On 2023-05-01 19:02, Jason Gunthorpe wrote:
What exynos calls exynos_iommu_detach_device is actually putting the iommu
into identity mode.
Move to the new core support for ARM_DMA_USE_IOMMU by defining
ops->identity_domain.
Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxx>
---
drivers/iommu/exynos-iommu.c | 64 ++++++++++++++++++------------------
1 file changed, 32 insertions(+), 32 deletions(-)
diff --git a/drivers/iommu/exynos-iommu.c b/drivers/iommu/exynos-iommu.c
index c275fe71c4db32..6ff7901103948a 100644
--- a/drivers/iommu/exynos-iommu.c
+++ b/drivers/iommu/exynos-iommu.c
@@ -24,6 +24,7 @@
typedef u32 sysmmu_iova_t;
typedef u32 sysmmu_pte_t;
+static struct iommu_domain exynos_identity_domain;
/* We do not consider super section mapping (16MB) */
#define SECT_ORDER 20
@@ -829,7 +830,7 @@ static int __maybe_unused exynos_sysmmu_suspend(struct device *dev)
struct exynos_iommu_owner *owner = dev_iommu_priv_get(master);
mutex_lock(&owner->rpm_lock);
- if (data->domain) {
+ if (&data->domain->domain != &exynos_identity_domain) {
dev_dbg(data->sysmmu, "saving state\n");
__sysmmu_disable(data);
}
@@ -847,7 +848,7 @@ static int __maybe_unused exynos_sysmmu_resume(struct device *dev)
struct exynos_iommu_owner *owner = dev_iommu_priv_get(master);
mutex_lock(&owner->rpm_lock);
- if (data->domain) {
+ if (&data->domain->domain != &exynos_identity_domain) {
dev_dbg(data->sysmmu, "restoring state\n");
__sysmmu_enable(data);
}
@@ -980,17 +981,22 @@ static void exynos_iommu_domain_free(struct iommu_domain *iommu_domain)
kfree(domain);
}
-static void exynos_iommu_detach_device(struct iommu_domain *iommu_domain,
- struct device *dev)
+static int exynos_iommu_identity_attach(struct iommu_domain *identity_domain,
+ struct device *dev)
{
- struct exynos_iommu_domain *domain = to_exynos_domain(iommu_domain);
struct exynos_iommu_owner *owner = dev_iommu_priv_get(dev);
- phys_addr_t pagetable = virt_to_phys(domain->pgtable);
+ struct exynos_iommu_domain *domain;
+ phys_addr_t pagetable;
struct sysmmu_drvdata *data, *next;
unsigned long flags;
- if (!has_sysmmu(dev) || owner->domain != iommu_domain)
- return;
+ if (!owner)
+ return -ENODEV;
That can't be true - devices can't be attached without having already
dereferenced their group, which means they've been through probe_device
successfully.
+ if (owner->domain == identity_domain)
+ return 0;
+
+ domain = to_exynos_domain(owner->domain);
+ pagetable = virt_to_phys(domain->pgtable);
Identity domains by definition shouldn't have a pagetable? I don't think
virt_to_phys(NULL) can be assumed to be valid or safe in general.
mutex_lock(&owner->rpm_lock);
@@ -1009,15 +1015,25 @@ static void exynos_iommu_detach_device(struct iommu_domain *iommu_domain,
list_del_init(&data->domain_node);
spin_unlock(&data->lock);
}
This iterates the whole domain->clients list, which may include other
devices from other groups belonging to other IOMMU instances. I think
that's technically an issue already given that we support cross-instance
domain attach here, which the DRM drivers rely on. I can't quite work
out off-hand if this is liable to make it any worse or not :/
- owner->domain = NULL;
+ owner->domain = identity_domain;
spin_unlock_irqrestore(&domain->lock, flags);
mutex_unlock(&owner->rpm_lock);
dev_dbg(dev, "%s: Detached IOMMU with pgtable %pa\n", __func__,
This no longer makes much sense.
&pagetable);
+ return 0;
}
+static struct iommu_domain_ops exynos_identity_ops = {
+ .attach_dev = exynos_iommu_identity_attach,
+};
+
+static struct iommu_domain exynos_identity_domain = {
+ .type = IOMMU_DOMAIN_IDENTITY,
+ .ops = &exynos_identity_ops,
+};
+
static int exynos_iommu_attach_device(struct iommu_domain *iommu_domain,
struct device *dev)
{
@@ -1026,12 +1042,11 @@ static int exynos_iommu_attach_device(struct iommu_domain *iommu_domain,
struct sysmmu_drvdata *data;
phys_addr_t pagetable = virt_to_phys(domain->pgtable);
unsigned long flags;
+ int err;
- if (!has_sysmmu(dev))
- return -ENODEV;
-
- if (owner->domain)
- exynos_iommu_detach_device(owner->domain, dev);
+ err = exynos_iommu_identity_attach(&exynos_identity_domain, dev);
+ if (err)
+ return err;
mutex_lock(&owner->rpm_lock);
@@ -1407,26 +1422,12 @@ static struct iommu_device *exynos_iommu_probe_device(struct device *dev)
return &data->iommu;
}
-static void exynos_iommu_set_platform_dma(struct device *dev)
-{
- struct exynos_iommu_owner *owner = dev_iommu_priv_get(dev);
-
- if (owner->domain) {
- struct iommu_group *group = iommu_group_get(dev);
-
- if (group) {
- exynos_iommu_detach_device(owner->domain, dev);
- iommu_group_put(group);
- }
- }
-}
-
static void exynos_iommu_release_device(struct device *dev)
{
struct exynos_iommu_owner *owner = dev_iommu_priv_get(dev);
struct sysmmu_drvdata *data;
- exynos_iommu_set_platform_dma(dev);
+ WARN_ON(exynos_iommu_identity_attach(&exynos_identity_domain, dev));
list_for_each_entry(data, &owner->controllers, owner_node)
device_link_del(data->link);
@@ -1457,6 +1458,7 @@ static int exynos_iommu_of_xlate(struct device *dev,
INIT_LIST_HEAD(&owner->controllers);
mutex_init(&owner->rpm_lock);
+ owner->domain = &exynos_identity_domain;
I think strictly this would be more of a probe_device thing than an
of_xlate thing, but it's not super-important.
Thanks,
Robin.
dev_iommu_priv_set(dev, owner);
}
@@ -1471,11 +1473,9 @@ static int exynos_iommu_of_xlate(struct device *dev,
}
static const struct iommu_ops exynos_iommu_ops = {
+ .identity_domain = &exynos_identity_domain,
.domain_alloc = exynos_iommu_domain_alloc,
.device_group = generic_device_group,
-#ifdef CONFIG_ARM
- .set_platform_dma_ops = exynos_iommu_set_platform_dma,
-#endif
.probe_device = exynos_iommu_probe_device,
.release_device = exynos_iommu_release_device,
.pgsize_bitmap = SECT_SIZE | LPAGE_SIZE | SPAGE_SIZE,
