Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
From:   Sasha Levin <Alexander.Levin@microsoft.com>
To:     "stable@vger.kernel.org" <stable@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
CC:     Vladimir Murzin <vladimir.murzin@arm.com>,
        Joerg Roedel <jroedel@suse.de>,
        Christian Borntraeger <borntraeger@de.ibm.com>,
        Christoph Hellwig <hch@lst.de>,
        Sasha Levin <Alexander.Levin@microsoft.com>
Subject: [PATCH AUTOSEL for 4.9 162/293] dma: Take into account dma_pfn_offset
Thread-Topic: [PATCH AUTOSEL for 4.9 162/293] dma: Take into account
 dma_pfn_offset
Thread-Index: AQHTz5kxsxKS10aH9keVfokOyy1kRw==
Date:   Mon, 9 Apr 2018 00:25:00 +0000
Message-ID: <20180409002239.163177-162-alexander.levin@microsoft.com>
References: <20180409002239.163177-1-alexander.levin@microsoft.com>
In-Reply-To: <20180409002239.163177-1-alexander.levin@microsoft.com>
Accept-Language: en-US
Content-Language: en-US
received-spf: None (protection.outlook.com: microsoft.com does not designate
 permitted sender hosts)
spamdiagnosticoutput: 1:99
spamdiagnosticmetadata: NSPM
Content-Type: text/plain; charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable
MIME-Version: 1.0
X-MS-Exchange-CrossTenant-Network-Message-Id: c6268656-e28c-4763-602f-08d59db132ac
X-MS-Exchange-CrossTenant-originalarrivaltime: 09 Apr 2018 00:25:00.1907
 (UTC)
X-MS-Exchange-CrossTenant-fromentityheader: Hosted
X-MS-Exchange-CrossTenant-id: 72f988bf-86f1-41af-91ab-2d7cd011db47
X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM5PR2101MB0917
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

From: Vladimir Murzin <vladimir.murzin@arm.com>

[ Upstream commit 25f1e18870881f3366a5abec27b651983ce9032c ]

Even though dma-noop-ops assumes 1:1 memory mapping DMA memory range
can be different to RAM. For example, ARM STM32F4 MCU offers the
possibility to remap SDRAM from 0xc000_0000 to 0x0 to get CPU
performance boost, but DMA continue to see SDRAM at 0xc000_0000. This
difference in mapping is handled via device-tree "dma-range" property
which leads to dev->dma_pfn_offset is set nonzero. To handle such
cases take dma_pfn_offset into account.

Cc: Joerg Roedel <jroedel@suse.de>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Reported-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>
Tested-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>
Tested-by: Andras Szemzo <sza@esh.hu>
Tested-by: Alexandre TORGUE <alexandre.torgue@st.com>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
---
 lib/dma-noop.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/lib/dma-noop.c b/lib/dma-noop.c
index 3d766e78fbe2..9a7b5ed7ceac 100644
--- a/lib/dma-noop.c
+++ b/lib/dma-noop.c
@@ -7,6 +7,7 @@
 #include <linux/mm.h>
 #include <linux/dma-mapping.h>
 #include <linux/scatterlist.h>
+#include <linux/pfn.h>
=20
 static void *dma_noop_alloc(struct device *dev, size_t size,
 			    dma_addr_t *dma_handle, gfp_t gfp,
@@ -16,7 +17,8 @@ static void *dma_noop_alloc(struct device *dev, size_t si=
ze,
=20
 	ret =3D (void *)__get_free_pages(gfp, get_order(size));
 	if (ret)
-		*dma_handle =3D virt_to_phys(ret);
+		*dma_handle =3D virt_to_phys(ret) - PFN_PHYS(dev->dma_pfn_offset);
+
 	return ret;
 }
=20
@@ -32,7 +34,7 @@ static dma_addr_t dma_noop_map_page(struct device *dev, s=
truct page *page,
 				      enum dma_data_direction dir,
 				      unsigned long attrs)
 {
-	return page_to_phys(page) + offset;
+	return page_to_phys(page) + offset - PFN_PHYS(dev->dma_pfn_offset);
 }
=20
 static int dma_noop_map_sg(struct device *dev, struct scatterlist *sgl, in=
t nents,
@@ -43,11 +45,12 @@ static int dma_noop_map_sg(struct device *dev, struct s=
catterlist *sgl, int nent
 	struct scatterlist *sg;
=20
 	for_each_sg(sgl, sg, nents, i) {
+		dma_addr_t offset =3D PFN_PHYS(dev->dma_pfn_offset);
 		void *va;
=20
 		BUG_ON(!sg_page(sg));
 		va =3D sg_virt(sg);
-		sg_dma_address(sg) =3D (dma_addr_t)virt_to_phys(va);
+		sg_dma_address(sg) =3D (dma_addr_t)virt_to_phys(va) - offset;
 		sg_dma_len(sg) =3D sg->length;
 	}
=20
--=20
2.15.1