/*
 * Combined Ethernet driver for Motorola MPC8xx and MPC82xx.
 *
 * Copyright (c) 2003 Intracom S.A.
 *  by Pantelis Antoniou <panto@intracom.gr>
 *
 * 2005 (c) MontaVista Software, Inc.
 * Vitaly Bordug <vbordug@ru.mvista.com>
 *
 * This file is licensed under the terms of the GNU General Public License
 * version 2. This program is licensed "as is" without any warranty of any
 * kind, whether express or implied.
 */

#include <linux/module.h>
#include <linux/ioport.h>
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/mii.h>
#include <linux/ethtool.h>
#include <linux/bitops.h>
#include <linux/platform_device.h>

#ifdef CONFIG_PPC_CPM_NEW_BINDING
#include <linux/of_platform.h>
#endif

#include "fs_enet.h"

struct bb_info {
	__be32 __iomem *dir;
	__be32 __iomem *dat;
	u32 mdio_msk;
	u32 mdc_msk;
	int delay;
};

/* FIXME: If any other users of GPIO crop up, then these will have to
 * have some sort of global synchronization to avoid races with other
 * pins on the same port.  The ideal solution would probably be to
 * bind the ports to a GPIO driver, and have this be a client of it.
 */
static inline void bb_set(u32 __iomem *p, u32 m)
{
	out_be32(p, in_be32(p) | m);
}

static inline void bb_clr(u32 __iomem *p, u32 m)
{
	out_be32(p, in_be32(p) & ~m);
}

static inline int bb_read(u32 __iomem *p, u32 m)
{
	return (in_be32(p) & m) != 0;
}

static inline void mdio_active(struct bb_info *bitbang)
{
	bb_set(bitbang->dir, bitbang->mdio_msk);
}

static inline void mdio_tristate(struct bb_info *bitbang)
{
	bb_clr(bitbang->dir, bitbang->mdio_msk);
}

static inline int mdio_read(struct bb_info *bitbang)
{
	return bb_read(bitbang->dat, bitbang->mdio_msk);
}

static inline void mdio(struct bb_info *bitbang, int what)
{
	if (what)
		bb_set(bitbang->dat, bitbang->mdio_msk);
	else
		bb_clr(bitbang->dat, bitbang->mdio_msk);
}

static inline void mdc(struct bb_info *bitbang, int what)
{
	if (what)
		bb_set(bitbang->dat, bitbang->mdc_msk);
	else
		bb_clr(bitbang->dat, bitbang->mdc_msk);
}

static inline void mii_delay(struct bb_info *bitbang)
{
	udelay(bitbang->delay);
}

/* Utility to send the preamble, address, and register (common to read and write). */
static void bitbang_pre(struct bb_info *bitbang , int read, u8 addr, u8 reg)
{
	int j;

	/*
	 * Send a 32 bit preamble ('1's) with an extra '1' bit for good measure.
	 * The IEEE spec says this is a PHY optional requirement.  The AMD
	 * 79C874 requires one after power up and one after a MII communications
	 * error.  This means that we are doing more preambles than we need,
	 * but it is safer and will be much more robust.
	 */

	mdio_active(bitbang);
	mdio(bitbang, 1);
	for (j = 0; j < 32; j++) {
		mdc(bitbang, 0);
		mii_delay(bitbang);
		mdc(bitbang, 1);
		mii_delay(bitbang);
	}

	/* send the start bit (01) and the read opcode (10) or write (10) */
	mdc(bitbang, 0);
	mdio(bitbang, 0);
	mii_delay(bitbang);
	mdc(bitbang, 1);
	mii_delay(bitbang);
	mdc(bitbang, 0);
	mdio(bitbang, 1);
	mii_delay(bitbang);
	mdc(bitbang, 1);
	mii_delay(bitbang);
	mdc(bitbang, 0);
	mdio(bitbang, read);
	mii_delay(bitbang);
	mdc(bitbang, 1);
	mii_delay(bitbang);
	mdc(bitbang, 0);
	mdio(bitbang, !read);
	mii_delay(bitbang);
	mdc(bitbang, 1);
	mii_delay(bitbang);

