[PATCH iwl-next v4 0/3] igc: add support for forcing link speed without autonegotiation

[PATCH iwl-next v4 0/3] igc: add support for forcing link speed without autonegotiation

[KhaiWenTan]

From: Faizal Rahim <faizal.abdul.rahim@linux.intel.com>

This series adds support for forcing 10/100 Mb/s link speed via ethtool
when autonegotiation is disabled on the igc driver.

Changes in v4:
- Validate that autoneg is AUTONEG_ENABLE or AUTONEG_DISABLE early
  in igc_ethtool_set_link_ksettings() to avoid passing unexpected
  values to igc_handle_autoneg_disabled(). (Simon Horman)

Changes in v3:
- Modify condition from "if (duplex == DUPLEX_HALF)" to
  "if (duplex != DUPLEX_FULL)". (Simon Horman)

Changes in v2:
- When forcing half-duplex, set hw->fc.requested_mode = igc_fc_none,
  since half-duplex cannot support flow control per IEEE 802.3.
  (Simon Horman)
- Split the original single patch into three patches for clarity:
  patches 1 and 2 are preparatory cleanups; patch 3 carries the
  functional change.

v3 at:
https://patchwork.ozlabs.org/project/intel-wired-lan/cover/20260422155701.7420-1-khai.wen.tan@linux.intel.com/

v2 at:
https://patchwork.kernel.org/project/netdevbpf/patch/20260416015520.6090-4-khai.wen.tan@linux.intel.com/

v1 at:
https://patchwork.ozlabs.org/project/intel-wired-lan/patch/20260409072747.217836-1-khai.wen.tan@linux.intel.com/

Faizal Rahim (3):
  igc: remove unused autoneg_failed field
  igc: move autoneg-enabled settings into igc_handle_autoneg_enabled()
  igc: add support for forcing link speed without autonegotiation

 drivers/net/ethernet/intel/igc/igc_base.c    |  35 +++-
 drivers/net/ethernet/intel/igc/igc_defines.h |   9 +-
 drivers/net/ethernet/intel/igc/igc_ethtool.c | 209 +++++++++++++------
 drivers/net/ethernet/intel/igc/igc_hw.h      |  10 +-
 drivers/net/ethernet/intel/igc/igc_mac.c     |  16 +-
 drivers/net/ethernet/intel/igc/igc_main.c    |   2 +-
 drivers/net/ethernet/intel/igc/igc_phy.c     |  65 +++++-
 drivers/net/ethernet/intel/igc/igc_phy.h     |   1 +
 8 files changed, 257 insertions(+), 90 deletions(-)

--
2.43.0

[PATCH iwl-next v4 1/3] igc: remove unused autoneg_failed field

[KhaiWenTan]

From: Faizal Rahim <faizal.abdul.rahim@linux.intel.com>

autoneg_failed in struct igc_mac_info is never set in the igc driver.
Remove the field and the dead code checking it in
igc_config_fc_after_link_up().

Reviewed-by: Looi, Hong Aun <hong.aun.looi@intel.com>
Reviewed-by: Aleksandr Loktionov <aleksandr.loktionov@intel.com>
Signed-off-by: Faizal Rahim <faizal.abdul.rahim@linux.intel.com>
Signed-off-by: KhaiWenTan <khai.wen.tan@linux.intel.com>
---
 drivers/net/ethernet/intel/igc/igc_hw.h  |  1 -
 drivers/net/ethernet/intel/igc/igc_mac.c | 16 +---------------
 2 files changed, 1 insertion(+), 16 deletions(-)

diff --git a/drivers/net/ethernet/intel/igc/igc_hw.h b/drivers/net/ethernet/intel/igc/igc_hw.h
index be8a49a86d09..86ab8f566f44 100644
--- a/drivers/net/ethernet/intel/igc/igc_hw.h
+++ b/drivers/net/ethernet/intel/igc/igc_hw.h
@@ -92,7 +92,6 @@ struct igc_mac_info {
 	bool asf_firmware_present;
 	bool arc_subsystem_valid;

-	bool autoneg_failed;
 	bool get_link_status;
 };

diff --git a/drivers/net/ethernet/intel/igc/igc_mac.c b/drivers/net/ethernet/intel/igc/igc_mac.c
index 7ac6637f8db7..142beb9ae557 100644
--- a/drivers/net/ethernet/intel/igc/igc_mac.c
+++ b/drivers/net/ethernet/intel/igc/igc_mac.c
@@ -438,28 +438,14 @@ void igc_config_collision_dist(struct igc_hw *hw)
  * Checks the status of auto-negotiation after link up to ensure that the
  * speed and duplex were not forced.  If the link needed to be forced, then
  * flow control needs to be forced also.  If auto-negotiation is enabled
- * and did not fail, then we configure flow control based on our link
- * partner.
+ * then we configure flow control based on our link partner.
  */
 s32 igc_config_fc_after_link_up(struct igc_hw *hw)
 {
 	u16 mii_status_reg, mii_nway_adv_reg, mii_nway_lp_ability_reg;
-	struct igc_mac_info *mac = &hw->mac;
 	u16 speed, duplex;
 	s32 ret_val = 0;

-	/* Check for the case where we have fiber media and auto-neg failed
-	 * so we had to force link.  In this case, we need to force the
-	 * configuration of the MAC to match the "fc" parameter.
-	 */
-	if (mac->autoneg_failed)
-		ret_val = igc_force_mac_fc(hw);
-
-	if (ret_val) {
-		hw_dbg("Error forcing flow control settings\n");
-		goto out;
-	}
-
 	/* In auto-neg, we need to check and see if Auto-Neg has completed,
 	 * and if so, how the PHY and link partner has flow control
 	 * configured.
--
2.43.0

Re: [Intel-wired-lan] [PATCH iwl-next v4 1/3] igc: remove unused autoneg_failed field

[Paul Menzel]

[Cc: Removed stray *Looi*]

Dear Khai Wen Tan,


Thank you for your patch.


Am 28.04.26 um 08:00 schrieb KhaiWenTan:

(Should spaces be added in your name?)

