[PATCH net-next v4 0/4] Support for RollBall 10G copper SFP modules

@@ -3,6 +3,7 @@
  * MDIO I2C bridge
  *
  * Copyright (C) 2015-2016 Russell King
+ * Copyright (C) 2021 Marek Behun
  *
  * Network PHYs can appear on I2C buses when they are part of SFP module.
  * This driver exposes these PHYs to the networking PHY code, allowing

@@ -12,6 +13,7 @@
 #include <linux/i2c.h>
 #include <linux/mdio/mdio-i2c.h>
 #include <linux/phy.h>
+#include <linux/sfp.h>
 
 /*
  * I2C bus addresses 0x50 and 0x51 are normally an EEPROM, which is

@@ -28,7 +30,7 @@ static unsigned int i2c_mii_phy_addr(int phy_id)
 	return phy_id + 0x40;
 }
 
-static int i2c_mii_read(struct mii_bus *bus, int phy_id, int reg)
+static int i2c_mii_read_default(struct mii_bus *bus, int phy_id, int reg)
 {
 	struct i2c_adapter *i2c = bus->priv;
 	struct i2c_msg msgs[2];

@@ -62,7 +64,8 @@ static int i2c_mii_read(struct mii_bus *bus, int phy_id, int reg)
 	return data[0] << 8 | data[1];
 }
 
-static int i2c_mii_write(struct mii_bus *bus, int phy_id, int reg, u16 val)
+static int i2c_mii_write_default(struct mii_bus *bus, int phy_id, int reg,
+				 u16 val)
 {
 	struct i2c_adapter *i2c = bus->priv;
 	struct i2c_msg msg;

@@ -91,9 +94,297 @@ static int i2c_mii_write(struct mii_bus *bus, int phy_id, int reg, u16 val)
 	return ret < 0 ? ret : 0;
 }
 
