iommu/tegra: gart: Allow only one active domain at a time

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>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

diff --git a/drivers/iommu/tegra-gart.c b/drivers/iommu/tegra-gart.c
index 7fdd8b12efd5db671213034c46b34f4f01096f10..71ff22be956017a7afeead15a616a1374b94d91b 100644 (file)
--- 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;
                }