> From: Faizal Rahim <faizal.abdul.rahim@linux.intel.com>
> 
> autoneg_failed in struct igc_mac_info is never set in the igc driver.
> Remove the field and the dead code checking it in
> igc_config_fc_after_link_up().

Could you please elaborate. Why is removal the correct fix, and it’s not 
an incomplete feature? Does auto-negotiation always succeed?

> Reviewed-by: Looi, Hong Aun <hong.aun.looi@intel.com>

Please order it to not use the comma: Hong Aun Looi

> Reviewed-by: Aleksandr Loktionov <aleksandr.loktionov@intel.com>
> Signed-off-by: Faizal Rahim <faizal.abdul.rahim@linux.intel.com>
> Signed-off-by: KhaiWenTan <khai.wen.tan@linux.intel.com>
> ---
>   drivers/net/ethernet/intel/igc/igc_hw.h  |  1 -
>   drivers/net/ethernet/intel/igc/igc_mac.c | 16 +---------------
>   2 files changed, 1 insertion(+), 16 deletions(-)
> 
> diff --git a/drivers/net/ethernet/intel/igc/igc_hw.h b/drivers/net/ethernet/intel/igc/igc_hw.h
> index be8a49a86d09..86ab8f566f44 100644
> --- a/drivers/net/ethernet/intel/igc/igc_hw.h
> +++ b/drivers/net/ethernet/intel/igc/igc_hw.h
> @@ -92,7 +92,6 @@ struct igc_mac_info {
>   	bool asf_firmware_present;
>   	bool arc_subsystem_valid;
> 
> -	bool autoneg_failed;
>   	bool get_link_status;
>   };
> 
> diff --git a/drivers/net/ethernet/intel/igc/igc_mac.c b/drivers/net/ethernet/intel/igc/igc_mac.c
> index 7ac6637f8db7..142beb9ae557 100644
> --- a/drivers/net/ethernet/intel/igc/igc_mac.c
> +++ b/drivers/net/ethernet/intel/igc/igc_mac.c
> @@ -438,28 +438,14 @@ void igc_config_collision_dist(struct igc_hw *hw)
>    * Checks the status of auto-negotiation after link up to ensure that the
>    * speed and duplex were not forced.  If the link needed to be forced, then
>    * flow control needs to be forced also.  If auto-negotiation is enabled
> - * and did not fail, then we configure flow control based on our link
> - * partner.
> + * then we configure flow control based on our link partner.
>    */
>   s32 igc_config_fc_after_link_up(struct igc_hw *hw)
>   {
>   	u16 mii_status_reg, mii_nway_adv_reg, mii_nway_lp_ability_reg;
> -	struct igc_mac_info *mac = &hw->mac;
>   	u16 speed, duplex;
>   	s32 ret_val = 0;
> 
> -	/* Check for the case where we have fiber media and auto-neg failed
> -	 * so we had to force link.  In this case, we need to force the
> -	 * configuration of the MAC to match the "fc" parameter.
> -	 */
> -	if (mac->autoneg_failed)
> -		ret_val = igc_force_mac_fc(hw);
> -
> -	if (ret_val) {
> -		hw_dbg("Error forcing flow control settings\n");
> -		goto out;
> -	}
> -
>   	/* In auto-neg, we need to check and see if Auto-Neg has completed,
>   	 * and if so, how the PHY and link partner has flow control
>   	 * configured.


Kind regards,

Paul

Re: [Intel-wired-lan] [PATCH iwl-next v4 1/3] igc: remove unused autoneg_failed field

[Abdul Rahim, Faizal]

Hi Paul,

Thank you for your review.

On 28/4/2026 2:56 pm, Paul Menzel wrote:
> [Cc: Removed stray *Looi*]
> 
> Dear Khai Wen Tan,
> 
> 
> Thank you for your patch.
> 
> 
> Am 28.04.26 um 08:00 schrieb KhaiWenTan:
> 
> (Should spaces be added in your name?)
> 
>> From: Faizal Rahim <faizal.abdul.rahim@linux.intel.com>
>>
>> autoneg_failed in struct igc_mac_info is never set in the igc driver.
>> Remove the field and the dead code checking it in
>> igc_config_fc_after_link_up().
> 
> Could you please elaborate. Why is removal the correct fix, and it’s not an 
> incomplete feature? Does auto-negotiation always succeed?
> 

Auto-negotiation does not always succeed, but igc does not use
autoneg_failed to handle that case, the field was never set anywhere
in the igc driver.

Before this patch, the only igc references to autoneg_failed were
the struct member declaration and the read in
igc_config_fc_after_link_up(). No igc code ever assigned it to true,
and git history shows no commit that added a setter since the code
creation in 2018.

The field originates from the e1000/e1000e fiber/serdes forced-link
path: when MAC-level auto-negotiation on fiber times out, the driver
forces link up and sets autoneg_failed so the flow-control code knows
pause was not negotiated and must be forced. igc has no fiber or
serdes media, it only supports copper (igc_media_type_copper), so
the code that sets autoneg_failed was never ported.

On copper, PHY auto-negotiation failure is handled differently:
- No link at all: igc_check_for_copper_link() returns before reaching
   flow-control configuration, there's nothing to configure FC on.
- Link present but autoneg not yet complete:
   igc_config_fc_after_link_up() checks MII_SR_AUTONEG_COMPLETE and
   returns early without resolving pause. The next link-status event
   re-triggers the check.
- Autoneg completes (including via parallel detection fallback when
   the link partner doesn't autoneg): the PHY still sets
   AUTONEG_COMPLETE but LP_ABILITY won't have PAUSE bits since the
   partner never sent autoneg pages. The existing flow-control logic
   in igc_config_fc_after_link_up() handles that correctly, it falls
   through to igc_fc_none or igc_fc_rx_pause based on requested_mode.

None of these paths need autoneg_failed. Keeping the field would be 
misleading to reader.


>> Reviewed-by: Looi, Hong Aun <hong.aun.looi@intel.com>
> 
> Please order it to not use the comma: Hong Aun Looi
> 

Will do, thanks.

