Re: [PATCH] watchdog: bcm7038_wdt: add big endian support

From: Guenter Roeck
Date: Mon Feb 22 2021 - 16:24:52 EST


On 2/22/21 12:03 PM, Álvaro Fernández Rojas wrote:
> bcm7038_wdt can be used on bmips (bcm63xx) devices too.
>
It might make sense to actually enable it for BCM63XX.

> Signed-off-by: Álvaro Fernández Rojas <noltari@xxxxxxxxx>
> ---
> drivers/watchdog/bcm7038_wdt.c | 30 ++++++++++++++++++++++++------
> 1 file changed, 24 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/watchdog/bcm7038_wdt.c b/drivers/watchdog/bcm7038_wdt.c
> index 979caa18d3c8..62494da1ac57 100644
> --- a/drivers/watchdog/bcm7038_wdt.c
> +++ b/drivers/watchdog/bcm7038_wdt.c
> @@ -34,6 +34,24 @@ struct bcm7038_watchdog {
>
> static bool nowayout = WATCHDOG_NOWAYOUT;
>
> +static inline void bcm7038_wdt_write(unsigned long data, void __iomem *reg)
> +{
> +#ifdef CONFIG_CPU_BIG_ENDIAN
> + __raw_writel(data, reg);
> +#else
> + writel(data, reg);
> +#endif
> +}
> +
> +static inline unsigned long bcm7038_wdt_read(void __iomem *reg)
> +{
> +#ifdef CONFIG_CPU_BIG_ENDIAN
> + return __raw_readl(reg);
> +#else
> + return readl(reg);
> +#endif
> +}
> +

This needs further explanation. Why not just use __raw_writel() and
__raw_readl() unconditionally ? Also, is it known for sure that,
say, bmips_be_defconfig otherwise uses the wrong endianness
(vs. bmips_stb_defconfig which is a little endian configuration) ?

Thanks,
Guenter

> static void bcm7038_wdt_set_timeout_reg(struct watchdog_device *wdog)
> {
> struct bcm7038_watchdog *wdt = watchdog_get_drvdata(wdog);
> @@ -41,15 +59,15 @@ static void bcm7038_wdt_set_timeout_reg(struct watchdog_device *wdog)
>
> timeout = wdt->rate * wdog->timeout;
>
> - writel(timeout, wdt->base + WDT_TIMEOUT_REG);
> + bcm7038_wdt_write(timeout, wdt->base + WDT_TIMEOUT_REG);
> }
>
> static int bcm7038_wdt_ping(struct watchdog_device *wdog)
> {
> struct bcm7038_watchdog *wdt = watchdog_get_drvdata(wdog);
>
> - writel(WDT_START_1, wdt->base + WDT_CMD_REG);
> - writel(WDT_START_2, wdt->base + WDT_CMD_REG);
> + bcm7038_wdt_write(WDT_START_1, wdt->base + WDT_CMD_REG);
> + bcm7038_wdt_write(WDT_START_2, wdt->base + WDT_CMD_REG);
>
> return 0;
> }
> @@ -66,8 +84,8 @@ static int bcm7038_wdt_stop(struct watchdog_device *wdog)
> {
> struct bcm7038_watchdog *wdt = watchdog_get_drvdata(wdog);
>
> - writel(WDT_STOP_1, wdt->base + WDT_CMD_REG);
> - writel(WDT_STOP_2, wdt->base + WDT_CMD_REG);
> + bcm7038_wdt_write(WDT_STOP_1, wdt->base + WDT_CMD_REG);
> + bcm7038_wdt_write(WDT_STOP_2, wdt->base + WDT_CMD_REG);
>
> return 0;
> }
> @@ -88,7 +106,7 @@ static unsigned int bcm7038_wdt_get_timeleft(struct watchdog_device *wdog)
> struct bcm7038_watchdog *wdt = watchdog_get_drvdata(wdog);
> u32 time_left;
>
> - time_left = readl(wdt->base + WDT_CMD_REG);
> + time_left = bcm7038_wdt_read(wdt->base + WDT_CMD_REG);
>
> return time_left / wdt->rate;
> }
>