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Subject: Re: [PATCH 1/4] mmc: sdhci-omap: Fix DCRC error handling during
 tuning
To:     Faiz Abbas <faiz_abbas@ti.com>, <linux-kernel@vger.kernel.org>,
        <linux-mmc@vger.kernel.org>
CC:     <ulf.hansson@linaro.org>, <adrian.hunter@intel.com>
References: <20181119111618.2745-1-faiz_abbas@ti.com>
 <20181119111618.2745-2-faiz_abbas@ti.com>
From:   Kishon Vijay Abraham I <kishon@ti.com>
Message-ID: <b4568cfc-55c6-9dfc-6d26-1efc999e95ec@ti.com>
Date:   Tue, 20 Nov 2018 10:23:03 +0530
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Hi,

On 19/11/18 4:46 PM, Faiz Abbas wrote:
> Commit 7d33c3581536 ("mmc: sdhci-omap: Workaround for Errata i802")
> disabled DCRC interrupts during tuning. This write to the interrupt
> enable register gets overwritten in sdhci_prepare_data() and the
> interrupt is not in fact disabled. Fix this by disabling the interrupt
> in the host->ier variable.
> 
> Signed-off-by: Faiz Abbas <faiz_abbas@ti.com>
> ---
>   drivers/mmc/host/sdhci-omap.c | 7 +++----
>   1 file changed, 3 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/mmc/host/sdhci-omap.c b/drivers/mmc/host/sdhci-omap.c
> index 88347ce78f23..87138067e334 100644
> --- a/drivers/mmc/host/sdhci-omap.c
> +++ b/drivers/mmc/host/sdhci-omap.c
> @@ -290,7 +290,6 @@ static int sdhci_omap_execute_tuning(struct mmc_host *mmc, u32 opcode)
>   	u32 start_window = 0, max_window = 0;
>   	u8 cur_match, prev_match = 0;
>   	u32 length = 0, max_len = 0;
> -	u32 ier = host->ier;
>   	u32 phase_delay = 0;
>   	int ret = 0;
>   	u32 reg;
> @@ -317,9 +316,7 @@ static int sdhci_omap_execute_tuning(struct mmc_host *mmc, u32 opcode)
>   	 * during the tuning procedure. So disable it during the
>   	 * tuning procedure.
>   	 */
> -	ier &= ~SDHCI_INT_DATA_CRC;
> -	sdhci_writel(host, ier, SDHCI_INT_ENABLE);
> -	sdhci_writel(host, ier, SDHCI_SIGNAL_ENABLE);
> +	host->ier &= ~SDHCI_INT_DATA_CRC;
>   
>   	while (phase_delay <= MAX_PHASE_DELAY) {
>   		sdhci_omap_set_dll(omap_host, phase_delay);
> @@ -366,6 +363,8 @@ static int sdhci_omap_execute_tuning(struct mmc_host *mmc, u32 opcode)
>   
>   ret:
>   	sdhci_reset(host, SDHCI_RESET_CMD | SDHCI_RESET_DATA);
> +	/* Reenable forbidden interrupt */
> +	host->ier |= SDHCI_INT_DATA_CRC;

It's better to have a backup of host->ier and restore the value here (in 
case DATA_CRC is disabled for other cases).

Thanks
Kishon