>> Reviewed-by: Aleksandr Loktionov <aleksandr.loktionov@intel.com>
>> Signed-off-by: Faizal Rahim <faizal.abdul.rahim@linux.intel.com>
>> Signed-off-by: KhaiWenTan <khai.wen.tan@linux.intel.com>
>> ---
>>   drivers/net/ethernet/intel/igc/igc_hw.h  |  1 -
>>   drivers/net/ethernet/intel/igc/igc_mac.c | 16 +---------------
>>   2 files changed, 1 insertion(+), 16 deletions(-)
>>
>> diff --git a/drivers/net/ethernet/intel/igc/igc_hw.h b/drivers/net/ 
>> ethernet/intel/igc/igc_hw.h
>> index be8a49a86d09..86ab8f566f44 100644
>> --- a/drivers/net/ethernet/intel/igc/igc_hw.h
>> +++ b/drivers/net/ethernet/intel/igc/igc_hw.h
>> @@ -92,7 +92,6 @@ struct igc_mac_info {
>>       bool asf_firmware_present;
>>       bool arc_subsystem_valid;
>>
>> -    bool autoneg_failed;
>>       bool get_link_status;
>>   };
>>
>> diff --git a/drivers/net/ethernet/intel/igc/igc_mac.c b/drivers/net/ 
>> ethernet/intel/igc/igc_mac.c
>> index 7ac6637f8db7..142beb9ae557 100644
>> --- a/drivers/net/ethernet/intel/igc/igc_mac.c
>> +++ b/drivers/net/ethernet/intel/igc/igc_mac.c
>> @@ -438,28 +438,14 @@ void igc_config_collision_dist(struct igc_hw *hw)
>>    * Checks the status of auto-negotiation after link up to ensure that the
>>    * speed and duplex were not forced.  If the link needed to be forced, 
>> then
>>    * flow control needs to be forced also.  If auto-negotiation is enabled
>> - * and did not fail, then we configure flow control based on our link
>> - * partner.
>> + * then we configure flow control based on our link partner.
>>    */
>>   s32 igc_config_fc_after_link_up(struct igc_hw *hw)
>>   {
>>       u16 mii_status_reg, mii_nway_adv_reg, mii_nway_lp_ability_reg;
>> -    struct igc_mac_info *mac = &hw->mac;
>>       u16 speed, duplex;
>>       s32 ret_val = 0;
>>
>> -    /* Check for the case where we have fiber media and auto-neg failed
>> -     * so we had to force link.  In this case, we need to force the
>> -     * configuration of the MAC to match the "fc" parameter.
>> -     */
>> -    if (mac->autoneg_failed)
>> -        ret_val = igc_force_mac_fc(hw);
>> -
>> -    if (ret_val) {
>> -        hw_dbg("Error forcing flow control settings\n");
>> -        goto out;
>> -    }
>> -
>>       /* In auto-neg, we need to check and see if Auto-Neg has completed,
>>        * and if so, how the PHY and link partner has flow control
>>        * configured.
> 
> 
> Kind regards,
> 
> Paul
> 

Re: [Intel-wired-lan] [PATCH iwl-next v4 1/3] igc: remove unused autoneg_failed field

[Paul Menzel]

Dear Faizal,


Am 28.04.26 um 12:39 schrieb Abdul Rahim, Faizal:

> On 28/4/2026 2:56 pm, Paul Menzel wrote:

>> Am 28.04.26 um 08:00 schrieb KhaiWenTan:
>>
>> (Should spaces be added in your name?)
>>
>>> From: Faizal Rahim <faizal.abdul.rahim@linux.intel.com>
>>>
>>> autoneg_failed in struct igc_mac_info is never set in the igc driver.
>>> Remove the field and the dead code checking it in
>>> igc_config_fc_after_link_up().
>>
>> Could you please elaborate. Why is removal the correct fix, and it’s 
>> not an incomplete feature? Does auto-negotiation always succeed?
> 
> Auto-negotiation does not always succeed, but igc does not use
> autoneg_failed to handle that case, the field was never set anywhere
> in the igc driver.
> 
> Before this patch, the only igc references to autoneg_failed were
> the struct member declaration and the read in
> igc_config_fc_after_link_up(). No igc code ever assigned it to true,
> and git history shows no commit that added a setter since the code
> creation in 2018.
> 
> The field originates from the e1000/e1000e fiber/serdes forced-link
> path: when MAC-level auto-negotiation on fiber times out, the driver
> forces link up and sets autoneg_failed so the flow-control code knows
> pause was not negotiated and must be forced. igc has no fiber or
> serdes media, it only supports copper (igc_media_type_copper), so
> the code that sets autoneg_failed was never ported.
> 
> On copper, PHY auto-negotiation failure is handled differently:
> - No link at all: igc_check_for_copper_link() returns before reaching
>    flow-control configuration, there's nothing to configure FC on.
> - Link present but autoneg not yet complete:
>    igc_config_fc_after_link_up() checks MII_SR_AUTONEG_COMPLETE and
>    returns early without resolving pause. The next link-status event
>    re-triggers the check.
> - Autoneg completes (including via parallel detection fallback when
>    the link partner doesn't autoneg): the PHY still sets
>    AUTONEG_COMPLETE but LP_ABILITY won't have PAUSE bits since the
>    partner never sent autoneg pages. The existing flow-control logic
>    in igc_config_fc_after_link_up() handles that correctly, it falls
>    through to igc_fc_none or igc_fc_rx_pause based on requested_mode.
> 
> None of these paths need autoneg_failed. Keeping the field would be 
> misleading to reader.

Thank you. For me the information about just supporting copper would be 
great to have in the commit message.

