Messages in this thread | | | Date | Mon, 22 Dec 2014 16:40:43 -0500 | From | Murali Karicheri <> | Subject | Re: [RFC v1 PATCH 1/2] of/pci: add of_pci_dma_configure() update dma configuration |
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On 12/22/2014 02:43 PM, Arnd Bergmann wrote: > On Monday 22 December 2014 12:46:12 Murali Karicheri wrote: >> On 12/18/2014 05:29 PM, Arnd Bergmann wrote: >>> On Thursday 18 December 2014 17:07:04 Murali Karicheri wrote: >>>> Add of_pci_dma_configure() to allow updating the dma configuration >>>> of the pci device using the configuration from the parent of >>>> the root bridge device. >>>> + /* >>>> + * Set it to coherent_dma_mask by default if the architecture >>>> + * code has not set it. >>>> + */ >>>> + if (!dev->dma_mask) >>>> + dev->dma_mask =&dev->coherent_dma_mask; >>>> + >>>> + ret = of_dma_get_range(parent_np,&dma_addr,&paddr,&size); >>>> + if (ret< 0) { >>>> + dma_addr = offset = 0; >>>> + size = dev->coherent_dma_mask; >>> >>> Can you check one thing here? I believe the size argument as returned >>> from of_dma_get_range is inclusive (e.g. 0x100000000), while the coherent >>> mask by definition is exlusive (e.g. 0xffffffff), so the size needs to >>> be adapted here. I haven't checked all the code here though, so I may >>> be wrong. >> >> size returned by of_dma_get_range() is inclusive as you indicated. Fromt >> the grep of dma-ranges in arch/arm/boot/dts, I see >> >> arch/arm/boot/dts/keystone.dtsi: dma-ranges =<0x80000000 0x8 >> 0x00000000 0x80000000>; >> arch/arm/boot/dts/keystone.dtsi: dma-ranges; >> arch/arm/boot/dts/r8a7790.dtsi: dma-ranges =<0x42000000 0 0x40000000 0 >> 0x40000000 0 0x80000000 >> arch/arm/boot/dts/integratorap.dts: dma-ranges =<0x80000000 0x0 >> 0x80000000>; >> arch/arm/boot/dts/r8a7791.dtsi: dma-ranges =<0x42000000 0 0x40000000 0 >> 0x40000000 0 0x80000000 >> >> So I guess I need to change the code to >> >> >> + ret = of_dma_get_range(parent_np,&dma_addr,&paddr,&size); >> >> + if (ret< 0) { >> >> + dma_addr = offset = 0; >> >> + size = dev->coherent_dma_mask + 1; > > Right. > >>>> + } else { >>>> + offset = PFN_DOWN(paddr - dma_addr); >>>> + dev_dbg(dev, "dma_pfn_offset(%#08lx)\n", dev->dma_pfn_offset); >>>> + } >>>> + dev->dma_pfn_offset = offset; >>>> + >>>> + coherent = of_dma_is_coherent(parent_np); >>>> + dev_dbg(dev, "device is%sdma coherent\n", >>>> + coherent ? " " : " not "); >>>> + >>>> + arch_setup_dma_ops(dev, dma_addr, size, NULL, coherent); >>> >>> Basically, I would use limit the size argument we pass into >>> arch_setup_dma_ops to the minimum of 'size' and 'dma_mask' here, >>> after converting into the same format. We should make sure we do the >>> same thing for platform_device as well, so it might be better to do >>> it inside of arch_setup_dma_ops instead. >> >> Do you think following changes will work? >> >> +++ b/arch/arm/mm/dma-mapping.c >> @@ -2052,9 +2052,10 @@ void arch_setup_dma_ops(struct device *dev, u64 >> dma_base, u64 size, >> struct iommu_ops *iommu, bool coherent) >> { >> struct dma_map_ops *dma_ops; >> + u64 temp_size = min((*(dev->dma_mask) + 1), size); >> >> dev->archdata.dma_coherent = coherent; >> - if (arm_setup_iommu_dma_ops(dev, dma_base, size, iommu)) >> + if (arm_setup_iommu_dma_ops(dev, dma_base, temp_size, iommu)) >> >> If you agree, I will post v1 of the patch with these updates. Let me >> know. I did some basic tests on Keystone with these changes and it works >> fine. > > It's not exactly what I meant. My main point was that we need to limit > dev->dma_mask to (size-1) here, but you are not touching that.
if you mean overriding the dev->dma_mask to min((*dev->dma_mask), size-1), then I am getting the error "Coherent DMA mask 0x7fffffff (pfn 0x780000-0x800000) covers a smaller range of system memory than the DMA zone pfn 0x0-0x880000) when the devices on Keystone tries to set the dma mask. Something wrong and I need to look into the code.
> either change the two functions in which we first assign the dma_mask > (platform and pci bus), or set it again in arch_setup_dma_ops (on each > architecture implementing it), either way would work. Someone else > might have a stronger opinion on that matter. > > For arm_setup_iommu_dma_ops, passing the original size is probably > best. > > Arnd
-- Murali Karicheri Linux Kernel, Texas Instruments
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