[PATCH v6 04/12] media: iris: Add non-pixel and pixel context bank devices

[Vikash Garodia]

The VPU issues DMA through several SMMU streams, and the hardware does
not give every stream the same addressable range. The non-pixel stream
cannot address the low 600MB of IOVA space, while the pixel stream can
address the full range:
    +-----------------------------------------------------------+
    | non-pixel stream addressable range (600 MB - 3.5 GB)      |
    | 0x25800000 - 0xe0000000                                   |
    +-----------------------------------------------------------+
    | pixel stream addressable range (0 - 3.5 GB)               |
    | 0x00000000 - 0xe0000000                                   |
    +-----------------------------------------------------------+
A single "iommus" property on the video-codec node puts every stream in
one IOMMU domain sharing one IOVA allocator, so nothing restricts a
non-pixel buffer to avoid 0 to 600MB. Once an allocation lands below
that boundary the hardware faults, which shows up as unhandled SMMU page
faults and spontaneous reboots:
https://gitlab.freedesktop.org/drm/msm/-/work_items/100

Now the device tree describes "non-pixel" and "pixel" as separate
context bank subnodes, each carrying its own "iommus" stream IDs.

Add helper functions to create and clean up devices from these DT
subnodes, and call them from iris_probe() and iris_remove(). This
applies to the common probe path as it is required for all platforms.

Set the context banks before v4l2_device_register() so the DMA plumbing
is in place before any video device is visible to userspace, and tear
them down on the probe error path and in iris_remove().

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxxxxxxxx>
Co-developed-by: Vishnu Reddy <busanna.reddy@xxxxxxxxxxxxxxxx>
Signed-off-by: Vishnu Reddy <busanna.reddy@xxxxxxxxxxxxxxxx>
Signed-off-by: Vikash Garodia <vikash.garodia@xxxxxxxxxxxxxxxx>
---
 drivers/media/platform/qcom/iris/iris_core.h  |  4 ++
 drivers/media/platform/qcom/iris/iris_probe.c | 66 +++++++++++++++++++++++++++
 2 files changed, 70 insertions(+)

diff --git a/drivers/media/platform/qcom/iris/iris_core.h b/drivers/media/platform/qcom/iris/iris_core.h
index 3e4cf652bf39a7ef44f5c94ce91d0ba9c109e178..2f14d80d25899244028cad1e6c16e595edcb1493 100644
--- a/drivers/media/platform/qcom/iris/iris_core.h
+++ b/drivers/media/platform/qcom/iris/iris_core.h
@@ -40,6 +40,8 @@ struct qcom_ubwc_cfg_data;
  * struct iris_core - holds core parameters valid for all instances
  *
  * @dev: reference to device structure
+ * @np_dev: reference to non-pixel device structure
+ * @p_dev: reference to pixel device structure
  * @reg_base: IO memory base address
  * @irq: iris irq
  * @v4l2_dev: a holder for v4l2 device structure
@@ -86,6 +88,8 @@ struct qcom_ubwc_cfg_data;
 
 struct iris_core {
 	struct device				*dev;
+	struct device				*np_dev;
+	struct device				*p_dev;
 	void __iomem				*reg_base;
 	int					irq;
 	struct v4l2_device			v4l2_dev;
diff --git a/drivers/media/platform/qcom/iris/iris_probe.c b/drivers/media/platform/qcom/iris/iris_probe.c
index 25876957381b97f7ebf141bc87a7895cacff84b5..e659461716ba46c84d616b41f477b6250d46bd81 100644
--- a/drivers/media/platform/qcom/iris/iris_probe.c
+++ b/drivers/media/platform/qcom/iris/iris_probe.c
@@ -201,6 +201,67 @@ static int iris_reserve_iova_region(struct device *dev, struct dma_iova_state **
 	return ret;
 }
 
+static struct device *iris_create_cb_dev(struct iris_core *core, const char *name)
+{
+	struct platform_device_info plat_dev_info = {};
+	struct device_node *child_of_node;
+	struct platform_device *pdev;
+
+	child_of_node = of_get_child_by_name(core->dev->of_node, name);
+	if (!child_of_node)
+		return NULL;
+
+	plat_dev_info.dma_mask = core->iris_platform_data->dma_mask;
+	plat_dev_info.fwnode = &child_of_node->fwnode;
+	plat_dev_info.name = child_of_node->name;
+	plat_dev_info.id = PLATFORM_DEVID_AUTO;
+	plat_dev_info.parent = core->dev;
+
+	pdev = platform_device_register_full(&plat_dev_info);
+	of_node_put(child_of_node);
+	if (IS_ERR(pdev))
+		return ERR_CAST(pdev);
+
+	dma_set_max_seg_size(&pdev->dev, DMA_BIT_MASK(32));
+	dma_set_seg_boundary(&pdev->dev, DMA_BIT_MASK(32));
+
+	return &pdev->dev;
+}
+
+static int iris_init_cb_devs(struct iris_core *core)
+{
+	struct device *dev;
+
+	dev = iris_create_cb_dev(core, "non-pixel");
+	if (IS_ERR(dev))
+		return PTR_ERR(dev);
+
+	core->np_dev = dev;
+
+	dev = iris_create_cb_dev(core, "pixel");
+	if (IS_ERR(dev))
+		goto unreg_np_dev;
+
+	core->p_dev = dev;
+
+	return 0;
+
+unreg_np_dev:
+	if (core->np_dev)
+		platform_device_unregister(to_platform_device(core->np_dev));
+	core->np_dev = NULL;
+
+	return PTR_ERR(dev);
+}
+
+static void iris_deinit_cb_devs(struct iris_core *core)
+{
+	if (core->p_dev)
+		platform_device_unregister(to_platform_device(core->p_dev));
+	if (core->np_dev)
+		platform_device_unregister(to_platform_device(core->np_dev));
+}
+
 static int iris_register_video_device(struct iris_core *core, enum domain_type type)
 {
 	struct video_device *vdev;
@@ -247,6 +308,7 @@ static void iris_core_release(struct v4l2_device *v4l2_dev)
 {
 	struct iris_core *core = container_of(v4l2_dev, struct iris_core, v4l2_dev);
 
+	iris_deinit_cb_devs(core);
 	mutex_destroy(&core->lock);
 	put_device(core->dev);
 	kfree(core);
@@ -351,6 +413,10 @@ static int iris_probe(struct platform_device *pdev)
 	if (ret)
 		goto err_put_core;
 
+	ret = iris_init_cb_devs(core);
+	if (ret)
+		goto err_put_core;
+
 	ret = v4l2_device_register(dev, &core->v4l2_dev);
 	if (ret)
 		goto err_unresv_iova_region;

-- 
2.34.1