From: Lucas Stach <l.stach@pengutronix.de>
Date: Fri, 9 Mar 2018 12:53:34 +0100
Subject: drm/etnaviv: remove cycling through MMU address space
Git-commit: ccae45928fc43d78d6ba7d0c6965b142c922a446
Patch-mainline: v4.18-rc1
References: FATE#326289 FATE#326079 FATE#326049 FATE#322398 FATE#326166

This was useful on MMUv1 GPUs, which don't generate proper faults,
when the GPU write caches weren't fully understood and not properly
handled by the kernel driver. As this has been fixed for quite some
time, the cycling though the MMU address space needlessly spreads
out the MMU mappings.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Acked-by: Petr Tesarik <ptesarik@suse.com>
---
 drivers/gpu/drm/etnaviv/etnaviv_mmu.c |   16 +---------------
 drivers/gpu/drm/etnaviv/etnaviv_mmu.h |    1 -
 2 files changed, 1 insertion(+), 16 deletions(-)

--- a/drivers/gpu/drm/etnaviv/etnaviv_mmu.c
+++ b/drivers/gpu/drm/etnaviv/etnaviv_mmu.c
@@ -162,22 +162,10 @@ static int etnaviv_iommu_find_iova(struc
 		bool found;
 
 		ret = drm_mm_insert_node_in_range(&mmu->mm, node,
-						  size, 0, 0,
-						  mmu->last_iova, U64_MAX,
-						  mode);
+						  size, 0, 0, 0, U64_MAX, mode);
 		if (ret != -ENOSPC)
 			break;
 
-		/*
-		 * If we did not search from the start of the MMU region,
-		 * try again in case there are free slots.
-		 */
-		if (mmu->last_iova) {
-			mmu->last_iova = 0;
-			mmu->need_flush = true;
-			continue;
-		}
-
 		/* Try to retire some entries */
 		drm_mm_scan_init(&scan, &mmu->mm, size, 0, 0, mode);
 
@@ -274,7 +262,6 @@ int etnaviv_iommu_map_gem(struct etnaviv
 	if (ret < 0)
 		goto unlock;
 
-	mmu->last_iova = node->start + etnaviv_obj->base.size;
 	mapping->iova = node->start;
 	ret = etnaviv_iommu_map(mmu, node->start, sgt, etnaviv_obj->base.size,
 				ETNAVIV_PROT_READ | ETNAVIV_PROT_WRITE);
@@ -381,7 +368,6 @@ int etnaviv_iommu_get_suballoc_va(struct
 			mutex_unlock(&mmu->lock);
 			return ret;
 		}
-		mmu->last_iova = vram_node->start + size;
 		gpu->mmu->need_flush = true;
 		mutex_unlock(&mmu->lock);
 
--- a/drivers/gpu/drm/etnaviv/etnaviv_mmu.h
+++ b/drivers/gpu/drm/etnaviv/etnaviv_mmu.h
@@ -59,7 +59,6 @@ struct etnaviv_iommu {
 	struct mutex lock;
 	struct list_head mappings;
 	struct drm_mm mm;
-	u32 last_iova;
 	bool need_flush;
 };