On Tue, Mar 21, 2023 at 04:43:42PM +0100, Marek Szyprowski wrote:
>
> On 21.03.2023 15:41, Jason Gunthorpe wrote:
> > On Thu, Mar 16, 2023 at 12:25:14AM +0100, Marek Szyprowski wrote:
> >> There are some subtle differences between release_device() and
> >> set_platform_dma_ops() callbacks, so separate those two callbacks. Device
> >> links should be removed only in release_device(), because they were
> >> created in probe_device() on purpose and they are needed for proper
> >> Exynos IOMMU driver operation. While fixing this, remove the conditional
> >> code as it is not really needed.
> >>
> >> Reported-by: Jason Gunthorpe <jgg@xxxxxxxx>
> >> Fixes: 189d496b48b1 ("iommu/exynos: Add missing set_platform_dma_ops callback")
> >> Signed-off-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
> >> ---
> >> v2:
> >> - keep set_platform_dma_ops only on ARM 32bit
> >>
> >> Some more background why set_platform_dma_ops is needed on ARM 32bit is
> >> available here:
> >> https://lore.kernel.org/all/9a12fcac-c347-5d81-acef-1124c50d0c37@xxxxxxx/
> >> ---
> >> drivers/iommu/exynos-iommu.c | 17 ++++++++++-------
> >> 1 file changed, 10 insertions(+), 7 deletions(-)
> > It seems OK, but do you know what state the device is left in after
> > exynos_iommu_detach_device ? Ie is it blocking or identity?
>
> identity
Can you do this cleanup like this instead?
Jason
diff --git a/drivers/iommu/exynos-iommu.c b/drivers/iommu/exynos-iommu.c
index 483aaaeb6daeac..2c2b5cba191459 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
@@ -900,6 +901,9 @@ static struct iommu_domain *exynos_iommu_domain_alloc(unsigned type)
dma_addr_t handle;
int i;
+ if (type == IOMMU_DOMAIN_IDENTITY)
+ return &exynos_identity_domain;
+
/* Check if correct PTE offsets are initialized */
BUG_ON(PG_ENT_SHIFT < 0 || !dma_dev);
@@ -988,17 +992,22 @@ 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;
+ if (owner->domain == identity_domain)
+ return 0;
+
+ domain = to_exynos_domain(owner->domain);
+ pagetable = virt_to_phys(domain->pgtable);
mutex_lock(&owner->rpm_lock);
@@ -1017,15 +1026,32 @@ 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);
+ 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,
+};
+
+#ifdef CONFIG_ARM
+static void exynos_iommu_set_platform_dma(struct device *dev)
+{
+ WARN_ON(exynos_iommu_identity_attach(&exynos_identity_domain, dev));
+}
+#endif
+
static int exynos_iommu_attach_device(struct iommu_domain *iommu_domain,
struct device *dev)
{
@@ -1034,12 +1060,11 @@ 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);
@@ -1420,18 +1445,7 @@ static void exynos_iommu_release_device(struct device *dev)
struct exynos_iommu_owner *owner = dev_iommu_priv_get(dev);
struct sysmmu_drvdata *data;
- if (owner->domain) {
- struct iommu_group *group = iommu_group_get(dev);
-
- if (group) {
-#ifndef CONFIG_ARM
- WARN_ON(owner->domain !=
- iommu_group_default_domain(group));
-#endif
- exynos_iommu_detach_device(owner->domain, dev);
- iommu_group_put(group);
- }
- }
+ WARN_ON(exynos_iommu_identity_attach(&exynos_identity_domain, dev));
list_for_each_entry(data, &owner->controllers, owner_node)
device_link_del(data->link);
@@ -1462,6 +1476,7 @@ 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);
}
@@ -1479,7 +1494,7 @@ static const struct iommu_ops exynos_iommu_ops = {
.domain_alloc = exynos_iommu_domain_alloc,
.device_group = generic_device_group,
#ifdef CONFIG_ARM
- .set_platform_dma_ops = exynos_iommu_release_device,
+ .set_platform_dma_ops = exynos_iommu_set_platform_dma,
#endif
.probe_device = exynos_iommu_probe_device,
.release_device = exynos_iommu_release_device,
