drm/exynos: use DMA_ATTR_NO_KERNEL_MAPPING attribute

Changelog v3:
just code cleanup.

Changelog v2:
fix argument to dma_mmap_attr function.
- use pages instead of kvaddr because kvaddr is 0 with
  DMA_ATTR_NO_KERNEL_MAPPING.

Changelog v1:
When gem allocation is requested, kernel space mapping isn't needed.
But if need, such as console framebuffer, the physical pages would be
mapped with kernel space though vmap function.

Signed-off-by: Inki Dae <inki.dae@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>

5 files changed, 32 insertions, 25 deletions

diff --git a/drivers/gpu/drm/exynos/exynos_drm_buf.c b/drivers/gpu/drm/exynos/exynos_drm_buf.c
index 72bf97b96ba..9732043d91e 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_buf.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_buf.c
@@ -35,6 +35,7 @@ static int lowlevel_buffer_allocate(struct drm_device *dev,
 {
         int ret = 0;
         enum dma_attr attr = DMA_ATTR_FORCE_CONTIGUOUS;
+        unsigned int nr_pages;
 
         DRM_DEBUG_KMS("%s\n", __FILE__);
 
@@ -49,40 +50,31 @@ static int lowlevel_buffer_allocate(struct drm_device *dev,
                 attr = DMA_ATTR_WRITE_COMBINE;
 
         dma_set_attr(attr, &buf->dma_attrs);
+        dma_set_attr(DMA_ATTR_NO_KERNEL_MAPPING, &buf->dma_attrs);
 
-        buf->kvaddr = dma_alloc_attrs(dev->dev, buf->size,
+        buf->pages = dma_alloc_attrs(dev->dev, buf->size,
                         &buf->dma_addr, GFP_KERNEL, &buf->dma_attrs);
-        if (!buf->kvaddr) {
+        if (!buf->pages) {
                 DRM_ERROR("failed to allocate buffer.\n");
                 return -ENOMEM;
         }
 
-        buf->sgt = kzalloc(sizeof(struct sg_table), GFP_KERNEL);
+        nr_pages = buf->size >> PAGE_SHIFT;
+        buf->sgt = drm_prime_pages_to_sg(buf->pages, nr_pages);
         if (!buf->sgt) {
-                DRM_ERROR("failed to allocate sg table.\n");
+                DRM_ERROR("failed to get sg table.\n");
                 ret = -ENOMEM;
                 goto err_free_attrs;
         }
 
-        ret = dma_get_sgtable(dev->dev, buf->sgt, buf->kvaddr, buf->dma_addr,
-                        buf->size);
-        if (ret < 0) {
-                DRM_ERROR("failed to get sgtable.\n");
-                goto err_free_sgt;
-        }
-
-        DRM_DEBUG_KMS("vaddr(0x%lx), dma_addr(0x%lx), size(0x%lx)\n",
-                        (unsigned long)buf->kvaddr,
+        DRM_DEBUG_KMS("dma_addr(0x%lx), size(0x%lx)\n",
                         (unsigned long)buf->dma_addr,
                         buf->size);
 
         return ret;
 
-err_free_sgt:
-        kfree(buf->sgt);
-        buf->sgt = NULL;
 err_free_attrs:
-        dma_free_attrs(dev->dev, buf->size, buf->kvaddr,
+        dma_free_attrs(dev->dev, buf->size, buf->pages,
                         (dma_addr_t)buf->dma_addr, &buf->dma_attrs);
         buf->dma_addr = (dma_addr_t)NULL;
 
@@ -99,8 +91,7 @@ static void lowlevel_buffer_deallocate(struct drm_device *dev,
                 return;
         }
 
-        DRM_DEBUG_KMS("vaddr(0x%lx), dma_addr(0x%lx), size(0x%lx)\n",
-                        (unsigned long)buf->kvaddr,
+        DRM_DEBUG_KMS("dma_addr(0x%lx), size(0x%lx)\n",
                         (unsigned long)buf->dma_addr,
                         buf->size);
 
@@ -109,7 +100,7 @@ static void lowlevel_buffer_deallocate(struct drm_device *dev,
         kfree(buf->sgt);
         buf->sgt = NULL;
 
-        dma_free_attrs(dev->dev, buf->size, buf->kvaddr,
+        dma_free_attrs(dev->dev, buf->size, buf->pages,
                                 (dma_addr_t)buf->dma_addr, &buf->dma_attrs);
         buf->dma_addr = (dma_addr_t)NULL;
 }
diff --git a/drivers/gpu/drm/exynos/exynos_drm_fb.c b/drivers/gpu/drm/exynos/exynos_drm_fb.c
index 7413f4b729b..764571c9625 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_fb.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_fb.c
@@ -297,9 +297,7 @@ struct exynos_drm_gem_buf *exynos_drm_fb_buffer(struct drm_framebuffer *fb,
         if (!buffer)
                 return NULL;
 
