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gpu: nvgpu: Remove DMA_NO_KERNEL_MAPPING WAR for coherent chips

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The commit 3fdd8e38b2 ("gpu: nvgpu: Use our own vmap() for
coherent DMA buffers") added an NVGPU_DMA_NO_KERNEL_MAPPING
flag for coherent chips to work around a memory mapping bug
suspiciously from DMA API.

However, this requires dma-mapping code of ARM64 to support
a legacy DMA_NO_KERNEL_MAPPING attribute for DMA allocation,
which will not likely get upstreamed -- it is not long-term
sustainable. So the plan is to remove this flag from ARM64
part.

The results of 3D benchmarks and GVS sanity tests show that
the system has no regressions in stability, and no mapping
issue being observed after removing this WAR. In case that
GPU code encounters mapping issue in the future, we should
fix from the general DMA API side instead.

Bug 2424160

Change-Id: Ice91f2b2c924beb2f83762cb02efbd53fe7df1c0
Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/2001294
Reviewed-by: Konsta Holtta <kholtta@nvidia.com>
GVS: Gerrit_Virtual_Submit
Reviewed-by: Alex Waterman <alexw@nvidia.com>
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>
This commit is contained in:
Nicolin Chen
2019-01-22 15:24:55 -08:00
committed by mobile promotions
parent aa025c9f28
commit 7b19a825bd
2 changed files with 4 additions and 38 deletions
Download Patch File Download Diff File Expand all files Collapse all files

30
drivers/gpu/nvgpu/os/linux/linux-dma.c
View File

@@ -1,5 +1,5 @@
/* /*
* Copyright (c) 2017-2018, NVIDIA CORPORATION. All rights reserved. * Copyright (c) 2017-2019, NVIDIA CORPORATION. All rights reserved.
* *
* This program is free software; you can redistribute it and/or modify it * This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License, * under the terms and conditions of the GNU General Public License,
@@ -194,16 +194,6 @@ int nvgpu_dma_alloc_flags_sys(struct gk20a *g, unsigned long flags,
flags |= NVGPU_DMA_FORCE_CONTIGUOUS; flags |= NVGPU_DMA_FORCE_CONTIGUOUS;
} }
/*
* WAR for IO coherent chips: the DMA API does not seem to generate
* mappings that work correctly. Unclear why - Bug ID: 2040115.
*
* Basically we just tell the DMA API not to map with NO_KERNEL_MAPPING
* and then make a vmap() ourselves.
*/
if (nvgpu_is_enabled(g, NVGPU_USE_COHERENT_SYSMEM))
flags |= NVGPU_DMA_NO_KERNEL_MAPPING;
/* /*
* Before the debug print so we see this in the total. But during * Before the debug print so we see this in the total. But during
* cleanup in the fail path this has to be subtracted. * cleanup in the fail path this has to be subtracted.
@@ -240,16 +230,6 @@ int nvgpu_dma_alloc_flags_sys(struct gk20a *g, unsigned long flags,
if (err) if (err)
goto fail_free_dma; goto fail_free_dma;
if (nvgpu_is_enabled(g, NVGPU_USE_COHERENT_SYSMEM)) {
mem->cpu_va = vmap(mem->priv.pages,
size >> PAGE_SHIFT,
0, PAGE_KERNEL);
if (!mem->cpu_va) {
err = -ENOMEM;
goto fail_free_sgt;
}
}
mem->aligned_size = size; mem->aligned_size = size;
mem->aperture = APERTURE_SYSMEM; mem->aperture = APERTURE_SYSMEM;
mem->priv.flags = flags; mem->priv.flags = flags;
@@ -258,8 +238,6 @@ int nvgpu_dma_alloc_flags_sys(struct gk20a *g, unsigned long flags,
return 0; return 0;
fail_free_sgt:
nvgpu_free_sgtable(g, &mem->priv.sgt);
fail_free_dma: fail_free_dma:
dma_free_attrs(d, size, alloc_ret, iova, NVGPU_DMA_ATTR(dma_attrs)); dma_free_attrs(d, size, alloc_ret, iova, NVGPU_DMA_ATTR(dma_attrs));
mem->cpu_va = NULL; mem->cpu_va = NULL;
@@ -364,12 +342,6 @@ void nvgpu_dma_free_sys(struct gk20a *g, struct nvgpu_mem *mem)
if (!(mem->mem_flags & NVGPU_MEM_FLAG_SHADOW_COPY) && if (!(mem->mem_flags & NVGPU_MEM_FLAG_SHADOW_COPY) &&
!(mem->mem_flags & __NVGPU_MEM_FLAG_NO_DMA) && !(mem->mem_flags & __NVGPU_MEM_FLAG_NO_DMA) &&
(mem->cpu_va || mem->priv.pages)) { (mem->cpu_va || mem->priv.pages)) {
/*
* Free side of WAR for bug 2040115.
*/
if (nvgpu_is_enabled(g, NVGPU_USE_COHERENT_SYSMEM))
vunmap(mem->cpu_va);
if (mem->priv.flags) { if (mem->priv.flags) {
NVGPU_DEFINE_DMA_ATTRS(dma_attrs); NVGPU_DEFINE_DMA_ATTRS(dma_attrs);

12
drivers/gpu/nvgpu/os/linux/nvgpu_mem.c
View File

@@ -1,5 +1,5 @@
/* /*
* Copyright (c) 2017-2018, NVIDIA CORPORATION. All rights reserved. * Copyright (c) 2017-2019, NVIDIA CORPORATION. All rights reserved.
* *
* This program is free software; you can redistribute it and/or modify it * This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License, * under the terms and conditions of the GNU General Public License,
@@ -163,14 +163,8 @@ int nvgpu_mem_create_from_mem(struct gk20a *g,
dest->skip_wmb = src->skip_wmb; dest->skip_wmb = src->skip_wmb;
dest->size = size; dest->size = size;
/* /* Re-use the CPU mapping only if the mapping was made by the DMA API */
* Re-use the CPU mapping only if the mapping was made by the DMA API. if (!(src->priv.flags & NVGPU_DMA_NO_KERNEL_MAPPING))
*
* Bug 2040115: the DMA API wrapper makes the mapping that we should
* re-use.
*/
if (!(src->priv.flags & NVGPU_DMA_NO_KERNEL_MAPPING) ||
nvgpu_is_enabled(g, NVGPU_USE_COHERENT_SYSMEM))
dest->cpu_va = src->cpu_va + (PAGE_SIZE * start_page); dest->cpu_va = src->cpu_va + (PAGE_SIZE * start_page);
dest->priv.pages = src->priv.pages + start_page; dest->priv.pages = src->priv.pages + start_page;