[linux-2.6-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/irq.h>

#include <linux/of.h>
#include <linux/mod_devicetable.h>
#include <linux/property.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 void uio_pdrv_genirq_cleanup(void *data)
{
	struct device *dev = data;

	pm_runtime_disable(dev);
}

static int uio_pdrv_genirq_probe(struct platform_device *pdev)
{
	struct uio_info *uioinfo = dev_get_platdata(&pdev->dev);
	struct fwnode_handle *node = dev_fwnode(&pdev->dev);
	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 (!device_property_read_string(&pdev->dev, "linux,uio-name", &name))
			uioinfo->name = devm_kstrdup(&pdev->dev, name, GFP_KERNEL);
		else
			uioinfo->name = devm_kasprintf(&pdev->dev, GFP_KERNEL,
						       "%pfwP", 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_optional(pdev, 0);
		uioinfo->irq = ret;
		if (ret == -ENXIO)
			uioinfo->irq = UIO_IRQ_NONE;
		else if (ret == -EPROBE_DEFER)
			return ret;
		else if (ret < 0) {
			dev_err(&pdev->dev, "failed to get IRQ\n");
			return 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 & PAGE_MASK;
		uiomem->offs = r->start & ~PAGE_MASK;
		uiomem->size = (uiomem->offs + resource_size(r)
				+ PAGE_SIZE - 1) & PAGE_MASK;
		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 = devm_add_action_or_reset(&pdev->dev, uio_pdrv_genirq_cleanup,
				       &pdev->dev);
	if (ret)
		return ret;

	ret = devm_uio_register_device(&pdev->dev, priv->uioinfo);
	if (ret)
		dev_err(&pdev->dev, "unable to register uio device\n");

