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 * @priv: Pointer to ARC EMAC private data structure. 104 * 105 * returns: 0 on success, -ENOMEM when mdiobus_alloc 106 * (to allocate memory for MII bus structure) fails. 107 * 108 * Sets up and registers the MDIO interface. 109 */ 110 int arc_mdio_probe(struct arc_emac_priv *priv) 111 { 112 struct mii_bus *bus; 113 int error; 114 115 bus = mdiobus_alloc(); 116 if (!bus) 117 return -ENOMEM; 118 119 priv->bus = bus; 120 bus->priv = priv; 121 bus->parent = priv->dev; 122 bus->name = "Synopsys MII Bus", 123 bus->read = &arc_mdio_read; 124 bus->write = &arc_mdio_write; 125 126 snprintf(bus->id, MII_BUS_ID_SIZE, "%s", bus->name); 127 128 error = of_mdiobus_register(bus, priv->dev->of_node); 129 if (error) { 130 dev_err(priv->dev, "cannot register MDIO bus %s\n", bus->name); 131 mdiobus_free(bus); 132 return error; 133 } 134 135 return 0; 136 } 137 138 /** 139 * arc_mdio_remove - MDIO remove function. 140 * @priv: Pointer to ARC EMAC private data structure. 141 * 142 * Unregisters the MDIO and frees any associate memory for MII bus. 143 */ 144 int arc_mdio_remove(struct arc_emac_priv *priv) 145 { 146 mdiobus_unregister(priv->bus); 147 mdiobus_free(priv->bus); 148 priv->bus = NULL; 149 150 return 0; 151 } 152