/*
   * Fixed MDIO bus (MDIO bus emulation with fixed PHYs)
   *
   * Author: Vitaly Bordug <vbordug@ru.mvista.com>
   *         Anton Vorontsov <avorontsov@ru.mvista.com>
   *
   * Copyright (c) 2006-2007 MontaVista Software, Inc.
   *
   * This program is free software; you can redistribute  it and/or modify it
   * under  the terms of  the GNU General  Public License as published by the
   * Free Software Foundation;  either version 2 of the  License, or (at your
   * option) any later version.
   */
  
  #include <linux/kernel.h>
  #include <linux/module.h>
  #include <linux/platform_device.h>
  #include <linux/list.h>
  #include <linux/mii.h>
  #include <linux/phy.h>
  #include <linux/phy_fixed.h>
  #include <linux/err.h>
  #include <linux/slab.h>
  #include <linux/of.h>
  #include <linux/gpio.h>
  
  #define MII_REGS_NUM 29
  
  struct fixed_mdio_bus {
  	int irqs[PHY_MAX_ADDR];
  	struct mii_bus *mii_bus;
  	struct list_head phys;
  };
  
  struct fixed_phy {
  	int addr;
  	u16 regs[MII_REGS_NUM];
  	struct phy_device *phydev;
  	struct fixed_phy_status status;
  	int (*link_update)(struct net_device *, struct fixed_phy_status *);
  	struct list_head node;
  	int link_gpio;
  };
  
  static struct platform_device *pdev;
  static struct fixed_mdio_bus platform_fmb = {
  	.phys = LIST_HEAD_INIT(platform_fmb.phys),
  };
  
  static int fixed_phy_update_regs(struct fixed_phy *fp)
  {
  	u16 bmsr = BMSR_ANEGCAPABLE;
  	u16 bmcr = 0;
  	u16 lpagb = 0;
  	u16 lpa = 0;
  
  	if (gpio_is_valid(fp->link_gpio))
  		fp->status.link = !!gpio_get_value_cansleep(fp->link_gpio);
  
  	if (fp->status.duplex) {
  		switch (fp->status.speed) {
  		case 1000:
  			bmsr |= BMSR_ESTATEN;
  			break;
  		case 100:
  			bmsr |= BMSR_100FULL;
  			break;
  		case 10:
  			bmsr |= BMSR_10FULL;
  			break;
  		default:
  			break;
  		}
  	} else {
  		switch (fp->status.speed) {
  		case 1000:
  			bmsr |= BMSR_ESTATEN;
  			break;
  		case 100:
  			bmsr |= BMSR_100HALF;
  			break;
  		case 10:
  			bmsr |= BMSR_10HALF;
  			break;
  		default:
  			break;
  		}
  	}
  
  	if (fp->status.link) {
  		bmsr |= BMSR_LSTATUS | BMSR_ANEGCOMPLETE;
  
  		if (fp->status.duplex) {
  			bmcr |= BMCR_FULLDPLX;
  
  			switch (fp->status.speed) {
  			case 1000:
  				bmcr |= BMCR_SPEED1000;
  				lpagb |= LPA_1000FULL;
  				break;
  			case 100:
  				bmcr |= BMCR_SPEED100;
  				lpa |= LPA_100FULL;
  				break;
  			case 10:
  				lpa |= LPA_10FULL;
  				break;
  			default:
  				pr_warn("fixed phy: unknown speed
  ");
  				return -EINVAL;
  			}
  		} else {
  			switch (fp->status.speed) {
  			case 1000:
  				bmcr |= BMCR_SPEED1000;
  				lpagb |= LPA_1000HALF;
  				break;
  			case 100:
  				bmcr |= BMCR_SPEED100;
  				lpa |= LPA_100HALF;
  				break;
  			case 10:
  				lpa |= LPA_10HALF;
  				break;
  			default:
  				pr_warn("fixed phy: unknown speed
  ");
  			return -EINVAL;
  			}
  		}
  
  		if (fp->status.pause)
  			lpa |= LPA_PAUSE_CAP;
  
  		if (fp->status.asym_pause)
  			lpa |= LPA_PAUSE_ASYM;
  	}
  
  	fp->regs[MII_PHYSID1] = 0;
  	fp->regs[MII_PHYSID2] = 0;
  
  	fp->regs[MII_BMSR] = bmsr;
  	fp->regs[MII_BMCR] = bmcr;
  	fp->regs[MII_LPA] = lpa;
  	fp->regs[MII_STAT1000] = lpagb;
  
  	return 0;
  }
  
  static int fixed_mdio_read(struct mii_bus *bus, int phy_addr, int reg_num)
  {
  	struct fixed_mdio_bus *fmb = bus->priv;
  	struct fixed_phy *fp;
  
  	if (reg_num >= MII_REGS_NUM)
  		return -1;
  
