Re: [PATCH v4 07/13] media: iris: Enable Secure PAS support with IOMMU managed by Linux

[Vishnu Reddy]

On 5/6/2026 10:51 AM, Mukesh Ojha wrote:
> On Tue, May 05, 2026 at 12:29:28PM +0530, Vishnu Reddy wrote:
>> From: Mukesh Ojha <mukesh.ojha@xxxxxxxxxxxxxxxx>
>>
>> Most Qualcomm platforms feature a proprietary hypervisor (such as Gunyah
>> or QHEE), which typically handles IOMMU configuration. This includes
>> mapping memory regions and device memory resources for remote processors
>> by intercepting qcom_scm_pas_auth_and_reset() calls. These mappings are
>> later removed during teardown. Additionally, SHM bridge setup is required
>> to enable memory protection for both remoteproc metadata and its memory
>> regions.
>>
>> When the hypervisor is absent, the operating system must perform these
>> configurations instead.
>>
>> Support for handling IOMMU and SHM setup in the absence of a hypervisor
>> is now in place. Extend the Iris driver to enable this functionality on
>> platforms where IOMMU is managed by Linux (i.e., non-Gunyah, non-QHEE).
>>
>> Additionally, the Iris driver must map the firmware and its required
>> resources to the firmware SID, which is now specified via iommu-map in
>> the device tree.
>>
>> Co-developed-by: Vikash Garodia <vikash.garodia@xxxxxxxxxxxxxxxx>
>> Signed-off-by: Vikash Garodia <vikash.garodia@xxxxxxxxxxxxxxxx>
>> Signed-off-by: Mukesh Ojha <mukesh.ojha@xxxxxxxxxxxxxxxx>
>> Signed-off-by: Vishnu Reddy <busanna.reddy@xxxxxxxxxxxxxxxx>
> I have posted https://lore.kernel.org/lkml/20260506050107.1985033-1-mukesh.ojha@xxxxxxxxxxxxxxxx/#r
> for resource table extraction and the API to map and unmap and now you
> can use the api similar to below
> https://lore.kernel.org/lkml/20250819165447.4149674-12-mukesh.ojha@xxxxxxxxxxxxxxxx/

Thanks for letting me know, rather than introducing a dependency for this
series, I'd keep them independent for now. If your series lands first, I
can update my patches to use the new API. Otherwise, I'm happy to volunteer
a follow-up patch on top of my series once your patches are merged.

Thanks,
Vishnu Reddy.

