[Intel-wired-lan] [PATCH iwl-next v1 1/3] igc: prepare for RSS key get/set support

[Loktionov, Aleksandr]

> -----Original Message-----
> From: Intel-wired-lan <intel-wired-lan-bounces at osuosl.org> On Behalf
> Of Kohei Enju
> Sent: Saturday, October 25, 2025 5:02 PM
> To: intel-wired-lan at lists.osuosl.org; netdev at vger.kernel.org
> Cc: Nguyen, Anthony L <anthony.l.nguyen at intel.com>; Kitszel,
> Przemyslaw <przemyslaw.kitszel at intel.com>; Andrew Lunn
> <andrew+netdev at lunn.ch>; David S. Miller <davem at davemloft.net>; Eric
> Dumazet <edumazet at google.com>; Jakub Kicinski <kuba at kernel.org>; Paolo
> Abeni <pabeni at redhat.com>; kohei.enju at gmail.com; Kohei Enju
> <enjuk at amazon.com>
> Subject: [Intel-wired-lan] [PATCH iwl-next v1 1/3] igc: prepare for
> RSS key get/set support
> 
> Store the RSS key inside struct igc_adapter and introduce the
> igc_write_rss_key() helper function. This allows the driver to program
> the RSSRK registers using a persistent RSS key, instead of using a
> stack-local buffer in igc_setup_mrqc().
> 
> This is a preparation patch for adding RSS key get/set support in
> subsequent changes, and no functional change is intended in this
> patch.
> 
> Signed-off-by: Kohei Enju <enjuk at amazon.com>
> ---
>  drivers/net/ethernet/intel/igc/igc.h         |  3 +++
>  drivers/net/ethernet/intel/igc/igc_ethtool.c | 12 ++++++++++++
>  drivers/net/ethernet/intel/igc/igc_main.c    |  6 ++----
>  3 files changed, 17 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/net/ethernet/intel/igc/igc.h
> b/drivers/net/ethernet/intel/igc/igc.h
> index a427f05814c1..dd159397d191 100644
> --- a/drivers/net/ethernet/intel/igc/igc.h
> +++ b/drivers/net/ethernet/intel/igc/igc.h
> @@ -30,6 +30,7 @@ void igc_ethtool_set_ops(struct net_device *);
> 
>  #define MAX_ETYPE_FILTER		8
>  #define IGC_RETA_SIZE			128
> +#define IGC_RSS_KEY_SIZE		40
> 
>  /* SDP support */
>  #define IGC_N_EXTTS	2
> @@ -302,6 +303,7 @@ struct igc_adapter {
>  	unsigned int nfc_rule_count;
> 
>  	u8 rss_indir_tbl[IGC_RETA_SIZE];
> +	u8 rss_key[IGC_RSS_KEY_SIZE];
> 
>  	unsigned long link_check_timeout;
>  	struct igc_info ei;
> @@ -360,6 +362,7 @@ unsigned int igc_get_max_rss_queues(struct
> igc_adapter *adapter);  void igc_set_flag_queue_pairs(struct
> igc_adapter *adapter,
>  			      const u32 max_rss_queues);
>  int igc_reinit_queues(struct igc_adapter *adapter);
> +void igc_write_rss_key(struct igc_adapter *adapter);
>  void igc_write_rss_indir_tbl(struct igc_adapter *adapter);  bool
> igc_has_link(struct igc_adapter *adapter);  void igc_reset(struct
> igc_adapter *adapter); diff --git
> a/drivers/net/ethernet/intel/igc/igc_ethtool.c
> b/drivers/net/ethernet/intel/igc/igc_ethtool.c
> index ca93629b1d3a..f89c2cbaace0 100644
> --- a/drivers/net/ethernet/intel/igc/igc_ethtool.c
> +++ b/drivers/net/ethernet/intel/igc/igc_ethtool.c
> @@ -1456,6 +1456,18 @@ static int igc_ethtool_set_rxnfc(struct
> net_device *dev,
>  	}
>  }
> 
> +void igc_write_rss_key(struct igc_adapter *adapter) {
> +	struct igc_hw *hw = &adapter->hw;
> +	u32 val;
> +	int i;
> +
> +	for (i = 0; i < IGC_RSS_KEY_SIZE / 4; i++) {
> +		val = get_unaligned_le32(&adapter->rss_key[i * 4]);
> +		wr32(IGC_RSSRK(i), val);
> +	}
> +}
> +
>  void igc_write_rss_indir_tbl(struct igc_adapter *adapter)  {
>  	struct igc_hw *hw = &adapter->hw;
> diff --git a/drivers/net/ethernet/intel/igc/igc_main.c
> b/drivers/net/ethernet/intel/igc/igc_main.c
> index 728d7ca5338b..1f0a601cbcef 100644
> --- a/drivers/net/ethernet/intel/igc/igc_main.c
> +++ b/drivers/net/ethernet/intel/igc/igc_main.c
> @@ -778,11 +778,9 @@ static void igc_setup_mrqc(struct igc_adapter
> *adapter)
>  	struct igc_hw *hw = &adapter->hw;
>  	u32 j, num_rx_queues;
>  	u32 mrqc, rxcsum;
> -	u32 rss_key[10];
> 
> -	netdev_rss_key_fill(rss_key, sizeof(rss_key));
> -	for (j = 0; j < 10; j++)
> -		wr32(IGC_RSSRK(j), rss_key[j]);
> +	netdev_rss_key_fill(adapter->rss_key, sizeof(adapter-
> >rss_key));
> +	igc_write_rss_key(adapter);
> 
>  	num_rx_queues = adapter->rss_queues;
> 
> --
> 2.51.0

Reviewed-by: Aleksandr Loktionov <aleksandr.loktionov at intel.com>