pmdomain: bcm: bcm2835-power: check if the ASB register is equal to e…

…nable

commit 2e75396 upstream.

The commit c494a44 ("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: c494a44 ("soc: bcm: bcm2835-power: Refactor ASB control")
Signed-off-by: Maíra Canal <[email protected]>
Reviewed-by: Florian Fainelli <[email protected]>
Reviewed-by: Stefan Wahren <[email protected]>
Cc: [email protected]
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Ulf Hansson <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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;