Merge branch 'libphy_mmd'

Vince Bridgers says:

====================
net: libphy: Add phy specific functions to access mmd regs

This set of patches addresses a problem found with the Micrel ksz9021 phy and
libphy, where the ksz9021 phy does not support mmd extended register access
per the IEEE specification as assumed by libphy. The first patch adds a
framework for phy specific support to specify their own function to access
extended phy registers, return a failure code if not supported, or to default
to libphy's IEEE defined method for accessing the mmd extended phy registers.

This issue was found by using the Synopsys EMAC and a Micrel ksz9021 phy on the
Altera Cyclone 5 SOC development kit. This patch was tested on the same system
in both positive and negative test cases.

V5: Revert name of mmd register access functions, check for phy specific
    driver override functions in mmd register access functions per
    Florian's comments to minimize source code changes
V4: Correct error when formatting V3 patch - erroneous text cut from code
V3: Correct formatting of function arguments, remove return statement from
    NULL functions, and add patch for PHY driver documentation per review
    comments.
V2: Split the original patch submission into seperate patches for the libphy
    framework required for the modification and for the Micrel Phy.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

4 files changed, 95 insertions, 24 deletions

diff --git a/Documentation/networking/phy.txt b/Documentation/networking/phy.txt
index 3544c98401fd..e839e7efc835 100644
--- a/Documentation/networking/phy.txt
+++ b/Documentation/networking/phy.txt
@@ -272,6 +272,8 @@ Writing a PHY driver
    txtsamp: Requests a transmit timestamp at the PHY level for a 'skb'
    set_wol: Enable Wake-on-LAN at the PHY level
    get_wol: Get the Wake-on-LAN status at the PHY level
+   read_mmd_indirect: Read PHY MMD indirect register
+   write_mmd_indirect: Write PHY MMD indirect register
 
  Of these, only config_aneg and read_status are required to be
  assigned by the driver code.  The rest are optional.  Also, it is
@@ -284,7 +286,21 @@ Writing a PHY driver
 
  Feel free to look at the Marvell, Cicada, and Davicom drivers in
  drivers/net/phy/ for examples (the lxt and qsemi drivers have
- not been tested as of this writing)
+ not been tested as of this writing).
+
+ The PHY's MMD register accesses are handled by the PAL framework
+ by default, but can be overridden by a specific PHY driver if
+ required. This could be the case if a PHY was released for
+ manufacturing before the MMD PHY register definitions were
+ standardized by the IEEE. Most modern PHYs will be able to use
+ the generic PAL framework for accessing the PHY's MMD registers.
+ An example of such usage is for Energy Efficient Ethernet support,
+ implemented in the PAL. This support uses the PAL to access MMD
+ registers for EEE query and configuration if the PHY supports
+ the IEEE standard access mechanisms, or can use the PHY's specific
+ access interfaces if overridden by the specific PHY driver. See
+ the Micrel driver in drivers/net/phy/ for an example of how this
+ can be implemented.
 
 Board Fixups
 
diff --git a/drivers/net/phy/micrel.c b/drivers/net/phy/micrel.c
index bc7c7d2f75f2..fd0ea7c50ee6 100644
--- a/drivers/net/phy/micrel.c
+++ b/drivers/net/phy/micrel.c
@@ -420,6 +420,26 @@ static int ksz8873mll_config_aneg(struct phy_device *phydev)
         return 0;
 }
 
+/* This routine returns -1 as an indication to the caller that the
+ * Micrel ksz9021 10/100/1000 PHY does not support standard IEEE
+ * MMD extended PHY registers.
+ */
+static int
+ksz9021_rd_mmd_phyreg(struct phy_device *phydev, int ptrad, int devnum,
+                      int regnum)
+{
+        return -1;
+}
+
+/* This routine does nothing since the Micrel ksz9021 does not support
+ * standard IEEE MMD extended PHY registers.
+ */
+static void
+ksz9021_wr_mmd_phyreg(struct phy_device *phydev, int ptrad, int devnum,
+                      int regnum, u32 val)
+{
+}
+
 static struct phy_driver ksphy_driver[] = {
 {
         .phy_id         = PHY_ID_KS8737,
@@ -565,6 +585,8 @@ static struct phy_driver ksphy_driver[] = {
         .config_intr    = ksz9021_config_intr,
         .suspend        = genphy_suspend,
         .resume         = genphy_resume,
+        .read_mmd_indirect = ksz9021_rd_mmd_phyreg,
+        .write_mmd_indirect = ksz9021_wr_mmd_phyreg,
         .driver         = { .owner = THIS_MODULE, },
 }, {
         .phy_id         = PHY_ID_KSZ9031,
diff --git a/drivers/net/phy/phy.c b/drivers/net/phy/phy.c
index e56e269a6eb3..c94e2a27446a 100644
--- a/drivers/net/phy/phy.c
+++ b/drivers/net/phy/phy.c
@@ -942,7 +942,7 @@ static inline void mmd_phy_indirect(struct mii_bus *bus, int prtad, int devad,
 
