drivers/net/ethernet/arc/emac_mdio.c

   1 /*
   2  * Copyright (C) 2004-2013 Synopsys, Inc. (www.synopsys.com)
   3  *
   4  * MDIO implementation for ARC EMAC
   5  */
   6
   7 #include <linux/delay.h>
   8 #include <linux/of_mdio.h>
   9 #include <linux/platform_device.h>
  10
  11 #include "emac.h"
  12
  13 /* Number of seconds we wait for "MDIO complete" flag to appear */
  14 #define ARC_MDIO_COMPLETE_POLL_COUNT    1
  15
  16 /**
  17  * arc_mdio_complete_wait - Waits until MDIO transaction is completed.
  18  * @priv:       Pointer to ARC EMAC private data structure.
  19  *
  20  * returns:     0 on success, -ETIMEDOUT on a timeout.
  21  */
  22 static int arc_mdio_complete_wait(struct arc_emac_priv *priv)
  23 {
  24         unsigned int i;
  25
  26         for (i = 0; i < ARC_MDIO_COMPLETE_POLL_COUNT * 40; i++) {
  27                 unsigned int status = arc_reg_get(priv, R_STATUS);
  28
  29                 status &= MDIO_MASK;
  30
  31                 if (status) {
  32                         /* Reset "MDIO complete" flag */
  33                         arc_reg_set(priv, R_STATUS, status);
  34                         return 0;
  35                 }
  36
  37                 msleep(25);
  38         }
  39
  40         return -ETIMEDOUT;
  41 }
  42
  43 /**
  44  * arc_mdio_read - MDIO interface read function.
  45  * @bus:        Pointer to MII bus structure.
  46  * @phy_addr:   Address of the PHY device.
  47  * @reg_num:    PHY register to read.
  48  *
  49  * returns:     The register contents on success, -ETIMEDOUT on a timeout.
  50  *
  51  * Reads the contents of the requested register from the requested PHY
  52  * address.
  53  */
  54 static int arc_mdio_read(struct mii_bus *bus, int phy_addr, int reg_num)
  55 {
  56         struct arc_emac_priv *priv = bus->priv;
  57         unsigned int value;
  58         int error;
  59
  60         arc_reg_set(priv, R_MDIO,
  61                     0x60020000 | (phy_addr << 23) | (reg_num << 18));
  62
  63         error = arc_mdio_complete_wait(priv);
  64         if (error < 0)
  65                 return error;
  66
  67         value = arc_reg_get(priv, R_MDIO) & 0xffff;
  68
  69         dev_dbg(priv->dev, "arc_mdio_read(phy_addr=%i, reg_num=%x) = %x\n",
  70                 phy_addr, reg_num, value);
  71
  72         return value;
  73 }
  74
  75 /**
  76  * arc_mdio_write - MDIO interface write function.
  77  * @bus:        Pointer to MII bus structure.
  78  * @phy_addr:   Address of the PHY device.
  79  * @reg_num:    PHY register to write to.
  80  * @value:      Value to be written into the register.
  81  *
  82  * returns:     0 on success, -ETIMEDOUT on a timeout.
  83  *
  84  * Writes the value to the requested register.
  85  */
  86 static int arc_mdio_write(struct mii_bus *bus, int phy_addr,
  87                           int reg_num, u16 value)
  88 {
  89         struct arc_emac_priv *priv = bus->priv;
  90
  91         dev_dbg(priv->dev,
  92                 "arc_mdio_write(phy_addr=%i, reg_num=%x, value=%x)\n",
  93                 phy_addr, reg_num, value);
  94
  95         arc_reg_set(priv, R_MDIO,
  96                      0x50020000 | (phy_addr << 23) | (reg_num << 18) | value);
  97
  98         return arc_mdio_complete_wait(priv);
  99 }
 100
 101 /**
 102  * arc_mdio_probe - MDIO probe function.
 103  * @pdev:       Pointer to platform device.
 104  * @priv:       Pointer to ARC EMAC private data structure.
 105  *
 106  * returns:     0 on success, -ENOMEM when mdiobus_alloc
 107  * (to allocate memory for MII bus structure) fails.
 108  *
 109  * Sets up and registers the MDIO interface.
 110  */
 111 int arc_mdio_probe(struct platform_device *pdev, struct arc_emac_priv *priv)
 112 {
 113         struct mii_bus *bus;
 114         int error;
 115
 116         bus = mdiobus_alloc();
 117         if (!bus)
 118                 return -ENOMEM;
 119
 120         priv->bus = bus;
 121         bus->priv = priv;
 122         bus->parent = priv->dev;
 123         bus->name = "Synopsys MII Bus",
 124         bus->read = &arc_mdio_read;
 125         bus->write = &arc_mdio_write;
 126
 127         snprintf(bus->id, MII_BUS_ID_SIZE, "%s", pdev->name);
 128
 129         error = of_mdiobus_register(bus, pdev->dev.of_node);
 130         if (error) {
 131                 dev_err(priv->dev, "cannot register MDIO bus %s\n", bus->name);
 132                 mdiobus_free(bus);
 133                 return error;
 134         }
 135
 136         return 0;
 137 }
 138
 139 /**
 140  * arc_mdio_remove - MDIO remove function.
 141  * @priv:       Pointer to ARC EMAC private data structure.
 142  *
 143  * Unregisters the MDIO and frees any associate memory for MII bus.
 144  */
 145 int arc_mdio_remove(struct arc_emac_priv *priv)
 146 {
 147         mdiobus_unregister(priv->bus);
 148         mdiobus_free(priv->bus);
 149         priv->bus = NULL;
 150
 151         return 0;
 152 }