[mirror_ubuntu-jammy-kernel.git] / drivers / uio / uio_dmem_genirq.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * drivers/uio/uio_dmem_genirq.c
 *
 * Userspace I/O platform driver with generic IRQ handling code.
 *
 * Copyright (C) 2012 Damian Hobson-Garcia
 *
 * Based on uio_pdrv_genirq.c by Magnus Damm
 */

#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/platform_data/uio_dmem_genirq.h>
#include <linux/stringify.h>
#include <linux/pm_runtime.h>
#include <linux/dma-mapping.h>
#include <linux/slab.h>
#include <linux/irq.h>

#include <linux/of.h>
#include <linux/of_platform.h>
#include <linux/of_address.h>

#define DRIVER_NAME "uio_dmem_genirq"
#define DMEM_MAP_ERROR (~0)

struct uio_dmem_genirq_platdata {
	struct uio_info *uioinfo;
	spinlock_t lock;
	unsigned long flags;
	struct platform_device *pdev;
	unsigned int dmem_region_start;
	unsigned int num_dmem_regions;
	void *dmem_region_vaddr[MAX_UIO_MAPS];
	struct mutex alloc_lock;
	unsigned int refcnt;
};

static int uio_dmem_genirq_open(struct uio_info *info, struct inode *inode)
{
	struct uio_dmem_genirq_platdata *priv = info->priv;
	struct uio_mem *uiomem;
	int dmem_region = priv->dmem_region_start;

	uiomem = &priv->uioinfo->mem[priv->dmem_region_start];

	mutex_lock(&priv->alloc_lock);
	while (!priv->refcnt && uiomem < &priv->uioinfo->mem[MAX_UIO_MAPS]) {
		void *addr;
		if (!uiomem->size)
			break;

		addr = dma_alloc_coherent(&priv->pdev->dev, uiomem->size,
				(dma_addr_t *)&uiomem->addr, GFP_KERNEL);
		if (!addr) {
			uiomem->addr = DMEM_MAP_ERROR;
		}
		priv->dmem_region_vaddr[dmem_region++] = addr;
		++uiomem;
	}
	priv->refcnt++;

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

static int uio_dmem_genirq_release(struct uio_info *info, struct inode *inode)
{
	struct uio_dmem_genirq_platdata *priv = info->priv;
	struct uio_mem *uiomem;
	int dmem_region = priv->dmem_region_start;

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

	uiomem = &priv->uioinfo->mem[priv->dmem_region_start];

	mutex_lock(&priv->alloc_lock);

	priv->refcnt--;
	while (!priv->refcnt && uiomem < &priv->uioinfo->mem[MAX_UIO_MAPS]) {
		if (!uiomem->size)
			break;
		if (priv->dmem_region_vaddr[dmem_region]) {
			dma_free_coherent(&priv->pdev->dev, uiomem->size,
					priv->dmem_region_vaddr[dmem_region],
					uiomem->addr);
		}
		uiomem->addr = DMEM_MAP_ERROR;
		++dmem_region;
		++uiomem;
	}

	mutex_unlock(&priv->alloc_lock);
	return 0;
}

static irqreturn_t uio_dmem_genirq_handler(int irq, struct uio_info *dev_info)
{
	struct uio_dmem_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_dmem_genirq_irqcontrol(struct uio_info *dev_info, s32 irq_on)
{
	struct uio_dmem_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);
		spin_unlock_irqrestore(&priv->lock, flags);
	} else {
		if (!test_and_set_bit(0, &priv->flags)) {
			spin_unlock_irqrestore(&priv->lock, flags);
			disable_irq(dev_info->irq);
		}
	}

	return 0;
}

static void uio_dmem_genirq_pm_disable(void *data)
{
	struct device *dev = data;

	pm_runtime_disable(dev);
}

static int uio_dmem_genirq_probe(struct platform_device *pdev)
{
	struct uio_dmem_genirq_pdata *pdata = dev_get_platdata(&pdev->dev);
	struct uio_info *uioinfo = &pdata->uioinfo;
	struct uio_dmem_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";
	}

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

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

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

	dma_set_coherent_mask(&pdev->dev, DMA_BIT_MASK(32));

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

	if (!uioinfo->irq) {
		/* Multiple IRQs are not supported */
		ret = platform_get_irq(pdev, 0);
		if (ret == -ENXIO && pdev->dev.of_node)
			ret = UIO_IRQ_NONE;
		else if (ret < 0)
			return ret;
		uioinfo->irq = ret;
	}

	if (uioinfo->irq) {
		struct irq_data *irq_data = irq_get_irq_data(uioinfo->irq);

