Re: [PATCH v3 4/7] media: iris: add context bank devices using iommu-map

[Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>]

On Fri, Mar 13, 2026 at 06:49:38PM +0530, Vikash Garodia wrote:
> Introduce different context banks(CB) and the associated buffer region.
> Different stream IDs from VPU would be associated to one of these CB.
> Multiple CBs are needed to increase the IOVA for the video usecases like
> higher concurrent sessions.
> 
> Co-developed-by: Vishnu Reddy <busanna.reddy@oss.qualcomm.com>
> Signed-off-by: Vishnu Reddy <busanna.reddy@oss.qualcomm.com>
> Signed-off-by: Vikash Garodia <vikash.garodia@oss.qualcomm.com>
> ---
>  drivers/media/platform/qcom/iris/iris_core.h       |  2 +
>  .../platform/qcom/iris/iris_platform_common.h      | 14 +++++
>  drivers/media/platform/qcom/iris/iris_probe.c      | 66 ++++++++++++++++++++--
>  drivers/media/platform/qcom/iris/iris_resources.c  | 46 +++++++++++++++
>  drivers/media/platform/qcom/iris/iris_resources.h  |  1 +
>  5 files changed, 125 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/media/platform/qcom/iris/iris_core.h b/drivers/media/platform/qcom/iris/iris_core.h
> index fb194c967ad4f9b5e00cd74f0d41e0b827ef14db..62364bd6909e9a03d223bac86962dc9094a40243 100644
> --- a/drivers/media/platform/qcom/iris/iris_core.h
> +++ b/drivers/media/platform/qcom/iris/iris_core.h
> @@ -34,6 +34,7 @@ enum domain_type {
>   * struct iris_core - holds core parameters valid for all instances
>   *
>   * @dev: reference to device structure
> + * @cb_devs: array of context bank devices (eg: bitstream, non-pixel, pixel, etc)
>   * @reg_base: IO memory base address
>   * @irq: iris irq
>   * @v4l2_dev: a holder for v4l2 device structure
> @@ -77,6 +78,7 @@ enum domain_type {
>  
>  struct iris_core {
>  	struct device				*dev;
> +	struct device				*cb_devs[IRIS_MAX_REGION];
>  	void __iomem				*reg_base;
>  	int					irq;
>  	struct v4l2_device			v4l2_dev;
> diff --git a/drivers/media/platform/qcom/iris/iris_platform_common.h b/drivers/media/platform/qcom/iris/iris_platform_common.h
> index 2273243d1a80446233dd82dcd77444aa043ad064..df63a06b8401cd367c69ab8909af227f04bf69bf 100644
> --- a/drivers/media/platform/qcom/iris/iris_platform_common.h
> +++ b/drivers/media/platform/qcom/iris/iris_platform_common.h
> @@ -204,6 +204,18 @@ struct icc_vote_data {
>  	u32 fps;
>  };
>  
> +enum iris_buffer_region {
> +	IRIS_UNKNOWN_REGION,
> +	IRIS_BITSTREAM_REGION,
> +	IRIS_NON_PIXEL_REGION,
> +	IRIS_PIXEL_REGION,
> +	IRIS_SECURE_BITSTREAM_REGION,
> +	IRIS_SECURE_NON_PIXEL_REGION,
> +	IRIS_SECURE_PIXEL_REGION,
> +	IRIS_FIRMWARE_REGION,
> +	IRIS_MAX_REGION,

Why do you need this enum in addition to the DT bindings? Where are the
bindings being used?

