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 */
 22static 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 */
 54static 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 */
 86static 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 */
111int 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 */
145int 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}