Re: [PATCH 4/4] watchdog: aspeed: Move init to arch_initcall

From: Guenter Roeck
Date: Mon Sep 18 2017 - 09:32:55 EST


On 09/17/2017 10:49 PM, Andrew Jeffery wrote:
Probing at device_initcall time lead to perverse cases where the
watchdog was probed after, say, I2C, which then leaves a potentially
running watchdog at the mercy of I2C device behaviour and bus
conditions.

Load the watchdog driver early to ensure that the kernel is patting it
well before initialising peripherals.

But you are doing a bit more. You are making it bool, and you are enabling it
by default. Both isn't needed for the intended goal (arch_initcall is converted
to module_initcall if a driver is built as module). Your change focuses on
and optimizes the case where the watchdog is already running. That may not
always be the case, and there may be systems where the driver is not loaded
on purpose.

Guenter

Signed-off-by: Andrew Jeffery <andrew@xxxxxxxx>
---
drivers/watchdog/Kconfig | 6 ++----
drivers/watchdog/aspeed_wdt.c | 7 ++++++-
2 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index a1b92ebe74b6..6103185983ed 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -741,8 +741,9 @@ config RENESAS_RZAWDT
Renesas RZ/A SoCs. These watchdogs can be used to reset a system.
config ASPEED_WATCHDOG
- tristate "Aspeed BMC watchdog support"
+ bool "Aspeed BMC watchdog support"
depends on ARCH_ASPEED || COMPILE_TEST
+ default y if ARCH_ASPEED
select WATCHDOG_CORE
help
Say Y here to include support for the watchdog timer
@@ -750,9 +751,6 @@ config ASPEED_WATCHDOG
This driver is required to reboot the SoC.
- To compile this driver as a module, choose M here: the
- module will be called aspeed_wdt.
-
config ZX2967_WATCHDOG
tristate "ZTE zx2967 SoCs watchdog support"
depends on ARCH_ZX
diff --git a/drivers/watchdog/aspeed_wdt.c b/drivers/watchdog/aspeed_wdt.c
index 99bc6fbd8852..679c35abadc4 100644
--- a/drivers/watchdog/aspeed_wdt.c
+++ b/drivers/watchdog/aspeed_wdt.c
@@ -313,7 +313,12 @@ static struct platform_driver aspeed_watchdog_driver = {
.of_match_table = of_match_ptr(aspeed_wdt_of_table),
},
};
-module_platform_driver(aspeed_watchdog_driver);
+
+static int __init aspeed_wdt_init(void)
+{
+ return platform_driver_register(&aspeed_watchdog_driver);
+}
+arch_initcall(aspeed_wdt_init);
MODULE_DESCRIPTION("Aspeed Watchdog Driver");
MODULE_LICENSE("GPL");