From 5a1bb638d5677053c7addcb228b56da6fccb5d68 Mon Sep 17 00:00:00 2001 From: Sricharan R Date: Mon, 10 Apr 2017 16:51:03 +0530 Subject: drivers: acpi: Handle IOMMU lookup failure with deferred probing or error This is an equivalent to the DT's handling of the iommu master's probe with deferred probing when the corrsponding iommu is not probed yet. The lack of a registered IOMMU can be caused by the lack of a driver for the IOMMU, the IOMMU device probe not having been performed yet, having been deferred, or having failed. The first case occurs when the firmware describes the bus master and IOMMU topology correctly but no device driver exists for the IOMMU yet or the device driver has not been compiled in. Return NULL, the caller will configure the device without an IOMMU. The second and third cases are handled by deferring the probe of the bus master device which will eventually get reprobed after the IOMMU. The last case is currently handled by deferring the probe of the bus master device as well. A mechanism to either configure the bus master device without an IOMMU or to fail the bus master device probe depending on whether the IOMMU is optional or mandatory would be a good enhancement. Tested-by: Hanjun Guo Reviewed-by: Robin Murphy [Lorenzo: Added fixes for dma_coherent_mask overflow, acpi_dma_configure called multiple times for same device] Signed-off-by: Lorenzo Pieralisi Signed-off-by: Sricharan R Signed-off-by: Joerg Roedel --- drivers/acpi/arm64/iort.c | 33 ++++++++++++++++++++++++++++++++- 1 file changed, 32 insertions(+), 1 deletion(-) (limited to 'drivers/acpi/arm64') diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c index 3dd9ec372dae..e323ece0314d 100644 --- a/drivers/acpi/arm64/iort.c +++ b/drivers/acpi/arm64/iort.c @@ -543,6 +543,14 @@ static const struct iommu_ops *iort_iommu_xlate(struct device *dev, const struct iommu_ops *ops = NULL; int ret = -ENODEV; struct fwnode_handle *iort_fwnode; + struct iommu_fwspec *fwspec = dev->iommu_fwspec; + + /* + * If we already translated the fwspec there + * is nothing left to do, return the iommu_ops. + */ + if (fwspec && fwspec->ops) + return fwspec->ops; if (node) { iort_fwnode = iort_get_fwnode(node); @@ -550,8 +558,17 @@ static const struct iommu_ops *iort_iommu_xlate(struct device *dev, return NULL; ops = iommu_ops_from_fwnode(iort_fwnode); + /* + * If the ops look-up fails, this means that either + * the SMMU drivers have not been probed yet or that + * the SMMU drivers are not built in the kernel; + * Depending on whether the SMMU drivers are built-in + * in the kernel or not, defer the IOMMU configuration + * or just abort it. + */ if (!ops) - return NULL; + return iort_iommu_driver_enabled(node->type) ? + ERR_PTR(-EPROBE_DEFER) : NULL; ret = arm_smmu_iort_xlate(dev, streamid, iort_fwnode, ops); } @@ -625,12 +642,26 @@ const struct iommu_ops *iort_iommu_configure(struct device *dev) while (parent) { ops = iort_iommu_xlate(dev, parent, streamid); + if (IS_ERR_OR_NULL(ops)) + return ops; parent = iort_node_get_id(node, &streamid, IORT_IOMMU_TYPE, i++); } } + /* + * If we have reason to believe the IOMMU driver missed the initial + * add_device callback for dev, replay it to get things in order. + */ + if (!IS_ERR_OR_NULL(ops) && ops->add_device && + dev->bus && !dev->iommu_group) { + int err = ops->add_device(dev); + + if (err) + ops = ERR_PTR(err); + } + return ops; } -- cgit