[PATCH v2] pmdomain: bcm: bcm2835-power: check if the ASB register is equal to enable

[PATCH v2] pmdomain: bcm: bcm2835-power: check if the ASB register is equal to enable

[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.

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@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..d2f0233cb620 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) {
 		cpu_relax();
 		if (ktime_get_ns() - start >= 1000)
 			return -ETIMEDOUT;
--
2.41.0

Re: [PATCH v2] pmdomain: bcm: bcm2835-power: check if the ASB register is equal to enable

[Florian Fainelli]

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On 10/23/2023 4:35 PM, Maíra Canal wrote:
> 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.
> 
> 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@igalia.com>

Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>

Good catch!
-- 
Florian

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Re: [PATCH v2] pmdomain: bcm: bcm2835-power: check if the ASB register is equal to enable

[Stefan Wahren]

Hi Maíra,

Am 24.10.23 um 01:35 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.
> 
> 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@igalia.com>
> ---

could you please resubmit with a proper changelog (including the 
Reviewed-bys) of this patch?

Reviewed-by: Stefan Wahren <stefan.wahren@i2se.com>

Thanks

>   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..d2f0233cb620 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) {
>   		cpu_relax();
>   		if (ktime_get_ns() - start >= 1000)
>   			return -ETIMEDOUT;
> --
> 2.41.0
>