[PATCH] drm/amd/amdgpu: Assign GART pages to AMD device mapping

[Tom St Denis]

This allows kernel mapped pages like the PDB and PTB to be
read via the iomem debugfs when there is no vram in the system.

Signed-off-by: Tom St Denis <tom.stde...@amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_gart.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gart.c 
b/drivers/gpu/drm/amd/amdgpu/amdgpu_gart.c
index 73b8cca35bab..f0bdbcc7b1ea 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gart.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gart.c
@@ -121,6 +121,7 @@ int amdgpu_gart_table_ram_alloc(struct amdgpu_device *adev)
        struct amdgpu_bo_param bp;
        dma_addr_t dma_addr;
        struct page *p;
+       unsigned long x;
        int ret;
 
        if (adev->gart.bo != NULL)
@@ -130,6 +131,11 @@ int amdgpu_gart_table_ram_alloc(struct amdgpu_device *adev)
        if (!p)
                return -ENOMEM;
 
+       /* assign pages to this device */
+       for (x = 0; x < (1UL << order); x++) {
+               p[x].mapping = adev->mman.bdev.dev_mapping;
+       }
+
        /* If the hardware does not support UTCL2 snooping of the CPU caches
         * then set_memory_wc() could be used as a workaround to mark the pages
         * as write combine memory.
@@ -223,6 +229,7 @@ void amdgpu_gart_table_ram_free(struct amdgpu_device *adev)
        unsigned int order = get_order(adev->gart.table_size);
        struct sg_table *sg = adev->gart.bo->tbo.sg;
        struct page *p;
+       unsigned long x;
        int ret;
 
        ret = amdgpu_bo_reserve(adev->gart.bo, false);
@@ -234,6 +241,9 @@ void amdgpu_gart_table_ram_free(struct amdgpu_device *adev)
        sg_free_table(sg);
        kfree(sg);
        p = virt_to_page(adev->gart.ptr);
+       for (x = 0; x < (1UL << order); x++) {
+               p[x].mapping = NULL;
+       }
        __free_pages(p, order);
 
        adev->gart.ptr = NULL;
-- 
2.40.1