From 3cf485540e7b8550936ce3602edf2f58e4007304 Mon Sep 17 00:00:00 2001 From: Jean-Philippe Brucker Date: Fri, 18 Jun 2021 17:20:58 +0200 Subject: ACPI: Add driver for the VIOT table The ACPI Virtual I/O Translation Table describes topology of para-virtual platforms, similarly to vendor tables DMAR, IVRS and IORT. For now it describes the relation between virtio-iommu and the endpoints it manages. Three steps are needed to configure DMA of endpoints: (1) acpi_viot_init(): parse the VIOT table, find or create the fwnode associated to each vIOMMU device. This needs to happen after acpi_scan_init(), because it relies on the struct device and their fwnode to be available. (2) When probing the vIOMMU device, the driver registers its IOMMU ops within the IOMMU subsystem. This step doesn't require any intervention from the VIOT driver. (3) viot_iommu_configure(): before binding the endpoint to a driver, find the associated IOMMU ops. Register them, along with the endpoint ID, into the device's iommu_fwspec. If step (3) happens before step (2), it is deferred until the IOMMU is initialized, then retried. Tested-by: Eric Auger Reviewed-by: Eric Auger Signed-off-by: Jean-Philippe Brucker Acked-by: Rafael J. Wysocki Link: https://lore.kernel.org/r/20210618152059.1194210-4-jean-philippe@linaro.org Signed-off-by: Joerg Roedel --- drivers/acpi/scan.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'drivers/acpi/scan.c') diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c index 2a2e690040e9..3e2bb04ab528 100644 --- a/drivers/acpi/scan.c +++ b/drivers/acpi/scan.c @@ -9,6 +9,7 @@ #include #include #include +#include #include #include #include @@ -1556,6 +1557,8 @@ static const struct iommu_ops *acpi_iommu_configure_id(struct device *dev, return ops; err = iort_iommu_configure_id(dev, id_in); + if (err && err != -EPROBE_DEFER) + err = viot_iommu_configure(dev); /* * If we have reason to believe the IOMMU driver missed the initial -- cgit v1.2.3