	/* send the PHY address */
	for (j = 0; j < 5; j++) {
		mdc(bitbang, 0);
		mdio(bitbang, (addr & 0x10) != 0);
		mii_delay(bitbang);
		mdc(bitbang, 1);
		mii_delay(bitbang);
		addr <<= 1;
	}

	/* send the register address */
	for (j = 0; j < 5; j++) {
		mdc(bitbang, 0);
		mdio(bitbang, (reg & 0x10) != 0);
		mii_delay(bitbang);
		mdc(bitbang, 1);
		mii_delay(bitbang);
		reg <<= 1;
	}
}

static int fs_enet_mii_bb_read(struct mii_bus *bus , int phy_id, int location)
{
	u16 rdreg;
	int ret, j;
	u8 addr = phy_id & 0xff;
	u8 reg = location & 0xff;
	struct bb_info* bitbang = bus->priv;

	bitbang_pre(bitbang, 1, addr, reg);

	/* tri-state our MDIO I/O pin so we can read */
	mdc(bitbang, 0);
	mdio_tristate(bitbang);
	mii_delay(bitbang);
	mdc(bitbang, 1);
	mii_delay(bitbang);

	/* check the turnaround bit: the PHY should be driving it to zero */
	if (mdio_read(bitbang) != 0) {
		/* PHY didn't drive TA low */
		for (j = 0; j < 32; j++) {
			mdc(bitbang, 0);
			mii_delay(bitbang);
			mdc(bitbang, 1);
			mii_delay(bitbang);
		}
		ret = -1;
		goto out;
	}

	mdc(bitbang, 0);
	mii_delay(bitbang);

	/* read 16 bits of register data, MSB first */
	rdreg = 0;
	for (j = 0; j < 16; j++) {
		mdc(bitbang, 1);
		mii_delay(bitbang);
		rdreg <<= 1;
		rdreg |= mdio_read(bitbang);
		mdc(bitbang, 0);
		mii_delay(bitbang);
	}

	mdc(bitbang, 1);
	mii_delay(bitbang);
	mdc(bitbang, 0);
	mii_delay(bitbang);
	mdc(bitbang, 1);
	mii_delay(bitbang);

	ret = rdreg;
out:
	return ret;
}

static int fs_enet_mii_bb_write(struct mii_bus *bus, int phy_id, int location, u16 val)
{
	int j;
	struct bb_info* bitbang = bus->priv;

	u8 addr = phy_id & 0xff;
	u8 reg = location & 0xff;
	u16 value = val & 0xffff;

	bitbang_pre(bitbang, 0, addr, reg);

	/* send the turnaround (10) */
	mdc(bitbang, 0);
	mdio(bitbang, 1);
	mii_delay(bitbang);
	mdc(bitbang, 1);
	mii_delay(bitbang);
	mdc(bitbang, 0);
	mdio(bitbang, 0);
	mii_delay(bitbang);
	mdc(bitbang, 1);
	mii_delay(bitbang);

	/* write 16 bits of register data, MSB first */
	for (j = 0; j < 16; j++) {
		mdc(bitbang, 0);
		mdio(bitbang, (value & 0x8000) != 0);
		mii_delay(bitbang);
		mdc(bitbang, 1);
		mii_delay(bitbang);
		value <<= 1;
	}

	/*
	 * Tri-state the MDIO line.
	 */
	mdio_tristate(bitbang);
	mdc(bitbang, 0);
	mii_delay(bitbang);
	mdc(bitbang, 1);
	mii_delay(bitbang);
	return 0;
}

static int fs_enet_mii_bb_reset(struct mii_bus *bus)
{
	/*nothing here - dunno how to reset it*/
	return 0;
}