 /**
  * phy_read_mmd_indirect - reads data from the MMD registers
- * @bus: the target MII bus
+ * @phydev: The PHY device bus
  * @prtad: MMD Address
  * @devad: MMD DEVAD
  * @addr: PHY address on the MII bus
@@ -955,18 +955,26 @@ static inline void mmd_phy_indirect(struct mii_bus *bus, int prtad, int devad,
  * 3) Write reg 13 // MMD Data Command for MMD DEVAD
  * 3) Read  reg 14 // Read MMD data
  */
-static int phy_read_mmd_indirect(struct mii_bus *bus, int prtad, int devad,
-                                 int addr)
+static int phy_read_mmd_indirect(struct phy_device *phydev, int prtad,
+                                 int devad, int addr)
 {
-        mmd_phy_indirect(bus, prtad, devad, addr);
+        struct phy_driver *phydrv = phydev->drv;
+        int value = -1;
 
-        /* Read the content of the MMD's selected register */
-        return bus->read(bus, addr, MII_MMD_DATA);
+        if (phydrv->read_mmd_indirect == NULL) {
+                mmd_phy_indirect(phydev->bus, prtad, devad, addr);
+
+                /* Read the content of the MMD's selected register */
+                value = phydev->bus->read(phydev->bus, addr, MII_MMD_DATA);
+        } else {
+                value = phydrv->read_mmd_indirect(phydev, prtad, devad, addr);
+        }
+        return value;
 }
 
 /**
  * phy_write_mmd_indirect - writes data to the MMD registers
- * @bus: the target MII bus
+ * @phydev: The PHY device
  * @prtad: MMD Address
  * @devad: MMD DEVAD
  * @addr: PHY address on the MII bus
@@ -980,13 +988,19 @@ static int phy_read_mmd_indirect(struct mii_bus *bus, int prtad, int devad,
  * 3) Write reg 13 // MMD Data Command for MMD DEVAD
  * 3) Write reg 14 // Write MMD data
  */
-static void phy_write_mmd_indirect(struct mii_bus *bus, int prtad, int devad,
-                                   int addr, u32 data)
+static void phy_write_mmd_indirect(struct phy_device *phydev, int prtad,
+                                   int devad, int addr, u32 data)
 {
-        mmd_phy_indirect(bus, prtad, devad, addr);
+        struct phy_driver *phydrv = phydev->drv;
 
-        /* Write the data into MMD's selected register */
-        bus->write(bus, addr, MII_MMD_DATA, data);
+        if (phydrv->write_mmd_indirect == NULL) {
+                mmd_phy_indirect(phydev->bus, prtad, devad, addr);
+
+                /* Write the data into MMD's selected register */
+                phydev->bus->write(phydev->bus, addr, MII_MMD_DATA, data);
+        } else {
+                phydrv->write_mmd_indirect(phydev, prtad, devad, addr, data);
+        }
 }
 
 /**
@@ -1020,7 +1034,7 @@ int phy_init_eee(struct phy_device *phydev, bool clk_stop_enable)
                         return status;
 
                 /* First check if the EEE ability is supported */
-                eee_cap = phy_read_mmd_indirect(phydev->bus, MDIO_PCS_EEE_ABLE,
+                eee_cap = phy_read_mmd_indirect(phydev, MDIO_PCS_EEE_ABLE,
                                                 MDIO_MMD_PCS, phydev->addr);
                 if (eee_cap < 0)
                         return eee_cap;
@@ -1032,12 +1046,12 @@ int phy_init_eee(struct phy_device *phydev, bool clk_stop_enable)
                 /* Check which link settings negotiated and verify it in
                  * the EEE advertising registers.
                  */
-                eee_lp = phy_read_mmd_indirect(phydev->bus, MDIO_AN_EEE_LPABLE,
+                eee_lp = phy_read_mmd_indirect(phydev, MDIO_AN_EEE_LPABLE,
                                                MDIO_MMD_AN, phydev->addr);
                 if (eee_lp < 0)
                         return eee_lp;
 
