From 5d84f16b0036b33487b94abef15ad3c224c81ee9 Mon Sep 17 00:00:00 2001
From: Daniel Golle <daniel@makrotopia.org>
Date: Thu, 3 Feb 2022 16:38:50 +0000
Subject: [PATCH] net: mdio: support hardware-assisted indirect access

MDIO controllers found in Switch-SoCs can offload some MDIO operations
to the hardware:
 * MMD register access via Clause-22
   Instead of using multiple operations to access MMD registers via
   MII register MII_MMD_CTRL and MII_MMD_DATA some controllers
   allow transparent access to MMD PHY registers.

 * paged MII register access
   Some PHYs (namely RealTek and Vitesse) use vendor-defined MII
   register 0x1f for paged access. Some MDIO host controllers support
   transparent paged access when used with such PHYs.

 * add convenience accessors to fully support paged access also on
   multi-PHY packages (like the embedded PHYs in RTL83xx):
   phy_package_read_paged and phy_package_write_paged
   phy_package_port_read and phy_package_port_write
   phy_package_port_read_paged and phy_package_port_write_paged

Signed-off-by: Daniel Golle <daniel@makrotopia.org>
---
 drivers/net/phy/mdio_bus.c | 335 ++++++++++++++++++++++++++++++++++++-
 drivers/net/phy/phy-core.c |  66 +++++++-
 include/linux/mdio.h       |  59 +++++++
 include/linux/phy.h        | 129 ++++++++++++++
 include/uapi/linux/mii.h   |   1 +
 5 files changed, 580 insertions(+), 10 deletions(-)

--- a/drivers/net/phy/mdio_bus.c
+++ b/drivers/net/phy/mdio_bus.c
@@ -739,6 +739,32 @@ out:
 }
 
 /**
+ * __mdiobus_select_page - Unlocked version of the mdiobus_select_page function
+ * @bus: the mii_bus struct
+ * @addr: the phy address
+ * @page: register page to select
+ *
+ * Selects a MDIO bus register page. Caller must hold the mdio bus lock.
+ *
+ * NOTE: MUST NOT be called from interrupt context.
+ */
+int __mdiobus_select_page(struct mii_bus *bus, int addr, u16 page)
+{
+	lockdep_assert_held_once(&bus->mdio_lock);
+
+	if (bus->selected_page[addr] == page)
+		return 0;
+
+	bus->selected_page[addr] = page;
+	if (bus->read_paged)
+		return 0;
+
+	return bus->write(bus, addr, MII_MAINPAGE, page);
+
+}
+EXPORT_SYMBOL(__mdiobus_select_page);
+
+/**
  * __mdiobus_read - Unlocked version of the mdiobus_read function
  * @bus: the mii_bus struct
  * @addr: the phy address
@@ -754,7 +780,10 @@ int __mdiobus_read(struct mii_bus *bus,
 
 	WARN_ON_ONCE(!mutex_is_locked(&bus->mdio_lock));
 
-	retval = bus->read(bus, addr, regnum);
+	if (bus->read_paged)
+		retval = bus->read_paged(bus, addr, bus->selected_page[addr], regnum);
+	else
+		retval = bus->read(bus, addr, regnum);
 
 	trace_mdio_access(bus, 1, addr, regnum, retval, retval);
 	mdiobus_stats_acct(&bus->stats[addr], true, retval);
@@ -764,6 +793,40 @@ int __mdiobus_read(struct mii_bus *bus,
 EXPORT_SYMBOL(__mdiobus_read);
 
 /**
+ * __mdiobus_read_paged - Unlocked version of the mdiobus_read_paged function
+ * @bus: the mii_bus struct
+ * @addr: the phy address
+ * @page: the register page to access
+ * @regnum: register number to read
+ *
+ * Read a MDIO bus register. Caller must hold the mdio bus lock.
+ *
+ * NOTE: MUST NOT be called from interrupt context.
+ */
+int __mdiobus_read_paged(struct mii_bus *bus, int addr, u16 page, u32 regnum)
+{
+	int retval;
+	int oldpage;
+
+	lockdep_assert_held_once(&bus->mdio_lock);
+
+	if (bus->read_paged) {
+		retval = bus->read_paged(bus, addr, page, regnum);
+	} else {
+		oldpage = bus->selected_page[addr];
+		__mdiobus_select_page(bus, addr, page);
+		retval = bus->read(bus, addr, regnum);
+		__mdiobus_select_page(bus, addr, oldpage);
+	}
+
+	trace_mdio_access(bus, 1, addr, regnum, retval, retval);
+	mdiobus_stats_acct(&bus->stats[addr], true, retval);
+
+	return retval;
+}
+EXPORT_SYMBOL(__mdiobus_read_paged);
+
+/**
  * __mdiobus_write - Unlocked version of the mdiobus_write function
  * @bus: the mii_bus struct
  * @addr: the phy address
@@ -780,7 +843,10 @@ int __mdiobus_write(struct mii_bus *bus,
 