-struct mii_bus *mdio_i2c_alloc(struct device *parent, struct i2c_adapter *i2c)
+/* RollBall SFPs do not access internal PHY via I2C address 0x56, but
+ * instead via address 0x51, when SFP page is set to 0x03 and password to
+ * 0xffffffff.
+ * Since current SFP code does not modify SFP_PAGE, we set it to 0x03 only at
+ * bus creation time, and expect it to remain set to 0x03 throughout the
+ * lifetime of the module plugged into the system. If the SFP code starts
+ * modifying SFP_PAGE in the future, this code will need to change.
+ *
+ * address  size  contents  description
+ * -------  ----  --------  -----------
+ * 0x80     1     CMD       0x01/0x02/0x04 for write/read/done
+ * 0x81     1     DEV       Clause 45 device
+ * 0x82     2     REG       Clause 45 register
+ * 0x84     2     VAL       Register value
+ */
+#define ROLLBALL_PHY_I2C_ADDR		0x51
+#define ROLLBALL_SFP_PASSWORD_ADDR	0x7b
+
+#define ROLLBALL_CMD_ADDR		0x80
+#define ROLLBALL_DATA_ADDR		0x81
+
+#define ROLLBALL_CMD_WRITE		0x01
+#define ROLLBALL_CMD_READ		0x02
+#define ROLLBALL_CMD_DONE		0x04
+
+#define SFP_PAGE_ROLLBALL_MDIO		3
+
+static int __i2c_transfer_err(struct i2c_adapter *i2c, struct i2c_msg *msgs,
+			      int num)
+{
+	int ret;
+
+	ret = __i2c_transfer(i2c, msgs, num);
+	if (ret < 0)
+		return ret;
+	else if (ret != num)
+		return -EIO;
+	else
+		return 0;
+}
+
+static int __i2c_rollball_get_page(struct i2c_adapter *i2c, int bus_addr,
+				   u8 *page)
+{
+	struct i2c_msg msgs[2];
+	u8 addr = SFP_PAGE;
+
+	msgs[0].addr = bus_addr;
+	msgs[0].flags = 0;
+	msgs[0].len = 1;
+	msgs[0].buf = &addr;
+
+	msgs[1].addr = bus_addr;
+	msgs[1].flags = I2C_M_RD;
+	msgs[1].len = 1;
+	msgs[1].buf = page;
+
+	return __i2c_transfer_err(i2c, msgs, 2);
+}
+
+static int __i2c_rollball_set_page(struct i2c_adapter *i2c, int bus_addr,
+				   u8 page)
+{
+	struct i2c_msg msg;
+	u8 buf[2];
+
+	buf[0] = SFP_PAGE;
+	buf[1] = page;
+
+	msg.addr = bus_addr;
+	msg.flags = 0;
+	msg.len = 2;
+	msg.buf = buf;
+
+	return __i2c_transfer_err(i2c, &msg, 1);
+}
+
+/* In order to not interfere with other SFP code (which possibly may manipulate
+ * SFP_PAGE), for every transfer we do this:
+ *   1. lock the bus
+ *   2. save content of SFP_PAGE
+ *   3. set SFP_PAGE to 3
+ *   4. do the transfer
+ *   5. restore original SFP_PAGE
+ *   6. unlock the bus
+ * Note that one might think that steps 2 to 5 could be theoretically done all
+ * in one call to i2c_transfer (by constructing msgs array in such a way), but
+ * unfortunately tests show that this does not work :-( Changed SFP_PAGE does
+ * not take into account until i2c_transfer() is done.
+ */
+static int i2c_transfer_rollball(struct i2c_adapter *i2c,
+				 struct i2c_msg *msgs, int num)
+{
+	u8 saved_page;
+	int ret;
+
+	i2c_lock_bus(i2c, I2C_LOCK_SEGMENT);
+
+	/* save original page */
+	ret = __i2c_rollball_get_page(i2c, msgs->addr, &saved_page);
+	if (ret)
+		goto unlock;
+
+	/* change to RollBall MDIO page */
+	ret = __i2c_rollball_set_page(i2c, msgs->addr, SFP_PAGE_ROLLBALL_MDIO);
+	if (ret)
+		goto unlock;
+
+	/* do the transfer */
+	ret = __i2c_transfer_err(i2c, msgs, num);
+	if (ret)
+		goto unlock;
+
+	/* restore original page */
+	ret = __i2c_rollball_set_page(i2c, msgs->addr, saved_page);
+
+unlock:
+	i2c_unlock_bus(i2c, I2C_LOCK_SEGMENT);
+
+	return ret;
+}
+
+static int i2c_rollball_mii_poll(struct mii_bus *bus, int bus_addr, u8 *buf,
+				 size_t len)
+{
+	struct i2c_adapter *i2c = bus->priv;
