Messages in this thread | | | Subject | Re: [RFC PATCH 4/6] iommu/arm-smmu: Add support for IOMMU_DOMAIN_DMA in SMMUv1/SMMUv2 driver | From | Robin Murphy <> | Date | Thu, 28 Jan 2016 17:28:30 +0000 |
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On 27/01/16 05:21, Anup Patel wrote: > To allow use of large memory (> 4Gb) with 32bit devices we need to use > some kind of iommu for such 32bit devices. > > This patch extends SMMUv1/SMMUv2 driver to support DMA domains which > in-turn will allows us to use iommu based DMA mappings for 32bit devices. > > Signed-off-by: Anup Patel <anup.patel@broadcom.com> > Reviewed-by: Ray Jui <rjui@broadcom.com> > Reviewed-by: Scott Branden <sbranden@broadcom.com> > --- > drivers/iommu/arm-smmu.c | 21 ++++++++++++++++++++- > 1 file changed, 20 insertions(+), 1 deletion(-) > > diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c > index 9bdf6b2..43424fe 100644 > --- a/drivers/iommu/arm-smmu.c > +++ b/drivers/iommu/arm-smmu.c > @@ -29,6 +29,7 @@ > #define pr_fmt(fmt) "arm-smmu: " fmt > > #include <linux/delay.h> > +#include <linux/dma-iommu.h> > #include <linux/dma-mapping.h> > #include <linux/err.h> > #include <linux/interrupt.h> > @@ -967,7 +968,7 @@ static struct iommu_domain *arm_smmu_domain_alloc(unsigned type) > { > struct arm_smmu_domain *smmu_domain; > > - if (type != IOMMU_DOMAIN_UNMANAGED) > + if (type != IOMMU_DOMAIN_UNMANAGED && type != IOMMU_DOMAIN_DMA) > return NULL; > /* > * Allocate the domain and initialise some of its data structures. > @@ -978,6 +979,12 @@ static struct iommu_domain *arm_smmu_domain_alloc(unsigned type) > if (!smmu_domain) > return NULL; > > + if (type == IOMMU_DOMAIN_DMA && > + iommu_get_dma_cookie(&smmu_domain->domain)) { > + kfree(smmu_domain); > + return NULL; > + } > + > mutex_init(&smmu_domain->init_mutex); > spin_lock_init(&smmu_domain->pgtbl_lock); > > @@ -992,6 +999,7 @@ static void arm_smmu_domain_free(struct iommu_domain *domain) > * Free the domain resources. We assume that all devices have > * already been detached. > */ > + iommu_put_dma_cookie(domain); > arm_smmu_destroy_domain_context(domain); > kfree(smmu_domain); > } > @@ -1361,6 +1369,16 @@ static int arm_smmu_init_platform_device(struct device *dev, > return 0; > } > > +int arm_smmu_of_xlate(struct device *dev, struct of_phandle_args *args) > +{ > + /* > + * Nothing to do here because SMMU is already aware of all > + * MMU masters and their stream IDs using mmu-master attibute > + * SMMU DT node. > + */
...but on the same hand this will also never get called if there's no "iommus" property on the master. Maintaining support for existing users of the "mmu-masters" binding is one thing (namely the thing that's been slowing down my efforts to clean up the really hacky generic binding support I did all the DMA stuff with), but having _both_ bindings in a single DT is something I don't think anybody wants to see - is that how you've tested this?
Robin.
> + return 0; > +} > + > static int arm_smmu_add_device(struct device *dev) > { > struct iommu_group *group; > @@ -1458,6 +1476,7 @@ static struct iommu_ops arm_smmu_ops = { > .unmap = arm_smmu_unmap, > .map_sg = default_iommu_map_sg, > .iova_to_phys = arm_smmu_iova_to_phys, > + .of_xlate = arm_smmu_of_xlate, > .add_device = arm_smmu_add_device, > .remove_device = arm_smmu_remove_device, > .device_group = arm_smmu_device_group, >
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