From mboxrd@z Thu Jan 1 00:00:00 1970 From: Heiner Kallweit Subject: [PATCH v2] mmc: sdio: fix alignment issue in struct sdio_func Date: Wed, 29 Mar 2017 22:56:50 +0200 Message-ID: <3a6258f3-35e3-e2f5-aa6b-e509f603fa45@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: Received: from mail-wr0-f193.google.com ([209.85.128.193]:32801 "EHLO mail-wr0-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932509AbdC2U5R (ORCPT ); Wed, 29 Mar 2017 16:57:17 -0400 Received: by mail-wr0-f193.google.com with SMTP id u18so6494592wrc.0 for ; Wed, 29 Mar 2017 13:57:10 -0700 (PDT) Sender: linux-mmc-owner@vger.kernel.org List-Id: linux-mmc@vger.kernel.org To: Ulf Hansson Cc: "linux-mmc@vger.kernel.org" , linux-amlogic@lists.infradead.org, Helmut Klein , Kevin Hilman Certain 64-bit systems (e.g. Amlogic Meson GX) require buffers to be used for DMA to be 8-byte-aligned. struct sdio_func has an embedded small DMA buffer not meeting this requirement. Testing an extension to meson-gx driver for switching to descriptor chain mode broke SDIO therefore. Aligning tmpbuf to a 8-byte boundary fixed the driver behavior. Signed-off-by: Heiner Kallweit Tested-by: Helmut Klein --- v2: - switch to much simpler version as suggested by Kevin Hilman - adjust commit message --- include/linux/mmc/sdio_func.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/include/linux/mmc/sdio_func.h b/include/linux/mmc/sdio_func.h index aab032a6..65d90f76 100644 --- a/include/linux/mmc/sdio_func.h +++ b/include/linux/mmc/sdio_func.h @@ -53,7 +53,8 @@ struct sdio_func { unsigned int state; /* function state */ #define SDIO_STATE_PRESENT (1<<0) /* present in sysfs */ - u8 tmpbuf[4]; /* DMA:able scratch buffer */ + /* take care of proper alignment for DMA on certain 64-bit systems */ + u8 __aligned(8) tmpbuf[4]; /* DMA:able scratch buffer */ unsigned num_info; /* number of info strings */ const char **info; /* info strings */ -- 2.12.1