drivers/uio/uio_pdrv_genirq.c - kernel/skids - Git at Google

 /*
  * drivers/uio/uio_pdrv_genirq.c
  *
  * Userspace I/O platform driver with generic IRQ handling code.
  *
  * Copyright (C) 2008 Magnus Damm
  *
  * Based on uio_pdrv.c by Uwe Kleine-Koenig,
  * Copyright (C) 2008 by Digi International Inc.
  * All rights reserved.
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 as published by
  * the Free Software Foundation.
  */

 #include <linux/platform_device.h>
 #include <linux/uio_driver.h>
 #include <linux/spinlock.h>
 #include <linux/bitops.h>
 #include <linux/interrupt.h>
 #include <linux/stringify.h>
 #include <linux/pm_runtime.h>
 #include <linux/slab.h>

 #define DRIVER_NAME "uio_pdrv_genirq"

 struct uio_pdrv_genirq_platdata {
 	struct uio_info *uioinfo;
 	spinlock_t lock;
 	unsigned long flags;
 	struct platform_device *pdev;
 };

 static int uio_pdrv_genirq_open(struct uio_info *info, struct inode *inode)
 {
 	struct uio_pdrv_genirq_platdata *priv = info->priv;

 	/* Wait until the Runtime PM code has woken up the device */
 	pm_runtime_get_sync(&priv->pdev->dev);
 	return 0;
 }

 static int uio_pdrv_genirq_release(struct uio_info *info, struct inode *inode)
 {
 	struct uio_pdrv_genirq_platdata *priv = info->priv;

 	/* Tell the Runtime PM code that the device has become idle */
 	pm_runtime_put_sync(&priv->pdev->dev);
 	return 0;
 }

 static irqreturn_t uio_pdrv_genirq_handler(int irq, struct uio_info *dev_info)
 {
 	struct uio_pdrv_genirq_platdata *priv = dev_info->priv;

 	/* Just disable the interrupt in the interrupt controller, and
 	 * remember the state so we can allow user space to enable it later.
 	 */

 	if (!test_and_set_bit(0, &priv->flags))
 		disable_irq_nosync(irq);

 	return IRQ_HANDLED;
 }

 static int uio_pdrv_genirq_irqcontrol(struct uio_info *dev_info, s32 irq_on)
 {
 	struct uio_pdrv_genirq_platdata *priv = dev_info->priv;
 	unsigned long flags;

 	/* Allow user space to enable and disable the interrupt
 	 * in the interrupt controller, but keep track of the
 	 * state to prevent per-irq depth damage.
 	 *
 	 * Serialize this operation to support multiple tasks.
 	 */

 	spin_lock_irqsave(&priv->lock, flags);
 	if (irq_on) {
 		if (test_and_clear_bit(0, &priv->flags))
 			enable_irq(dev_info->irq);
 	} else {
 		if (!test_and_set_bit(0, &priv->flags))
 			disable_irq(dev_info->irq);
 	}
 	spin_unlock_irqrestore(&priv->lock, flags);

 	return 0;
 }

 static int uio_pdrv_genirq_probe(struct platform_device *pdev)
 {
 	struct uio_info *uioinfo = pdev->dev.platform_data;
 	struct uio_pdrv_genirq_platdata *priv;
 	struct uio_mem *uiomem;
 	int ret = -EINVAL;
 	int i;

 	if (!uioinfo || !uioinfo->name || !uioinfo->version) {
 		dev_err(&pdev->dev, "missing platform_data\n");
 		goto bad0;
 	}

 	if (uioinfo->handler || uioinfo->irqcontrol ||
 	    uioinfo->irq_flags & IRQF_SHARED) {
 		dev_err(&pdev->dev, "interrupt configuration error\n");
 		goto bad0;
 	}