+	struct i2c_msg msgs[2];
+	u8 cmd_addr, tmp, *res;
+	int i, ret;
+
+	cmd_addr = ROLLBALL_CMD_ADDR;
+
+	res = buf ? buf : &tmp;
+	len = buf ? len : 1;
+
+	msgs[0].addr = bus_addr;
+	msgs[0].flags = 0;
+	msgs[0].len = 1;
+	msgs[0].buf = &cmd_addr;
+
+	msgs[1].addr = bus_addr;
+	msgs[1].flags = I2C_M_RD;
+	msgs[1].len = len;
+	msgs[1].buf = res;
+
+	/* By experiment it takes up to 70 ms to access a register for these
+	 * SFPs. Sleep 20ms between iteratios and try 10 times.
+	 */
+	i = 10;
+	do {
+		msleep(20);
+
+		ret = i2c_transfer_rollball(i2c, msgs, ARRAY_SIZE(msgs));
+		if (ret)
+			return ret;
+
+		if (*res == ROLLBALL_CMD_DONE)
+			return 0;
+	} while (i-- > 0);
+
+	dev_dbg(&bus->dev, "poll timed out\n");
+
+	return -ETIMEDOUT;
+}
+
+static int i2c_rollball_mii_cmd(struct mii_bus *bus, int bus_addr, u8 cmd,
+				u8 *data, size_t len)
+{
+	struct i2c_adapter *i2c = bus->priv;
+	struct i2c_msg msgs[2];
+	u8 cmdbuf[2];
+
+	cmdbuf[0] = ROLLBALL_CMD_ADDR;
+	cmdbuf[1] = cmd;
+
+	msgs[0].addr = bus_addr;
+	msgs[0].flags = 0;
+	msgs[0].len = len;
+	msgs[0].buf = data;
+
+	msgs[1].addr = bus_addr;
+	msgs[1].flags = 0;
+	msgs[1].len = sizeof(cmdbuf);
+	msgs[1].buf = cmdbuf;
+
+	return i2c_transfer_rollball(i2c, msgs, ARRAY_SIZE(msgs));
+}
+
+static int i2c_mii_read_rollball(struct mii_bus *bus, int phy_id, int reg)
+{
+	u8 buf[4], res[6];
+	int bus_addr, ret;
+	u16 val;
+
+	if (!(reg & MII_ADDR_C45))
+		return -EOPNOTSUPP;
+
+	bus_addr = i2c_mii_phy_addr(phy_id);
+	if (bus_addr != ROLLBALL_PHY_I2C_ADDR)
+		return 0xffff;
+
+	buf[0] = ROLLBALL_DATA_ADDR;
+	buf[1] = (reg >> 16) & 0x1f;
+	buf[2] = (reg >> 8) & 0xff;
+	buf[3] = reg & 0xff;
+
+	ret = i2c_rollball_mii_cmd(bus, bus_addr, ROLLBALL_CMD_READ, buf,
+				   sizeof(buf));
+	if (ret < 0)
+		return ret;
+
+	ret = i2c_rollball_mii_poll(bus, bus_addr, res, sizeof(res));
+	if (ret == -ETIMEDOUT)
+		return 0xffff;
+	else if (ret < 0)
+		return ret;
+
+	val = res[4] << 8 | res[5];
+
+	dev_dbg(&bus->dev, "read reg %02x:%04x = %04x\n", (reg >> 16) & 0x1f,
+		reg & 0xffff, val);
+
+	return val;
+}
+
+static int i2c_mii_write_rollball(struct mii_bus *bus, int phy_id, int reg,
+				  u16 val)
+{
+	int bus_addr, ret;
+	u8 buf[6];
+
+	if (!(reg & MII_ADDR_C45))
+		return -EOPNOTSUPP;
+
+	bus_addr = i2c_mii_phy_addr(phy_id);
+	if (bus_addr != ROLLBALL_PHY_I2C_ADDR)
+		return 0;
+
+	buf[0] = ROLLBALL_DATA_ADDR;
+	buf[1] = (reg >> 16) & 0x1f;
+	buf[2] = (reg >> 8) & 0xff;
+	buf[3] = reg & 0xff;
+	buf[4] = val >> 8;
+	buf[5] = val & 0xff;
+
+	ret = i2c_rollball_mii_cmd(bus, bus_addr, ROLLBALL_CMD_WRITE, buf,
+				   sizeof(buf));
+	if (ret < 0)
+		return ret;
+
+	ret = i2c_rollball_mii_poll(bus, bus_addr, NULL, 0);
+	if (ret < 0)
+		return ret;
+
+	dev_dbg(&bus->dev, "write reg %02x:%04x = %04x\n", (reg >> 16) & 0x1f,
+		reg & 0xffff, val);
+
+	return 0;
+}
+
+static int i2c_mii_init_rollball(struct i2c_adapter *i2c)
+{
+	struct i2c_msg msg;
+	u8 pw[5];
+	int ret;
+
+	pw[0] = ROLLBALL_SFP_PASSWORD_ADDR;
+	pw[1] = 0xff;
+	pw[2] = 0xff;
+	pw[3] = 0xff;
+	pw[4] = 0xff;
+
+	msg.addr = ROLLBALL_PHY_I2C_ADDR;
+	msg.flags = 0;
+	msg.len = sizeof(pw);
+	msg.buf = pw;
+
+	ret = i2c_transfer(i2c, &msg, 1);
+	if (ret < 0)
+		return ret;
+	else if (ret != 1)
+		return -EIO;
+	else
+		return 0;
+}
+
+struct mii_bus *mdio_i2c_alloc(struct device *parent, struct i2c_adapter *i2c,
+			       enum mdio_i2c_proto protocol)
 {
 	struct mii_bus *mii;
+	int ret;
 
