From: "Mike Marciniszyn (Meta)" <mike.marciniszyn@gmail.com>

Consolidate the register reads for boiler plate registers
to reduce LOC and cleanup pcs reads for DEVS1 to
fetch overrides for reserved bits that the hardware does not
return.

Signed-off-by: Mike Marciniszyn (Meta) <mike.marciniszyn@gmail.com>
---
v2:
  - Restore pcs register read for DEVS2
  - read pcs DEVS1 overrides and or into return
v1: https://lore.kernel.org/all/20260428172810.175077-4-mike.marciniszyn@gmail.com/

 drivers/net/ethernet/meta/fbnic/fbnic_mdio.c | 64 ++++++++++++--------
 1 file changed, 40 insertions(+), 24 deletions(-)

diff --git a/drivers/net/ethernet/meta/fbnic/fbnic_mdio.c b/drivers/net/ethernet/meta/fbnic/fbnic_mdio.c
index 709041f7fc43..a3a072597a2c 100644
--- a/drivers/net/ethernet/meta/fbnic/fbnic_mdio.c
+++ b/drivers/net/ethernet/meta/fbnic/fbnic_mdio.c
@@ -11,6 +11,26 @@
 #define FBNIC_PCS_VENDOR	BIT(9)
 #define FBNIC_PCS_ZERO_MASK	(DW_VENDOR - FBNIC_PCS_VENDOR)

+static int
+fbnic_mdio_ids(int id, int regnum)
+{
+	/* return correct IDs */
+	switch (regnum) {
+	case MDIO_DEVID1:
+		return id >> 16;
+	case MDIO_DEVID2:
+		return id & 0xffff;
+	case MDIO_DEVS1:
+		return MDIO_DEVS_SEP_PMA1 | MDIO_DEVS_PMAPMD | MDIO_DEVS_PCS;
+	case MDIO_DEVS2:
+		return 0;
+	case MDIO_STAT2:
+		return MDIO_STAT2_DEVPRST_VAL;
+	}
+
+	return 0;
+}
+
 static int
 fbnic_mdio_read_pmd(struct fbnic_dev *fbd, int addr, int regnum)
 {
@@ -29,18 +49,6 @@ fbnic_mdio_read_pmd(struct fbnic_dev *fbd, int addr, int regnum)
 	}

 	switch (regnum) {
-	case MDIO_DEVID1:
-		ret = MP_FBNIC_XPCS_PMA_100G_ID >> 16;
-		break;
-	case MDIO_DEVID2:
-		ret = MP_FBNIC_XPCS_PMA_100G_ID & 0xffff;
-		break;
-	case MDIO_DEVS1:
-		ret = MDIO_DEVS_PMAPMD | MDIO_DEVS_PCS;
-		break;
-	case MDIO_STAT2:
-		ret = MDIO_STAT2_DEVPRST_VAL;
-		break;
 	case MDIO_PMA_RXDET:
 		/* If training isn't complete default to 0 */
 		if (fbd->pmd_state != FBNIC_PMD_SEND_DATA)
@@ -51,6 +59,7 @@ fbnic_mdio_read_pmd(struct fbnic_dev *fbd, int addr, int regnum)
 		       (MDIO_PMD_RXDET_1 / FBNIC_AUI_MODE_R2));
 		break;
 	default:
+		ret = fbnic_mdio_ids(MP_FBNIC_XPCS_PMA_100G_ID, regnum);
 		break;
 	}

@@ -64,7 +73,7 @@ fbnic_mdio_read_pmd(struct fbnic_dev *fbd, int addr, int regnum)
 static int
 fbnic_mdio_read_pcs(struct fbnic_dev *fbd, int addr, int regnum)
 {
-	int ret, offset = 0;
+	int ret, offset = 0, overrides = 0;

 	/* We will need access to both PCS instances to get config info */
 	if (addr >= 2)
@@ -75,18 +84,25 @@ fbnic_mdio_read_pcs(struct fbnic_dev *fbd, int addr, int regnum)
 		return 0;

 	/* Intercept and return correct ID for PCS */
-	if (regnum == MDIO_DEVID1)
-		return DW_XPCS_ID >> 16;
-	if (regnum == MDIO_DEVID2)
-		return DW_XPCS_ID & 0xffff;
-	if (regnum == MDIO_DEVS1)
-		return MDIO_DEVS_PMAPMD | MDIO_DEVS_PCS;
-
-	/* Swap vendor page bit for FBNIC PCS vendor page bit */
-	if (regnum & DW_VENDOR)
-		offset ^= DW_VENDOR | FBNIC_PCS_VENDOR;
+	switch (regnum) {
+	case MDIO_DEVID1 ... MDIO_DEVID2:
+		ret = fbnic_mdio_ids(DW_XPCS_ID, regnum);
+		break;
+	case MDIO_DEVS1:
+		/* DW IP returns MDIO_DEVS_SEP_PMA1, MDIO_DEVS_PMAPMD,
+		 * and MDIO_DEVS_PCS as 0
+		 */
+		overrides = fbnic_mdio_ids(DW_XPCS_ID, regnum);
+		fallthrough;
+	default:
+		/* Swap vendor page bit for FBNIC PCS vendor page bit */
+		if (regnum & DW_VENDOR)
+			offset ^= DW_VENDOR | FBNIC_PCS_VENDOR;

-	ret = fbnic_rd32(fbd, FBNIC_PCS_PAGE(addr) + (regnum ^ offset));
+		ret = fbnic_rd32(fbd, FBNIC_PCS_PAGE(addr) + (regnum ^ offset));
+		ret |= overrides;
+		break;
+	}

 	dev_dbg(fbd->dev,
 		"SWMII PCS Rd: Addr: %d RegNum: %d Value: 0x%04x\n",
--
2.43.0