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Commit a6030fcc authored by John Ogness's avatar John Ogness Committed by Greg Kroah-Hartman
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UIO: add automata sercos3 pci card support 



Here is a new version of the patch to support the Automata Sercos III
PCI card driver. I now check that the IRQ is enabled before accepting
the interrupt.

I still use a logical OR to store the enabled interrupts and I've
added a second use of a logical OR when restoring the enabled
interrupts. I added an explanation of why I do this in comments at the
top of the source file.

Since I use a logical OR, I also removed the extra checks if the
Interrupt Enable Register and ier0_cache are 0.

Signed-off-by: default avatarJohn Ogness <john.ogness@linutronix.de>
Signed-off-by: default avatarHans J. Koch <hjk@linutronix.de>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent a6fcc3a1

drivers/uio/Kconfig

+13 −0
Original line number Diff line number Diff line
@@ -58,4 +58,17 @@ config UIO_SMX 


	  If you compile this as a module, it will be called uio_smx.



config UIO_SERCOS3

	tristate "Automata Sercos III PCI card driver"

	default n

	help

	  Userspace I/O interface for the Sercos III PCI card from

	  Automata GmbH. The userspace part of this driver will be

	  available for download from the Automata GmbH web site.



	  Automata GmbH:        http://www.automataweb.com

	  Sercos III interface: http://www.sercos.com



	  If you compile this as a module, it will be called uio_sercos3.



endif

drivers/uio/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -3,3 +3,4 @@ obj-$(CONFIG_UIO_CIF) += uio_cif.o 
obj-$(CONFIG_UIO_PDRV)	+= uio_pdrv.o

obj-$(CONFIG_UIO_PDRV_GENIRQ)	+= uio_pdrv_genirq.o

obj-$(CONFIG_UIO_SMX)	+= uio_smx.o

obj-$(CONFIG_UIO_SERCOS3)	+= uio_sercos3.o

drivers/uio/uio_sercos3.c

0 → 100644
+243 −0
Original line number Diff line number Diff line 
/* 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>



/* 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 __devinit sercos3_pci_probe(struct pci_dev *dev,

				       const struct pci_device_id *id)

{

	struct uio_info *info;

	struct sercos3_priv *priv;

	int i;



	info = kzalloc(sizeof(struct uio_info), GFP_KERNEL);

	if (!info)

		return -ENOMEM;



	priv = kzalloc(sizeof(struct sercos3_priv), GFP_KERNEL);

	if (!priv)

		goto out_free;



	if (pci_enable_device(dev))

		goto out_free_priv;



	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_DISABLED | 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);

out_free_priv:

	kfree(priv);

out_free:

	kfree(info);

	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);

	pci_set_drvdata(dev, NULL);

	for (i = 0; i < 5; i++) {

		if (info->mem[i].internal_addr)

			iounmap(info->mem[i].internal_addr);

	}

	kfree(info->priv);

	kfree(info);

}



static struct pci_device_id sercos3_pci_ids[] __devinitdata = {

	{

		.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,

};



static int __init sercos3_init_module(void)

{

	return pci_register_driver(&sercos3_pci_driver);

}



static void __exit sercos3_exit_module(void)

{

	pci_unregister_driver(&sercos3_pci_driver);

}



module_init(sercos3_init_module);

module_exit(sercos3_exit_module);



MODULE_DESCRIPTION("UIO driver for the Automata Sercos III PCI card");

MODULE_AUTHOR("John Ogness <john.ogness@linutronix.de>");

MODULE_LICENSE("GPL v2");