drivers/uio/uio_sercos3.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 /* sercos3: UIO driver for the Automata Sercos III PCI card

    Copyright (C) 2008 Linutronix GmbH
      Author: John Ogness <john.ogness@linutronix.de>

    This is a straight-forward UIO driver, where interrupts are disabled
    by the interrupt handler and re-enabled via a write to the UIO device
    by the userspace-part.

    The only part that may seem odd is the use of a logical OR when
    storing and restoring enabled interrupts. This is done because the
    userspace-part could directly modify the Interrupt Enable Register
    at any time. To reduce possible conflicts, the kernel driver uses
    a logical OR to make more controlled changes (rather than blindly
    overwriting previous values).

    Race conditions exist if the userspace-part directly modifies the
    Interrupt Enable Register while in operation. The consequences are
    that certain interrupts would fail to be enabled or disabled. For
    this reason, the userspace-part should only directly modify the
    Interrupt Enable Register at the beginning (to get things going).
    The userspace-part can safely disable interrupts at any time using
    a write to the UIO device.
 */

 #include <linux/device.h>
 #include <linux/module.h>
 #include <linux/pci.h>
 #include <linux/uio_driver.h>
 #include <linux/io.h>
 #include <linux/slab.h>

 /* ID's for SERCOS III PCI card (PLX 9030) */
 #define SERCOS_SUB_VENDOR_ID  0x1971
 #define SERCOS_SUB_SYSID_3530 0x3530
 #define SERCOS_SUB_SYSID_3535 0x3535
 #define SERCOS_SUB_SYSID_3780 0x3780

 /* Interrupt Enable Register */
 #define IER0_OFFSET 0x08

 /* Interrupt Status Register */
 #define ISR0_OFFSET 0x18

 struct sercos3_priv {
 	u32 ier0_cache;
 	spinlock_t ier0_cache_lock;
 };

 /* this function assumes ier0_cache_lock is locked! */
 static void sercos3_disable_interrupts(struct uio_info *info,
 				       struct sercos3_priv *priv)
 {
 	void __iomem *ier0 = info->mem[3].internal_addr + IER0_OFFSET;

 	/* add enabled interrupts to cache */
 	priv->ier0_cache |= ioread32(ier0);

 	/* disable interrupts */
 	iowrite32(0, ier0);
 }

 /* this function assumes ier0_cache_lock is locked! */
 static void sercos3_enable_interrupts(struct uio_info *info,
 				      struct sercos3_priv *priv)
 {
 	void __iomem *ier0 = info->mem[3].internal_addr + IER0_OFFSET;

 	/* restore previously enabled interrupts */
 	iowrite32(ioread32(ier0) | priv->ier0_cache, ier0);
 	priv->ier0_cache = 0;
 }

 static irqreturn_t sercos3_handler(int irq, struct uio_info *info)
 {
 	struct sercos3_priv *priv = info->priv;
 	void __iomem *isr0 = info->mem[3].internal_addr + ISR0_OFFSET;
 	void __iomem *ier0 = info->mem[3].internal_addr + IER0_OFFSET;

 	if (!(ioread32(isr0) & ioread32(ier0)))
 		return IRQ_NONE;

 	spin_lock(&priv->ier0_cache_lock);
 	sercos3_disable_interrupts(info, priv);
 	spin_unlock(&priv->ier0_cache_lock);

 	return IRQ_HANDLED;
 }

 static int sercos3_irqcontrol(struct uio_info *info, s32 irq_on)
 {
 	struct sercos3_priv *priv = info->priv;

 	spin_lock_irq(&priv->ier0_cache_lock);
 	if (irq_on)
 		sercos3_enable_interrupts(info, priv);
 	else
 		sercos3_disable_interrupts(info, priv);
 	spin_unlock_irq(&priv->ier0_cache_lock);

 	return 0;
 }

 static int sercos3_setup_iomem(struct pci_dev *dev, struct uio_info *info,
 			       int n, int pci_bar)
 {
 	info->mem[n].addr = pci_resource_start(dev, pci_bar);
 	if (!info->mem[n].addr)
 		return -1;
 	info->mem[n].internal_addr = ioremap(pci_resource_start(dev, pci_bar),
 					     pci_resource_len(dev, pci_bar));
 	if (!info->mem[n].internal_addr)
 		return -1;
 	info->mem[n].size = pci_resource_len(dev, pci_bar);
 	info->mem[n].memtype = UIO_MEM_PHYS;
 	return 0;
 }

