linux-kernel - Re: [PATCH] fpga: altera-cvp: allow interrupt to continue next time

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Message-ID: <b0fd6c41-f8a4-bb3a-d05a-2ea17d4ffc80@redhat.com>
Date:   Wed, 18 May 2022 07:04:34 -0700
From:   Tom Rix <trix@...hat.com>
To:     tien.sung.ang@...el.com, mdf@...nel.org, hao.wu@...el.com,
        yilun.xu@...el.com
Cc:     linux-fpga@...r.kernel.org, linux-kernel@...r.kernel.org,
        Dinh Nguyen <dinh.nguyen@...el.com>
Subject: Re: [PATCH] fpga: altera-cvp: allow interrupt to continue next time


On 5/18/22 12:38 AM, tien.sung.ang@...el.com wrote:
> From: Dinh Nguyen <dinh.nguyen@...el.com>
>
> CFG_READY signal/bit may time-out due to firmware not responding
> within the given time-out. This time varies due to numerous
> factors like size of bitstream and others.
> This time-out error does not impact the result of the CvP
> previous transactions. The CvP driver shall then, respond with
> EAGAIN instead Time out error.
>
> Signed-off-by: Dinh Nguyen <dinh.nguyen@...el.com>
> Signed-off-by: Ang Tien Sung <tien.sung.ang@...el.com>
> ---
>   drivers/fpga/altera-cvp.c | 14 +++++++++++++-
>   1 file changed, 13 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/fpga/altera-cvp.c b/drivers/fpga/altera-cvp.c
> index 4ffb9da537d8..d74ff63c61e8 100644
> --- a/drivers/fpga/altera-cvp.c
> +++ b/drivers/fpga/altera-cvp.c
> @@ -309,10 +309,22 @@ static int altera_cvp_teardown(struct fpga_manager *mgr,
>   	/* STEP 15 - poll CVP_CONFIG_READY bit for 0 with 10us timeout */
>   	ret = altera_cvp_wait_status(conf, VSE_CVP_STATUS_CFG_RDY, 0,
>   				     conf->priv->poll_time_us);
> -	if (ret)
> +	if (ret) {
>   		dev_err(&mgr->dev, "CFG_RDY == 0 timeout\n");
> +		goto error_path;
> +	}
>   
>   	return ret;
> +
> +error_path:
> +	/* reset CVP_MODE and HIP_CLK_SEL bit */
> +	altera_read_config_dword(conf, VSE_CVP_MODE_CTRL, &val);
> +	val &= ~VSE_CVP_MODE_CTRL_HIP_CLK_SEL;
> +	val &= ~VSE_CVP_MODE_CTRL_CVP_MODE;
> +	altera_write_config_dword(conf, VSE_CVP_MODE_CTRL, val);
> +
> +	return -EAGAIN;

This will set fpga_mgr->state to *_ERR.

Is this ok or do you think we need a couple new of *_BUSY enums ?

Tom

> +
>   }
>   
>   static int altera_cvp_write_init(struct fpga_manager *mgr,