Re: [RFC PATCH 2/2] net: ethtool: Add capability to retrieve plug-in module EEPROM

Ben Hutchings
2012-04-02T18:18:23Z

On Tue, 2012-03-27 at 18:51 +0100, Stuart Hodgson wrote:
> Implementation in sfc driver to return the plugin module eeprom
>
> Currently allows for SFP+ eeprom to be returned using the ethtool API.
> This can be extended in future to handle different eeprom formats
> and sizes.
>
> Signed-off-by: Stuart Hodgson <smhodgson@solarflare.com>
> ---
> drivers/net/ethernet/sfc/ethtool.c | 36 +++++++++++
> drivers/net/ethernet/sfc/mcdi_phy.c | 105
> +++++++++++++++++++++++++++++++++
> drivers/net/ethernet/sfc/net_driver.h | 5 ++
> 3 files changed, 146 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/net/ethernet/sfc/ethtool.c
> b/drivers/net/ethernet/sfc/ethtool.c
> index f22f45f..e77895f 100644
> --- a/drivers/net/ethernet/sfc/ethtool.c
> +++ b/drivers/net/ethernet/sfc/ethtool.c
> @@ -1108,6 +1108,40 @@ static int efx_ethtool_set_rxfh_indir(struct
> net_device *net_dev,
> return 0;
> }
>
> +static int efx_ethtool_get_module_eeprom(struct net_device *net_dev,
> + struct ethtool_eeprom *ee,
> + u8 *data)
> +{
> + struct efx_nic *efx = netdev_priv(net_dev);
> + int ret;
> +
> + if (!efx->phy_op ||
> + !efx->phy_op->get_module_eeprom)

No need to break that line.

[...]
> --- a/drivers/net/ethernet/sfc/mcdi_phy.c
> +++ b/drivers/net/ethernet/sfc/mcdi_phy.c
> @@ -304,6 +304,17 @@ static u32 mcdi_to_ethtool_media(u32 media)
> }
> }
>
> +static u32 mcdi_to_module_eeprom_len(u32 media)
> +{
> + switch (media) {
> + case MC_CMD_MEDIA_SFP_PLUS:
> + return SFF_8079_LEN;
> + case MC_CMD_MEDIA_XFP:

Why split out XFP if we're not going to treat it any differently?

> + default:
> + return 0;
> + }
> +}
> +
> static int efx_mcdi_phy_probe(struct efx_nic *efx)
> {
> struct efx_mcdi_phy_data *phy_data;
> @@ -739,6 +750,98 @@ static const char *efx_mcdi_phy_test_name(struct
> efx_nic *efx,
> return NULL;
> }
>
> +#define SFP_PAGE_SIZE 128
> +#define NUM_PAGES 2

SFP_NUM_PAGES?

> +#define OFF_TO_BUFF(x) (x + MC_CMD_GET_PHY_MEDIA_INFO_OUT_DATA_OFST)

This is not really worth defining for just the one use.

> +static int efx_mcdi_phy_get_module_eeprom(struct efx_nic *efx,
> + struct ethtool_eeprom *ee, u8 *data)
> +{
> + u8 outbuf[MC_CMD_GET_PHY_MEDIA_INFO_OUT_LENMAX];
> + u8 inbuf[MC_CMD_GET_PHY_MEDIA_INFO_IN_LEN];
> + size_t outlen;
> + int rc;
> + int payload_len;
> + int copied = 0;
> + int space_remaining = ee->len;
> + int page;
> + int page_off;
> + int to_copy;

None of payload_len..to_copy should be signed.

> + u8 *user_data = data;
> +
> + if (!data || !ee)
> + return -EINVAL;

Neither of these is allowed to be NULL; don't bother checking.

> + if (ee->offset > (SFP_PAGE_SIZE * NUM_PAGES)) {
> + rc = -EINVAL;
> + goto fail;
> + }
> +
> + page_off = (ee->offset % SFP_PAGE_SIZE);
> + page = (ee->offset > SFP_PAGE_SIZE) ? 1 : 0;

Why not ee->offset / SFP_PAGE_SIZE?

> + while (space_remaining && (page < NUM_PAGES)) {
> +
> + MCDI_SET_DWORD(inbuf, GET_PHY_MEDIA_INFO_IN_PAGE, page);
> +
> + rc = efx_mcdi_rpc(efx, MC_CMD_GET_PHY_MEDIA_INFO,
> + inbuf, sizeof(inbuf),
> + outbuf, sizeof(outbuf),
> + &outlen);
> +
> + if (rc)
> + goto fail;
> +
> + /* Copy as much as we can into data */
> + if (outlen < MC_CMD_GET_PHY_MEDIA_INFO_OUT_LENMIN ||
> + outlen > MC_CMD_GET_PHY_MEDIA_INFO_OUT_LENMAX) {
> + rc = -EIO;
> + goto fail;
> + }
> +
> + payload_len = MCDI_DWORD(outbuf,
> + GET_PHY_MEDIA_INFO_OUT_DATALEN);
> +
> + to_copy = (space_remaining < payload_len) ?
> + space_remaining : payload_len;
> +
> + to_copy -= page_off;

page_off is the number of bytes we need to discard from payload_len, but
we don't want do discard that from space_remaining. I think the last
two statements should be changed to:

payload_len -= page_off;
to_copy = (space_remaining < payload_len) ?
space_remaining : payload_len;

> + memcpy(user_data,
> + (outbuf + OFF_TO_BUFF(page_off)),
> + to_copy);
> +
> + space_remaining -= to_copy;
> + user_data += to_copy;
> + copied += to_copy;
> + page_off = 0;
> + page++;
> + }
> +
> + ee->len = copied;
> +
> + return 0;
> +fail:
> + return rc;

Nothing to clean up here, so you might as well return errors directly.

> +}
> +
> +static int efx_mcdi_phy_get_module_info(struct efx_nic *efx,
> + struct ethtool_modinfo *modinfo)
> +{
> + /* This will return a length of the eeprom
> + * type of the module that was detected during the probe,
> + * if not modules inserted then phy_data will be NULL */
> + struct efx_mcdi_phy_data *phy_cfg;
> +
> + if (!efx || !efx->phy_data)
> + return -EOPNOTSUPP;

efx certainly can't be NULL here and I don't believe efx->phy_data can
either. (None of the other MCDI PHY operations check it.)

> + phy_cfg = efx->phy_data;
> + modinfo->eeprom_len = mcdi_to_module_eeprom_len(phy_cfg->media);
> + modinfo->type = SFF_8079;
[...]

I don't think this makes sense. If we're fixing the type as SFF_8079
then why are we calling a function to get the length?

Ben.

--
Ben Hutchings, Staff Engineer, Solarflare
Not speaking for my employer; that's the marketing department's job.
They asked us to note that Solarflare product names are trademarked.