[PATCH net-next v3 0/2] net: sfp: quirk support for XGS-PON ONT sticks with unclean EEPROMs

[PATCH net-next v3 0/2] net: sfp: quirk support for XGS-PON ONT sticks with unclean EEPROMs

[Martino Dell'Ambrogio]

Some clone XGS-PON ONT sticks return EEPROM reads where the vendor PN
field contains non-printable garbage past the legitimate string instead
of the SFF-8472 mandated space padding. sfp_strlen() then can't trim
the field, the exact-length check in sfp_match() rejects the quirk
entry before the string comparison runs, and the quirk silently never
applies - so the kernel honors the module's spurious TX_FAULT and
eventually disables it.

Patch 1 adds an opt-in part-prefix-matching flag to the quirk table so
such modules can still be matched; the vendor name is always matched
exactly and existing entries behave as before. Patch 2 adds two ONT
stick entries wired to the existing potron fixup: the "OEM"
XGSPONST2001, which needs the prefix matching (it returns trailing
garbage in the PN field on cold power-up reads), and the Fiberstore
XGS-SFP-ONT-MACI, whose PN field is fully occupied by the truncated
product name and matches exactly.

Both quirks are in production use on a Bananapi BPI-R4 (MT7988A)
router on an XGS-PON uplink, backported onto 6.12.

v3, addressing Jakub's review [1][2]:
 - prefix matching is now scoped to the part field only; the vendor
   name comparison is always exact
 - the FS XGS-SFP-ONT-MACI entry is back to plain SFP_QUIRK_F: its PN
   field carries the full 16-character truncated product name, so
   prefix matching bought it nothing
 - commit messages reworded accordingly; patch 1 now describes the
   mechanism only
 - dropped the Reviewed-by tags given the functional changes

[1] https://lore.kernel.org/netdev/20260811001427.1036657-1-kuba@kernel.org/
[2] https://lore.kernel.org/netdev/20260811001429.1036686-1-kuba@kernel.org/

v2 (repost + checkpatch fix): https://lore.kernel.org/netdev/20260806074308.1996917-1-tillo@tillo.ch/
v1: https://lore.kernel.org/netdev/20260705185440.136496-1-tillo@tillo.ch/

Martino Dell'Ambrogio (2):
  net: sfp: allow prefix matching in quirk lookup
  net: sfp: add quirks for OEM XGSPONST2001 and FS XGS-SFP-ONT-MACI

 drivers/net/phy/sfp.c | 38 +++++++++++++++++++++++++++++++++-----
 drivers/net/phy/sfp.h |  1 +
 2 files changed, 34 insertions(+), 5 deletions(-)


base-commit: ac155a26750a595703e7dadff84735456d75a479
-- 
2.47.3

[PATCH net-next v3 1/2] net: sfp: allow prefix matching in quirk lookup

[Martino Dell'Ambrogio]

Some clone SFP modules return EEPROM reads where the vendor PN field
contains non-printable garbage past the trailing legitimate characters
instead of the SFF-8472 mandated space padding. The current sfp_match()
requires an exact full-field length match: sfp_strlen() returns 16 (no
trailing spaces or NULs to strip), but strlen() of the quirk string is
shorter, so the length comparison rejects the entry before strncmp() is
even called and the quirk silently never applies.

Add a part_prefix_match flag to struct sfp_quirk and a
SFP_QUIRK_F_PREFIX macro. When set, sfp_match() compares only strlen()
leading bytes of the quirk part string, ignoring trailing field bytes.
The vendor name comparison always stays exact. Existing exact-match
quirks are unaffected (part_prefix_match defaults to false via zero-init
in the existing SFP_QUIRK macros).

This patch only adds the mechanism; the first user is added by the
following patch.

Signed-off-by: Martino Dell'Ambrogio <tillo@tillo.ch>
---
 drivers/net/phy/sfp.c | 23 ++++++++++++++++++-----
 drivers/net/phy/sfp.h |  1 +
 2 files changed, 19 insertions(+), 5 deletions(-)

diff --git a/drivers/net/phy/sfp.c b/drivers/net/phy/sfp.c
index 508b6cc8e..15033cbf7 100644
--- a/drivers/net/phy/sfp.c
+++ b/drivers/net/phy/sfp.c
@@ -516,6 +516,15 @@ static void sfp_quirk_ubnt_uf_instant(const struct sfp_eeprom_id *id,
 	{ .vendor = _v, .part = _p, .support = _s, .fixup = _f, }
 #define SFP_QUIRK_S(_v, _p, _s) SFP_QUIRK(_v, _p, _s, NULL)
 #define SFP_QUIRK_F(_v, _p, _f) SFP_QUIRK(_v, _p, NULL, _f)
+/* Like SFP_QUIRK_F, but matches the part as a prefix; the vendor name
+ * is still matched exactly. Use for modules whose EEPROM vendor PN
+ * field reads back with garbage past the legitimate characters instead
+ * of the SFF-8472-mandated space padding, so sfp_strlen can't trim the
+ * field down to the legitimate length.
+ */
+#define SFP_QUIRK_F_PREFIX(_v, _p, _f) \
+	{ .vendor = _v, .part = _p, .support = NULL, .fixup = _f, \
+	  .part_prefix_match = true }
 
 static const struct sfp_quirk sfp_quirks[] = {
 	// Alcatel Lucent G-010S-P can operate at 2500base-X, but incorrectly
@@ -629,13 +638,16 @@ static size_t sfp_strlen(const char *str, size_t maxlen)
 	return size;
 }
 
