From: Thierry Reding <redacted>

When an IOMMU device is available on the platform bus, allocate an IOMMU
domain and attach the display controllers to it. The display controllers
can then scan out non-contiguous buffers by mapping them through the
IOMMU.

Signed-off-by: Thierry Reding <redacted>
---
 drivers/gpu/drm/tegra/dc.c  |  21 ++++
 drivers/gpu/drm/tegra/drm.c |  17 ++++
 drivers/gpu/drm/tegra/drm.h |   3 +
 drivers/gpu/drm/tegra/fb.c  |  16 ++-
 drivers/gpu/drm/tegra/gem.c | 236 +++++++++++++++++++++++++++++++++++++++-----
 drivers/gpu/drm/tegra/gem.h |   4 +
 6 files changed, 273 insertions(+), 24 deletions(-)

diff --git a/drivers/gpu/drm/tegra/dc.c b/drivers/gpu/drm/tegra/dc.c
index afcca04f5367..0f7452d04811 100644
--- a/drivers/gpu/drm/tegra/dc.c
+++ b/drivers/gpu/drm/tegra/dc.c

@@ -9,6 +9,7 @@

 #include <linux/clk.h>
 #include <linux/debugfs.h>
+#include <linux/iommu.h>
 #include <linux/reset.h>

 #include "dc.h"

@@ -1283,8 +1284,18 @@ static int tegra_dc_init(struct host1x_client *client)
 {
        struct drm_device *drm = dev_get_drvdata(client->parent);
        struct tegra_dc *dc = host1x_client_to_dc(client);
+       struct tegra_drm *tegra = drm->dev_private;
        int err;

+       if (tegra->domain) {
+               err = iommu_attach_device(tegra->domain, dc->dev);

+               if (err < 0) {
+                       dev_err(dc->dev, "failed to attach to IOMMU: %d\n",
+                               err);
+                       return err;
+               }
+       }
+
        drm_crtc_init(drm, &dc->base, &tegra_crtc_funcs);
        drm_mode_crtc_set_gamma_size(&dc->base, 256);
        drm_crtc_helper_add(&dc->base, &tegra_crtc_helper_funcs);

@@ -1318,7 +1329,9 @@ static int tegra_dc_init(struct host1x_client *client)

 static int tegra_dc_exit(struct host1x_client *client)
 {
+       struct drm_device *drm = dev_get_drvdata(client->parent);
        struct tegra_dc *dc = host1x_client_to_dc(client);
+       struct tegra_drm *tegra = drm->dev_private;
        int err;

        devm_free_irq(dc->dev, dc->irq, dc);

@@ -1335,6 +1348,8 @@ static int tegra_dc_exit(struct host1x_client *client)
                return err;
        }

+       iommu_detach_device(tegra->domain, dc->dev);
+
        return 0;
 }

@@ -1462,6 +1477,12 @@ static int tegra_dc_probe(struct platform_device *pdev)
                return -ENXIO;
        }

+       err = iommu_attach(&pdev->dev);
+       if (err < 0) {
+               dev_err(&pdev->dev, "failed to attach to IOMMU: %d\n", err);
+               return err;
+       }
+
        INIT_LIST_HEAD(&dc->client.list);
        dc->client.ops = &dc_client_ops;
        dc->client.dev = &pdev->dev;

diff --git a/drivers/gpu/drm/tegra/drm.c b/drivers/gpu/drm/tegra/drm.c
index 59736bb810cd..1d2bbafad982 100644
--- a/drivers/gpu/drm/tegra/drm.c
+++ b/drivers/gpu/drm/tegra/drm.c

@@ -8,6 +8,7 @@
  */

 #include <linux/host1x.h>
+#include <linux/iommu.h>

 #include "drm.h"
 #include "gem.h"

@@ -33,6 +34,16 @@ static int tegra_drm_load(struct drm_device *drm, unsigned long flags)
        if (!tegra)
                return -ENOMEM;

+       if (iommu_present(&platform_bus_type)) {
+               tegra->domain = iommu_domain_alloc(&platform_bus_type);