		/*
		 * If a level interrupt, dont do lazy disable. Otherwise the
		 * irq will fire again since clearing of the actual cause, on
		 * device level, is done in userspace
		 * irqd_is_level_type() isn't used since isn't valid until
		 * irq is configured.
		 */
		if (irq_data &&
		    irqd_get_trigger_type(irq_data) & IRQ_TYPE_LEVEL_MASK) {
			dev_dbg(&pdev->dev, "disable lazy unmask\n");
			irq_set_status_flags(uioinfo->irq, IRQ_DISABLE_UNLAZY);
		}
	}

	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;
	}

	priv->dmem_region_start = uiomem - &uioinfo->mem[0];
	priv->num_dmem_regions = pdata->num_dynamic_regions;

	for (i = 0; i < pdata->num_dynamic_regions; ++i) {
		if (uiomem >= &uioinfo->mem[MAX_UIO_MAPS]) {
			dev_warn(&pdev->dev, "device has more than "
					__stringify(MAX_UIO_MAPS)
					" dynamic and fixed memory regions.\n");
			break;
		}
		uiomem->memtype = UIO_MEM_PHYS;
		uiomem->addr = DMEM_MAP_ERROR;
		uiomem->size = pdata->dynamic_region_sizes[i];
		++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_dmem_genirq_handler;
	uioinfo->irqcontrol = uio_dmem_genirq_irqcontrol;
	uioinfo->open = uio_dmem_genirq_open;
	uioinfo->release = uio_dmem_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 = devm_add_action_or_reset(&pdev->dev, uio_dmem_genirq_pm_disable, &pdev->dev);
	if (ret)
		return ret;

	return devm_uio_register_device(&pdev->dev, priv->uioinfo);
}

static int uio_dmem_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_dmem_genirq_dev_pm_ops = {
	.runtime_suspend = uio_dmem_genirq_runtime_nop,
	.runtime_resume = uio_dmem_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);
#endif

static struct platform_driver uio_dmem_genirq = {
	.probe = uio_dmem_genirq_probe,
	.driver = {
		.name = DRIVER_NAME,
		.pm = &uio_dmem_genirq_dev_pm_ops,
		.of_match_table = of_match_ptr(uio_of_genirq_match),
	},
};

module_platform_driver(uio_dmem_genirq);