-static bool sfp_match(const char *qs, const char *str, size_t len)
+static bool sfp_match(const char *qs, const char *str, size_t len, bool prefix)
 {
+	size_t qs_len;
+
 	if (!qs)
 		return true;
-	if (strlen(qs) != len)
+	qs_len = strlen(qs);
+	if (prefix ? qs_len > len : qs_len != len)
 		return false;
-	return !strncmp(qs, str, len);
+	return !strncmp(qs, str, qs_len);
 }
 
 static const struct sfp_quirk *sfp_lookup_quirk(const struct sfp_eeprom_id *id)
@@ -648,8 +660,9 @@ static const struct sfp_quirk *sfp_lookup_quirk(const struct sfp_eeprom_id *id)
 	ps = sfp_strlen(id->base.vendor_pn, ARRAY_SIZE(id->base.vendor_pn));
 
 	for (i = 0, q = sfp_quirks; i < ARRAY_SIZE(sfp_quirks); i++, q++)
-		if (sfp_match(q->vendor, id->base.vendor_name, vs) &&
-		    sfp_match(q->part, id->base.vendor_pn, ps))
+		if (sfp_match(q->vendor, id->base.vendor_name, vs, false) &&
+		    sfp_match(q->part, id->base.vendor_pn, ps,
+			      q->part_prefix_match))
 			return q;
 
 	return NULL;
diff --git a/drivers/net/phy/sfp.h b/drivers/net/phy/sfp.h
index 879dff7af..19fe29d84 100644
--- a/drivers/net/phy/sfp.h
+++ b/drivers/net/phy/sfp.h
@@ -12,6 +12,7 @@ struct sfp_quirk {
 	void (*support)(const struct sfp_eeprom_id *id,
 			struct sfp_module_caps *caps);
 	void (*fixup)(struct sfp *sfp);
+	bool part_prefix_match;
 };
 
 struct sfp_socket_ops {
-- 
2.47.3

[PATCH net-next v3 2/2] net: sfp: add quirks for OEM XGSPONST2001 and FS XGS-SFP-ONT-MACI

[Martino Dell'Ambrogio]

Cheap XGS-PON ONT sticks identifying as vendor "OEM", PN "XGSPONST2001"
have broken TX_FAULT and LOS indicators (driven by the ONU serial
passthrough wires) and need a longer T_START_UP than the SFF-8472
default. The Fiberstore XGS-SFP-ONT-MACI MAC-mode ONT stick has the
same ONT-class TX_FAULT/LOS wiring and startup behaviour. Apply the
existing sfp_fixup_potron handler to both, which masks both signals
and bumps T_START_UP to T_START_UP_BAD_GPON.

The XGSPONST2001 returns the 12 legitimate PN characters followed by
non-printable garbage on cold power-up reads (the same module reads
back clean and space-padded after a warm reseat), which defeats
exact-length matching precisely on the boot where the quirk must
apply: the kernel honors the spurious TX_FAULT and the SFP state
machine eventually disables the module. Match its part as a prefix
using SFP_QUIRK_F_PREFIX.

The XGS-SFP-ONT-MACI PN is the product name (XGS-SFP-ONT-MAC-I)
truncated at the 16-byte field width, so the field is fully occupied
by legitimate characters and a plain exact-match SFP_QUIRK_F entry is
correct.

Signed-off-by: Martino Dell'Ambrogio <tillo@tillo.ch>
---
 drivers/net/phy/sfp.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/drivers/net/phy/sfp.c b/drivers/net/phy/sfp.c
index 15033cbf7..2ec91466a 100644
--- a/drivers/net/phy/sfp.c
+++ b/drivers/net/phy/sfp.c
@@ -557,6 +557,13 @@ static const struct sfp_quirk sfp_quirks[] = {
 	SFP_QUIRK("FS", "GPON-ONU-34-20BI", sfp_quirk_2500basex,
 		  sfp_fixup_ignore_tx_fault),
 
+	// Fiberstore XGS-SFP-ONT-MACI is a MAC-mode XGS-PON ONT stick with
+	// ONT-class serial-passthrough TX_FAULT/LOS wiring and slow startup;
+	// mask both signals and extend T_START_UP via the potron fixup. The
+	// PN is the product name (XGS-SFP-ONT-MAC-I) truncated at the 16-byte
+	// field width, so the field is fully occupied and matches exactly.
+	SFP_QUIRK_F("FS", "XGS-SFP-ONT-MACI", sfp_fixup_potron),
+
 	SFP_QUIRK_F("HALNy", "HL-GSFP", sfp_fixup_halny_gsfp),
 
 	SFP_QUIRK_F("H-COM", "SPP425H-GAB4", sfp_fixup_potron),
@@ -617,6 +624,14 @@ static const struct sfp_quirk sfp_quirks[] = {
 	SFP_QUIRK_S("OEM", "SFP-2.5G-LH20-A", sfp_quirk_2500basex),
 	SFP_QUIRK_F("OEM", "RTSFP-10", sfp_fixup_rollball_cc),
 	SFP_QUIRK_F("OEM", "RTSFP-10G", sfp_fixup_rollball_cc),
+
+	// OEM XGSPONST2001 is an XGS-PON ONT stick with broken TX_FAULT and
+	// LOS indicators and slow startup, just like potron. On cold
+	// power-up the EEPROM vendor PN field reads back with non-printable
+	// garbage past the legitimate string instead of space padding, so
+	// match the part as a prefix.
+	SFP_QUIRK_F_PREFIX("OEM", "XGSPONST2001", sfp_fixup_potron),
+
 	SFP_QUIRK_F("Turris", "RTSFP-2.5G", sfp_fixup_rollball),
 	SFP_QUIRK_F("Turris", "RTSFP-10", sfp_fixup_rollball),
 	SFP_QUIRK_F("Turris", "RTSFP-10G", sfp_fixup_rollball),
-- 
2.47.3