drm/tegra: Add IOMMU support
authorThierry Reding <treding@nvidia.com>
Thu, 26 Jun 2014 19:41:53 +0000 (21:41 +0200)
committerThierry Reding <treding@nvidia.com>
Thu, 13 Nov 2014 15:14:48 +0000 (16:14 +0100)
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 <treding@nvidia.com>
drivers/gpu/drm/tegra/dc.c
drivers/gpu/drm/tegra/drm.c
drivers/gpu/drm/tegra/drm.h
drivers/gpu/drm/tegra/fb.c
drivers/gpu/drm/tegra/gem.c
drivers/gpu/drm/tegra/gem.h

index 4a01523..5f138b7 100644 (file)
@@ -9,6 +9,7 @@
 
 #include <linux/clk.h>
 #include <linux/debugfs.h>
+#include <linux/iommu.h>
 #include <linux/reset.h>
 
 #include <soc/tegra/pmc.h>
@@ -1290,6 +1291,17 @@ static int tegra_dc_init(struct host1x_client *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 domain: %d\n",
+                               err);
+                       return err;
+               }
+
+               dc->domain = tegra->domain;
+       }
+
        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);
@@ -1347,6 +1359,11 @@ static int tegra_dc_exit(struct host1x_client *client)
                return err;
        }
 
+       if (dc->domain) {
+               iommu_detach_device(dc->domain, dc->dev);
+               dc->domain = NULL;
+       }
+
        return 0;
 }
 
index e1632fb..6c9df79 100644 (file)
@@ -8,6 +8,7 @@
  */
 
 #include <linux/host1x.h>
+#include <linux/iommu.h>
 
 #include "drm.h"
 #include "gem.h"
@@ -33,6 +34,17 @@ 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)) {
+                       err = PTR_ERR(tegra->domain);
+                       goto free;
+               }
+
+               DRM_DEBUG("IOMMU context initialized\n");
+               drm_mm_init(&tegra->mm, 0, SZ_2G);
+       }
+
        mutex_init(&tegra->clients_lock);
        INIT_LIST_HEAD(&tegra->clients);
        drm->dev_private = tegra;
@@ -76,6 +88,12 @@ fbdev:
        tegra_drm_fb_free(drm);
 config:
        drm_mode_config_cleanup(drm);
+
+       if (tegra->domain) {
+               iommu_domain_free(tegra->domain);
+               drm_mm_takedown(&tegra->mm);
+       }
+free:
        kfree(tegra);
        return err;
 }
@@ -83,6 +101,7 @@ config:
 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);
@@ -94,6 +113,11 @@ 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;
 }
 
index ef2faae..96ff47d 100644 (file)
@@ -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;
 
@@ -121,6 +124,8 @@ struct tegra_dc {
        struct drm_pending_vblank_event *event;
 
        const struct tegra_dc_soc_info *soc;
+
+       struct iommu_domain *domain;
 };
 
 static inline struct tegra_dc *
index 0474241..fab39eb 100644 (file)
@@ -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->vaddr)
+                               vunmap(bo->vaddr);
+
                        drm_gem_object_unreference_unlocked(&bo->gem);
+               }
        }
 
        drm_framebuffer_cleanup(framebuffer);
@@ -254,6 +258,16 @@ 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;
index 9905598..8b1095d 100644 (file)
@@ -14,6 +14,7 @@
  */
 
 #include <linux/dma-buf.h>
+#include <linux/iommu.h>
 #include <drm/tegra_drm.h>
 
 #include "drm.h"
@@ -91,6 +92,88 @@ static const struct host1x_bo_ops tegra_bo_ops = {
        .kunmap = tegra_bo_kunmap,
 };
 
