/*
 * Allwinner EMAC MDIO interface driver
 *
 * Copyright 2012-2013 Stefan Roese <sr@denx.de>
 * Copyright 2013 Maxime Ripard <maxime.ripard@free-electrons.com>
 *
 * Based on the Linux driver provided by Allwinner:
 * Copyright (C) 1997  Sten Wang
 *
 * 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/delay.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/slab.h>
#include <linux/of_address.h>
#include <linux/of_mdio.h>
#include <linux/phy.h>
#include <linux/platform_device.h>
#include <linux/regulator/consumer.h>

#define MODULE_DESC			"Allwinner EMAC MDIO interface driver"
#define MODULE_AUTHOR			"Pranav Sawargaonkar"
#define MODULE_LICENSE			"GPL"
#define MODULE_IPRIORITY		(VMM_NET_CLASS_IPRIORITY + 1)
#define MODULE_INIT			sun4i_mdio_driver_init
#define MODULE_EXIT			sun4i_mdio_driver_exit

#define EMAC_MAC_MCMD_REG	(0x00)
#define EMAC_MAC_MADR_REG	(0x04)
#define EMAC_MAC_MWTD_REG	(0x08)
#define EMAC_MAC_MRDD_REG	(0x0c)
#define EMAC_MAC_MIND_REG	(0x10)
#define EMAC_MAC_SSRR_REG	(0x14)

#define MDIO_TIMEOUT		(msecs_to_jiffies(100))

struct sun4i_mdio_data {
	void __iomem		*membase;
	struct regulator	*regulator;
};

static int sun4i_mdio_read(struct mii_bus *bus, int mii_id, int regnum)
{
	struct sun4i_mdio_data *data = bus->priv;
	unsigned long timeout_jiffies;
	int value;

	/* issue the phy address and reg */
	writel((mii_id << 8) | regnum, data->membase + EMAC_MAC_MADR_REG);
	/* pull up the phy io line */
	writel(0x1, data->membase + EMAC_MAC_MCMD_REG);

	/* Wait read complete */
	timeout_jiffies = jiffies + MDIO_TIMEOUT;
	while (readl(data->membase + EMAC_MAC_MIND_REG) & 0x1) {
		if (time_is_before_jiffies(timeout_jiffies))
			return -ETIMEDOUT;
		msleep(1);
	}

	/* push down the phy io line */
	writel(0x0, data->membase + EMAC_MAC_MCMD_REG);
	/* and read data */
	value = readl(data->membase + EMAC_MAC_MRDD_REG);

	return value;
}

static int sun4i_mdio_write(struct mii_bus *bus, int mii_id, int regnum,
			    u16 value)
{
	struct sun4i_mdio_data *data = bus->priv;
	unsigned long timeout_jiffies;

	/* issue the phy address and reg */
	writel((mii_id << 8) | regnum, data->membase + EMAC_MAC_MADR_REG);
	/* pull up the phy io line */
	writel(0x1, data->membase + EMAC_MAC_MCMD_REG);

	/* Wait read complete */
	timeout_jiffies = jiffies + MDIO_TIMEOUT;
	while (readl(data->membase + EMAC_MAC_MIND_REG) & 0x1) {
		if (time_is_before_jiffies(timeout_jiffies))
			return -ETIMEDOUT;
		msleep(1);
	}

	/* push down the phy io line */
	writel(0x0, data->membase + EMAC_MAC_MCMD_REG);
	/* and write data */
	writel(value, data->membase + EMAC_MAC_MWTD_REG);

	return 0;
}

static int sun4i_mdio_reset(struct mii_bus *bus)
{
	return 0;
}

static int sun4i_mdio_probe(struct vmm_device *pdev,
			    const struct vmm_devtree_nodeid *devid)
{
	struct device_node *np = pdev->node;
	struct mii_bus *bus;
	struct sun4i_mdio_data *data;
	int ret, i;
	virtual_addr_t  reg_addr;

	bus = mdiobus_alloc_size(sizeof(*data));
	if (!bus)
		return -ENOMEM;

	bus->name = "sun4i_mii_bus";
	bus->read = &sun4i_mdio_read;
	bus->write = &sun4i_mdio_write;
	bus->reset = &sun4i_mdio_reset;
	snprintf(bus->id, MII_BUS_ID_SIZE, "%s-mii", dev_name(pdev));
	bus->parent = pdev;

#if 0
	bus->irq = devm_kzalloc(&pdev->dev, sizeof(int) * PHY_MAX_ADDR,
			GFP_KERNEL);
#endif
	bus->irq = kzalloc(sizeof(int) * PHY_MAX_ADDR, GFP_KERNEL);

	if (!bus->irq) {
		ret = -ENOMEM;
		goto err_out_free_mdiobus;
	}

	for (i = 0; i < PHY_MAX_ADDR; i++)
		bus->irq[i] = PHY_POLL;

	data = bus->priv;
#if 0
	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	data->membase = devm_ioremap_resource(&pdev->dev, res);
	if (IS_ERR(data->membase)) {
		ret = PTR_ERR(data->membase);
		goto err_out_free_mdiobus;
	}
#endif
	if ((ret = vmm_devtree_request_regmap(np, &reg_addr, 0,
						"Sun4i MDIO"))) {
		vmm_printf("%s: Failed to ioremap\n", __func__);
		return -ENOMEM;
	}

	data->membase = (void *) reg_addr;

#if 0
	data->regulator = devm_regulator_get(&pdev->dev, "phy");
#endif
	data->regulator = devm_regulator_get(pdev, "phy");

	if (IS_ERR(data->regulator)) {
		if (PTR_ERR(data->regulator) == -EPROBE_DEFER)
			return -EPROBE_DEFER;

		dev_info(pdev, "no regulator found\n");
	} else {
		ret = regulator_enable(data->regulator);
		if (ret)
			goto err_out_free_mdiobus;
	}

	ret = of_mdiobus_register(bus, np);
	if (ret < 0)
		goto err_out_disable_regulator;

	platform_set_drvdata(pdev, bus);

	return 0;

err_out_disable_regulator:
	regulator_disable(data->regulator);
err_out_free_mdiobus:
	mdiobus_free(bus);
	return ret;
}

static int sun4i_mdio_remove(struct vmm_device *pdev)
{
	struct mii_bus *bus = platform_get_drvdata(pdev);

	mdiobus_unregister(bus);
	/* since we have not used devm_kzalloc to alloc this meomory */
	kfree(bus->irq);
	mdiobus_free(bus);

	return 0;
}

static struct vmm_devtree_nodeid sun4i_mdio_dt_ids[] = {
	{ .compatible = "allwinner,sun4i-mdio" },
        { /* end of list */ },
};

static struct vmm_driver sun4i_mdio_driver = {
	.probe = sun4i_mdio_probe,
	.remove = sun4i_mdio_remove,
	.name = "sun4i-mdio",
	.match_table = sun4i_mdio_dt_ids,
};

static int __init sun4i_mdio_driver_init(void)
{
        return vmm_devdrv_register_driver(&sun4i_mdio_driver);
}

static void __exit sun4i_mdio_driver_exit(void)
{
        vmm_devdrv_unregister_driver(&sun4i_mdio_driver);
}

VMM_DECLARE_MODULE(MODULE_DESC,
		MODULE_AUTHOR,
		MODULE_LICENSE,
		MODULE_IPRIORITY,
		MODULE_INIT,
		MODULE_EXIT);
