Re: [PATCH V3] pci: exynos: split into two parts such as Synopsys part and Exynos part

[Pratyush Anand <pratyush.anand-qxv4g6HH51o@public.gmane.org>]

On Mon, Sep 23, 2013 at 01:32:54PM +0800, Kishon Vijay Abraham I wrote:
> Hi Pratyush,
> 
> On Monday 23 September 2013 09:44 AM, Pratyush Anand wrote:
> > Hi Kishon,
> > 
> > 
> > On Sun, Sep 22, 2013 at 07:16:34PM +0800, Kishon Vijay Abraham I wrote:
> >> Hi Arnd,
> >>
> >> Thanks for replying :-)
> >>
> >> On Sunday 22 September 2013 03:33 AM, Arnd Bergmann wrote:
> >>> On Saturday 21 September 2013, Kishon Vijay Abraham I wrote:
> >>>> {
> >>>>         u32 val;
> >>>>         void __iomem *val1;
> >>>>         void __iomem *dbi_base = pp->dbi_base;
> >>>>
> >>>>         /* Program viewport 0 : INBOUND : MEMORY*/
> >>>>         val = PCIE_ATU_REGION_INBOUND | (0 & 0xF);
> >>>>         dw_pcie_writel_rc(pp, val, dbi_base + PCIE_ATU_VIEWPORT);
> >>>>         val1 = ioremap(0x80000000, 0x5fffffff);
> >>>
> >>> The ioremap here makes no sense at all, and I suspect it will fail anyway,
> >>> because you exhaust the vmalloc area size, but since the value is not
> >>> used anywhere, it won't matter.
> >>>
> >>>>         dw_pcie_writel_rc(pp, 0x80000000, dbi_base + PCIE_ATU_LOWER_BASE);
> >>>>         dw_pcie_writel_rc(pp, 0, dbi_base + PCIE_ATU_UPPER_BASE);
> >>>>         /* in_mem_size must be in power of 2 */
> >>>>         dw_pcie_writel_rc(pp, 0x5FFFFFFF, dbi_base + PCIE_ATU_LIMIT);
> > 
> > This is wrong. You should program here 0xBFFFFFFF.
> 
> That dint help :-(
> 
> Btw if we hadn't programmed inbound translation table, the address will go
> untranslated (according to the data book). I guess that's how it was working
> for Jingoo Han.
> 
> **
> 3.10.4
> Inbound iATU Operation
> 
> When there is no match, then the address is untranslated
> **
> 

ok.. so it seems that you might not be getting non-fatal error because
of address translation. I am not working with PCIe for a long time,
but if I remember correctly other reason for getting this error were
unsupported read/write request size. Although, you have said that MRRS
is 512 for your RC. Can you cross check both programmed MPS and MRRS
in your RC as well as your EP (ethernet card). May be you can share
Content of PCIe Capability Device Control Register (Offset 08h) for
both RC and EP.

Regards
Pratyush



> > 
> > Translation rule is as follows:
> > 
> > Region between "Start Address" and "End Address" is translated to
> > "Target Address" with region size = "End Address" - "Start Address".
> > Where: Start Address = (PCIE_ATU_UPPER_BASE | PCIE_ATU_LOWER_BASE)
> >         End Address = (PCIE_ATU_UPPER_BASE | PCIE_ATU_LIMIT)
> >         Target Address = (PCIE_ATU_UPPER_TARGET | PCIE_ATU_LOWER_TARGET) 
> > 
> >>>>         dw_pcie_writel_rc(pp, 0x80000000, dbi_base + PCIE_ATU_LOWER_TARGET);
> >>>>         dw_pcie_writel_rc(pp, 0, dbi_base + PCIE_ATU_UPPER_TARGET);
> >>>
> >>> These numbers need to come from somewhere, you shouldn't just hardcode them, 
> >>
> >> right. I'm still in the process of getting it work ;-)
> >>>
> >>> I guess you should either program an inbound window covering the entire 64-bit
> >>> address space, or you should look at the top-level "memory" nodes to find
> >>> the location of physical RAM.
> >>>
> >>> I can't see anything wrong with the way it's set up though, unless you have
> >>> an IOMMU. Can you confirm that there is no IOMMU (aka SMMU) in your system
> >>> that handles the PCIe root complex?
> >>
> >> There is a MMU for PCIe root complex but that's disabled.
> >>>
> >>>> I somehow starting to doubt the DMA address programmed in the ethernet card
> >>>> which is in my RAM address range (0x80000000 to 0xBFFFFFFF). Should this
> >>>> address be programmed in the BAR of the ethernet card? How should it be done?
> >>>
> >>> No, it should not be in the BAR. The ethernet device driver calls dma_map_*
> >>> or pci_map_* interfaces to get a valid token that can be passed into the
> >>> device registers that are starting the DMA. You have to ensure that the
> >>> dma_map_ops for the device return the value that is set up in the translation.
> >>>
> >>> The normal case is an identity mapping between device DMA space and host
> >>> memory space, i.e. PCIE_ATU_LOWER_TARGET == PCIE_ATU_LOWER_BASE, so
> >>> in the dma_map_single implementation, phys_addr_t == dma_addr_t.
> >>>
> >>> If you set up the dma_addr_t space to start at 0 instead, you have to add
> >>> the offset in the dma_map_ops.
> >>
> >> My DMA address is in 0x80000000 to 0xBFFFFFFF range and I program my inbound
> >> translation for this range. Not sure what is missing still :-(
> > 
> > Hope, above modification helps. Let me know.
> > 
> > Regards
> > Pratyush
> >>
> >> Thanks
> >> Kishon
> 
> Thanks
> Kishon
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