Folks,
On Fri, Jun 10, 2022 at 11:08:02AM +0300, Serge Semin wrote:
> A basic device-specific linear memory mapping was introduced back in
> commit ("dma: Take into account dma_pfn_offset") as a single-valued offset
> preserved in the device.dma_pfn_offset field, which was initialized for
> instance by means of the "dma-ranges" DT property. Afterwards the
> functionality was extended to support more than one device-specific region
> defined in the device.dma_range_map list of maps. But all of these
> improvements concerned a single pointer, page or sg DMA-mapping methods,
> while the system resource mapping function turned to miss the
> corresponding modification. Thus the dma_direct_map_resource() method now
> just casts the CPU physical address to the device DMA address with no
> dma-ranges-based mapping taking into account, which is obviously wrong.
> Let's fix it by using the phys_to_dma_direct() method to get the
> device-specific bus address from the passed memory resource for the case
> of the directly mapped DMA.
So any comment on the suggest modification? Any notes against or for?
-Sergey
>
> Fixes: 25f1e1887088 ("dma: Take into account dma_pfn_offset")
> Signed-off-by: Serge Semin <[email protected]>
>
> ---
>
> After a long discussion with Christoph and Robin regarding this patch
> here:
> https://lore.kernel.org/lkml/[email protected]
> and here
> https://lore.kernel.org/linux-pci/[email protected]/
> It was decided to consult with wider maintainers audience whether it's ok
> to accept the change as is or a more sophisticated solution needs to be
> found for the non-linear direct MMIO mapping.
>
> Cc: Christoph Hellwig <[email protected]>
> Cc: Robin Murphy <[email protected]>
> Cc: Manivannan Sadhasivam <[email protected]>
>
> file: arch/arm/mach-orion5x/board-dt.c
> Cc: Andrew Lunn <[email protected]>
> Cc: Sebastian Hesselbarth <[email protected]>
> Cc: Gregory Clement <[email protected]>
> Cc: [email protected]
>
> file: drivers/crypto/marvell/cesa/cesa.c
> Cc: Srujana Challa <[email protected]>
> Cc: Arnaud Ebalard <[email protected]>
> Cc: Boris Brezillon <[email protected]>
> Cc: [email protected]
>
> file: drivers/dma/{fsl-edma-common.c,pl330.c,sh/rcar-dmac.c}
> Cc: Vinod Koul <[email protected]>
> Cc: [email protected]
>
> file:
> arch/arm/boot/dts/{vfxxx.dtsi,ls1021a.dtsi,imx7ulp.dtsi,fsl-ls1043a.dtsi}
> Cc: Shawn Guo <[email protected]>
> Cc: Sascha Hauer <[email protected]>
> Cc: Li Yang <[email protected]>
> Cc: [email protected]
>
> file: arch/arm/boot/dts/r8a77*.dtsi, arch/arm64/boot/dts/renesas/r8a77*.dtsi
> Cc: Geert Uytterhoeven <[email protected]>
> Cc: Magnus Damm <[email protected]>
> Cc: [email protected]
>
> file: drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
> Cc: Alex Deucher <[email protected]>
> Cc: "Christian König" <[email protected]>
> Cc: "Pan, Xinhui" <[email protected]>
>
> file: drivers/gpu/drm/virtio/virtgpu_vram.c
> Cc: David Airlie <[email protected]>
> Cc: Gerd Hoffmann <[email protected]>
>
> file: drivers/media/common/videobuf2/videobuf2-dma-contig.c
> Cc: Tomasz Figa <[email protected]>
> Cc: Marek Szyprowski <[email protected]>
>
> file: drivers/misc/habanalabs/common/memory.c
> Cc: Oded Gabbay <[email protected]>
> Cc: Arnd Bergmann <[email protected]>
> Cc: Greg Kroah-Hartman <[email protected]>
>
> file: drivers/mtd/nand/raw/qcom_nandc.c
> Cc: Manivannan Sadhasivam <[email protected]>
>
> file:
> arch/arm64/boot/dts/qcom/{ipq8074.dtsi,ipq6018.dtsi,qcom-sdx55.dtsi,qcom-ipq4019.dtsi,qcom-ipq8064.dtsi}
> Cc: Andy Gross <[email protected]>
> Cc: Bjorn Andersson <[email protected]>
> Cc: [email protected]
>
> file: drivers/net/ethernet/marvell/octeontx2/af/rvu.c
> Cc: Sunil Goutham <[email protected]>
> Cc: Linu Cherian <[email protected]>
> Cc: Geetha sowjanya <[email protected]>
>
> file: drivers/ntb/ntb_transport.c
> Cc: Jon Mason <[email protected]>
> Cc: Dave Jiang <[email protected]>
> Cc: [email protected]
> ---
> kernel/dma/direct.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
> index 9743c6ccce1a..bc06db74dfdb 100644
> --- a/kernel/dma/direct.c
> +++ b/kernel/dma/direct.c
> @@ -497,7 +497,7 @@ int dma_direct_map_sg(struct device *dev, struct
> scatterlist *sgl, int nents,
> dma_addr_t dma_direct_map_resource(struct device *dev, phys_addr_t paddr,
> size_t size, enum dma_data_direction dir, unsigned long attrs)
> {
> - dma_addr_t dma_addr = paddr;
> + dma_addr_t dma_addr = phys_to_dma_direct(dev, paddr);
>
> if (unlikely(!dma_capable(dev, dma_addr, size, false))) {
> dev_err_once(dev,
> --
> 2.35.1
>
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