[linux-2.6-block.git] / drivers / uio / uio_pdrv_genirq.c

/*
 * 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>

#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);
Commit	Line	Data
c767db0a MD	1	/*
	2	* drivers/uio/uio_pdrv_genirq.c
	3	*
	4	* Userspace I/O platform driver with generic IRQ handling code.
	5	*
	6	* Copyright (C) 2008 Magnus Damm
	7	*
	8	* Based on uio_pdrv.c by Uwe Kleine-Koenig,
	9	* Copyright (C) 2008 by Digi International Inc.
	10	* All rights reserved.
	11	*
	12	* This program is free software; you can redistribute it and/or modify it
	13	* under the terms of the GNU General Public License version 2 as published by
	14	* the Free Software Foundation.
	15	*/
	16
	17	#include <linux/platform_device.h>
	18	#include <linux/uio_driver.h>
	19	#include <linux/spinlock.h>
	20	#include <linux/bitops.h>
	21	#include <linux/interrupt.h>
	22	#include <linux/stringify.h>
af76756e	23	#include <linux/pm_runtime.h>
c767db0a MD	24
	25	#define DRIVER_NAME "uio_pdrv_genirq"
	26
	27	struct uio_pdrv_genirq_platdata {
	28	struct uio_info *uioinfo;
	29	spinlock_t lock;
	30	unsigned long flags;
af76756e	31	struct platform_device *pdev;
c767db0a MD	32	};
c767db0a MD	33
af76756e MD	34	static int uio_pdrv_genirq_open(struct uio_info info, struct inode inode)
	35	{
	36	struct uio_pdrv_genirq_platdata *priv = info->priv;
	37
	38	/* Wait until the Runtime PM code has woken up the device */
	39	pm_runtime_get_sync(&priv->pdev->dev);
	40	return 0;
	41	}
	42
	43	static int uio_pdrv_genirq_release(struct uio_info info, struct inode inode)
	44	{
	45	struct uio_pdrv_genirq_platdata *priv = info->priv;
	46
	47	/* Tell the Runtime PM code that the device has become idle */
	48	pm_runtime_put_sync(&priv->pdev->dev);
	49	return 0;
	50	}
	51
c767db0a MD	52	static irqreturn_t uio_pdrv_genirq_handler(int irq, struct uio_info *dev_info)
	53	{
	54	struct uio_pdrv_genirq_platdata *priv = dev_info->priv;
	55
	56	/* Just disable the interrupt in the interrupt controller, and
	57	* remember the state so we can allow user space to enable it later.
	58	*/
	59
	60	if (!test_and_set_bit(0, &priv->flags))
	61	disable_irq_nosync(irq);
	62
	63	return IRQ_HANDLED;
	64	}
	65
	66	static int uio_pdrv_genirq_irqcontrol(struct uio_info *dev_info, s32 irq_on)
	67	{
	68	struct uio_pdrv_genirq_platdata *priv = dev_info->priv;
	69	unsigned long flags;
	70
	71	/* Allow user space to enable and disable the interrupt
	72	* in the interrupt controller, but keep track of the
	73	* state to prevent per-irq depth damage.
	74	*
	75	* Serialize this operation to support multiple tasks.
	76	*/
	77
	78	spin_lock_irqsave(&priv->lock, flags);
	79	if (irq_on) {
	80	if (test_and_clear_bit(0, &priv->flags))
	81	enable_irq(dev_info->irq);
	82	} else {
	83	if (!test_and_set_bit(0, &priv->flags))
	84	disable_irq(dev_info->irq);
	85	}
	86	spin_unlock_irqrestore(&priv->lock, flags);
	87
	88	return 0;
	89	}
	90
	91	static int uio_pdrv_genirq_probe(struct platform_device *pdev)
	92	{
	93	struct uio_info *uioinfo = pdev->dev.platform_data;
	94	struct uio_pdrv_genirq_platdata *priv;
	95	struct uio_mem *uiomem;
	96	int ret = -EINVAL;
	97	int i;
	98
	99	if (!uioinfo \|\| !uioinfo->name \|\| !uioinfo->version) {
	100	dev_err(&pdev->dev, "missing platform_data\n");
	101	goto bad0;
	102	}
	103
e543ae89 MF	104	if (uioinfo->handler \|\| uioinfo->irqcontrol \|\|
e543ae89 MF	105	uioinfo->irq_flags & IRQF_SHARED) {
c767db0a MD	106	dev_err(&pdev->dev, "interrupt configuration error\n");
	107	goto bad0;
	108	}
	109
	110	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
	111	if (!priv) {
	112	ret = -ENOMEM;
	113	dev_err(&pdev->dev, "unable to kmalloc\n");
	114	goto bad0;
	115	}
	116
	117	priv->uioinfo = uioinfo;
	118	spin_lock_init(&priv->lock);
	119	priv->flags = 0; /* interrupt is enabled to begin with */
af76756e	120	priv->pdev = pdev;
c767db0a MD	121
	122	uiomem = &uioinfo->mem[0];
	123
	124	for (i = 0; i < pdev->num_resources; ++i) {
	125	struct resource *r = &pdev->resource[i];
	126
	127	if (r->flags != IORESOURCE_MEM)
	128	continue;
	129
	130	if (uiomem >= &uioinfo->mem[MAX_UIO_MAPS]) {
	131	dev_warn(&pdev->dev, "device has more than "
	132	__stringify(MAX_UIO_MAPS)
	133	" I/O memory resources.\n");
	134	break;
	135	}
	136
	137	uiomem->memtype = UIO_MEM_PHYS;
	138	uiomem->addr = r->start;
	139	uiomem->size = r->end - r->start + 1;
	140	++uiomem;
	141	}
	142
	143	while (uiomem < &uioinfo->mem[MAX_UIO_MAPS]) {
	144	uiomem->size = 0;
	145	++uiomem;
	146	}
	147
	148	/* This driver requires no hardware specific kernel code to handle
	149	* interrupts. Instead, the interrupt handler simply disables the
	150	* interrupt in the interrupt controller. User space is responsible
	151	* for performing hardware specific acknowledge and re-enabling of
	152	* the interrupt in the interrupt controller.
