From: Thierry Reding <treding@nvidia.com>
Date: Mon, 19 Jan 2015 15:15:04 +0000 (+0100)
Subject: drm/tegra: gem: Take into account IOMMU aperture
X-Git-Tag: v4.14-rc1~5088^2~13^2~2
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=4553f733c68b66ef49f838aa24470d58caf76ff5;p=platform%2Fkernel%2Flinux-rpi.git

drm/tegra: gem: Take into account IOMMU aperture

The IOMMU may not always be able to address 2 GiB of memory. On Tegra20,
the GART supports 32 MiB starting at 0x58000000. Also the aperture on
Tegra30 and later is in fact the full 4 GiB, rather than just 2 GiB as
currently assumed.

Signed-off-by: Thierry Reding <treding@nvidia.com>
---

diff --git a/drivers/gpu/drm/tegra/drm.c b/drivers/gpu/drm/tegra/drm.c
index 1833abd..1062084 100644
--- a/drivers/gpu/drm/tegra/drm.c
+++ b/drivers/gpu/drm/tegra/drm.c
@@ -124,14 +124,22 @@ static int tegra_drm_load(struct drm_device *drm, unsigned long flags)
 		return -ENOMEM;
 
 	if (iommu_present(&platform_bus_type)) {
+		struct iommu_domain_geometry *geometry;
+		u64 start, end;
+
 		tegra->domain = iommu_domain_alloc(&platform_bus_type);
 		if (!tegra->domain) {
 			err = -ENOMEM;
 			goto free;
 		}
 
-		DRM_DEBUG("IOMMU context initialized\n");
-		drm_mm_init(&tegra->mm, 0, SZ_2G);
+		geometry = &tegra->domain->geometry;
+		start = geometry->aperture_start;
+		end = geometry->aperture_end;
+
+		DRM_DEBUG("IOMMU context initialized (aperture: %#llx-%#llx)\n",
+			  start, end);
+		drm_mm_init(&tegra->mm, start, end - start + 1);
 	}
 
 	mutex_init(&tegra->clients_lock);