 	if (!i2c_check_functionality(i2c, I2C_FUNC_I2C))
 		return ERR_PTR(-EINVAL);

@@ -104,10 +395,28 @@ struct mii_bus *mdio_i2c_alloc(struct device *parent, struct i2c_adapter *i2c)
 
 	snprintf(mii->id, MII_BUS_ID_SIZE, "i2c:%s", dev_name(parent));
 	mii->parent = parent;
-	mii->read = i2c_mii_read;
-	mii->write = i2c_mii_write;
 	mii->priv = i2c;
 
+	switch (protocol) {
+	case MDIO_I2C_ROLLBALL:
+		ret = i2c_mii_init_rollball(i2c);
+		if (ret < 0) {
+			dev_err(parent,
+				"Cannot initialize RollBall MDIO I2C protocol: %d\n",
+				ret);
+			mdiobus_free(mii);
+			return ERR_PTR(ret);
+		}
+
+		mii->read = i2c_mii_read_rollball;
+		mii->write = i2c_mii_write_rollball;
+		break;
+	default:
+		mii->read = i2c_mii_read_default;
+		mii->write = i2c_mii_write_default;
+		break;
+	}
+
 	return mii;
 }
 EXPORT_SYMBOL_GPL(mdio_i2c_alloc);

@@ -419,7 +419,7 @@ static int sfp_i2c_configure(struct sfp *sfp, struct i2c_adapter *i2c)
 	sfp->read = sfp_i2c_read;
 	sfp->write = sfp_i2c_write;
 
-	i2c_mii = mdio_i2c_alloc(sfp->dev, i2c);
+	i2c_mii = mdio_i2c_alloc(sfp->dev, i2c, MDIO_I2C_DEFAULT);
 	if (IS_ERR(i2c_mii))
 		return PTR_ERR(i2c_mii);
 

@@ -11,6 +11,12 @@ struct device;
 struct i2c_adapter;
 struct mii_bus;
 
-struct mii_bus *mdio_i2c_alloc(struct device *parent, struct i2c_adapter *i2c);
+enum mdio_i2c_proto {
+	MDIO_I2C_DEFAULT,
+	MDIO_I2C_ROLLBALL,
+};
+
+struct mii_bus *mdio_i2c_alloc(struct device *parent, struct i2c_adapter *i2c,
+			       enum mdio_i2c_proto protocol);
 
 #endif

@@ -165,6 +165,7 @@ static const enum gpiod_flags gpio_flags[] = {
  * on board (for a copper SFP) time to initialise.
  */
 #define T_WAIT			msecs_to_jiffies(50)
+#define T_WAIT_ROLLBALL		msecs_to_jiffies(25000)
 #define T_START_UP		msecs_to_jiffies(300)
 #define T_START_UP_BAD_GPON	msecs_to_jiffies(60000)
 

@@ -204,8 +205,11 @@ static const enum gpiod_flags gpio_flags[] = {
 
 /* SFP modules appear to always have their PHY configured for bus address
  * 0x56 (which with mdio-i2c, translates to a PHY address of 22).
+ * RollBall SFPs access phy via SFP Enhanced Digital Diagnostic Interface
+ * via address 0x51 (mdio-i2c will use RollBall protocol on this address).
  */
-#define SFP_PHY_ADDR	22
+#define SFP_PHY_ADDR		22
+#define SFP_PHY_ADDR_ROLLBALL	17
 
 struct sff_data {
 	unsigned int gpios;

@@ -218,6 +222,7 @@ struct sfp {
 	struct mii_bus *i2c_mii;
 	struct sfp_bus *sfp_bus;
 	enum mdio_i2c_proto mdio_protocol;
+	int phy_addr;
 	struct phy_device *mod_phy;
 	const struct sff_data *type;
 	size_t i2c_block_size;

@@ -250,6 +255,7 @@ struct sfp {
 	struct sfp_eeprom_id id;
 	unsigned int module_power_mW;
 	unsigned int module_t_start_up;
+	unsigned int module_t_wait;
 
 #if IS_ENABLED(CONFIG_HWMON)
 	struct sfp_diag diag;

@@ -1453,7 +1459,7 @@ static int sfp_sm_probe_phy(struct sfp *sfp, bool is_c45)
 	struct phy_device *phy;
 	int err;
 
-	phy = get_phy_device(sfp->i2c_mii, SFP_PHY_ADDR, is_c45);
+	phy = get_phy_device(sfp->i2c_mii, sfp->phy_addr, is_c45);
 	if (phy == ERR_PTR(-ENODEV))
 		return PTR_ERR(phy);
 	if (IS_ERR(phy)) {

@@ -1835,6 +1841,23 @@ static int sfp_sm_mod_probe(struct sfp *sfp, bool report)
 
 	sfp->mdio_protocol = MDIO_I2C_DEFAULT;
 
+	sfp->phy_addr = SFP_PHY_ADDR;
+	sfp->module_t_wait = T_WAIT;
+
+	if (((!memcmp(id.base.vendor_name, "OEM             ", 16) ||
+	      !memcmp(id.base.vendor_name, "Turris          ", 16)) &&
+	     (!memcmp(id.base.vendor_pn, "SFP-10G-T       ", 16) ||
+	      !memcmp(id.base.vendor_pn, "RTSFP-10", 8)))) {
+		sfp->mdio_protocol = MDIO_I2C_ROLLBALL;
+		sfp->phy_addr = SFP_PHY_ADDR_ROLLBALL;
+		sfp->module_t_wait = T_WAIT_ROLLBALL;
+
+		/* RollBall SFPs may have wrong (zero) extended compliacne code
+		 * burned in EEPROM. For PHY probing we need the correct one.
+		 */
+		id.base.extended_cc = SFF8024_ECC_10GBASE_T_SFI;
+	}
+
 	return 0;
 }
 

@@ -2030,9 +2053,10 @@ static void sfp_sm_main(struct sfp *sfp, unsigned int event)
 
 		/* We need to check the TX_FAULT state, which is not defined
 		 * while TX_DISABLE is asserted. The earliest we want to do
-		 * anything (such as probe for a PHY) is 50ms.
+		 * anything (such as probe for a PHY) is 50ms. (or more on
+		 * specific modules).
 		 */
-		sfp_sm_next(sfp, SFP_S_WAIT, T_WAIT);
+		sfp_sm_next(sfp, SFP_S_WAIT, sfp->module_t_wait);
 		break;
 
 	case SFP_S_WAIT:

@@ -2046,8 +2070,8 @@ static void sfp_sm_main(struct sfp *sfp, unsigned int event)
 			 * deasserting.
 			 */
 			timeout = sfp->module_t_start_up;
-			if (timeout > T_WAIT)
-				timeout -= T_WAIT;
+			if (timeout > sfp->module_t_wait)
+				timeout -= sfp->module_t_wait;
 			else
 				timeout = 1;
 

@@ -1018,7 +1018,7 @@ static int phylink_attach_phy(struct phylink *pl, struct phy_device *phy,
 {
 	if (WARN_ON(pl->cfg_link_an_mode == MLO_AN_FIXED ||
 		    (pl->cfg_link_an_mode == MLO_AN_INBAND &&
-		     phy_interface_mode_is_8023z(interface))))
+		     phy_interface_mode_is_8023z(interface) && !pl->sfp_bus)))
 		return -EINVAL;
 
 	if (pl->phydev)

