drivers/net/ethernet/marvell/mvmdio.c - kernel/bruno - Git at Google

 /*
  * 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). This driver is currently used by the mvneta and
  * mv643xx_eth drivers.
  *
  * 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/kernel.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
 #include <linux/phy.h>
 #include <linux/interrupt.h>
 #include <linux/platform_device.h>
 #include <linux/delay.h>
 #include <linux/io.h>
 #include <linux/clk.h>
 #include <linux/of_mdio.h>
 #include <linux/sched.h>
 #include <linux/wait.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)
 #define MVMDIO_ERR_INT_CAUSE		   0x007C
 #define  MVMDIO_ERR_INT_SMI_DONE	   0x00000010
 #define MVMDIO_ERR_INT_MASK		   0x0080

 /*
  * SMI Timeout measurements:
  * - Kirkwood 88F6281 (Globalscale Dreamplug): 45us to 95us (Interrupt)
  * - Armada 370       (Globalscale Mirabox):   41us to 43us (Polled)
  */
 #define MVMDIO_SMI_TIMEOUT		   1000 /* 1000us = 1ms */
 #define MVMDIO_SMI_POLL_INTERVAL_MIN	   45
 #define MVMDIO_SMI_POLL_INTERVAL_MAX	   55

 struct orion_mdio_dev {
 	struct mutex lock;
 	void __iomem *regs;
 	struct clk *clk;
 	/*
 	 * If we have access to the error interrupt pin (which is
 	 * somewhat misnamed as it not only reflects internal errors
 	 * but also reflects SMI completion), use that to wait for
 	 * SMI access completion instead of polling the SMI busy bit.
 	 */
 	int err_interrupt;
 	wait_queue_head_t smi_busy_wait;
 };

 static int orion_mdio_smi_is_done(struct orion_mdio_dev *dev)
 {
 	return !(readl(dev->regs) & MVMDIO_SMI_BUSY);
 }

 /* 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;
 	unsigned long timeout = usecs_to_jiffies(MVMDIO_SMI_TIMEOUT);
 	unsigned long end = jiffies + timeout;
 	int timedout = 0;

 	while (1) {
 	        if (orion_mdio_smi_is_done(dev))
 			return 0;
 	        else if (timedout)
 			break;

 	        if (dev->err_interrupt <= 0) {
 			usleep_range(MVMDIO_SMI_POLL_INTERVAL_MIN,
 				     MVMDIO_SMI_POLL_INTERVAL_MAX);

 			if (time_is_before_jiffies(end))
 				++timedout;
 	        } else {
 			/* wait_event_timeout does not guarantee a delay of at
 			 * least one whole jiffie, so timeout must be no less
 			 * than two.
 			 */
 			if (timeout < 2)
 				timeout = 2;
 			wait_event_timeout(dev->smi_busy_wait,
 				           orion_mdio_smi_is_done(dev),
 				           timeout);

 			++timedout;
 	        }
 	}

 	dev_err(bus->parent, "Timeout: SMI busy for too long\n");
 	return  -ETIMEDOUT;
 }

 static int orion_mdio_read(struct mii_bus *bus, int mii_id,
 			   int regnum)
 {
 	struct orion_mdio_dev *dev = bus->priv;
 	u32 val;
 	int ret;

 	mutex_lock(&dev->lock);

 	ret = orion_mdio_wait_ready(bus);
 	if (ret < 0)
 		goto out;

 	writel(((mii_id << MVMDIO_SMI_PHY_ADDR_SHIFT) |
 		(regnum << MVMDIO_SMI_PHY_REG_SHIFT)  |
 		MVMDIO_SMI_READ_OPERATION),
 	       dev->regs);

 	ret = orion_mdio_wait_ready(bus);
 	if (ret < 0)
 		goto out;

 	val = readl(dev->regs);
 	if (!(val & MVMDIO_SMI_READ_VALID)) {
 		dev_err(bus->parent, "SMI bus read not valid\n");
 		ret = -ENODEV;
 		goto out;
 	}

 	ret = val & 0xFFFF;
 out:
 	mutex_unlock(&dev->lock);
 	return ret;
 }

 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)
 		goto out;

