[PATCH v6 02/17] dma: Allow dma_get_cache_alignment() to be overridden by the arch code

From: Catalin Marinas <catalin.marinas@arm.com>
To: Linus Torvalds <torvalds@linux-foundation.org>,
	Christoph Hellwig <hch@lst.de>,
	Robin Murphy <robin.murphy@arm.com>
Cc: Arnd Bergmann <arnd@arndb.de>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Will Deacon <will@kernel.org>, Marc Zyngier <maz@kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Herbert Xu <herbert@gondor.apana.org.au>,
	Ard Biesheuvel <ardb@kernel.org>,
	Isaac Manjarres <isaacmanjarres@google.com>,
	Saravana Kannan <saravanak@google.com>,
	Alasdair Kergon <agk@redhat.com>, Daniel Vetter <daniel@ffwll.ch>,
	Joerg Roedel <joro@8bytes.org>, Mark Brown <broonie@kernel.org>,
	Mike Snitzer <snitzer@kernel.org>,
	"Rafael J. Wysocki" <rafael@kernel.org>,
	Jonathan Cameron <jic23@kernel.org>,
	linux-mm@kvack.org, iommu@lists.linux.dev,
	linux-arm-kernel@lists.infradead.org
Subject: [PATCH v6 02/17] dma: Allow dma_get_cache_alignment() to be overridden by the arch code
Date: Wed, 31 May 2023 16:48:21 +0100	[thread overview]
Message-ID: <20230531154836.1366225-3-catalin.marinas@arm.com> (raw)
In-Reply-To: <20230531154836.1366225-1-catalin.marinas@arm.com>

On arm64, ARCH_DMA_MINALIGN is larger than most cache line size
configurations deployed. Allow an architecture to override
dma_get_cache_alignment() in order to return a run-time probed value
(e.g. cache_line_size()).

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Will Deacon <will@kernel.org>
---
 include/linux/dma-mapping.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index 3288a1339271..c41019289223 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -543,6 +543,7 @@ static inline int dma_set_min_align_mask(struct device *dev,
 	return 0;
 }
 
+#ifndef dma_get_cache_alignment
 static inline int dma_get_cache_alignment(void)
 {
 #ifdef ARCH_HAS_DMA_MINALIGN
@@ -550,6 +551,7 @@ static inline int dma_get_cache_alignment(void)
 #endif
 	return 1;
 }
+#endif
 
 static inline void *dmam_alloc_coherent(struct device *dev, size_t size,
 		dma_addr_t *dma_handle, gfp_t gfp)