-                eee_adv = phy_read_mmd_indirect(phydev->bus, MDIO_AN_EEE_ADV,
+                eee_adv = phy_read_mmd_indirect(phydev, MDIO_AN_EEE_ADV,
                                                 MDIO_MMD_AN, phydev->addr);
                 if (eee_adv < 0)
                         return eee_adv;
@@ -1052,15 +1066,16 @@ int phy_init_eee(struct phy_device *phydev, bool clk_stop_enable)
                         /* Configure the PHY to stop receiving xMII
                          * clock while it is signaling LPI.
                          */
-                        int val = phy_read_mmd_indirect(phydev->bus, MDIO_CTRL1,
+                        int val = phy_read_mmd_indirect(phydev, MDIO_CTRL1,
                                                         MDIO_MMD_PCS,
                                                         phydev->addr);
                         if (val < 0)
                                 return val;
 
                         val |= MDIO_PCS_CTRL1_CLKSTOP_EN;
-                        phy_write_mmd_indirect(phydev->bus, MDIO_CTRL1,
-                                               MDIO_MMD_PCS, phydev->addr, val);
+                        phy_write_mmd_indirect(phydev, MDIO_CTRL1,
+                                               MDIO_MMD_PCS, phydev->addr,
+                                               val);
                 }
 
                 return 0; /* EEE supported */
@@ -1079,7 +1094,7 @@ EXPORT_SYMBOL(phy_init_eee);
  */
 int phy_get_eee_err(struct phy_device *phydev)
 {
-        return phy_read_mmd_indirect(phydev->bus, MDIO_PCS_EEE_WK_ERR,
+        return phy_read_mmd_indirect(phydev, MDIO_PCS_EEE_WK_ERR,
                                      MDIO_MMD_PCS, phydev->addr);
 }
 EXPORT_SYMBOL(phy_get_eee_err);
@@ -1097,21 +1112,21 @@ int phy_ethtool_get_eee(struct phy_device *phydev, struct ethtool_eee *data)
         int val;
 
         /* Get Supported EEE */
-        val = phy_read_mmd_indirect(phydev->bus, MDIO_PCS_EEE_ABLE,
+        val = phy_read_mmd_indirect(phydev, MDIO_PCS_EEE_ABLE,
                                     MDIO_MMD_PCS, phydev->addr);
         if (val < 0)
                 return val;
         data->supported = mmd_eee_cap_to_ethtool_sup_t(val);
 
         /* Get advertisement EEE */
-        val = phy_read_mmd_indirect(phydev->bus, MDIO_AN_EEE_ADV,
+        val = phy_read_mmd_indirect(phydev, MDIO_AN_EEE_ADV,
                                     MDIO_MMD_AN, phydev->addr);
         if (val < 0)
                 return val;
         data->advertised = mmd_eee_adv_to_ethtool_adv_t(val);
 
         /* Get LP advertisement EEE */
-        val = phy_read_mmd_indirect(phydev->bus, MDIO_AN_EEE_LPABLE,
+        val = phy_read_mmd_indirect(phydev, MDIO_AN_EEE_LPABLE,
                                     MDIO_MMD_AN, phydev->addr);
         if (val < 0)
                 return val;
@@ -1132,7 +1147,7 @@ int phy_ethtool_set_eee(struct phy_device *phydev, struct ethtool_eee *data)
 {
         int val = ethtool_adv_to_mmd_eee_adv_t(data->advertised);
 
-        phy_write_mmd_indirect(phydev->bus, MDIO_AN_EEE_ADV, MDIO_MMD_AN,
+        phy_write_mmd_indirect(phydev, MDIO_AN_EEE_ADV, MDIO_MMD_AN,
                                phydev->addr, val);
 
         return 0;
diff --git a/include/linux/phy.h b/include/linux/phy.h
index 68041446c450..ed39956b5613 100644
--- a/include/linux/phy.h
+++ b/include/linux/phy.h
@@ -545,6 +545,24 @@ struct phy_driver {
          */
         void (*link_change_notify)(struct phy_device *dev);
 
+        /* A function provided by a phy specific driver to override the
+         * the PHY driver framework support for reading a MMD register
+         * from the PHY. If not supported, return -1. This function is
+         * optional for PHY specific drivers, if not provided then the
+         * default MMD read function is used by the PHY framework.
+         */
+        int (*read_mmd_indirect)(struct phy_device *dev, int ptrad,
+                                 int devnum, int regnum);
+
+        /* A function provided by a phy specific driver to override the
+         * the PHY driver framework support for writing a MMD register
+         * from the PHY. This function is optional for PHY specific drivers,
+         * if not provided then the default MMD read function is used by
+         * the PHY framework.
+         */
+        void (*write_mmd_indirect)(struct phy_device *dev, int ptrad,
+                                   int devnum, int regnum, u32 val);
+
         struct device_driver driver;
 };
 #define to_phy_driver(d) container_of(d, struct phy_driver, driver)