	return ret;
}

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,
	.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>
415abcdf	23	#include <linux/irq.h>
c767db0a	24
27760f86	25	#include <linux/of.h>
90fa0280 CP	26	#include <linux/mod_devicetable.h>
90fa0280 CP	27	#include <linux/property.h>
27760f86	28
c767db0a MD	29	#define DRIVER_NAME "uio_pdrv_genirq"
	30
	31	struct uio_pdrv_genirq_platdata {
	32	struct uio_info *uioinfo;
	33	spinlock_t lock;
	34	unsigned long flags;
af76756e	35	struct platform_device *pdev;
c767db0a MD	36	};
c767db0a MD	37
34cb2752 VD	38	/* Bits in uio_pdrv_genirq_platdata.flags */
	39	enum {
	40	UIO_IRQ_DISABLED = 0,
	41	};
	42
af76756e MD	43	static int uio_pdrv_genirq_open(struct uio_info info, struct inode inode)
	44	{
	45	struct uio_pdrv_genirq_platdata *priv = info->priv;
	46
	47	/* Wait until the Runtime PM code has woken up the device */
	48	pm_runtime_get_sync(&priv->pdev->dev);
	49	return 0;
	50	}
	51
	52	static int uio_pdrv_genirq_release(struct uio_info info, struct inode inode)
	53	{
	54	struct uio_pdrv_genirq_platdata *priv = info->priv;
	55
	56	/* Tell the Runtime PM code that the device has become idle */
	57	pm_runtime_put_sync(&priv->pdev->dev);
	58	return 0;
	59	}
	60
c767db0a MD	61	static irqreturn_t uio_pdrv_genirq_handler(int irq, struct uio_info *dev_info)
	62	{
	63	struct uio_pdrv_genirq_platdata *priv = dev_info->priv;
	64
	65	/* Just disable the interrupt in the interrupt controller, and
	66	* remember the state so we can allow user space to enable it later.
	67	*/
	68
34cb2752 VD	69	spin_lock(&priv->lock);
34cb2752 VD	70	if (!__test_and_set_bit(UIO_IRQ_DISABLED, &priv->flags))
c767db0a	71	disable_irq_nosync(irq);
34cb2752	72	spin_unlock(&priv->lock);
c767db0a MD	73
	74	return IRQ_HANDLED;
	75	}
	76
	77	static int uio_pdrv_genirq_irqcontrol(struct uio_info *dev_info, s32 irq_on)
	78	{
	79	struct uio_pdrv_genirq_platdata *priv = dev_info->priv;
	80	unsigned long flags;
	81
	82	/* Allow user space to enable and disable the interrupt
	83	* in the interrupt controller, but keep track of the
	84	* state to prevent per-irq depth damage.
	85	*
34cb2752 VD	86	* Serialize this operation to support multiple tasks and concurrency
34cb2752 VD	87	* with irq handler on SMP systems.
c767db0a MD	88	*/
	89
	90	spin_lock_irqsave(&priv->lock, flags);
	91	if (irq_on) {
34cb2752	92	if (__test_and_clear_bit(UIO_IRQ_DISABLED, &priv->flags))
c767db0a MD	93	enable_irq(dev_info->irq);
c767db0a MD	94	} else {
34cb2752 VD	95	if (!__test_and_set_bit(UIO_IRQ_DISABLED, &priv->flags))
34cb2752 VD	96	disable_irq_nosync(dev_info->irq);
c767db0a MD	97	}
	98	spin_unlock_irqrestore(&priv->lock, flags);
	99
	100	return 0;
	101	}
	102
eff1dd87 AA	103	static void uio_pdrv_genirq_cleanup(void *data)
	104	{
	105	struct device *dev = data;
	106
	107	pm_runtime_disable(dev);
	108	}
	109
c767db0a MD	110	static int uio_pdrv_genirq_probe(struct platform_device *pdev)
c767db0a MD	111	{
08cb2e21	112	struct uio_info *uioinfo = dev_get_platdata(&pdev->dev);
90fa0280	113	struct fwnode_handle *node = dev_fwnode(&pdev->dev);
c767db0a MD	114	struct uio_pdrv_genirq_platdata *priv;
	115	struct uio_mem *uiomem;
	116	int ret = -EINVAL;
	117	int i;
	118
b0297622 DM	119	if (node) {
	120	const char *name;
	121
27760f86	122	/* alloc uioinfo for one device */
e6789cd3 MS	123	uioinfo = devm_kzalloc(&pdev->dev, sizeof(*uioinfo),
e6789cd3 MS	124	GFP_KERNEL);
27760f86	125	if (!uioinfo) {
27760f86	126	dev_err(&pdev->dev, "unable to kmalloc\n");
e6789cd3	127	return -ENOMEM;
27760f86	128	}
b0297622	129
90fa0280	130	if (!device_property_read_string(&pdev->dev, "linux,uio-name", &name))
b0297622 DM	131	uioinfo->name = devm_kstrdup(&pdev->dev, name, GFP_KERNEL);
	132	else
	133	uioinfo->name = devm_kasprintf(&pdev->dev, GFP_KERNEL,
90fa0280	134	"%pfwP", node);
b0297622	135
27760f86	136	uioinfo->version = "devicetree";
27760f86	137	/* Multiple IRQs are not supported */
27760f86 HK	138	}
27760f86 HK	139
c767db0a MD	140	if (!uioinfo \|\| !uioinfo->name \|\| !uioinfo->version) {
c767db0a MD	141	dev_err(&pdev->dev, "missing platform_data\n");
e6789cd3	142	return ret;
c767db0a MD	143	}
c767db0a MD	144
e543ae89 MF	145	if (uioinfo->handler \|\| uioinfo->irqcontrol \|\|
e543ae89 MF	146	uioinfo->irq_flags & IRQF_SHARED) {
c767db0a	147	dev_err(&pdev->dev, "interrupt configuration error\n");
e6789cd3	148	return ret;
c767db0a MD	149	}
c767db0a MD	150
e6789cd3	151	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
c767db0a	152	if (!priv) {
c767db0a	153	dev_err(&pdev->dev, "unable to kmalloc\n");
e6789cd3	154	return -ENOMEM;
c767db0a MD	155	}
	156
	157	priv->uioinfo = uioinfo;
	158	spin_lock_init(&priv->lock);
	159	priv->flags = 0; /* interrupt is enabled to begin with */
af76756e	160	priv->pdev = pdev;
c767db0a	161
94ca629e	162	if (!uioinfo->irq) {
324ac45f	163	ret = platform_get_irq_optional(pdev, 0);
e3a3c3a2	164	uioinfo->irq = ret;
bf12fdf0	165	if (ret == -ENXIO)
e3a3c3a2	166	uioinfo->irq = UIO_IRQ_NONE;