>>> Reviewed-by: Looi, Hong Aun <hong.aun.looi@intel.com>
>>
>> Please order it to not use the comma: Hong Aun Looi
> 
> Will do, thanks.
> 
>>> Reviewed-by: Aleksandr Loktionov <aleksandr.loktionov@intel.com>
>>> Signed-off-by: Faizal Rahim <faizal.abdul.rahim@linux.intel.com>
>>> Signed-off-by: KhaiWenTan <khai.wen.tan@linux.intel.com>
>>> ---
>>>   drivers/net/ethernet/intel/igc/igc_hw.h  |  1 -
>>>   drivers/net/ethernet/intel/igc/igc_mac.c | 16 +---------------
>>>   2 files changed, 1 insertion(+), 16 deletions(-)
>>>
>>> diff --git a/drivers/net/ethernet/intel/igc/igc_hw.h b/drivers/net/ 
>>> ethernet/intel/igc/igc_hw.h
>>> index be8a49a86d09..86ab8f566f44 100644
>>> --- a/drivers/net/ethernet/intel/igc/igc_hw.h
>>> +++ b/drivers/net/ethernet/intel/igc/igc_hw.h
>>> @@ -92,7 +92,6 @@ struct igc_mac_info {
>>>       bool asf_firmware_present;
>>>       bool arc_subsystem_valid;
>>>
>>> -    bool autoneg_failed;
>>>       bool get_link_status;
>>>   };
>>>
>>> diff --git a/drivers/net/ethernet/intel/igc/igc_mac.c b/drivers/net/ 
>>> ethernet/intel/igc/igc_mac.c
>>> index 7ac6637f8db7..142beb9ae557 100644
>>> --- a/drivers/net/ethernet/intel/igc/igc_mac.c
>>> +++ b/drivers/net/ethernet/intel/igc/igc_mac.c
>>> @@ -438,28 +438,14 @@ void igc_config_collision_dist(struct igc_hw *hw)
>>>    * Checks the status of auto-negotiation after link up to ensure 
>>> that the

Just for your information, that your mailer wraps the lines of the quotes.

[…]

>>>    * speed and duplex were not forced.  If the link needed to be 
>>> forced, then
>>>    * flow control needs to be forced also.  If auto-negotiation is 
>>> enabled
>>> - * and did not fail, then we configure flow control based on our link
>>> - * partner.
>>> + * then we configure flow control based on our link partner.
>>>    */
>>>   s32 igc_config_fc_after_link_up(struct igc_hw *hw)
>>>   {
>>>       u16 mii_status_reg, mii_nway_adv_reg, mii_nway_lp_ability_reg;
>>> -    struct igc_mac_info *mac = &hw->mac;
>>>       u16 speed, duplex;
>>>       s32 ret_val = 0;
>>>
>>> -    /* Check for the case where we have fiber media and auto-neg failed
>>> -     * so we had to force link.  In this case, we need to force the
>>> -     * configuration of the MAC to match the "fc" parameter.
>>> -     */
>>> -    if (mac->autoneg_failed)
>>> -        ret_val = igc_force_mac_fc(hw);
>>> -
>>> -    if (ret_val) {
>>> -        hw_dbg("Error forcing flow control settings\n");
>>> -        goto out;
>>> -    }
>>> -
>>>       /* In auto-neg, we need to check and see if Auto-Neg has 
>>> completed,
>>>        * and if so, how the PHY and link partner has flow control
>>>        * configured.

Kind regards,

Paul

[PATCH iwl-next v4 2/3] igc: move autoneg-enabled settings into igc_handle_autoneg_enabled()

[KhaiWenTan]

From: Faizal Rahim <faizal.abdul.rahim@linux.intel.com>

Move the advertised link modes and flow control configuration from
igc_ethtool_set_link_ksettings() into igc_handle_autoneg_enabled().

No functional change.

Reviewed-by: Looi, Hong Aun <hong.aun.looi@intel.com>
Reviewed-by: Aleksandr Loktionov <aleksandr.loktionov@intel.com>
Signed-off-by: Faizal Rahim <faizal.abdul.rahim@linux.intel.com>
Signed-off-by: KhaiWenTan <khai.wen.tan@linux.intel.com>
---
 drivers/net/ethernet/intel/igc/igc_ethtool.c | 72 ++++++++++++--------
 1 file changed, 44 insertions(+), 28 deletions(-)

diff --git a/drivers/net/ethernet/intel/igc/igc_ethtool.c b/drivers/net/ethernet/intel/igc/igc_ethtool.c
index 0122009bedd0..cfcbf2fdad6e 100644
--- a/drivers/net/ethernet/intel/igc/igc_ethtool.c
+++ b/drivers/net/ethernet/intel/igc/igc_ethtool.c
@@ -2000,6 +2000,49 @@ static int igc_ethtool_get_link_ksettings(struct net_device *netdev,
 	return 0;
 }

+/**
+ * igc_handle_autoneg_enabled - Configure autonegotiation advertisement
+ * @adapter: private driver structure
+ * @cmd: ethtool link ksettings from user
+ *
+ * Records advertised speeds and flow control settings when autoneg
+ * is enabled.
+ */
+static void igc_handle_autoneg_enabled(struct igc_adapter *adapter,
+				       const struct ethtool_link_ksettings *cmd)
+{
+	struct igc_hw *hw = &adapter->hw;
+	u16 advertised = 0;
+
+	if (ethtool_link_ksettings_test_link_mode(cmd, advertising,
+						  2500baseT_Full))
+		advertised |= ADVERTISE_2500_FULL;
+
+	if (ethtool_link_ksettings_test_link_mode(cmd, advertising,
+						  1000baseT_Full))
+		advertised |= ADVERTISE_1000_FULL;
+
+	if (ethtool_link_ksettings_test_link_mode(cmd, advertising,
+						  100baseT_Full))
+		advertised |= ADVERTISE_100_FULL;
+
+	if (ethtool_link_ksettings_test_link_mode(cmd, advertising,
+						  100baseT_Half))
+		advertised |= ADVERTISE_100_HALF;
+
+	if (ethtool_link_ksettings_test_link_mode(cmd, advertising,
+						  10baseT_Full))
+		advertised |= ADVERTISE_10_FULL;
+
+	if (ethtool_link_ksettings_test_link_mode(cmd, advertising,
+						  10baseT_Half))
+		advertised |= ADVERTISE_10_HALF;
+
+	hw->phy.autoneg_advertised = advertised;
+	if (adapter->fc_autoneg)
+		hw->fc.requested_mode = igc_fc_default;
+}
+
 static int
 igc_ethtool_set_link_ksettings(struct net_device *netdev,
 			       const struct ethtool_link_ksettings *cmd)
@@ -2007,7 +2050,6 @@ igc_ethtool_set_link_ksettings(struct net_device *netdev,
 	struct igc_adapter *adapter = netdev_priv(netdev);
 	struct net_device *dev = adapter->netdev;
 	struct igc_hw *hw = &adapter->hw;
-	u16 advertised = 0;

