[linux-2.6-block.git] / drivers / uio / uio_sercos3.c

/* 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");
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 <john.ogness@linutronix.de>
	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>
	31
	32	/* ID's for SERCOS III PCI card (PLX 9030) */
	33	#define SERCOS_SUB_VENDOR_ID 0x1971
	34	#define SERCOS_SUB_SYSID_3530 0x3530
	35	#define SERCOS_SUB_SYSID_3535 0x3535
	36	#define SERCOS_SUB_SYSID_3780 0x3780
	37
	38	/* Interrupt Enable Register */
	39	#define IER0_OFFSET 0x08
	40
	41	/* Interrupt Status Register */
	42	#define ISR0_OFFSET 0x18
	43
	44	struct sercos3_priv {
	45	u32 ier0_cache;
	46	spinlock_t ier0_cache_lock;
	47	};
	48
	49	/* this function assumes ier0_cache_lock is locked! */
	50	static void sercos3_disable_interrupts(struct uio_info *info,
	51	struct sercos3_priv *priv)
	52	{
	53	void __iomem *ier0 = info->mem[3].internal_addr + IER0_OFFSET;
	54
	55	/* add enabled interrupts to cache */
	56	priv->ier0_cache \|= ioread32(ier0);
	57
	58	/* disable interrupts */
	59	iowrite32(0, ier0);
	60	}
	61
	62	/* this function assumes ier0_cache_lock is locked! */
	63	static void sercos3_enable_interrupts(struct uio_info *info,
	64	struct sercos3_priv *priv)
65	{
66	void __iomem *ier0 = info->mem[3].internal_addr + IER0_OFFSET;
67
68	/* restore previously enabled interrupts */
69	iowrite32(ioread32(ier0) \| priv->ier0_cache, ier0);
70	priv->ier0_cache = 0;
71	}
72
73	static irqreturn_t sercos3_handler(int irq, struct uio_info *info)
74	{
75	struct sercos3_priv *priv = info->priv;
76	void __iomem *isr0 = info->mem[3].internal_addr + ISR0_OFFSET;
77	void __iomem *ier0 = info->mem[3].internal_addr + IER0_OFFSET;
78
79	if (!(ioread32(isr0) & ioread32(ier0)))
80	return IRQ_NONE;
81
82	spin_lock(&priv->ier0_cache_lock);
83	sercos3_disable_interrupts(info, priv);
84	spin_unlock(&priv->ier0_cache_lock);
85
86	return IRQ_HANDLED;
87	}
88
89	static int sercos3_irqcontrol(struct uio_info *info, s32 irq_on)
90	{
91	struct sercos3_priv *priv = info->priv;
92
93	spin_lock_irq(&priv->ier0_cache_lock);
94	if (irq_on)
95	sercos3_enable_interrupts(info, priv);
96	else
97	sercos3_disable_interrupts(info, priv);
98	spin_unlock_irq(&priv->ier0_cache_lock);
99
100	return 0;
101	}
102
103	static int sercos3_setup_iomem(struct pci_dev dev, struct uio_info info,
104	int n, int pci_bar)
105	{
106	info->mem[n].addr = pci_resource_start(dev, pci_bar);
107	if (!info->mem[n].addr)
108	return -1;
109	info->mem[n].internal_addr = ioremap(pci_resource_start(dev, pci_bar),
110	pci_resource_len(dev, pci_bar));
111	if (!info->mem[n].internal_addr)
112	return -1;
113	info->mem[n].size = pci_resource_len(dev, pci_bar);
114	info->mem[n].memtype = UIO_MEM_PHYS;
115	return 0;
116	}
117
118	static int __devinit sercos3_pci_probe(struct pci_dev *dev,
119	const struct pci_device_id *id)
120	{
121	struct uio_info *info;
122	struct sercos3_priv *priv;
123	int i;
124
125	info = kzalloc(sizeof(struct uio_info), GFP_KERNEL);
126	if (!info)
127	return -ENOMEM;
128
129	priv = kzalloc(sizeof(struct sercos3_priv), GFP_KERNEL);
130	if (!priv)
131	goto out_free;
132
133	if (pci_enable_device(dev))
134	goto out_free_priv;
135
136	if (pci_request_regions(dev, "sercos3"))
137	goto out_disable;
138
139	/* we only need PCI BAR's 0, 2, 3, 4, 5 */
140	if (sercos3_setup_iomem(dev, info, 0, 0))
141	goto out_unmap;
142	if (sercos3_setup_iomem(dev, info, 1, 2))
143	goto out_unmap;
144	if (sercos3_setup_iomem(dev, info, 2, 3))
145	goto out_unmap;
146	if (sercos3_setup_iomem(dev, info, 3, 4))
147	goto out_unmap;
148	if (sercos3_setup_iomem(dev, info, 4, 5))
149	goto out_unmap;
150
151	spin_lock_init(&priv->ier0_cache_lock);
152	info->priv = priv;
153	info->name = "Sercos_III_PCI";
154	info->version = "0.0.1";
155	info->irq = dev->irq;
156	info->irq_flags = IRQF_DISABLED \| IRQF_SHARED;
157	info->handler = sercos3_handler;
158	info->irqcontrol = sercos3_irqcontrol;
159
160	pci_set_drvdata(dev, info);
161
162	if (uio_register_device(&dev->dev, info))
163	goto out_unmap;
164
165	return 0;
166
167	out_unmap:
168	for (i = 0; i < 5; i++) {
169	if (info->mem[i].internal_addr)
170	iounmap(info->mem[i].internal_addr);
171	}
172	pci_release_regions(dev);
173	out_disable:
174	pci_disable_device(dev);
175	out_free_priv:
176	kfree(priv);
177	out_free:
178	kfree(info);
179	return -ENODEV;
180	}
181
182	static void sercos3_pci_remove(struct pci_dev *dev)
183	{
184	struct uio_info *info = pci_get_drvdata(dev);
185	int i;
186
187	uio_unregister_device(info);
188	pci_release_regions(dev);
189	pci_disable_device(dev);
190	pci_set_drvdata(dev, NULL);
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
199	static struct pci_device_id sercos3_pci_ids[] __devinitdata = {
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
228	static int __init sercos3_init_module(void)
229	{
230	return pci_register_driver(&sercos3_pci_driver);
231	}
232
233	static void __exit sercos3_exit_module(void)
234	{
235	pci_unregister_driver(&sercos3_pci_driver);
236	}
237
238	module_init(sercos3_init_module);
239	module_exit(sercos3_exit_module);
240
241	MODULE_DESCRIPTION("UIO driver for the Automata Sercos III PCI card");
242	MODULE_AUTHOR("John Ogness <john.ogness@linutronix.de>");
243	MODULE_LICENSE("GPL v2");