34bc4f46 OR	167	else if (ret == -EPROBE_DEFER)
34bc4f46 OR	168	return ret;
e3a3c3a2	169	else if (ret < 0) {
94ca629e	170	dev_err(&pdev->dev, "failed to get IRQ\n");
e6789cd3	171	return ret;
94ca629e	172	}
94ca629e	173	}
e3a3c3a2	174
415abcdf TJ	175	if (uioinfo->irq) {
	176	struct irq_data *irq_data = irq_get_irq_data(uioinfo->irq);
	177
	178	/*
	179	* If a level interrupt, dont do lazy disable. Otherwise the
	180	* irq will fire again since clearing of the actual cause, on
	181	* device level, is done in userspace
	182	* irqd_is_level_type() isn't used since isn't valid until
	183	* irq is configured.
	184	*/
	185	if (irq_data &&
	186	irqd_get_trigger_type(irq_data) & IRQ_TYPE_LEVEL_MASK) {
	187	dev_dbg(&pdev->dev, "disable lazy unmask\n");
	188	irq_set_status_flags(uioinfo->irq, IRQ_DISABLE_UNLAZY);
	189	}
	190	}
	191
c767db0a MD	192	uiomem = &uioinfo->mem[0];
	193
	194	for (i = 0; i < pdev->num_resources; ++i) {
	195	struct resource *r = &pdev->resource[i];
	196
	197	if (r->flags != IORESOURCE_MEM)
	198	continue;
	199
	200	if (uiomem >= &uioinfo->mem[MAX_UIO_MAPS]) {
	201	dev_warn(&pdev->dev, "device has more than "
	202	__stringify(MAX_UIO_MAPS)
	203	" I/O memory resources.\n");
	204	break;
	205	}
	206
	207	uiomem->memtype = UIO_MEM_PHYS;
7aca462b EH	208	uiomem->addr = r->start & PAGE_MASK;
	209	uiomem->offs = r->start & ~PAGE_MASK;
	210	uiomem->size = (uiomem->offs + resource_size(r)
	211	+ PAGE_SIZE - 1) & PAGE_MASK;
ecd43c0d	212	uiomem->name = r->name;
c767db0a MD	213	++uiomem;
	214	}
	215
	216	while (uiomem < &uioinfo->mem[MAX_UIO_MAPS]) {
	217	uiomem->size = 0;
	218	++uiomem;
	219	}
	220
	221	/* This driver requires no hardware specific kernel code to handle
	222	* interrupts. Instead, the interrupt handler simply disables the
	223	* interrupt in the interrupt controller. User space is responsible
	224	* for performing hardware specific acknowledge and re-enabling of
	225	* the interrupt in the interrupt controller.
	226	*
	227	* Interrupt sharing is not supported.
	228	*/
	229
c767db0a MD	230	uioinfo->handler = uio_pdrv_genirq_handler;
c767db0a MD	231	uioinfo->irqcontrol = uio_pdrv_genirq_irqcontrol;
af76756e MD	232	uioinfo->open = uio_pdrv_genirq_open;
af76756e MD	233	uioinfo->release = uio_pdrv_genirq_release;
c767db0a MD	234	uioinfo->priv = priv;
c767db0a MD	235
af76756e MD	236	/* Enable Runtime PM for this device:
	237	* The device starts in suspended state to allow the hardware to be
	238	* turned off by default. The Runtime PM bus code should power on the
	239	* hardware and enable clocks at open().
	240	*/
	241	pm_runtime_enable(&pdev->dev);
	242
eff1dd87 AA	243	ret = devm_add_action_or_reset(&pdev->dev, uio_pdrv_genirq_cleanup,
	244	&pdev->dev);
	245	if (ret)
e6789cd3	246	return ret;
c767db0a	247
eff1dd87 AA	248	ret = devm_uio_register_device(&pdev->dev, priv->uioinfo);
	249	if (ret)
	250	dev_err(&pdev->dev, "unable to register uio device\n");
47296b19	251
eff1dd87	252	return ret;
c767db0a MD	253	}
c767db0a MD	254
af76756e MD	255	static int uio_pdrv_genirq_runtime_nop(struct device *dev)
	256	{
	257	/* Runtime PM callback shared between ->runtime_suspend()
	258	* and ->runtime_resume(). Simply returns success.
	259	*
	260	* In this driver pm_runtime_get_sync() and pm_runtime_put_sync()
	261	* are used at open() and release() time. This allows the
	262	* Runtime PM code to turn off power to the device while the
	263	* device is unused, ie before open() and after release().
	264	*
	265	* This Runtime PM callback does not need to save or restore
	266	* any registers since user space is responsbile for hardware
	267	* register reinitialization after open().
	268	*/
	269	return 0;
	270	}
	271
47145210	272	static const struct dev_pm_ops uio_pdrv_genirq_dev_pm_ops = {
af76756e MD	273	.runtime_suspend = uio_pdrv_genirq_runtime_nop,
	274	.runtime_resume = uio_pdrv_genirq_runtime_nop,
	275	};
	276
27760f86	277	#ifdef CONFIG_OF
05c3e0bb PM	278	static struct of_device_id uio_of_genirq_match[] = {
	279	{ /* This is filled with module_parm */ },
	280	{ /* Sentinel */ },
27760f86 HK	281	};
27760f86 HK	282	MODULE_DEVICE_TABLE(of, uio_of_genirq_match);
05c3e0bb PM	283	module_param_string(of_id, uio_of_genirq_match[0].compatible, 128, 0);
05c3e0bb PM	284	MODULE_PARM_DESC(of_id, "Openfirmware id of the device to be handled by uio");
27760f86 HK	285	#endif
27760f86 HK	286
c767db0a MD	287	static struct platform_driver uio_pdrv_genirq = {
c767db0a MD	288	.probe = uio_pdrv_genirq_probe,
c767db0a MD	289	.driver = {
c767db0a MD	290	.name = DRIVER_NAME,
af76756e	291	.pm = &uio_pdrv_genirq_dev_pm_ops,
cee4fbd6	292	.of_match_table = of_match_ptr(uio_of_genirq_match),
c767db0a MD	293	},
	294	};
	295
11e3123d	296	module_platform_driver(uio_pdrv_genirq);
c767db0a MD	297
	298	MODULE_AUTHOR("Magnus Damm");
	299	MODULE_DESCRIPTION("Userspace I/O platform driver with generic IRQ handling");
	300	MODULE_LICENSE("GPL v2");
	301	MODULE_ALIAS("platform:" DRIVER_NAME);