kernel: rework Huawei-compatible OEM SFP GE-T

This patch was added in 09b086eecaa545cf7f30bc7e394a32751e25db65
("kernel: add quirk for Huawei-compatible OEM SFP GE-T"). Add patch
title, description and SoB to follow OpenWrt's developer guide for
working patches to prepare it for being sent upstream. This patch
should be discussed with Russell King and merged to Linux kernel.

Co-authored-by: Josef Schlehofer <[email protected]>
Signed-off-by: Daniel Golle <[email protected]>

target/linux/generic/hack-5.15/790-SFP-GE-T-ignore-TX_FAULT.patch

@@ -1,36 +1,54 @@
+From 7cc39a6bedbd85f3ff7e16845f310e4ce8d9833f Mon Sep 17 00:00:00 2001
+From: Daniel Golle <[email protected]>
+Date: Tue, 6 Sep 2022 00:31:19 +0100
+Subject: [PATCH] net: sfp: add quirk for ATS SFP-GE-T 1000Base-TX module
+To: [email protected],
+    [email protected],
+    Russell King <[email protected]>,
+    Andrew Lunn <[email protected]>,
+    Heiner Kallweit <[email protected]>
+Cc: David S. Miller <[email protected]>,
+    Eric Dumazet <[email protected]>,
+    Jakub Kicinski <[email protected]>,
+    Paolo Abeni <[email protected]>,
+    Josef Schlehofer <[email protected]>
+
+This copper module comes with broken TX_FAULT indicator which must be
+ignored for it to work. Implement ignoring TX_FAULT state bit also
+during reset/insertion and mute the warning telling the user that the
+module indicates TX_FAULT.
+
+Co-authored-by: Josef Schlehofer <[email protected]>
+Signed-off-by: Daniel Golle <[email protected]>
+---
+ drivers/net/phy/sfp.c | 14 +++++++++++---
+ 1 file changed, 11 insertions(+), 3 deletions(-)
+
 --- a/drivers/net/phy/sfp.c
 +++ b/drivers/net/phy/sfp.c
-@@ -1803,6 +1803,7 @@ static int sfp_sm_mod_probe(struct sfp *
- 	struct sfp_eeprom_id id;
- 	bool cotsworks_sfbg;
- 	bool cotsworks;
-+	bool oem_ge_t;
- 	u8 check;
- 	int ret;
- 
-@@ -1851,6 +1852,10 @@ static int sfp_sm_mod_probe(struct sfp *
- 		}
- 	}
- 
-+	/* Some cheap SFP-GE-T modules always indicate TX fault */
-+	oem_ge_t = !memcmp(id.base.vendor_name, "OEM             ", 16) &&
-+		   !memcmp(id.base.vendor_pn, "SFP-GE-T    ", 12);
-+
- 	/* Cotsworks do not seem to update the checksums when they
- 	 * do the final programming with the final module part number,
- 	 * serial number and date code.
-@@ -1946,8 +1951,8 @@ static int sfp_sm_mod_probe(struct sfp *
- 	else
- 		sfp->module_t_start_up = T_START_UP;
- 
--	if (!memcmp(id.base.vendor_name, "HUAWEI          ", 16) &&
--	    !memcmp(id.base.vendor_pn, "MA5671A         ", 16))
-+	if ((!memcmp(id.base.vendor_name, "HUAWEI          ", 16) &&
-+	    !memcmp(id.base.vendor_pn, "MA5671A         ", 16)) || oem_ge_t)
- 		sfp->tx_fault_ignore = true;
- 	else
- 		sfp->tx_fault_ignore = false;
-@@ -2404,10 +2409,12 @@ static void sfp_check_state(struct sfp *
+@@ -369,6 +369,11 @@ static const struct sfp_quirk sfp_quirks
+ 		.modes = sfp_quirk_2500basex,
+ 		.fixup = sfp_fixup_ignore_tx_fault,
+ 	}, {
++		// OEM SFP-GE-T is 1000Base-T module
++		.vendor = "OEM",
++		.part = "SFP-GE-T",
++		.fixup = sfp_fixup_ignore_tx_fault,
++	}, {
+ 		// Lantech 8330-262D-E can operate at 2500base-X, but
+ 		// incorrectly report 2500MBd NRZ in their EEPROM
+ 		.vendor = "Lantech",
+@@ -2303,7 +2308,8 @@ static void sfp_sm_main(struct sfp *sfp,
+ 			 * or t_start_up, so assume there is a fault.
+ 			 */
+ 			sfp_sm_fault(sfp, SFP_S_INIT_TX_FAULT,
+-				     sfp->sm_fault_retries == N_FAULT_INIT);
++				     !sfp->tx_fault_ignore &&
++				     (sfp->sm_fault_retries == N_FAULT_INIT));
+ 		} else if (event == SFP_E_TIMEOUT || event == SFP_E_TX_CLEAR) {
+ 	init_done:
+ 			sfp->sm_phy_retries = R_PHY_RETRY;
+@@ -2526,10 +2532,12 @@ static void sfp_check_state(struct sfp *
  	mutex_lock(&sfp->st_mutex);
  	state = sfp_get_state(sfp);
  	changed = state ^ sfp->state;