[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/module.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;
};

/* Bits in uio_pdrv_genirq_platdata.flags */
enum {
	UIO_IRQ_DISABLED = 0,
};

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.
	 */

	spin_lock(&priv->lock);
	if (!__test_and_set_bit(UIO_IRQ_DISABLED, &priv->flags))
		disable_irq_nosync(irq);
	spin_unlock(&priv->lock);

	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 and concurrency
	 * with irq handler on SMP systems.
	 */

	spin_lock_irqsave(&priv->lock, flags);
	if (irq_on) {
		if (__test_and_clear_bit(UIO_IRQ_DISABLED, &priv->flags))
			enable_irq(dev_info->irq);
	} else {
		if (!__test_and_set_bit(UIO_IRQ_DISABLED, &priv->flags))
			disable_irq_nosync(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 = dev_get_platdata(&pdev->dev);
	struct uio_pdrv_genirq_platdata *priv;
	struct uio_mem *uiomem;
	int ret = -EINVAL;
	int i;

	if (pdev->dev.of_node) {
		/* alloc uioinfo for one device */
		uioinfo = devm_kzalloc(&pdev->dev, sizeof(*uioinfo),
				       GFP_KERNEL);
		if (!uioinfo) {
			dev_err(&pdev->dev, "unable to kmalloc\n");
			return -ENOMEM;
		}
		uioinfo->name = devm_kasprintf(&pdev->dev, GFP_KERNEL, "%pOFn",
					       pdev->dev.of_node);
		uioinfo->version = "devicetree";
		/* Multiple IRQs are not supported */
	}

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

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

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

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

	if (!uioinfo->irq) {
		ret = platform_get_irq(pdev, 0);
		uioinfo->irq = ret;
		if (ret == -ENXIO && pdev->dev.of_node)
			uioinfo->irq = UIO_IRQ_NONE;
		else if (ret < 0) {
			dev_err(&pdev->dev, "failed to get IRQ\n");
			return ret;
		}
	}

	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->name = r->name;
		++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");
		pm_runtime_disable(&pdev->dev);
		return ret;
	}

	platform_set_drvdata(pdev, priv);
	return 0;
}

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;

	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 struct of_device_id uio_of_genirq_match[] = {
	{ /* This is filled with module_parm */ },
	{ /* Sentinel */ },
};
MODULE_DEVICE_TABLE(of, uio_of_genirq_match);
module_param_string(of_id, uio_of_genirq_match[0].compatible, 128, 0);
MODULE_PARM_DESC(of_id, "Openfirmware id of the device to be handled by uio");
#endif

static struct platform_driver uio_pdrv_genirq = {
	.probe = uio_pdrv_genirq_probe,
	.remove = uio_pdrv_genirq_remove,
	.driver = {
		.name = DRIVER_NAME,
		.pm = &uio_pdrv_genirq_dev_pm_ops,
		.of_match_table = of_match_ptr(uio_of_genirq_match),
	},
};

module_platform_driver(uio_pdrv_genirq);