#ifdef CONFIG_PPC_CPM_NEW_BINDING
static int __devinit fs_mii_bitbang_init(struct mii_bus *bus,
                                         struct device_node *np)
{
	struct resource res;
	const u32 *data;
	int mdio_pin, mdc_pin, len;
	struct bb_info *bitbang = bus->priv;

	int ret = of_address_to_resource(np, 0, &res);
	if (ret)
		return ret;

	if (res.end - res.start < 13)
		return -ENODEV;

	/* This should really encode the pin number as well, but all
	 * we get is an int, and the odds of multiple bitbang mdio buses
	 * is low enough that it's not worth going too crazy.
	 */
	bus->id = res.start;

	data = of_get_property(np, "fsl,mdio-pin", &len);
	if (!data || len != 4)
		return -ENODEV;
	mdio_pin = *data;

	data = of_get_property(np, "fsl,mdc-pin", &len);
	if (!data || len != 4)
		return -ENODEV;
	mdc_pin = *data;

	bitbang->dir = ioremap(res.start, res.end - res.start + 1);
	if (!bitbang->dir)
		return -ENOMEM;

	bitbang->dat = bitbang->dir + 4;
	bitbang->mdio_msk = 1 << (31 - mdio_pin);
	bitbang->mdc_msk = 1 << (31 - mdc_pin);
	bitbang->delay = 1; /* 1 us between operations */

	return 0;
}

static void __devinit add_phy(struct mii_bus *bus, struct device_node *np)
{
	const u32 *data;
	int len, id, irq;

	data = of_get_property(np, "reg", &len);
	if (!data || len != 4)
		return;

	id = *data;
	bus->phy_mask &= ~(1 << id);

	irq = of_irq_to_resource(np, 0, NULL);
	if (irq != NO_IRQ)
		bus->irq[id] = irq;
}

static int __devinit fs_enet_mdio_probe(struct of_device *ofdev,
                                        const struct of_device_id *match)
{
	struct device_node *np = NULL;
	struct mii_bus *new_bus;
	struct bb_info *bitbang;
	int ret = -ENOMEM;
	int i;

	new_bus = kzalloc(sizeof(struct mii_bus), GFP_KERNEL);
	if (!new_bus)
		goto out;

	bitbang = kzalloc(sizeof(struct bb_info), GFP_KERNEL);
	if (!bitbang)
		goto out_free_bus;

	new_bus->priv = bitbang;
	new_bus->name = "CPM2 Bitbanged MII",
	new_bus->read = &fs_enet_mii_bb_read,
	new_bus->write = &fs_enet_mii_bb_write,
	new_bus->reset = &fs_enet_mii_bb_reset,

	ret = fs_mii_bitbang_init(new_bus, ofdev->node);
	if (ret)
		goto out_free_bitbang;

	new_bus->phy_mask = ~0;
	new_bus->irq = kmalloc(sizeof(int) * PHY_MAX_ADDR, GFP_KERNEL);
	if (!new_bus->irq)
		goto out_unmap_regs;

	for (i = 0; i < PHY_MAX_ADDR; i++)
		new_bus->irq[i] = -1;

	while ((np = of_get_next_child(ofdev->node, np)))
		if (!strcmp(np->type, "ethernet-phy"))
			add_phy(new_bus, np);

	new_bus->dev = &ofdev->dev;
	dev_set_drvdata(&ofdev->dev, new_bus);

	ret = mdiobus_register(new_bus);
	if (ret)
		goto out_free_irqs;

	return 0;

out_free_irqs:
	dev_set_drvdata(&ofdev->dev, NULL);
	kfree(new_bus->irq);
out_unmap_regs:
	iounmap(bitbang->dir);
out_free_bitbang:
	kfree(bitbang);
out_free_bus:
	kfree(new_bus);
out:
	return ret;
}

static int fs_enet_mdio_remove(struct of_device *ofdev)
{
	struct mii_bus *bus = dev_get_drvdata(&ofdev->dev);
	struct bb_info *bitbang = bus->priv;

	mdiobus_unregister(bus);
	dev_set_drvdata(&ofdev->dev, NULL);
	kfree(bus->irq);
	iounmap(bitbang->dir);
	kfree(bitbang);
	kfree(bus);

