[PATCH 5.4 193/222] mtd: devices: fix mchp23k256 read and write

Greg Kroah-Hartman
2020-01-22T13:28:36Z

From: Angelo Dureghello <angelo.dureghello@timesys.com>

commit 14f89e088155314d311e4d4dd9f2b4ccaeef92b2 upstream.

Due to the use of sizeof(), command size set for the spi transfer
was wrong. Driver was sending and receiving always 1 byte less
and especially on write, it was hanging.

echo -n -e "\\x1\\x2\\x3\\x4" > /dev/mtd1

And read part too now works as expected.

hexdump -C -n16 /dev/mtd1
00000000 01 02 03 04 ab f3 ad c2 ab e3 f4 36 dd 38 04 15
00000010

Fixes: 4379075a870b ("mtd: mchp23k256: Add support for mchp23lcv1024")
Signed-off-by: Angelo Dureghello <angelo.dureghello@timesys.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/mtd/devices/mchp23k256.c | 20 ++++++++++++--------
1 file changed, 12 insertions(+), 8 deletions(-)

--- a/drivers/mtd/devices/mchp23k256.c
+++ b/drivers/mtd/devices/mchp23k256.c
@@ -64,15 +64,17 @@ static int mchp23k256_write(struct mtd_i
struct spi_transfer transfer[2] = {};
struct spi_message message;
unsigned char command[MAX_CMD_SIZE];
- int ret;
+ int ret, cmd_len;

spi_message_init(&message);

+ cmd_len = mchp23k256_cmdsz(flash);
+
command[0] = MCHP23K256_CMD_WRITE;
mchp23k256_addr2cmd(flash, to, command);

transfer[0].tx_buf = command;
- transfer[0].len = mchp23k256_cmdsz(flash);
+ transfer[0].len = cmd_len;
spi_message_add_tail(&transfer[0], &message);

transfer[1].tx_buf = buf;
@@ -88,8 +90,8 @@ static int mchp23k256_write(struct mtd_i
if (ret)
return ret;

- if (retlen && message.actual_length > sizeof(command))
- *retlen += message.actual_length - sizeof(command);
+ if (retlen && message.actual_length > cmd_len)
+ *retlen += message.actual_length - cmd_len;

return 0;
}
@@ -101,16 +103,18 @@ static int mchp23k256_read(struct mtd_in
struct spi_transfer transfer[2] = {};
struct spi_message message;
unsigned char command[MAX_CMD_SIZE];
- int ret;
+ int ret, cmd_len;

spi_message_init(&message);

+ cmd_len = mchp23k256_cmdsz(flash);
+
memset(&transfer, 0, sizeof(transfer));
command[0] = MCHP23K256_CMD_READ;
mchp23k256_addr2cmd(flash, from, command);

transfer[0].tx_buf = command;
- transfer[0].len = mchp23k256_cmdsz(flash);
+ transfer[0].len = cmd_len;
spi_message_add_tail(&transfer[0], &message);

transfer[1].rx_buf = buf;
@@ -126,8 +130,8 @@ static int mchp23k256_read(struct mtd_in
if (ret)
return ret;

- if (retlen && message.actual_length > sizeof(command))
- *retlen += message.actual_length - sizeof(command);
+ if (retlen && message.actual_length > cmd_len)
+ *retlen += message.actual_length - cmd_len;

return 0;
}