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SubjectRe: [PATCH v3 2/2] x86/PCI: sta2x11: use default DMA address translation
On Thu, Nov 07, 2019 at 04:06:45PM +0100, Nicolas Saenz Julienne wrote:
> The devices found behind this PCIe chip have unusual DMA mapping
> constraints as there is an AMBA interconnect placed in between them and
> the different PCI endpoints. The offset between physical memory
> addresses and AMBA's view is provided by reading a PCI config register,
> which is saved and used whenever DMA mapping is needed.
> It turns out that this DMA setup can be represented by properly setting
> 'dma_pfn_offset', 'dma_bus_mask' and 'dma_mask' during the PCI device
> enable fixup. And ultimately allows us to get rid of this device's
> custom DMA functions.
> Aside from the code deletion and DMA setup, sta2x11_pdev_to_mapping() is
> moved to avoid warnings whenever CONFIG_PM is not enabled.
> Signed-off-by: Nicolas Saenz Julienne <>
> Reviewed-by: Christoph Hellwig <>
> ---
> Changed since v1:
> - use variable to avoid recalculating AMBA's max address
> - remove x86's dma-direct.h as it's not longer needed
> arch/x86/Kconfig | 1 -
> arch/x86/include/asm/device.h | 3 -
> arch/x86/include/asm/dma-direct.h | 9 --
> arch/x86/pci/sta2x11-fixup.c | 135 ++++++------------------------
> 4 files changed, 26 insertions(+), 122 deletions(-)
> delete mode 100644 arch/x86/include/asm/dma-direct.h

Ok, I have only 2/2 in my mbox so in the future, when sending a whole
set, make sure you Cc everybody on all the patches so that people can
see the whole thing.

Then, I went and read back all the discussion about this cleanup and
how it is hard to test it because it is not in PCs but in automotive

Long story, short, I like patches with negative diffstats :) so I could
take it through tip unless Christoph has different plans for this.



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