[PATCH] pmdomain: bcm: bcm2835-power: check if the ASB register is equal to enable

[Stefan Wahren]

Hi Maíra,

Am 23.10.23 um 16:49 schrieb Maíra Canal:
> The commit c494a447c14e ("soc: bcm: bcm2835-power: Refactor ASB control")
> refactored the ASB control by using a general function to handle both
> the enable and disable. But this patch introduced a subtle regression:
> we need to check if (readl(base + reg) & ASB_ACK) == enable, not just
> check if (readl(base + reg) & ASB_ACK) == true.

thanks for finding this regression

> 
> Currently, this is causing an invalid register state in V3D when
> unloading and loading the driver, because `bcm2835_asb_disable()` will
> return -ETIMEDOUT and `bcm2835_asb_power_off()` will fail to disable the
> ASB slave for V3D.
> 
> Fixes: c494a447c14e ("soc: bcm: bcm2835-power: Refactor ASB control")
> Signed-off-by: Maíra Canal <mcanal at igalia.com>
> ---
>   drivers/pmdomain/bcm/bcm2835-power.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/pmdomain/bcm/bcm2835-power.c b/drivers/pmdomain/bcm/bcm2835-power.c
> index 1a179d4e011c..2d3636bc277e 100644
> --- a/drivers/pmdomain/bcm/bcm2835-power.c
> +++ b/drivers/pmdomain/bcm/bcm2835-power.c
> @@ -175,7 +175,7 @@ static int bcm2835_asb_control(struct bcm2835_power *power, u32 reg, bool enable
>   	}
>   	writel(PM_PASSWORD | val, base + reg);
> 
> -	while (readl(base + reg) & ASB_ACK) {
> +	while ((readl(base + reg) & ASB_ACK) == enable) {

but shouldn't it be:

while (!!(readl(base + reg) & ASB_ACK) == enable) ?

>   		cpu_relax();
>   		if (ktime_get_ns() - start >= 1000)
>   			return -ETIMEDOUT;
> --
> 2.41.0
>