 	WARN_ON_ONCE(!mutex_is_locked(&bus->mdio_lock));
 
-	err = bus->write(bus, addr, regnum, val);
+	if (bus->write_paged)
+		err = bus->write_paged(bus, addr, bus->selected_page[addr], regnum, val);
+	else
+		err = bus->write(bus, addr, regnum, val);
 
 	trace_mdio_access(bus, 0, addr, regnum, val, err);
 	mdiobus_stats_acct(&bus->stats[addr], false, err);
@@ -790,6 +856,39 @@ int __mdiobus_write(struct mii_bus *bus,
 EXPORT_SYMBOL(__mdiobus_write);
 
 /**
+ * __mdiobus_write_paged - Unlocked version of the mdiobus_write_paged function
+ * @bus: the mii_bus struct
+ * @addr: the phy address
+ * @page: the register page to access
+ * @regnum: register number to write
+ * @val: value to write to @regnum
+ *
+ * Write a MDIO bus register. Caller must hold the mdio bus lock.
+ *
+ * NOTE: MUST NOT be called from interrupt context.
+ */
+int __mdiobus_write_paged(struct mii_bus *bus, int addr, u16 page, u32 regnum, u16 val)
+{
+	int err, oldpage;
+
+	lockdep_assert_held_once(&bus->mdio_lock);
+
+	if (bus->write_paged) {
+		err = bus->write_paged(bus, addr, page, regnum, val);
+	} else {
+		oldpage = bus->selected_page[addr];
+		__mdiobus_select_page(bus, addr, page);
+		err = bus->write(bus, addr, regnum, val);
+		__mdiobus_select_page(bus, addr, oldpage);
+	}
+	trace_mdio_access(bus, 0, addr, regnum, val, err);
+	mdiobus_stats_acct(&bus->stats[addr], false, err);
+	return err;
+}
+EXPORT_SYMBOL(__mdiobus_write_paged);
+
+
+/**
  * __mdiobus_modify_changed - Unlocked version of the mdiobus_modify function
  * @bus: the mii_bus struct
  * @addr: the phy address
@@ -822,6 +921,43 @@ int __mdiobus_modify_changed(struct mii_
 EXPORT_SYMBOL_GPL(__mdiobus_modify_changed);
 
 /**
+ * __mdiobus_modify_changed_paged - Unlocked version of the mdiobus_modify_paged function
+ * @bus: the mii_bus struct
+ * @addr: the phy address
+ * @regnum: register number to modify
+ * @mask: bit mask of bits to clear
+ * @set: bit mask of bits to set
+ *
+ * Read, modify, and if any change, write the register value back to the
+ * device. Any error returns a negative number.
+ *
+ * NOTE: MUST NOT be called from interrupt context.
+ */
+int __mdiobus_modify_changed_paged(struct mii_bus *bus, int addr, u32 regnum, u16 page,
+				   u16 mask, u16 set)
+{
+	int new, ret, oldpage;
+
+	oldpage = bus->selected_page[addr];
+	__mdiobus_select_page(bus, addr, page);
+
+	ret = __mdiobus_read_paged(bus, addr, page, regnum);
+	if (ret < 0)
+		return ret;
+
+	new = (ret & ~mask) | set;
+	if (new == ret)
+		return 0;
+
+	ret = __mdiobus_write_paged(bus, addr, page, regnum, new);
+
+	__mdiobus_select_page(bus, addr, oldpage);
+
+	return ret < 0 ? ret : 1;
+}
+EXPORT_SYMBOL_GPL(__mdiobus_modify_changed_paged);
+
+/**
  * mdiobus_read_nested - Nested version of the mdiobus_read function
  * @bus: the mii_bus struct
  * @addr: the phy address
@@ -847,6 +983,79 @@ int mdiobus_read_nested(struct mii_bus *
 EXPORT_SYMBOL(mdiobus_read_nested);
 
