drm/amdgpu: only enable swiotlb alloc when need v2

get the max io mapping address of system memory to see if it is over
our card accessing range.
v2: move checking later

Signed-off-by: Chunming Zhou <[e-mail]>
Reviewed-by: Monk Liu <[e-mail]>
Reviewed-by: Christian König <[e-mail]>
Signed-off-by: Alex Deucher <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]

drivers/gpu/drm/amd/amdgpu/amdgpu.h

···
 	const struct amdgpu_asic_funcs	*asic_funcs;
 	bool				shutdown;
 	bool				need_dma32;
+	bool				need_swiotlb;
 	bool				accel_working;
 	struct work_struct		reset_work;
 	struct notifier_block		acpi_nb;

drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c

···
 	}
 
 #ifdef CONFIG_SWIOTLB
-	if (swiotlb_nr_tbl()) {
+	if (adev->need_swiotlb && swiotlb_nr_tbl()) {
 		return ttm_dma_populate(&gtt->ttm, adev->dev, ctx);
 	}
 #endif
···
 	adev = amdgpu_ttm_adev(ttm->bdev);
 
 #ifdef CONFIG_SWIOTLB
-	if (swiotlb_nr_tbl()) {
+	if (adev->need_swiotlb && swiotlb_nr_tbl()) {
 		ttm_dma_unpopulate(&gtt->ttm, adev->dev);
 		return;
 	}
···
 	count = ARRAY_SIZE(amdgpu_ttm_debugfs_list);
 
 #ifdef CONFIG_SWIOTLB
-	if (!swiotlb_nr_tbl())
+	if (!(adev->need_swiotlb && swiotlb_nr_tbl()))
 		--count;
 #endif
 

drivers/gpu/drm/amd/amdgpu/gmc_v6_0.c

···
  */
 #include <linux/firmware.h>
 #include <drm/drmP.h>
+#include <drm/drm_cache.h>
 #include "amdgpu.h"
 #include "gmc_v6_0.h"
 #include "amdgpu_ucode.h"
···
 		pci_set_consistent_dma_mask(adev->pdev, DMA_BIT_MASK(32));
 		dev_warn(adev->dev, "amdgpu: No coherent DMA available.\n");
 	}
+	adev->need_swiotlb = drm_get_max_iomem() > ((u64)1 << dma_bits);
 
 	r = gmc_v6_0_init_microcode(adev);
 	if (r) {

drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c

···
  */
 #include <linux/firmware.h>
 #include <drm/drmP.h>
+#include <drm/drm_cache.h>
 #include "amdgpu.h"
 #include "cikd.h"
 #include "cik.h"
···
 		pci_set_consistent_dma_mask(adev->pdev, DMA_BIT_MASK(32));
 		pr_warn("amdgpu: No coherent DMA available\n");
 	}
+	adev->need_swiotlb = drm_get_max_iomem() > ((u64)1 << dma_bits);
 
 	r = gmc_v7_0_init_microcode(adev);
 	if (r) {

drivers/gpu/drm/amd/amdgpu/gmc_v8_0.c

···
  */
 #include <linux/firmware.h>
 #include <drm/drmP.h>
+#include <drm/drm_cache.h>
 #include "amdgpu.h"
 #include "gmc_v8_0.h"
 #include "amdgpu_ucode.h"
···
 	 */
 	adev->need_dma32 = false;
 	dma_bits = adev->need_dma32 ? 32 : 40;
+	adev->need_swiotlb = drm_get_max_iomem() > ((u64)1 << dma_bits);
 	r = pci_set_dma_mask(adev->pdev, DMA_BIT_MASK(dma_bits));
 	if (r) {
 		adev->need_dma32 = true;
···
 		pci_set_consistent_dma_mask(adev->pdev, DMA_BIT_MASK(32));
 		pr_warn("amdgpu: No coherent DMA available\n");
 	}
+	adev->need_swiotlb = drm_get_max_iomem() > ((u64)1 << dma_bits);
 
 	r = gmc_v8_0_init_microcode(adev);
 	if (r) {

drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c

···
  *
  */
 #include <linux/firmware.h>
+#include <drm/drm_cache.h>
 #include "amdgpu.h"
 #include "gmc_v9_0.h"
 #include "amdgpu_atomfirmware.h"
···
 		pci_set_consistent_dma_mask(adev->pdev, DMA_BIT_MASK(32));
 		printk(KERN_WARNING "amdgpu: No coherent DMA available.\n");
 	}
+	adev->need_swiotlb = drm_get_max_iomem() > ((u64)1 << dma_bits);
 
 	r = gmc_v9_0_mc_init(adev);
 	if (r)