 	/* When adapter in resetting mode, autoneg/speed/duplex
 	 * cannot be changed
@@ -2032,34 +2074,8 @@ igc_ethtool_set_link_ksettings(struct net_device *netdev,
 	while (test_and_set_bit(__IGC_RESETTING, &adapter->state))
 		usleep_range(1000, 2000);

-	if (ethtool_link_ksettings_test_link_mode(cmd, advertising,
-						  2500baseT_Full))
-		advertised |= ADVERTISE_2500_FULL;
-
-	if (ethtool_link_ksettings_test_link_mode(cmd, advertising,
-						  1000baseT_Full))
-		advertised |= ADVERTISE_1000_FULL;
-
-	if (ethtool_link_ksettings_test_link_mode(cmd, advertising,
-						  100baseT_Full))
-		advertised |= ADVERTISE_100_FULL;
-
-	if (ethtool_link_ksettings_test_link_mode(cmd, advertising,
-						  100baseT_Half))
-		advertised |= ADVERTISE_100_HALF;
-
-	if (ethtool_link_ksettings_test_link_mode(cmd, advertising,
-						  10baseT_Full))
-		advertised |= ADVERTISE_10_FULL;
-
-	if (ethtool_link_ksettings_test_link_mode(cmd, advertising,
-						  10baseT_Half))
-		advertised |= ADVERTISE_10_HALF;
-
 	if (cmd->base.autoneg == AUTONEG_ENABLE) {
-		hw->phy.autoneg_advertised = advertised;
-		if (adapter->fc_autoneg)
-			hw->fc.requested_mode = igc_fc_default;
+		igc_handle_autoneg_enabled(adapter, cmd);
 	} else {
 		netdev_info(dev, "Force mode currently not supported\n");
 	}
--
2.43.0

[PATCH iwl-next v4 3/3] igc: add support for forcing link speed without autonegotiation

[KhaiWenTan]

From: Faizal Rahim <faizal.abdul.rahim@linux.intel.com>

Allow users to force 10/100 Mb/s link speed and duplex via ethtool
when autonegotiation is disabled. Previously, the driver rejected
these requests with "Force mode currently not supported.".

Forcing at 1000 Mb/s and 2500 Mb/s is not supported.

Reviewed-by: Looi, Hong Aun <hong.aun.looi@intel.com>
Signed-off-by: Faizal Rahim <faizal.abdul.rahim@linux.intel.com>
Signed-off-by: KhaiWenTan <khai.wen.tan@linux.intel.com>
---
 drivers/net/ethernet/intel/igc/igc_base.c    |  35 ++++-
 drivers/net/ethernet/intel/igc/igc_defines.h |   9 +-
 drivers/net/ethernet/intel/igc/igc_ethtool.c | 137 ++++++++++++++-----
 drivers/net/ethernet/intel/igc/igc_hw.h      |   9 ++
 drivers/net/ethernet/intel/igc/igc_mac.c     |  10 ++
 drivers/net/ethernet/intel/igc/igc_main.c    |   2 +-
 drivers/net/ethernet/intel/igc/igc_phy.c     |  65 ++++++++-
 drivers/net/ethernet/intel/igc/igc_phy.h     |   1 +
 8 files changed, 217 insertions(+), 51 deletions(-)

diff --git a/drivers/net/ethernet/intel/igc/igc_base.c b/drivers/net/ethernet/intel/igc/igc_base.c
index 1613b562d17c..ab9120a3127f 100644
--- a/drivers/net/ethernet/intel/igc/igc_base.c
+++ b/drivers/net/ethernet/intel/igc/igc_base.c
@@ -114,11 +114,35 @@ static s32 igc_setup_copper_link_base(struct igc_hw *hw)
 	u32 ctrl;
 
 	ctrl = rd32(IGC_CTRL);
-	ctrl |= IGC_CTRL_SLU;
-	ctrl &= ~(IGC_CTRL_FRCSPD | IGC_CTRL_FRCDPX);
-	wr32(IGC_CTRL, ctrl);
-
-	ret_val = igc_setup_copper_link(hw);
+	ctrl &= ~(IGC_CTRL_FRCSPD | IGC_CTRL_FRCDPX |
+		  IGC_CTRL_SPEED_MASK | IGC_CTRL_FD);
+
+	if (hw->mac.autoneg_enabled) {
+		ctrl |= IGC_CTRL_SLU;
+		wr32(IGC_CTRL, ctrl);
+		ret_val = igc_setup_copper_link(hw);
+	} else {
+		ctrl |= IGC_CTRL_SLU | IGC_CTRL_FRCSPD | IGC_CTRL_FRCDPX;
+
+		switch (hw->mac.forced_speed_duplex) {
+		case IGC_FORCED_10H:
+			ctrl |= IGC_CTRL_SPEED_10;
+			break;
+		case IGC_FORCED_10F:
+			ctrl |= IGC_CTRL_SPEED_10 | IGC_CTRL_FD;
+			break;
+		case IGC_FORCED_100H:
+			ctrl |= IGC_CTRL_SPEED_100;
+			break;
+		case IGC_FORCED_100F:
+			ctrl |= IGC_CTRL_SPEED_100 | IGC_CTRL_FD;
+			break;
+		default:
+			return -IGC_ERR_CONFIG;
+		}
+		wr32(IGC_CTRL, ctrl);
+		ret_val = igc_setup_copper_link(hw);
+	}
 
 	return ret_val;
 }
@@ -443,6 +467,7 @@ static const struct igc_phy_operations igc_phy_ops_base = {
 	.reset			= igc_phy_hw_reset,
 	.read_reg		= igc_read_phy_reg_gpy,
 	.write_reg		= igc_write_phy_reg_gpy,
+	.force_speed_duplex	= igc_force_speed_duplex,
 };
 
 const struct igc_info igc_base_info = {
diff --git a/drivers/net/ethernet/intel/igc/igc_defines.h b/drivers/net/ethernet/intel/igc/igc_defines.h
index 9482ab11f050..3f504751c2d9 100644
--- a/drivers/net/ethernet/intel/igc/igc_defines.h
+++ b/drivers/net/ethernet/intel/igc/igc_defines.h
@@ -129,10 +129,13 @@
 #define IGC_ERR_SWFW_SYNC		13
 