+/*
+ * A generic iommu_map_sg() function is being reviewed and will hopefully be
+ * merged soon. At that point this function can be dropped in favour of the
+ * one provided by the IOMMU API.
+ */
+static ssize_t __iommu_map_sg(struct iommu_domain *domain, unsigned long iova,
+                             struct scatterlist *sg, unsigned int nents,
+                             int prot)
+{
+       struct scatterlist *s;
+       size_t offset = 0;
+       unsigned int i;
+       int err;
+
+       for_each_sg(sg, s, nents, i) {
+               phys_addr_t phys = page_to_phys(sg_page(s));
+               size_t length = s->offset + s->length;
+
+               err = iommu_map(domain, iova + offset, phys, length, prot);
+               if (err < 0) {
+                       iommu_unmap(domain, iova, offset);
+                       return err;
+               }
+
+               offset += length;
+       }
+
+       return offset;
+}
+
+static int tegra_bo_iommu_map(struct tegra_drm *tegra, struct tegra_bo *bo)
+{
+       int prot = IOMMU_READ | IOMMU_WRITE;
+       ssize_t err;
+
+       if (bo->mm)
+               return -EBUSY;
+
+       bo->mm = kzalloc(sizeof(*bo->mm), GFP_KERNEL);
+       if (!bo->mm)
+               return -ENOMEM;
+
+       err = drm_mm_insert_node_generic(&tegra->mm, bo->mm, bo->gem.size,
+                                        PAGE_SIZE, 0, 0, 0);
+       if (err < 0) {
+               dev_err(tegra->drm->dev, "out of I/O virtual memory: %zd\n",
+                       err);
+               goto free;
+       }
+
+       bo->paddr = bo->mm->start;
+
+       err = __iommu_map_sg(tegra->domain, bo->paddr, bo->sgt->sgl,
+                            bo->sgt->nents, prot);
+       if (err < 0) {
+               dev_err(tegra->drm->dev, "failed to map buffer: %zd\n", err);
+               goto remove;
+       }
+
+       bo->size = err;
+
+       return 0;
+
+remove:
+       drm_mm_remove_node(bo->mm);
+free:
+       kfree(bo->mm);
+       return err;
+}
+
+static int tegra_bo_iommu_unmap(struct tegra_drm *tegra, struct tegra_bo *bo)
+{
+       if (!bo->mm)
+               return 0;
+
+       iommu_unmap(tegra->domain, bo->paddr, bo->size);
+       drm_mm_remove_node(bo->mm);
+       kfree(bo->mm);
+
+       return 0;
+}
+
 static struct tegra_bo *tegra_bo_alloc_object(struct drm_device *drm,
                                              size_t size)
 {
@@ -121,9 +204,64 @@ free:
        return ERR_PTR(err);
 }
 
-static void tegra_bo_destroy(struct drm_device *drm, struct tegra_bo *bo)
+static void tegra_bo_free(struct drm_device *drm, struct tegra_bo *bo)
+{
+       if (bo->pages) {
+               drm_gem_put_pages(&bo->gem, bo->pages, true, true);
+               sg_free_table(bo->sgt);
+               kfree(bo->sgt);
+       } else {
+               dma_free_writecombine(drm->dev, bo->gem.size, bo->vaddr,
+                                     bo->paddr);
+       }
+}
+
+static int tegra_bo_get_pages(struct drm_device *drm, struct tegra_bo *bo,
+                             size_t size)
+{
+       bo->pages = drm_gem_get_pages(&bo->gem);
+       if (IS_ERR(bo->pages))
+               return PTR_ERR(bo->pages);
+
+       bo->num_pages = size >> PAGE_SHIFT;
+
+       bo->sgt = drm_prime_pages_to_sg(bo->pages, bo->num_pages);
+       if (IS_ERR(bo->sgt)) {
+               drm_gem_put_pages(&bo->gem, bo->pages, false, false);
+               return PTR_ERR(bo->sgt);
+       }
+
+       return 0;
+}
+
+static int tegra_bo_alloc(struct drm_device *drm, struct tegra_bo *bo,
+                         size_t size)
 {
-       dma_free_writecombine(drm->dev, bo->gem.size, bo->vaddr, bo->paddr);
+       struct tegra_drm *tegra = drm->dev_private;
+       int err;
+
+       if (tegra->domain) {
+               err = tegra_bo_get_pages(drm, bo, size);
+               if (err < 0)
+                       return err;
+
+               err = tegra_bo_iommu_map(tegra, bo);
+               if (err < 0) {
+                       tegra_bo_free(drm, bo);
+                       return err;
+               }
+       } else {
+               bo->vaddr = dma_alloc_writecombine(drm->dev, size, &bo->paddr,
+                                                  GFP_KERNEL | __GFP_NOWARN);
+               if (!bo->vaddr) {
+                       dev_err(drm->dev,
+                               "failed to allocate buffer of size %zu\n",
+                               size);
+                       return -ENOMEM;
+               }
+       }
+
+       return 0;
 }
 
 struct tegra_bo *tegra_bo_create(struct drm_device *drm, unsigned int size,
@@ -136,14 +274,9 @@ struct tegra_bo *tegra_bo_create(struct drm_device *drm, unsigned int size,
        if (IS_ERR(bo))
                return bo;
 