MODULE_AUTHOR("Damian Hobson-Garcia");
MODULE_DESCRIPTION("Userspace I/O platform driver with dynamic memory.");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:" DRIVER_NAME);
Commit	Line	Data
d2912cb1	1	// SPDX-License-Identifier: GPL-2.0-only
0a0c3b5a DHG	2	/*
	3	* drivers/uio/uio_dmem_genirq.c
	4	*
	5	* Userspace I/O platform driver with generic IRQ handling code.
	6	*
	7	* Copyright (C) 2012 Damian Hobson-Garcia
	8	*
	9	* Based on uio_pdrv_genirq.c by Magnus Damm
0a0c3b5a DHG	10	*/
	11
	12	#include <linux/platform_device.h>
	13	#include <linux/uio_driver.h>
	14	#include <linux/spinlock.h>
	15	#include <linux/bitops.h>
	16	#include <linux/module.h>
	17	#include <linux/interrupt.h>
	18	#include <linux/platform_data/uio_dmem_genirq.h>
	19	#include <linux/stringify.h>
	20	#include <linux/pm_runtime.h>
	21	#include <linux/dma-mapping.h>
	22	#include <linux/slab.h>
415abcdf	23	#include <linux/irq.h>
0a0c3b5a DHG	24
	25	#include <linux/of.h>
	26	#include <linux/of_platform.h>
	27	#include <linux/of_address.h>
	28
	29	#define DRIVER_NAME "uio_dmem_genirq"
87c4d1a7	30	#define DMEM_MAP_ERROR (~0)
0a0c3b5a DHG	31
	32	struct uio_dmem_genirq_platdata {
	33	struct uio_info *uioinfo;
	34	spinlock_t lock;
	35	unsigned long flags;
	36	struct platform_device *pdev;
	37	unsigned int dmem_region_start;
	38	unsigned int num_dmem_regions;
24fce61b	39	void *dmem_region_vaddr[MAX_UIO_MAPS];
0a0c3b5a DHG	40	struct mutex alloc_lock;
	41	unsigned int refcnt;
	42	};
	43
	44	static int uio_dmem_genirq_open(struct uio_info info, struct inode inode)
	45	{
	46	struct uio_dmem_genirq_platdata *priv = info->priv;
	47	struct uio_mem *uiomem;
24fce61b	48	int dmem_region = priv->dmem_region_start;
0a0c3b5a DHG	49
	50	uiomem = &priv->uioinfo->mem[priv->dmem_region_start];
	51
	52	mutex_lock(&priv->alloc_lock);
	53	while (!priv->refcnt && uiomem < &priv->uioinfo->mem[MAX_UIO_MAPS]) {
	54	void *addr;
	55	if (!uiomem->size)
	56	break;
	57
	58	addr = dma_alloc_coherent(&priv->pdev->dev, uiomem->size,
	59	(dma_addr_t *)&uiomem->addr, GFP_KERNEL);
	60	if (!addr) {
87c4d1a7	61	uiomem->addr = DMEM_MAP_ERROR;
0a0c3b5a	62	}
24fce61b	63	priv->dmem_region_vaddr[dmem_region++] = addr;
0a0c3b5a DHG	64	++uiomem;
	65	}
	66	priv->refcnt++;
	67
	68	mutex_unlock(&priv->alloc_lock);
	69	/* Wait until the Runtime PM code has woken up the device */
	70	pm_runtime_get_sync(&priv->pdev->dev);
16130978	71	return 0;
0a0c3b5a DHG	72	}
	73
	74	static int uio_dmem_genirq_release(struct uio_info info, struct inode inode)
	75	{
	76	struct uio_dmem_genirq_platdata *priv = info->priv;
	77	struct uio_mem *uiomem;
24fce61b	78	int dmem_region = priv->dmem_region_start;
0a0c3b5a DHG	79
	80	/* Tell the Runtime PM code that the device has become idle */
	81	pm_runtime_put_sync(&priv->pdev->dev);
	82
	83	uiomem = &priv->uioinfo->mem[priv->dmem_region_start];
	84
	85	mutex_lock(&priv->alloc_lock);
	86
	87	priv->refcnt--;
	88	while (!priv->refcnt && uiomem < &priv->uioinfo->mem[MAX_UIO_MAPS]) {
	89	if (!uiomem->size)
	90	break;
439926c8 DHG	91	if (priv->dmem_region_vaddr[dmem_region]) {
	92	dma_free_coherent(&priv->pdev->dev, uiomem->size,
	93	priv->dmem_region_vaddr[dmem_region],
	94	uiomem->addr);
	95	}
87c4d1a7	96	uiomem->addr = DMEM_MAP_ERROR;
439926c8	97	++dmem_region;
0a0c3b5a DHG	98	++uiomem;
	99	}
	100
	101	mutex_unlock(&priv->alloc_lock);
	102	return 0;
	103	}
	104
	105	static irqreturn_t uio_dmem_genirq_handler(int irq, struct uio_info *dev_info)
	106	{
	107	struct uio_dmem_genirq_platdata *priv = dev_info->priv;
	108
	109	/* Just disable the interrupt in the interrupt controller, and
	110	* remember the state so we can allow user space to enable it later.
	111	*/
	112
	113	if (!test_and_set_bit(0, &priv->flags))
	114	disable_irq_nosync(irq);
	115
	116	return IRQ_HANDLED;
	117	}
	118
