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 <[email protected]>
Reviewed-by: Ray Jui <[email protected]>
Reviewed-by: Scott Branden <[email protected]>
---
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,
