[PATCH v6 16/21] iommu/tegra: gart: Allow only one active domain at a time

Dmitry Osipenko
2018-12-09T20:29:45Z

GART has a single address space that is shared by all devices, hence only
one domain could be active at a time.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Acked-by: Thierry Reding <treding@nvidia.com>
---
drivers/iommu/tegra-gart.c | 9 +++++++++
1 file changed, 9 insertions(+)

diff --git a/drivers/iommu/tegra-gart.c b/drivers/iommu/tegra-gart.c
index bb5303b06845..1be595d15e7e 100644
--- a/drivers/iommu/tegra-gart.c
+++ b/drivers/iommu/tegra-gart.c
@@ -57,6 +57,7 @@ struct gart_device {
spinlock_t pte_lock; /* for pagetable */
struct list_head client;
spinlock_t client_lock; /* for client list */
+ struct iommu_domain *active_domain; /* current active domain */
struct device *dev;

struct iommu_device iommu; /* IOMMU Core handle */
@@ -186,6 +187,12 @@ static int gart_iommu_attach_dev(struct iommu_domain *domain,
goto fail;
}
}
+ if (gart->active_domain && gart->active_domain != domain) {
+ dev_err(gart->dev, "Only one domain can be active at a time\n");
+ err = -EINVAL;
+ goto fail;
+ }
+ gart->active_domain = domain;
list_add(&client->list, &gart->client);
spin_unlock(&gart->client_lock);
dev_dbg(gart->dev, "Attached %s\n", dev_name(dev));
@@ -208,6 +215,8 @@ static void __gart_iommu_detach_dev(struct iommu_domain *domain,
if (c->dev == dev) {
list_del(&c->list);
devm_kfree(gart->dev, c);
+ if (list_empty(&gart->client))
+ gart->active_domain = NULL;
dev_dbg(gart->dev, "Detached %s\n", dev_name(dev));
return;
}
--
2.19.1