 /**
+ * mdiobus_select_page_nested - Nested version of the mdiobus_select_page function
+ * @bus: the mii_bus struct
+ * @addr: the phy address
+ * @page: register page to access
+ *
+ * In case of nested MDIO bus access avoid lockdep false positives by
+ * using mutex_lock_nested().
+ *
+ * NOTE: MUST NOT be called from interrupt context,
+ * because the bus read/write functions may wait for an interrupt
+ * to conclude the operation.
+ */
+int mdiobus_select_page_nested(struct mii_bus *bus, int addr, u16 page)
+{
+	int retval;
+
+	mutex_lock_nested(&bus->mdio_lock, MDIO_MUTEX_NESTED);
+	retval = __mdiobus_select_page(bus, addr, page);
+	mutex_unlock(&bus->mdio_lock);
+
+	return retval;
+}
+EXPORT_SYMBOL(mdiobus_select_page_nested);
+
+/**
+ * mdiobus_read_paged_nested - Nested version of the mdiobus_read_paged function
+ * @bus: the mii_bus struct
+ * @addr: the phy address
+ * @page: register page to access
+ * @regnum: register number to read
+ *
+ * In case of nested MDIO bus access avoid lockdep false positives by
+ * using mutex_lock_nested().
+ *
+ * NOTE: MUST NOT be called from interrupt context,
+ * because the bus read/write functions may wait for an interrupt
+ * to conclude the operation.
+ */
+int mdiobus_read_paged_nested(struct mii_bus *bus, int addr, u16 page, u32 regnum)
+{
+	int retval;
+
+	mutex_lock_nested(&bus->mdio_lock, MDIO_MUTEX_NESTED);
+	retval = __mdiobus_read_paged(bus, addr, page, regnum);
+	mutex_unlock(&bus->mdio_lock);
+
+	return retval;
+}
+EXPORT_SYMBOL(mdiobus_read_paged_nested);
+
+/**
+ * mdiobus_select_page - Convenience function for setting the MII register page
+ * @bus: the mii_bus struct
+ * @addr: the phy address
+ * @page: the register page to set
+ *
+ * NOTE: MUST NOT be called from interrupt context,
+ * because the bus read/write functions may wait for an interrupt
+ * to conclude the operation.
+ */
+int mdiobus_select_page(struct mii_bus *bus, int addr, u16 page)
+{
+	int retval;
+
+	mutex_lock(&bus->mdio_lock);
+	retval = __mdiobus_select_page(bus, addr, page);
+	mutex_unlock(&bus->mdio_lock);
+
+	return retval;
+}
+EXPORT_SYMBOL(mdiobus_select_page);
+
+/**
  * mdiobus_read - Convenience function for reading a given MII mgmt register
  * @bus: the mii_bus struct
  * @addr: the phy address
@@ -869,6 +1078,29 @@ int mdiobus_read(struct mii_bus *bus, in
 EXPORT_SYMBOL(mdiobus_read);
 
 /**
+ * mdiobus_read_paged - Convenience function for reading a given paged MII mgmt register
+ * @bus: the mii_bus struct
+ * @addr: the phy address
+ * @page: register page to access
+ * @regnum: register number to read
+ *
+ * NOTE: MUST NOT be called from interrupt context,
+ * because the bus read/write functions may wait for an interrupt
+ * to conclude the operation.
+ */
+int mdiobus_read_paged(struct mii_bus *bus, int addr, u16 page, u32 regnum)
+{
+	int retval;
+
+	mutex_lock(&bus->mdio_lock);
+	retval = __mdiobus_read_paged(bus, addr, page, regnum);
+	mutex_unlock(&bus->mdio_lock);
+
+	return retval;
+}
+EXPORT_SYMBOL(mdiobus_read_paged);
+
+/**
  * mdiobus_write_nested - Nested version of the mdiobus_write function
  * @bus: the mii_bus struct
  * @addr: the phy address
@@ -895,6 +1127,33 @@ int mdiobus_write_nested(struct mii_bus
 EXPORT_SYMBOL(mdiobus_write_nested);
 
