[openwrt/openwrt] ramips: backport unlocked mdiobus accessors

[LEDE Commits]

blocktrron pushed a commit to openwrt/openwrt.git, branch openwrt-19.07:
https://git.openwrt.org/08ef2073d416214a0f7edf02aefa32d4107e4c1c

commit 08ef2073d416214a0f7edf02aefa32d4107e4c1c
Author: David Bauer <mail at david-bauer.net>
AuthorDate: Mon May 3 00:08:38 2021 +0200

    ramips: backport unlocked mdiobus accessors
    
    Commit 718e97c5c843 ("ramips: mt7530 swconfig: fix race condition in
    register access") backports a fix which depends on unlocked MMD
    accessors, however these were not yet included in Kernel 4.14 and they
    were not backported yet.
    
    Fixes commit 718e97c5c843 ("ramips: mt7530 swconfig: fix race condition in register access")
    
    Signed-off-by: David Bauer <mail at david-bauer.net>
---
 .../700-net-mdiobus-add-unlocked-accessors.patch   | 141 +++++++++++++++++++++
 1 file changed, 141 insertions(+)

diff --git a/target/linux/ramips/patches-4.14/700-net-mdiobus-add-unlocked-accessors.patch b/target/linux/ramips/patches-4.14/700-net-mdiobus-add-unlocked-accessors.patch
new file mode 100644
index 0000000000..4880c49b13
--- /dev/null
+++ b/target/linux/ramips/patches-4.14/700-net-mdiobus-add-unlocked-accessors.patch
@@ -0,0 +1,141 @@
+From b2b8b06f18281c637da274b18e330bc52351637e Mon Sep 17 00:00:00 2001
+From: Russell King <rmk+kernel at armlinux.org.uk>
+Date: Tue, 2 Jan 2018 10:58:27 +0000
+Subject: [PATCH] net: mdiobus: add unlocked accessors
+
+commit 34dc08e4be208539b7c4aa8154a610e1736705e8 upstream.
+
+Add unlocked versions of the bus accessors, which allows access to the
+bus with all the tracing. These accessors validate that the bus mutex
+is held, which is a basic requirement for all mii bus accesses.
+
+Reviewed-by: Florian Fainelli <f.fainelli at gmail.com>
+Signed-off-by: Russell King <rmk+kernel at armlinux.org.uk>
+Signed-off-by: David S. Miller <davem at davemloft.net>
+---
+ drivers/net/phy/mdio_bus.c | 65 +++++++++++++++++++++++++++++++-------
+ include/linux/mdio.h       |  3 ++
+ 2 files changed, 56 insertions(+), 12 deletions(-)
+
+--- a/drivers/net/phy/mdio_bus.c
++++ b/drivers/net/phy/mdio_bus.c
+@@ -493,6 +493,55 @@ struct phy_device *mdiobus_scan(struct m
+ EXPORT_SYMBOL(mdiobus_scan);
+ 
+ /**
++ * __mdiobus_read - Unlocked version of the mdiobus_read function
++ * @bus: the mii_bus struct
++ * @addr: the phy address
++ * @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(struct mii_bus *bus, int addr, u32 regnum)
++{
++	int retval;
++
++	WARN_ON_ONCE(!mutex_is_locked(&bus->mdio_lock));
++
++	retval = bus->read(bus, addr, regnum);
++
++	trace_mdio_access(bus, 1, addr, regnum, retval, retval);
++
++	return retval;
++}
++EXPORT_SYMBOL(__mdiobus_read);
++
++/**
++ * __mdiobus_write - Unlocked version of the mdiobus_write function
++ * @bus: the mii_bus struct
++ * @addr: the phy address
++ * @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(struct mii_bus *bus, int addr, u32 regnum, u16 val)
++{
++	int err;
++
++	WARN_ON_ONCE(!mutex_is_locked(&bus->mdio_lock));
++
++	err = bus->write(bus, addr, regnum, val);
++
++	trace_mdio_access(bus, 0, addr, regnum, val, err);
++
++	return err;
++}
++EXPORT_SYMBOL(__mdiobus_write);
++
++/**
+  * mdiobus_read_nested - Nested version of the mdiobus_read function
+  * @bus: the mii_bus struct
+  * @addr: the phy address
+@@ -512,11 +561,9 @@ int mdiobus_read_nested(struct mii_bus *
+ 	BUG_ON(in_interrupt());
+ 
+ 	mutex_lock_nested(&bus->mdio_lock, MDIO_MUTEX_NESTED);
+-	retval = bus->read(bus, addr, regnum);
++	retval = __mdiobus_read(bus, addr, regnum);
+ 	mutex_unlock(&bus->mdio_lock);
+ 
+-	trace_mdio_access(bus, 1, addr, regnum, retval, retval);
+-
+ 	return retval;
+ }
+ EXPORT_SYMBOL(mdiobus_read_nested);
+@@ -538,11 +585,9 @@ int mdiobus_read(struct mii_bus *bus, in
+ 	BUG_ON(in_interrupt());
+ 
+ 	mutex_lock(&bus->mdio_lock);
+-	retval = bus->read(bus, addr, regnum);
++	retval = __mdiobus_read(bus, addr, regnum);
+ 	mutex_unlock(&bus->mdio_lock);
+ 
+-	trace_mdio_access(bus, 1, addr, regnum, retval, retval);
+-
+ 	return retval;
+ }
+ EXPORT_SYMBOL(mdiobus_read);
+@@ -568,11 +613,9 @@ int mdiobus_write_nested(struct mii_bus
+ 	BUG_ON(in_interrupt());
+ 
+ 	mutex_lock_nested(&bus->mdio_lock, MDIO_MUTEX_NESTED);
+-	err = bus->write(bus, addr, regnum, val);
++	err = __mdiobus_write(bus, addr, regnum, val);
+ 	mutex_unlock(&bus->mdio_lock);
+ 
+-	trace_mdio_access(bus, 0, addr, regnum, val, err);
+-
+ 	return err;
+ }
+ EXPORT_SYMBOL(mdiobus_write_nested);
+@@ -595,11 +638,9 @@ int mdiobus_write(struct mii_bus *bus, i
+ 	BUG_ON(in_interrupt());
+ 
+ 	mutex_lock(&bus->mdio_lock);
+-	err = bus->write(bus, addr, regnum, val);
++	err = __mdiobus_write(bus, addr, regnum, val);
+ 	mutex_unlock(&bus->mdio_lock);
+ 
+-	trace_mdio_access(bus, 0, addr, regnum, val, err);
+-
+ 	return err;
+ }
+ EXPORT_SYMBOL(mdiobus_write);
+--- a/include/linux/mdio.h
++++ b/include/linux/mdio.h
+@@ -257,6 +257,9 @@ static inline u16 ethtool_adv_to_mmd_eee
+ 	return reg;
+ }
+ 
++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_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);