-       bo->vaddr = dma_alloc_writecombine(drm->dev, size, &bo->paddr,
-                                          GFP_KERNEL | __GFP_NOWARN);
-       if (!bo->vaddr) {
-               dev_err(drm->dev, "failed to allocate buffer with size %u\n",
-                       size);
-               err = -ENOMEM;
-               goto err_dma;
-       }
+       err = tegra_bo_alloc(drm, bo, size);
+       if (err < 0)
+               goto release;
 
        if (flags & DRM_TEGRA_GEM_CREATE_TILED)
                bo->tiling.mode = TEGRA_BO_TILING_MODE_TILED;
@@ -153,9 +286,9 @@ struct tegra_bo *tegra_bo_create(struct drm_device *drm, unsigned int size,
 
        return bo;
 
-err_dma:
+release:
+       drm_gem_object_release(&bo->gem);
        kfree(bo);
-
        return ERR_PTR(err);
 }
 
@@ -186,6 +319,7 @@ struct tegra_bo *tegra_bo_create_with_handle(struct drm_file *file,
 static struct tegra_bo *tegra_bo_import(struct drm_device *drm,
                                        struct dma_buf *buf)
 {
+       struct tegra_drm *tegra = drm->dev_private;
        struct dma_buf_attachment *attach;
        struct tegra_bo *bo;
        int err;
@@ -213,12 +347,19 @@ static struct tegra_bo *tegra_bo_import(struct drm_device *drm,
                goto detach;
        }
 
-       if (bo->sgt->nents > 1) {
-               err = -EINVAL;
-               goto detach;
+       if (tegra->domain) {
+               err = tegra_bo_iommu_map(tegra, bo);
+               if (err < 0)
+                       goto detach;
+       } else {
+               if (bo->sgt->nents > 1) {
+                       err = -EINVAL;
+                       goto detach;
+               }
+
+               bo->paddr = sg_dma_address(bo->sgt->sgl);
        }
 
-       bo->paddr = sg_dma_address(bo->sgt->sgl);
        bo->gem.import_attach = attach;
 
        return bo;
@@ -237,14 +378,18 @@ free:
 
 void tegra_bo_free_object(struct drm_gem_object *gem)
 {
+       struct tegra_drm *tegra = gem->dev->dev_private;
        struct tegra_bo *bo = to_tegra_bo(gem);
 
+       if (tegra->domain)
+               tegra_bo_iommu_unmap(tegra, bo);
+
        if (gem->import_attach) {
                dma_buf_unmap_attachment(gem->import_attach, bo->sgt,
                                         DMA_TO_DEVICE);
                drm_prime_gem_destroy(gem, NULL);
        } else {
-               tegra_bo_destroy(gem->dev, bo);
+               tegra_bo_free(gem->dev, bo);
        }
 
        drm_gem_object_release(gem);
@@ -299,14 +444,44 @@ int tegra_bo_dumb_map_offset(struct drm_file *file, struct drm_device *drm,
        return 0;
 }
 
+static int tegra_bo_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
+{
+       struct drm_gem_object *gem = vma->vm_private_data;
+       struct tegra_bo *bo = to_tegra_bo(gem);
+       struct page *page;
+       pgoff_t offset;
+       int err;
+
+       if (!bo->pages)
+               return VM_FAULT_SIGBUS;
+
+       offset = ((unsigned long)vmf->virtual_address - vma->vm_start) >> PAGE_SHIFT;
+       page = bo->pages[offset];
+
+       err = vm_insert_page(vma, (unsigned long)vmf->virtual_address, page);
+       switch (err) {
+       case -EAGAIN:
+       case 0:
+       case -ERESTARTSYS:
+       case -EINTR:
+       case -EBUSY:
+               return VM_FAULT_NOPAGE;
+
+       case -ENOMEM:
+               return VM_FAULT_OOM;
+       }
+
+       return VM_FAULT_SIGBUS;
+}
+
 const struct vm_operations_struct tegra_bo_vm_ops = {
+       .fault = tegra_bo_fault,
        .open = drm_gem_vm_open,
        .close = drm_gem_vm_close,
 };
 
