author Laurent Pinchart 2015-05-15 02:00:09 +0300 committer John Stultz 2017-05-12 12:39:38 -0700 commit c0648aa6e6063285cec2a15fecd360a3b4394af4 (patch) tree 0f23e82630929c7307560803faa4bf9b489ddd52 parent 4d4d7186492648fe2517178b983fcd5a55e3d575 (diff) download flo-c0648aa6e6063285cec2a15fecd360a3b4394af4.tar.gz iommu: of: Handle IOMMU lookup failure with deferred probing or error Failures to look up an IOMMU when parsing the DT iommus property need to be handled separately from the .of_xlate() failures to support deferred probing. 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 device tree 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. Signed-off-by: Laurent Pinchart Diffstat -rw-r--r-- drivers/iommu/of_iommu.c 18 -rw-r--r-- drivers/of/device.c 2 2 files changed, 16 insertions, 4 deletions diff --git a/drivers/iommu/of_iommu.c b/drivers/iommu/of_iommu.c index 2683e9f..b171b2c 100644 --- a/drivers/iommu/of_iommu.c +++ b/drivers/iommu/of_iommu.c @@ -159,10 +159,20 @@ const struct iommu_ops *of_iommu_configure(struct device *dev, np = iommu_spec.np; ops = iommu_ops_from_fwnode(&np->fwnode); - if (!ops || !ops->of_xlate || + if (!ops) { + const struct of_device_id *oid; + + oid = of_match_node(&__iommu_of_table, np); + ops = oid ? ERR_PTR(-EPROBE_DEFER) : NULL; + goto err_put_node; + } + + if (!ops->of_xlate || iommu_fwspec_init(dev, &np->fwnode, ops) || - ops->of_xlate(dev, &iommu_spec)) + ops->of_xlate(dev, &iommu_spec)) { + ops = NULL; goto err_put_node; + } of_node_put(np); idx++; @@ -172,7 +182,7 @@ const struct iommu_ops *of_iommu_configure(struct device *dev, err_put_node: of_node_put(np); - return NULL; + return ops; } static int __init of_iommu_init(void) @@ -183,7 +193,7 @@ static int __init of_iommu_init(void) for_each_matching_node_and_match(np, matches, &match) { const of_iommu_init_fn init_fn = match->data; - if (init_fn(np)) + if (init_fn && init_fn(np)) pr_err("Failed to initialise IOMMU %s\n", of_node_full_name(np)); } diff --git a/drivers/of/device.c b/drivers/of/device.c index d73bfa19..22365aa 100644 --- a/drivers/of/device.c +++ b/drivers/of/device.c @@ -165,6 +165,8 @@ int of_dma_configure_ops(struct device *dev, struct device_node *np) coherent ? " " : " not "); iommu = of_iommu_configure(dev, np); + if (IS_ERR(iommu)) + return PTR_ERR(iommu); dev_dbg(dev, "device is%sbehind an iommu\n", iommu ? " " : " not ");