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From:   Oleksij Rempel <o.rempel@pengutronix.de>
To:     Andrew Lunn <andrew@lunn.ch>,
        "David S. Miller" <davem@davemloft.net>,
        Florian Fainelli <f.fainelli@gmail.com>,
        Heiner Kallweit <hkallweit1@gmail.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Jonathan Corbet <corbet@lwn.net>,
        Michal Kubecek <mkubecek@suse.cz>,
        "John W. Linville" <linville@tuxdriver.com>
Cc:     Oleksij Rempel <o.rempel@pengutronix.de>,
        David Jander <david@protonic.nl>, kernel@pengutronix.de,
        linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
        Russell King <linux@armlinux.org.uk>, mkl@pengutronix.de,
        Marek Vasut <marex@denx.de>,
        Christian Herber <christian.herber@nxp.com>,
        Amit Cohen <amitc@mellanox.com>,
        Petr Machata <petrm@mellanox.com>
Subject: [PATCH ethtool v1] netlink: add master/slave configuration support
Date:   Tue, 26 May 2020 11:10:25 +0200
Message-Id: <20200526091025.25243-1-o.rempel@pengutronix.de>
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Sender: linux-kernel-owner@vger.kernel.org
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This UAPI is needed for BroadR-Reach 100BASE-T1 devices. Due to lack of
auto-negotiation support, we needed to be able to configure the
MASTER-SLAVE role of the port manually or from an application in user
space.

The same UAPI can be used for 1000BASE-T or MultiGBASE-T devices to
force MASTER or SLAVE role. See IEEE 802.3-2018:
22.2.4.3.7 MASTER-SLAVE control register (Register 9)
22.2.4.3.8 MASTER-SLAVE status register (Register 10)
40.5.2 MASTER-SLAVE configuration resolution
45.2.1.185.1 MASTER-SLAVE config value (1.2100.14)
45.2.7.10 MultiGBASE-T AN control 1 register (Register 7.32)

The MASTER-SLAVE role affects the clock configuration:

-------------------------------------------------------------------------------
When the  PHY is configured as MASTER, the PMA Transmit function shall
source TX_TCLK from a local clock source. When configured as SLAVE, the
PMA Transmit function shall source TX_TCLK from the clock recovered from
data stream provided by MASTER.

iMX6Q                     KSZ9031                XXX
------\                /-----------\        /------------\
      |                |           |        |            |
 MAC  |<----RGMII----->| PHY Slave |<------>| PHY Master |
      |<--- 125 MHz ---+-<------/  |        | \          |
------/                \-----------/        \------------/
                                               ^
                                                \-TX_TCLK

-------------------------------------------------------------------------------

Since some clock or link related issues are only reproducible in a
specific MASTER-SLAVE-role, MAC and PHY configuration, it is beneficial
to provide generic (not 100BASE-T1 specific) interface to the user space
for configuration flexibility and trouble shooting.

Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
---
 netlink/desc-ethtool.c       |  2 ++
 netlink/settings.c           | 50 ++++++++++++++++++++++++++++++++++++
 uapi/linux/ethtool.h         | 11 ++++++++
 uapi/linux/ethtool_netlink.h |  2 ++
 4 files changed, 65 insertions(+)

diff --git a/netlink/desc-ethtool.c b/netlink/desc-ethtool.c
index 76c6f13..b0a793c 100644
--- a/netlink/desc-ethtool.c
+++ b/netlink/desc-ethtool.c
@@ -85,6 +85,8 @@ static const struct pretty_nla_desc __linkmodes_desc[] = {
 	NLATTR_DESC_NESTED(ETHTOOL_A_LINKMODES_PEER, bitset),
 	NLATTR_DESC_U32(ETHTOOL_A_LINKMODES_SPEED),
 	NLATTR_DESC_U8(ETHTOOL_A_LINKMODES_DUPLEX),
+	NLATTR_DESC_U8(ETHTOOL_A_LINKMODES_MASTER_SLAVE_CFG),
+	NLATTR_DESC_U8(ETHTOOL_A_LINKMODES_MASTER_SLAVE_STATE),
 };
 
 static const struct pretty_nla_desc __linkstate_desc[] = {
diff --git a/netlink/settings.c b/netlink/settings.c
index 8be5a22..76ca862 100644
--- a/netlink/settings.c
+++ b/netlink/settings.c
@@ -37,6 +37,21 @@ static const char *const names_duplex[] = {
 	[DUPLEX_FULL]		= "Full",
 };
 
