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mmc: sdio: fix alignment issue in struct sdio_func

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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>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
This commit is contained in:
Heiner Kallweit 2017-03-29 20:54:37 +02:00 committed by Ulf Hansson
parent 4f7d029b9b
commit 5ef1ecf060
2 changed files with 12 additions and 2 deletions
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12
drivers/mmc/core/sdio_bus.c
View File

@ -267,7 +267,7 @@ static void sdio_release_func(struct device *dev)
sdio_free_func_cis(func);
kfree(func->info);
kfree(func->tmpbuf);
kfree(func);
}
@ -282,6 +282,16 @@ struct sdio_func *sdio_alloc_func(struct mmc_card *card)
if (!func)
return ERR_PTR(-ENOMEM);
/*
* allocate buffer separately to make sure it's properly aligned for
* DMA usage (incl. 64 bit DMA)
*/
func->tmpbuf = kmalloc(4, GFP_KERNEL);
if (!func->tmpbuf) {
kfree(func);
return ERR_PTR(-ENOMEM);
}
func->card = card;
device_initialize(&func->dev);

2
include/linux/mmc/sdio_func.h
View File

@ -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; /* DMA:able scratch buffer */
unsigned num_info; /* number of info strings */
const char **info; /* info strings */