diff mbox series

[RFC,net-next,v2,10/12] net: mdio: add mdiobus_c45_read/write_nested helpers

Message ID 20221227-v6-2-rc1-c45-seperation-v2-10-ddb37710e5a7@walle.cc (mailing list archive)
State Superseded
Delegated to: Netdev Maintainers
Headers show
Series net: mdio: Start separating C22 and C45 | 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 fail Errors and warnings before: 579 this patch: 579
netdev/cc_maintainers success CCed 11 of 11 maintainers
netdev/build_clang fail Errors and warnings before: 303 this patch: 303
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 fail Errors and warnings before: 547 this patch: 547
netdev/checkpatch warning CHECK: Alignment should match open parenthesis
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Michael Walle Dec. 27, 2022, 11:07 p.m. UTC 
From: Andrew Lunn <andrew@lunn.ch>

Some DSA devices pass through PHY access to the MDIO bus the switch is
on. Add C45 versions of the current C22 helpers for nested accesses to
MDIO busses, so that C22 and C45 can be separated in these DSA
drivers.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Michael Walle <michael@walle.cc>
---
v2:
 - [al] new patch
---
 drivers/net/phy/mdio_bus.c | 55 ++++++++++++++++++++++++++++++++++++++++++++++
 include/linux/mdio.h       |  4 ++++
 2 files changed, 59 insertions(+)
diff mbox series

Patch

diff --git a/drivers/net/phy/mdio_bus.c b/drivers/net/phy/mdio_bus.c
index 0b04ce3766c8..7f6b12b65f0d 100644
--- a/drivers/net/phy/mdio_bus.c
+++ b/drivers/net/phy/mdio_bus.c
@@ -1011,6 +1011,33 @@  int mdiobus_c45_read(struct mii_bus *bus, int addr, int devad, u32 regnum)
 }
 EXPORT_SYMBOL(mdiobus_c45_read);
 
+/**
+ * mdiobus_c45_read_nested - Nested version of the mdiobus_c45_read function
+ * @bus: the mii_bus struct
+ * @addr: the phy address
+ * @devad: device address to read
+ * @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_c45_read_nested(struct mii_bus *bus, int addr, int devad,
+			    u32 regnum)
+{
+	int retval;
+
+	mutex_lock_nested(&bus->mdio_lock, MDIO_MUTEX_NESTED);
+	retval = __mdiobus_c45_read(bus, addr, devad, regnum);
+	mutex_unlock(&bus->mdio_lock);
+
+	return retval;
+}
+EXPORT_SYMBOL(mdiobus_c45_read_nested);
+
 /**
  * mdiobus_write_nested - Nested version of the mdiobus_write function
  * @bus: the mii_bus struct
@@ -1085,6 +1112,34 @@  int mdiobus_c45_write(struct mii_bus *bus, int addr, int devad, u32 regnum,
 }
 EXPORT_SYMBOL(mdiobus_c45_write);
 
+/**
+ * mdiobus_c45_write_nested - Nested version of the mdiobus_c45_write function
+ * @bus: the mii_bus struct
+ * @addr: the phy address
+ * @devad: device address to read
+ * @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_c45_write_nested(struct mii_bus *bus, int addr, int devad,
+			     u32 regnum, u16 val)
+{
+	int err;
+
+	mutex_lock_nested(&bus->mdio_lock, MDIO_MUTEX_NESTED);
+	err = __mdiobus_c45_write(bus, addr, devad, regnum, val);
+	mutex_unlock(&bus->mdio_lock);
+
+	return err;
+}
+EXPORT_SYMBOL(mdiobus_c45_write_nested);
+
 /**
  * mdiobus_modify - Convenience function for modifying a given mdio device
  *	register
diff --git a/include/linux/mdio.h b/include/linux/mdio.h
index 97b49765e8b5..220f3ca8702d 100644
--- a/include/linux/mdio.h
+++ b/include/linux/mdio.h
@@ -425,10 +425,14 @@  int mdiobus_modify_changed(struct mii_bus *bus, int addr, u32 regnum,
 			   u16 mask, u16 set);
 int __mdiobus_c45_read(struct mii_bus *bus, int addr, int devad, u32 regnum);
 int mdiobus_c45_read(struct mii_bus *bus, int addr, int devad, u32 regnum);
+int mdiobus_c45_read_nested(struct mii_bus *bus, int addr, int devad,
+			     u32 regnum);
 int __mdiobus_c45_write(struct mii_bus *bus, int addr,  int devad, u32 regnum,
 			u16 val);
 int mdiobus_c45_write(struct mii_bus *bus, int addr,  int devad, u32 regnum,
 		      u16 val);
+int mdiobus_c45_write_nested(struct mii_bus *bus, int addr,  int devad,
+			     u32 regnum, u16 val);
 int mdiobus_c45_modify(struct mii_bus *bus, int addr, int devad, u32 regnum,
 		       u16 mask, u16 set);