[deliverable/linux.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>
#include <linux/slab.h>

#include <linux/of.h>
#include <linux/of_platform.h>
#include <linux/of_address.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) {
		int irq;

		/* alloc uioinfo for one device */
		uioinfo = kzalloc(sizeof(*uioinfo), GFP_KERNEL);
		if (!uioinfo) {
			ret = -ENOMEM;
			dev_err(&pdev->dev, "unable to kmalloc\n");
			goto bad2;
		}
		uioinfo->name = pdev->dev.of_node->name;
		uioinfo->version = "devicetree";

		/* Multiple IRQs are not supported */
		irq = platform_get_irq(pdev, 0);
		if (irq == -ENXIO)
			uioinfo->irq = UIO_IRQ_NONE;
		else
			uioinfo->irq = irq;
	}

	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 = resource_size(r);
		++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->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:
	/* kfree uioinfo for OF */
	if (pdev->dev.of_node)
		kfree(uioinfo);
 bad2:
	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);

	priv->uioinfo->handler = NULL;
	priv->uioinfo->irqcontrol = NULL;

	/* kfree uioinfo for OF */
	if (pdev->dev.of_node)
		kfree(priv->uioinfo);

	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,
};

#ifdef CONFIG_OF
static const struct of_device_id uio_of_genirq_match[] = {
	{ /* empty for now */ },
};
MODULE_DEVICE_TABLE(of, uio_of_genirq_match);
#else
# define uio_of_genirq_match NULL
#endif

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,
		.of_match_table = uio_of_genirq_match,
	},
};

