drivers/uio/uio_pdrv_genirq.c - linux - Git at Google

 // 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);
	// 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);