linux-kernel - Re: [PATCH 2/3] fpga manager: xilinx-spi: provide better diagnostics on programming failure

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Date:   Mon, 17 Aug 2020 11:15:03 -0700
From:   Tom Rix <trix@...hat.com>
To:     Luca Ceresoli <luca@...aceresoli.net>, linux-fpga@...r.kernel.org
Cc:     Moritz Fischer <mdf@...nel.org>,
        Michal Simek <michal.simek@...inx.com>,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        Anatolij Gustschin <agust@...x.de>
Subject: Re: [PATCH 2/3] fpga manager: xilinx-spi: provide better diagnostics
 on programming failure

The other two patches are fine.

On 8/17/20 9:59 AM, Luca Ceresoli wrote:
> When the DONE pin does not go high after programming to confirm programming
> success, the INIT_B pin provides some info on the reason. Use it if
> available to provide a more explanatory error message.
>
> Signed-off-by: Luca Ceresoli <luca@...aceresoli.net>
> ---
>  drivers/fpga/xilinx-spi.c | 11 ++++++++++-
>  1 file changed, 10 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/fpga/xilinx-spi.c b/drivers/fpga/xilinx-spi.c
> index 502fae0d1d85..2aa942bb1114 100644
> --- a/drivers/fpga/xilinx-spi.c
> +++ b/drivers/fpga/xilinx-spi.c
> @@ -169,7 +169,16 @@ static int xilinx_spi_write_complete(struct fpga_manager *mgr,
>  			return xilinx_spi_apply_cclk_cycles(conf);
>  	}
>  
> -	dev_err(&mgr->dev, "Timeout after config data transfer.\n");
> +	if (conf->init_b) {
> +		int init_b_asserted = gpiod_get_value(conf->init_b);

gpiod_get_value can fail. So maybe need split the first statement.

init_b_asserted < 0 ? "invalid device"

As the if-else statement is getting complicated, embedding the ? : makes this hard to read.  'if,else if, else' would be better.

> +
> +		dev_err(&mgr->dev,
> +			init_b_asserted ? "CRC error or invalid device\n"
> +			: "Missing sync word or incomplete bitstream\n");
> +	} else {
> +		dev_err(&mgr->dev, "Timeout after config data transfer.\n");
patch 3 removes '.' s , and you just added one back in ?
> +	}
> +
>  	return -ETIMEDOUT;
>  }
>  

Reviewed-by: Tom Rix <trix@...hat.com>