On Wed, Oct 09, 2013 at 11:38:01PM +0100, Andreas Herrmann wrote:
> drivers/iommu/arm-smmu.c | 53
> ++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 53 insertions(+)
>
> diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
> index 478c8ad..87239e8 100644
> --- a/drivers/iommu/arm-smmu.c
> +++ b/drivers/iommu/arm-smmu.c
> @@ -46,6 +46,7 @@
> #include <linux/amba/bus.h>
>
> #include <asm/pgalloc.h>
> +#include <asm/dma-iommu.h>
>
> /* Driver options */
> #define ARM_SMMU_OPT_ISOLATE_DEVICES (1 << 0)
> @@ -1983,6 +1984,56 @@ static int arm_smmu_device_remove(struct
> platform_device *pdev)
> return 0;
> }
>
> +static int arm_smmu_device_notifier(struct notifier_block *nb,
> + unsigned long action, void *data)
> +{
> + struct device *dev = data;
> + struct dma_iommu_mapping *mapping;
> + struct arm_smmu_device *smmu;
> + void __iomem *gr0_base;
> + u32 cr0;
> + int ret;
> +
> + switch (action) {
> + case BUS_NOTIFY_BIND_DRIVER:
> +
> + arm_smmu_add_device(dev);
> + smmu = dev->archdata.iommu;
> + if (!smmu || !(smmu->options & ARM_SMMU_OPT_ISOLATE_DEVICES))
> + break;
> +
> + mapping = arm_iommu_create_mapping(&platform_bus_type,
> + 0, SZ_128M, 0);
We need to find a better way of doing this; I'm really not happy hardcoding
that size limit and hoping for the best.
> + if (IS_ERR(mapping)) {
> + ret = PTR_ERR(mapping);
> + dev_info(dev, "arm_iommu_create_mapping failed\n");
> + break;
> + }
> +
> + ret = arm_iommu_attach_device(dev, mapping);
> + if (ret < 0) {
> + dev_info(dev, "arm_iommu_attach_device failed\n");
> + arm_iommu_release_mapping(mapping);
> + }
> +
> + gr0_base = ARM_SMMU_GR0_NS(smmu);
> + cr0 = readl_relaxed(gr0_base + ARM_SMMU_GR0_sCR0);
> + cr0 |= sCR0_USFCFG;
> + writel(cr0, gr0_base + ARM_SMMU_GR0_sCR0);
Why do you need to enable this flag? If no mapping is found, that means *we*
screwed something up, so we should report that and not rely on the hardware
potentially raising a fault. I also prefer to allow passthrough for devices
that don't hit in the stream table, because it allows people to ignore the SMMU
in their DT if they want to.
Will
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