[RFC PATCH 09/11] drivers: acpi: implement acpi_dma_configure
From: Andy Shevchenko <hidden>
Date: 2016-04-21 22:45:41
Also in:
linux-acpi, linux-iommu, linux-pci, lkml
On Thu, Apr 14, 2016 at 8:25 PM, Lorenzo Pieralisi [off-list ref] 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.
quoted hunk ↗ jump to hunk
--- 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