	153	*
	154	* Interrupt sharing is not supported.
	155	*/
	156
e543ae89	157	uioinfo->irq_flags \|= IRQF_DISABLED;
c767db0a MD	158	uioinfo->handler = uio_pdrv_genirq_handler;
c767db0a MD	159	uioinfo->irqcontrol = uio_pdrv_genirq_irqcontrol;
af76756e MD	160	uioinfo->open = uio_pdrv_genirq_open;
af76756e MD	161	uioinfo->release = uio_pdrv_genirq_release;
c767db0a MD	162	uioinfo->priv = priv;
c767db0a MD	163
af76756e MD	164	/* Enable Runtime PM for this device:
	165	* The device starts in suspended state to allow the hardware to be
	166	* turned off by default. The Runtime PM bus code should power on the
	167	* hardware and enable clocks at open().
	168	*/
	169	pm_runtime_enable(&pdev->dev);
	170
c767db0a MD	171	ret = uio_register_device(&pdev->dev, priv->uioinfo);
	172	if (ret) {
	173	dev_err(&pdev->dev, "unable to register uio device\n");
	174	goto bad1;
	175	}
	176
	177	platform_set_drvdata(pdev, priv);
	178	return 0;
	179	bad1:
	180	kfree(priv);
68fb2e49	181	pm_runtime_disable(&pdev->dev);
c767db0a MD	182	bad0:
	183	return ret;
	184	}
	185
	186	static int uio_pdrv_genirq_remove(struct platform_device *pdev)
	187	{
	188	struct uio_pdrv_genirq_platdata *priv = platform_get_drvdata(pdev);
	189
	190	uio_unregister_device(priv->uioinfo);
af76756e	191	pm_runtime_disable(&pdev->dev);
c767db0a MD	192	kfree(priv);
	193	return 0;
	194	}
	195
af76756e MD	196	static int uio_pdrv_genirq_runtime_nop(struct device *dev)
	197	{
	198	/* Runtime PM callback shared between ->runtime_suspend()
	199	* and ->runtime_resume(). Simply returns success.
	200	*
	201	* In this driver pm_runtime_get_sync() and pm_runtime_put_sync()
	202	* are used at open() and release() time. This allows the
	203	* Runtime PM code to turn off power to the device while the
	204	* device is unused, ie before open() and after release().
	205	*
	206	* This Runtime PM callback does not need to save or restore
	207	* any registers since user space is responsbile for hardware
	208	* register reinitialization after open().
	209	*/
	210	return 0;
	211	}
	212
47145210	213	static const struct dev_pm_ops uio_pdrv_genirq_dev_pm_ops = {
af76756e MD	214	.runtime_suspend = uio_pdrv_genirq_runtime_nop,
	215	.runtime_resume = uio_pdrv_genirq_runtime_nop,
	216	};
	217
c767db0a MD	218	static struct platform_driver uio_pdrv_genirq = {
	219	.probe = uio_pdrv_genirq_probe,
	220	.remove = uio_pdrv_genirq_remove,
	221	.driver = {
	222	.name = DRIVER_NAME,
	223	.owner = THIS_MODULE,
af76756e	224	.pm = &uio_pdrv_genirq_dev_pm_ops,
c767db0a MD	225	},
	226	};
	227
	228	static int __init uio_pdrv_genirq_init(void)
	229	{
	230	return platform_driver_register(&uio_pdrv_genirq);
	231	}
	232
	233	static void __exit uio_pdrv_genirq_exit(void)
	234	{
	235	platform_driver_unregister(&uio_pdrv_genirq);
	236	}
	237
	238	module_init(uio_pdrv_genirq_init);
	239	module_exit(uio_pdrv_genirq_exit);
	240
	241	MODULE_AUTHOR("Magnus Damm");
	242	MODULE_DESCRIPTION("Userspace I/O platform driver with generic IRQ handling");
	243	MODULE_LICENSE("GPL v2");
	244	MODULE_ALIAS("platform:" DRIVER_NAME);