Re: [PATCH v2 09/15] accel/qda: Add DMA-backed GEM objects and memory manager integration

[Ekansh Gupta]

On 18-08-2026 09:18, Dmitry Baryshkov wrote:
> On Mon, Aug 17, 2026 at 10:17:44AM +0530, Ekansh Gupta wrote:
>> Introduce DMA-coherent buffer management for the QDA driver, wiring
>> together the GEM subsystem, the IOMMU memory manager, and a DMA
>> allocation backend.
>>
>> +
>> +/*
>> + * The DSP identifies the IOMMU context bank from the upper bits of the 
>> address,
>> + * so the stream ID is folded into every address handed to it. The DMA API 
>> only
>> + * ever sees the plain 32-bit address, which is why the context bank 
>> devices are
>> + * created with a 32-bit DMA mask.
>> + */
>> +static dma_addr_t get_actual_dma_addr(struct qda_gem_obj *gem_obj)
> 
> Let me propose a very simple rule for you. Unless you know what you are
> doing, all function, struct and macro names should start with qda_. The
> to_qda_foo(), I think, is the only example up to now where you don't need
> to have the prefix.
ack>
>> +{
>> +    return gem_obj->dma_addr - ((u64)gem_obj->iommu_dev->sid << 32);
>> +}
>> +
>> +static void setup_gem_object(struct qda_gem_obj *gem_obj, void *virt,
>> +                         dma_addr_t dma_addr, struct qda_iommu_device 
>> *iommu_dev)
>> +{
>> +    gem_obj->virt = virt;
>> +    gem_obj->dma_addr = dma_addr;
>> +    gem_obj->iommu_dev = iommu_dev;
>> +}
>> +
>> +static void cleanup_gem_object_fields(struct qda_gem_obj *gem_obj)
>> +{
>> +    gem_obj->virt = NULL;
>> +    gem_obj->dma_addr = 0;
>> +    gem_obj->iommu_dev = NULL;
>> +}
> 
> These functions are called only once. Inline them.
ack>
>> +
>