 /**
+ * mdiobus_write_paged_nested - Nested version of the mdiobus_write_aged function
+ * @bus: the mii_bus struct
+ * @addr: the phy address
+ * @page: the register page to access
+ * @regnum: register number to write
+ * @val: value to write to @regnum
+ *
+ * In case of nested MDIO bus access avoid lockdep false positives by
+ * using mutex_lock_nested().
+ *
+ * NOTE: MUST NOT be called from interrupt context,
+ * because the bus read/write functions may wait for an interrupt
+ * to conclude the operation.
+ */
+int mdiobus_write_paged_nested(struct mii_bus *bus, int addr, u16 page, u32 regnum, u16 val)
+{
+	int err;
+
+	mutex_lock_nested(&bus->mdio_lock, MDIO_MUTEX_NESTED);
+	err = __mdiobus_write_paged(bus, addr, page, regnum, val);
+	mutex_unlock(&bus->mdio_lock);
+
+	return err;
+}
+EXPORT_SYMBOL(mdiobus_write_paged_nested);
+
+/**
  * mdiobus_write - Convenience function for writing a given MII mgmt register
  * @bus: the mii_bus struct
  * @addr: the phy address
@@ -918,6 +1177,30 @@ int mdiobus_write(struct mii_bus *bus, i
 EXPORT_SYMBOL(mdiobus_write);
 
 /**
+ * mdiobus_write_paged - Convenience function for writing a given paged MII mgmt register
+ * @bus: the mii_bus struct
+ * @addr: the phy address
+ * @page: the register page to access
+ * @regnum: register number to write
+ * @val: value to write to @regnum
+ *
+ * NOTE: MUST NOT be called from interrupt context,
+ * because the bus read/write functions may wait for an interrupt
+ * to conclude the operation.
+ */
+int mdiobus_write_paged(struct mii_bus *bus, int addr, u16 page, u32 regnum, u16 val)
+{
+	int err;
+
+	mutex_lock(&bus->mdio_lock);
+	err = __mdiobus_write_paged(bus, addr, page, regnum, val);
+	mutex_unlock(&bus->mdio_lock);
+
+	return err;
+}
+EXPORT_SYMBOL(mdiobus_write_paged);
+
+/**
  * mdiobus_modify - Convenience function for modifying a given mdio device
  *	register
  * @bus: the mii_bus struct
@@ -939,6 +1222,51 @@ int mdiobus_modify(struct mii_bus *bus,
 EXPORT_SYMBOL_GPL(mdiobus_modify);
 
 /**
+ * mdiobus_modify_paged - Convenience function for modifying a given mdio device
+ *	register
+ * @bus: the mii_bus struct
+ * @addr: the phy address
+ * @page: the register page to access
+ * @regnum: register number to write
+ * @mask: bit mask of bits to clear
+ * @set: bit mask of bits to set
+ */
+int mdiobus_modify_paged(struct mii_bus *bus, int addr, u16 page, u32 regnum, u16 mask, u16 set)
+{
+	int err;
+
+	mutex_lock(&bus->mdio_lock);
+	err = __mdiobus_modify_changed_paged(bus, addr, page, regnum, mask, set);
+	mutex_unlock(&bus->mdio_lock);
+
+	return err < 0 ? err : 0;
+}
+EXPORT_SYMBOL_GPL(mdiobus_modify_paged);
+
+/**
+ * mdiobus_modify_changed_paged - Convenience function for modifying a given paged
+ * mdio device register and returning if it changed
+ * @bus: the mii_bus struct
+ * @addr: the phy address
+ * @page: the register page to access
+ * @regnum: register number to write
+ * @mask: bit mask of bits to clear
+ * @set: bit mask of bits to set
+ */
+int mdiobus_modify_changed_paged(struct mii_bus *bus, int addr, u16 page, u32 regnum,
+				 u16 mask, u16 set)
+{
+	int err;
+
+	mutex_lock(&bus->mdio_lock);
+	err = __mdiobus_modify_changed_paged(bus, addr, page, regnum, mask, set);
+	mutex_unlock(&bus->mdio_lock);
+
+	return err;
+}
+EXPORT_SYMBOL_GPL(mdiobus_modify_changed_paged);
+
+/**
  * mdio_bus_match - determine if given MDIO driver supports the given
  *		    MDIO device
  * @dev: target MDIO device
--- a/drivers/net/phy/phy-core.c
+++ b/drivers/net/phy/phy-core.c
@@ -481,10 +481,16 @@ int __phy_read_mmd(struct phy_device *ph
 		struct mii_bus *bus = phydev->mdio.bus;
 		int phy_addr = phydev->mdio.addr;
 
