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authorHeiner Kallweit <hkallweit1@gmail.com>2017-03-29 20:54:37 +0200
committerUlf Hansson <ulf.hansson@linaro.org>2017-04-18 19:18:07 +0200
commit5ef1ecf060f28ecef313b5723f1fd39bf5a35f56 (patch)
tree5548e6d502bbb2b22a9cac9c9b07da93da286fc8
parent4f7d029b9bf009fbee76bb10c0c4351a1870d2f3 (diff)
mmc: sdio: fix alignment issue in struct sdio_func
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>
-rw-r--r--drivers/mmc/core/sdio_bus.c12
-rw-r--r--include/linux/mmc/sdio_func.h2
2 files changed, 12 insertions, 2 deletions
diff --git a/drivers/mmc/core/sdio_bus.c b/drivers/mmc/core/sdio_bus.c
index e992a7f8a16f..2b32b88949ba 100644
--- a/drivers/mmc/core/sdio_bus.c
+++ b/drivers/mmc/core/sdio_bus.c
@@ -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);
diff --git a/include/linux/mmc/sdio_func.h b/include/linux/mmc/sdio_func.h
index aab032a6ae61..97ca105347a6 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; /* DMA:able scratch buffer */
unsigned num_info; /* number of info strings */
const char **info; /* info strings */