sfc: handle limited FEC support

If the reported PHY capabilities do not include a given FEC mode, don't
 attempt to select that FEC mode anyway.  If the user tries to set a mode
 through ethtool that is not supported, return an error.
The _REQUESTED bits don't appear in the supported caps, but are implied
 by the corresponding FEC bits.

Signed-off-by: Edward Cree <ecree@solarflare.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/ethernet/sfc/mcdi_port_common.c b/drivers/net/ethernet/sfc/mcdi_port_common.c
index 71c76a6..c0e1c88 100644 (file)
--- a/drivers/net/ethernet/sfc/mcdi_port_common.c
+++ b/drivers/net/ethernet/sfc/mcdi_port_common.c
@@ -308,7 +308,7 @@ void efx_mcdi_phy_decode_link(struct efx_nic *efx,
  * Both RS and BASER (whether AUTO or not) means use FEC if cable and link
  * partner support it, preferring RS to BASER.
  */
-u32 ethtool_fec_caps_to_mcdi(u32 ethtool_cap)
+u32 ethtool_fec_caps_to_mcdi(u32 supported_cap, u32 ethtool_cap)
 {
        u32 ret = 0;
 
@@ -316,17 +316,21 @@ u32 ethtool_fec_caps_to_mcdi(u32 ethtool_cap)
                return 0;
 
        if (ethtool_cap & ETHTOOL_FEC_AUTO)
-               ret |= (1 << MC_CMD_PHY_CAP_BASER_FEC_LBN) |
-                      (1 << MC_CMD_PHY_CAP_25G_BASER_FEC_LBN) |
-                      (1 << MC_CMD_PHY_CAP_RS_FEC_LBN);
-       if (ethtool_cap & ETHTOOL_FEC_RS)
+               ret |= ((1 << MC_CMD_PHY_CAP_BASER_FEC_LBN) |
+                       (1 << MC_CMD_PHY_CAP_25G_BASER_FEC_LBN) |
+                       (1 << MC_CMD_PHY_CAP_RS_FEC_LBN)) & supported_cap;
+       if (ethtool_cap & ETHTOOL_FEC_RS &&
+           supported_cap & (1 << MC_CMD_PHY_CAP_RS_FEC_LBN))
                ret |= (1 << MC_CMD_PHY_CAP_RS_FEC_LBN) |
                       (1 << MC_CMD_PHY_CAP_RS_FEC_REQUESTED_LBN);
-       if (ethtool_cap & ETHTOOL_FEC_BASER)
-               ret |= (1 << MC_CMD_PHY_CAP_BASER_FEC_LBN) |
-                      (1 << MC_CMD_PHY_CAP_25G_BASER_FEC_LBN) |
-                      (1 << MC_CMD_PHY_CAP_BASER_FEC_REQUESTED_LBN) |
-                      (1 << MC_CMD_PHY_CAP_25G_BASER_FEC_REQUESTED_LBN);
+       if (ethtool_cap & ETHTOOL_FEC_BASER) {
+               if (supported_cap & (1 << MC_CMD_PHY_CAP_BASER_FEC_LBN))
+                       ret |= (1 << MC_CMD_PHY_CAP_BASER_FEC_LBN) |
+                              (1 << MC_CMD_PHY_CAP_BASER_FEC_REQUESTED_LBN);
+               if (supported_cap & (1 << MC_CMD_PHY_CAP_25G_BASER_FEC_LBN))
+                       ret |= (1 << MC_CMD_PHY_CAP_25G_BASER_FEC_LBN) |
+                              (1 << MC_CMD_PHY_CAP_25G_BASER_FEC_REQUESTED_LBN);
+       }
        return ret;
 }
 
@@ -577,7 +581,7 @@ int efx_mcdi_phy_set_link_ksettings(struct efx_nic *efx, const struct ethtool_li
                }
        }
 
-       caps |= ethtool_fec_caps_to_mcdi(efx->fec_config);
+       caps |= ethtool_fec_caps_to_mcdi(phy_cfg->supported_cap, efx->fec_config);
 
        rc = efx_mcdi_set_link(efx, caps, efx_get_mcdi_phy_flags(efx),
                               efx->loopback_mode, 0);
@@ -645,12 +649,30 @@ int efx_mcdi_phy_get_fecparam(struct efx_nic *efx, struct ethtool_fecparam *fec)
        return 0;
 }
 
+/* Basic validation to ensure that the caps we are going to attempt to set are
+ * in fact supported by the adapter.  Note that 'no FEC' is always supported.
+ */
+static int ethtool_fec_supported(u32 supported_cap, u32 ethtool_cap)
+{
+       if (ethtool_cap & ETHTOOL_FEC_OFF)
+               return 0;
+
+       if (ethtool_cap &&
+           !ethtool_fec_caps_to_mcdi(supported_cap, ethtool_cap))
+               return -EINVAL;
+       return 0;
+}
+
 int efx_mcdi_phy_set_fecparam(struct efx_nic *efx, const struct ethtool_fecparam *fec)
 {
        struct efx_mcdi_phy_data *phy_cfg = efx->phy_data;
        u32 caps;
        int rc;
 
+       rc = ethtool_fec_supported(phy_cfg->supported_cap, fec->fec);
+       if (rc)
+               return rc;
+
        /* Work out what efx_mcdi_phy_set_link_ksettings() would produce from
         * saved advertising bits
         */
@@ -660,7 +682,7 @@ int efx_mcdi_phy_set_fecparam(struct efx_nic *efx, const struct ethtool_fecparam
        else
                caps = phy_cfg->forced_cap;
 
-       caps |= ethtool_fec_caps_to_mcdi(fec->fec);
+       caps |= ethtool_fec_caps_to_mcdi(phy_cfg->supported_cap, fec->fec);
        rc = efx_mcdi_set_link(efx, caps, efx_get_mcdi_phy_flags(efx),
                               efx->loopback_mode, 0);
        if (rc)
@@ -699,7 +721,7 @@ int efx_mcdi_port_reconfigure(struct efx_nic *efx)
                    ethtool_linkset_to_mcdi_cap(efx->link_advertising) :
                    phy_cfg->forced_cap);
 
-       caps |= ethtool_fec_caps_to_mcdi(efx->fec_config);
+       caps |= ethtool_fec_caps_to_mcdi(phy_cfg->supported_cap, efx->fec_config);
 
        return efx_mcdi_set_link(efx, caps, efx_get_mcdi_phy_flags(efx),
                                 efx->loopback_mode, 0);

diff --git a/drivers/net/ethernet/sfc/mcdi_port_common.h b/drivers/net/ethernet/sfc/mcdi_port_common.h
index 9d21407..f37e18a 100644 (file)
--- a/drivers/net/ethernet/sfc/mcdi_port_common.h
+++ b/drivers/net/ethernet/sfc/mcdi_port_common.h
@@ -41,7 +41,7 @@ u8 mcdi_to_ethtool_media(u32 media);
 void efx_mcdi_phy_decode_link(struct efx_nic *efx,
                              struct efx_link_state *link_state,
                              u32 speed, u32 flags, u32 fcntl);
-u32 ethtool_fec_caps_to_mcdi(u32 ethtool_cap);
+u32 ethtool_fec_caps_to_mcdi(u32 supported_cap, u32 ethtool_cap);
 u32 mcdi_fec_caps_to_ethtool(u32 caps, bool is_25g);
 void efx_mcdi_phy_check_fcntl(struct efx_nic *efx, u32 lpa);
 bool efx_mcdi_phy_poll(struct efx_nic *efx);