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From: Christoph Hellwig <hch@lst.de>
To: iommu@lists.linux-foundation.org
Cc: Shawn Anastasio <shawn@anastas.io>,
	Michael Ellerman <mpe@ellerman.id.au>,
	Russell King <linux@armlinux.org.uk>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>,
	Robin Murphy <robin.murphy@arm.com>,
	Paul Burton <paul.burton@mips.com>,
	James Hogan <jhogan@kernel.org>,
	linuxppc-dev@lists.ozlabs.org, linux-mips@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org
Subject: [PATCH 2/2] MIPS: remove support for DMA_ATTR_WRITE_COMBINE
Date: Wed,  7 Aug 2019 09:16:02 +0300	[thread overview]
Message-ID: <20190807061602.31217-3-hch@lst.de> (raw)
In-Reply-To: <20190807061602.31217-1-hch@lst.de>

Mips uses the KSEG1 kernel memory segment to map dma coherent
allocations for non-coherent devices as uncacheable, and does not have
any kind of special support for DMA_ATTR_WRITE_COMBINE in the allocation
path.  Thus supporting DMA_ATTR_WRITE_COMBINE in dma_mmap_attrs will
lead to multiple mappings with different caching attributes.

Fixes: 8c172467be36 ("MIPS: Add implementation of dma_map_ops.mmap()")
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 arch/mips/Kconfig              | 1 -
 arch/mips/mm/dma-noncoherent.c | 8 --------
 2 files changed, 9 deletions(-)

diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index d50fafd7bf3a..86e6760ef0d0 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -1119,7 +1119,6 @@ config DMA_PERDEV_COHERENT
 
 config DMA_NONCOHERENT
 	bool
-	select ARCH_HAS_DMA_MMAP_PGPROT
 	select ARCH_HAS_SYNC_DMA_FOR_DEVICE
 	select ARCH_HAS_UNCACHED_SEGMENT
 	select NEED_DMA_MAP_STATE
diff --git a/arch/mips/mm/dma-noncoherent.c b/arch/mips/mm/dma-noncoherent.c
index ed56c6fa7be2..1d4d57dd9acf 100644
--- a/arch/mips/mm/dma-noncoherent.c
+++ b/arch/mips/mm/dma-noncoherent.c
@@ -65,14 +65,6 @@ long arch_dma_coherent_to_pfn(struct device *dev, void *cpu_addr,
 	return page_to_pfn(virt_to_page(cached_kernel_address(cpu_addr)));
 }
 
-pgprot_t arch_dma_mmap_pgprot(struct device *dev, pgprot_t prot,
-		unsigned long attrs)
-{
-	if (attrs & DMA_ATTR_WRITE_COMBINE)
-		return pgprot_writecombine(prot);
-	return pgprot_noncached(prot);
-}
-
 static inline void dma_sync_virt(void *addr, size_t size,
 		enum dma_data_direction dir)
 {
-- 
2.20.1


  parent reply	other threads:[~2019-08-07  6:16 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-07  6:16 fix default dma_mmap_* pgprot v3 Christoph Hellwig
2019-08-07  6:16 ` [PATCH 1/2] dma-mapping: fix page attributes for dma_mmap_* Christoph Hellwig
2019-08-07  6:16 ` Christoph Hellwig [this message]
2019-09-18 19:50   ` [PATCH 2/2] MIPS: remove support for DMA_ATTR_WRITE_COMBINE Maciej W. Rozycki
  -- strict thread matches above, loose matches on Subject: below --
2019-08-05  8:01 fix default dma_mmap_* pgprot v2 Christoph Hellwig
2019-08-05  8:01 ` [PATCH 2/2] MIPS: remove support for DMA_ATTR_WRITE_COMBINE Christoph Hellwig
2019-08-05  8:06   ` Sergei Shtylyov

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