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

// SPDX-License-Identifier: GPL-2.0-only
/*
 * 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.
 */

#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 device_node *node = pdev->dev.of_node;
	struct uio_pdrv_genirq_platdata *priv;
	struct uio_mem *uiomem;
	int ret = -EINVAL;
	int i;

	if (node) {
		const char *name;

		/* 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;
		}

		if (!of_property_read_string(node, "linux,uio-name", &name))
			uioinfo->name = devm_kstrdup(&pdev->dev, name, GFP_KERNEL);
		else
			uioinfo->name = devm_kasprintf(&pdev->dev, GFP_KERNEL,
						       "%pOFn", 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
d2912cb1	1	// SPDX-License-Identifier: GPL-2.0-only
c767db0a MD	2	/*
	3	* drivers/uio/uio_pdrv_genirq.c
	4	*
	5	* Userspace I/O platform driver with generic IRQ handling code.
	6	*
	7	* Copyright (C) 2008 Magnus Damm
	8	*
	9	* Based on uio_pdrv.c by Uwe Kleine-Koenig,
	10	* Copyright (C) 2008 by Digi International Inc.
	11	* All rights reserved.
c767db0a MD	12	*/
	13
	14	#include <linux/platform_device.h>
	15	#include <linux/uio_driver.h>
	16	#include <linux/spinlock.h>
	17	#include <linux/bitops.h>
2949ead4	18	#include <linux/module.h>
c767db0a MD	19	#include <linux/interrupt.h>
c767db0a MD	20	#include <linux/stringify.h>
af76756e	21	#include <linux/pm_runtime.h>
5a0e3ad6	22	#include <linux/slab.h>
c767db0a	23
27760f86 HK	24	#include <linux/of.h>
	25	#include <linux/of_platform.h>
	26	#include <linux/of_address.h>
	27
c767db0a MD	28	#define DRIVER_NAME "uio_pdrv_genirq"
	29
	30	struct uio_pdrv_genirq_platdata {
	31	struct uio_info *uioinfo;
	32	spinlock_t lock;
	33	unsigned long flags;
af76756e	34	struct platform_device *pdev;
c767db0a MD	35	};
c767db0a MD	36
34cb2752 VD	37	/* Bits in uio_pdrv_genirq_platdata.flags */
	38	enum {
	39	UIO_IRQ_DISABLED = 0,
	40	};
	41
af76756e MD	42	static int uio_pdrv_genirq_open(struct uio_info info, struct inode inode)
	43	{
	44	struct uio_pdrv_genirq_platdata *priv = info->priv;
	45
	46	/* Wait until the Runtime PM code has woken up the device */
	47	pm_runtime_get_sync(&priv->pdev->dev);
	48	return 0;
	49	}
	50
	51	static int uio_pdrv_genirq_release(struct uio_info info, struct inode inode)
	52	{
	53	struct uio_pdrv_genirq_platdata *priv = info->priv;
	54
	55	/* Tell the Runtime PM code that the device has become idle */
	56	pm_runtime_put_sync(&priv->pdev->dev);
	57	return 0;
	58	}
	59
c767db0a MD	60	static irqreturn_t uio_pdrv_genirq_handler(int irq, struct uio_info *dev_info)
	61	{
	62	struct uio_pdrv_genirq_platdata *priv = dev_info->priv;
	63
	64	/* Just disable the interrupt in the interrupt controller, and
	65	* remember the state so we can allow user space to enable it later.
	66	*/
	67
34cb2752 VD	68	spin_lock(&priv->lock);
34cb2752 VD	69	if (!__test_and_set_bit(UIO_IRQ_DISABLED, &priv->flags))
c767db0a	70	disable_irq_nosync(irq);
34cb2752	71	spin_unlock(&priv->lock);
c767db0a MD	72
	73	return IRQ_HANDLED;
	74	}
	75
	76	static int uio_pdrv_genirq_irqcontrol(struct uio_info *dev_info, s32 irq_on)
	77	{
	78	struct uio_pdrv_genirq_platdata *priv = dev_info->priv;
	79	unsigned long flags;
	80
	81	/* Allow user space to enable and disable the interrupt
	82	* in the interrupt controller, but keep track of the
	83	* state to prevent per-irq depth damage.
	84	*
34cb2752 VD	85	* Serialize this operation to support multiple tasks and concurrency
