[+hanjun, tomasz, sinan]
It is quite a key patchset, I would be glad if they can test on their
respective platforms with IORT.
On Mon, Jan 23, 2017 at 09:48:10PM +0530, Sricharan R wrote:
> 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.
>
> Signed-off-by: Sricharan R <sricharan@xxxxxxxxxxxxxx>
> ---
> drivers/acpi/arm64/iort.c | 25 ++++++++++++++++++++++++-
> drivers/acpi/scan.c | 7 +++++--
> drivers/base/dma-mapping.c | 2 +-
> include/acpi/acpi_bus.h | 2 +-
> include/linux/acpi.h | 7 +++++--
> 5 files changed, 36 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c
> index bf0ed09..d01bae8 100644
> --- a/drivers/acpi/arm64/iort.c
> +++ b/drivers/acpi/arm64/iort.c
> @@ -550,8 +550,17 @@ static const struct iommu_ops *iort_iommu_xlate(struct device *dev,
> return NULL;
>
> ops = iommu_get_instance(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 +634,26 @@ 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);
> + }
I think there is nothing ACPI specific in this add_device() replay
path, so there is room for further DT/ACPI consolidation here.
Without any further ado:
Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx>
> +
> return ops;
> }
>
> diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
> index 1926918..823b005 100644
> --- a/drivers/acpi/scan.c
> +++ b/drivers/acpi/scan.c
> @@ -1373,20 +1373,23 @@ enum dev_dma_attr acpi_get_dma_attr(struct acpi_device *adev)
> * @dev: The pointer to the device
> * @attr: device dma attributes
> */
> -void acpi_dma_configure(struct device *dev, enum dev_dma_attr attr)
> +int acpi_dma_configure(struct device *dev, enum dev_dma_attr attr)
> {
> const struct iommu_ops *iommu;
>
> iort_set_dma_mask(dev);
>
> iommu = iort_iommu_configure(dev);
> -
> + if (IS_ERR(iommu))
> + return PTR_ERR(iommu);
> /*
> * Assume dma valid range starts at 0 and covers the whole
> * coherent_dma_mask.
> */
> arch_setup_dma_ops(dev, 0, dev->coherent_dma_mask + 1, iommu,
> attr == DEV_DMA_COHERENT);
> +
> + return 0;
> }
> EXPORT_SYMBOL_GPL(acpi_dma_configure);
>
> diff --git a/drivers/base/dma-mapping.c b/drivers/base/dma-mapping.c
> index 82bd45c..755a2b5 100644
> --- a/drivers/base/dma-mapping.c
> +++ b/drivers/base/dma-mapping.c
> @@ -368,7 +368,7 @@ int dma_configure(struct device *dev)
> } 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)
> - acpi_dma_configure(dev, attr);
> + ret = acpi_dma_configure(dev, attr);
> }
>
> if (bridge)
> diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
> index 4242c31..9aa762fe 100644
> --- a/include/acpi/acpi_bus.h
> +++ b/include/acpi/acpi_bus.h
> @@ -573,7 +573,7 @@ struct acpi_pci_root {
>
> bool acpi_dma_supported(struct acpi_device *adev);
> enum dev_dma_attr acpi_get_dma_attr(struct acpi_device *adev);
> -void acpi_dma_configure(struct device *dev, enum dev_dma_attr attr);
> +int acpi_dma_configure(struct device *dev, enum dev_dma_attr attr);
> void acpi_dma_deconfigure(struct device *dev);
>
> struct acpi_device *acpi_find_child_device(struct acpi_device *parent,
> diff --git a/include/linux/acpi.h b/include/linux/acpi.h
> index 5b36974..8b958b6 100644
> --- a/include/linux/acpi.h
> +++ b/include/linux/acpi.h
> @@ -764,8 +764,11 @@ static inline enum dev_dma_attr acpi_get_dma_attr(struct acpi_device *adev)
> return DEV_DMA_NOT_SUPPORTED;
> }
>
> -static inline void acpi_dma_configure(struct device *dev,
> - enum dev_dma_attr attr) { }
> +static inline int acpi_dma_configure(struct device *dev,
> + enum dev_dma_attr attr)
> +{
> + return 0;
> +}
>
> static inline void acpi_dma_deconfigure(struct device *dev) { }
>
> --
> QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation
>
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