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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 | #include <linux/slab.h> |
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 | |
119 | static int __devinit sercos3_pci_probe(struct pci_dev *dev, |
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; |
157 | info->irq_flags = IRQF_DISABLED | IRQF_SHARED; |
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); |
191 | pci_set_drvdata(dev, NULL); |
192 | for (i = 0; i < 5; i++) { |
193 | if (info->mem[i].internal_addr) |
194 | iounmap(info->mem[i].internal_addr); |
195 | } |
196 | kfree(info->priv); |
197 | kfree(info); |
198 | } |
199 | |
200 | static struct pci_device_id sercos3_pci_ids[] __devinitdata = { |
201 | { |
202 | .vendor = PCI_VENDOR_ID_PLX, |
203 | .device = PCI_DEVICE_ID_PLX_9030, |
204 | .subvendor = SERCOS_SUB_VENDOR_ID, |
205 | .subdevice = SERCOS_SUB_SYSID_3530, |
206 | }, |
207 | { |
208 | .vendor = PCI_VENDOR_ID_PLX, |
209 | .device = PCI_DEVICE_ID_PLX_9030, |
210 | .subvendor = SERCOS_SUB_VENDOR_ID, |
211 | .subdevice = SERCOS_SUB_SYSID_3535, |
212 | }, |
213 | { |
214 | .vendor = PCI_VENDOR_ID_PLX, |
215 | .device = PCI_DEVICE_ID_PLX_9030, |
216 | .subvendor = SERCOS_SUB_VENDOR_ID, |
217 | .subdevice = SERCOS_SUB_SYSID_3780, |
218 | }, |
219 | { 0, } |
220 | }; |
221 | |
222 | static struct pci_driver sercos3_pci_driver = { |
223 | .name = "sercos3", |
224 | .id_table = sercos3_pci_ids, |
225 | .probe = sercos3_pci_probe, |
226 | .remove = sercos3_pci_remove, |
227 | }; |
228 | |
229 | static int __init sercos3_init_module(void) |
230 | { |
231 | return pci_register_driver(&sercos3_pci_driver); |
232 | } |
233 | |
234 | static void __exit sercos3_exit_module(void) |
235 | { |
236 | pci_unregister_driver(&sercos3_pci_driver); |
237 | } |
238 | |
239 | module_init(sercos3_init_module); |
240 | module_exit(sercos3_exit_module); |
241 | |
242 | MODULE_DESCRIPTION("UIO driver for the Automata Sercos III PCI card"); |
243 | MODULE_AUTHOR("John Ogness <john.ogness@linutronix.de>"); |
244 | MODULE_LICENSE("GPL v2"); |
245 |
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