 	writel(((mii_id << MVMDIO_SMI_PHY_ADDR_SHIFT) |
 		(regnum << MVMDIO_SMI_PHY_REG_SHIFT)  |
 		MVMDIO_SMI_WRITE_OPERATION            |
 		(value << MVMDIO_SMI_DATA_SHIFT)),
 	       dev->regs);

 out:
 	mutex_unlock(&dev->lock);
 	return ret;
 }

 static irqreturn_t orion_mdio_err_irq(int irq, void *dev_id)
 {
 	struct orion_mdio_dev *dev = dev_id;

 	if (readl(dev->regs + MVMDIO_ERR_INT_CAUSE) &
 			MVMDIO_ERR_INT_SMI_DONE) {
 		writel(~MVMDIO_ERR_INT_SMI_DONE,
 				dev->regs + MVMDIO_ERR_INT_CAUSE);
 		wake_up(&dev->smi_busy_wait);
 		return IRQ_HANDLED;
 	}

 	return IRQ_NONE;
 }

 static int orion_mdio_probe(struct platform_device *pdev)
 {
 	struct resource *r;
 	struct mii_bus *bus;
 	struct orion_mdio_dev *dev;
 	int i, ret;

 	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	if (!r) {
 		dev_err(&pdev->dev, "No SMI register address given\n");
 		return -ENODEV;
 	}

 	bus = devm_mdiobus_alloc_size(&pdev->dev,
 				      sizeof(struct orion_mdio_dev));
 	if (!bus)
 		return -ENOMEM;

 	bus->name = "orion_mdio_bus";
 	bus->read = orion_mdio_read;
 	bus->write = orion_mdio_write;
 	snprintf(bus->id, MII_BUS_ID_SIZE, "%s-mii",
 		 dev_name(&pdev->dev));
 	bus->parent = &pdev->dev;

 	bus->irq = devm_kmalloc_array(&pdev->dev, PHY_MAX_ADDR, sizeof(int),
 				      GFP_KERNEL);
 	if (!bus->irq)
 		return -ENOMEM;

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

 	dev = bus->priv;
 	dev->regs = devm_ioremap(&pdev->dev, r->start, resource_size(r));
 	if (!dev->regs) {
 		dev_err(&pdev->dev, "Unable to remap SMI register\n");
 		ret = -ENODEV;
 		goto out_mdio;
 	}

 	init_waitqueue_head(&dev->smi_busy_wait);

 	dev->clk = devm_clk_get(&pdev->dev, NULL);
 	if (!IS_ERR(dev->clk))
 		clk_prepare_enable(dev->clk);

 	dev->err_interrupt = platform_get_irq(pdev, 0);
 	if (dev->err_interrupt > 0) {
 		ret = devm_request_irq(&pdev->dev, dev->err_interrupt,
 					orion_mdio_err_irq,
 					IRQF_SHARED, pdev->name, dev);
 		if (ret)
 			goto out_mdio;

 		writel(MVMDIO_ERR_INT_SMI_DONE,
 			dev->regs + MVMDIO_ERR_INT_MASK);

 	} else if (dev->err_interrupt == -EPROBE_DEFER) {
 		return -EPROBE_DEFER;
 	}

 	mutex_init(&dev->lock);

 	if (pdev->dev.of_node)
 		ret = of_mdiobus_register(bus, pdev->dev.of_node);
 	else
 		ret = mdiobus_register(bus);
 	if (ret < 0) {
 		dev_err(&pdev->dev, "Cannot register MDIO bus (%d)\n", ret);
 		goto out_mdio;
 	}

 	platform_set_drvdata(pdev, bus);

 	return 0;

 out_mdio:
 	if (!IS_ERR(dev->clk))
 		clk_disable_unprepare(dev->clk);
 	return ret;
 }

 static int orion_mdio_remove(struct platform_device *pdev)
 {
 	struct mii_bus *bus = platform_get_drvdata(pdev);
 	struct orion_mdio_dev *dev = bus->priv;

 	writel(0, dev->regs + MVMDIO_ERR_INT_MASK);
 	mdiobus_unregister(bus);
 	if (!IS_ERR(dev->clk))
 		clk_disable_unprepare(dev->clk);