 	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
 	if (!priv) {
 		ret = -ENOMEM;
 		dev_err(&pdev->dev, "unable to kmalloc\n");
 		goto bad0;
 	}

 	priv->uioinfo = uioinfo;
 	spin_lock_init(&priv->lock);
 	priv->flags = 0; /* interrupt is enabled to begin with */
 	priv->pdev = pdev;

 	uiomem = &uioinfo->mem[0];

 	for (i = 0; i < pdev->num_resources; ++i) {
 		struct resource *r = &pdev->resource[i];

 		if (r->flags != IORESOURCE_MEM)
 			continue;

 		if (uiomem >= &uioinfo->mem[MAX_UIO_MAPS]) {
 			dev_warn(&pdev->dev, "device has more than "
 					__stringify(MAX_UIO_MAPS)
 					" I/O memory resources.\n");
 			break;
 		}

 		uiomem->memtype = UIO_MEM_PHYS;
 		uiomem->addr = r->start;
 		uiomem->size = r->end - r->start + 1;
 		++uiomem;
 	}

 	while (uiomem < &uioinfo->mem[MAX_UIO_MAPS]) {
 		uiomem->size = 0;
 		++uiomem;
 	}

 	/* This driver requires no hardware specific kernel code to handle
 	 * interrupts. Instead, the interrupt handler simply disables the
 	 * interrupt in the interrupt controller. User space is responsible
 	 * for performing hardware specific acknowledge and re-enabling of
 	 * the interrupt in the interrupt controller.
 	 *
 	 * Interrupt sharing is not supported.
 	 */

 	uioinfo->irq_flags |= IRQF_DISABLED;
 	uioinfo->handler = uio_pdrv_genirq_handler;
 	uioinfo->irqcontrol = uio_pdrv_genirq_irqcontrol;
 	uioinfo->open = uio_pdrv_genirq_open;
 	uioinfo->release = uio_pdrv_genirq_release;
 	uioinfo->priv = priv;

 	/* Enable Runtime PM for this device:
 	 * The device starts in suspended state to allow the hardware to be
 	 * turned off by default. The Runtime PM bus code should power on the
 	 * hardware and enable clocks at open().
 	 */
 	pm_runtime_enable(&pdev->dev);

 	ret = uio_register_device(&pdev->dev, priv->uioinfo);
 	if (ret) {
 		dev_err(&pdev->dev, "unable to register uio device\n");
 		goto bad1;
 	}

 	platform_set_drvdata(pdev, priv);
 	return 0;
  bad1:
 	kfree(priv);
 	pm_runtime_disable(&pdev->dev);
  bad0:
 	return ret;
 }

 static int uio_pdrv_genirq_remove(struct platform_device *pdev)
 {
 	struct uio_pdrv_genirq_platdata *priv = platform_get_drvdata(pdev);

 	uio_unregister_device(priv->uioinfo);
 	pm_runtime_disable(&pdev->dev);
 	kfree(priv);
 	return 0;
 }

 static int uio_pdrv_genirq_runtime_nop(struct device *dev)
 {
 	/* Runtime PM callback shared between ->runtime_suspend()
 	 * and ->runtime_resume(). Simply returns success.
 	 *
 	 * In this driver pm_runtime_get_sync() and pm_runtime_put_sync()
 	 * are used at open() and release() time. This allows the
 	 * Runtime PM code to turn off power to the device while the
 	 * device is unused, ie before open() and after release().
 	 *
 	 * This Runtime PM callback does not need to save or restore
 	 * any registers since user space is responsbile for hardware
 	 * register reinitialization after open().
 	 */
 	return 0;
 }

 static const struct dev_pm_ops uio_pdrv_genirq_dev_pm_ops = {
 	.runtime_suspend = uio_pdrv_genirq_runtime_nop,
 	.runtime_resume = uio_pdrv_genirq_runtime_nop,
 };

 static struct platform_driver uio_pdrv_genirq = {
 	.probe = uio_pdrv_genirq_probe,
 	.remove = uio_pdrv_genirq_remove,
 	.driver = {
 		.name = DRIVER_NAME,
 		.owner = THIS_MODULE,
 		.pm = &uio_pdrv_genirq_dev_pm_ops,
 	},
 };

 static int __init uio_pdrv_genirq_init(void)
 {
 	return platform_driver_register(&uio_pdrv_genirq);
 }

 static void __exit uio_pdrv_genirq_exit(void)
 {
 	platform_driver_unregister(&uio_pdrv_genirq);
 }

 module_init(uio_pdrv_genirq_init);
 module_exit(uio_pdrv_genirq_exit);

