Re: [PATCH 1/3] crypto: ccp - Add function to allocate and free memory using DMA APIs

["NK, JESHWANTHKUMAR" <jeshwanthkumar.nk@xxxxxxx>]

Hi Christoph,

On 27-Oct-23 10:54 AM, Christoph Hellwig wrote:
> On Wed, Oct 25, 2023 at 12:26:58PM +0530, jeshwank wrote:
> > +	tee_buf->vaddr = dma_alloc_coherent(psp->dev, size, &tee_buf->dma, gfp);
> > +	if (!tee_buf->vaddr || !tee_buf->dma) {
> > +		kfree(tee_buf);
> > +		return NULL;
> > +	}
> > +
> > +	tee_buf->size = size;
> > +
> > +	/* Check whether IOMMU is present. If present, translate IOVA
> > +	 * to physical address, else the dma handle is the physical
> > +	 * address.
> > +	 */
> > +	dom = iommu_get_domain_for_dev(psp->dev);
> > +	if (dom)
> > +		tee_buf->paddr = iommu_iova_to_phys(dom, tee_buf->dma);
> > +	else
> No, you can't mix the DMA API and iommu API.  You need to stick to one
> or the other.
Can you please elaborate?