/*
* Broadcom UniMAC MDIO bus controller driver
*
* Copyright (C) 2014, Broadcom Corporation
*
* 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/phy.h>
#include <linux/platform_device.h>
#include <linux/sched.h>
#include <linux/module.h>
#include <linux/io.h>
#include <linux/delay.h>
#include <linux/of.h>
#include <linux/of_platform.h>
#include <linux/of_mdio.h>
#define MDIO_CMD 0x00
#define MDIO_START_BUSY (1 << 29)
#define MDIO_READ_FAIL (1 << 28)
#define MDIO_RD (2 << 26)
#define MDIO_WR (1 << 26)
#define MDIO_PMD_SHIFT 21
#define MDIO_PMD_MASK 0x1F
#define MDIO_REG_SHIFT 16
#define MDIO_REG_MASK 0x1F
#define MDIO_CFG 0x04
#define MDIO_C22 (1 << 0)
#define MDIO_C45 0
#define MDIO_CLK_DIV_SHIFT 4
#define MDIO_CLK_DIV_MASK 0x3F
#define MDIO_SUPP_PREAMBLE (1 << 12)
struct unimac_mdio_priv {
struct mii_bus *mii_bus;
void __iomem *base;
};
static inline void unimac_mdio_start(struct unimac_mdio_priv *priv)
{
u32 reg;
reg = __raw_readl(priv->base + MDIO_CMD);
reg |= MDIO_START_BUSY;
__raw_writel(reg, priv->base + MDIO_CMD);
}
static inline unsigned int unimac_mdio_busy(struct unimac_mdio_priv *priv)
{
return __raw_readl(priv->base + MDIO_CMD) & MDIO_START_BUSY;
}
static int unimac_mdio_read(struct mii_bus *bus, int phy_id, int reg)
{
struct unimac_mdio_priv *priv = bus->priv;
unsigned int timeout = 1000;
u32 cmd;
/* Prepare the read operation */
cmd = MDIO_RD | (phy_id << MDIO_PMD_SHIFT) | (reg << MDIO_REG_SHIFT);
__raw_writel(cmd, priv->base + MDIO_CMD);
/* Start MDIO transaction */
unimac_mdio_start(priv);
do {
if (!unimac_mdio_busy(priv))
break;
usleep_range(1000, 2000);
} while (timeout--);
if (!timeout)
return -ETIMEDOUT;
cmd = __raw_readl(priv->base + MDIO_CMD);
/* Some broken devices are known not to release the line during
* turn-around, e.g: Broadcom BCM53125 external switches, so check for
* that condition here and ignore the MDIO controller read failure
* indication.
*/
if (!(bus->phy_ignore_ta_mask & 1 << phy_id) && (cmd & MDIO_READ_FAIL))
return -EIO;
return cmd & 0xffff;
}
static int unimac_mdio_write(struct mii_bus *bus, int phy_id,
int reg, u16 val)
{
struct unimac_mdio_priv *priv = bus->priv;
unsigned int timeout = 1000;
u32 cmd;
/* Prepare the write operation */
cmd = MDIO_WR | (phy_id << MDIO_PMD_SHIFT) |
(reg << MDIO_REG_SHIFT) | (0xffff & val);
__raw_writel(cmd, priv->base + MDIO_CMD);
unimac_mdio_start(priv);
do {
if (!unimac_mdio_busy(priv))
break;
usleep_range(1000, 2000);
} while (timeout--);
if (!timeout)
return -ETIMEDOUT;
return 0;
}
/* Workaround for integrated BCM7xxx Gigabit PHYs which have a problem with
* their internal MDIO management controller making them fail to successfully
* be read from or written to for the first transaction. We insert a dummy
* BMSR read here to make sure that phy_get_device() and get_phy_id() can
* correctly read the PHY MII_PHYSID1/2 registers and successfully register a
* PHY device for this peripheral.
*
* Once the PHY driver is registered, we can workaround subsequent reads from
* there (e.g: during system-wide power management).
*
* bus->reset is invoked before mdiobus_scan during mdiobus_register and is
* therefore the right location to stick that workaround. Since we do not want
* to read from non-existing PHYs, we either use bus->phy_mask or do a manual
* Device Tree scan to limit the search area.
*/
static int unimac_mdio_reset(struct mii_bus *bus)
{
struct device_node *np = bus->dev.of_node;
struct device_node *child;
u32 read_mask = 0;
int addr;
if (!np) {
read_mask = ~bus->phy_mask;
} else {
for_each_available_child_of_node(np, child) {
addr = of_mdio_parse_addr(&bus->dev, child);
if (addr < 0)
continue;
read_mask |= 1 << addr;
}
}
for (addr = 0; addr < PHY_MAX_ADDR; addr++) {
if (read_mask & 1 << addr)
mdiobus_read(bus, addr, MII_BMSR);
}
return 0;
}
static int unimac_mdio_probe(struct platform_device *pdev)
{
struct unimac_mdio_priv *priv;
struct device_node *np;
struct mii_bus *bus;
struct resource *r;
int ret;
np = pdev->dev.of_node;
priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
if (!priv)
return -ENOMEM;
r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
/* Just ioremap, as this MDIO block is usually integrated into an
* Ethernet MAC controller register range
*/
priv->base = devm_ioremap(&pdev->dev, r->start, resource_size(r));
if (!priv->base) {
dev_err(&pdev->dev, "failed to remap register\n");
return -ENOMEM;
}
priv->mii_bus = mdiobus_alloc();
if (!priv->mii_bus)
return -ENOMEM;
bus = priv->mii_bus;
bus->priv = priv;
bus->name = "unimac MII bus";
bus->parent = &pdev->dev;
bus->read = unimac_mdio_read;
bus->write = unimac_mdio_write;
bus->reset = unimac_mdio_reset;
snprintf(bus->id, MII_BUS_ID_SIZE, "%s", pdev->name);
ret = of_mdiobus_register(bus, np);
if (ret) {
dev_err(&pdev->dev, "MDIO bus registration failed\n");
goto out_mdio_free;
}
platform_set_drvdata(pdev, priv);
dev_info(&pdev->dev, "Broadcom UniMAC MDIO bus at 0x%p\n", priv->base);
return 0;
out_mdio_free:
mdiobus_free(bus);
return ret;
}
static int unimac_mdio_remove(struct platform_device *pdev)
{
struct unimac_mdio_priv *priv = platform_get_drvdata(pdev);
mdiobus_unregister(priv->mii_bus);
mdiobus_free(priv->mii_bus);
return 0;
}
static const struct of_device_id unimac_mdio_ids[] = {
{ .compatible = "brcm,genet-mdio-v4", },
{ .compatible = "brcm,genet-mdio-v3", },
{ .compatible = "brcm,genet-mdio-v2", },
{ .compatible = "brcm,genet-mdio-v1", },
{ .compatible = "brcm,unimac-mdio", },
{ /* sentinel */ },
};
MODULE_DEVICE_TABLE(of, unimac_mdio_ids);
static struct platform_driver unimac_mdio_driver = {
.driver = {
.name = "unimac-mdio",
.of_match_table = unimac_mdio_ids,
},
.probe = unimac_mdio_probe,
.remove = unimac_mdio_remove,
};
module_platform_driver(unimac_mdio_driver);
MODULE_AUTHOR("Broadcom Corporation");
MODULE_DESCRIPTION("Broadcom UniMAC MDIO bus controller");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:unimac-mdio");
