Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
From:   =?iso-8859-1?Q?Christian_L=F6hle?= <CLoehle@hyperstone.com>
To:     Jaehoon Chung <jh80.chung@samsung.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "linux-mmc@vger.kernel.org" <linux-mmc@vger.kernel.org>
CC:     "marten.lindahl@axis.com" <marten.lindahl@axis.com>,
        "ulf.hansson@linaro.org" <ulf.hansson@linaro.org>
Subject: Re: [PATCH] mmc: dw_mmc: avoid long timeout if register invalid
Thread-Topic: [PATCH] mmc: dw_mmc: avoid long timeout if register invalid
Thread-Index: AQHXq5f2H1xcZooo4kGJdi3JsFt1D6uy2hoAgAfLcc8=
Date:   Wed, 29 Sep 2021 06:53:56 +0000
Message-ID: <cfe4476922584dff91bf0fdbec0c0843@hyperstone.com>
References: <CGME20210917075050epcas1p1962cd1c7c388b20ad17cb841461dae1b@epcas1p1.samsung.com>
        <bf19053cf6f547bcbb364975cda84c30@hyperstone.com>,<a8031e66-77a0-ae9b-d78d-daebc1d7dc47@samsung.com>
In-Reply-To: <a8031e66-77a0-ae9b-d78d-daebc1d7dc47@samsung.com>
Accept-Language: en-US, de-DE
Content-Language: en-US
Content-Type: text/plain;
        charset="iso-8859-1"
Content-Transfer-Encoding: 8BIT
MIME-Version: 1.0
Precedence: bulk

Hey,
so more generally the timeout here can be 41954 up to 167783 ms.
Is 42s too low to view it as invalid here?
Would you prefer the patch exluding the specific timeout values instead of anything above
41954?

Regards,
Christian


From: Jaehoon Chung <jh80.chung@samsung.com>
Sent: Friday, September 24, 2021 11:49 AM
To: Christian L?hle; linux-kernel@vger.kernel.org; linux-mmc@vger.kernel.org
Cc: marten.lindahl@axis.com; ulf.hansson@linaro.org
Subject: Re: [PATCH] mmc: dw_mmc: avoid long timeout if register invalid
?   
Hi,

On 9/17/21 4:50 PM, Christian L?hle wrote:
> 
> Set the limit to 1s if the register is at reset value.
> 
> Signed-off-by: Christian Loehle <cloehle@hyperstone.com>
> ---
>? drivers/mmc/host/dw_mmc.c | 8 ++++++++
>? 1 file changed, 8 insertions(+)
> 
> diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
> index 6578cc64ae9e..cd9a6e0a7449 100644
> --- a/drivers/mmc/host/dw_mmc.c
> +++ b/drivers/mmc/host/dw_mmc.c
> @@ -1983,6 +1983,14 @@ static void dw_mci_set_drto(struct dw_mci *host)
>??????? /* add a bit spare time */
>??????? drto_ms += 10;
>? 
> +???? /*
> +????? * If TMOUT register still holds the reset value the above calculation
> +????? * would yield a timeout of over 167 seconds, limit it to 1000ms.
> +????? * Normal reads/writes should not take anywhere close to 120s.
> +????? */
> +???? if (drto_ms > 120000)
> +???????????? drto_ms = 1000;
> +

If dtrt_ms is 167sec, it means that bus_hz should be 0 or 1.
What value is your host->bus_hz?

Best Regards,
Jaehoon Chung

>??????? spin_lock_irqsave(&host->irq_lock, irqflags);
>??????? if (!test_bit(EVENT_DATA_COMPLETE, &host->pending_events))
>??????????????? mod_timer(&host->dto_timer,
> 

    =
Hyperstone GmbH | Line-Eid-Strasse 3 | 78467 Konstanz
Managing Directors: Dr. Jan Peter Berns.
Commercial register of local courts: Freiburg HRB381782