	119	static int uio_dmem_genirq_irqcontrol(struct uio_info *dev_info, s32 irq_on)
	120	{
	121	struct uio_dmem_genirq_platdata *priv = dev_info->priv;
	122	unsigned long flags;
	123
	124	/* Allow user space to enable and disable the interrupt
	125	* in the interrupt controller, but keep track of the
	126	* state to prevent per-irq depth damage.
	127	*
	128	* Serialize this operation to support multiple tasks.
	129	*/
	130
	131	spin_lock_irqsave(&priv->lock, flags);
	132	if (irq_on) {
	133	if (test_and_clear_bit(0, &priv->flags))
	134	enable_irq(dev_info->irq);
b7435128	135	spin_unlock_irqrestore(&priv->lock, flags);
0a0c3b5a	136	} else {
b7435128 JJB	137	if (!test_and_set_bit(0, &priv->flags)) {
b7435128 JJB	138	spin_unlock_irqrestore(&priv->lock, flags);
0a0c3b5a	139	disable_irq(dev_info->irq);
b7435128	140	}
0a0c3b5a	141	}
0a0c3b5a DHG	142
	143	return 0;
	144	}
	145
ba022851 AA	146	static void uio_dmem_genirq_pm_disable(void *data)
	147	{
	148	struct device *dev = data;
	149
	150	pm_runtime_disable(dev);
	151	}
	152
0a0c3b5a DHG	153	static int uio_dmem_genirq_probe(struct platform_device *pdev)
0a0c3b5a DHG	154	{
31f52213	155	struct uio_dmem_genirq_pdata *pdata = dev_get_platdata(&pdev->dev);
0a0c3b5a DHG	156	struct uio_info *uioinfo = &pdata->uioinfo;
	157	struct uio_dmem_genirq_platdata *priv;
	158	struct uio_mem *uiomem;
	159	int ret = -EINVAL;
	160	int i;
	161
d5185c4e	162	if (pdev->dev.of_node) {
0a0c3b5a	163	/* alloc uioinfo for one device */
44dccc4a	164	uioinfo = devm_kzalloc(&pdev->dev, sizeof(*uioinfo), GFP_KERNEL);
0a0c3b5a	165	if (!uioinfo) {
0a0c3b5a	166	dev_err(&pdev->dev, "unable to kmalloc\n");
44dccc4a	167	return -ENOMEM;
0a0c3b5a	168	}
52e2dc2c RH	169	uioinfo->name = devm_kasprintf(&pdev->dev, GFP_KERNEL, "%pOFn",
52e2dc2c RH	170	pdev->dev.of_node);
0a0c3b5a	171	uioinfo->version = "devicetree";
0a0c3b5a DHG	172	}
	173
	174	if (!uioinfo \|\| !uioinfo->name \|\| !uioinfo->version) {
	175	dev_err(&pdev->dev, "missing platform_data\n");
44dccc4a	176	return -EINVAL;
0a0c3b5a DHG	177	}
	178
	179	if (uioinfo->handler \|\| uioinfo->irqcontrol \|\|
	180	uioinfo->irq_flags & IRQF_SHARED) {
	181	dev_err(&pdev->dev, "interrupt configuration error\n");
44dccc4a	182	return -EINVAL;
0a0c3b5a DHG	183	}
0a0c3b5a DHG	184
44dccc4a	185	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
0a0c3b5a	186	if (!priv) {
0a0c3b5a	187	dev_err(&pdev->dev, "unable to kmalloc\n");
44dccc4a	188	return -ENOMEM;
0a0c3b5a DHG	189	}
	190
	191	dma_set_coherent_mask(&pdev->dev, DMA_BIT_MASK(32));
	192
	193	priv->uioinfo = uioinfo;
	194	spin_lock_init(&priv->lock);
	195	priv->flags = 0; /* interrupt is enabled to begin with */
	196	priv->pdev = pdev;
	197	mutex_init(&priv->alloc_lock);
	198
	199	if (!uioinfo->irq) {
3ec1bd76	200	/* Multiple IRQs are not supported */
0a0c3b5a	201	ret = platform_get_irq(pdev, 0);
3ec1bd76 AA	202	if (ret == -ENXIO && pdev->dev.of_node)
	203	ret = UIO_IRQ_NONE;
	204	else if (ret < 0)
44dccc4a	205	return ret;
0a0c3b5a DHG	206	uioinfo->irq = ret;
0a0c3b5a DHG	207	}
415abcdf TJ	208
	209	if (uioinfo->irq) {
	210	struct irq_data *irq_data = irq_get_irq_data(uioinfo->irq);
	211
	212	/*
	213	* If a level interrupt, dont do lazy disable. Otherwise the
	214	* irq will fire again since clearing of the actual cause, on
	215	* device level, is done in userspace
	216	* irqd_is_level_type() isn't used since isn't valid until
	217	* irq is configured.
	218	*/
	219	if (irq_data &&
	220	irqd_get_trigger_type(irq_data) & IRQ_TYPE_LEVEL_MASK) {
	221	dev_dbg(&pdev->dev, "disable lazy unmask\n");
	222	irq_set_status_flags(uioinfo->irq, IRQ_DISABLE_UNLAZY);
	223	}
	224	}
	225
0a0c3b5a DHG	226	uiomem = &uioinfo->mem[0];
	227
	228	for (i = 0; i < pdev->num_resources; ++i) {
	229	struct resource *r = &pdev->resource[i];
	230
	231	if (r->flags != IORESOURCE_MEM)