 int tegra_drm_mmap(struct file *file, struct vm_area_struct *vma)
 {
-       unsigned long vm_pgoff = vma->vm_pgoff;
        struct drm_gem_object *gem;
        struct tegra_bo *bo;
        int ret;
@@ -318,17 +493,28 @@ int tegra_drm_mmap(struct file *file, struct vm_area_struct *vma)
        gem = vma->vm_private_data;
        bo = to_tegra_bo(gem);
 
-       vma->vm_flags &= ~VM_PFNMAP;
-       vma->vm_pgoff = 0;
+       if (!bo->pages) {
+               unsigned long vm_pgoff = vma->vm_pgoff;
 
-       ret = dma_mmap_writecombine(gem->dev->dev, vma, bo->vaddr, bo->paddr,
-                                   gem->size);
-       if (ret) {
-               drm_gem_vm_close(vma);
-               return ret;
-       }
+               vma->vm_flags &= ~VM_PFNMAP;
+               vma->vm_pgoff = 0;
 
-       vma->vm_pgoff = vm_pgoff;
+               ret = dma_mmap_writecombine(gem->dev->dev, vma, bo->vaddr,
+                                           bo->paddr, gem->size);
+               if (ret) {
+                       drm_gem_vm_close(vma);
+                       return ret;
+               }
+
+               vma->vm_pgoff = vm_pgoff;
+       } else {
+               pgprot_t prot = vm_get_page_prot(vma->vm_flags);
+
+               vma->vm_flags |= VM_MIXEDMAP;
+               vma->vm_flags &= ~VM_PFNMAP;
+
+               vma->vm_page_prot = pgprot_writecombine(prot);
+       }
 
        return 0;
 }
@@ -345,21 +531,44 @@ tegra_gem_prime_map_dma_buf(struct dma_buf_attachment *attach,
        if (!sgt)
                return NULL;
 
-       if (sg_alloc_table(sgt, 1, GFP_KERNEL)) {
-               kfree(sgt);
-               return NULL;
-       }
+       if (bo->pages) {
+               struct scatterlist *sg;
+               unsigned int i;
+
+               if (sg_alloc_table(sgt, bo->num_pages, GFP_KERNEL))
+                       goto free;
 
-       sg_dma_address(sgt->sgl) = bo->paddr;
-       sg_dma_len(sgt->sgl) = gem->size;
+               for_each_sg(sgt->sgl, sg, bo->num_pages, i)
+                       sg_set_page(sg, bo->pages[i], PAGE_SIZE, 0);
+
+               if (dma_map_sg(attach->dev, sgt->sgl, sgt->nents, dir) == 0)
+                       goto free;
+       } else {
+               if (sg_alloc_table(sgt, 1, GFP_KERNEL))
+                       goto free;
+
+               sg_dma_address(sgt->sgl) = bo->paddr;
+               sg_dma_len(sgt->sgl) = gem->size;
+       }
 
        return sgt;
+
+free:
+       sg_free_table(sgt);
+       kfree(sgt);
+       return NULL;
 }
 
 static void tegra_gem_prime_unmap_dma_buf(struct dma_buf_attachment *attach,
                                          struct sg_table *sgt,
                                          enum dma_data_direction dir)
 {
+       struct drm_gem_object *gem = attach->dmabuf->priv;
+       struct tegra_bo *bo = to_tegra_bo(gem);
+
+       if (bo->pages)
+               dma_unmap_sg(attach->dev, sgt->sgl, sgt->nents, dir);
+
        sg_free_table(sgt);
        kfree(sgt);
 }
index 6538b56..3dd4165 100644 (file)
@@ -38,6 +38,12 @@ struct tegra_bo {
        dma_addr_t paddr;
        void *vaddr;
 
+       struct drm_mm_node *mm;
+       unsigned long num_pages;
+       struct page **pages;
+       /* size of IOMMU mapping */
+       size_t size;
+
        struct tegra_bo_tiling tiling;
 };