netdev - Re: [PATCH net-next] net: phy: sfp: Cotsworks SFF module EEPROM fixup

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Date:   Wed, 15 Jul 2020 20:10:54 -0700
From:   Florian Fainelli <f.fainelli@...il.com>
To:     Chris Healy <cphealy@...il.com>, linux@...linux.org.uk,
        andrew@...n.ch, hkallweit1@...il.com, davem@...emloft.net,
        kuba@...nel.org, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH net-next] net: phy: sfp: Cotsworks SFF module EEPROM fixup



On 7/14/2020 10:59 AM, Chris Healy wrote:
> Some Cotsworks SFF have invalid data in the first few bytes of the
> module EEPROM.  This results in these modules not being detected as
> valid modules.
> 
> Address this by poking the correct EEPROM values into the module
> EEPROM when the model/PN match and the existing module EEPROM contents
> are not correct.
> 
> Signed-off-by: Chris Healy <cphealy@...il.com>
> ---
>  drivers/net/phy/sfp.c | 44 +++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 44 insertions(+)
> 
> diff --git a/drivers/net/phy/sfp.c b/drivers/net/phy/sfp.c
> index 73c2969f11a4..2737d9b6b0ae 100644
> --- a/drivers/net/phy/sfp.c
> +++ b/drivers/net/phy/sfp.c
> @@ -1632,10 +1632,43 @@ static int sfp_sm_mod_hpower(struct sfp *sfp, bool enable)
>  	return 0;
>  }
>  
> +static int sfp_cotsworks_fixup_check(struct sfp *sfp, struct sfp_eeprom_id *id)
> +{
> +	u8 check;
> +	int err;
> +
> +	if (id->base.phys_id != SFF8024_ID_SFF_8472 ||
> +	    id->base.phys_ext_id != SFP_PHYS_EXT_ID_SFP ||
> +	    id->base.connector != SFF8024_CONNECTOR_LC) {
> +		dev_warn(sfp->dev, "Rewriting fiber module EEPROM with corrected values\n");
> +		id->base.phys_id = SFF8024_ID_SFF_8472;
> +		id->base.phys_ext_id = SFP_PHYS_EXT_ID_SFP;
> +		id->base.connector = SFF8024_CONNECTOR_LC;
> +		err = sfp_write(sfp, false, SFP_PHYS_ID, &id->base, 3);
> +		if (err != 3) {
> +			dev_err(sfp->dev, "Failed to rewrite module EEPROM: %d\n", err);
> +			return err;
> +		}
> +
> +		/* Cotsworks modules have been found to require a delay between write operations. */
> +		mdelay(50);
> +
> +		/* Update base structure checksum */
> +		check = sfp_check(&id->base, sizeof(id->base) - 1);
> +		err = sfp_write(sfp, false, SFP_CC_BASE, &check, 1);
> +		if (err != 1) {
> +			dev_err(sfp->dev, "Failed to update base structure checksum in fiber module EEPROM: %d\n", err);
> +			return err;
> +		}
> +	}
> +	return 0;
> +}
> +
>  static int sfp_sm_mod_probe(struct sfp *sfp, bool report)
>  {
>  	/* SFP module inserted - read I2C data */
>  	struct sfp_eeprom_id id;
> +	bool cotsworks_sfbg;
>  	bool cotsworks;
>  	u8 check;
>  	int ret;
> @@ -1657,6 +1690,17 @@ static int sfp_sm_mod_probe(struct sfp *sfp, bool report)
>  	 * serial number and date code.
>  	 */
>  	cotsworks = !memcmp(id.base.vendor_name, "COTSWORKS       ", 16);
> +	cotsworks_sfbg = !memcmp(id.base.vendor_pn, "SFBG", 4);
> +
> +	/* Cotsworks SFF module EEPROM do not always have valid phys_id,
> +	 * phys_ext_id, and connector bytes.  Rewrite SFF EEPROM bytes if
> +	 * Cotsworks PN matches and bytes are not correct.
> +	 */
> +	if (cotsworks && cotsworks_sfbg) {
> +		ret = sfp_cotsworks_fixup_check(sfp, &id);
> +		if (ret < 0)
> +			return ret;
> +	}

So with the fixup you introduce, should we ever go into a situation where:

EPROM extended structure checksum failure

is printed?
-- 
Florian