-        DRM_DEBUG_KMS("vaddr = 0x%lx, dma_addr = 0x%lx\n",
-                        (unsigned long)buffer->kvaddr,
-                        (unsigned long)buffer->dma_addr);
+        DRM_DEBUG_KMS("dma_addr = 0x%lx\n", (unsigned long)buffer->dma_addr);
 
         return buffer;
 }
diff --git a/drivers/gpu/drm/exynos/exynos_drm_fbdev.c b/drivers/gpu/drm/exynos/exynos_drm_fbdev.c
index 885ef235d59..f433eb7533a 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_fbdev.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_fbdev.c
@@ -65,7 +65,7 @@ static int exynos_drm_fb_mmap(struct fb_info *info,
         if (vm_size > buffer->size)
                 return -EINVAL;
 
-        ret = dma_mmap_attrs(helper->dev->dev, vma, buffer->kvaddr,
+        ret = dma_mmap_attrs(helper->dev->dev, vma, buffer->pages,
                 buffer->dma_addr, buffer->size, &buffer->dma_attrs);
         if (ret < 0) {
                 DRM_ERROR("failed to mmap.\n");
@@ -109,6 +109,17 @@ static int exynos_drm_fbdev_update(struct drm_fb_helper *helper,
                 return -EFAULT;
         }
 
+        /* map pages with kernel virtual space. */
+        if (!buffer->kvaddr) {
+                unsigned int nr_pages = buffer->size >> PAGE_SHIFT;
+                buffer->kvaddr = vmap(buffer->pages, nr_pages, VM_MAP,
+                                        pgprot_writecombine(PAGE_KERNEL));
+                if (!buffer->kvaddr) {
+                        DRM_ERROR("failed to map pages to kernel space.\n");
+                        return -EIO;
+                }
+        }
+
         /* buffer count to framebuffer always is 1 at booting time. */
         exynos_drm_fb_set_buf_cnt(fb, 1);
 
@@ -305,8 +316,13 @@ err_init:
 static void exynos_drm_fbdev_destroy(struct drm_device *dev,
                                       struct drm_fb_helper *fb_helper)
 {
+        struct exynos_drm_fbdev *exynos_fbd = to_exynos_fbdev(fb_helper);
+        struct exynos_drm_gem_obj *exynos_gem_obj = exynos_fbd->exynos_gem_obj;
         struct drm_framebuffer *fb;
 
+        if (exynos_gem_obj->buffer->kvaddr)
+                vunmap(exynos_gem_obj->buffer->kvaddr);
+
         /* release drm framebuffer and real buffer */
         if (fb_helper->fb && fb_helper->fb->funcs) {
                 fb = fb_helper->fb;
diff --git a/drivers/gpu/drm/exynos/exynos_drm_gem.c b/drivers/gpu/drm/exynos/exynos_drm_gem.c
index 99227246ce8..d48183e7e05 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_gem.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_gem.c
@@ -400,7 +400,7 @@ static int exynos_drm_gem_mmap_buffer(struct file *filp,
         if (vm_size > buffer->size)
                 return -EINVAL;
 
-        ret = dma_mmap_attrs(drm_dev->dev, vma, buffer->kvaddr,
+        ret = dma_mmap_attrs(drm_dev->dev, vma, buffer->pages,
                                 buffer->dma_addr, buffer->size,
                                 &buffer->dma_attrs);
         if (ret < 0) {
diff --git a/drivers/gpu/drm/exynos/exynos_drm_gem.h b/drivers/gpu/drm/exynos/exynos_drm_gem.h
index d3ea106a9a7..f11f2afd5bf 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_gem.h
+++ b/drivers/gpu/drm/exynos/exynos_drm_gem.h
@@ -40,6 +40,7 @@
  *      - this address could be physical address without IOMMU and
  *      device address with IOMMU.
  * @write: whether pages will be written to by the caller.
+ * @pages: Array of backing pages.
  * @sgt: sg table to transfer page data.
  * @size: size of allocated memory region.
  * @pfnmap: indicate whether memory region from userptr is mmaped with
@@ -51,6 +52,7 @@ struct exynos_drm_gem_buf {
         dma_addr_t              dma_addr;
         struct dma_attrs        dma_attrs;
         unsigned int            write;
+        struct page             **pages;
         struct sg_table         *sgt;
         unsigned long           size;
         bool                    pfnmap;