On Thu, Apr 14, 2016 at 8:25 PM, Lorenzo Pieralisi
<lorenzo.pieralisi@xxxxxxx> wrote:
> On DT based systems, the of_dma_configure() API implements DMA configuration
> for a given device. On ACPI systems an API equivalent to of_dma_configure()
> is missing which implies that it is currently not possible to set-up DMA
> operations for devices through the ACPI generic kernel layer.
>
> This patch fills the gap by introducing acpi_dma_configure/deconfigure()
> calls, that carry out IOMMU configuration through IORT (on systems where
> it is present) and call arch_setup_dma_ops(...) with the retrieved
> parameters.
>
> The DMA range size passed to arch_setup_dma_ops() is sized according
> to the device coherent_dma_mask (starting at address 0x0), mirroring the
> DT probing path behaviour when a dma-ranges property is not provided
> for the device being probed; this changes the current arch_setup_dma_ops()
> call parameters in the ACPI probing case, but since arch_setup_dma_ops()
> is a NOP on all architectures but ARM/ARM64 this patch does not change
> the current kernel behaviour on them.
>
> This patch updates ACPI and PCI core code to use the newly introduced
> acpi_dma_configure function, providing the same functionality
> as of_dma_configure on ARM systems and leaving behaviour unchanged
> for all other arches.
>
Nitpicks below.
> --- a/drivers/acpi/iort.c
> +++ b/drivers/acpi/iort.c
> @@ -72,6 +72,31 @@ int iort_iommu_set_node(struct iommu_ops *ops, struct acpi_iort_node *node,
> return 0;
> }
>
> +/**
> + * iort_iommu_get_node - Retrieve iort_iommu_node associated with an IORT node.
> + *
> + * @node: IORT table node to be looked-up
> + *
> + * Returns: iort_iommu_node pointer on success
> + * NULL on failure
> + */
> +static struct iort_iommu_node *iort_iommu_get_node(struct acpi_iort_node *node)
> +{
> + struct iort_iommu_node *iommu_node;
> +
> + spin_lock(&iort_iommu_lock);
> + list_for_each_entry(iommu_node, &iort_iommu_list, list) {
> + if (iommu_node->node == node)
> + goto found;
> + }
> +
> + iommu_node = NULL;
> +found:
> + spin_unlock(&iort_iommu_lock);
> +
> + return iommu_node;
Ouch, and why not to
strut iommu_node = NULL;
lock
list for each() {
if ()
break;
}
unlock
return iommu_node;
?
> +}
> +/**
> + * iort_iommu_configure - Set-up IOMMU configuration for a device.
> + *
> + * @dev: device that requires IOMMU set-up
> + *
> + * Returns: iommu_ops pointer on configuration success
> + * NULL on configuration failure
> + */
> +struct iommu_ops *iort_iommu_configure(struct device *dev)
> +{
> + struct acpi_iort_node *node, *parent;
> + struct iommu_ops *ops = NULL;
> + struct iommu_fwspec fwspec;
> + struct iort_iommu_node *iommu_node;
> + u32 rid = 0, devid = 0;
> +
> + if (dev_is_pci(dev)) {
> + struct pci_bus *bus = to_pci_dev(dev)->bus;
> +
> + pci_for_each_dma_alias(to_pci_dev(dev), __get_pci_rid,
> + &rid);
> +
> + node = iort_scan_node(ACPI_IORT_NODE_PCI_ROOT_COMPLEX,
> + iort_find_dev_callback, &bus->dev);
> + } else
checkpatch.pl ?
> + node = iort_scan_node(ACPI_IORT_NODE_NAMED_COMPONENT,
> + iort_find_dev_callback, dev);
> +
> + if (!node)
> + return NULL;
> +
> + iort_dev_map_rid(node, rid, &devid, ACPI_IORT_NODE_SMMU);
> +
> + parent = iort_find_parent_node(node, ACPI_IORT_NODE_SMMU);
> +
Redundant.
> + if (!parent)
> + return NULL;
> +
> + iommu_node = iort_iommu_get_node(parent);
> + ops = iommu_node->ops;
> +
> + fwspec.fwnode = iommu_node->fwnode;
> + fwspec.param_count = 1;
> + fwspec.param[0] = devid;
> +
> + if (!ops || !ops->fw_xlate || ops->fw_xlate(dev, &fwspec))
> + return NULL;
> +
> + return ops;
> +}
> +
--
With Best Regards,
Andy Shevchenko
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