-		mmd_phy_indirect(bus, phy_addr, devad, regnum);
-
-		/* Read the content of the MMD's selected register */
-		val = __mdiobus_read(bus, phy_addr, MII_MMD_DATA);
+		if (bus->access_capabilities & MDIOBUS_ACCESS_C22_MMD) {
+			val = __mdiobus_c22_mmd_read(phydev->mdio.bus,
+						     phydev->mdio.addr,
+						     devad, regnum);
+		} else {
+			mmd_phy_indirect(bus, phy_addr, devad, regnum);
+
+			/* Read the content of the MMD's selected register */
+			val = __mdiobus_read(bus, phy_addr, MII_MMD_DATA);
+		}
 	}
 	return val;
 }
@@ -537,12 +543,18 @@ int __phy_write_mmd(struct phy_device *p
 		struct mii_bus *bus = phydev->mdio.bus;
 		int phy_addr = phydev->mdio.addr;
 
-		mmd_phy_indirect(bus, phy_addr, devad, regnum);
+		if (bus->access_capabilities & MDIOBUS_ACCESS_C22_MMD) {
+			ret = __mdiobus_c22_mmd_write(phydev->mdio.bus,
+						      phydev->mdio.addr,
+						      devad, regnum, val);
+		} else {
+			mmd_phy_indirect(bus, phy_addr, devad, regnum);
 
-		/* Write the data into MMD's selected register */
-		__mdiobus_write(bus, phy_addr, MII_MMD_DATA, val);
+			/* Write the data into MMD's selected register */
+			__mdiobus_write(bus, phy_addr, MII_MMD_DATA, val);
 
-		ret = 0;
+			ret = 0;
+		}
 	}
 	return ret;
 }
@@ -748,6 +760,13 @@ EXPORT_SYMBOL_GPL(phy_modify_mmd);
 
 static int __phy_read_page(struct phy_device *phydev)
 {
+	if (phydev->drv && phydev->drv->flags & PHY_HAS_REALTEK_PAGES) {
+		struct mii_bus *bus = phydev->mdio.bus;
+		int phy_addr = phydev->mdio.addr;
+
+		return bus->selected_page[phy_addr];
+	}
+
 	if (WARN_ONCE(!phydev->drv->read_page, "read_page callback not available, PHY driver not loaded?\n"))
 		return -EOPNOTSUPP;
 
@@ -756,6 +775,13 @@ static int __phy_read_page(struct phy_de
 
 static int __phy_write_page(struct phy_device *phydev, int page)
 {
+	if (phydev->drv && phydev->drv->flags & PHY_HAS_REALTEK_PAGES) {
+		struct mii_bus *bus = phydev->mdio.bus;
+		int phy_addr = phydev->mdio.addr;
+
+		return __mdiobus_select_page(bus, phy_addr, page);
+	}
+
 	if (WARN_ONCE(!phydev->drv->write_page, "write_page callback not available, PHY driver not loaded?\n"))
 		return -EOPNOTSUPP;
 
@@ -857,6 +883,18 @@ int phy_read_paged(struct phy_device *ph
 {
 	int ret = 0, oldpage;
 
+	if (phydev->drv && phydev->drv->flags & PHY_HAS_REALTEK_PAGES) {
+		struct mii_bus *bus = phydev->mdio.bus;
+		int phy_addr = phydev->mdio.addr;
+
+		if (bus->read_paged) {
+			phy_lock_mdio_bus(phydev);
+			ret = bus->read_paged(bus, phy_addr, page, regnum);
+			phy_unlock_mdio_bus(phydev);
+			return ret;
+		}
+	}
+
 	oldpage = phy_select_page(phydev, page);
 	if (oldpage >= 0)
 		ret = __phy_read(phydev, regnum);
@@ -878,6 +916,18 @@ int phy_write_paged(struct phy_device *p
 {
 	int ret = 0, oldpage;
 
