Re: [PATCH] fpga: socfpga-a10: Propagate DCLK completion timeouts

[Xu Yilun]

On Sun, Sep 06, 2026 at 11:39:00AM +0800, Pengpeng Hou wrote:
> socfpga_a10_fpga_generate_dclks() waits for the generated DCLK count to
> complete but discards the poll result. Configuration can therefore continue
> after the hardware did not acknowledge a required DCLK sequence.

The process can fail on multiple operations, breaking out only on
xx_generate_dclks() doesn't make much sense. I think if the final checks
can be the last safety net, then it is fine.

Do you find any real issue at runtime?

> 
> Return the poll result and stop write initialization on failure. During
> write completion, retain the existing cleanup sequence and return the
> earlier PR error in preference to a later DCLK error.
> 
> The issue was found by our static-analysis tool and manually reviewed.
> 
> Fixes: acbb910ae04b ("fpga-manager: Add Socfpga Arria10 support")
> Assisted-by: gpt 5
> Signed-off-by: Pengpeng Hou <hppiscas@xxxxxxx>
> ---
>  drivers/fpga/socfpga-a10.c | 26 ++++++++++++++++++--------
>  1 file changed, 18 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/fpga/socfpga-a10.c b/drivers/fpga/socfpga-a10.c
> index 0165a3c86932..f707c2bdc189 100644
> --- a/drivers/fpga/socfpga-a10.c
> +++ b/drivers/fpga/socfpga-a10.c
> @@ -124,10 +124,11 @@ static void socfpga_a10_fpga_set_cfg_width(struct a10_fpga_priv *priv,
>  			   A10_FPGAMGR_IMGCFG_CTL_02_CFGWIDTH, width);
>  }
>  
> -static void socfpga_a10_fpga_generate_dclks(struct a10_fpga_priv *priv,
> -					    u32 count)
> +static int socfpga_a10_fpga_generate_dclks(struct a10_fpga_priv *priv,
> +					   u32 count)
>  {
>  	u32 val;
> +	int ret;
>  
>  	/* Clear any existing DONE status. */
>  	regmap_write(priv->regmap, A10_FPGAMGR_DCLKSTAT_OFST,
> @@ -137,12 +138,15 @@ static void socfpga_a10_fpga_generate_dclks(struct a10_fpga_priv *priv,
>  	regmap_write(priv->regmap, A10_FPGAMGR_DCLKCNT_OFST, count);
>  
>  	/* wait till the dclkcnt done */
> -	regmap_read_poll_timeout(priv->regmap, A10_FPGAMGR_DCLKSTAT_OFST, val,
> -				 val, 1, 100);
> +	ret = regmap_read_poll_timeout(priv->regmap,
> +				       A10_FPGAMGR_DCLKSTAT_OFST, val,
> +				       val, 1, 100);
>  
>  	/* Clear DONE status. */
>  	regmap_write(priv->regmap, A10_FPGAMGR_DCLKSTAT_OFST,
>  		     A10_FPGAMGR_DCLKSTAT_DCLKDONE);
> +
> +	return ret;
>  }
>  
>  #define RBF_ENCRYPTION_MODE_OFFSET		69
> @@ -334,7 +338,9 @@ static int socfpga_a10_fpga_write_init(struct fpga_manager *mgr,
>  			   A10_FPGAMGR_IMGCFG_CTL_01_S2F_NENABLE_CONFIG, 0);
>  
>  	/* Send some clocks to clear out any errors */
> -	socfpga_a10_fpga_generate_dclks(priv, 256);
> +	ret = socfpga_a10_fpga_generate_dclks(priv, 256);
> +	if (ret)
> +		return ret;
>  
>  	/* Assert pr_request */
>  	regmap_update_bits(priv->regmap, A10_FPGAMGR_IMGCFG_CTL_01_OFST,
> @@ -342,7 +348,9 @@ static int socfpga_a10_fpga_write_init(struct fpga_manager *mgr,
>  			   A10_FPGAMGR_IMGCFG_CTL_01_S2F_PR_REQUEST);
>  
>  	/* Provide 2048 DCLKs before starting the config data streaming. */
> -	socfpga_a10_fpga_generate_dclks(priv, 0x7ff);
> +	ret = socfpga_a10_fpga_generate_dclks(priv, 0x7ff);
> +	if (ret)
> +		return ret;
>  
>  	/* Wait for pr_ready */
>  	return socfpga_a10_fpga_wait_for_pr_ready(priv);
> @@ -393,7 +401,7 @@ static int socfpga_a10_fpga_write_complete(struct fpga_manager *mgr,
>  {
>  	struct a10_fpga_priv *priv = mgr->priv;
>  	u32 reg;
> -	int ret;
> +	int dclk_ret, ret;
>  
>  	/* Wait for pr_done */
>  	ret = socfpga_a10_fpga_wait_for_pr_done(priv);
> @@ -403,7 +411,7 @@ static int socfpga_a10_fpga_write_complete(struct fpga_manager *mgr,
>  			   A10_FPGAMGR_IMGCFG_CTL_01_S2F_PR_REQUEST, 0);
>  
>  	/* Send some clocks to clear out any errors */
> -	socfpga_a10_fpga_generate_dclks(priv, 256);
> +	dclk_ret = socfpga_a10_fpga_generate_dclks(priv, 256);
>  
>  	/* Disable s2f dclk and data */
>  	regmap_update_bits(priv->regmap, A10_FPGAMGR_IMGCFG_CTL_02_OFST,
> @@ -422,6 +430,8 @@ static int socfpga_a10_fpga_write_complete(struct fpga_manager *mgr,
>  	/* Return any errors regarding pr_done or pr_error */
>  	if (ret)
>  		return ret;
> +	if (dclk_ret)
> +		return dclk_ret;
>  
>  	/* Final check */
>  	reg = socfpga_a10_fpga_read_stat(priv);
> -- 
> 2.50.1 (Apple Git-155)
> 
>