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From:   Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
To:     hch@lst.de, Robin Murphy <robin.murphy@arm.com>,
        David Rientjes <rientjes@google.com>,
        iommu@lists.linux-foundation.org,
        Marek Szyprowski <m.szyprowski@samsung.com>
Cc:     linux-rpi-kernel@lists.infradead.org, jeremy.linton@arm.com,
        Nicolas Saenz Julienne <nsaenzjulienne@suse.de>,
        linux-kernel@vger.kernel.org
Subject: [PATCH 1/4] dma-direct: Provide function to check physical memory area validity
Date:   Thu,  9 Jul 2020 18:19:01 +0200
Message-Id: <20200709161903.26229-2-nsaenzjulienne@suse.de>
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dma_coherent_ok() checks if a physical memory area fits a device's DMA
constraints.

Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
---
 include/linux/dma-direct.h | 1 +
 kernel/dma/direct.c        | 2 +-
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/include/linux/dma-direct.h b/include/linux/dma-direct.h
index cdfa400f89b3..cb23a8305132 100644
--- a/include/linux/dma-direct.h
+++ b/include/linux/dma-direct.h
@@ -69,6 +69,7 @@ static inline bool dma_capable(struct device *dev, dma_addr_t addr, size_t size,
 u64 dma_direct_get_required_mask(struct device *dev);
 gfp_t dma_direct_optimal_gfp_mask(struct device *dev, u64 dma_mask,
 				  u64 *phys_mask);
+bool dma_coherent_ok(struct device *dev, phys_addr_t phys, size_t size);
 void *dma_direct_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle,
 		gfp_t gfp, unsigned long attrs);
 void dma_direct_free(struct device *dev, size_t size, void *cpu_addr,
diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index 93f578a8e613..4de864cacd22 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -70,7 +70,7 @@ gfp_t dma_direct_optimal_gfp_mask(struct device *dev, u64 dma_mask,
 	return 0;
 }
 
-static bool dma_coherent_ok(struct device *dev, phys_addr_t phys, size_t size)
+bool dma_coherent_ok(struct device *dev, phys_addr_t phys, size_t size)
 {
 	return phys_to_dma_direct(dev, phys) + size - 1 <=
 			min_not_zero(dev->coherent_dma_mask, dev->bus_dma_limit);
-- 
2.27.0