target/linux/brcm2708/patches-4.9/950-0182-drm-vc4-Verify-at-boot-that-CMA-doesn-t-cross-a-256M.patch

   1 From b280acf3c32746106c81419390f5b1869d644f66 Mon Sep 17 00:00:00 2001
   2 From: Eric Anholt <eric@anholt.net>
   3 Date: Mon, 12 Oct 2015 08:58:08 -0700
   4 Subject: [PATCH] drm/vc4: Verify at boot that CMA doesn't cross a 256MB
   5  boundary.
   6
   7 I've seen lots of users cranking CMA up higher, so throw an error if
   8 they do.
   9
  10 Signed-off-by: Eric Anholt <eric@anholt.net>
  11 ---
  12  drivers/base/dma-contiguous.c |  1 +
  13  drivers/gpu/drm/vc4/vc4_v3d.c | 18 ++++++++++++++++++
  14  mm/cma.c                      |  2 ++
  15  3 files changed, 21 insertions(+)
  16
  17 --- a/drivers/base/dma-contiguous.c
  18 +++ b/drivers/base/dma-contiguous.c
  19 @@ -35,6 +35,7 @@
  20  #endif
  21
  22  struct cma *dma_contiguous_default_area;
  23 +EXPORT_SYMBOL(dma_contiguous_default_area);
  24
  25  /*
  26   * Default global CMA area size can be defined in kernel's .config.
  27 --- a/drivers/gpu/drm/vc4/vc4_v3d.c
  28 +++ b/drivers/gpu/drm/vc4/vc4_v3d.c
  29 @@ -16,7 +16,10 @@
  30   * this program.  If not, see <http://www.gnu.org/licenses/>.
  31   */
  32
  33 +#include "linux/init.h"
  34 +#include "linux/cma.h"
  35  #include "linux/component.h"
  36 +#include "linux/dma-contiguous.h"
  37  #include "linux/pm_runtime.h"
  38  #include "vc4_drv.h"
  39  #include "vc4_regs.h"
  40 @@ -188,8 +191,23 @@ static int vc4_v3d_bind(struct device *d
  41         struct drm_device *drm = dev_get_drvdata(master);
  42         struct vc4_dev *vc4 = to_vc4_dev(drm);
  43         struct vc4_v3d *v3d = NULL;
  44 +       struct cma *cma;
  45         int ret;
  46
  47 +       cma = dev_get_cma_area(dev);
  48 +       if (!cma)
  49 +               return -EINVAL;
  50 +
  51 +       if ((cma_get_base(cma) & 0xf0000000) !=
  52 +           ((cma_get_base(cma) + cma_get_size(cma) - 1) & 0xf0000000)) {
  53 +               DRM_ERROR("V3D requires that the CMA area (0x%08lx - 0x%08lx) "
  54 +                         "not span a 256MB boundary, or memory corruption "
  55 +                         "would happen.\n",
  56 +                         (long)cma_get_base(cma),
  57 +                         cma_get_base(cma) + cma_get_size(cma));
  58 +               return -EINVAL;
  59 +       }
  60 +
  61         v3d = devm_kzalloc(&pdev->dev, sizeof(*v3d), GFP_KERNEL);
  62         if (!v3d)
  63                 return -ENOMEM;
  64 --- a/mm/cma.c
  65 +++ b/mm/cma.c
  66 @@ -47,11 +47,13 @@ phys_addr_t cma_get_base(const struct cm
  67  {
  68         return PFN_PHYS(cma->base_pfn);
  69  }
  70 +EXPORT_SYMBOL(cma_get_base);
  71
  72  unsigned long cma_get_size(const struct cma *cma)
  73  {
  74         return cma->count << PAGE_SHIFT;
  75  }
  76 +EXPORT_SYMBOL(cma_get_size);
  77
  78  static unsigned long cma_bitmap_aligned_mask(const struct cma *cma,
  79                                              unsigned int align_order)