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* [PATCH net] amd-xgbe: fix MAC_TCR_SS register width for 2.5G and 10M speeds
@ 2026-02-26 17:07 Raju Rangoju
  2026-02-28 22:30 ` patchwork-bot+netdevbpf
  0 siblings, 1 reply; 2+ messages in thread
From: Raju Rangoju @ 2026-02-26 17:07 UTC (permalink / raw)
  To: netdev
  Cc: linux-kernel, pabeni, kuba, edumazet, davem, andrew+netdev,
	Raju.Rangoju, Guruvendra Punugupati

Extend the MAC_TCR_SS (Speed Select) register field width from 2 bits
to 3 bits to properly support all speed settings.

The MAC_TCR register's SS field encoding requires 3 bits to represent
all supported speeds:
  - 0x00: 10Gbps (XGMII)
  - 0x02: 2.5Gbps (GMII) / 100Mbps
  - 0x03: 1Gbps / 10Mbps
  - 0x06: 2.5Gbps (XGMII) - P100a only

With only 2 bits, values 0x04-0x07 cannot be represented, which breaks
2.5G XGMII mode on newer platforms and causes incorrect speed select
values to be programmed.

Fixes: 07445f3c7ca1 ("amd-xgbe: Add support for 10 Mbps speed")
Co-developed-by: Guruvendra Punugupati <Guruvendra.Punugupati@amd.com>
Signed-off-by: Guruvendra Punugupati <Guruvendra.Punugupati@amd.com>
Signed-off-by: Raju Rangoju <Raju.Rangoju@amd.com>
---
 drivers/net/ethernet/amd/xgbe/xgbe-common.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/amd/xgbe/xgbe-common.h b/drivers/net/ethernet/amd/xgbe/xgbe-common.h
index 711f295eb777..80c2c27ac9dc 100644
--- a/drivers/net/ethernet/amd/xgbe/xgbe-common.h
+++ b/drivers/net/ethernet/amd/xgbe/xgbe-common.h
@@ -431,7 +431,7 @@
 #define MAC_SSIR_SSINC_INDEX		16
 #define MAC_SSIR_SSINC_WIDTH		8
 #define MAC_TCR_SS_INDEX		29
-#define MAC_TCR_SS_WIDTH		2
+#define MAC_TCR_SS_WIDTH		3
 #define MAC_TCR_TE_INDEX		0
 #define MAC_TCR_TE_WIDTH		1
 #define MAC_TCR_VNE_INDEX		24
-- 
2.34.1


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2026-02-26 17:07 [PATCH net] amd-xgbe: fix MAC_TCR_SS register width for 2.5G and 10M speeds Raju Rangoju
2026-02-28 22:30 ` patchwork-bot+netdevbpf

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