  	/* We do not support emulating Clause 45 over Clause 22 register reads
  	 * return an error instead of bogus data.
  	 */
  	switch (reg_num) {
  	case MII_MMD_CTRL:
  	case MII_MMD_DATA:
  		return -1;
  	default:
  		break;
  	}
  
  	list_for_each_entry(fp, &fmb->phys, node) {
  		if (fp->addr == phy_addr) {
  			/* Issue callback if user registered it. */
  			if (fp->link_update) {
  				fp->link_update(fp->phydev->attached_dev,
  						&fp->status);
  				fixed_phy_update_regs(fp);
  			}
  			return fp->regs[reg_num];
  		}
  	}
  
  	return 0xFFFF;
  }
  
  static int fixed_mdio_write(struct mii_bus *bus, int phy_addr, int reg_num,
  			    u16 val)
  {
  	return 0;
  }
  
  /*
   * If something weird is required to be done with link/speed,
   * network driver is able to assign a function to implement this.
   * May be useful for PHY's that need to be software-driven.
   */
  int fixed_phy_set_link_update(struct phy_device *phydev,
  			      int (*link_update)(struct net_device *,
  						 struct fixed_phy_status *))
  {
  	struct fixed_mdio_bus *fmb = &platform_fmb;
  	struct fixed_phy *fp;
  
  	if (!phydev || !phydev->bus)
  		return -EINVAL;
  
  	list_for_each_entry(fp, &fmb->phys, node) {
  		if (fp->addr == phydev->addr) {
  			fp->link_update = link_update;
  			fp->phydev = phydev;
  			return 0;
  		}
  	}
  
  	return -ENOENT;
  }
  EXPORT_SYMBOL_GPL(fixed_phy_set_link_update);
  
  int fixed_phy_update_state(struct phy_device *phydev,
  			   const struct fixed_phy_status *status,
  			   const struct fixed_phy_status *changed)
  {
  	struct fixed_mdio_bus *fmb = &platform_fmb;
  	struct fixed_phy *fp;
  
  	if (!phydev || phydev->bus != fmb->mii_bus)
  		return -EINVAL;
  
  	list_for_each_entry(fp, &fmb->phys, node) {
  		if (fp->addr == phydev->addr) {
  #define _UPD(x) if (changed->x) \
  	fp->status.x = status->x
  			_UPD(link);
  			_UPD(speed);
  			_UPD(duplex);
  			_UPD(pause);
  			_UPD(asym_pause);
  #undef _UPD
  			fixed_phy_update_regs(fp);
  			return 0;
  		}
  	}
  
  	return -ENOENT;
  }
  EXPORT_SYMBOL(fixed_phy_update_state);
  
  int fixed_phy_add(unsigned int irq, int phy_addr,
  		  struct fixed_phy_status *status,
  		  int link_gpio)
  {
  	int ret;
  	struct fixed_mdio_bus *fmb = &platform_fmb;
  	struct fixed_phy *fp;
  
  	fp = kzalloc(sizeof(*fp), GFP_KERNEL);
  	if (!fp)
  		return -ENOMEM;
  
  	memset(fp->regs, 0xFF,  sizeof(fp->regs[0]) * MII_REGS_NUM);
  
  	fmb->irqs[phy_addr] = irq;
  
  	fp->addr = phy_addr;
  	fp->status = *status;
  	fp->link_gpio = link_gpio;
  
  	if (gpio_is_valid(fp->link_gpio)) {
  		ret = gpio_request_one(fp->link_gpio, GPIOF_DIR_IN,
  				       "fixed-link-gpio-link");
  		if (ret)
  			goto err_regs;
  	}
  
  	ret = fixed_phy_update_regs(fp);
  	if (ret)
  		goto err_gpio;
  
  	list_add_tail(&fp->node, &fmb->phys);
  
  	return 0;
  
  err_gpio:
  	if (gpio_is_valid(fp->link_gpio))
  		gpio_free(fp->link_gpio);
  err_regs:
  	kfree(fp);
  	return ret;
  }
  EXPORT_SYMBOL_GPL(fixed_phy_add);
  
  void fixed_phy_del(int phy_addr)
  {
  	struct fixed_mdio_bus *fmb = &platform_fmb;
  	struct fixed_phy *fp, *tmp;
  
  	list_for_each_entry_safe(fp, tmp, &fmb->phys, node) {
  		if (fp->addr == phy_addr) {
  			list_del(&fp->node);
  			if (gpio_is_valid(fp->link_gpio))
  				gpio_free(fp->link_gpio);
  			kfree(fp);
  			return;
  		}
  	}
  }
  EXPORT_SYMBOL_GPL(fixed_phy_del);
  
  static int phy_fixed_addr;
  static DEFINE_SPINLOCK(phy_fixed_addr_lock);
  
  struct phy_device *fixed_phy_register(unsigned int irq,
  				      struct fixed_phy_status *status,
  				      int link_gpio,
  				      struct device_node *np)
  {
  	struct fixed_mdio_bus *fmb = &platform_fmb;
  	struct phy_device *phy;
  	int phy_addr;
  	int ret;
  