+	if (phydev->drv && phydev->drv->flags & PHY_HAS_REALTEK_PAGES) {
+		struct mii_bus *bus = phydev->mdio.bus;
+		int phy_addr = phydev->mdio.addr;
+
+		if (bus->write_paged) {
+			phy_lock_mdio_bus(phydev);
+			ret = bus->write_paged(bus, phy_addr, page, regnum, val);
+			phy_unlock_mdio_bus(phydev);
+			return ret;
+		}
+	}
+
 	oldpage = phy_select_page(phydev, page);
 	if (oldpage >= 0)
 		ret = __phy_write(phydev, regnum, val);
--- a/include/linux/mdio.h
+++ b/include/linux/mdio.h
@@ -14,6 +14,7 @@
  * IEEE 802.3ae clause 45 addressing mode used by 10GIGE phy chips.
  */
 #define MII_ADDR_C45		(1<<30)
+#define MII_ADDR_C22_MMD	(1<<29)
 #define MII_DEVADDR_C45_SHIFT	16
 #define MII_DEVADDR_C45_MASK	GENMASK(20, 16)
 #define MII_REGADDR_C45_MASK	GENMASK(15, 0)
@@ -327,11 +328,19 @@ static inline void mii_10gbt_stat_mod_li
 			 advertising, lpa & MDIO_AN_10GBT_STAT_LP10G);
 }
 
+int __mdiobus_select_page(struct mii_bus *bus, int addr, u16 page);
 int __mdiobus_read(struct mii_bus *bus, int addr, u32 regnum);
 int __mdiobus_write(struct mii_bus *bus, int addr, u32 regnum, u16 val);
 int __mdiobus_modify_changed(struct mii_bus *bus, int addr, u32 regnum,
 			     u16 mask, u16 set);
 
+int __mdiobus_read_paged(struct mii_bus *bus, int addr, u16 page, u32 regnum);
+int __mdiobus_write_paged(struct mii_bus *bus, int addr, u16 page, u32 regnum, u16 val);
+int __mdiobus_modify_changed_paged(struct mii_bus *bus, int addr, u32 regnum, u16 page,
+				   u16 mask, u16 set);
+
+int mdiobus_select_page(struct mii_bus *bus, int addr, u16 page);
+int mdiobus_select_page_nested(struct mii_bus *bus, int addr, u16 page);
 int mdiobus_read(struct mii_bus *bus, int addr, u32 regnum);
 int mdiobus_read_nested(struct mii_bus *bus, int addr, u32 regnum);
 int mdiobus_write(struct mii_bus *bus, int addr, u32 regnum, u16 val);
@@ -339,11 +348,51 @@ int mdiobus_write_nested(struct mii_bus
 int mdiobus_modify(struct mii_bus *bus, int addr, u32 regnum, u16 mask,
 		   u16 set);
 
+int mdiobus_read_paged(struct mii_bus *bus, int addr, u16 page, u32 regnum);
+int mdiobus_read_nested_paged(struct mii_bus *bus, int addr, u16 page, u32 regnum);
+int mdiobus_write_paged(struct mii_bus *bus, int addr, u16 page, u32 regnum, u16 val);
+int mdiobus_write_nested_paged(struct mii_bus *bus, int addr, u16 page, u32 regnum, u16 val);
+int mdiobus_modify_paged(struct mii_bus *bus, int addr, u16 page, u32 regnum, u16 mask,
+			 u16 set);
+int mdiobus_modify_changed_paged(struct mii_bus *bus, int addr, u16 page, u32 regnum,
+				 u16 mask, u16 set);
+
+static inline int mdiodev_read_paged(struct mdio_device *mdiodev, u16 page,
+				     u32 regnum)
+{
+	return mdiobus_read_paged(mdiodev->bus, mdiodev->addr, page, regnum);
+}
+
+static inline int mdiodev_write_paged(struct mdio_device *mdiodev, u16 page,
+				      u32 regnum, u16 val)
+{
+	return mdiobus_write_paged(mdiodev->bus, mdiodev->addr, page, regnum, val);
+}
+
+static inline int mdiodev_modify_paged(struct mdio_device *mdiodev, u16 page,
+				       u32 regnum, u16 mask, u16 set)
+{
+	return mdiobus_modify_paged(mdiodev->bus, mdiodev->addr, page, regnum,
+				    mask, set);
+}
+
+static inline int mdiodev_modify_changed_paged(struct mdio_device *mdiodev, u16 page,
+					       u32 regnum, u16 mask, u16 set)
+{
+	return mdiobus_modify_changed_paged(mdiodev->bus, mdiodev->addr, page, regnum,
+					    mask, set);
+}
+
 static inline u32 mdiobus_c45_addr(int devad, u16 regnum)
 {
 	return MII_ADDR_C45 | devad << MII_DEVADDR_C45_SHIFT | regnum;
 }
 
