/*
 * B53 register access through MII registers
 *
 * Copyright (C) 2011-2013 Jonas Gorski <jogo@openwrt.org>
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <linux/kernel.h>
#include <linux/phy.h>
#include <linux/module.h>
#include <linux/delay.h>
#include <linux/brcmphy.h>
#include <linux/rtnetlink.h>
#include <net/dsa.h>

#include "b53_priv.h"

/* MII registers */
#define REG_MII_PAGE    0x10    /* MII Page register */
#define REG_MII_ADDR    0x11    /* MII Address register */
#define REG_MII_DATA0   0x18    /* MII Data register 0 */
#define REG_MII_DATA1   0x19    /* MII Data register 1 */
#define REG_MII_DATA2   0x1a    /* MII Data register 2 */
#define REG_MII_DATA3   0x1b    /* MII Data register 3 */

#define REG_MII_PAGE_ENABLE     BIT(0)
#define REG_MII_ADDR_WRITE      BIT(0)
#define REG_MII_ADDR_READ       BIT(1)

static int b53_mdio_op(struct b53_device *dev, u8 page, u8 reg, u16 op)
{
	int i;
	u16 v;
	int ret;
	struct mii_bus *bus = dev->priv;

	if (dev->current_page != page) {
		/* set page number */
		v = (page << 8) | REG_MII_PAGE_ENABLE;
		ret = mdiobus_write_nested(bus, BRCM_PSEUDO_PHY_ADDR,
					   REG_MII_PAGE, v);
		if (ret)
			return ret;
		dev->current_page = page;
	}

	/* set register address */
	v = (reg << 8) | op;
	ret = mdiobus_write_nested(bus, BRCM_PSEUDO_PHY_ADDR, REG_MII_ADDR, v);
	if (ret)
		return ret;

	/* check if operation completed */
	for (i = 0; i < 5; ++i) {
		v = mdiobus_read_nested(bus, BRCM_PSEUDO_PHY_ADDR,
					REG_MII_ADDR);
		if (!(v & (REG_MII_ADDR_WRITE | REG_MII_ADDR_READ)))
			break;
		usleep_range(10, 100);
	}

	if (WARN_ON(i == 5))
		return -EIO;

	return 0;
}

static int b53_mdio_read8(struct b53_device *dev, u8 page, u8 reg, u8 *val)
{
	struct mii_bus *bus = dev->priv;
	int ret;

	ret = b53_mdio_op(dev, page, reg, REG_MII_ADDR_READ);
	if (ret)
		return ret;

	*val = mdiobus_read_nested(bus, BRCM_PSEUDO_PHY_ADDR,
				   REG_MII_DATA0) & 0xff;

	return 0;
}

static int b53_mdio_read16(struct b53_device *dev, u8 page, u8 reg, u16 *val)
{
	struct mii_bus *bus = dev->priv;
	int ret;

	ret = b53_mdio_op(dev, page, reg, REG_MII_ADDR_READ);
	if (ret)
		return ret;

	*val = mdiobus_read_nested(bus, BRCM_PSEUDO_PHY_ADDR, REG_MII_DATA0);

	return 0;
}

static int b53_mdio_read32(struct b53_device *dev, u8 page, u8 reg, u32 *val)
{
	struct mii_bus *bus = dev->priv;
	int ret;

	ret = b53_mdio_op(dev, page, reg, REG_MII_ADDR_READ);
	if (ret)
		return ret;

	*val = mdiobus_read_nested(bus, BRCM_PSEUDO_PHY_ADDR, REG_MII_DATA0);
	*val |= mdiobus_read_nested(bus, BRCM_PSEUDO_PHY_ADDR,
				    REG_MII_DATA1) << 16;

	return 0;
}

static int b53_mdio_read48(struct b53_device *dev, u8 page, u8 reg, u64 *val)
{
	struct mii_bus *bus = dev->priv;
	u64 temp = 0;
	int i;
	int ret;

	ret = b53_mdio_op(dev, page, reg, REG_MII_ADDR_READ);
	if (ret)
		return ret;

	for (i = 2; i >= 0; i--) {
		temp <<= 16;
		temp |= mdiobus_read_nested(bus, BRCM_PSEUDO_PHY_ADDR,
				     REG_MII_DATA0 + i);
	}

