mtd: rawnand: meson: fix unaligned DMA buffers handling

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: 8fae856 ("mtd: rawnand: meson: add support for Amlogic NAND flash controller")
Cc: <Stable@vger.kernel.org>
Signed-off-by: Arseniy Krasnov <AVKrasnov@sberdevices.ru>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20230615080815.3291006-1-AVKrasnov@sberdevices.ru

Author: Arseniy Krasnov

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)
 
@@ -905,6 +906,9 @@ static int meson_nfc_read_oob(struct nand_chip *nand, int page)
 
 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;