 MODULE_AUTHOR("Magnus Damm");
 MODULE_DESCRIPTION("Userspace I/O platform driver with generic IRQ handling");
 MODULE_LICENSE("GPL v2");
 MODULE_ALIAS("platform:" DRIVER_NAME);
	/*
	* drivers/uio/uio_pdrv_genirq.c
	*
	* Userspace I/O platform driver with generic IRQ handling code.
	*
	* Copyright (C) 2008 Magnus Damm
	*
	* Based on uio_pdrv.c by Uwe Kleine-Koenig,
	* Copyright (C) 2008 by Digi International Inc.
	* All rights reserved.
	*
	* This program is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 as published by
	* the Free Software Foundation.
	*/

	#include <linux/platform_device.h>
	#include <linux/uio_driver.h>
	#include <linux/spinlock.h>
	#include <linux/bitops.h>
	#include <linux/interrupt.h>
	#include <linux/stringify.h>
	#include <linux/pm_runtime.h>
	#include <linux/slab.h>

	#define DRIVER_NAME "uio_pdrv_genirq"

	struct uio_pdrv_genirq_platdata {
	struct uio_info *uioinfo;
	spinlock_t lock;
	unsigned long flags;
	struct platform_device *pdev;
	};

	static int uio_pdrv_genirq_open(struct uio_info info, struct inode inode)
	{
	struct uio_pdrv_genirq_platdata *priv = info->priv;

	/* Wait until the Runtime PM code has woken up the device */
	pm_runtime_get_sync(&priv->pdev->dev);
	return 0;
	}

	static int uio_pdrv_genirq_release(struct uio_info info, struct inode inode)
	{
	struct uio_pdrv_genirq_platdata *priv = info->priv;

	/* Tell the Runtime PM code that the device has become idle */
	pm_runtime_put_sync(&priv->pdev->dev);
	return 0;
	}

	static irqreturn_t uio_pdrv_genirq_handler(int irq, struct uio_info *dev_info)
	{
	struct uio_pdrv_genirq_platdata *priv = dev_info->priv;

	/* Just disable the interrupt in the interrupt controller, and
	* remember the state so we can allow user space to enable it later.
	*/

	if (!test_and_set_bit(0, &priv->flags))
	disable_irq_nosync(irq);

	return IRQ_HANDLED;
	}

	static int uio_pdrv_genirq_irqcontrol(struct uio_info *dev_info, s32 irq_on)
	{
	struct uio_pdrv_genirq_platdata *priv = dev_info->priv;
	unsigned long flags;

	/* Allow user space to enable and disable the interrupt
	* in the interrupt controller, but keep track of the
	* state to prevent per-irq depth damage.
	*
	* Serialize this operation to support multiple tasks.
	*/

	spin_lock_irqsave(&priv->lock, flags);
	if (irq_on) {
	if (test_and_clear_bit(0, &priv->flags))
	enable_irq(dev_info->irq);
	} else {
	if (!test_and_set_bit(0, &priv->flags))
	disable_irq(dev_info->irq);
	}
	spin_unlock_irqrestore(&priv->lock, flags);

	return 0;
	}

	static int uio_pdrv_genirq_probe(struct platform_device *pdev)
	{
	struct uio_info *uioinfo = pdev->dev.platform_data;
	struct uio_pdrv_genirq_platdata *priv;
	struct uio_mem *uiomem;
	int ret = -EINVAL;
	int i;

	if (!uioinfo \|\| !uioinfo->name \|\| !uioinfo->version) {
	dev_err(&pdev->dev, "missing platform_data\n");
	goto bad0;
	}

	if (uioinfo->handler \|\| uioinfo->irqcontrol \|\|
	uioinfo->irq_flags & IRQF_SHARED) {
	dev_err(&pdev->dev, "interrupt configuration error\n");
	goto bad0;
	}