 /* Device Control */
+#define IGC_CTRL_FD		BIT(0)  /* Full Duplex */
 #define IGC_CTRL_RST		0x04000000  /* Global reset */
-
 #define IGC_CTRL_PHY_RST	0x80000000  /* PHY Reset */
 #define IGC_CTRL_SLU		0x00000040  /* Set link up (Force Link) */
+#define IGC_CTRL_SPEED_MASK	GENMASK(10, 8)
+#define IGC_CTRL_SPEED_10	FIELD_PREP(IGC_CTRL_SPEED_MASK, 0)
+#define IGC_CTRL_SPEED_100	FIELD_PREP(IGC_CTRL_SPEED_MASK, 1)
 #define IGC_CTRL_FRCSPD		0x00000800  /* Force Speed */
 #define IGC_CTRL_FRCDPX		0x00001000  /* Force Duplex */
 #define IGC_CTRL_VME		0x40000000  /* IEEE VLAN mode enable */
@@ -673,6 +676,10 @@
 #define IGC_GEN_POLL_TIMEOUT	1920
 
 /* PHY Control Register */
+#define MII_CR_SPEED_MASK	(BIT(6) | BIT(13))
+#define MII_CR_SPEED_10		0x0000	/* SSM=0, SSL=0: 10 Mb/s */
+#define MII_CR_SPEED_100	BIT(13)	/* SSM=0, SSL=1: 100 Mb/s */
+#define MII_CR_DUPLEX_EN	BIT(8)	/* 0 = Half Duplex, 1 = Full Duplex */
 #define MII_CR_RESTART_AUTO_NEG	0x0200  /* Restart auto negotiation */
 #define MII_CR_POWER_DOWN	0x0800  /* Power down */
 #define MII_CR_AUTO_NEG_EN	0x1000  /* Auto Neg Enable */
diff --git a/drivers/net/ethernet/intel/igc/igc_ethtool.c b/drivers/net/ethernet/intel/igc/igc_ethtool.c
index cfcbf2fdad6e..9997ebbdf778 100644
--- a/drivers/net/ethernet/intel/igc/igc_ethtool.c
+++ b/drivers/net/ethernet/intel/igc/igc_ethtool.c
@@ -1914,44 +1914,58 @@ static int igc_ethtool_get_link_ksettings(struct net_device *netdev,
 	ethtool_link_ksettings_add_link_mode(cmd, supported, TP);
 	ethtool_link_ksettings_add_link_mode(cmd, advertising, TP);
 
-	/* advertising link modes */
-	if (hw->phy.autoneg_advertised & ADVERTISE_10_HALF)
-		ethtool_link_ksettings_add_link_mode(cmd, advertising, 10baseT_Half);
-	if (hw->phy.autoneg_advertised & ADVERTISE_10_FULL)
-		ethtool_link_ksettings_add_link_mode(cmd, advertising, 10baseT_Full);
-	if (hw->phy.autoneg_advertised & ADVERTISE_100_HALF)
-		ethtool_link_ksettings_add_link_mode(cmd, advertising, 100baseT_Half);
-	if (hw->phy.autoneg_advertised & ADVERTISE_100_FULL)
-		ethtool_link_ksettings_add_link_mode(cmd, advertising, 100baseT_Full);
-	if (hw->phy.autoneg_advertised & ADVERTISE_1000_FULL)
-		ethtool_link_ksettings_add_link_mode(cmd, advertising, 1000baseT_Full);
-	if (hw->phy.autoneg_advertised & ADVERTISE_2500_FULL)
-		ethtool_link_ksettings_add_link_mode(cmd, advertising, 2500baseT_Full);
-
 	/* set autoneg settings */
 	ethtool_link_ksettings_add_link_mode(cmd, supported, Autoneg);
-	ethtool_link_ksettings_add_link_mode(cmd, advertising, Autoneg);
+	if (hw->mac.autoneg_enabled) {
+		ethtool_link_ksettings_add_link_mode(cmd, advertising, Autoneg);
+		cmd->base.autoneg = AUTONEG_ENABLE;
+
+		/* advertising link modes only apply when autoneg is on */
+		if (hw->phy.autoneg_advertised & ADVERTISE_10_HALF)
+			ethtool_link_ksettings_add_link_mode(cmd, advertising,
+							     10baseT_Half);
+		if (hw->phy.autoneg_advertised & ADVERTISE_10_FULL)
+			ethtool_link_ksettings_add_link_mode(cmd, advertising,
+							     10baseT_Full);
+		if (hw->phy.autoneg_advertised & ADVERTISE_100_HALF)
+			ethtool_link_ksettings_add_link_mode(cmd, advertising,
+							     100baseT_Half);
+		if (hw->phy.autoneg_advertised & ADVERTISE_100_FULL)
+			ethtool_link_ksettings_add_link_mode(cmd, advertising,
+							     100baseT_Full);
+		if (hw->phy.autoneg_advertised & ADVERTISE_1000_FULL)
+			ethtool_link_ksettings_add_link_mode(cmd, advertising,
+							     1000baseT_Full);
+		if (hw->phy.autoneg_advertised & ADVERTISE_2500_FULL)
+			ethtool_link_ksettings_add_link_mode(cmd, advertising,
+							     2500baseT_Full);
+
+		/* Set pause flow control advertising */
+		switch (hw->fc.requested_mode) {
+		case igc_fc_full:
+			ethtool_link_ksettings_add_link_mode(cmd, advertising,
+							     Pause);
+			break;
+		case igc_fc_rx_pause:
+			ethtool_link_ksettings_add_link_mode(cmd, advertising,
+							     Pause);
+			ethtool_link_ksettings_add_link_mode(cmd, advertising,
+							     Asym_Pause);
+			break;
+		case igc_fc_tx_pause:
+			ethtool_link_ksettings_add_link_mode(cmd, advertising,
+							     Asym_Pause);
+			break;
+		default:
+			break;
+		}
+	} else {
+		cmd->base.autoneg = AUTONEG_DISABLE;
+	}
 