> +};
> +
>  struct iris_context_bank {
>  	char *name;
>  	u32 f_id;
> @@ -252,6 +264,8 @@ struct iris_platform_data {
>  	u32 inst_fw_caps_enc_size;
>  	const struct tz_cp_config *tz_cp_config_data;
>  	u32 tz_cp_config_data_size;
> +	const struct iris_context_bank *cb_data;
> +	const u32 cb_data_size;
>  	u32 core_arch;
>  	u32 hw_response_timeout;
>  	struct ubwc_config_data *ubwc_config;
> diff --git a/drivers/media/platform/qcom/iris/iris_probe.c b/drivers/media/platform/qcom/iris/iris_probe.c
> index ddaacda523ecb9990af0dd0640196223fbcc2cab..439e6e0fe8adf8287f81d26257ef2a7e9f21e53d 100644
> --- a/drivers/media/platform/qcom/iris/iris_probe.c
> +++ b/drivers/media/platform/qcom/iris/iris_probe.c
> @@ -123,6 +123,55 @@ static int iris_init_resets(struct iris_core *core)
>  				     core->iris_platform_data->controller_rst_tbl_size);
>  }
>  
> +static void iris_destroy_child_device(struct iris_core *core, const struct iris_context_bank *cb)
> +{
> +	u32 index, region_mask = cb->region_mask;
> +	struct device *dev = NULL;
> +
> +	while (region_mask) {
> +		index = __ffs(region_mask);
> +		dev = core->cb_devs[index];
> +		core->cb_devs[index] = NULL;
> +		region_mask &= ~BIT(index);
> +	}
> +
> +	if (dev)
> +		device_unregister(dev);

Which devices will be unregistered? You are setting dev in a loop, which
means that only the last one will be unregistered (and only if it is not
NULL).

> +}
> +
> +static void iris_deinit_context_bank_devices(struct iris_core *core)
> +{
> +	const struct iris_context_bank *cb;
> +	int i;
> +
> +	for (i = 0; i < core->iris_platform_data->cb_data_size; i++) {
> +		cb = &core->iris_platform_data->cb_data[i];
> +		iris_destroy_child_device(core, cb);
> +	}
> +}
> +
> +static int iris_init_context_bank_devices(struct iris_core *core)
> +{
> +	const struct iris_context_bank *cb;
> +	int ret, i;
> +
> +	for (i = 0; i < core->iris_platform_data->cb_data_size; i++) {
> +		cb = &core->iris_platform_data->cb_data[i];
> +
> +		ret = iris_create_child_device_and_map(core, cb);
> +		if (ret)
> +			goto err_deinit_cb;
> +	}
> +
> +	return 0;
> +
> +err_deinit_cb:
> +	while (i-- > 0)
> +		iris_destroy_child_device(core, &core->iris_platform_data->cb_data[i]);
> +
> +	return ret;
> +}
> +
>  static int iris_init_resources(struct iris_core *core)
>  {
>  	int ret;
> @@ -193,6 +242,7 @@ static void iris_remove(struct platform_device *pdev)
>  		return;
>  
>  	iris_core_deinit(core);
> +	iris_deinit_context_bank_devices(core);
>  
>  	video_unregister_device(core->vdev_dec);
>  	video_unregister_device(core->vdev_enc);
> @@ -275,12 +325,18 @@ static int iris_probe(struct platform_device *pdev)
>  
>  	platform_set_drvdata(pdev, core);
>  
> -	dma_mask = core->iris_platform_data->dma_mask;
> -
> -	ret = dma_set_mask_and_coherent(dev, dma_mask);
> +	ret = iris_init_context_bank_devices(core);
>  	if (ret)
>  		goto err_vdev_unreg_enc;
>  
> +	dma_mask = core->iris_platform_data->dma_mask;
> +
> +	if (device_iommu_mapped(core->dev)) {
> +		ret = dma_set_mask_and_coherent(core->dev, dma_mask);
> +		if (ret)
> +			goto err_deinit_cb;
> +	}
> +
>  	dma_set_max_seg_size(&pdev->dev, DMA_BIT_MASK(32));
>  	dma_set_seg_boundary(&pdev->dev, DMA_BIT_MASK(32));
>  
> @@ -288,10 +344,12 @@ static int iris_probe(struct platform_device *pdev)
>  	pm_runtime_use_autosuspend(core->dev);
>  	ret = devm_pm_runtime_enable(core->dev);
>  	if (ret)
> -		goto err_vdev_unreg_enc;
> +		goto err_deinit_cb;
>  
>  	return 0;
>  
> +err_deinit_cb:
> +	iris_deinit_context_bank_devices(core);
>  err_vdev_unreg_enc:
>  	video_unregister_device(core->vdev_enc);
>  err_vdev_unreg_dec:
> diff --git a/drivers/media/platform/qcom/iris/iris_resources.c b/drivers/media/platform/qcom/iris/iris_resources.c
> index 773f6548370a257b8ae7332242544266cbbd61a9..a2e648f4cdb8c63db89396d49f32bbc06d870ea5 100644
> --- a/drivers/media/platform/qcom/iris/iris_resources.c
> +++ b/drivers/media/platform/qcom/iris/iris_resources.c
> @@ -6,6 +6,7 @@
>  #include <linux/clk.h>
>  #include <linux/devfreq.h>
>  #include <linux/interconnect.h>
> +#include <linux/iris_vpu_bus.h>
>  #include <linux/pm_domain.h>
>  #include <linux/pm_opp.h>
>  #include <linux/pm_runtime.h>
> @@ -141,3 +142,48 @@ int iris_disable_unprepare_clock(struct iris_core *core, enum platform_clk_type
>  
>  	return 0;
>  }
> +
> +static void iris_device_release(struct device *dev)
> +{
> +	dev_set_drvdata(dev, NULL);

