The Exynos DRM driver doesn't follow the correct API when dealing with
dma_{alloc, mmap, free}_attrs functions and the
DMA_ATTR_NO_KERNEL_MAPPING attribute.
When a IOMMU is not available and the DMA_ATTR_NO_KERNEL_MAPPING is
used, the driver should use the pointer returned by dma_alloc_attr() as
a cookie.
The Exynos DRM driver directly uses the non-requested virtual
kernel address returned by the DMA mapping subsystem. This just works
now because the non-IOMMU codepath doesn't obey
DMA_ATTR_NO_KERNEL_MAPPING but we need to fix it before fixing the DMA
layer.
Signed-off-by: Carlo Caione <carlo@xxxxxxxxxx>
---
drivers/gpu/drm/exynos/exynos_drm_buf.c | 6 +++---
drivers/gpu/drm/exynos/exynos_drm_fbdev.c | 29 +++++++++--------------------
drivers/gpu/drm/exynos/exynos_drm_gem.h | 2 ++
3 files changed, 14 insertions(+), 23 deletions(-)
diff --git a/drivers/gpu/drm/exynos/exynos_drm_buf.c b/drivers/gpu/drm/exynos/exynos_drm_buf.c
index 9c80884..24994ba 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_buf.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_buf.c
@@ -63,11 +63,11 @@ static int lowlevel_buffer_allocate(struct drm_device *dev,
return -ENOMEM;
}
- buf->kvaddr = (void __iomem *)dma_alloc_attrs(dev->dev,
+ buf->cookie = dma_alloc_attrs(dev->dev,
buf->size,
&buf->dma_addr, GFP_KERNEL,
&buf->dma_attrs);
- if (!buf->kvaddr) {
+ if (!buf->cookie) {
DRM_ERROR("failed to allocate buffer.\n");
ret = -ENOMEM;
goto err_free;
@@ -132,7 +132,7 @@ static void lowlevel_buffer_deallocate(struct drm_device *dev,
buf->sgt = NULL;
if (!is_drm_iommu_supported(dev)) {
- dma_free_attrs(dev->dev, buf->size, buf->kvaddr,
+ dma_free_attrs(dev->dev, buf->size, buf->cookie,
(dma_addr_t)buf->dma_addr, &buf->dma_attrs);
drm_free_large(buf->pages);
} else
diff --git a/drivers/gpu/drm/exynos/exynos_drm_fbdev.c b/drivers/gpu/drm/exynos/exynos_drm_fbdev.c
index e12ea90..84f8dfe 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_fbdev.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_fbdev.c
@@ -79,9 +79,9 @@ static int exynos_drm_fbdev_update(struct drm_fb_helper *helper,
struct drm_framebuffer *fb)
{
struct fb_info *fbi = helper->fbdev;
- struct drm_device *dev = helper->dev;
struct exynos_drm_gem_buf *buffer;
unsigned int size = fb->width * fb->height * (fb->bits_per_pixel >> 3);
+ unsigned int nr_pages;
unsigned long offset;
drm_fb_helper_fill_fix(fbi, fb->pitches[0], fb->depth);
@@ -94,25 +94,14 @@ static int exynos_drm_fbdev_update(struct drm_fb_helper *helper,
return -EFAULT;
}
- /* map pages with kernel virtual space. */
+ nr_pages = buffer->size >> PAGE_SHIFT;
+
+ buffer->kvaddr = (void __iomem *) vmap(buffer->pages,
+ nr_pages, VM_MAP,
+ pgprot_writecombine(PAGE_KERNEL));
if (!buffer->kvaddr) {
- if (is_drm_iommu_supported(dev)) {
- unsigned int nr_pages = buffer->size >> PAGE_SHIFT;
-
- buffer->kvaddr = (void __iomem *) vmap(buffer->pages,
- nr_pages, VM_MAP,
- pgprot_writecombine(PAGE_KERNEL));
- } else {
- phys_addr_t dma_addr = buffer->dma_addr;
- if (dma_addr)
- buffer->kvaddr = (void __iomem *)phys_to_virt(dma_addr);
- else
- buffer->kvaddr = (void __iomem *)NULL;
- }
- if (!buffer->kvaddr) {
- DRM_ERROR("failed to map pages to kernel space.\n");
- return -EIO;
- }
+ DRM_ERROR("failed to map pages to kernel space.\n");
+ return -EIO;
}
/* buffer count to framebuffer always is 1 at booting time. */
@@ -313,7 +302,7 @@ static void exynos_drm_fbdev_destroy(struct drm_device *dev,
struct exynos_drm_gem_obj *exynos_gem_obj = exynos_fbd->exynos_gem_obj;
struct drm_framebuffer *fb;
- if (is_drm_iommu_supported(dev) && exynos_gem_obj->buffer->kvaddr)
+ if (exynos_gem_obj->buffer->kvaddr)
vunmap(exynos_gem_obj->buffer->kvaddr);
/* release drm framebuffer and real buffer */
diff --git a/drivers/gpu/drm/exynos/exynos_drm_gem.h b/drivers/gpu/drm/exynos/exynos_drm_gem.h
index ec58fe9..308173c 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_gem.h
+++ b/drivers/gpu/drm/exynos/exynos_drm_gem.h
@@ -22,6 +22,7 @@
/*
* exynos drm gem buffer structure.
*
+ * @cookie: cookie returned by dma_alloc_attrs
* @kvaddr: kernel virtual address to allocated memory region.
* *userptr: user space address.
* @dma_addr: bus address(accessed by dma) to allocated memory region.
@@ -35,6 +36,7 @@
* VM_PFNMAP or not.
*/
struct exynos_drm_gem_buf {
+ void *cookie;
void __iomem *kvaddr;
unsigned long userptr;
dma_addr_t dma_addr;
--
2.2.2
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