On 05/22/2018 11:52 AM, Marek Vasut wrote: > On 05/22/2018 10:10 AM, Arnd Bergmann wrote: >> On Tue, May 22, 2018 at 12:05 AM, Marek Vasut <marek.vasut@xxxxxxxxx> wrote: >>> From: Phil Edworthy <phil.edworthy@xxxxxxxxxxx> >>> >>> The PCIe DMA controller on RCar Gen2 and earlier is on 32bit bus, >>> so limit the DMA range to 32bit. >>> >>> Signed-off-by: Phil Edworthy <phil.edworthy@xxxxxxxxxxx> >>> Signed-off-by: Marek Vasut <marek.vasut+renesas@xxxxxxxxx> >>> Cc: Arnd Bergmann <arnd@xxxxxxxx> >>> Cc: Geert Uytterhoeven <geert+renesas@xxxxxxxxx> >>> Cc: Phil Edworthy <phil.edworthy@xxxxxxxxxxx> >>> Cc: Simon Horman <horms+renesas@xxxxxxxxxxxx> >>> Cc: Wolfram Sang <wsa@xxxxxxxxxxxxx> >>> Cc: linux-renesas-soc@xxxxxxxxxxxxxxx >>> To: linux-pci@xxxxxxxxxxxxxxx >>> --- >>> NOTE: I'm aware of https://patchwork.kernel.org/patch/9495895/ , but the >>> discussion seems to have gone way off, so I'm sending this as a >>> RFC. Any feedback on how to do this limiting properly would be nice. >> >> Doing it in the driver is clearly not appropriate, we must do this in >> common code. If I remember correctly, it's specifically ARM64 that is >> broken here, it incorrectly allows setting a DMA mask to 64 bit >> when that is not available. > > Yep, that's correct. ARM64 with devices mapping tremendous amounts of > memory. So did anything change since that discussion references in the NOTE? Bump ? I think it'd be nice to sort this out once and for all, since I doubt it's just this controller that has such a limitation. -- Best regards, Marek Vasut
