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/*
* Driver for the MDIO interface of Marvell network interfaces.
*
* Since the MDIO interface of Marvell network interfaces is shared
* between all network interfaces, having a single driver allows to
* handle concurrent accesses properly (you may have four Ethernet
* ports, but they in fact share the same SMI interface to access the
* MDIO bus). Moreover, this MDIO interface code is similar between
* the mv643xx_eth driver and the mvneta driver. For now, it is only
* used by the mvneta driver, but it could later be used by the
* mv643xx_eth driver as well.
*
* Copyright (C) 2012 Marvell
*
* Thomas Petazzoni <thomas.petazzoni@free-electrons.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/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/phy.h>
#include <linux/of_address.h>
#include <linux/of_mdio.h>
#include <linux/platform_device.h>
#include <linux/delay.h>
#define MVMDIO_SMI_DATA_SHIFT 0
#define MVMDIO_SMI_PHY_ADDR_SHIFT 16
#define MVMDIO_SMI_PHY_REG_SHIFT 21
#define MVMDIO_SMI_READ_OPERATION BIT(26)
#define MVMDIO_SMI_WRITE_OPERATION 0
#define MVMDIO_SMI_READ_VALID BIT(27)
#define MVMDIO_SMI_BUSY BIT(28)
struct orion_mdio_dev {
struct mutex lock;
void __iomem *smireg;
};
/* Wait for the SMI unit to be ready for another operation
*/
static int orion_mdio_wait_ready(struct mii_bus *bus)
{
struct orion_mdio_dev *dev = bus->priv;
int count;
u32 val;
count = 0;
while (1) {
val = readl(dev->smireg);
if (!(val & MVMDIO_SMI_BUSY))
break;
if (count > 100) {
dev_err(bus->parent, "Timeout: SMI busy for too long\n");
return -ETIMEDOUT;
}
udelay(10);
count++;
}
return 0;
}
static int orion_mdio_read(struct mii_bus *bus, int mii_id,
int regnum)
{
struct orion_mdio_dev *dev = bus->priv;
int count;
u32 val;
int ret;
mutex_lock(&dev->lock);
ret = orion_mdio_wait_ready(bus);
if (ret < 0) {
mutex_unlock(&dev->lock);
return ret;
}
writel(((mii_id << MVMDIO_SMI_PHY_ADDR_SHIFT) |
(regnum << MVMDIO_SMI_PHY_REG_SHIFT) |
MVMDIO_SMI_READ_OPERATION),
dev->smireg);
/* Wait for the value to become available */
count = 0;
while (1) {
val = readl(dev->smireg);
if (val & MVMDIO_SMI_READ_VALID)
break;
if (count > 100) {
dev_err(bus->parent, "Timeout when reading PHY\n");
mutex_unlock(&dev->lock);
return -ETIMEDOUT;
}
udelay(10);
count++;
}
mutex_unlock(&dev->lock);
return val & 0xFFFF;
}
static int orion_mdio_write(struct mii_bus *bus, int mii_id,
int regnum, u16 value)
{
struct orion_mdio_dev *dev = bus->priv;
int ret;
mutex_lock(&dev->lock);
ret = orion_mdio_wait_ready(bus);
if (ret < 0) {
mutex_unlock(&dev->lock);
return ret;
}
writel(((mii_id << MVMDIO_SMI_PHY_ADDR_SHIFT) |
(regnum << MVMDIO_SMI_PHY_REG_SHIFT) |
MVMDIO_SMI_WRITE_OPERATION |
(value << MVMDIO_SMI_DATA_SHIFT)),
dev->smireg);
mutex_unlock(&dev->lock);
return 0;
}
static int orion_mdio_reset(struct mii_bus *bus)
{
return 0;
}
static int orion_mdio_probe(struct platform_device *pdev)
{
struct device_node *np = pdev->dev.of_node;
struct mii_bus *bus;
struct orion_mdio_dev *dev;
int i, ret;
bus = mdiobus_alloc_size(sizeof(struct orion_mdio_dev));
if (!bus) {
dev_err(&pdev->dev, "Cannot allocate MDIO bus\n");
return -ENOMEM;
}
bus->name = "orion_mdio_bus";
bus->read = orion_mdio_read;
bus->write = orion_mdio_write;
bus->reset = orion_mdio_reset;
snprintf(bus->id, MII_BUS_ID_SIZE, "%s-mii",
dev_name(&pdev->dev));
bus->parent = &pdev->dev;
bus->irq = kmalloc(sizeof(int) * PHY_MAX_ADDR, GFP_KERNEL);
if (!bus->irq) {
mdiobus_free(bus);
return -ENOMEM;
}
for (i = 0; i < PHY_MAX_ADDR; i++)
bus->irq[i] = PHY_POLL;
dev = bus->priv;
dev->smireg = of_iomap(pdev->dev.of_node, 0);
if (!dev->smireg) {
dev_err(&pdev->dev, "No SMI register address given in DT\n");
kfree(bus->irq);
mdiobus_free(bus);
return -ENODEV;
}
mutex_init(&dev->lock);
ret = of_mdiobus_register(bus, np);
if (ret < 0) {
dev_err(&pdev->dev, "Cannot register MDIO bus (%d)\n", ret);
iounmap(dev->smireg);
kfree(bus->irq);
mdiobus_free(bus);
return ret;
}
platform_set_drvdata(pdev, bus);
return 0;
}
static int orion_mdio_remove(struct platform_device *pdev)
{
struct mii_bus *bus = platform_get_drvdata(pdev);
mdiobus_unregister(bus);
kfree(bus->irq);
mdiobus_free(bus);
return 0;
}
static const struct of_device_id orion_mdio_match[] = {
{ .compatible = "marvell,orion-mdio" },
{ }
};
MODULE_DEVICE_TABLE(of, orion_mdio_match);
static struct platform_driver orion_mdio_driver = {
.probe = orion_mdio_probe,
.remove = orion_mdio_remove,
.driver = {
.name = "orion-mdio",
.of_match_table = orion_mdio_match,
},
};
module_platform_driver(orion_mdio_driver);
MODULE_DESCRIPTION("Marvell MDIO interface driver");
MODULE_AUTHOR("Thomas Petazzoni <thomas.petazzoni@free-electrons.com>");
MODULE_LICENSE("GPL");
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