+               if (IS_ERR(tegra->domain)) {
+                       kfree(tegra);
+                       return PTR_ERR(tegra->domain);
+               }
+
+               drm_mm_init(&tegra->mm, 0, SZ_2G);
+       }
+
        mutex_init(&tegra->clients_lock);
        INIT_LIST_HEAD(&tegra->clients);
        drm->dev_private = tegra;

@@ -71,6 +82,7 @@ static int tegra_drm_load(struct drm_device *drm, unsigned long flags)
 static int tegra_drm_unload(struct drm_device *drm)
 {
        struct host1x_device *device = to_host1x_device(drm->dev);
+       struct tegra_drm *tegra = drm->dev_private;
        int err;

        drm_kms_helper_poll_fini(drm);

@@ -82,6 +94,11 @@ static int tegra_drm_unload(struct drm_device *drm)
        if (err < 0)
                return err;

+       if (tegra->domain) {
+               iommu_domain_free(tegra->domain);
+               drm_mm_takedown(&tegra->mm);
+       }
+
        return 0;
 }

diff --git a/drivers/gpu/drm/tegra/drm.h b/drivers/gpu/drm/tegra/drm.h
index 96d754e7b3eb..a07c796b7edc 100644
--- a/drivers/gpu/drm/tegra/drm.h
+++ b/drivers/gpu/drm/tegra/drm.h

@@ -39,6 +39,9 @@ struct tegra_fbdev {
 struct tegra_drm {
        struct drm_device *drm;

+       struct iommu_domain *domain;
+       struct drm_mm mm;
+
        struct mutex clients_lock;
        struct list_head clients;

diff --git a/drivers/gpu/drm/tegra/fb.c b/drivers/gpu/drm/tegra/fb.c
index 7790d43ad082..21c65dd817c3 100644
--- a/drivers/gpu/drm/tegra/fb.c
+++ b/drivers/gpu/drm/tegra/fb.c

@@ -65,8 +65,12 @@ static void tegra_fb_destroy(struct drm_framebuffer *framebuffer)
        for (i = 0; i < fb->num_planes; i++) {
                struct tegra_bo *bo = fb->planes[i];

-               if (bo)
+               if (bo) {
+                       if (bo->pages && bo->virt)
+                               vunmap(bo->virt);
+
                        drm_gem_object_unreference_unlocked(&bo->gem);
+               }
        }

        drm_framebuffer_cleanup(framebuffer);

@@ -252,6 +256,16 @@ static int tegra_fbdev_probe(struct drm_fb_helper *helper,
        offset = info->var.xoffset * bytes_per_pixel +
                 info->var.yoffset * fb->pitches[0];

+       if (bo->pages) {
+               bo->vaddr = vmap(bo->pages, bo->num_pages, VM_MAP,
+                                pgprot_writecombine(PAGE_KERNEL));
+               if (!bo->vaddr) {
+                       dev_err(drm->dev, "failed to vmap() framebuffer\n");
+                       err = -ENOMEM;
+                       goto destroy;
+               }
+       }
+
        drm->mode_config.fb_base = (resource_size_t)bo->paddr;
        info->screen_base = (void __iomem *)bo->vaddr + offset;
        info->screen_size = size;

diff --git a/drivers/gpu/drm/tegra/gem.c b/drivers/gpu/drm/tegra/gem.c
index c1e4e8b6e5ca..2912e61a2599 100644
--- a/drivers/gpu/drm/tegra/gem.c
+++ b/drivers/gpu/drm/tegra/gem.c

@@ -14,8 +14,10 @@
  */

 #include <linux/dma-buf.h>
+#include <linux/iommu.h>
 #include <drm/tegra_drm.h>

+#include "drm.h"
 #include "gem.h"

 static inline struct tegra_bo *host1x_to_tegra_bo(struct host1x_bo *bo)

@@ -90,14 +92,144 @@ static const struct host1x_bo_ops tegra_bo_ops = {
        .kunmap = tegra_bo_kunmap,
 };