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>
5a0e3ad6	24	#include <linux/slab.h>
c767db0a	25
27760f86 HK	26	#include <linux/of.h>
	27	#include <linux/of_platform.h>
	28	#include <linux/of_address.h>
	29
c767db0a MD	30	#define DRIVER_NAME "uio_pdrv_genirq"
	31
	32	struct uio_pdrv_genirq_platdata {
	33	struct uio_info *uioinfo;
	34	spinlock_t lock;
	35	unsigned long flags;
af76756e	36	struct platform_device *pdev;
c767db0a MD	37	};
c767db0a MD	38
af76756e MD	39	static int uio_pdrv_genirq_open(struct uio_info info, struct inode inode)
	40	{
	41	struct uio_pdrv_genirq_platdata *priv = info->priv;
	42
	43	/* Wait until the Runtime PM code has woken up the device */
	44	pm_runtime_get_sync(&priv->pdev->dev);
	45	return 0;
	46	}
	47
	48	static int uio_pdrv_genirq_release(struct uio_info info, struct inode inode)
	49	{
	50	struct uio_pdrv_genirq_platdata *priv = info->priv;
	51
	52	/* Tell the Runtime PM code that the device has become idle */
	53	pm_runtime_put_sync(&priv->pdev->dev);
	54	return 0;
	55	}
	56
c767db0a MD	57	static irqreturn_t uio_pdrv_genirq_handler(int irq, struct uio_info *dev_info)
	58	{
	59	struct uio_pdrv_genirq_platdata *priv = dev_info->priv;
	60
	61	/* Just disable the interrupt in the interrupt controller, and
	62	* remember the state so we can allow user space to enable it later.
	63	*/
	64
	65	if (!test_and_set_bit(0, &priv->flags))
	66	disable_irq_nosync(irq);
	67
	68	return IRQ_HANDLED;
	69	}
	70
	71	static int uio_pdrv_genirq_irqcontrol(struct uio_info *dev_info, s32 irq_on)
	72	{
	73	struct uio_pdrv_genirq_platdata *priv = dev_info->priv;
	74	unsigned long flags;
	75
	76	/* Allow user space to enable and disable the interrupt
	77	* in the interrupt controller, but keep track of the
	78	* state to prevent per-irq depth damage.
	79	*
	80	* Serialize this operation to support multiple tasks.
	81	*/
	82
	83	spin_lock_irqsave(&priv->lock, flags);
	84	if (irq_on) {
	85	if (test_and_clear_bit(0, &priv->flags))
	86	enable_irq(dev_info->irq);
	87	} else {
	88	if (!test_and_set_bit(0, &priv->flags))
	89	disable_irq(dev_info->irq);
	90	}
	91	spin_unlock_irqrestore(&priv->lock, flags);
	92
	93	return 0;
	94	}
	95
	96	static int uio_pdrv_genirq_probe(struct platform_device *pdev)
	97	{
	98	struct uio_info *uioinfo = pdev->dev.platform_data;
	99	struct uio_pdrv_genirq_platdata *priv;
	100	struct uio_mem *uiomem;
	101	int ret = -EINVAL;
	102	int i;
	103
27760f86 HK	104	if (!uioinfo) {
	105	int irq;
	106
	107	/* alloc uioinfo for one device */
	108	uioinfo = kzalloc(sizeof(*uioinfo), GFP_KERNEL);
	109	if (!uioinfo) {
	110	ret = -ENOMEM;
	111	dev_err(&pdev->dev, "unable to kmalloc\n");
	112	goto bad2;
	113	}
	114	uioinfo->name = pdev->dev.of_node->name;
	115	uioinfo->version = "devicetree";
	116
	117	/* Multiple IRQs are not supported */
	118	irq = platform_get_irq(pdev, 0);
	119	if (irq == -ENXIO)
	120	uioinfo->irq = UIO_IRQ_NONE;
	121	else
	122	uioinfo->irq = irq;
	123	}
	124
c767db0a MD	125	if (!uioinfo \|\| !uioinfo->name \|\| !uioinfo->version) {
	126	dev_err(&pdev->dev, "missing platform_data\n");
	127	goto bad0;
	128	}
	129
e543ae89 MF	130	if (uioinfo->handler \|\| uioinfo->irqcontrol \|\|
e543ae89 MF	131	uioinfo->irq_flags & IRQF_SHARED) {
c767db0a MD	132	dev_err(&pdev->dev, "interrupt configuration error\n");
	133	goto bad0;
	134	}
	135
	136	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
	137	if (!priv) {
	138	ret = -ENOMEM;
	139	dev_err(&pdev->dev, "unable to kmalloc\n");
	140	goto bad0;
	141	}
	142
	143	priv->uioinfo = uioinfo;
	144	spin_lock_init(&priv->lock);
	145	priv->flags = 0; /* interrupt is enabled to begin with */
af76756e	146	priv->pdev = pdev;
c767db0a MD	147
	148	uiomem = &uioinfo->mem[0];
	149
	150	for (i = 0; i < pdev->num_resources; ++i) {
	151	struct resource *r = &pdev->resource[i];
	152
	153	if (r->flags != IORESOURCE_MEM)
	154	continue;
	155
	156	if (uiomem >= &uioinfo->mem[MAX_UIO_MAPS]) {
	157	dev_warn(&pdev->dev, "device has more than "
	158	__stringify(MAX_UIO_MAPS)
	159	" I/O memory resources.\n");
	160	break;
	161	}
	162
	163	uiomem->memtype = UIO_MEM_PHYS;
	164	uiomem->addr = r->start;
