From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Sricharan R To: robin.murphy@arm.com, will.deacon@arm.com, joro@8bytes.org, lorenzo.pieralisi@arm.com, iommu@lists.linux-foundation.org, linux-arm-kernel@lists.infradead.org, linux-arm-msm@vger.kernel.org, m.szyprowski@samsung.com, bhelgaas@google.com, linux-pci@vger.kernel.org, linux-acpi@vger.kernel.org, tn@semihalf.com, hanjun.guo@linaro.org, okaya@codeaurora.org Cc: sricharan@codeaurora.org Subject: [PATCH V8 07/11] iommu: of: Handle IOMMU lookup failure with deferred probing or error Date: Fri, 3 Feb 2017 21:18:49 +0530 Message-Id: <1486136933-20328-8-git-send-email-sricharan@codeaurora.org> In-Reply-To: <1486136933-20328-1-git-send-email-sricharan@codeaurora.org> References: <1486136933-20328-1-git-send-email-sricharan@codeaurora.org> Sender: linux-acpi-owner@vger.kernel.org List-ID: From: Laurent Pinchart 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. Tested-by: Marek Szyprowski Signed-off-by: Laurent Pichart Signed-off-by: Sricharan R --- [*] Fixed minor comment from Bjorn for removing the pci.h header inclusion in of_iommu.c drivers/base/dma-mapping.c | 5 +++-- drivers/iommu/of_iommu.c | 4 ++-- drivers/of/device.c | 7 ++++++- include/linux/of_device.h | 9 ++++++--- 4 files changed, 17 insertions(+), 8 deletions(-) diff --git a/drivers/base/dma-mapping.c b/drivers/base/dma-mapping.c index 449b948..82bd45c 100644 --- a/drivers/base/dma-mapping.c +++ b/drivers/base/dma-mapping.c @@ -353,6 +353,7 @@ int dma_configure(struct device *dev) { struct device *bridge = NULL, *dma_dev = dev; enum dev_dma_attr attr; + int ret = 0; if (dev_is_pci(dev)) { bridge = pci_get_host_bridge_device(to_pci_dev(dev)); @@ -363,7 +364,7 @@ int dma_configure(struct device *dev) } if (dma_dev->of_node) { - of_dma_configure(dev, dma_dev->of_node); + ret = of_dma_configure(dev, dma_dev->of_node); } else if (has_acpi_companion(dma_dev)) { attr = acpi_get_dma_attr(to_acpi_device_node(dma_dev->fwnode)); if (attr != DEV_DMA_NOT_SUPPORTED) @@ -373,7 +374,7 @@ int dma_configure(struct device *dev) if (bridge) pci_put_host_bridge_device(bridge); - return 0; + return ret; } void dma_deconfigure(struct device *dev) diff --git a/drivers/iommu/of_iommu.c b/drivers/iommu/of_iommu.c index 1f92d98..2d04663 100644 --- a/drivers/iommu/of_iommu.c +++ b/drivers/iommu/of_iommu.c @@ -236,7 +236,7 @@ const struct iommu_ops *of_iommu_configure(struct device *dev, ops = ERR_PTR(err); } - return IS_ERR(ops) ? NULL : ops; + return ops; } static int __init of_iommu_init(void) @@ -247,7 +247,7 @@ 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 c17c19d..ba51ca6 100644 --- a/drivers/of/device.c +++ b/drivers/of/device.c @@ -82,7 +82,7 @@ int of_device_add(struct platform_device *ofdev) * can use a platform bus notifier and handle BUS_NOTIFY_ADD_DEVICE events * to fix up DMA configuration. */ -void of_dma_configure(struct device *dev, struct device_node *np) +int of_dma_configure(struct device *dev, struct device_node *np) { u64 dma_addr, paddr, size; int ret; @@ -129,10 +129,15 @@ void of_dma_configure(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 "); arch_setup_dma_ops(dev, dma_addr, size, iommu, coherent); + + return 0; } EXPORT_SYMBOL_GPL(of_dma_configure); diff --git a/include/linux/of_device.h b/include/linux/of_device.h index 3cb2288..9499861 100644 --- a/include/linux/of_device.h +++ b/include/linux/of_device.h @@ -56,7 +56,7 @@ static inline struct device_node *of_cpu_device_node_get(int cpu) return of_node_get(cpu_dev->of_node); } -void of_dma_configure(struct device *dev, struct device_node *np); +int of_dma_configure(struct device *dev, struct device_node *np); void of_dma_deconfigure(struct device *dev); #else /* CONFIG_OF */ @@ -105,8 +105,11 @@ static inline struct device_node *of_cpu_device_node_get(int cpu) { return NULL; } -static inline void of_dma_configure(struct device *dev, struct device_node *np) -{} + +static inline int of_dma_configure(struct device *dev, struct device_node *np) +{ + return 0; +} static inline void of_dma_deconfigure(struct device *dev) {} #endif /* CONFIG_OF */ -- QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation