[linux.git] / drivers / uio / uio_sercos3.c

/* sercos3: UIO driver for the Automata Sercos III PCI card

   Copyright (C) 2008 Linutronix GmbH
     Author: John Ogness <[email protected]>

   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 = 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_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);
	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[] = {
	{
		.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 <[email protected]>");
MODULE_LICENSE("GPL v2");
Commit	Line	Data
a6030fcc JO	1	/* sercos3: UIO driver for the Automata Sercos III PCI card
	2
	3	Copyright (C) 2008 Linutronix GmbH
	4	Author: John Ogness <[email protected]>
	5
	6	This is a straight-forward UIO driver, where interrupts are disabled
	7	by the interrupt handler and re-enabled via a write to the UIO device
	8	by the userspace-part.
	9
	10	The only part that may seem odd is the use of a logical OR when
	11	storing and restoring enabled interrupts. This is done because the
	12	userspace-part could directly modify the Interrupt Enable Register
	13	at any time. To reduce possible conflicts, the kernel driver uses
	14	a logical OR to make more controlled changes (rather than blindly
	15	overwriting previous values).
	16
	17	Race conditions exist if the userspace-part directly modifies the
	18	Interrupt Enable Register while in operation. The consequences are
	19	that certain interrupts would fail to be enabled or disabled. For
	20	this reason, the userspace-part should only directly modify the
	21	Interrupt Enable Register at the beginning (to get things going).
	22	The userspace-part can safely disable interrupts at any time using
	23	a write to the UIO device.
	24	*/
	25
	26	#include <linux/device.h>
	27	#include <linux/module.h>
	28	#include <linux/pci.h>
	29	#include <linux/uio_driver.h>
	30	#include <linux/io.h>
5a0e3ad6	31	#include <linux/slab.h>
a6030fcc JO	32
	33	/* ID's for SERCOS III PCI card (PLX 9030) */
	34	#define SERCOS_SUB_VENDOR_ID 0x1971
	35	#define SERCOS_SUB_SYSID_3530 0x3530
	36	#define SERCOS_SUB_SYSID_3535 0x3535
	37	#define SERCOS_SUB_SYSID_3780 0x3780
	38
	39	/* Interrupt Enable Register */
	40	#define IER0_OFFSET 0x08
	41
	42	/* Interrupt Status Register */
	43	#define ISR0_OFFSET 0x18
	44
	45	struct sercos3_priv {
	46	u32 ier0_cache;
	47	spinlock_t ier0_cache_lock;
	48	};
	49
	50	/* this function assumes ier0_cache_lock is locked! */
	51	static void sercos3_disable_interrupts(struct uio_info *info,
	52	struct sercos3_priv *priv)
	53	{
	54	void __iomem *ier0 = info->mem[3].internal_addr + IER0_OFFSET;
	55
	56	/* add enabled interrupts to cache */
	57	priv->ier0_cache \|= ioread32(ier0);
	58
	59	/* disable interrupts */
	60	iowrite32(0, ier0);
	61	}
	62
	63	/* this function assumes ier0_cache_lock is locked! */
	64	static void sercos3_enable_interrupts(struct uio_info *info,
	65	struct sercos3_priv *priv)
	66	{
	67	void __iomem *ier0 = info->mem[3].internal_addr + IER0_OFFSET;
	68
	69	/* restore previously enabled interrupts */
	70	iowrite32(ioread32(ier0) \| priv->ier0_cache, ier0);
	71	priv->ier0_cache = 0;
	72	}
	73
	74	static irqreturn_t sercos3_handler(int irq, struct uio_info *info)
	75	{
	76	struct sercos3_priv *priv = info->priv;
	77	void __iomem *isr0 = info->mem[3].internal_addr + ISR0_OFFSET;
	78	void __iomem *ier0 = info->mem[3].internal_addr + IER0_OFFSET;
	79
	80	if (!(ioread32(isr0) & ioread32(ier0)))
	81	return IRQ_NONE;
	82
	83	spin_lock(&priv->ier0_cache_lock);
	84	sercos3_disable_interrupts(info, priv);
	85	spin_unlock(&priv->ier0_cache_lock);
	86
	87	return IRQ_HANDLED;
	88	}
	89
	90	static int sercos3_irqcontrol(struct uio_info *info, s32 irq_on)
	91	{
	92	struct sercos3_priv *priv = info->priv;
	93
	94	spin_lock_irq(&priv->ier0_cache_lock);
	95	if (irq_on)
96	sercos3_enable_interrupts(info, priv);
97	else
98	sercos3_disable_interrupts(info, priv);
99	spin_unlock_irq(&priv->ier0_cache_lock);
100
101	return 0;
102	}
103
104	static int sercos3_setup_iomem(struct pci_dev dev, struct uio_info info,
105	int n, int pci_bar)
106	{
107	info->mem[n].addr = pci_resource_start(dev, pci_bar);
108	if (!info->mem[n].addr)
109	return -1;
110	info->mem[n].internal_addr = ioremap(pci_resource_start(dev, pci_bar),
111	pci_resource_len(dev, pci_bar));
112	if (!info->mem[n].internal_addr)
113	return -1;
114	info->mem[n].size = pci_resource_len(dev, pci_bar);
115	info->mem[n].memtype = UIO_MEM_PHYS;
116	return 0;
117	}
118
b17b75bb	119	static int sercos3_pci_probe(struct pci_dev *dev,
a6030fcc JO	120	const struct pci_device_id *id)
	121	{
	122	struct uio_info *info;
	123	struct sercos3_priv *priv;
	124	int i;
	125
	126	info = kzalloc(sizeof(struct uio_info), GFP_KERNEL);
	127	if (!info)
	128	return -ENOMEM;
	129
	130	priv = kzalloc(sizeof(struct sercos3_priv), GFP_KERNEL);
	131	if (!priv)
	132	goto out_free;
	133
	134	if (pci_enable_device(dev))
	135	goto out_free_priv;
	136
	137	if (pci_request_regions(dev, "sercos3"))
	138	goto out_disable;
	139
	140	/* we only need PCI BAR's 0, 2, 3, 4, 5 */
	141	if (sercos3_setup_iomem(dev, info, 0, 0))
	142	goto out_unmap;
	143	if (sercos3_setup_iomem(dev, info, 1, 2))
	144	goto out_unmap;
	145	if (sercos3_setup_iomem(dev, info, 2, 3))
	146	goto out_unmap;
	147	if (sercos3_setup_iomem(dev, info, 3, 4))
	148	goto out_unmap;
	149	if (sercos3_setup_iomem(dev, info, 4, 5))
	150	goto out_unmap;
	151
	152	spin_lock_init(&priv->ier0_cache_lock);
	153	info->priv = priv;
	154	info->name = "Sercos_III_PCI";
	155	info->version = "0.0.1";
	156	info->irq = dev->irq;
62c86779	157	info->irq_flags = IRQF_SHARED;
a6030fcc JO	158	info->handler = sercos3_handler;
	159	info->irqcontrol = sercos3_irqcontrol;
	160
	161	pci_set_drvdata(dev, info);
	162
	163	if (uio_register_device(&dev->dev, info))
	164	goto out_unmap;
	165
	166	return 0;
	167
	168	out_unmap:
	169	for (i = 0; i < 5; i++) {
	170	if (info->mem[i].internal_addr)
	171	iounmap(info->mem[i].internal_addr);
	172	}
	173	pci_release_regions(dev);
	174	out_disable:
	175	pci_disable_device(dev);
	176	out_free_priv:
	177	kfree(priv);
	178	out_free:
	179	kfree(info);
	180	return -ENODEV;
	181	}
	182
	183	static void sercos3_pci_remove(struct pci_dev *dev)
	184	{
	185	struct uio_info *info = pci_get_drvdata(dev);
	186	int i;
	187
	188	uio_unregister_device(info);
	189	pci_release_regions(dev);
	190	pci_disable_device(dev);
a6030fcc JO	191	for (i = 0; i < 5; i++) {
	192	if (info->mem[i].internal_addr)
	193	iounmap(info->mem[i].internal_addr);
	194	}
	195	kfree(info->priv);
	196	kfree(info);
	197	}
	198
d46f7438	199	static struct pci_device_id sercos3_pci_ids[] = {
a6030fcc JO	200	{
	201	.vendor = PCI_VENDOR_ID_PLX,
	202	.device = PCI_DEVICE_ID_PLX_9030,
	203	.subvendor = SERCOS_SUB_VENDOR_ID,
	204	.subdevice = SERCOS_SUB_SYSID_3530,
	205	},
	206	{
	207	.vendor = PCI_VENDOR_ID_PLX,
	208	.device = PCI_DEVICE_ID_PLX_9030,
	209	.subvendor = SERCOS_SUB_VENDOR_ID,
	210	.subdevice = SERCOS_SUB_SYSID_3535,
	211	},
	212	{
	213	.vendor = PCI_VENDOR_ID_PLX,
	214	.device = PCI_DEVICE_ID_PLX_9030,
	215	.subvendor = SERCOS_SUB_VENDOR_ID,
	216	.subdevice = SERCOS_SUB_SYSID_3780,
	217	},
	218	{ 0, }
	219	};
	220
	221	static struct pci_driver sercos3_pci_driver = {
	222	.name = "sercos3",
	223	.id_table = sercos3_pci_ids,
	224	.probe = sercos3_pci_probe,
	225	.remove = sercos3_pci_remove,
	226	};
	227
8bcaec4e	228	module_pci_driver(sercos3_pci_driver);
a6030fcc JO	229	MODULE_DESCRIPTION("UIO driver for the Automata Sercos III PCI card");
	230	MODULE_AUTHOR("John Ogness <[email protected]>");
	231	MODULE_LICENSE("GPL v2");