From: Chunming Zhou <david1.zhou@amd.com>
Date: Fri, 9 Feb 2018 10:44:10 +0800
Subject: drm/radeon: only enable swiotlb path when need v2
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Git-commit: 1bc3d3cce8c3b44c2b5ac6cee98c830bb40e6b0f
Patch-mainline: v4.17-rc1
References: FATE#326289 FATE#326079 FATE#326049 FATE#322398 FATE#326166

swiotlb expands our card accessing range, but its path always is slower
than ttm pool allocation.
So add condition to use it.
v2: move a bit later

Signed-off-by: Chunming Zhou <david1.zhou@amd.com>
Reviewed-by: Monk Liu <monk.liu@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180209024410.1469-3-david1.zhou@amd.com

Acked-by: Petr Tesarik <ptesarik@suse.com>
---
 drivers/gpu/drm/radeon/radeon.h        |    1 +
 drivers/gpu/drm/radeon/radeon_device.c |    2 ++
 drivers/gpu/drm/radeon/radeon_ttm.c    |    6 +++---
 3 files changed, 6 insertions(+), 3 deletions(-)

--- a/drivers/gpu/drm/radeon/radeon.h
+++ b/drivers/gpu/drm/radeon/radeon.h
@@ -2387,6 +2387,7 @@ struct radeon_device {
 	struct radeon_dummy_page	dummy_page;
 	bool				shutdown;
 	bool				need_dma32;
+	bool				need_swiotlb;
 	bool				accel_working;
 	bool				fastfb_working; /* IGP feature*/
 	bool				needs_reset, in_reset;
--- a/drivers/gpu/drm/radeon/radeon_device.c
+++ b/drivers/gpu/drm/radeon/radeon_device.c
@@ -29,6 +29,7 @@
 #include <linux/slab.h>
 #include <drm/drmP.h>
 #include <drm/drm_crtc_helper.h>
+#include <drm/drm_cache.h>
 #include <drm/radeon_drm.h>
 #include <linux/pm_runtime.h>
 #include <linux/vgaarb.h>
@@ -1382,6 +1383,7 @@ int radeon_device_init(struct radeon_dev
 		pci_set_consistent_dma_mask(rdev->pdev, DMA_BIT_MASK(32));
 		pr_warn("radeon: No coherent DMA available\n");
 	}
+	rdev->need_swiotlb = drm_get_max_iomem() > ((u64)1 << dma_bits);
 
 	/* Registers mapping */
 	/* TODO: block userspace mapping of io register */
--- a/drivers/gpu/drm/radeon/radeon_ttm.c
+++ b/drivers/gpu/drm/radeon/radeon_ttm.c
@@ -756,7 +756,7 @@ static int radeon_ttm_tt_populate(struct
 #endif
 
 #ifdef CONFIG_SWIOTLB
-	if (swiotlb_nr_tbl()) {
+	if (rdev->need_swiotlb && swiotlb_nr_tbl()) {
 		return ttm_dma_populate(&gtt->ttm, rdev->dev, ctx);
 	}
 #endif
@@ -788,7 +788,7 @@ static void radeon_ttm_tt_unpopulate(str
 #endif
 
 #ifdef CONFIG_SWIOTLB
-	if (swiotlb_nr_tbl()) {
+	if (rdev->need_swiotlb && swiotlb_nr_tbl()) {
 		ttm_dma_unpopulate(&gtt->ttm, rdev->dev);
 		return;
 	}
@@ -1155,7 +1155,7 @@ static int radeon_ttm_debugfs_init(struc
 	count = ARRAY_SIZE(radeon_ttm_debugfs_list);
 
 #ifdef CONFIG_SWIOTLB
-	if (!swiotlb_nr_tbl())
+	if (!(rdev->need_swiotlb && swiotlb_nr_tbl()))
 		--count;
 #endif