From mboxrd@z Thu Jan 1 00:00:00 1970 From: hkallweit1@gmail.com (Heiner Kallweit) Date: Wed, 29 Mar 2017 22:56:50 +0200 Subject: [PATCH v2] mmc: sdio: fix alignment issue in struct sdio_func Message-ID: <3a6258f3-35e3-e2f5-aa6b-e509f603fa45@gmail.com> To: linus-amlogic@lists.infradead.org List-Id: linus-amlogic.lists.infradead.org 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