34cb2752 VD	86	* with irq handler on SMP systems.
c767db0a MD	87	*/
	88
	89	spin_lock_irqsave(&priv->lock, flags);
	90	if (irq_on) {
34cb2752	91	if (__test_and_clear_bit(UIO_IRQ_DISABLED, &priv->flags))
c767db0a MD	92	enable_irq(dev_info->irq);
c767db0a MD	93	} else {
34cb2752 VD	94	if (!__test_and_set_bit(UIO_IRQ_DISABLED, &priv->flags))
34cb2752 VD	95	disable_irq_nosync(dev_info->irq);
c767db0a MD	96	}
	97	spin_unlock_irqrestore(&priv->lock, flags);
	98
	99	return 0;
	100	}
	101
	102	static int uio_pdrv_genirq_probe(struct platform_device *pdev)
	103	{
08cb2e21	104	struct uio_info *uioinfo = dev_get_platdata(&pdev->dev);
b0297622	105	struct device_node *node = pdev->dev.of_node;
c767db0a MD	106	struct uio_pdrv_genirq_platdata *priv;
	107	struct uio_mem *uiomem;
	108	int ret = -EINVAL;
	109	int i;
	110
b0297622 DM	111	if (node) {
	112	const char *name;
	113
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	}
b0297622 DM	121
	122	if (!of_property_read_string(node, "linux,uio-name", &name))
	123	uioinfo->name = devm_kstrdup(&pdev->dev, name, GFP_KERNEL);
	124	else
	125	uioinfo->name = devm_kasprintf(&pdev->dev, GFP_KERNEL,
	126	"%pOFn", node);
	127
27760f86	128	uioinfo->version = "devicetree";
27760f86	129	/* Multiple IRQs are not supported */
27760f86 HK	130	}
27760f86 HK	131
c767db0a MD	132	if (!uioinfo \|\| !uioinfo->name \|\| !uioinfo->version) {
c767db0a MD	133	dev_err(&pdev->dev, "missing platform_data\n");
e6789cd3	134	return ret;
c767db0a MD	135	}
c767db0a MD	136
e543ae89 MF	137	if (uioinfo->handler \|\| uioinfo->irqcontrol \|\|
e543ae89 MF	138	uioinfo->irq_flags & IRQF_SHARED) {
c767db0a	139	dev_err(&pdev->dev, "interrupt configuration error\n");
e6789cd3	140	return ret;
c767db0a MD	141	}
c767db0a MD	142
e6789cd3	143	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
c767db0a	144	if (!priv) {
c767db0a	145	dev_err(&pdev->dev, "unable to kmalloc\n");
e6789cd3	146	return -ENOMEM;
c767db0a MD	147	}
	148
	149	priv->uioinfo = uioinfo;
	150	spin_lock_init(&priv->lock);
	151	priv->flags = 0; /* interrupt is enabled to begin with */
af76756e	152	priv->pdev = pdev;
c767db0a	153
94ca629e BS	154	if (!uioinfo->irq) {
94ca629e BS	155	ret = platform_get_irq(pdev, 0);
e3a3c3a2 PM	156	uioinfo->irq = ret;
	157	if (ret == -ENXIO && pdev->dev.of_node)
	158	uioinfo->irq = UIO_IRQ_NONE;
	159	else if (ret < 0) {
94ca629e	160	dev_err(&pdev->dev, "failed to get IRQ\n");
e6789cd3	161	return ret;
94ca629e	162	}
94ca629e	163	}
e3a3c3a2	164
c767db0a MD	165	uiomem = &uioinfo->mem[0];
	166
	167	for (i = 0; i < pdev->num_resources; ++i) {
	168	struct resource *r = &pdev->resource[i];
	169
	170	if (r->flags != IORESOURCE_MEM)
	171	continue;
	172
	173	if (uiomem >= &uioinfo->mem[MAX_UIO_MAPS]) {
	174	dev_warn(&pdev->dev, "device has more than "
	175	__stringify(MAX_UIO_MAPS)
	176	" I/O memory resources.\n");
	177	break;
	178	}
	179
	180	uiomem->memtype = UIO_MEM_PHYS;
	181	uiomem->addr = r->start;
28f65c11	182	uiomem->size = resource_size(r);
ecd43c0d	183	uiomem->name = r->name;
c767db0a MD	184	++uiomem;
	185	}
	186
	187	while (uiomem < &uioinfo->mem[MAX_UIO_MAPS]) {
	188	uiomem->size = 0;
	189	++uiomem;
	190	}
	191
	192	/* This driver requires no hardware specific kernel code to handle
	193	* interrupts. Instead, the interrupt handler simply disables the
	194	* interrupt in the interrupt controller. User space is responsible