 	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");
 MODULE_ALIAS("platform:orion-mdio");
	/*
	* 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). This driver is currently used by the mvneta and
	* mv643xx_eth drivers.
	*
	* 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/kernel.h>
	#include <linux/module.h>
	#include <linux/mutex.h>
	#include <linux/phy.h>
	#include <linux/interrupt.h>
	#include <linux/platform_device.h>
	#include <linux/delay.h>
	#include <linux/io.h>
	#include <linux/clk.h>
	#include <linux/of_mdio.h>
	#include <linux/sched.h>
	#include <linux/wait.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)
	#define MVMDIO_ERR_INT_CAUSE 0x007C
	#define MVMDIO_ERR_INT_SMI_DONE 0x00000010
	#define MVMDIO_ERR_INT_MASK 0x0080

	/*
	* SMI Timeout measurements:
	* - Kirkwood 88F6281 (Globalscale Dreamplug): 45us to 95us (Interrupt)
	* - Armada 370 (Globalscale Mirabox): 41us to 43us (Polled)
	*/
	#define MVMDIO_SMI_TIMEOUT 1000 /* 1000us = 1ms */
	#define MVMDIO_SMI_POLL_INTERVAL_MIN 45
	#define MVMDIO_SMI_POLL_INTERVAL_MAX 55

	struct orion_mdio_dev {
	struct mutex lock;
	void __iomem *regs;
	struct clk *clk;
	/*
	* If we have access to the error interrupt pin (which is
	* somewhat misnamed as it not only reflects internal errors
	* but also reflects SMI completion), use that to wait for
	* SMI access completion instead of polling the SMI busy bit.
	*/
	int err_interrupt;
	wait_queue_head_t smi_busy_wait;
	};

	static int orion_mdio_smi_is_done(struct orion_mdio_dev *dev)
	{
	return !(readl(dev->regs) & MVMDIO_SMI_BUSY);
	}

	/* 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;
	unsigned long timeout = usecs_to_jiffies(MVMDIO_SMI_TIMEOUT);
	unsigned long end = jiffies + timeout;
	int timedout = 0;

	while (1) {
	if (orion_mdio_smi_is_done(dev))
	return 0;
	else if (timedout)
	break;

	if (dev->err_interrupt <= 0) {
	usleep_range(MVMDIO_SMI_POLL_INTERVAL_MIN,
	MVMDIO_SMI_POLL_INTERVAL_MAX);

	if (time_is_before_jiffies(end))
	++timedout;
	} else {
	/* wait_event_timeout does not guarantee a delay of at
	* least one whole jiffie, so timeout must be no less
	* than two.
	*/
	if (timeout < 2)
	timeout = 2;
	wait_event_timeout(dev->smi_busy_wait,
	orion_mdio_smi_is_done(dev),
	timeout);

	++timedout;
	}
	}

	dev_err(bus->parent, "Timeout: SMI busy for too long\n");
	return -ETIMEDOUT;
	}

	static int orion_mdio_read(struct mii_bus *bus, int mii_id,
	int regnum)
	{
	struct orion_mdio_dev *dev = bus->priv;
	u32 val;
	int ret;

	mutex_lock(&dev->lock);

	ret = orion_mdio_wait_ready(bus);
	if (ret < 0)
	goto out;

	writel(((mii_id << MVMDIO_SMI_PHY_ADDR_SHIFT) \|
	(regnum << MVMDIO_SMI_PHY_REG_SHIFT) \|
	MVMDIO_SMI_READ_OPERATION),
	dev->regs);

	ret = orion_mdio_wait_ready(bus);
	if (ret < 0)
	goto out;

	val = readl(dev->regs);
	if (!(val & MVMDIO_SMI_READ_VALID)) {
	dev_err(bus->parent, "SMI bus read not valid\n");
	ret = -ENODEV;
	goto out;
	}

	ret = val & 0xFFFF;
	out:
	mutex_unlock(&dev->lock);
	return ret;
	}

	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)
	goto out;