>> ---
>>  drivers/media/platform/qcom/iris/iris_core.h     |  4 ++
>>  drivers/media/platform/qcom/iris/iris_firmware.c | 72 ++++++++++++++++++++----
>>  2 files changed, 66 insertions(+), 10 deletions(-)
>>
>> diff --git a/drivers/media/platform/qcom/iris/iris_core.h b/drivers/media/platform/qcom/iris/iris_core.h
>> index fb194c967ad4..b396c8cf595e 100644
>> --- a/drivers/media/platform/qcom/iris/iris_core.h
>> +++ b/drivers/media/platform/qcom/iris/iris_core.h
>> @@ -34,6 +34,8 @@ enum domain_type {
>>   * struct iris_core - holds core parameters valid for all instances
>>   *
>>   * @dev: reference to device structure
>> + * @fw_dev: reference to the context bank device used for firmware load
>> + * @pas_ctx: SCM PAS context for authenticated firmware load and shutdown
>>   * @reg_base: IO memory base address
>>   * @irq: iris irq
>>   * @v4l2_dev: a holder for v4l2 device structure
>> @@ -77,6 +79,8 @@ enum domain_type {
>>  
>>  struct iris_core {
>>  	struct device				*dev;
>> +	struct device				*fw_dev;
>> +	struct qcom_scm_pas_context		*pas_ctx;
>>  	void __iomem				*reg_base;
>>  	int					irq;
>>  	struct v4l2_device			v4l2_dev;
>> diff --git a/drivers/media/platform/qcom/iris/iris_firmware.c b/drivers/media/platform/qcom/iris/iris_firmware.c
>> index 5f408024e967..0085dd7ec052 100644
>> --- a/drivers/media/platform/qcom/iris/iris_firmware.c
>> +++ b/drivers/media/platform/qcom/iris/iris_firmware.c
>> @@ -5,6 +5,7 @@
>>  
>>  #include <linux/firmware.h>
>>  #include <linux/firmware/qcom/qcom_scm.h>
>> +#include <linux/iommu.h>
>>  #include <linux/of_address.h>
>>  #include <linux/of_reserved_mem.h>
>>  #include <linux/soc/qcom/mdt_loader.h>
>> @@ -13,12 +14,15 @@
>>  #include "iris_firmware.h"
>>  
>>  #define MAX_FIRMWARE_NAME_SIZE	128
>> +#define IRIS_FW_START_ADDR	0
>>  
>>  static int iris_load_fw_to_memory(struct iris_core *core, const char *fw_name)
>>  {
>> +	struct device *fw_dev = core->fw_dev ? core->fw_dev : core->dev;
>>  	u32 pas_id = core->iris_platform_data->pas_id;
>>  	const struct firmware *firmware = NULL;
>> -	struct device *dev = core->dev;
>> +	struct qcom_scm_pas_context *pas_ctx;
>> +	struct iommu_domain *domain;
>>  	struct resource res;
>>  	phys_addr_t mem_phys;
>>  	size_t res_size;
>> @@ -29,14 +33,18 @@ static int iris_load_fw_to_memory(struct iris_core *core, const char *fw_name)
>>  	if (strlen(fw_name) >= MAX_FIRMWARE_NAME_SIZE - 4)
>>  		return -EINVAL;
>>  
>> -	ret = of_reserved_mem_region_to_resource(dev->of_node, 0, &res);
>> +	ret = of_reserved_mem_region_to_resource(core->dev->of_node, 0, &res);
>>  	if (ret)
>>  		return ret;
>>  
>>  	mem_phys = res.start;
>>  	res_size = resource_size(&res);
>>  
>> -	ret = request_firmware(&firmware, fw_name, dev);
>> +	pas_ctx = devm_qcom_scm_pas_context_alloc(fw_dev, pas_id, mem_phys, res_size);
>> +	if (IS_ERR(pas_ctx))
>> +		return PTR_ERR(pas_ctx);
>> +
>> +	ret = request_firmware(&firmware, fw_name, fw_dev);
>>  	if (ret)
>>  		return ret;
>>  
>> @@ -52,9 +60,27 @@ static int iris_load_fw_to_memory(struct iris_core *core, const char *fw_name)
>>  		goto err_release_fw;
>>  	}
>>  
>> -	ret = qcom_mdt_load(dev, firmware, fw_name,
>> -			    pas_id, mem_virt, mem_phys, res_size, NULL);
>> +	pas_ctx->use_tzmem = !!core->fw_dev;
>> +	ret = qcom_mdt_pas_load(pas_ctx, firmware, fw_name, mem_virt, NULL);
>> +	if (ret)
>> +		goto err_mem_unmap;
>> +
>> +	if (pas_ctx->use_tzmem) {
>> +		domain = iommu_get_domain_for_dev(fw_dev);
>> +		if (!domain) {
>> +			ret = -ENODEV;
>> +			goto err_mem_unmap;
>> +		}
>> +
>> +		ret = iommu_map(domain, IRIS_FW_START_ADDR, mem_phys, res_size,
>> +				IOMMU_READ | IOMMU_WRITE | IOMMU_PRIV, GFP_KERNEL);
>> +		if (ret)
>> +			goto err_mem_unmap;
>> +	}
>>  
>> +	core->pas_ctx = pas_ctx;
>> +
>> +err_mem_unmap:
>>  	memunmap(mem_virt);
>>  err_release_fw:
>>  	release_firmware(firmware);
>> @@ -62,6 +88,18 @@ static int iris_load_fw_to_memory(struct iris_core *core, const char *fw_name)
>>  	return ret;
>>  }
>>  
>> +static void iris_fw_iommu_unmap(struct iris_core *core)
>> +{
>> +	struct iommu_domain *domain;
>> +
>> +	if (!core->pas_ctx->use_tzmem)
>> +		return;
>> +
>> +	domain = iommu_get_domain_for_dev(core->fw_dev);
>> +	if (domain)
>> +		iommu_unmap(domain, IRIS_FW_START_ADDR, core->pas_ctx->mem_size);
>> +}
>> +
>>  int iris_fw_load(struct iris_core *core)
>>  {
>>  	const struct tz_cp_config *cp_config;
>> @@ -79,10 +117,10 @@ int iris_fw_load(struct iris_core *core)
>>  		return -ENOMEM;
>>  	}
>>  
>> -	ret = qcom_scm_pas_auth_and_reset(core->iris_platform_data->pas_id);
>> +	ret = qcom_scm_pas_prepare_and_auth_reset(core->pas_ctx);
>>  	if (ret)  {
>>  		dev_err(core->dev, "auth and reset failed: %d\n", ret);
>> -		return ret;
>> +		goto err_unmap;
>>  	}
>>  
>>  	for (i = 0; i < core->iris_platform_data->tz_cp_config_data_size; i++) {
>> @@ -93,17 +131,31 @@ int iris_fw_load(struct iris_core *core)
>>  						     cp_config->cp_nonpixel_size);
>>  		if (ret) {
>>  			dev_err(core->dev, "qcom_scm_mem_protect_video_var failed: %d\n", ret);
>> -			qcom_scm_pas_shutdown(core->iris_platform_data->pas_id);
>> -			return ret;
>> +			goto err_pas_shutdown;
>>  		}
>>  	}
>>  
>> +	return 0;
>> +
>> +err_pas_shutdown:
>> +	qcom_scm_pas_shutdown(core->pas_ctx->pas_id);
>> +err_unmap:
>> +	iris_fw_iommu_unmap(core);
>> +
>>  	return ret;
>>  }
>>  
>>  int iris_fw_unload(struct iris_core *core)
>>  {
>> -	return qcom_scm_pas_shutdown(core->iris_platform_data->pas_id);
>> +	int ret;
>> +
>> +	ret = qcom_scm_pas_shutdown(core->pas_ctx->pas_id);
>> +	if (ret)
>> +		return ret;
>> +
>> +	iris_fw_iommu_unmap(core);
>> +
>> +	return ret;
>>  }
>>  
>>  int iris_set_hw_state(struct iris_core *core, bool resume)
>>
>> -- 
>> 2.34.1
>>