	195	* for performing hardware specific acknowledge and re-enabling of
	196	* the interrupt in the interrupt controller.
	197	*
	198	* Interrupt sharing is not supported.
	199	*/
	200
c767db0a MD	201	uioinfo->handler = uio_pdrv_genirq_handler;
c767db0a MD	202	uioinfo->irqcontrol = uio_pdrv_genirq_irqcontrol;
af76756e MD	203	uioinfo->open = uio_pdrv_genirq_open;
af76756e MD	204	uioinfo->release = uio_pdrv_genirq_release;
c767db0a MD	205	uioinfo->priv = priv;
c767db0a MD	206
af76756e MD	207	/* Enable Runtime PM for this device:
	208	* The device starts in suspended state to allow the hardware to be
	209	* turned off by default. The Runtime PM bus code should power on the
	210	* hardware and enable clocks at open().
	211	*/
	212	pm_runtime_enable(&pdev->dev);
	213
c767db0a MD	214	ret = uio_register_device(&pdev->dev, priv->uioinfo);
	215	if (ret) {
	216	dev_err(&pdev->dev, "unable to register uio device\n");
e6789cd3 MS	217	pm_runtime_disable(&pdev->dev);
e6789cd3 MS	218	return ret;
c767db0a MD	219	}
	220
	221	platform_set_drvdata(pdev, priv);
	222	return 0;
c767db0a MD	223	}
	224
	225	static int uio_pdrv_genirq_remove(struct platform_device *pdev)
	226	{
	227	struct uio_pdrv_genirq_platdata *priv = platform_get_drvdata(pdev);
	228
	229	uio_unregister_device(priv->uioinfo);
af76756e	230	pm_runtime_disable(&pdev->dev);
47296b19 JZ	231
	232	priv->uioinfo->handler = NULL;
	233	priv->uioinfo->irqcontrol = NULL;
	234
c767db0a MD	235	return 0;
	236	}
	237
af76756e MD	238	static int uio_pdrv_genirq_runtime_nop(struct device *dev)
	239	{
	240	/* Runtime PM callback shared between ->runtime_suspend()
	241	* and ->runtime_resume(). Simply returns success.
	242	*
	243	* In this driver pm_runtime_get_sync() and pm_runtime_put_sync()
	244	* are used at open() and release() time. This allows the
	245	* Runtime PM code to turn off power to the device while the
	246	* device is unused, ie before open() and after release().
	247	*
	248	* This Runtime PM callback does not need to save or restore
	249	* any registers since user space is responsbile for hardware
	250	* register reinitialization after open().
	251	*/
	252	return 0;
	253	}
	254
47145210	255	static const struct dev_pm_ops uio_pdrv_genirq_dev_pm_ops = {
af76756e MD	256	.runtime_suspend = uio_pdrv_genirq_runtime_nop,
	257	.runtime_resume = uio_pdrv_genirq_runtime_nop,
	258	};
	259
27760f86	260	#ifdef CONFIG_OF
05c3e0bb PM	261	static struct of_device_id uio_of_genirq_match[] = {
	262	{ /* This is filled with module_parm */ },
	263	{ /* Sentinel */ },
27760f86 HK	264	};
27760f86 HK	265	MODULE_DEVICE_TABLE(of, uio_of_genirq_match);
05c3e0bb PM	266	module_param_string(of_id, uio_of_genirq_match[0].compatible, 128, 0);
05c3e0bb PM	267	MODULE_PARM_DESC(of_id, "Openfirmware id of the device to be handled by uio");
27760f86 HK	268	#endif
27760f86 HK	269
c767db0a MD	270	static struct platform_driver uio_pdrv_genirq = {
	271	.probe = uio_pdrv_genirq_probe,
	272	.remove = uio_pdrv_genirq_remove,
	273	.driver = {
	274	.name = DRIVER_NAME,
af76756e	275	.pm = &uio_pdrv_genirq_dev_pm_ops,
cee4fbd6	276	.of_match_table = of_match_ptr(uio_of_genirq_match),
c767db0a MD	277	},
	278	};
	279
11e3123d	280	module_platform_driver(uio_pdrv_genirq);
c767db0a MD	281
	282	MODULE_AUTHOR("Magnus Damm");
	283	MODULE_DESCRIPTION("Userspace I/O platform driver with generic IRQ handling");
	284	MODULE_LICENSE("GPL v2");
	285	MODULE_ALIAS("platform:" DRIVER_NAME);