netdev - Re: [PATCH v2 net-next 03/11] sfc_ef100: read Design Parameters at probe time

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Message-ID: <20200731131857.41b0f32a@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com>
Date:   Fri, 31 Jul 2020 13:18:57 -0700
From:   Jakub Kicinski <kuba@...nel.org>
To:     Edward Cree <ecree@...arflare.com>
Cc:     <linux-net-drivers@...arflare.com>, <davem@...emloft.net>,
        <netdev@...r.kernel.org>
Subject: Re: [PATCH v2 net-next 03/11] sfc_ef100: read Design Parameters at
 probe time

On Fri, 31 Jul 2020 13:58:35 +0100 Edward Cree wrote:
> +	default:
> +		/* Host interface says "Drivers should ignore design parameters
> +		 * that they do not recognise."
> +		 */
> +		netif_info(efx, probe, efx->net_dev,
> +			   "Ignoring unrecognised design parameter %u\n",
> +			   reader->type);

Is this really important enough to spam the logs with?

> +		return 0;
> +	}
> +}
> +
> +static int ef100_check_design_params(struct efx_nic *efx)
> +{
> +	struct ef100_tlv_state reader = {};
> +	u32 total_len, offset = 0;
> +	efx_dword_t reg;
> +	int rc = 0, i;
> +	u32 data;
> +
> +	efx_readd(efx, &reg, ER_GZ_PARAMS_TLV_LEN);
> +	total_len = EFX_DWORD_FIELD(reg, EFX_DWORD_0);
> +	netif_dbg(efx, probe, efx->net_dev, "%u bytes of design parameters\n",
> +		  total_len);
> +	while (offset < total_len) {
> +		efx_readd(efx, &reg, ER_GZ_PARAMS_TLV + offset);
> +		data = EFX_DWORD_FIELD(reg, EFX_DWORD_0);
> +		for (i = 0; i < sizeof(data); i++) {
> +			rc = ef100_tlv_feed(&reader, data);
> +			/* Got a complete value? */
> +			if (!rc && reader.state == EF100_TLV_TYPE)
> +				rc = ef100_process_design_param(efx, &reader);
> +			if (rc)
> +				goto out;
> +			data >>= 8;
> +			offset++;
> +		}
> +	}

Should you warn if the TLV stream ends half-way through an entry?

> +out:
> +	return rc;
> +}