@@ -2069,9 +2069,6 @@ static int phylink_sfp_config(struct phylink *pl, u8 mode,
 		    phylink_an_mode_str(mode), phy_modes(config.interface),
 		    __ETHTOOL_LINK_MODE_MASK_NBITS, support);
 
-	if (phy_interface_mode_is_8023z(iface) && pl->phydev)
-		return -EINVAL;
-
 	changed = !linkmode_equal(pl->supported, support);
 	if (changed) {
 		linkmode_copy(pl->supported, support);

@@ -217,6 +217,7 @@ struct sfp {
 	struct i2c_adapter *i2c;
 	struct mii_bus *i2c_mii;
 	struct sfp_bus *sfp_bus;
+	enum mdio_i2c_proto mdio_protocol;
 	struct phy_device *mod_phy;
 	const struct sff_data *type;
 	size_t i2c_block_size;

@@ -409,9 +410,6 @@ static int sfp_i2c_write(struct sfp *sfp, bool a2, u8 dev_addr, void *buf,
 
 static int sfp_i2c_configure(struct sfp *sfp, struct i2c_adapter *i2c)
 {
-	struct mii_bus *i2c_mii;
-	int ret;
-
 	if (!i2c_check_functionality(i2c, I2C_FUNC_I2C))
 		return -EINVAL;
 

@@ -419,7 +417,15 @@ static int sfp_i2c_configure(struct sfp *sfp, struct i2c_adapter *i2c)
 	sfp->read = sfp_i2c_read;
 	sfp->write = sfp_i2c_write;
 
-	i2c_mii = mdio_i2c_alloc(sfp->dev, i2c, MDIO_I2C_DEFAULT);
+	return 0;
+}
+
+static int sfp_i2c_mdiobus_create(struct sfp *sfp)
+{
+	struct mii_bus *i2c_mii;
+	int ret;
+
+	i2c_mii = mdio_i2c_alloc(sfp->dev, sfp->i2c, sfp->mdio_protocol);
 	if (IS_ERR(i2c_mii))
 		return PTR_ERR(i2c_mii);
 

@@ -437,6 +443,12 @@ static int sfp_i2c_configure(struct sfp *sfp, struct i2c_adapter *i2c)
 	return 0;
 }
 
+static void sfp_i2c_mdiobus_destroy(struct sfp *sfp)
+{
+	mdiobus_unregister(sfp->i2c_mii);
+	sfp->i2c_mii = NULL;
+}
+
 /* Interface */
 static int sfp_read(struct sfp *sfp, bool a2, u8 addr, void *buf, size_t len)
 {

@@ -1821,6 +1833,8 @@ static int sfp_sm_mod_probe(struct sfp *sfp, bool report)
 	else
 		sfp->module_t_start_up = T_START_UP;
 
+	sfp->mdio_protocol = MDIO_I2C_DEFAULT;
+
 	return 0;
 }
 

@@ -1991,6 +2005,8 @@ static void sfp_sm_main(struct sfp *sfp, unsigned int event)
 			sfp_module_stop(sfp->sfp_bus);
 		if (sfp->mod_phy)
 			sfp_sm_phy_detach(sfp);
+		if (sfp->i2c_mii)
+			sfp_i2c_mdiobus_destroy(sfp);
 		sfp_module_tx_disable(sfp);
 		sfp_soft_stop_poll(sfp);
 		sfp_sm_next(sfp, SFP_S_DOWN, 0);

@@ -2053,6 +2069,12 @@ static void sfp_sm_main(struct sfp *sfp, unsigned int event)
 				     sfp->sm_fault_retries == N_FAULT_INIT);
 		} else if (event == SFP_E_TIMEOUT || event == SFP_E_TX_CLEAR) {
 	init_done:
+			/* Create mdiobus and start trying for PHY */
+			ret = sfp_i2c_mdiobus_create(sfp);
+			if (ret < 0) {
+				sfp_sm_next(sfp, SFP_S_FAIL, 0);
+				break;
+			}
 			sfp->sm_phy_retries = R_PHY_RETRY;
 			goto phy_probe;
 		}