+static inline u32 mdiobus_c22_mmd_addr(int devad, u16 regnum)
+{
+	return MII_ADDR_C22_MMD | devad << MII_DEVADDR_C45_SHIFT | regnum;
+}
+
 static inline u16 mdiobus_c45_regad(u32 regnum)
 {
 	return FIELD_GET(MII_REGADDR_C45_MASK, regnum);
@@ -367,6 +416,19 @@ static inline int __mdiobus_c45_write(st
 			       val);
 }
 
+static inline int __mdiobus_c22_mmd_read(struct mii_bus *bus, int prtad,
+					 int devad, u16 regnum)
+{
+	return __mdiobus_read(bus, prtad, mdiobus_c22_mmd_addr(devad, regnum));
+}
+
+static inline int __mdiobus_c22_mmd_write(struct mii_bus *bus, int prtad,
+					  int devad, u16 regnum, u16 val)
+{
+	return __mdiobus_write(bus, prtad, mdiobus_c22_mmd_addr(devad, regnum),
+			       val);
+}
+
 static inline int mdiobus_c45_read(struct mii_bus *bus, int prtad, int devad,
 				   u16 regnum)
 {
--- a/include/linux/phy.h
+++ b/include/linux/phy.h
@@ -80,6 +80,7 @@ extern const int phy_10gbit_features_arr
 #define PHY_IS_INTERNAL		0x00000001
 #define PHY_RST_AFTER_CLK_EN	0x00000002
 #define PHY_POLL_CABLE_TEST	0x00000004
+#define PHY_HAS_REALTEK_PAGES	0x00000010
 #define MDIO_DEVICE_IS_PHY	0x80000000
 
 /**
@@ -374,6 +375,22 @@ struct mii_bus {
 
 	/** @shared: shared state across different PHYs */
 	struct phy_package_shared *shared[PHY_MAX_ADDR];
+
+	/** @access_capabilities: hardware-assisted access capabilties */
+	enum {
+		MDIOBUS_ACCESS_SOFTWARE_ONLY = 0,
+		MDIOBUS_ACCESS_C22_MMD = 0x1,
+	} access_capabilities;
+
+	/** @read: Perform a read transfer on the bus, offloading page access */
+	int (*read_paged)(struct mii_bus *bus, int addr, u16 page, int regnum);
+	/** @write: Perform a write transfer on the bus, offloading page access */
+	int (*write_paged)(struct mii_bus *bus, int addr, u16 page, int regnum, u16 val);
+	/** currently selected page when page access is offloaded
+	 * array should be PHY_MAX_ADDR+1size, but current design of the MDIO driver
+	 * uses port addresses as phy addresses and they are up to 6 bit.
+	 */
+	u16 selected_page[64];
 };
 #define to_mii_bus(d) container_of(d, struct mii_bus, dev)
 
@@ -1651,6 +1668,66 @@ static inline int __phy_package_read(str
 	return __mdiobus_read(phydev->mdio.bus, shared->addr, regnum);
 }
 