-	/* Set pause flow control settings */
+	/* Pause is always supported */
 	ethtool_link_ksettings_add_link_mode(cmd, supported, Pause);
 
-	switch (hw->fc.requested_mode) {
-	case igc_fc_full:
-		ethtool_link_ksettings_add_link_mode(cmd, advertising, Pause);
-		break;
-	case igc_fc_rx_pause:
-		ethtool_link_ksettings_add_link_mode(cmd, advertising, Pause);
-		ethtool_link_ksettings_add_link_mode(cmd, advertising,
-						     Asym_Pause);
-		break;
-	case igc_fc_tx_pause:
-		ethtool_link_ksettings_add_link_mode(cmd, advertising,
-						     Asym_Pause);
-		break;
-	default:
-		break;
-	}
-
 	status = pm_runtime_suspended(&adapter->pdev->dev) ?
 		 0 : rd32(IGC_STATUS);
 
@@ -1983,7 +1997,6 @@ static int igc_ethtool_get_link_ksettings(struct net_device *netdev,
 		cmd->base.duplex = DUPLEX_UNKNOWN;
 	}
 	cmd->base.speed = speed;
-	cmd->base.autoneg = AUTONEG_ENABLE;
 
 	/* MDI-X => 2; MDI =>1; Invalid =>0 */
 	if (hw->phy.media_type == igc_media_type_copper)
@@ -2000,6 +2013,41 @@ static int igc_ethtool_get_link_ksettings(struct net_device *netdev,
 	return 0;
 }
 
+/**
+ * igc_handle_autoneg_disabled - Configure forced speed/duplex settings
+ * @adapter: private driver structure
+ * @speed: requested speed (must be SPEED_10 or SPEED_100)
+ * @duplex: requested duplex
+ *
+ * Records forced speed/duplex when autoneg is disabled.
+ * Caller must validate speed before calling this function.
+ */
+static void igc_handle_autoneg_disabled(struct igc_adapter *adapter, u32 speed,
+					u8 duplex)
+{
+	struct igc_mac_info *mac = &adapter->hw.mac;
+
+	switch (speed) {
+	case SPEED_10:
+		mac->forced_speed_duplex = (duplex == DUPLEX_FULL) ?
+			IGC_FORCED_10F : IGC_FORCED_10H;
+		break;
+	case SPEED_100:
+		mac->forced_speed_duplex = (duplex == DUPLEX_FULL) ?
+			IGC_FORCED_100F : IGC_FORCED_100H;
+		break;
+	default:
+		WARN_ONCE(1, "Unsupported speed %u\n", speed);
+		return;
+	}
+
+	mac->autoneg_enabled = false;
+
+	/* Half-duplex cannot support flow control per IEEE 802.3 */
+	if (duplex != DUPLEX_FULL)
+		adapter->hw.fc.requested_mode = igc_fc_none;
+}
+
 /**
  * igc_handle_autoneg_enabled - Configure autonegotiation advertisement
  * @adapter: private driver structure
@@ -2038,6 +2086,7 @@ static void igc_handle_autoneg_enabled(struct igc_adapter *adapter,
 						  10baseT_Half))
 		advertised |= ADVERTISE_10_HALF;
 
+	hw->mac.autoneg_enabled = true;
 	hw->phy.autoneg_advertised = advertised;
 	if (adapter->fc_autoneg)
 		hw->fc.requested_mode = igc_fc_default;
@@ -2059,6 +2108,12 @@ igc_ethtool_set_link_ksettings(struct net_device *netdev,
 		return -EINVAL;
 	}
 
+	if (cmd->base.autoneg != AUTONEG_ENABLE &&
+	    cmd->base.autoneg != AUTONEG_DISABLE) {
+		netdev_info(dev, "Unsupported autoneg setting\n");
+		return -EINVAL;
+	}
+
 	/* MDI setting is only allowed when autoneg enabled because
 	 * some hardware doesn't allow MDI setting when speed or
 	 * duplex is forced.
@@ -2071,14 +2126,20 @@ igc_ethtool_set_link_ksettings(struct net_device *netdev,
 		}
 	}
 
+	if (cmd->base.autoneg == AUTONEG_DISABLE &&
+	    cmd->base.speed != SPEED_10 && cmd->base.speed != SPEED_100) {
+		netdev_info(dev, "Unsupported speed for forced link\n");
+		return -EINVAL;
+	}
+
 	while (test_and_set_bit(__IGC_RESETTING, &adapter->state))
 		usleep_range(1000, 2000);
 
-	if (cmd->base.autoneg == AUTONEG_ENABLE) {
+	if (cmd->base.autoneg == AUTONEG_ENABLE)
 		igc_handle_autoneg_enabled(adapter, cmd);
-	} else {
-		netdev_info(dev, "Force mode currently not supported\n");
-	}
+	else
+		igc_handle_autoneg_disabled(adapter, cmd->base.speed,
+					    cmd->base.duplex);
 
 	/* MDI-X => 2; MDI => 1; Auto => 3 */
 	if (cmd->base.eth_tp_mdix_ctrl) {
diff --git a/drivers/net/ethernet/intel/igc/igc_hw.h b/drivers/net/ethernet/intel/igc/igc_hw.h
index 86ab8f566f44..62aaee55668a 100644
--- a/drivers/net/ethernet/intel/igc/igc_hw.h
+++ b/drivers/net/ethernet/intel/igc/igc_hw.h
@@ -73,6 +73,13 @@ struct igc_info {
 
 extern const struct igc_info igc_base_info;
 
+enum igc_forced_speed_duplex {
+	IGC_FORCED_10H,
+	IGC_FORCED_10F,
+	IGC_FORCED_100H,
+	IGC_FORCED_100F,
+};
+
 struct igc_mac_info {
 	struct igc_mac_operations ops;
 