 static int sercos3_pci_probe(struct pci_dev *dev,
 				       const struct pci_device_id *id)
 {
 	struct uio_info *info;
 	struct sercos3_priv *priv;
 	int i;

 	info = devm_kzalloc(&dev->dev, sizeof(struct uio_info), GFP_KERNEL);
 	if (!info)
 		return -ENOMEM;

 	priv = devm_kzalloc(&dev->dev, sizeof(struct sercos3_priv), GFP_KERNEL);
 	if (!priv)
 		return -ENOMEM;

 	if (pci_enable_device(dev))
 		return -ENODEV;

 	if (pci_request_regions(dev, "sercos3"))
 		goto out_disable;

 	/* we only need PCI BAR's 0, 2, 3, 4, 5 */
 	if (sercos3_setup_iomem(dev, info, 0, 0))
 		goto out_unmap;
 	if (sercos3_setup_iomem(dev, info, 1, 2))
 		goto out_unmap;
 	if (sercos3_setup_iomem(dev, info, 2, 3))
 		goto out_unmap;
 	if (sercos3_setup_iomem(dev, info, 3, 4))
 		goto out_unmap;
 	if (sercos3_setup_iomem(dev, info, 4, 5))
 		goto out_unmap;

 	spin_lock_init(&priv->ier0_cache_lock);
 	info->priv = priv;
 	info->name = "Sercos_III_PCI";
 	info->version = "0.0.1";
 	info->irq = dev->irq;
 	info->irq_flags = IRQF_SHARED;
 	info->handler = sercos3_handler;
 	info->irqcontrol = sercos3_irqcontrol;

 	pci_set_drvdata(dev, info);

 	if (uio_register_device(&dev->dev, info))
 		goto out_unmap;

 	return 0;

 out_unmap:
 	for (i = 0; i < 5; i++) {
 		if (info->mem[i].internal_addr)
 			iounmap(info->mem[i].internal_addr);
 	}
 	pci_release_regions(dev);
 out_disable:
 	pci_disable_device(dev);
 	return -ENODEV;
 }

 static void sercos3_pci_remove(struct pci_dev *dev)
 {
 	struct uio_info *info = pci_get_drvdata(dev);
 	int i;

 	uio_unregister_device(info);
 	pci_release_regions(dev);
 	pci_disable_device(dev);
 	for (i = 0; i < 5; i++) {
 		if (info->mem[i].internal_addr)
 			iounmap(info->mem[i].internal_addr);
 	}
 }

 static struct pci_device_id sercos3_pci_ids[] = {
 	{
 		.vendor =       PCI_VENDOR_ID_PLX,
 		.device =       PCI_DEVICE_ID_PLX_9030,
 		.subvendor =    SERCOS_SUB_VENDOR_ID,
 		.subdevice =    SERCOS_SUB_SYSID_3530,
 	},
 	{
 		.vendor =       PCI_VENDOR_ID_PLX,
 		.device =       PCI_DEVICE_ID_PLX_9030,
 		.subvendor =    SERCOS_SUB_VENDOR_ID,
 		.subdevice =    SERCOS_SUB_SYSID_3535,
 	},
 	{
 		.vendor =       PCI_VENDOR_ID_PLX,
 		.device =       PCI_DEVICE_ID_PLX_9030,
 		.subvendor =    SERCOS_SUB_VENDOR_ID,
 		.subdevice =    SERCOS_SUB_SYSID_3780,
 	},
 	{ 0, }
 };

 static struct pci_driver sercos3_pci_driver = {
 	.name = "sercos3",
 	.id_table = sercos3_pci_ids,
 	.probe = sercos3_pci_probe,
 	.remove = sercos3_pci_remove,
 };

 module_pci_driver(sercos3_pci_driver);
 MODULE_DESCRIPTION("UIO driver for the Automata Sercos III PCI card");
 MODULE_AUTHOR("John Ogness <john.ogness@linutronix.de>");
 MODULE_LICENSE("GPL v2");
	// SPDX-License-Identifier: GPL-2.0
	/* sercos3: UIO driver for the Automata Sercos III PCI card

	Copyright (C) 2008 Linutronix GmbH
	Author: John Ogness <john.ogness@linutronix.de>

	This is a straight-forward UIO driver, where interrupts are disabled
	by the interrupt handler and re-enabled via a write to the UIO device
	by the userspace-part.