+static inline int phy_package_read_port(struct phy_device *phydev, u16 port, u32 regnum)
+{
+	struct phy_package_shared *shared = phydev->shared;
+
+	if (!shared)
+		return -EIO;
+
+	return mdiobus_read(phydev->mdio.bus, shared->addr + port, regnum);
+}
+
+static inline int __phy_package_read_port(struct phy_device *phydev, u16 port, u32 regnum)
+{
+	struct phy_package_shared *shared = phydev->shared;
+
+	if (!shared)
+		return -EIO;
+
+	return __mdiobus_read(phydev->mdio.bus, shared->addr + port, regnum);
+}
+
+static inline int phy_package_read_paged(struct phy_device *phydev, u16 page, u32 regnum)
+{
+	struct phy_package_shared *shared = phydev->shared;
+
+	if (!shared)
+		return -EIO;
+
+	return mdiobus_read_paged(phydev->mdio.bus, shared->addr, page, regnum);
+}
+
+static inline int __phy_package_read_paged(struct phy_device *phydev, u16 page, u32 regnum)
+{
+	struct phy_package_shared *shared = phydev->shared;
+
+	if (!shared)
+		return -EIO;
+
+	return __mdiobus_read_paged(phydev->mdio.bus, shared->addr, page, regnum);
+}
+
+static inline int phy_package_port_read_paged(struct phy_device *phydev, u16 port, u16 page, u32 regnum)
+{
+	struct phy_package_shared *shared = phydev->shared;
+
+	if (!shared)
+		return -EIO;
+
+	return mdiobus_read_paged(phydev->mdio.bus, shared->addr + port, page, regnum);
+}
+
+static inline int __phy_package_port_read_paged(struct phy_device *phydev, u16 port, u16 page, u32 regnum)
+{
+	struct phy_package_shared *shared = phydev->shared;
+
+	if (!shared)
+		return -EIO;
+
+	return __mdiobus_read_paged(phydev->mdio.bus, shared->addr + port, page, regnum);
+}
+
 static inline int phy_package_write(struct phy_device *phydev,
 				    u32 regnum, u16 val)
 {
@@ -1673,6 +1750,72 @@ static inline int __phy_package_write(st
 	return __mdiobus_write(phydev->mdio.bus, shared->addr, regnum, val);
 }
 
+static inline int phy_package_port_write(struct phy_device *phydev,
+				         u16 port, u32 regnum, u16 val)
+{
+	struct phy_package_shared *shared = phydev->shared;
+
+	if (!shared)
+		return -EIO;
+
+	return mdiobus_write(phydev->mdio.bus, shared->addr + port, regnum, val);
+}
+
+static inline int __phy_package_port_write(struct phy_device *phydev,
+				      u16 port, u32 regnum, u16 val)
+{
+	struct phy_package_shared *shared = phydev->shared;
+
+	if (!shared)
+		return -EIO;
+
+	return __mdiobus_write(phydev->mdio.bus, shared->addr + port, regnum, val);
+}
+
+static inline int phy_package_port_write_paged(struct phy_device *phydev,
+					u16 port, u16 page, u32 regnum, u16 val)
+{
+	struct phy_package_shared *shared = phydev->shared;
+
+	if (!shared)
+		return -EIO;
+
+	return mdiobus_write_paged(phydev->mdio.bus, shared->addr + port, page, regnum, val);
+}
+
+static inline int __phy_package_port_write_paged(struct phy_device *phydev,
+					u16 port, u16 page, u32 regnum, u16 val)
+{
+	struct phy_package_shared *shared = phydev->shared;
+
+	if (!shared)
+		return -EIO;
+
+	return __mdiobus_write_paged(phydev->mdio.bus, shared->addr + port, page, regnum, val);
+}
+
+static inline int phy_package_write_paged(struct phy_device *phydev,
+					  u16 page, u32 regnum, u16 val)
+{
+	struct phy_package_shared *shared = phydev->shared;
+
+	if (!shared)
+		return -EIO;
+
+	return mdiobus_write_paged(phydev->mdio.bus, shared->addr, page, regnum, val);
+}
+
+static inline int __phy_package_write_paged(struct phy_device *phydev,
+					  u16 page, u32 regnum, u16 val)
+{
+	struct phy_package_shared *shared = phydev->shared;
+
+	if (!shared)
+		return -EIO;
+
+	return __mdiobus_write_paged(phydev->mdio.bus, shared->addr, page, regnum, val);
+}
+
 static inline bool __phy_package_set_once(struct phy_device *phydev,
 					  unsigned int b)
 {
--- a/include/uapi/linux/mii.h
+++ b/include/uapi/linux/mii.h
@@ -36,6 +36,7 @@
 #define MII_RESV2		0x1a	/* Reserved...                 */
 #define MII_TPISTATUS		0x1b	/* TPI status for 10mbps       */
 #define MII_NCONFIG		0x1c	/* Network interface config    */
+#define MII_MAINPAGE		0x1f	/* Page register               */
 
 /* Basic mode control register. */
 #define BMCR_RESV		0x003f	/* Unused...                   */
