[PATCH v6 10/25] iommu/exynos: Implement an IDENTITY domain

Jason Gunthorpe
2023-08-03T00:30:45Z

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.

Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Acked-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
---
drivers/iommu/exynos-iommu.c | 66 +++++++++++++++++-------------------
1 file changed, 32 insertions(+), 34 deletions(-)

diff --git a/drivers/iommu/exynos-iommu.c b/drivers/iommu/exynos-iommu.c
index c275fe71c4db32..5e12b85dfe8705 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 +981,20 @@ 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->domain == identity_domain)
+ return 0;
+
+ domain = to_exynos_domain(owner->domain);
+ pagetable = virt_to_phys(domain->pgtable);

mutex_lock(&owner->rpm_lock);

@@ -1009,15 +1013,25 @@ static void exynos_iommu_detach_device(struct iommu_domain *iommu_domain,
list_del_init(&data->domain_node);
spin_unlock(&data->lock);
}
- 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__,
- &pagetable);
+ dev_dbg(dev, "%s: Restored IOMMU to IDENTITY from pgtable %pa\n",
+ __func__, &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 +1040,11 @@ 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 +1420,12 @@ 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 +1456,7 @@ static int exynos_iommu_of_xlate(struct device *dev,

INIT_LIST_HEAD(&owner->controllers);
mutex_init(&owner->rpm_lock);
+ owner->domain = &exynos_identity_domain;
dev_iommu_priv_set(dev, owner);
}

@@ -1471,11 +1471,9 @@ 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,
--
2.41.0