[v2,16/22] watchdog: ziirave_wdt: Fix JUMP_TO_BOOTLOADER payload
diff mbox series

Message ID 20190812200906.31344-17-andrew.smirnov@gmail.com
State Accepted
Headers show
Series
  • Ziirave_wdt driver fixes
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Commit Message

Andrey Smirnov Aug. 12, 2019, 8:09 p.m. UTC
Bootloader firmware expects the following traffic for
JUMP_TO_BOOTLOADER:

S Addr Wr [A] 0x0c [A] 0x01 [A] P

using ziirave_firm_write_byte() will result in

S Addr Wr [A] 0x0c [A] 0x01 [A] 0x01 [A] P

which happens to work because firmware will ignore any extra bytes and
expected magic value matches byte count sent by
i2c_smbus_write_block_data(). Fix this by converting the code to use
i2c_smbus_write_byte_data() instead.

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Rick Ramstetter <rick@anteaterllc.com>
Cc: linux-watchdog@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
---
 drivers/watchdog/ziirave_wdt.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

Comments

Guenter Roeck Aug. 15, 2019, 6:22 p.m. UTC | #1
On Mon, Aug 12, 2019 at 01:09:00PM -0700, Andrey Smirnov wrote:
> Bootloader firmware expects the following traffic for
> JUMP_TO_BOOTLOADER:
> 
> S Addr Wr [A] 0x0c [A] 0x01 [A] P
> 
> using ziirave_firm_write_byte() will result in
> 
> S Addr Wr [A] 0x0c [A] 0x01 [A] 0x01 [A] P
> 
> which happens to work because firmware will ignore any extra bytes and
> expected magic value matches byte count sent by
> i2c_smbus_write_block_data(). Fix this by converting the code to use
> i2c_smbus_write_byte_data() instead.
> 
> Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
> Cc: Chris Healy <cphealy@gmail.com>
> Cc: Guenter Roeck <linux@roeck-us.net>
> Cc: Rick Ramstetter <rick@anteaterllc.com>
> Cc: linux-watchdog@vger.kernel.org
> Cc: linux-kernel@vger.kernel.org

Reviewed-by: Guenter Roeck <linux@roeck-us.net>

Patch
diff mbox series

diff --git a/drivers/watchdog/ziirave_wdt.c b/drivers/watchdog/ziirave_wdt.c
index 0c150f3cf408..0185b9175cc0 100644
--- a/drivers/watchdog/ziirave_wdt.c
+++ b/drivers/watchdog/ziirave_wdt.c
@@ -72,6 +72,8 @@  static char *ziirave_reasons[] = {"power cycle", "hw watchdog", NULL, NULL,
 #define ZIIRAVE_CMD_JUMP_TO_BOOTLOADER		0x0c
 #define ZIIRAVE_CMD_DOWNLOAD_PACKET		0x0e
 
+#define ZIIRAVE_CMD_JUMP_TO_BOOTLOADER_MAGIC	1
+
 #define ZIIRAVE_FW_VERSION_FMT	"02.%02u.%02u"
 #define ZIIRAVE_BL_VERSION_FMT	"01.%02u.%02u"
 
@@ -376,8 +378,9 @@  static int ziirave_firm_upload(struct watchdog_device *wdd,
 	const struct ihex_binrec *rec;
 	int ret;
 
-	ret = ziirave_firm_write_byte(wdd, ZIIRAVE_CMD_JUMP_TO_BOOTLOADER, 1,
-				      false);
+	ret = i2c_smbus_write_byte_data(client,
+					ZIIRAVE_CMD_JUMP_TO_BOOTLOADER,
+					ZIIRAVE_CMD_JUMP_TO_BOOTLOADER_MAGIC);
 	if (ret) {
 		dev_err(&client->dev, "Failed to jump to bootloader\n");
 		return ret;