linux-kernel - [PATCH 25/34] dma-direct: use phys_to

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Date:   Fri, 12 Jan 2018 09:42:23 +0100
From:   Christoph Hellwig <hch@....de>
To:     iommu@...ts.linux-foundation.org
Cc:     Konrad Rzeszutek Wilk <konrad@...nok.org>,
        linux-alpha@...r.kernel.org, linux-snps-arc@...ts.infradead.org,
        linux-arm-kernel@...ts.infradead.org, linux-c6x-dev@...ux-c6x.org,
        linux-cris-kernel@...s.com, linux-hexagon@...r.kernel.org,
        linux-ia64@...r.kernel.org, linux-m68k@...ts.linux-m68k.org,
        linux-metag@...r.kernel.org, Michal Simek <monstr@...str.eu>,
        linux-mips@...ux-mips.org, linux-parisc@...r.kernel.org,
        linuxppc-dev@...ts.ozlabs.org, patches@...ups.riscv.org,
        linux-s390@...r.kernel.org, linux-sh@...r.kernel.org,
        sparclinux@...r.kernel.org, Guan Xuetao <gxt@...c.pku.edu.cn>,
        x86@...nel.org, linux-arch@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH 25/34] dma-direct: use phys_to_dma

This means it uses whatever linear remapping scheme that the architecture
provides is used in the generic dma_direct ops.

Signed-off-by: Christoph Hellwig <hch@....de>
Reviewed-by: Vladimir Murzin <vladimir.murzin@....com>
---
 lib/dma-direct.c | 18 +++++++-----------
 1 file changed, 7 insertions(+), 11 deletions(-)

diff --git a/lib/dma-direct.c b/lib/dma-direct.c
index 0ec3262a3148..12ea9653781b 100644
--- a/lib/dma-direct.c
+++ b/lib/dma-direct.c
@@ -1,12 +1,11 @@
 // SPDX-License-Identifier: GPL-2.0
 /*
- *	lib/dma-noop.c
- *
- * DMA operations that map to physical addresses without flushing memory.
+ * DMA operations that map physical memory directly without using an IOMMU or
+ * flushing caches.
  */
 #include <linux/export.h>
 #include <linux/mm.h>
-#include <linux/dma-mapping.h>
+#include <linux/dma-direct.h>
 #include <linux/scatterlist.h>
 #include <linux/pfn.h>
 
@@ -17,7 +16,7 @@ static void *dma_direct_alloc(struct device *dev, size_t size,
 
 	ret = (void *)__get_free_pages(gfp, get_order(size));
 	if (ret)
-		*dma_handle = virt_to_phys(ret) - PFN_PHYS(dev->dma_pfn_offset);
+		*dma_handle = phys_to_dma(dev, virt_to_phys(ret));
 
 	return ret;
 }
@@ -32,7 +31,7 @@ static dma_addr_t dma_direct_map_page(struct device *dev, struct page *page,
 		unsigned long offset, size_t size, enum dma_data_direction dir,
 		unsigned long attrs)
 {
-	return page_to_phys(page) + offset - PFN_PHYS(dev->dma_pfn_offset);
+	return phys_to_dma(dev, page_to_phys(page)) + offset;
 }
 
 static int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl,
@@ -42,12 +41,9 @@ static int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl,
 	struct scatterlist *sg;
 
 	for_each_sg(sgl, sg, nents, i) {
-		dma_addr_t offset = PFN_PHYS(dev->dma_pfn_offset);
-		void *va;
-
 		BUG_ON(!sg_page(sg));
-		va = sg_virt(sg);
-		sg_dma_address(sg) = (dma_addr_t)virt_to_phys(va) - offset;
+
+		sg_dma_address(sg) = phys_to_dma(dev, sg_phys(sg));
 		sg_dma_len(sg) = sg->length;
 	}
 
-- 
2.14.2