+static const char *const names_master_slave_state[] = {
+	[PORT_MODE_STATE_UNKNOWN]	= "Unknown",
+	[PORT_MODE_STATE_MASTER]	= "Master",
+	[PORT_MODE_STATE_SLAVE]		= "Slave",
+	[PORT_MODE_STATE_ERR]		= "Resolution error",
+};
+
+static const char *const names_master_slave_cfg[] = {
+	[PORT_MODE_CFG_UNKNOWN]			= "Unknown",
+	[PORT_MODE_CFG_MASTER_PREFERRED]	= "preferred Master",
+	[PORT_MODE_CFG_SLAVE_PREFERRED]		= "preferred Slave",
+	[PORT_MODE_CFG_MASTER_FORCE]		= "forced Master",
+	[PORT_MODE_CFG_SLAVE_FORCE]		= "forced Slave",
+};
+
 static const char *const names_port[] = {
 	[PORT_TP]		= "Twisted Pair",
 	[PORT_AUI]		= "AUI",
@@ -520,6 +535,25 @@ int linkmodes_reply_cb(const struct nlmsghdr *nlhdr, void *data)
 		printf("\tAuto-negotiation: %s\n",
 		       (autoneg == AUTONEG_DISABLE) ? "off" : "on");
 	}
+	if (tb[ETHTOOL_A_LINKMODES_MASTER_SLAVE_CFG]) {
+		uint8_t val;
+
+		val = mnl_attr_get_u8(tb[ETHTOOL_A_LINKMODES_MASTER_SLAVE_CFG]);
+
+		print_banner(nlctx);
+		print_enum(names_master_slave_cfg,
+			   ARRAY_SIZE(names_master_slave_cfg), val,
+			   "Port mode cfg");
+	}
+	if (tb[ETHTOOL_A_LINKMODES_MASTER_SLAVE_STATE]) {
+		uint8_t val;
+
+		val = mnl_attr_get_u8(tb[ETHTOOL_A_LINKMODES_MASTER_SLAVE_STATE]);
+		print_banner(nlctx);
+		print_enum(names_master_slave_state,
+			   ARRAY_SIZE(names_master_slave_state), val,
+			   "Port mode status");
+	}
 
 	return MNL_CB_OK;
 err:
@@ -827,6 +861,14 @@ static const struct lookup_entry_u32 duplex_values[] = {
 	{}
 };
 
+static const struct lookup_entry_u32 master_slave_values[] = {
+	{ .arg = "master-preferred",	.val = PORT_MODE_CFG_MASTER_PREFERRED },
+	{ .arg = "slave-preferred",	.val = PORT_MODE_CFG_SLAVE_PREFERRED },
+	{ .arg = "master-force",	.val = PORT_MODE_CFG_MASTER_FORCE },
+	{ .arg = "slave-force",		.val = PORT_MODE_CFG_SLAVE_FORCE },
+	{}
+};
+
 char wol_bit_chars[WOL_MODE_COUNT] = {
 	[WAKE_PHY_BIT]		= 'p',
 	[WAKE_UCAST_BIT]	= 'u',
@@ -917,6 +959,14 @@ static const struct param_parser sset_params[] = {
 		.handler_data	= duplex_values,
 		.min_argc	= 1,
 	},
+	{
+		.arg		= "master-slave",
+		.group		= ETHTOOL_MSG_LINKMODES_SET,
+		.type		= ETHTOOL_A_LINKMODES_MASTER_SLAVE_CFG,
+		.handler	= nl_parse_lookup_u8,
+		.handler_data	= master_slave_values,
+		.min_argc	= 1,
+	},
 	{
 		.arg		= "wol",
 		.group		= ETHTOOL_MSG_WOL_SET,
diff --git a/uapi/linux/ethtool.h b/uapi/linux/ethtool.h
index d3dcb45..d2872f9 100644
--- a/uapi/linux/ethtool.h
+++ b/uapi/linux/ethtool.h
@@ -1659,6 +1659,17 @@ static __inline__ int ethtool_validate_duplex(__u8 duplex)
 	return 0;
 }
 
+/* Port mode */
+#define PORT_MODE_CFG_UNKNOWN		1
+#define PORT_MODE_CFG_MASTER_PREFERRED	2
+#define PORT_MODE_CFG_SLAVE_PREFERRED	3
+#define PORT_MODE_CFG_MASTER_FORCE	4
+#define PORT_MODE_CFG_SLAVE_FORCE	5
+#define PORT_MODE_STATE_UNKNOWN		1
+#define PORT_MODE_STATE_MASTER		2
+#define PORT_MODE_STATE_SLAVE		3
+#define PORT_MODE_STATE_ERR		4
+
 /* Which connector port. */
 #define PORT_TP			0x00
 #define PORT_AUI		0x01
diff --git a/uapi/linux/ethtool_netlink.h b/uapi/linux/ethtool_netlink.h
index ad6d3a0..73a720c 100644
--- a/uapi/linux/ethtool_netlink.h
+++ b/uapi/linux/ethtool_netlink.h
@@ -185,6 +185,8 @@ enum {
 	ETHTOOL_A_LINKMODES_PEER,		/* bitset */
 	ETHTOOL_A_LINKMODES_SPEED,		/* u32 */
 	ETHTOOL_A_LINKMODES_DUPLEX,		/* u8 */
+	ETHTOOL_A_LINKMODES_MASTER_SLAVE_CFG,	/* u8 */
+	ETHTOOL_A_LINKMODES_MASTER_SLAVE_STATE,	/* u8 */
 
 	/* add new constants above here */
 	__ETHTOOL_A_LINKMODES_CNT,
-- 
2.26.2