	The only part that may seem odd is the use of a logical OR when
	storing and restoring enabled interrupts. This is done because the
	userspace-part could directly modify the Interrupt Enable Register
	at any time. To reduce possible conflicts, the kernel driver uses
	a logical OR to make more controlled changes (rather than blindly
	overwriting previous values).

	Race conditions exist if the userspace-part directly modifies the
	Interrupt Enable Register while in operation. The consequences are
	that certain interrupts would fail to be enabled or disabled. For
	this reason, the userspace-part should only directly modify the
	Interrupt Enable Register at the beginning (to get things going).
	The userspace-part can safely disable interrupts at any time using
	a write to the UIO device.
	*/

	#include <linux/device.h>
	#include <linux/module.h>
	#include <linux/pci.h>
	#include <linux/uio_driver.h>
	#include <linux/io.h>
	#include <linux/slab.h>

	/* ID's for SERCOS III PCI card (PLX 9030) */
	#define SERCOS_SUB_VENDOR_ID 0x1971
	#define SERCOS_SUB_SYSID_3530 0x3530
	#define SERCOS_SUB_SYSID_3535 0x3535
	#define SERCOS_SUB_SYSID_3780 0x3780

	/* Interrupt Enable Register */
	#define IER0_OFFSET 0x08

	/* Interrupt Status Register */
	#define ISR0_OFFSET 0x18

	struct sercos3_priv {
	u32 ier0_cache;
	spinlock_t ier0_cache_lock;
	};

	/* this function assumes ier0_cache_lock is locked! */
	static void sercos3_disable_interrupts(struct uio_info *info,
	struct sercos3_priv *priv)
	{
	void __iomem *ier0 = info->mem[3].internal_addr + IER0_OFFSET;

	/* add enabled interrupts to cache */
	priv->ier0_cache \|= ioread32(ier0);

	/* disable interrupts */
	iowrite32(0, ier0);
	}

	/* this function assumes ier0_cache_lock is locked! */
	static void sercos3_enable_interrupts(struct uio_info *info,
	struct sercos3_priv *priv)
	{
	void __iomem *ier0 = info->mem[3].internal_addr + IER0_OFFSET;

	/* restore previously enabled interrupts */
	iowrite32(ioread32(ier0) \| priv->ier0_cache, ier0);
	priv->ier0_cache = 0;
	}

	static irqreturn_t sercos3_handler(int irq, struct uio_info *info)
	{
	struct sercos3_priv *priv = info->priv;
	void __iomem *isr0 = info->mem[3].internal_addr + ISR0_OFFSET;
	void __iomem *ier0 = info->mem[3].internal_addr + IER0_OFFSET;

	if (!(ioread32(isr0) & ioread32(ier0)))
	return IRQ_NONE;

	spin_lock(&priv->ier0_cache_lock);
	sercos3_disable_interrupts(info, priv);
	spin_unlock(&priv->ier0_cache_lock);

	return IRQ_HANDLED;
	}

	static int sercos3_irqcontrol(struct uio_info *info, s32 irq_on)
	{
	struct sercos3_priv *priv = info->priv;

	spin_lock_irq(&priv->ier0_cache_lock);
	if (irq_on)
	sercos3_enable_interrupts(info, priv);
	else
	sercos3_disable_interrupts(info, priv);
	spin_unlock_irq(&priv->ier0_cache_lock);

