Re: [PATCH v2 1/2] of/pci: add of_pci_dma_configure() update dma configuration
From: Murali Karicheri
Date: Mon Jan 05 2015 - 18:36:23 EST
On 01/05/2015 05:26 PM, Arnd Bergmann wrote:
On Monday 05 January 2015 15:06:57 Murali Karicheri wrote:
On 01/03/2015 04:37 PM, Arnd Bergmann wrote:
Yes, but we also need to pass a PCI device specific identifier along
with the root bus node, because some iommu drivers take the PCI
bus/device/function number into account for creating per-function
i/o page tables.
...
I will post v3 of the patch with what is agreed before in my response
and I understand there is no additional change required based on this
particular discussion about iommu. Right?
Actually regarding the bit I wrote above, it might be helpful to pass
the PCI_DEVID() into both of_iommu_configure and of_dma_configure.
While this may or may not be sufficient, I think there is no question
about it being needed for the ARM SMMU with PCI, so we may as well add
it at the point when you touch the same lines already. In the platform
bus case, just pass zero here.
Arnd,
PCI_DEVID() is defined as
#define PCI_DEVID(bus, devfn) ((((u16)(bus)) << 8) | (devfn))
So PCI_DEVID of 0 is a valid PCI DEVID.
How about checking if the device is PCI in of_iommu_configure() using
dev_is_pci(dev) macro and return immediately for PCI? Need to include
pci.h in this file though.
Some of the iommu drivers already include this.
a0868495@ares-ubuntu:~/projects/linux-keystone$ grep -r pci.h drivers/iommu/
drivers/iommu/amd_iommu_v2.c:#include <linux/pci.h>
drivers/iommu/dmar.c:#include <linux/pci.h>
drivers/iommu/amd_iommu_types.h:#include <linux/pci.h>
drivers/iommu/amd_iommu.c:#include <linux/pci.h>
drivers/iommu/fsl_pamu_domain.c:#include <sysdev/fsl_pci.h>
drivers/iommu/iommu.c:#include <linux/pci.h>
drivers/iommu/intel-iommu.c:#include <linux/pci.h>
drivers/iommu/intel_irq_remapping.c:#include <linux/pci.h>
drivers/iommu/arm-smmu.c:#include <linux/pci.h>
drivers/iommu/amd_iommu_init.c:#include <linux/pci.h>
drivers/iommu/irq_remapping.c:#include <linux/pci.h>
This will allow us to re-visit this later for IOMMU support for PCI
without polluting the API.
Murali
Arnd
--
Murali Karicheri
Linux Kernel, Texas Instruments
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