[PATCH v1] mtd: rawnand: meson: fix unaligned DMA buffers handling

[Arseniy Krasnov]

Meson NAND controller requires 8 bytes alignment for DMA addresses,
otherwise it "aligns" passed address by itself thus accessing invalid
location in the provided buffer. This patch makes unaligned buffers to
be reallocated to become valid.

Fixes: 8fae856c5350 ("mtd: rawnand: meson: add support for Amlogic NAND flash controller")
Cc: <Stable at vger.kernel.org>
Signed-off-by: Arseniy Krasnov <AVKrasnov at sberdevices.ru>
---
 drivers/mtd/nand/raw/meson_nand.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/mtd/nand/raw/meson_nand.c b/drivers/mtd/nand/raw/meson_nand.c
index c5628f7ac3b1..aa2b64dde74b 100644
--- a/drivers/mtd/nand/raw/meson_nand.c
+++ b/drivers/mtd/nand/raw/meson_nand.c
@@ -77,6 +77,7 @@
 #define GENCMDIADDRH(aih, addr)		((aih) | (((addr) >> 16) & 0xffff))
 
 #define DMA_DIR(dir)		((dir) ? NFC_CMD_N2M : NFC_CMD_M2N)
+#define DMA_ADDR_ALIGN		8
 
 #define ECC_CHECK_RETURN_FF	(-1)
 
@@ -1001,6 +1002,9 @@ static int meson_nfc_read_page_hwecc(struct nand_chip *nand, u8 *buf,
 
 static bool meson_nfc_is_buffer_dma_safe(const void *buffer)
 {
+	if ((uintptr_t)buffer % DMA_ADDR_ALIGN)
+		return false;
+
 	if (virt_addr_valid(buffer) && (!object_is_on_stack(buffer)))
 		return true;
 	return false;
-- 
2.35.0