Hi Bjorn,
On 15/04/16 17:14, Bjorn Helgaas wrote:
On Thu, Apr 14, 2016 at 06:25:41PM +0100, Lorenzo Pieralisi 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.
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx>
Cc: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
Cc: Robin Murphy <robin.murphy@xxxxxxx>
Cc: Tomasz Nowicki <tn@xxxxxxxxxxxx>
Cc: Joerg Roedel <joro@xxxxxxxxxx>
Cc: "Rafael J. Wysocki" <rjw@xxxxxxxxxxxxx>
There's only a tiny PCI change in this series, so I assume somebody
else will merge all this. Here's my ack for the PCI part:
Acked-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx> # for drivers/pci/probe.c change
One question on use of pci_for_each_dma_alias() below.
+static int __get_pci_rid(struct pci_dev *pdev, u16 alias, void *data)
+{
+ u32 *rid = data;
+
+ *rid = alias;
+ return 0;
+}
+
+/**
+ * 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);
You end up with only the last DMA alias in "rid". Is it really true
that you only need to call iort_dev_map_rid() for one of the aliases?
Indeed - all we care about is what things look like by the time they
come out of the root complex on their way to the the IOMMU, so whatever
intermediate aliasing _within_ the PCI bus might happen along the way
doesn't actually matter.
Robin.
+ node = iort_scan_node(ACPI_IORT_NODE_PCI_ROOT_COMPLEX,
+ iort_find_dev_callback, &bus->dev);
+ } else
+ 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);
+
+ 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;
+}
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