	return 0;
	}

	static int sercos3_setup_iomem(struct pci_dev dev, struct uio_info info,
	int n, int pci_bar)
	{
	info->mem[n].addr = pci_resource_start(dev, pci_bar);
	if (!info->mem[n].addr)
	return -1;
	info->mem[n].internal_addr = ioremap(pci_resource_start(dev, pci_bar),
	pci_resource_len(dev, pci_bar));
	if (!info->mem[n].internal_addr)
	return -1;
	info->mem[n].size = pci_resource_len(dev, pci_bar);
	info->mem[n].memtype = UIO_MEM_PHYS;
	return 0;
	}

	static int sercos3_pci_probe(struct pci_dev *dev,
	const struct pci_device_id *id)
	{
	struct uio_info *info;
	struct sercos3_priv *priv;
	int i;

	info = devm_kzalloc(&dev->dev, sizeof(struct uio_info), GFP_KERNEL);
	if (!info)
	return -ENOMEM;

	priv = devm_kzalloc(&dev->dev, sizeof(struct sercos3_priv), GFP_KERNEL);
	if (!priv)
	return -ENOMEM;

	if (pci_enable_device(dev))
	return -ENODEV;

	if (pci_request_regions(dev, "sercos3"))
	goto out_disable;

	/* we only need PCI BAR's 0, 2, 3, 4, 5 */
	if (sercos3_setup_iomem(dev, info, 0, 0))
	goto out_unmap;
	if (sercos3_setup_iomem(dev, info, 1, 2))
	goto out_unmap;
	if (sercos3_setup_iomem(dev, info, 2, 3))
	goto out_unmap;
	if (sercos3_setup_iomem(dev, info, 3, 4))
	goto out_unmap;
	if (sercos3_setup_iomem(dev, info, 4, 5))
	goto out_unmap;

	spin_lock_init(&priv->ier0_cache_lock);
	info->priv = priv;
	info->name = "Sercos_III_PCI";
	info->version = "0.0.1";
	info->irq = dev->irq;
	info->irq_flags = IRQF_SHARED;
	info->handler = sercos3_handler;
	info->irqcontrol = sercos3_irqcontrol;

	pci_set_drvdata(dev, info);

	if (uio_register_device(&dev->dev, info))
	goto out_unmap;

	return 0;

	out_unmap:
	for (i = 0; i < 5; i++) {
	if (info->mem[i].internal_addr)
	iounmap(info->mem[i].internal_addr);
	}
	pci_release_regions(dev);
	out_disable:
	pci_disable_device(dev);
	return -ENODEV;
	}

	static void sercos3_pci_remove(struct pci_dev *dev)
	{
	struct uio_info *info = pci_get_drvdata(dev);
	int i;

	uio_unregister_device(info);
	pci_release_regions(dev);
	pci_disable_device(dev);
	for (i = 0; i < 5; i++) {
	if (info->mem[i].internal_addr)
	iounmap(info->mem[i].internal_addr);
	}
	}

	static struct pci_device_id sercos3_pci_ids[] = {
	{
	.vendor = PCI_VENDOR_ID_PLX,
	.device = PCI_DEVICE_ID_PLX_9030,
	.subvendor = SERCOS_SUB_VENDOR_ID,
	.subdevice = SERCOS_SUB_SYSID_3530,
	},
	{
	.vendor = PCI_VENDOR_ID_PLX,
	.device = PCI_DEVICE_ID_PLX_9030,
	.subvendor = SERCOS_SUB_VENDOR_ID,
	.subdevice = SERCOS_SUB_SYSID_3535,
	},
	{
	.vendor = PCI_VENDOR_ID_PLX,
	.device = PCI_DEVICE_ID_PLX_9030,
	.subvendor = SERCOS_SUB_VENDOR_ID,
	.subdevice = SERCOS_SUB_SYSID_3780,
	},
	{ 0, }
	};

	static struct pci_driver sercos3_pci_driver = {
	.name = "sercos3",
	.id_table = sercos3_pci_ids,
	.probe = sercos3_pci_probe,
	.remove = sercos3_pci_remove,
	};

	module_pci_driver(sercos3_pci_driver);
	MODULE_DESCRIPTION("UIO driver for the Automata Sercos III PCI card");
	MODULE_AUTHOR("John Ogness <john.ogness@linutronix.de>");
	MODULE_LICENSE("GPL v2");