	*val = temp;

	return 0;
}

static int b53_mdio_read64(struct b53_device *dev, u8 page, u8 reg, u64 *val)
{
	struct mii_bus *bus = dev->priv;
	u64 temp = 0;
	int i;
	int ret;

	ret = b53_mdio_op(dev, page, reg, REG_MII_ADDR_READ);
	if (ret)
		return ret;

	for (i = 3; i >= 0; i--) {
		temp <<= 16;
		temp |= mdiobus_read_nested(bus, BRCM_PSEUDO_PHY_ADDR,
					    REG_MII_DATA0 + i);
	}

	*val = temp;

	return 0;
}

static int b53_mdio_write8(struct b53_device *dev, u8 page, u8 reg, u8 value)
{
	struct mii_bus *bus = dev->priv;
	int ret;

	ret = mdiobus_write_nested(bus, BRCM_PSEUDO_PHY_ADDR,
				   REG_MII_DATA0, value);
	if (ret)
		return ret;

	return b53_mdio_op(dev, page, reg, REG_MII_ADDR_WRITE);
}

static int b53_mdio_write16(struct b53_device *dev, u8 page, u8 reg,
			    u16 value)
{
	struct mii_bus *bus = dev->priv;
	int ret;

	ret = mdiobus_write_nested(bus, BRCM_PSEUDO_PHY_ADDR,
				   REG_MII_DATA0, value);
	if (ret)
		return ret;

	return b53_mdio_op(dev, page, reg, REG_MII_ADDR_WRITE);
}

static int b53_mdio_write32(struct b53_device *dev, u8 page, u8 reg,
			    u32 value)
{
	struct mii_bus *bus = dev->priv;
	unsigned int i;
	u32 temp = value;

	for (i = 0; i < 2; i++) {
		int ret = mdiobus_write_nested(bus, BRCM_PSEUDO_PHY_ADDR,
					       REG_MII_DATA0 + i,
					       temp & 0xffff);
		if (ret)
			return ret;
		temp >>= 16;
	}

	return b53_mdio_op(dev, page, reg, REG_MII_ADDR_WRITE);
}

static int b53_mdio_write48(struct b53_device *dev, u8 page, u8 reg,
			    u64 value)
{
	struct mii_bus *bus = dev->priv;
	unsigned int i;
	u64 temp = value;

	for (i = 0; i < 3; i++) {
		int ret = mdiobus_write_nested(bus, BRCM_PSEUDO_PHY_ADDR,
					       REG_MII_DATA0 + i,
					       temp & 0xffff);
		if (ret)
			return ret;
		temp >>= 16;
	}

	return b53_mdio_op(dev, page, reg, REG_MII_ADDR_WRITE);
}

static int b53_mdio_write64(struct b53_device *dev, u8 page, u8 reg,
			    u64 value)
{
	struct mii_bus *bus = dev->priv;
	unsigned int i;
	u64 temp = value;

	for (i = 0; i < 4; i++) {
		int ret = mdiobus_write_nested(bus, BRCM_PSEUDO_PHY_ADDR,
					       REG_MII_DATA0 + i,
					       temp & 0xffff);
		if (ret)
			return ret;
		temp >>= 16;
	}

	return b53_mdio_op(dev, page, reg, REG_MII_ADDR_WRITE);
}

static int b53_mdio_phy_read16(struct b53_device *dev, int addr, int reg,
			       u16 *value)
{
	struct mii_bus *bus = dev->priv;

	*value = mdiobus_read_nested(bus, addr, reg);

	return 0;
}

static int b53_mdio_phy_write16(struct b53_device *dev, int addr, int reg,
				u16 value)
{
	struct mii_bus *bus = dev->bus;

	return mdiobus_write_nested(bus, addr, reg, value);
}

static const struct b53_io_ops b53_mdio_ops = {
	.read8 = b53_mdio_read8,
	.read16 = b53_mdio_read16,
	.read32 = b53_mdio_read32,
	.read48 = b53_mdio_read48,
	.read64 = b53_mdio_read64,
	.write8 = b53_mdio_write8,
	.write16 = b53_mdio_write16,
	.write32 = b53_mdio_write32,
	.write48 = b53_mdio_write48,
	.write64 = b53_mdio_write64,
	.phy_read16 = b53_mdio_phy_read16,
	.phy_write16 = b53_mdio_phy_write16,
};