	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
	if (!priv) {
	ret = -ENOMEM;
	dev_err(&pdev->dev, "unable to kmalloc\n");
	goto bad0;
	}

	priv->uioinfo = uioinfo;
	spin_lock_init(&priv->lock);
	priv->flags = 0; /* interrupt is enabled to begin with */
	priv->pdev = pdev;

	uiomem = &uioinfo->mem[0];

	for (i = 0; i < pdev->num_resources; ++i) {
	struct resource *r = &pdev->resource[i];

	if (r->flags != IORESOURCE_MEM)
	continue;

	if (uiomem >= &uioinfo->mem[MAX_UIO_MAPS]) {
	dev_warn(&pdev->dev, "device has more than "
	__stringify(MAX_UIO_MAPS)
	" I/O memory resources.\n");
	break;
	}

	uiomem->memtype = UIO_MEM_PHYS;
	uiomem->addr = r->start;
	uiomem->size = r->end - r->start + 1;
	++uiomem;
	}

	while (uiomem < &uioinfo->mem[MAX_UIO_MAPS]) {
	uiomem->size = 0;
	++uiomem;
	}

	/* This driver requires no hardware specific kernel code to handle
	* interrupts. Instead, the interrupt handler simply disables the
	* interrupt in the interrupt controller. User space is responsible
	* for performing hardware specific acknowledge and re-enabling of
	* the interrupt in the interrupt controller.
	*
	* Interrupt sharing is not supported.
	*/

	uioinfo->irq_flags \|= IRQF_DISABLED;
	uioinfo->handler = uio_pdrv_genirq_handler;
	uioinfo->irqcontrol = uio_pdrv_genirq_irqcontrol;
	uioinfo->open = uio_pdrv_genirq_open;
	uioinfo->release = uio_pdrv_genirq_release;
	uioinfo->priv = priv;

	/* Enable Runtime PM for this device:
	* The device starts in suspended state to allow the hardware to be
	* turned off by default. The Runtime PM bus code should power on the
	* hardware and enable clocks at open().
	*/
	pm_runtime_enable(&pdev->dev);

	ret = uio_register_device(&pdev->dev, priv->uioinfo);
	if (ret) {
	dev_err(&pdev->dev, "unable to register uio device\n");
	goto bad1;
	}

	platform_set_drvdata(pdev, priv);
	return 0;
	bad1:
	kfree(priv);
	pm_runtime_disable(&pdev->dev);
	bad0:
	return ret;
	}

	static int uio_pdrv_genirq_remove(struct platform_device *pdev)
	{
	struct uio_pdrv_genirq_platdata *priv = platform_get_drvdata(pdev);

	uio_unregister_device(priv->uioinfo);
	pm_runtime_disable(&pdev->dev);
	kfree(priv);
	return 0;
	}

	static int uio_pdrv_genirq_runtime_nop(struct device *dev)
	{
	/* Runtime PM callback shared between ->runtime_suspend()
	* and ->runtime_resume(). Simply returns success.
	*
	* In this driver pm_runtime_get_sync() and pm_runtime_put_sync()
	* are used at open() and release() time. This allows the
	* Runtime PM code to turn off power to the device while the
	* device is unused, ie before open() and after release().
	*
	* This Runtime PM callback does not need to save or restore
	* any registers since user space is responsbile for hardware
	* register reinitialization after open().
	*/
	return 0;
	}

	static const struct dev_pm_ops uio_pdrv_genirq_dev_pm_ops = {
	.runtime_suspend = uio_pdrv_genirq_runtime_nop,
	.runtime_resume = uio_pdrv_genirq_runtime_nop,
	};

	static struct platform_driver uio_pdrv_genirq = {
	.probe = uio_pdrv_genirq_probe,
	.remove = uio_pdrv_genirq_remove,
	.driver = {
	.name = DRIVER_NAME,
	.owner = THIS_MODULE,
	.pm = &uio_pdrv_genirq_dev_pm_ops,
	},
	};

	static int __init uio_pdrv_genirq_init(void)
	{
	return platform_driver_register(&uio_pdrv_genirq);
	}

	static void __exit uio_pdrv_genirq_exit(void)
	{
	platform_driver_unregister(&uio_pdrv_genirq);
	}

	module_init(uio_pdrv_genirq_init);
	module_exit(uio_pdrv_genirq_exit);

	MODULE_AUTHOR("Magnus Damm");
	MODULE_DESCRIPTION("Userspace I/O platform driver with generic IRQ handling");
	MODULE_LICENSE("GPL v2");
	MODULE_ALIAS("platform:" DRIVER_NAME);