diff mbox series

[net-next,v4,1/4] net: phy: Introduce QUSGMII PHY mode

Message ID 20220801073713.32290-2-maxime.chevallier@bootlin.com (mailing list archive)
State Deferred
Delegated to: Netdev Maintainers
Headers show
Series net: Introduce QUSGMII phy mode | expand

Checks

Context Check Description
netdev/tree_selection success Clearly marked for net-next
netdev/fixes_present success Fixes tag not required for -next series
netdev/subject_prefix success Link
netdev/cover_letter success Series has a cover letter
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 412 this patch: 412
netdev/cc_maintainers warning 5 maintainers not CCed: corbet@lwn.net linux-doc@vger.kernel.org edumazet@google.com kuba@kernel.org pabeni@redhat.com
netdev/build_clang success Errors and warnings before: 299 this patch: 299
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 397 this patch: 397
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 58 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Maxime Chevallier Aug. 1, 2022, 7:37 a.m. UTC
The QUSGMII mode is a derivative of Cisco's USXGMII standard. This
standard is pretty similar to SGMII, but allows for faster speeds, and
has the build-in bits for Quad and Octa variants (like QSGMII).

The main difference with SGMII/QSGMII is that USXGMII/QUSGMII re-uses
the preamble to carry various information, named 'Extensions'.

As of today, the USXGMII standard only mentions the "PCH" extension,
which is used to convey timestamps, allowing in-band signaling of PTP
timestamps without having to modify the frame itself.

This commit adds support for that mode. When no extension is in use, it
behaves exactly like QSGMII, although it's not compatible with QSGMII.

Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
---
V1->V2 : No changes
V2->v3 : Added missing documentation on the new enum value
V3->V4 : Added Andrew's R'd-by

 Documentation/networking/phy.rst | 9 +++++++++
 drivers/net/phy/phylink.c        | 3 +++
 include/linux/phy.h              | 4 ++++
 3 files changed, 16 insertions(+)
diff mbox series

Patch

diff --git a/Documentation/networking/phy.rst b/Documentation/networking/phy.rst
index 704f31da5167..712e44caebd0 100644
--- a/Documentation/networking/phy.rst
+++ b/Documentation/networking/phy.rst
@@ -308,6 +308,15 @@  Some of the interface modes are described below:
     rate of 125Mpbs using a 4B/5B encoding scheme, resulting in an underlying
     data rate of 100Mpbs.
 
+``PHY_INTERFACE_MODE_QUSGMII``
+    This defines the Cisco the Quad USGMII mode, which is the Quad variant of
+    the USGMII (Universal SGMII) link. It's very similar to QSGMII, but uses
+    a Packet Control Header (PCH) instead of the 7 bytes preamble to carry not
+    only the port id, but also so-called "extensions". The only documented
+    extension so-far in the specification is the inclusion of timestamps, for
+    PTP-enabled PHYs. This mode isn't compatible with QSGMII, but offers the
+    same capabilities in terms of link speed and negociation.
+
 Pause frames / flow control
 ===========================
 
diff --git a/drivers/net/phy/phylink.c b/drivers/net/phy/phylink.c
index 9bd69328dc4d..d2455df1d8d2 100644
--- a/drivers/net/phy/phylink.c
+++ b/drivers/net/phy/phylink.c
@@ -321,6 +321,7 @@  void phylink_get_linkmodes(unsigned long *linkmodes, phy_interface_t interface,
 	case PHY_INTERFACE_MODE_RGMII_ID:
 	case PHY_INTERFACE_MODE_RGMII:
 	case PHY_INTERFACE_MODE_QSGMII:
+	case PHY_INTERFACE_MODE_QUSGMII:
 	case PHY_INTERFACE_MODE_SGMII:
 	case PHY_INTERFACE_MODE_GMII:
 		caps |= MAC_1000HD | MAC_1000FD;
@@ -632,6 +633,7 @@  static int phylink_parse_mode(struct phylink *pl, struct fwnode_handle *fwnode)
 		switch (pl->link_config.interface) {
 		case PHY_INTERFACE_MODE_SGMII:
 		case PHY_INTERFACE_MODE_QSGMII:
+		case PHY_INTERFACE_MODE_QUSGMII:
 			phylink_set(pl->supported, 10baseT_Half);
 			phylink_set(pl->supported, 10baseT_Full);
 			phylink_set(pl->supported, 100baseT_Half);
@@ -2929,6 +2931,7 @@  void phylink_mii_c22_pcs_decode_state(struct phylink_link_state *state,
 
 	case PHY_INTERFACE_MODE_SGMII:
 	case PHY_INTERFACE_MODE_QSGMII:
+	case PHY_INTERFACE_MODE_QUSGMII:
 		phylink_decode_sgmii_word(state, lpa);
 		break;
 
diff --git a/include/linux/phy.h b/include/linux/phy.h
index 87638c55d844..9eeab9b9a74c 100644
--- a/include/linux/phy.h
+++ b/include/linux/phy.h
@@ -115,6 +115,7 @@  extern const int phy_10gbit_features_array[1];
  * @PHY_INTERFACE_MODE_25GBASER: 25G BaseR
  * @PHY_INTERFACE_MODE_USXGMII:  Universal Serial 10GE MII
  * @PHY_INTERFACE_MODE_10GKR: 10GBASE-KR - with Clause 73 AN
+ * @PHY_INTERFACE_MODE_QUSGMII: Quad Universal SGMII
  * @PHY_INTERFACE_MODE_MAX: Book keeping
  *
  * Describes the interface between the MAC and PHY.
@@ -152,6 +153,7 @@  typedef enum {
 	PHY_INTERFACE_MODE_USXGMII,
 	/* 10GBASE-KR - with Clause 73 AN */
 	PHY_INTERFACE_MODE_10GKR,
+	PHY_INTERFACE_MODE_QUSGMII,
 	PHY_INTERFACE_MODE_MAX,
 } phy_interface_t;
 
@@ -267,6 +269,8 @@  static inline const char *phy_modes(phy_interface_t interface)
 		return "10gbase-kr";
 	case PHY_INTERFACE_MODE_100BASEX:
 		return "100base-x";
+	case PHY_INTERFACE_MODE_QUSGMII:
+		return "qusgmii";
 	default:
 		return "unknown";
 	}