gpu: host1x: Acquire a reference to the IOVA cache

The IOVA API uses a memory cache to allocate IOVA nodes from. To make
sure that this cache is available, obtain a reference to it and release
the reference when the cache is no longer needed.

On 64-bit ARM this is hidden by the fact that the DMA mapping API gets
that reference and never releases it. On 32-bit ARM, this is papered
over by the Tegra DRM driver (the sole user of the host1x API requiring
the cache) acquiring a reference to the IOVA cache for its own purposes.
However, there may be additional users of this API in the future, so fix
this upfront to avoid surprises.

Fixes: 404bfb78daf3 ("gpu: host1x: Add IOMMU support")
Reviewed-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

1 files changed, 10 insertions, 1 deletions

diff --git a/drivers/gpu/host1x/dev.c b/drivers/gpu/host1x/dev.c
index 03db71173f5d..f1d5f76e9c33 100644
--- a/drivers/gpu/host1x/dev.c
+++ b/drivers/gpu/host1x/dev.c
@@ -223,10 +223,14 @@ static int host1x_probe(struct platform_device *pdev)
                 struct iommu_domain_geometry *geometry;
                 unsigned long order;
 
+                err = iova_cache_get();
+                if (err < 0)
+                        goto put_group;
+
                 host->domain = iommu_domain_alloc(&platform_bus_type);
                 if (!host->domain) {
                         err = -ENOMEM;
-                        goto put_group;
+                        goto put_cache;
                 }
 
                 err = iommu_attach_group(host->domain, host->group);
@@ -234,6 +238,7 @@ static int host1x_probe(struct platform_device *pdev)
                         if (err == -ENODEV) {
                                 iommu_domain_free(host->domain);
                                 host->domain = NULL;
+                                iova_cache_put();
                                 iommu_group_put(host->group);
                                 host->group = NULL;
                                 goto skip_iommu;
@@ -308,6 +313,9 @@ fail_detach_device:
 fail_free_domain:
         if (host->domain)
                 iommu_domain_free(host->domain);
+put_cache:
+        if (host->group)
+                iova_cache_put();
 put_group:
         iommu_group_put(host->group);
 
@@ -328,6 +336,7 @@ static int host1x_remove(struct platform_device *pdev)
                 put_iova_domain(&host->iova);
                 iommu_detach_group(host->domain, host->group);
                 iommu_domain_free(host->domain);
+                iova_cache_put();
                 iommu_group_put(host->group);
         }