@@ -93,6 +100,8 @@ struct igc_mac_info {
 	bool arc_subsystem_valid;
 
 	bool get_link_status;
+	bool autoneg_enabled;
+	enum igc_forced_speed_duplex forced_speed_duplex;
 };
 
 struct igc_nvm_operations {
diff --git a/drivers/net/ethernet/intel/igc/igc_mac.c b/drivers/net/ethernet/intel/igc/igc_mac.c
index 142beb9ae557..8bbb6d5581c7 100644
--- a/drivers/net/ethernet/intel/igc/igc_mac.c
+++ b/drivers/net/ethernet/intel/igc/igc_mac.c
@@ -446,6 +446,16 @@ s32 igc_config_fc_after_link_up(struct igc_hw *hw)
 	u16 speed, duplex;
 	s32 ret_val = 0;
 
+	/* When autoneg is disabled, force the MAC flow control settings
+	 * to match the "fc" parameter.
+	 */
+	if (!hw->mac.autoneg_enabled) {
+		ret_val = igc_force_mac_fc(hw);
+		if (ret_val)
+			hw_dbg("Error forcing flow control settings\n");
+		goto out;
+	}
+
 	/* In auto-neg, we need to check and see if Auto-Neg has completed,
 	 * and if so, how the PHY and link partner has flow control
 	 * configured.
diff --git a/drivers/net/ethernet/intel/igc/igc_main.c b/drivers/net/ethernet/intel/igc/igc_main.c
index 72bc5128d8b8..437e1d1ef1e4 100644
--- a/drivers/net/ethernet/intel/igc/igc_main.c
+++ b/drivers/net/ethernet/intel/igc/igc_main.c
@@ -7298,7 +7298,7 @@ static int igc_probe(struct pci_dev *pdev,
 	/* Initialize link properties that are user-changeable */
 	adapter->fc_autoneg = true;
 	hw->phy.autoneg_advertised = 0xaf;
-
+	hw->mac.autoneg_enabled = true;
 	hw->fc.requested_mode = igc_fc_default;
 	hw->fc.current_mode = igc_fc_default;
 
diff --git a/drivers/net/ethernet/intel/igc/igc_phy.c b/drivers/net/ethernet/intel/igc/igc_phy.c
index 6c4d204aecfa..4cf737fb3b21 100644
--- a/drivers/net/ethernet/intel/igc/igc_phy.c
+++ b/drivers/net/ethernet/intel/igc/igc_phy.c
@@ -494,12 +494,20 @@ s32 igc_setup_copper_link(struct igc_hw *hw)
 	s32 ret_val = 0;
 	bool link;
 
-	/* Setup autoneg and flow control advertisement and perform
-	 * autonegotiation.
-	 */
-	ret_val = igc_copper_link_autoneg(hw);
-	if (ret_val)
-		goto out;
+	if (hw->mac.autoneg_enabled) {
+		/* Setup autoneg and flow control advertisement and perform
+		 * autonegotiation.
+		 */
+		ret_val = igc_copper_link_autoneg(hw);
+		if (ret_val)
+			goto out;
+	} else {
+		ret_val = hw->phy.ops.force_speed_duplex(hw);
+		if (ret_val) {
+			hw_dbg("Error Forcing Speed/Duplex\n");
+			goto out;
+		}
+	}
 
 	/* Check link status. Wait up to 100 microseconds for link to become
 	 * valid.
@@ -778,3 +786,48 @@ u16 igc_read_phy_fw_version(struct igc_hw *hw)
 
 	return gphy_version;
 }
+
+/**
+ * igc_force_speed_duplex - Force PHY speed and duplex settings
+ * @hw: pointer to the HW structure
+ *
+ * Programs the GPY PHY control register to disable autonegotiation
+ * and force the speed/duplex indicated by hw->mac.forced_speed_duplex.
+ */
+s32 igc_force_speed_duplex(struct igc_hw *hw)
+{
+	struct igc_phy_info *phy = &hw->phy;
+	u16 phy_ctrl;
+	s32 ret_val;
+
+	ret_val = phy->ops.read_reg(hw, PHY_CONTROL, &phy_ctrl);
+	if (ret_val)
+		return ret_val;
+
+	phy_ctrl &= ~(MII_CR_SPEED_MASK | MII_CR_DUPLEX_EN |
+		      MII_CR_AUTO_NEG_EN | MII_CR_RESTART_AUTO_NEG);
+
+	switch (hw->mac.forced_speed_duplex) {
+	case IGC_FORCED_10H:
+		phy_ctrl |= MII_CR_SPEED_10;
+		break;
+	case IGC_FORCED_10F:
+		phy_ctrl |= MII_CR_SPEED_10 | MII_CR_DUPLEX_EN;
+		break;
+	case IGC_FORCED_100H:
+		phy_ctrl |= MII_CR_SPEED_100;
+		break;
+	case IGC_FORCED_100F:
+		phy_ctrl |= MII_CR_SPEED_100 | MII_CR_DUPLEX_EN;
+		break;
+	default:
+		return -IGC_ERR_CONFIG;
+	}
+
+	ret_val = phy->ops.write_reg(hw, PHY_CONTROL, phy_ctrl);
+	if (ret_val)
+		return ret_val;
+
+	hw->mac.get_link_status = true;
+	return 0;
+}
diff --git a/drivers/net/ethernet/intel/igc/igc_phy.h b/drivers/net/ethernet/intel/igc/igc_phy.h
index 832a7e359f18..d37a89174826 100644
--- a/drivers/net/ethernet/intel/igc/igc_phy.h
+++ b/drivers/net/ethernet/intel/igc/igc_phy.h
@@ -18,5 +18,6 @@ void igc_power_down_phy_copper(struct igc_hw *hw);
 s32 igc_write_phy_reg_gpy(struct igc_hw *hw, u32 offset, u16 data);
 s32 igc_read_phy_reg_gpy(struct igc_hw *hw, u32 offset, u16 *data);
 u16 igc_read_phy_fw_version(struct igc_hw *hw);
+s32 igc_force_speed_duplex(struct igc_hw *hw);
 
 #endif
-- 
2.43.0