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>
2949ead4	21	#include <linux/module.h>
c767db0a MD	22	#include <linux/interrupt.h>
c767db0a MD	23	#include <linux/stringify.h>
af76756e	24	#include <linux/pm_runtime.h>
5a0e3ad6	25	#include <linux/slab.h>
c767db0a	26
27760f86 HK	27	#include <linux/of.h>
	28	#include <linux/of_platform.h>
	29	#include <linux/of_address.h>
	30
c767db0a MD	31	#define DRIVER_NAME "uio_pdrv_genirq"
	32
	33	struct uio_pdrv_genirq_platdata {
	34	struct uio_info *uioinfo;
	35	spinlock_t lock;
	36	unsigned long flags;
af76756e	37	struct platform_device *pdev;
c767db0a MD	38	};
c767db0a MD	39
34cb2752 VD	40	/* Bits in uio_pdrv_genirq_platdata.flags */
	41	enum {
	42	UIO_IRQ_DISABLED = 0,
	43	};
	44
af76756e MD	45	static int uio_pdrv_genirq_open(struct uio_info info, struct inode inode)
	46	{
	47	struct uio_pdrv_genirq_platdata *priv = info->priv;
	48
	49	/* Wait until the Runtime PM code has woken up the device */
	50	pm_runtime_get_sync(&priv->pdev->dev);
	51	return 0;
	52	}
	53
	54	static int uio_pdrv_genirq_release(struct uio_info info, struct inode inode)
	55	{
	56	struct uio_pdrv_genirq_platdata *priv = info->priv;
	57
	58	/* Tell the Runtime PM code that the device has become idle */
	59	pm_runtime_put_sync(&priv->pdev->dev);
	60	return 0;
	61	}
	62
c767db0a MD	63	static irqreturn_t uio_pdrv_genirq_handler(int irq, struct uio_info *dev_info)
	64	{
	65	struct uio_pdrv_genirq_platdata *priv = dev_info->priv;
	66
	67	/* Just disable the interrupt in the interrupt controller, and
	68	* remember the state so we can allow user space to enable it later.
	69	*/
	70
34cb2752 VD	71	spin_lock(&priv->lock);
34cb2752 VD	72	if (!__test_and_set_bit(UIO_IRQ_DISABLED, &priv->flags))
c767db0a	73	disable_irq_nosync(irq);
34cb2752	74	spin_unlock(&priv->lock);
c767db0a MD	75
	76	return IRQ_HANDLED;
	77	}
	78
	79	static int uio_pdrv_genirq_irqcontrol(struct uio_info *dev_info, s32 irq_on)
	80	{
	81	struct uio_pdrv_genirq_platdata *priv = dev_info->priv;
	82	unsigned long flags;
	83
	84	/* Allow user space to enable and disable the interrupt
	85	* in the interrupt controller, but keep track of the
	86	* state to prevent per-irq depth damage.
	87	*
34cb2752 VD	88	* Serialize this operation to support multiple tasks and concurrency
34cb2752 VD	89	* with irq handler on SMP systems.
c767db0a MD	90	*/
	91
	92	spin_lock_irqsave(&priv->lock, flags);
	93	if (irq_on) {
34cb2752	94	if (__test_and_clear_bit(UIO_IRQ_DISABLED, &priv->flags))
c767db0a MD	95	enable_irq(dev_info->irq);
c767db0a MD	96	} else {
34cb2752 VD	97	if (!__test_and_set_bit(UIO_IRQ_DISABLED, &priv->flags))
34cb2752 VD	98	disable_irq_nosync(dev_info->irq);
c767db0a MD	99	}
	100	spin_unlock_irqrestore(&priv->lock, flags);
	101
	102	return 0;
	103	}
	104
	105	static int uio_pdrv_genirq_probe(struct platform_device *pdev)
	106	{
08cb2e21	107	struct uio_info *uioinfo = dev_get_platdata(&pdev->dev);
c767db0a MD	108	struct uio_pdrv_genirq_platdata *priv;
	109	struct uio_mem *uiomem;
	110	int ret = -EINVAL;
	111	int i;
	112
d5185c4e	113	if (pdev->dev.of_node) {
27760f86	114	/* alloc uioinfo for one device */
e6789cd3 MS	115	uioinfo = devm_kzalloc(&pdev->dev, sizeof(*uioinfo),
e6789cd3 MS	116	GFP_KERNEL);
27760f86	117	if (!uioinfo) {
27760f86	118	dev_err(&pdev->dev, "unable to kmalloc\n");
e6789cd3	119	return -ENOMEM;
27760f86	120	}
52e2dc2c RH	121	uioinfo->name = devm_kasprintf(&pdev->dev, GFP_KERNEL, "%pOFn",
52e2dc2c RH	122	pdev->dev.of_node);
27760f86	123	uioinfo->version = "devicetree";
27760f86	124	/* Multiple IRQs are not supported */
27760f86 HK	125	}
27760f86 HK	126
c767db0a MD	127	if (!uioinfo \|\| !uioinfo->name \|\| !uioinfo->version) {
c767db0a MD	128	dev_err(&pdev->dev, "missing platform_data\n");
e6789cd3	129	return ret;
c767db0a MD	130	}
c767db0a MD	131
e543ae89 MF	132	if (uioinfo->handler \|\| uioinfo->irqcontrol \|\|
e543ae89 MF	133	uioinfo->irq_flags & IRQF_SHARED) {
c767db0a	134	dev_err(&pdev->dev, "interrupt configuration error\n");
e6789cd3	135	return ret;
c767db0a MD	136	}
c767db0a MD	137
e6789cd3	138	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
