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From:   Rodrigo Cataldo via B4 Relay 
        <devnull+rodrigo.cadore.l-acoustics.com@kernel.org>
Date:   Fri, 08 Dec 2023 15:58:16 +0100
Subject: [PATCH iwl-net] igc: Fix hicredit calculation
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Message-Id: <20231208-igc-fix-hicredit-calc-v1-1-7e505fbe249d@l-acoustics.com>
To:     Jesse Brandeburg <jesse.brandeburg@intel.com>,
        Tony Nguyen <anthony.l.nguyen@intel.com>,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        Aravindhan Gunasekaran <aravindhan.gunasekaran@intel.com>,
        Mallikarjuna Chilakala <mallikarjuna.chilakala@intel.com>,
        Vinicius Costa Gomes <vinicius.gomes@intel.com>
Cc:     intel-wired-lan@lists.osuosl.org, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org, Kurt Kanzenbach <kurt@linutronix.de>,
        Rodrigo Cataldo <rodrigo.cadore@l-acoustics.com>
Reply-To: <rodrigo.cadore@l-acoustics.com>
Precedence: bulk

From: Rodrigo Cataldo <rodrigo.cadore@l-acoustics.com>

According to the Intel Software Manual for I225, Section 7.5.2.7,
hicredit should be multiplied by the constant link-rate value, 0x7736.

Currently, the old constant link-rate value, 0x7735, from the boards
supported on igb are being used, most likely due to a copy'n'paste, as
the rest of the logic is the same for both drivers.

Update hicredit accordingly.

Fixes: 1ab011b0bf07 ("igc: Add support for CBS offloading")
Reviewed-by: Kurt Kanzenbach <kurt@linutronix.de>
Signed-off-by: Rodrigo Cataldo <rodrigo.cadore@l-acoustics.com>
---
This is a simple fix for the credit calculation on igc devices
(i225/i226) to match the Intel software manual.

This is my first contribution to the Linux Kernel. Apologies for any
mistakes and let me know if I improve anything.
---
 drivers/net/ethernet/intel/igc/igc_tsn.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/intel/igc/igc_tsn.c b/drivers/net/ethernet/intel/igc/igc_tsn.c
index a9c08321aca9..22cefb1eeedf 100644
--- a/drivers/net/ethernet/intel/igc/igc_tsn.c
+++ b/drivers/net/ethernet/intel/igc/igc_tsn.c
@@ -227,7 +227,7 @@ static int igc_tsn_enable_offload(struct igc_adapter *adapter)
 			wr32(IGC_TQAVCC(i), tqavcc);
 
 			wr32(IGC_TQAVHC(i),
-			     0x80000000 + ring->hicredit * 0x7735);
+			     0x80000000 + ring->hicredit * 0x7736);
 		} else {
 			/* Disable any CBS for the queue */
 			txqctl &= ~(IGC_TXQCTL_QAV_SEL_MASK);

---
base-commit: 2078a341f5f609d55667c2dc6337f90d8f322b8f
change-id: 20231206-igc-fix-hicredit-calc-028bf73c50a8

Best regards,
-- 
Rodrigo Cataldo <rodrigo.cadore@l-acoustics.com>