#define B53_BRCM_OUI_1	0x0143bc00
#define B53_BRCM_OUI_2	0x03625c00
#define B53_BRCM_OUI_3	0x00406000

static int b53_mdio_probe(struct mdio_device *mdiodev)
{
	struct b53_device *dev;
	u32 phy_id;
	int ret;

	/* allow the generic PHY driver to take over the non-management MDIO
	 * addresses
	 */
	if (mdiodev->addr != BRCM_PSEUDO_PHY_ADDR && mdiodev->addr != 0) {
		dev_err(&mdiodev->dev, "leaving address %d to PHY\n",
			mdiodev->addr);
		return -ENODEV;
	}

	/* read the first port's id */
	phy_id = mdiobus_read(mdiodev->bus, 0, 2) << 16;
	phy_id |= mdiobus_read(mdiodev->bus, 0, 3);

	/* BCM5325, BCM539x (OUI_1)
	 * BCM53125, BCM53128 (OUI_2)
	 * BCM5365 (OUI_3)
	 */
	if ((phy_id & 0xfffffc00) != B53_BRCM_OUI_1 &&
	    (phy_id & 0xfffffc00) != B53_BRCM_OUI_2 &&
	    (phy_id & 0xfffffc00) != B53_BRCM_OUI_3) {
		dev_err(&mdiodev->dev, "Unsupported device: 0x%08x\n", phy_id);
		return -ENODEV;
	}

	/* First probe will come from SWITCH_MDIO controller on the 7445D0
	 * switch, which will conflict with the 7445 integrated switch
	 * pseudo-phy (we end-up programming both). In that case, we return
	 * -EPROBE_DEFER for the first time we get here, and wait until we come
	 * back with the slave MDIO bus which has the correct indirection
	 * layer setup
	 */
	if (of_machine_is_compatible("brcm,bcm7445d0") &&
	    strcmp(mdiodev->bus->name, "sf2 slave mii"))
		return -EPROBE_DEFER;

	dev = b53_switch_alloc(&mdiodev->dev, &b53_mdio_ops, mdiodev->bus);
	if (!dev)
		return -ENOMEM;

	/* we don't use page 0xff, so force a page set */
	dev->current_page = 0xff;
	dev->bus = mdiodev->bus;

	dev_set_drvdata(&mdiodev->dev, dev);

	ret = b53_switch_register(dev);
	if (ret) {
		dev_err(&mdiodev->dev, "failed to register switch: %i\n", ret);
		return ret;
	}

	return ret;
}

static void b53_mdio_remove(struct mdio_device *mdiodev)
{
	struct b53_device *dev = dev_get_drvdata(&mdiodev->dev);
	struct dsa_switch *ds = dev->ds;

	dsa_unregister_switch(ds);
}

static const struct of_device_id b53_of_match[] = {
	{ .compatible = "brcm,bcm5325" },
	{ .compatible = "brcm,bcm53115" },
	{ .compatible = "brcm,bcm53125" },
	{ .compatible = "brcm,bcm53128" },
	{ .compatible = "brcm,bcm5365" },
	{ .compatible = "brcm,bcm5395" },
	{ .compatible = "brcm,bcm5397" },
	{ .compatible = "brcm,bcm5398" },
	{ /* sentinel */ },
};
MODULE_DEVICE_TABLE(of, b53_of_match);

static struct mdio_driver b53_mdio_driver = {
	.probe	= b53_mdio_probe,
	.remove	= b53_mdio_remove,
	.mdiodrv.driver = {
		.name = "bcm53xx",
		.of_match_table = b53_of_match,
	},
};

static int __init b53_mdio_driver_register(void)
{
	return mdio_driver_register(&b53_mdio_driver);
}
module_init(b53_mdio_driver_register);

static void __exit b53_mdio_driver_unregister(void)
{
	mdio_driver_unregister(&b53_mdio_driver);
}
module_exit(b53_mdio_driver_unregister);

MODULE_DESCRIPTION("B53 MDIO access driver");
MODULE_LICENSE("Dual BSD/GPL");