[PATCH 09/11] spi: airoha: buffer must be 0xff-ed before writing

[Mikhail Kshevetskiy]

During writing, the entire flash page (including OOB) will be updated
with the values from the temporary buffer, so we need to fill the
untouched areas of the buffer with 0xff value to prevent accidental
data overwriting.

Signed-off-by: Mikhail Kshevetskiy <mikhail.kshevetskiy at iopsys.eu>
---
 drivers/spi/airoha_snfi_spi.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/spi/airoha_snfi_spi.c b/drivers/spi/airoha_snfi_spi.c
index f25c5df5783..9fc44e7088a 100644
--- a/drivers/spi/airoha_snfi_spi.c
+++ b/drivers/spi/airoha_snfi_spi.c
@@ -764,7 +764,11 @@ static ssize_t airoha_snand_dirmap_write(struct spi_mem_dirmap_desc *desc,
 		return -EOPNOTSUPP;
 	}
 
+	if (offs > 0)
+		memset(txrx_buf, 0xff, offs);
 	memcpy(txrx_buf + offs, buf, len);
+	if (bytes > offs + len)
+		memset(txrx_buf + offs + len, 0xff, bytes - offs - len);
 
 	err = airoha_snand_set_mode(priv, SPI_MODE_DMA);
 	if (err < 0)
-- 
2.51.0