c767db0a	139	if (!priv) {
c767db0a	140	dev_err(&pdev->dev, "unable to kmalloc\n");
e6789cd3	141	return -ENOMEM;
c767db0a MD	142	}
	143
	144	priv->uioinfo = uioinfo;
	145	spin_lock_init(&priv->lock);
	146	priv->flags = 0; /* interrupt is enabled to begin with */
af76756e	147	priv->pdev = pdev;
c767db0a	148
94ca629e BS	149	if (!uioinfo->irq) {
94ca629e BS	150	ret = platform_get_irq(pdev, 0);
e3a3c3a2 PM	151	uioinfo->irq = ret;
	152	if (ret == -ENXIO && pdev->dev.of_node)
	153	uioinfo->irq = UIO_IRQ_NONE;
	154	else if (ret < 0) {
94ca629e	155	dev_err(&pdev->dev, "failed to get IRQ\n");
e6789cd3	156	return ret;
94ca629e	157	}
94ca629e	158	}
e3a3c3a2	159
c767db0a MD	160	uiomem = &uioinfo->mem[0];
	161
	162	for (i = 0; i < pdev->num_resources; ++i) {
	163	struct resource *r = &pdev->resource[i];
	164
	165	if (r->flags != IORESOURCE_MEM)
	166	continue;
	167
	168	if (uiomem >= &uioinfo->mem[MAX_UIO_MAPS]) {
	169	dev_warn(&pdev->dev, "device has more than "
	170	__stringify(MAX_UIO_MAPS)
	171	" I/O memory resources.\n");
	172	break;
	173	}
	174
	175	uiomem->memtype = UIO_MEM_PHYS;
	176	uiomem->addr = r->start;
28f65c11	177	uiomem->size = resource_size(r);
ecd43c0d	178	uiomem->name = r->name;
c767db0a MD	179	++uiomem;
	180	}
	181
	182	while (uiomem < &uioinfo->mem[MAX_UIO_MAPS]) {
	183	uiomem->size = 0;
	184	++uiomem;
	185	}
	186
	187	/* This driver requires no hardware specific kernel code to handle
	188	* interrupts. Instead, the interrupt handler simply disables the
	189	* interrupt in the interrupt controller. User space is responsible
	190	* for performing hardware specific acknowledge and re-enabling of
	191	* the interrupt in the interrupt controller.
	192	*
	193	* Interrupt sharing is not supported.
	194	*/
	195
c767db0a MD	196	uioinfo->handler = uio_pdrv_genirq_handler;
c767db0a MD	197	uioinfo->irqcontrol = uio_pdrv_genirq_irqcontrol;
af76756e MD	198	uioinfo->open = uio_pdrv_genirq_open;
af76756e MD	199	uioinfo->release = uio_pdrv_genirq_release;
c767db0a MD	200	uioinfo->priv = priv;
c767db0a MD	201
af76756e MD	202	/* Enable Runtime PM for this device:
	203	* The device starts in suspended state to allow the hardware to be
	204	* turned off by default. The Runtime PM bus code should power on the
	205	* hardware and enable clocks at open().
	206	*/
	207	pm_runtime_enable(&pdev->dev);
	208
c767db0a MD	209	ret = uio_register_device(&pdev->dev, priv->uioinfo);
	210	if (ret) {
	211	dev_err(&pdev->dev, "unable to register uio device\n");
e6789cd3 MS	212	pm_runtime_disable(&pdev->dev);
e6789cd3 MS	213	return ret;
c767db0a MD	214	}
	215
	216	platform_set_drvdata(pdev, priv);
	217	return 0;
c767db0a MD	218	}
	219
	220	static int uio_pdrv_genirq_remove(struct platform_device *pdev)
	221	{
	222	struct uio_pdrv_genirq_platdata *priv = platform_get_drvdata(pdev);
	223
	224	uio_unregister_device(priv->uioinfo);
af76756e	225	pm_runtime_disable(&pdev->dev);
47296b19 JZ	226
	227	priv->uioinfo->handler = NULL;
	228	priv->uioinfo->irqcontrol = NULL;
	229
c767db0a MD	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
05c3e0bb PM	256	static struct of_device_id uio_of_genirq_match[] = {
	257	{ /* This is filled with module_parm */ },
	258	{ /* Sentinel */ },
27760f86 HK	259	};
27760f86 HK	260	MODULE_DEVICE_TABLE(of, uio_of_genirq_match);
05c3e0bb PM	261	module_param_string(of_id, uio_of_genirq_match[0].compatible, 128, 0);
05c3e0bb PM	262	MODULE_PARM_DESC(of_id, "Openfirmware id of the device to be handled by uio");
27760f86 HK	263	#endif
27760f86 HK	264
c767db0a MD	265	static struct platform_driver uio_pdrv_genirq = {
	266	.probe = uio_pdrv_genirq_probe,
	267	.remove = uio_pdrv_genirq_remove,
	268	.driver = {
	269	.name = DRIVER_NAME,
af76756e	270	.pm = &uio_pdrv_genirq_dev_pm_ops,
cee4fbd6	271	.of_match_table = of_match_ptr(uio_of_genirq_match),
c767db0a MD	272	},
	273	};
	274
11e3123d	275	module_platform_driver(uio_pdrv_genirq);
c767db0a MD	276
	277	MODULE_AUTHOR("Magnus Damm");
	278	MODULE_DESCRIPTION("Userspace I/O platform driver with generic IRQ handling");
	279	MODULE_LICENSE("GPL v2");
	280	MODULE_ALIAS("platform:" DRIVER_NAME);