On Sun, Sep 28, 2025 at 06:02:25PM +0300, Leon Romanovsky wrote:
> @@ -273,13 +272,16 @@ static dma_addr_t dma_4u_map_page(struct device *dev,
> struct page *page,
> u32 bus_addr, ret;
> unsigned long iopte_protection;
>
> + if (attrs & DMA_ATTR_MMIO)
> + goto bad_no_ctx;
> +
> iommu = dev->archdata.iommu;
> strbuf = dev->archdata.stc;
>
> if (unlikely(direction == DMA_NONE))
> goto bad_no_ctx;
>
> - oaddr = (unsigned long)(page_address(page) + offset);
> + oaddr = (unsigned long)(phys_to_virt(phys));
> npages = IO_PAGE_ALIGN(oaddr + sz) - (oaddr & IO_PAGE_MASK);
> npages >>= IO_PAGE_SHIFT;
This should be cleaned up some more:
oaddr = (unsigned long)(page_address(page) + offset);
ret = bus_addr | (oaddr & ~IO_PAGE_MASK);
base_paddr = __pa(oaddr & IO_PAGE_MASK);
Makes no sense to phys_to_virt() then __pa() on that result. Drop oaddr.
Then I would copy and paste the comment from mips about DMA_ATTR_MMIO
> @@ -367,13 +366,16 @@ static dma_addr_t dma_4v_map_page(struct device *dev,
> struct page *page,
> dma_addr_t bus_addr, ret;
> long entry;
>
> + if (attrs & DMA_ATTR_MMIO)
> + goto bad;
> +
> iommu = dev->archdata.iommu;
> atu = iommu->atu;
>
> if (unlikely(direction == DMA_NONE))
> goto bad;
>
> - oaddr = (unsigned long)(page_address(page) + offset);
> + oaddr = (unsigned long)(phys_to_virt(phys));
> npages = IO_PAGE_ALIGN(oaddr + sz) - (oaddr & IO_PAGE_MASK);
> npages >>= IO_PAGE_SHIFT;
Same remarks here
> +static dma_addr_t iounit_map_phys(struct device *dev, phys_addr_t phys,
> + size_t len, enum dma_data_direction dir, unsigned long attrs)
> {
> - void *vaddr = page_address(page) + offset;
> + void *vaddr = phys_to_virt(phys);
> struct iounit_struct *iounit = dev->archdata.iommu;
> unsigned long ret, flags;
iounit_get_area() does not seem to need vaddr:
npages = ((vaddr & ~PAGE_MASK) + size + (PAGE_SIZE-1)) >> PAGE_SHIFT;
~PAGE_MASK is page_offset()
iopte = MKIOPTE(__pa(vaddr & PAGE_MASK));
__pa(phys_to_virt(pa)) again:
iopte = MKIOPTE(PAGE_ALIGN(pa));
vaddr = IOUNIT_DMA_BASE + (scan << PAGE_SHIFT) + (vaddr & ~PAGE_MASK);
page_offset, then it replaces vaddr.
So I'd tidy this too.
> @@ -202,10 +204,10 @@ static dma_addr_t __sbus_iommu_map_page(struct device
> *dev, struct page *page,
> * We expect unmapped highmem pages to be not in the cache.
> * XXX Is this a good assumption?
> * XXX What if someone else unmaps it here and races us?
> */
At least ARM32 has code that seems to say these assumptions are not
always true.. Oh well.
Jason