  	/* Get the next available PHY address, up to PHY_MAX_ADDR */
  	spin_lock(&phy_fixed_addr_lock);
  	if (phy_fixed_addr == PHY_MAX_ADDR) {
  		spin_unlock(&phy_fixed_addr_lock);
  		return ERR_PTR(-ENOSPC);
  	}
  	phy_addr = phy_fixed_addr++;
  	spin_unlock(&phy_fixed_addr_lock);
  
  	ret = fixed_phy_add(irq, phy_addr, status, link_gpio);
  	if (ret < 0)
  		return ERR_PTR(ret);
  
  	phy = get_phy_device(fmb->mii_bus, phy_addr, false);
  	if (!phy || IS_ERR(phy)) {
  		fixed_phy_del(phy_addr);
  		return ERR_PTR(-EINVAL);
  	}
  
  	/* propagate the fixed link values to struct phy_device */
  	phy->link = status->link;
  	if (status->link) {
  		phy->speed = status->speed;
  		phy->duplex = status->duplex;
  		phy->pause = status->pause;
  		phy->asym_pause = status->asym_pause;
  	}
  
  	of_node_get(np);
  	phy->dev.of_node = np;
  	phy->is_pseudo_fixed_link = true;
  
  	switch (status->speed) {
  	case SPEED_1000:
  		phy->supported = PHY_1000BT_FEATURES;
  		break;
  	case SPEED_100:
  		phy->supported = PHY_100BT_FEATURES;
  		break;
  	case SPEED_10:
  	default:
  		phy->supported = PHY_10BT_FEATURES;
  	}
  
  	ret = phy_device_register(phy);
  	if (ret) {
  		phy_device_free(phy);
  		of_node_put(np);
  		fixed_phy_del(phy_addr);
  		return ERR_PTR(ret);
  	}
  
  	return phy;
  }
  EXPORT_SYMBOL_GPL(fixed_phy_register);
  
  static int __init fixed_mdio_bus_init(void)
  {
  	struct fixed_mdio_bus *fmb = &platform_fmb;
  	int ret;
  
  	pdev = platform_device_register_simple("Fixed MDIO bus", 0, NULL, 0);
  	if (IS_ERR(pdev)) {
  		ret = PTR_ERR(pdev);
  		goto err_pdev;
  	}
  
  	fmb->mii_bus = mdiobus_alloc();
  	if (fmb->mii_bus == NULL) {
  		ret = -ENOMEM;
  		goto err_mdiobus_reg;
  	}
  
  	snprintf(fmb->mii_bus->id, MII_BUS_ID_SIZE, "fixed-0");
  	fmb->mii_bus->name = "Fixed MDIO Bus";
  	fmb->mii_bus->priv = fmb;
  	fmb->mii_bus->parent = &pdev->dev;
  	fmb->mii_bus->read = &fixed_mdio_read;
  	fmb->mii_bus->write = &fixed_mdio_write;
  	fmb->mii_bus->irq = fmb->irqs;
  
  	ret = mdiobus_register(fmb->mii_bus);
  	if (ret)
  		goto err_mdiobus_alloc;
  
  	return 0;
  
  err_mdiobus_alloc:
  	mdiobus_free(fmb->mii_bus);
  err_mdiobus_reg:
  	platform_device_unregister(pdev);
  err_pdev:
  	return ret;
  }
  module_init(fixed_mdio_bus_init);
  
  static void __exit fixed_mdio_bus_exit(void)
  {
  	struct fixed_mdio_bus *fmb = &platform_fmb;
  	struct fixed_phy *fp, *tmp;
  
  	mdiobus_unregister(fmb->mii_bus);
  	mdiobus_free(fmb->mii_bus);
  	platform_device_unregister(pdev);
  
  	list_for_each_entry_safe(fp, tmp, &fmb->phys, node) {
  		list_del(&fp->node);
  		kfree(fp);
  	}
  }
  module_exit(fixed_mdio_bus_exit);
  
  MODULE_DESCRIPTION("Fixed MDIO bus (MDIO bus emulation with fixed PHYs)");
  MODULE_AUTHOR("Vitaly Bordug");
  MODULE_LICENSE("GPL");