From 97678827eeb16cb5c5bc5a2d9389e37191cb54b7 Mon Sep 17 00:00:00 2001
From: Russell King <rmk+kernel@armlinux.org.uk>
Date: Fri, 29 Nov 2019 00:31:03 +0000
Subject: net: phy: add helpers for comparing phy IDs

There are several places which open code comparing PHY IDs. Provide a
couple of helpers to assist with this, using a slightly simpler test
than the original:

- phy_id_compare() compares two arbitary PHY IDs and a mask of the
  significant bits in the ID.
- phydev_id_compare() compares the bound phydev with the specified
  PHY ID, using the bound driver's mask.

Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
---
 drivers/net/phy/phy_device.c | 16 +++++++---------
 drivers/net/phy/phylink.c    |  4 ++--
 include/linux/phy.h          | 28 ++++++++++++++++++++++++++++
 3 files changed, 37 insertions(+), 11 deletions(-)

diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
index d340eb2f9469..5779ea2fb0d3 100644
--- a/drivers/net/phy/phy_device.c
+++ b/drivers/net/phy/phy_device.c
@@ -388,8 +388,7 @@ int phy_unregister_fixup(const char *bus_id, u32 phy_uid, u32 phy_uid_mask)
 		fixup = list_entry(pos, struct phy_fixup, list);
 
 		if ((!strcmp(fixup->bus_id, bus_id)) &&
-		    ((fixup->phy_uid & phy_uid_mask) ==
-		     (phy_uid & phy_uid_mask))) {
+		    phy_id_compare(fixup->phy_uid, phy_uid, phy_uid_mask)) {
 			list_del(&fixup->list);
 			kfree(fixup);
 			ret = 0;
@@ -425,8 +424,8 @@ static int phy_needs_fixup(struct phy_device *phydev, struct phy_fixup *fixup)
 		if (strcmp(fixup->bus_id, PHY_ANY_ID) != 0)
 			return 0;
 
-	if ((fixup->phy_uid & fixup->phy_uid_mask) !=
-	    (phydev->phy_id & fixup->phy_uid_mask))
+	if (!phy_id_compare(phydev->phy_id, fixup->phy_uid,
+			    fixup->phy_uid_mask))
 		if (fixup->phy_uid != PHY_ANY_UID)
 			return 0;
 
@@ -473,15 +472,14 @@ static int phy_bus_match(struct device *dev, struct device_driver *drv)
 			if (phydev->c45_ids.device_ids[i] == 0xffffffff)
 				continue;
 
-			if ((phydrv->phy_id & phydrv->phy_id_mask) ==
-			    (phydev->c45_ids.device_ids[i] &
-			     phydrv->phy_id_mask))
+			if (phy_id_compare(phydev->c45_ids.device_ids[i],
+					   phydrv->phy_id, phydrv->phy_id_mask))
 				return 1;
 		}
 		return 0;
 	} else {
-		return (phydrv->phy_id & phydrv->phy_id_mask) ==
-			(phydev->phy_id & phydrv->phy_id_mask);
+		return phy_id_compare(phydev->phy_id, phydrv->phy_id,
+				      phydrv->phy_id_mask);
 	}
 }
 
diff --git a/drivers/net/phy/phylink.c b/drivers/net/phy/phylink.c
index e721ffa87bcc..6e66aa1d3a7e 100644
--- a/drivers/net/phy/phylink.c
+++ b/drivers/net/phy/phylink.c
@@ -2908,8 +2908,8 @@ static void phylink_sfp_link_up(void *upstream)
  */
 static bool phylink_phy_no_inband(struct phy_device *phy)
 {
-	return phy->is_c45 &&
-		(phy->c45_ids.device_ids[1] & 0xfffffff0) == 0xae025150;
+	return phy->is_c45 && phy_id_compare(phy->c45_ids.device_ids[1],
+					     0xae025150, 0xfffffff0);
 }
 
 static int phylink_sfp_connect_phy(void *upstream, struct phy_device *phy)
diff --git a/include/linux/phy.h b/include/linux/phy.h
index 36ca2b5c2253..1f74a6414a90 100644
--- a/include/linux/phy.h
+++ b/include/linux/phy.h
@@ -943,6 +943,34 @@ struct phy_driver {
 #define PHY_ID_MATCH_MODEL(id) .phy_id = (id), .phy_id_mask = GENMASK(31, 4)
 #define PHY_ID_MATCH_VENDOR(id) .phy_id = (id), .phy_id_mask = GENMASK(31, 10)
 
+/**
+ * phy_id_compare - compare @id1 with @id2 taking account of @mask
+ * @id1: first PHY ID
+ * @id2: second PHY ID
+ * @mask: the PHY ID mask, set bits are significant in matching
+ *
+ * Return true if the bits from @id1 and @id2 specified by @mask match.
+ * This uses an equivalent test to (@id & @mask) == (@phy_id & @mask).
+ */
+static inline bool phy_id_compare(u32 id1, u32 id2, u32 mask)
+{
+	return !((id1 ^ id2) & mask);
+}
+
+/**
+ * phydev_id_compare - compare @id with the PHY's Clause 22 ID
+ * @phydev: the PHY device
+ * @id: the PHY ID to be matched
+ *
+ * Compare the @phydev clause 22 ID with the provided @id and return true or
+ * false depending whether it matches, using the bound driver mask. The
+ * @phydev must be bound to a driver.
+ */
+static inline bool phydev_id_compare(struct phy_device *phydev, u32 id)
+{
+	return phy_id_compare(id, phydev->phy_id, phydev->drv->phy_id_mask);
+}
+
 /* A Structure for boards to register fixups with the PHY Lib */
 struct phy_fixup {
 	struct list_head list;
-- 
cgit