linux-kernel - Re: [PATCH] mmc: meson-gx: fix irq ack

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Date:   Tue, 28 May 2019 17:27:16 +1000
From:   Brad Harper <bjharper@...il.com>
To:     Jerome Brunet <jbrunet@...libre.com>,
        Ulf Hansson <ulf.hansson@...aro.org>,
        Kevin Hilman <khilman@...libre.com>
Cc:     linux-amlogic@...ts.infradead.org,
        Neil Armstrong <narmstrong@...libre.com>,
        linux-mmc@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] mmc: meson-gx: fix irq ack

On 24/05/2019 12:59 am, Jerome Brunet wrote:
> While cleaning the ISR of the meson-gx and acking only raised irqs,
> the ack of the irq was moved at the very last stage of the function.
> 
> This was stable during the initial tests but it triggered issues with
> hs200, under specific loads (like booting android). Acking the irqs
> after calling the mmc_request_done() causes the problem.
> 
> Moving the ack back to the original place solves the issue. Since the
> irq is edge triggered, it does not hurt to ack irq even earlier, so
> let's do it early in the ISR.
> 
> Fixes: 9c5fdb07a28d ("mmc: meson-gx: ack only raised irq")
> Tested-by: Neil Armstrong <narmstrong@...libre.com>
> Tested-by: Kevin Hilman <khilman@...libre.com>
> Signed-off-by: Jerome Brunet <jbrunet@...libre.com>
> ---
>   drivers/mmc/host/meson-gx-mmc.c | 6 +++---
>   1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/mmc/host/meson-gx-mmc.c b/drivers/mmc/host/meson-gx-mmc.c
> index 6ef465304052..cb3f6811d69a 100644
> --- a/drivers/mmc/host/meson-gx-mmc.c
> +++ b/drivers/mmc/host/meson-gx-mmc.c
> @@ -873,6 +873,9 @@ static irqreturn_t meson_mmc_irq(int irq, void *dev_id)
>   	if (WARN_ON(!host) || WARN_ON(!host->cmd))
>   		return IRQ_NONE;
>   
> +	/* ack all raised interrupts */
> +	writel(status, host->regs + SD_EMMC_STATUS);
> +
>   	cmd = host->cmd;
>   	data = cmd->data;
>   	cmd->error = 0;
> @@ -919,9 +922,6 @@ static irqreturn_t meson_mmc_irq(int irq, void *dev_id)
>   	if (ret == IRQ_HANDLED)
>   		meson_mmc_request_done(host->mmc, cmd->mrq);
>   
> -	/* ack all raised interrupts */
> -	writel(status, host->regs + SD_EMMC_STATUS);
> -
>   	return ret;
>   }
>   
> 
This patch resolves issues I was having with hung tasks waiting for emmc 
& sd cards on the odroid N2.

Tested-by: Brad Harper <bjharper@...il.com>