On Tuesday, May 06, 2014 10:59 PM, Arnd Bergmann wrote: > On Tuesday 06 May 2014 19:03:52 Kishon Vijay Abraham I wrote: > > In DRA7, the cpu sees 32bit address, but the pcie controller can see only 28bit > > address. So whenever the cpu issues a read/write request, the 4 most > > significant bits are used by L3 to determine the target controller. > > For example, the cpu reserves 0x2000_0000 - 0x2FFF_FFFF for PCIe controller but > > the PCIe controller will see only (0x000_0000 - 0xFFF_FFF). So for programming > > the outbound translation window the *base* should be programmed as 0x000_0000. > > Whenever we try to write to say 0x2000_0000, it will be translated to whatever > > we have programmed in the translation window with base as 0x000_0000. > > > > Cc: Bjorn Helgaas <bhelgaas@xxxxxxxxxx> > > Cc: Marek Vasut <marex@xxxxxxx> > > Signed-off-by: Kishon Vijay Abraham I <kishon@xxxxxx> > > Acked-by: Jingoo Han <jg1.han@xxxxxxxxxxx> > > Acked-by: Mohit Kumar <mohit.kumar@xxxxxx> > > Sorry, but NAK. > > We have a standard 'dma-ranges' property to handle this, so use it. > > See the x-gene PCIe driver patches for an example. Please also talk > to Santosh about it, as he is implementing generic support for > parsing dma-ranges in platform devices at the moment. Hi Arnd, Do you mean the following patch? http://www.spinics.net/lists/kernel/msg1737725.html Thank you. Best regards, Jingoo Han > > I also suspect you will have to implement swiotlb support to make > generic PCI devices work behind this bridge. Otherwise you end up > with random physical addresses passed into DMA registers. -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