There is no need to clean this pointer.

> +	kfree(dev);
> +}
> +
> +int iris_create_child_device_and_map(struct iris_core *core, const struct iris_context_bank *cb)
> +{
> +	u32 index, region_mask = cb->region_mask;
> +	struct device *dev;
> +	int ret;
> +
> +	dev = kzalloc_obj(*dev);
> +	if (!dev)
> +		return -ENOMEM;
> +
> +	dev->release = iris_device_release;
> +	dev->bus = &iris_vpu_bus_type;
> +	dev->parent = core->dev;
> +	dev->coherent_dma_mask = core->iris_platform_data->dma_mask;
> +	dev->dma_mask = &dev->coherent_dma_mask;
> +
> +	dev_set_name(dev, "%s", cb->name);
> +	dev_set_drvdata(dev, (void *)cb);
> +
> +	ret = device_register(dev);
> +	if (ret) {
> +		put_device(dev);
> +		return ret;
> +	}
> +
> +	if (!device_iommu_mapped(dev)) {
> +		device_unregister(dev);
> +		return 0;
> +	}
> +
> +	while (region_mask) {
> +		index = __ffs(region_mask);
> +		core->cb_devs[index] = dev;

This needs to have some explanation how region masks work with the
device types.

> +		region_mask &= ~BIT(index);
> +	}
> +
> +	return 0;
> +}
> diff --git a/drivers/media/platform/qcom/iris/iris_resources.h b/drivers/media/platform/qcom/iris/iris_resources.h
> index 6bfbd2dc6db095ec05e53c894e048285f82446c6..c573016535b87d4fd140cad967d926cc1de63382 100644
> --- a/drivers/media/platform/qcom/iris/iris_resources.h
> +++ b/drivers/media/platform/qcom/iris/iris_resources.h
> @@ -15,5 +15,6 @@ int iris_unset_icc_bw(struct iris_core *core);
>  int iris_set_icc_bw(struct iris_core *core, unsigned long icc_bw);
>  int iris_disable_unprepare_clock(struct iris_core *core, enum platform_clk_type clk_type);
>  int iris_prepare_enable_clock(struct iris_core *core, enum platform_clk_type clk_type);
> +int iris_create_child_device_and_map(struct iris_core *core, const struct iris_context_bank *cb);
>  
>  #endif
> 
> -- 
> 2.34.1
> 

-- 
With best wishes
Dmitry