This allows access to pages allocated through the driver with optional
IOMMU mapping.
v2: Fix number of bytes copied and add write method
Original-by: Christian König <christian.koe...@amd.com>
Signed-off-by: Tom St Denis <tom.stde...@amd.com>
---
drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c | 110
++++++++++++++++++++++++++------
1 file changed, 89 insertions(+), 21 deletions(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
index b372d8d650a5..d6c56b001a2c 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
@@ -1929,38 +1929,106 @@ static const struct file_operations
amdgpu_ttm_gtt_fops = {
#endif
-static ssize_t amdgpu_iova_to_phys_read(struct file *f, char
__user *buf,
- size_t size, loff_t *pos)
+static ssize_t amdgpu_iomem_read(struct file *f, char __user *buf,
+ size_t size, loff_t *pos)
{
struct amdgpu_device *adev = file_inode(f)->i_private;
- int r;
- uint64_t phys;
struct iommu_domain *dom;
+ ssize_t result = 0;
+ int r;
- // always return 8 bytes
- if (size != 8)
- return -EINVAL;
+ dom = iommu_get_domain_for_dev(adev->dev);
- // only accept page addresses
- if (*pos & 0xFFF)
- return -EINVAL;
+ while (size) {
+ phys_addr_t addr = *pos & PAGE_MASK;
+ loff_t off = *pos & ~PAGE_MASK;
+ size_t bytes = PAGE_SIZE - off;
+ unsigned long pfn;
+ struct page *p;
+ void *ptr;
+
+ bytes = bytes < size ? bytes : size;
+
+ addr = dom ? iommu_iova_to_phys(dom, addr) : addr;
+
+ pfn = addr >> PAGE_SHIFT;
+ if (!pfn_valid(pfn))
+ return -EPERM;
+
+ p = pfn_to_page(pfn);
+ if (p->mapping != adev->mman.bdev.dev_mapping)
+ return -EPERM;
+
+ ptr = kmap(p);
+ if (ptr) {
+ r = copy_to_user(buf, ptr, bytes);
+ kunmap(p);
+ if (r)
+ return -EFAULT;
+ } else {
+ return -EFAULT;
+ }
+
+ size -= bytes;
+ *pos += bytes;
+ result += bytes;
+ }
+
+ return result;
+}
+
+static ssize_t amdgpu_iomem_write(struct file *f, const char __user
*buf,
+ size_t size, loff_t *pos)
+{
+ struct amdgpu_device *adev = file_inode(f)->i_private;
+ struct iommu_domain *dom;
+ ssize_t result = 0;
+ int r;
dom = iommu_get_domain_for_dev(adev->dev);
- if (dom)
- phys = iommu_iova_to_phys(dom, *pos);
- else
- phys = *pos;
- r = copy_to_user(buf, &phys, 8);
- if (r)
- return -EFAULT;
+ while (size) {
+ phys_addr_t addr = *pos & PAGE_MASK;
+ loff_t off = *pos & ~PAGE_MASK;
+ size_t bytes = PAGE_SIZE - off;
+ unsigned long pfn;
+ struct page *p;
+ void *ptr;
+
+ bytes = bytes < size ? bytes : size;
+
+ addr = dom ? iommu_iova_to_phys(dom, addr) : addr;
- return 8;
+ pfn = addr >> PAGE_SHIFT;
+ if (!pfn_valid(pfn))
+ return -EPERM;
+
+ p = pfn_to_page(pfn);
+ if (p->mapping != adev->mman.bdev.dev_mapping)
+ return -EPERM;
+
+ ptr = kmap(p);
+ if (ptr) {
+ r = copy_from_user(ptr, buf, bytes);
+ kunmap(p);
+ if (r)
+ return -EFAULT;
+ } else {
+ return -EFAULT;
+ }
+
+ size -= bytes;
+ *pos += bytes;
+ result += bytes;
+ }
+
+ return result;
}
-static const struct file_operations amdgpu_ttm_iova_fops = {
+static const struct file_operations amdgpu_ttm_iomem_fops = {
.owner = THIS_MODULE,
- .read = amdgpu_iova_to_phys_read,
+ .read = amdgpu_iomem_read,
+ .write = amdgpu_iomem_write,
.llseek = default_llseek
};
@@ -1973,7 +2041,7 @@ static const struct {
#ifdef CONFIG_DRM_AMDGPU_GART_DEBUGFS
{ "amdgpu_gtt", &amdgpu_ttm_gtt_fops, TTM_PL_TT },
#endif
- { "amdgpu_iova", &amdgpu_ttm_iova_fops, TTM_PL_SYSTEM },
+ { "amdgpu_iomem", &amdgpu_ttm_iomem_fops, TTM_PL_SYSTEM },
};
#endif
