[PATCH 2/4] drm/amd/amdgpu: add support for iova_to_phys to replace TTM trace

[Tom St Denis]

Signed-off-by: Tom St Denis <tom.stdenis at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c | 32 ++++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
index 7848ffa99eb4..b4c298925e2a 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
@@ -43,6 +43,7 @@
 #include <linux/swap.h>
 #include <linux/pagemap.h>
 #include <linux/debugfs.h>
+#include <linux/iommu.h>
 #include "amdgpu.h"
 #include "amdgpu_trace.h"
 #include "bif/bif_4_1_d.h"
@@ -1810,6 +1811,36 @@ 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)
+{
+	struct amdgpu_device *adev = file_inode(f)->i_private;
+	int r;
+	uint64_t phys;
+
+	// always return 8 bytes 
+	if (size != 8)
+		return -EINVAL;
+
+	// only accept page addresses
+	if (*pos & 0xFFF)
+		return -EINVAL;
+
+
+	phys = iommu_iova_to_phys(iommu_get_domain_for_dev(adev->dev), *pos);
+
+	r = copy_to_user(buf, &phys, 8);
+	if (r)
+		return -EFAULT;
+
+	return 8;
+}
+
+static const struct file_operations amdgpu_ttm_iova_fops = {
+	.owner = THIS_MODULE,
+	.read = amdgpu_iova_to_phys_read,
+	.llseek = default_llseek
+};
 
 static const struct {
 	char *name;
@@ -1819,6 +1850,7 @@ static const struct {
 #ifdef CONFIG_DRM_AMDGPU_GART_DEBUGFS
 	{ "amdgpu_gtt", &amdgpu_ttm_gtt_fops },
 #endif
+	{ "amdgpu_iova", &amdgpu_ttm_iova_fops },
 };
 
 #endif
-- 
2.12.0