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References: <20230306225249.975495-1-eajames@linux.ibm.com>
In-Reply-To: <20230306225249.975495-1-eajames@linux.ibm.com>
From:   Joel Stanley <joel@jms.id.au>
Date:   Thu, 9 Mar 2023 05:38:41 +0000
Message-ID: <CACPK8Xda32NL8hvFD0fMTKeQnoBOKCz63W=vMJ+X4p_TJ2LCjw@mail.gmail.com>
Subject: Re: [PATCH] fsi: aspeed: Reset master errors after CFAM reset
To:     Eddie James <eajames@linux.ibm.com>,
        Joachim Fenkes <FENKES@de.ibm.com>
Cc:     linux-fsi@lists.ozlabs.org, linux-kernel@vger.kernel.org,
        andrew@aj.id.au, alistair@popple.id.au, jk@ozlabs.org
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On Mon, 6 Mar 2023 at 22:53, Eddie James <eajames@linux.ibm.com> wrote:
>
> It has been observed that sometimes the FSI master will return all 0xffs
> after a CFAM has been taken out of reset, without presenting any error.
> Resetting the FSI master errors resolves the issue.

Eddie, you mentioned that Joachim was going to provide input on this
change. Did you hear from him?

Cheers,

Joel

>
> Signed-off-by: Eddie James <eajames@linux.ibm.com>
> ---
>  drivers/fsi/fsi-master-aspeed.c | 2 ++
>  1 file changed, 2 insertions(+)
>
> diff --git a/drivers/fsi/fsi-master-aspeed.c b/drivers/fsi/fsi-master-aspeed.c
> index 7cec1772820d..5eccab175e86 100644
> --- a/drivers/fsi/fsi-master-aspeed.c
> +++ b/drivers/fsi/fsi-master-aspeed.c
> @@ -454,6 +454,8 @@ static ssize_t cfam_reset_store(struct device *dev, struct device_attribute *att
>         gpiod_set_value(aspeed->cfam_reset_gpio, 1);
>         usleep_range(900, 1000);
>         gpiod_set_value(aspeed->cfam_reset_gpio, 0);
> +       usleep_range(900, 1000);

Is the delay required? How did you arrive at this time?

> +       opb_writel(aspeed, ctrl_base + FSI_MRESP0, cpu_to_be32(FSI_MRESP_RST_ALL_MASTER));
>         mutex_unlock(&aspeed->lock);
>         trace_fsi_master_aspeed_cfam_reset(false);
>
> --
> 2.31.1
>