on video encoder/decoder selection happening in the dtb
but, this goes against the remit of device tree which is supposed to
describe hardware, not select functional logic in Linux drivers.

Provide two strings in the venus resource structure enc_nodename and
dec_nodename.

When set the venus driver will create an OF entry in-memory consistent
with:

dec_nodename {
    compat = "video-decoder";
};

and/or

enc_nodename {
    compat = "video-encoder";
};

This will allow us to reuse the existing driver scheme of relying on compat
names maintaining compatibility with old dtb files.

dec_nodename can be "video-decoder" or "video0"
enc_nodename can be "video-encoder" or "video1"

This change relies on of_changeset() API as a result select OF_DYNAMIC will
be added to venus/Kconfig

Tested-by: Renjiang Han <quic_renjiang@quicinc.com>
Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Signed-off-by: Stanimir Varbanov <stanimir.k.varbanov@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>

Author: 0xB0D

drivers/media/platform/qcom/venus/Kconfig

@@ -3,6 +3,7 @@ config VIDEO_QCOM_VENUS
 	depends on V4L_MEM2MEM_DRIVERS
 	depends on VIDEO_DEV && QCOM_SMEM
 	depends on (ARCH_QCOM && IOMMU_DMA) || COMPILE_TEST
+	select OF_DYNAMIC if ARCH_QCOM
 	select QCOM_MDT_LOADER if ARCH_QCOM
 	select QCOM_SCM
 	select VIDEOBUF2_DMA_CONTIG

drivers/media/platform/qcom/venus/core.c

@@ -286,6 +286,89 @@ static irqreturn_t venus_isr_thread(int irq, void *dev_id)
 	return ret;
 }
 
+#if defined(CONFIG_OF_DYNAMIC)
+static int venus_add_video_core(struct venus_core *core, const char *node_name,
+				const char *compat)
+{
+	struct of_changeset *ocs = core->ocs;
+	struct device *dev = core->dev;
+	struct device_node *np, *enp;
+	int ret;
+
+	if (!node_name)
+		return 0;
+
+	enp = of_find_node_by_name(dev->of_node, node_name);
+	if (enp) {
+		of_node_put(enp);
+		return 0;
+	}
+
+	np = of_changeset_create_node(ocs, dev->of_node, node_name);
+	if (!np) {
+		dev_err(dev, "Unable to create new node\n");
+		return -ENODEV;
+	}
+
+	ret = of_changeset_add_prop_string(ocs, np, "compatible", compat);
+	if (ret)
+		dev_err(dev, "unable to add %s\n", compat);
+
+	of_node_put(np);
+
+	return ret;
+}
+
+static int venus_add_dynamic_nodes(struct venus_core *core)
+{
+	struct device *dev = core->dev;
+	int ret;
+
+	core->ocs = kmalloc(sizeof(*core->ocs), GFP_KERNEL);
+	if (!core->ocs)
+		return -ENOMEM;
+
+	of_changeset_init(core->ocs);
+
+	ret = venus_add_video_core(core, core->res->dec_nodename, "venus-decoder");
+	if (ret)
+		goto err;
+
+	ret = venus_add_video_core(core, core->res->enc_nodename, "venus-encoder");
+	if (ret)
+		goto err;
+
+	ret = of_changeset_apply(core->ocs);
+	if (ret) {
+		dev_err(dev, "applying changeset fail ret %d\n", ret);
+		goto err;
+	}
+
+	return 0;
+err:
+	of_changeset_destroy(core->ocs);
+	kfree(core->ocs);
+	core->ocs = NULL;
+	return ret;
+}
+
+static void venus_remove_dynamic_nodes(struct venus_core *core)
+{
+	if (core->ocs) {
+		of_changeset_revert(core->ocs);
+		of_changeset_destroy(core->ocs);
+		kfree(core->ocs);
+	}
+}
+#else
+static int venus_add_dynamic_nodes(struct venus_core *core)
+{
+	return 0;
+}
+
+static void venus_remove_dynamic_nodes(struct venus_core *core) {}
+#endif
+
 static int venus_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
@@ -365,9 +448,15 @@ static int venus_probe(struct platform_device *pdev)
 	if (ret < 0)
 		goto err_runtime_disable;
 
+	if (core->res->dec_nodename || core->res->enc_nodename) {
+		ret = venus_add_dynamic_nodes(core);
+		if (ret)
+			goto err_runtime_disable;
+	}
+
 	ret = of_platform_populate(dev->of_node, NULL, NULL, dev);
 	if (ret)
-		goto err_runtime_disable;
+		goto err_remove_dynamic_nodes;
 
 	ret = venus_firmware_init(core);
 	if (ret)
@@ -411,6 +500,8 @@ static int venus_probe(struct platform_device *pdev)
 	venus_firmware_deinit(core);
 err_of_depopulate:
 	of_platform_depopulate(dev);
+err_remove_dynamic_nodes:
+	venus_remove_dynamic_nodes(core);
 err_runtime_disable:
 	pm_runtime_put_noidle(dev);
 	pm_runtime_disable(dev);
@@ -443,6 +534,8 @@ static void venus_remove(struct platform_device *pdev)
 
 	venus_firmware_deinit(core);
 
+	venus_remove_dynamic_nodes(core);
+
 	pm_runtime_put_sync(dev);
 	pm_runtime_disable(dev);
 

drivers/media/platform/qcom/venus/core.h

@@ -90,6 +90,8 @@ struct venus_resources {
 	u32 cp_nonpixel_start;
 	u32 cp_nonpixel_size;
 	const char *fwname;
+	const char *enc_nodename;
+	const char *dec_nodename;
 };
 
 enum venus_fmt {
@@ -169,6 +171,7 @@ struct venus_format {
  * @root:	debugfs root directory
  * @venus_ver:	the venus firmware version
  * @dump_core:	a flag indicating that a core dump is required
+ * @ocs:	OF changeset pointer
  */
 struct venus_core {
 	void __iomem *base;
@@ -231,6 +234,7 @@ struct venus_core {
 		u32 rev;
 	} venus_ver;
 	unsigned long dump_core;
+	struct of_changeset *ocs;
 };
 
 struct vdec_controls {