Re: [PATCH net-next v2] net: phy: Add driver for Motorcomm yt8531 gigabit ethernet phy

on Dec. 3, 2022, 8:47 p.m. UTC , Andrew Lunn wrote:

On Fri, Dec 02, 2022 at 01:34:16PM +0000, Russell King (Oracle) wrote:

quoted

On Fri, Dec 02, 2022 at 02:27:43PM +0100, Andrew Lunn wrote:

quoted

quoted

+static bool mdio_is_locked(struct phy_device *phydev)
+{
+	return mutex_is_locked(&phydev->mdio.bus->mdio_lock);
+}
+
+#define ASSERT_MDIO(phydev) \
+	WARN_ONCE(!mdio_is_locked(phydev), \
+		  "MDIO: assertion failed at %s (%d)\n", __FILE__,  __LINE__)
+

Hi Frank

You are not the only one who gets locking wrong. This could be used in
other drivers. Please add it to include/linux/phy.h,

That placement doesn't make much sense.

As I already said, we have lockdep checks in drivers/net/phy/mdio_bus.c,
and if we want to increase their effectiveness, then that's the place
that it should be done.

I was following the ASSERT_RTNL model, but that is used in quite deep
and complex call stacks, and it is useful to scatter the macro in lots
of places. PHY drivers are however very shallow, so yes, putting them
in mdio_bus.c makes a lot of sense.

quoted

I don't see any point in using __FILE__ and __LINE__ in the above
macro either. Firstly, WARN_ONCE() already includes the file and line,
and secondly, the backtrace is more useful than the file and line where
the assertion occurs especially if it's placed in mdio_bus.c

And PHY driver functions are simpler, there is a lot less inlining
going on, so the function name is probably all you need to know to
find where you messed up the locking. So i agree, they can be removed.

     Andrew

 Hi Andrew and Russell, Thanks!
 
 change the mdio_bus.c like follow ok?
 
 -add "ASSERT_MDIO"
 -add "ASSERT_MDIO(bus);" in __mdiobus_read and __mdiobus_write function 
 
 
 static inline bool mdiobus_is_locked(struct mii_bus *bus)
{
	return mutex_is_locked(&bus->mdio_lock);
}

#define ASSERT_MDIO(bus) \
	WARN_ONCE(!mdiobus_is_locked(bus), \
		  "MDIO: assertion failed\n")
		  
 int __mdiobus_read(struct mii_bus *bus, int addr, u32 regnum)
{
	int retval;

	ASSERT_MDIO(bus);
	lockdep_assert_held_once(&bus->mdio_lock);

	retval = bus->read(bus, addr, regnum);
...
}

 int __mdiobus_write(struct mii_bus *bus, int addr, u32 regnum, u16 val)
{
	int err;

	ASSERT_MDIO(bus);
	lockdep_assert_held_once(&bus->mdio_lock);

	err = bus->write(bus, addr, regnum, val);
...
}


on Dec. 2, 2022, 1:27 p.m. UTC , Andrew Lunn wrote:

quoted

 /**
  * ytphy_read_ext() - read a PHY's extended register
  * @phydev: a pointer to a &struct phy_device

@@ -258,6 +271,8 @@ static int ytphy_read_ext(struct phy_device *phydev, u16 regnum)
 {
 	int ret;
 
+	ASSERT_MDIO(phydev);
+
 	ret = __phy_write(phydev, YTPHY_PAGE_SELECT, regnum);
 	if (ret < 0)
 		return ret;

@@ -297,6 +312,8 @@ static int ytphy_write_ext(struct phy_device *phydev, u16 regnum, u16 val)
 {
 	int ret;
 
+	ASSERT_MDIO(phydev);
+
 	ret = __phy_write(phydev, YTPHY_PAGE_SELECT, regnum);
 	if (ret < 0)
 		return ret;

@@ -342,6 +359,8 @@ static int ytphy_modify_ext(struct phy_device *phydev, u16 regnum, u16 mask,
 {
 	int ret;
 
+	ASSERT_MDIO(phydev);
+
 	ret = __phy_write(phydev, YTPHY_PAGE_SELECT, regnum);
 	if (ret < 0)
 		return ret;

@@ -479,6 +498,76 @@ static int ytphy_set_wol(struct phy_device *phydev, struct ethtool_wolinfo *wol)
 	return phy_restore_page(phydev, old_page, ret);
 }

Please make the above one patch, which adds the macro and its
users. There are a couple more below as well.

Did it find any problems in the current code? Any fixes mixed
in here?

Then add yt8531 is another patch.

 Thanks! 
 It not find any problems in the current code. 
 ASSERT_MDIO in motorcomm.c will be removed. 
 

quoted

+/**
+ * yt8531_set_wol() - turn wake-on-lan on or off
+ * @phydev: a pointer to a &struct phy_device
+ * @wol: a pointer to a &struct ethtool_wolinfo
+ *
+ * returns 0 or negative errno code
+ */
+static int yt8531_set_wol(struct phy_device *phydev,
+			  struct ethtool_wolinfo *wol)
+{
+	struct net_device *p_attached_dev;
+	const u16 mac_addr_reg[] = {
+		YTPHY_WOL_MACADDR2_REG,
+		YTPHY_WOL_MACADDR1_REG,
+		YTPHY_WOL_MACADDR0_REG,
+	};
+	const u8 *mac_addr;
+	u16 mask;
+	u16 val;
+	int ret;
+	u8 i;
+
+	if (wol->wolopts & WAKE_MAGIC) {
+		p_attached_dev = phydev->attached_dev;
+		if (!p_attached_dev)
+			return -ENODEV;
+
+		mac_addr = (const u8 *)p_attached_dev->dev_addr;

Why the cast?

 I'm sorry. What does "Why the cast?" mean?
 

quoted

+		if (!is_valid_ether_addr(mac_addr))
+			return -EINVAL;

  Andrew