[Letux-kernel] omap_hsmmc + gta04 + sdio irq + runtime_suspend + 4 bit = trouble

[Andreas Kemnade]

On Tue, 4 Sep 2018 21:41:17 +0200
Andreas Kemnade <andreas at kemnade.info> wrote:

> Hi,
> 
[...]                                                                                                                                                                                                                                                                           
> 
> [...]
>      &mmc2 {
>         pinctrl-names = "default", "idle";
>         pinctrl-0 = <&mmc2_pins>;
>         pinctrl-1 = <&mmc2_idle_pins>;
> 
>         /* dat1 remuxed as gpio133 */
>         interrupts-extended = <&intc 86>, <&gpio5 5 IRQ_TYPE_LEVEL_LOW>;
>         vmmc-supply = <&vaux4>;
>         bus-width = <4>;
>         ti,non-removable;       /* remove ti, */
>         mmc-pwrseq = <&wifi_pwrseq>;
>         cap-power-off-card;     /* remove! */
> };
>                                                                                                                                                                                                                                                                
> 
> Result: works with 4bit, Irq count is sane as long as the card
> is powered on. On a wifi with low traffic I get around 2 irqs per second
> But if as soon as I power off the card by doing ifconfig down, I get
> around 10 irqs per second which could be explained by the fact that
> autosuspend time is 100ms, and it is waking up just immediately.
> Reason is probably that the other side of the level shifter powered
> off and low, so
> dat1 will be low permanently. And since wakeup is enabled regardless of
> whether sdio irq or anything else is enabled, hsmmc will never get a
> good sleep.
> That behavior (I have to check that) was probably introduced by
> 5b83b2234be6 ("mmc: omap_hsmmc: Change wake-up interrupt to use generic wakeirq").
> 
> I guess there is also a race somehow involved here.
Ok, what fixes the problem:
use above mentioned devicetree, reverting 5b83b2234be6 and
applying this patch:
--- a/drivers/mmc/host/omap_hsmmc.c
+++ b/drivers/mmc/host/omap_hsmmc.c
@@ -2276,6 +2276,14 @@ static int omap_hsmmc_runtime_suspend(struct device *dev)
        int ret = 0;
 
        host = platform_get_drvdata(to_platform_device(dev));
+       spin_lock_irqsave(&host->irq_lock, flags);
+       if ((host->mmc->caps & MMC_CAP_SDIO_IRQ) &&
+           (host->flags & HSMMC_SDIO_IRQ_ENABLED)) {
+               WARN_ON(host->flags & HSMMC_WAKE_IRQ_ENABLED);
+               enable_irq(host->wake_irq);
+               host->flags |= HSMMC_WAKE_IRQ_ENABLED;
+       }
+       spin_unlock_irqrestore(&host->irq_lock, flags);
        omap_hsmmc_context_save(host);
        dev_dbg(dev, "disabled\n");
 
@@ -2303,9 +2311,6 @@ static int omap_hsmmc_runtime_suspend(struct device *dev)
 
                pinctrl_pm_select_idle_state(dev);
 
-               WARN_ON(host->flags & HSMMC_WAKE_IRQ_ENABLED);
-               enable_irq(host->wake_irq);
-               host->flags |= HSMMC_WAKE_IRQ_ENABLED;
        } else {
                pinctrl_pm_select_idle_state(dev);
        }

This brings things in the same order as done with generic wakeirq. So I
just have to convert this into a clean patch using the generic wakeirq
api and add the devicetree entry.

Regards,
Andreas
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