	return 0;
}

static struct of_device_id fs_enet_mdio_bb_match[] = {
	{
		.compatible = "fsl,cpm2-mdio-bitbang",
	},
	{},
};

static struct of_platform_driver fs_enet_bb_mdio_driver = {
	.name = "fsl-bb-mdio",
	.match_table = fs_enet_mdio_bb_match,
	.probe = fs_enet_mdio_probe,
	.remove = fs_enet_mdio_remove,
};

int fs_enet_mdio_bb_init(void)
{
	return of_register_platform_driver(&fs_enet_bb_mdio_driver);
}

void fs_enet_mdio_bb_exit(void)
{
	of_unregister_platform_driver(&fs_enet_bb_mdio_driver);
}

module_init(fs_enet_mdio_bb_init);
module_exit(fs_enet_mdio_bb_exit);
#else
static int __devinit fs_mii_bitbang_init(struct bb_info *bitbang,
                                         struct fs_mii_bb_platform_info *fmpi)
{
	bitbang->dir = (u32 __iomem *)fmpi->mdio_dir.offset;
	bitbang->dat = (u32 __iomem *)fmpi->mdio_dat.offset;
	bitbang->mdio_msk = 1U << (31 - fmpi->mdio_dat.bit);
	bitbang->mdc_msk = 1U << (31 - fmpi->mdc_dat.bit);
	bitbang->delay = fmpi->delay;

	return 0;
}

static int __devinit fs_enet_mdio_probe(struct device *dev)
{
	struct platform_device *pdev = to_platform_device(dev);
	struct fs_mii_bb_platform_info *pdata;
	struct mii_bus *new_bus;
	struct bb_info *bitbang;
	int err = 0;

	if (NULL == dev)
		return -EINVAL;

	new_bus = kzalloc(sizeof(struct mii_bus), GFP_KERNEL);

	if (NULL == new_bus)
		return -ENOMEM;

	bitbang = kzalloc(sizeof(struct bb_info), GFP_KERNEL);

	if (NULL == bitbang)
		return -ENOMEM;

	new_bus->name = "BB MII Bus",
	new_bus->read = &fs_enet_mii_bb_read,
	new_bus->write = &fs_enet_mii_bb_write,
	new_bus->reset = &fs_enet_mii_bb_reset,
	new_bus->id = pdev->id;

	new_bus->phy_mask = ~0x9;
	pdata = (struct fs_mii_bb_platform_info *)pdev->dev.platform_data;

	if (NULL == pdata) {
		printk(KERN_ERR "gfar mdio %d: Missing platform data!\n", pdev->id);
		return -ENODEV;
	}

	/*set up workspace*/
	fs_mii_bitbang_init(bitbang, pdata);

	new_bus->priv = bitbang;

	new_bus->irq = pdata->irq;

	new_bus->dev = dev;
	dev_set_drvdata(dev, new_bus);

	err = mdiobus_register(new_bus);

	if (0 != err) {
		printk (KERN_ERR "%s: Cannot register as MDIO bus\n",
				new_bus->name);
		goto bus_register_fail;
	}

	return 0;

bus_register_fail:
	kfree(bitbang);
	kfree(new_bus);

	return err;
}

static int fs_enet_mdio_remove(struct device *dev)
{
	struct mii_bus *bus = dev_get_drvdata(dev);

	mdiobus_unregister(bus);

	dev_set_drvdata(dev, NULL);

	iounmap((void *) (&bus->priv));
	bus->priv = NULL;
	kfree(bus);

	return 0;
}

static struct device_driver fs_enet_bb_mdio_driver = {
	.name = "fsl-bb-mdio",
	.bus = &platform_bus_type,
	.probe = fs_enet_mdio_probe,
	.remove = fs_enet_mdio_remove,
};

int fs_enet_mdio_bb_init(void)
{
	return driver_register(&fs_enet_bb_mdio_driver);
}

void fs_enet_mdio_bb_exit(void)
{
	driver_unregister(&fs_enet_bb_mdio_driver);
}