drm/exynos: consider buffer allocation without iommu

This patch fixes the issue that when buffer allocation is requested
without iommu, the allocation is failed.

Without iommu, dma_alloc_attrs function allocates some memory region
and returns cpu address so this patch makes the cpu address to be set
to buf->kvaddr correctly.

Changelog v2:
- fix buffer free
  . Without iommu, dma_free_attrs function requires kernel space address
    as argument. So it changes the argument, buf->pages to buf->kvaddr.

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

1 files changed, 48 insertions, 7 deletions

diff --git a/drivers/gpu/drm/exynos/exynos_drm_buf.c b/drivers/gpu/drm/exynos/exynos_drm_buf.c
index 13a8489b39ff..b7937a616e46 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_buf.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_buf.c
@@ -15,6 +15,7 @@
 #include "exynos_drm_drv.h"
 #include "exynos_drm_gem.h"
 #include "exynos_drm_buf.h"
+#include "exynos_drm_iommu.h"
 
 static int lowlevel_buffer_allocate(struct drm_device *dev,
                 unsigned int flags, struct exynos_drm_gem_buf *buf)
@@ -52,14 +53,45 @@ static int lowlevel_buffer_allocate(struct drm_device *dev,
         dma_set_attr(attr, &buf->dma_attrs);
         dma_set_attr(DMA_ATTR_NO_KERNEL_MAPPING, &buf->dma_attrs);
 
-        buf->pages = dma_alloc_attrs(dev->dev, buf->size,
-                        &buf->dma_addr, GFP_KERNEL, &buf->dma_attrs);
-        if (!buf->pages) {
-                DRM_ERROR("failed to allocate buffer.\n");
-                return -ENOMEM;
+        nr_pages = buf->size >> PAGE_SHIFT;
+
+        if (!is_drm_iommu_supported(dev)) {
+                dma_addr_t start_addr;
+                unsigned int i = 0;
+
+                buf->pages = kzalloc(sizeof(struct page) * nr_pages,
+                                        GFP_KERNEL);
+                if (!buf->pages) {
+                        DRM_ERROR("failed to allocate pages.\n");
+                        return -ENOMEM;
+                }
+
+                buf->kvaddr = dma_alloc_attrs(dev->dev, buf->size,
+                                        &buf->dma_addr, GFP_KERNEL,
+                                        &buf->dma_attrs);
+                if (!buf->kvaddr) {
+                        DRM_ERROR("failed to allocate buffer.\n");
+                        kfree(buf->pages);
+                        return -ENOMEM;
+                }
+
+                start_addr = buf->dma_addr;
+                while (i < nr_pages) {
+                        buf->pages[i] = phys_to_page(start_addr);
+                        start_addr += PAGE_SIZE;
+                        i++;
+                }
+        } else {
+
+                buf->pages = dma_alloc_attrs(dev->dev, buf->size,
+                                        &buf->dma_addr, GFP_KERNEL,
+                                        &buf->dma_attrs);
+                if (!buf->pages) {
+                        DRM_ERROR("failed to allocate buffer.\n");
+                        return -ENOMEM;
+                }
         }
 
-        nr_pages = buf->size >> PAGE_SHIFT;
         buf->sgt = drm_prime_pages_to_sg(buf->pages, nr_pages);
         if (!buf->sgt) {
                 DRM_ERROR("failed to get sg table.\n");
@@ -78,6 +110,9 @@ err_free_attrs:
                         (dma_addr_t)buf->dma_addr, &buf->dma_attrs);
         buf->dma_addr = (dma_addr_t)NULL;
 
+        if (!is_drm_iommu_supported(dev))
+                kfree(buf->pages);
+
         return ret;
 }
 
@@ -100,8 +135,14 @@ static void lowlevel_buffer_deallocate(struct drm_device *dev,
         kfree(buf->sgt);
         buf->sgt = NULL;
 
-        dma_free_attrs(dev->dev, buf->size, buf->pages,
+        if (!is_drm_iommu_supported(dev)) {
+                dma_free_attrs(dev->dev, buf->size, buf->kvaddr,
                                 (dma_addr_t)buf->dma_addr, &buf->dma_attrs);
+                kfree(buf->pages);
+        } else
+                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;
 }