	232	continue;
	233
	234	if (uiomem >= &uioinfo->mem[MAX_UIO_MAPS]) {
	235	dev_warn(&pdev->dev, "device has more than "
	236	__stringify(MAX_UIO_MAPS)
	237	" I/O memory resources.\n");
	238	break;
	239	}
	240
	241	uiomem->memtype = UIO_MEM_PHYS;
	242	uiomem->addr = r->start;
	243	uiomem->size = resource_size(r);
	244	++uiomem;
	245	}
	246
4d31a258	247	priv->dmem_region_start = uiomem - &uioinfo->mem[0];
0a0c3b5a DHG	248	priv->num_dmem_regions = pdata->num_dynamic_regions;
	249
	250	for (i = 0; i < pdata->num_dynamic_regions; ++i) {
	251	if (uiomem >= &uioinfo->mem[MAX_UIO_MAPS]) {
	252	dev_warn(&pdev->dev, "device has more than "
	253	__stringify(MAX_UIO_MAPS)
	254	" dynamic and fixed memory regions.\n");
	255	break;
	256	}
	257	uiomem->memtype = UIO_MEM_PHYS;
87c4d1a7	258	uiomem->addr = DMEM_MAP_ERROR;
0a0c3b5a DHG	259	uiomem->size = pdata->dynamic_region_sizes[i];
	260	++uiomem;
	261	}
	262
	263	while (uiomem < &uioinfo->mem[MAX_UIO_MAPS]) {
	264	uiomem->size = 0;
	265	++uiomem;
	266	}
	267
	268	/* This driver requires no hardware specific kernel code to handle
	269	* interrupts. Instead, the interrupt handler simply disables the
	270	* interrupt in the interrupt controller. User space is responsible
	271	* for performing hardware specific acknowledge and re-enabling of
	272	* the interrupt in the interrupt controller.
	273	*
	274	* Interrupt sharing is not supported.
	275	*/
	276
	277	uioinfo->handler = uio_dmem_genirq_handler;
	278	uioinfo->irqcontrol = uio_dmem_genirq_irqcontrol;
	279	uioinfo->open = uio_dmem_genirq_open;
	280	uioinfo->release = uio_dmem_genirq_release;
	281	uioinfo->priv = priv;
	282
	283	/* Enable Runtime PM for this device:
	284	* The device starts in suspended state to allow the hardware to be
	285	* turned off by default. The Runtime PM bus code should power on the
	286	* hardware and enable clocks at open().
	287	*/
	288	pm_runtime_enable(&pdev->dev);
	289
ba022851 AA	290	ret = devm_add_action_or_reset(&pdev->dev, uio_dmem_genirq_pm_disable, &pdev->dev);
ba022851 AA	291	if (ret)
44dccc4a	292	return ret;
0a0c3b5a	293
ba022851	294	return devm_uio_register_device(&pdev->dev, priv->uioinfo);
0a0c3b5a DHG	295	}
	296
	297	static int uio_dmem_genirq_runtime_nop(struct device *dev)
	298	{
	299	/* Runtime PM callback shared between ->runtime_suspend()
	300	* and ->runtime_resume(). Simply returns success.
	301	*
	302	* In this driver pm_runtime_get_sync() and pm_runtime_put_sync()
	303	* are used at open() and release() time. This allows the
	304	* Runtime PM code to turn off power to the device while the
	305	* device is unused, ie before open() and after release().
	306	*
	307	* This Runtime PM callback does not need to save or restore
	308	* any registers since user space is responsbile for hardware
	309	* register reinitialization after open().
	310	*/
	311	return 0;
	312	}
	313
	314	static const struct dev_pm_ops uio_dmem_genirq_dev_pm_ops = {
	315	.runtime_suspend = uio_dmem_genirq_runtime_nop,
	316	.runtime_resume = uio_dmem_genirq_runtime_nop,
	317	};
	318
	319	#ifdef CONFIG_OF
	320	static const struct of_device_id uio_of_genirq_match[] = {
	321	{ /* empty for now */ },
	322	};
	323	MODULE_DEVICE_TABLE(of, uio_of_genirq_match);
0a0c3b5a DHG	324	#endif
	325
	326	static struct platform_driver uio_dmem_genirq = {
	327	.probe = uio_dmem_genirq_probe,
0a0c3b5a DHG	328	.driver = {
0a0c3b5a DHG	329	.name = DRIVER_NAME,
0a0c3b5a	330	.pm = &uio_dmem_genirq_dev_pm_ops,
07779711	331	.of_match_table = of_match_ptr(uio_of_genirq_match),
0a0c3b5a DHG	332	},
	333	};
	334
	335	module_platform_driver(uio_dmem_genirq);
	336
	337	MODULE_AUTHOR("Damian Hobson-Garcia");
	338	MODULE_DESCRIPTION("Userspace I/O platform driver with dynamic memory.");
	339	MODULE_LICENSE("GPL v2");
	340	MODULE_ALIAS("platform:" DRIVER_NAME);