Messages in this thread | | | Date | Thu, 18 Dec 2014 14:02:17 -0500 | From | Murali Karicheri <> | Subject | Re: [RFC PATCH 1/2] common: dma-mapping: introduce dma_get_parent_cfg() helper |
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On 12/17/2014 07:09 PM, Arnd Bergmann wrote: > On Wednesday 17 December 2014 18:24:43 Murali Karicheri wrote: >> On 12/17/2014 04:56 PM, Arnd Bergmann wrote: >>> On Wednesday 17 December 2014 13:02:23 Murali Karicheri wrote: >>> >>> What's wrong with using arch_setup_dma_ops() from PCI as suggested >>> previously? >>> > > +Will Deacon > >> I had originally written a code based on that line as below. But >> dma-ranges property is also used by ppc and other architectures in the >> pci device DT node. So I wasn't sure how this code impact PCI driver >> functionality on those platforms. Hence used a simpler change as all >> that is needed for keystone is to get the dma_pfn_offset rightly set in >> the pci slave device. > > But in your patch, you don't call arch_setup_dma_ops() at all. > >> Initially I had a function implemented as below for this in of_pci.c. >> >> + * of_pci_dma_configure - Setup DMA configuration for a pci device >> + * @dev: pci device to apply DMA configuration >> + * >> + * Try to get devices's DMA configuration from DT and update it >> + * accordingly. This is a similar to of_dma_configure() for platform >> + * devices. >> + * >> + */ >> +void of_pci_dma_configure(struct pci_dev *dev) >> +{ >> + struct device *host_bridge, *parent; >> + struct pci_bus *bus = dev->bus; >> + u64 dma_addr, paddr, size; >> + int ret; >> + >> + while (!pci_is_root_bus(bus)) >> + bus = bus->parent; >> + host_bridge = bus->bridge; >> + >> + parent = host_bridge->parent; >> + if (parent->of_node) { > > so far it looks good, although we may want to introduce > a helper function to get the of_node.
Will add
> >> + /* >> + * if dma-coherent property exist, call arch hook to setup >> + * dma coherent operations. >> + */ >> + if (of_dma_is_coherent(parent->of_node)) { >> + set_arch_dma_coherent_ops(&dev->dev); >> + dev_info(&dev->dev, "device is dma coherent\n"); >> + } > > set_arch_dma_coherent_ops no longer exists. Just keep the flag in a > local variable
Ok.
> >> + /* >> + * if dma-ranges property doesn't exist - just return else >> + * setup the dma offset >> + */ >> + ret = of_dma_get_range(parent->of_node,&dma_addr, >> &paddr,&size); >> + if (ret< 0) { >> + dev_info(&dev->dev, "no dma range information to >> setup\n"); >> + printk("no dma range information to setup\n"); >> + return; >> + } >> + >> + /* DMA ranges found. Calculate and set dma_pfn_offset */ >> + dev->dev.dma_pfn_offset = PFN_DOWN(paddr - dma_addr); >> + dev_info(&dev->dev, "dma_pfn_offset(%#08lx)\n", >> dev->dev.dma_pfn_offset); > > Same for the offset and size here, then pass all of the above into > arch_setup_dma_ops. This is also where we need to hook up the iommu > support once we decide how to make that work with the ARM SMMU.
Ok. I will make this similar to of_dma_configure() that can be called from pci/probe.c
Murali > > Will, I think we may have a problem on ARM64 now, since we only replaced > set_arch_dma_coherent_ops on ARM32 but not ARM64. Can you send a fix for > this? Without that, we don't have any coherent operations on ARM64 any > more, unless I'm missing something. > > Arnd > -- > To unsubscribe from this list: send the line "unsubscribe linux-pci" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html
-- Murali Karicheri Linux Kernel, Texas Instruments
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