From 5d6aa89bba5bd6af2580f872b57f438dab883738 Mon Sep 17 00:00:00 2001 From: Darren Hart Date: Thu, 21 Sep 2023 02:02:36 -0700 Subject: [PATCH] sbsa_gwdt: Calculate timeout with 64-bit math Commit abd3ac7902fb ("watchdog: sbsa: Support architecture version 1") introduced new timer math for watchdog revision 1 with the 48 bit offset register. The gwdt->clk and timeout are u32, but the argument being calculated is u64. Without a cast, the compiler performs u32 operations, truncating intermediate steps, resulting in incorrect values. A watchdog revision 1 implementation with a gwdt->clk of 1GHz and a timeout of 600s writes 3647256576 to the one shot watchdog instead of 300000000000, resulting in the watchdog firing in 3.6s instead of 600s. Force u64 math by casting the first argument (gwdt->clk) as a u64. Make the order of operations explicit with parenthesis. Fixes: abd3ac7902fb ("watchdog: sbsa: Support architecture version 1") Reported-by: Vanshidhar Konda Signed-off-by: Darren Hart Cc: Wim Van Sebroeck Cc: Guenter Roeck Cc: linux-watchdog@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: linux-arm-kernel@lists.infradead.org Cc: # 5.14.x Reviewed-by: Guenter Roeck Link: https://lore.kernel.org/r/7d1713c5ffab19b0f3de796d82df19e8b1f340de.1695286124.git.darren@os.amperecomputing.com Signed-off-by: Guenter Roeck Signed-off-by: Wim Van Sebroeck --- drivers/watchdog/sbsa_gwdt.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/watchdog/sbsa_gwdt.c b/drivers/watchdog/sbsa_gwdt.c index 421ebcda62e6..5f23913ce3b4 100644 --- a/drivers/watchdog/sbsa_gwdt.c +++ b/drivers/watchdog/sbsa_gwdt.c @@ -152,14 +152,14 @@ static int sbsa_gwdt_set_timeout(struct watchdog_device *wdd, timeout = clamp_t(unsigned int, timeout, 1, wdd->max_hw_heartbeat_ms / 1000); if (action) - sbsa_gwdt_reg_write(gwdt->clk * timeout, gwdt); + sbsa_gwdt_reg_write((u64)gwdt->clk * timeout, gwdt); else /* * In the single stage mode, The first signal (WS0) is ignored, * the timeout is (WOR * 2), so the WOR should be configured * to half value of timeout. */ - sbsa_gwdt_reg_write(gwdt->clk / 2 * timeout, gwdt); + sbsa_gwdt_reg_write(((u64)gwdt->clk / 2) * timeout, gwdt); return 0; }