28f65c11	165	uiomem->size = resource_size(r);
c767db0a MD	166	++uiomem;
	167	}
	168
	169	while (uiomem < &uioinfo->mem[MAX_UIO_MAPS]) {
	170	uiomem->size = 0;
	171	++uiomem;
	172	}
	173
	174	/* This driver requires no hardware specific kernel code to handle
	175	* interrupts. Instead, the interrupt handler simply disables the
	176	* interrupt in the interrupt controller. User space is responsible
	177	* for performing hardware specific acknowledge and re-enabling of
	178	* the interrupt in the interrupt controller.
	179	*
	180	* Interrupt sharing is not supported.
	181	*/
	182
c767db0a MD	183	uioinfo->handler = uio_pdrv_genirq_handler;
c767db0a MD	184	uioinfo->irqcontrol = uio_pdrv_genirq_irqcontrol;
af76756e MD	185	uioinfo->open = uio_pdrv_genirq_open;
af76756e MD	186	uioinfo->release = uio_pdrv_genirq_release;
c767db0a MD	187	uioinfo->priv = priv;
c767db0a MD	188
af76756e MD	189	/* Enable Runtime PM for this device:
	190	* The device starts in suspended state to allow the hardware to be
	191	* turned off by default. The Runtime PM bus code should power on the
	192	* hardware and enable clocks at open().
	193	*/
	194	pm_runtime_enable(&pdev->dev);
	195
c767db0a MD	196	ret = uio_register_device(&pdev->dev, priv->uioinfo);
	197	if (ret) {
	198	dev_err(&pdev->dev, "unable to register uio device\n");
	199	goto bad1;
	200	}
	201
	202	platform_set_drvdata(pdev, priv);
	203	return 0;
	204	bad1:
	205	kfree(priv);
68fb2e49	206	pm_runtime_disable(&pdev->dev);
c767db0a	207	bad0:
27760f86 HK	208	/* kfree uioinfo for OF */
	209	if (pdev->dev.of_node)
	210	kfree(uioinfo);
	211	bad2:
c767db0a MD	212	return ret;
	213	}
	214
	215	static int uio_pdrv_genirq_remove(struct platform_device *pdev)
	216	{
	217	struct uio_pdrv_genirq_platdata *priv = platform_get_drvdata(pdev);
	218
	219	uio_unregister_device(priv->uioinfo);
af76756e	220	pm_runtime_disable(&pdev->dev);
47296b19 JZ	221
	222	priv->uioinfo->handler = NULL;
	223	priv->uioinfo->irqcontrol = NULL;
	224
27760f86 HK	225	/* kfree uioinfo for OF */
	226	if (pdev->dev.of_node)
	227	kfree(priv->uioinfo);
	228
c767db0a MD	229	kfree(priv);
	230	return 0;
	231	}
	232
af76756e MD	233	static int uio_pdrv_genirq_runtime_nop(struct device *dev)
	234	{
	235	/* Runtime PM callback shared between ->runtime_suspend()
	236	* and ->runtime_resume(). Simply returns success.
	237	*
	238	* In this driver pm_runtime_get_sync() and pm_runtime_put_sync()
	239	* are used at open() and release() time. This allows the
	240	* Runtime PM code to turn off power to the device while the
	241	* device is unused, ie before open() and after release().
	242	*
	243	* This Runtime PM callback does not need to save or restore
	244	* any registers since user space is responsbile for hardware
	245	* register reinitialization after open().
	246	*/
	247	return 0;
	248	}
	249
47145210	250	static const struct dev_pm_ops uio_pdrv_genirq_dev_pm_ops = {
af76756e MD	251	.runtime_suspend = uio_pdrv_genirq_runtime_nop,
	252	.runtime_resume = uio_pdrv_genirq_runtime_nop,
	253	};
	254
27760f86	255	#ifdef CONFIG_OF
9245acd2	256	static const struct of_device_id uio_of_genirq_match[] = {
27760f86 HK	257	{ /* empty for now */ },
	258	};
	259	MODULE_DEVICE_TABLE(of, uio_of_genirq_match);
	260	#else
	261	# define uio_of_genirq_match NULL
	262	#endif
	263
c767db0a MD	264	static struct platform_driver uio_pdrv_genirq = {
	265	.probe = uio_pdrv_genirq_probe,
	266	.remove = uio_pdrv_genirq_remove,
	267	.driver = {
	268	.name = DRIVER_NAME,
	269	.owner = THIS_MODULE,
af76756e	270	.pm = &uio_pdrv_genirq_dev_pm_ops,
27760f86	271	.of_match_table = uio_of_genirq_match,
c767db0a MD	272	},
	273	};
	274
	275	static int __init uio_pdrv_genirq_init(void)
	276	{
	277	return platform_driver_register(&uio_pdrv_genirq);
	278	}
	279
	280	static void __exit uio_pdrv_genirq_exit(void)
	281	{
	282	platform_driver_unregister(&uio_pdrv_genirq);
	283	}
	284
	285	module_init(uio_pdrv_genirq_init);
	286	module_exit(uio_pdrv_genirq_exit);
	287
	288	MODULE_AUTHOR("Magnus Damm");
	289	MODULE_DESCRIPTION("Userspace I/O platform driver with generic IRQ handling");
	290	MODULE_LICENSE("GPL v2");
	291	MODULE_ALIAS("platform:" DRIVER_NAME);