Re: [PATCH V3 11/16] drm/radeon: Make radeon card usable for Loongson.

[Lucas Stach <dev@lynxeye.de>]

Hello Huacai,

Am Freitag, den 22.06.2012, 11:01 +0800 schrieb Huacai Chen:
> 1, Handle io prot correctly for MIPS.
> 2, Define SAREA_MAX as the size of one page.
> 3, Don't use swiotlb on Loongson machines (Loonson need swioitlb, but
>    when use swiotlb, GPU reset occurs at resume from suspend).
> 
I still think this is wrong. You say Loongson needs SWIOTLB, but when
it's actually used you ignore it in the radeon driver code.

I looked up why you are using SWIOTLB and I don't agree with you that it
is needed. SWIOTLB just gives you bounce pages for DMA memory above
DMA32 and therefore papers over your >4GB DMA platform bug in some
cases, while hurting performance.

Please fix your DMA platform code so that region DMA is an alias for
region DMA32. It should allow you to drop all those ugly workarounds.

> Signed-off-by: Huacai Chen <chenhc@lemote.com>
> Signed-off-by: Hongliang Tao <taohl@lemote.com>
> Signed-off-by: Hua Yan <yanh@lemote.com>
> Reviewed-by: Michel Dänzer <michel@daenzer.net>
> Reviewed-by: Alex Deucher <alexdeucher@gmail.com>
> Reviewed-by: Lucas Stach <dev@lynxeye.de>
> Reviewed-by: j.glisse <j.glisse@gmail.com>

You should probably only stick this tag on your patches after the people
you are naming explicitly gave their r-b for a specific version of a
patch.

Thanks,
Lucas
> Cc: dri-devel@lists.freedesktop.org
> ---
>  drivers/gpu/drm/drm_vm.c            |    2 +-
>  drivers/gpu/drm/radeon/radeon_ttm.c |    6 +++---
>  drivers/gpu/drm/ttm/ttm_bo_util.c   |    2 +-
>  include/drm/drm_sarea.h             |    2 ++
>  4 files changed, 7 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_vm.c b/drivers/gpu/drm/drm_vm.c
> index 961ee08..3f06166 100644
> --- a/drivers/gpu/drm/drm_vm.c
> +++ b/drivers/gpu/drm/drm_vm.c
> @@ -62,7 +62,7 @@ static pgprot_t drm_io_prot(uint32_t map_type, struct vm_area_struct *vma)
>  		tmp = pgprot_writecombine(tmp);
>  	else
>  		tmp = pgprot_noncached(tmp);
> -#elif defined(__sparc__) || defined(__arm__)
> +#elif defined(__sparc__) || defined(__arm__) || defined(__mips__)
>  	tmp = pgprot_noncached(tmp);
>  #endif
>  	return tmp;
> diff --git a/drivers/gpu/drm/radeon/radeon_ttm.c b/drivers/gpu/drm/radeon/radeon_ttm.c
> index c94a225..f49bdd1 100644
> --- a/drivers/gpu/drm/radeon/radeon_ttm.c
> +++ b/drivers/gpu/drm/radeon/radeon_ttm.c
> @@ -630,7 +630,7 @@ static int radeon_ttm_tt_populate(struct ttm_tt *ttm)
>  	}
>  #endif
>  
> -#ifdef CONFIG_SWIOTLB
> +#if defined(CONFIG_SWIOTLB) && !defined(CONFIG_CPU_LOONGSON3)
>  	if (swiotlb_nr_tbl()) {
>  		return ttm_dma_populate(&gtt->ttm, rdev->dev);
>  	}
> @@ -676,7 +676,7 @@ static void radeon_ttm_tt_unpopulate(struct ttm_tt *ttm)
>  	}
>  #endif
>  
> -#ifdef CONFIG_SWIOTLB
> +#if defined(CONFIG_SWIOTLB) && !defined(CONFIG_CPU_LOONGSON3)
>  	if (swiotlb_nr_tbl()) {
>  		ttm_dma_unpopulate(&gtt->ttm, rdev->dev);
>  		return;
> @@ -906,7 +906,7 @@ static int radeon_ttm_debugfs_init(struct radeon_device *rdev)
>  	radeon_mem_types_list[i].show = &ttm_page_alloc_debugfs;
>  	radeon_mem_types_list[i].driver_features = 0;
>  	radeon_mem_types_list[i++].data = NULL;
> -#ifdef CONFIG_SWIOTLB
> +#if defined(CONFIG_SWIOTLB) && !defined(CONFIG_CPU_LOONGSON3)
>  	if (swiotlb_nr_tbl()) {
>  		sprintf(radeon_mem_types_names[i], "ttm_dma_page_pool");
>  		radeon_mem_types_list[i].name = radeon_mem_types_names[i];
> diff --git a/drivers/gpu/drm/ttm/ttm_bo_util.c b/drivers/gpu/drm/ttm/ttm_bo_util.c
> index f8187ea..0df71ea 100644
> --- a/drivers/gpu/drm/ttm/ttm_bo_util.c
> +++ b/drivers/gpu/drm/ttm/ttm_bo_util.c
> @@ -472,7 +472,7 @@ pgprot_t ttm_io_prot(uint32_t caching_flags, pgprot_t tmp)
>  	else
>  		tmp = pgprot_noncached(tmp);
>  #endif
> -#if defined(__sparc__)
> +#if defined(__sparc__) || defined(__mips__)
>  	if (!(caching_flags & TTM_PL_FLAG_CACHED))
>  		tmp = pgprot_noncached(tmp);
>  #endif
> diff --git a/include/drm/drm_sarea.h b/include/drm/drm_sarea.h
> index ee5389d..1d1a858 100644
> --- a/include/drm/drm_sarea.h
> +++ b/include/drm/drm_sarea.h
> @@ -37,6 +37,8 @@
>  /* SAREA area needs to be at least a page */
>  #if defined(__alpha__)
>  #define SAREA_MAX                       0x2000U
> +#elif defined(__mips__)
> +#define SAREA_MAX                       0x4000U
>  #elif defined(__ia64__)
>  #define SAREA_MAX                       0x10000U	/* 64kB */
>  #else