From: Russell King - ARM Linux Subject: Re: [PATCH 1/3] crypto: marvell/cesa - replace dma_to_phys with dma_map_single Date: Thu, 17 Mar 2016 22:54:59 +0000 Message-ID: <20160317225459.GA19428@n2100.arm.linux.org.uk> References: <1458252137-24497-1-git-send-email-okaya@codeaurora.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-arm-kernel@lists.infradead.org, timur@codeaurora.org, cov@codeaurora.org, nwatters@codeaurora.org, Boris Brezillon , Herbert Xu , Arnaud Ebalard , linux-kernel@vger.kernel.org, linux-crypto@vger.kernel.org, "David S. Miller" To: Sinan Kaya Return-path: Received: from pandora.arm.linux.org.uk ([78.32.30.218]:42270 "EHLO pandora.arm.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1031637AbcCQWz0 (ORCPT ); Thu, 17 Mar 2016 18:55:26 -0400 Content-Disposition: inline In-Reply-To: <1458252137-24497-1-git-send-email-okaya@codeaurora.org> Sender: linux-crypto-owner@vger.kernel.org List-ID: On Thu, Mar 17, 2016 at 06:02:15PM -0400, Sinan Kaya wrote: > Getting ready to remove dma_to_phys API. Drivers should not be > using this API for DMA operations. Instead, they should go > through the dma_map or dma_alloc APIs. > > Signed-off-by: Sinan Kaya > --- > drivers/crypto/marvell/cesa.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/crypto/marvell/cesa.c b/drivers/crypto/marvell/cesa.c > index c0656e7..52ddfa4 100644 > --- a/drivers/crypto/marvell/cesa.c > +++ b/drivers/crypto/marvell/cesa.c > @@ -350,8 +350,8 @@ static int mv_cesa_get_sram(struct platform_device *pdev, int idx) > if (IS_ERR(engine->sram)) > return PTR_ERR(engine->sram); > > - engine->sram_dma = phys_to_dma(cesa->dev, > - (phys_addr_t)res->start); > + engine->sram_dma = dma_map_single(cesa->dev, engine->sram, > + DMA_TO_DEVICE); Documentation/DMA-API.txt dma_addr_t dma_map_single(struct device *dev, void *cpu_addr, size_t size, enum dma_data_direction direction) Notes: Not all memory regions in a machine can be mapped by this API. Further, contiguous kernel virtual space may not be contiguous as physical memory. Since this API does not provide any scatter/gather capability, it will fail if the user tries to map a non-physically contiguous piece of memory. For this reason, memory to be mapped by this API should be obtained from sources which guarantee it to be physically contiguous (like kmalloc). Specifically, ioremapped memory will *not* work as you expect with dma_map_single(). -- RMK's Patch system: http://www.arm.linux.org.uk/developer/patches/ FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up according to speedtest.net.