| Message ID | m237dv7s83.fsf@baylibre.com (mailing list archive) |
|---|---|
| State | Not Applicable |
| Headers | show |
Am 29.03.2017 um 22:17 schrieb Kevin Hilman: > Heiner Kallweit <hkallweit1@gmail.com> writes: > >> 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. >> When testing switching to descriptor chain mode in meson-gx driver >> SDIO is broken therefore. Fix this by allocating the small DMA buffer >> separately as kmalloc ensures that the returned memory area is >> properly aligned for every basic data type. >> >> Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com> >> Tested-by: Helmut Klein <hgkr.klein@gmail.com> > > This should work too, without the need to do a tiny kmalloc. > > diff --git a/include/linux/mmc/sdio_func.h b/include/linux/mmc/sdio_func.h > index aab032a6ae61..071addf23931 100644 > --- a/include/linux/mmc/sdio_func.h > +++ b/include/linux/mmc/sdio_func.h > @@ -53,7 +53,7 @@ struct sdio_func { > unsigned int state; /* function state */ > #define SDIO_STATE_PRESENT (1<<0) /* present in sysfs */ > > - u8 tmpbuf[4]; /* DMA:able scratch buffer */ > + u8 tmpbuf[4] __aligned(8); /* DMA:able scratch buffer */ > Yes, that's possible too. Actually I wasn't 100% sure whether the alignment is applied to each member of the array or the array itself. But after a small test it seems to be applied to the array. So let's go with this version, thanks for the hint. Heiner > unsigned num_info; /* number of info strings */ > const char **info; /* info strings */ > > Kevin >
diff --git a/include/linux/mmc/sdio_func.h b/include/linux/mmc/sdio_func.h index aab032a6ae61..071addf23931 100644 --- a/include/linux/mmc/sdio_func.h +++ b/include/linux/mmc/sdio_func.h @@ -53,7 +53,7 @@ struct sdio_func { unsigned int state; /* function state */ #define SDIO_STATE_PRESENT (1<<0) /* present in sysfs */ - u8 tmpbuf[4]; /* DMA:able scratch buffer */ + u8 tmpbuf[4] __aligned(8); /* DMA:able scratch buffer */ unsigned num_info; /* number of info strings */ const char **info; /* info strings */