	writel(((mii_id << MVMDIO_SMI_PHY_ADDR_SHIFT) \|
	(regnum << MVMDIO_SMI_PHY_REG_SHIFT) \|
	MVMDIO_SMI_WRITE_OPERATION \|
	(value << MVMDIO_SMI_DATA_SHIFT)),
	dev->regs);

	out:
	mutex_unlock(&dev->lock);
	return ret;
	}

	static irqreturn_t orion_mdio_err_irq(int irq, void *dev_id)
	{
	struct orion_mdio_dev *dev = dev_id;

	if (readl(dev->regs + MVMDIO_ERR_INT_CAUSE) &
	MVMDIO_ERR_INT_SMI_DONE) {
	writel(~MVMDIO_ERR_INT_SMI_DONE,
	dev->regs + MVMDIO_ERR_INT_CAUSE);
	wake_up(&dev->smi_busy_wait);
	return IRQ_HANDLED;
	}

	return IRQ_NONE;
	}

	static int orion_mdio_probe(struct platform_device *pdev)
	{
	struct resource *r;
	struct mii_bus *bus;
	struct orion_mdio_dev *dev;
	int i, ret;

	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!r) {
	dev_err(&pdev->dev, "No SMI register address given\n");
	return -ENODEV;
	}

	bus = devm_mdiobus_alloc_size(&pdev->dev,
	sizeof(struct orion_mdio_dev));
	if (!bus)
	return -ENOMEM;

	bus->name = "orion_mdio_bus";
	bus->read = orion_mdio_read;
	bus->write = orion_mdio_write;
	snprintf(bus->id, MII_BUS_ID_SIZE, "%s-mii",
	dev_name(&pdev->dev));
	bus->parent = &pdev->dev;

	bus->irq = devm_kmalloc_array(&pdev->dev, PHY_MAX_ADDR, sizeof(int),
	GFP_KERNEL);
	if (!bus->irq)
	return -ENOMEM;

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

	dev = bus->priv;
	dev->regs = devm_ioremap(&pdev->dev, r->start, resource_size(r));
	if (!dev->regs) {
	dev_err(&pdev->dev, "Unable to remap SMI register\n");
	ret = -ENODEV;
	goto out_mdio;
	}

	init_waitqueue_head(&dev->smi_busy_wait);

	dev->clk = devm_clk_get(&pdev->dev, NULL);
	if (!IS_ERR(dev->clk))
	clk_prepare_enable(dev->clk);

	dev->err_interrupt = platform_get_irq(pdev, 0);
	if (dev->err_interrupt > 0) {
	ret = devm_request_irq(&pdev->dev, dev->err_interrupt,
	orion_mdio_err_irq,
	IRQF_SHARED, pdev->name, dev);
	if (ret)
	goto out_mdio;

	writel(MVMDIO_ERR_INT_SMI_DONE,
	dev->regs + MVMDIO_ERR_INT_MASK);

	} else if (dev->err_interrupt == -EPROBE_DEFER) {
	return -EPROBE_DEFER;
	}

	mutex_init(&dev->lock);

	if (pdev->dev.of_node)
	ret = of_mdiobus_register(bus, pdev->dev.of_node);
	else
	ret = mdiobus_register(bus);
	if (ret < 0) {
	dev_err(&pdev->dev, "Cannot register MDIO bus (%d)\n", ret);
	goto out_mdio;
	}

	platform_set_drvdata(pdev, bus);

	return 0;

	out_mdio:
	if (!IS_ERR(dev->clk))
	clk_disable_unprepare(dev->clk);
	return ret;
	}

	static int orion_mdio_remove(struct platform_device *pdev)
	{
	struct mii_bus *bus = platform_get_drvdata(pdev);
	struct orion_mdio_dev *dev = bus->priv;

	writel(0, dev->regs + MVMDIO_ERR_INT_MASK);
	mdiobus_unregister(bus);
	if (!IS_ERR(dev->clk))
	clk_disable_unprepare(dev->clk);

	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");
	MODULE_ALIAS("platform:orion-mdio");