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1 | /* |
2 | * drivers/uio/uio_pdrv_genirq.c |
3 | * |
4 | * Userspace I/O platform driver with generic IRQ handling code. |
5 | * |
6 | * Copyright (C) 2008 Magnus Damm |
7 | * |
8 | * Based on uio_pdrv.c by Uwe Kleine-Koenig, |
9 | * Copyright (C) 2008 by Digi International Inc. |
10 | * All rights reserved. |
11 | * |
12 | * This program is free software; you can redistribute it and/or modify it |
13 | * under the terms of the GNU General Public License version 2 as published by |
14 | * the Free Software Foundation. |
15 | */ |
16 | |
17 | #include <linux/platform_device.h> |
18 | #include <linux/uio_driver.h> |
19 | #include <linux/spinlock.h> |
20 | #include <linux/bitops.h> |
21 | #include <linux/interrupt.h> |
22 | #include <linux/stringify.h> |
23 | #include <linux/pm_runtime.h> |
24 | #include <linux/slab.h> |
25 | |
26 | #define DRIVER_NAME "uio_pdrv_genirq" |
27 | |
28 | struct uio_pdrv_genirq_platdata { |
29 | struct uio_info *uioinfo; |
30 | spinlock_t lock; |
31 | unsigned long flags; |
32 | struct platform_device *pdev; |
33 | }; |
34 | |
35 | static int uio_pdrv_genirq_open(struct uio_info *info, struct inode *inode) |
36 | { |
37 | struct uio_pdrv_genirq_platdata *priv = info->priv; |
38 | |
39 | /* Wait until the Runtime PM code has woken up the device */ |
40 | pm_runtime_get_sync(&priv->pdev->dev); |
41 | return 0; |
42 | } |
43 | |
44 | static int uio_pdrv_genirq_release(struct uio_info *info, struct inode *inode) |
45 | { |
46 | struct uio_pdrv_genirq_platdata *priv = info->priv; |
47 | |
48 | /* Tell the Runtime PM code that the device has become idle */ |
49 | pm_runtime_put_sync(&priv->pdev->dev); |
50 | return 0; |
51 | } |
52 | |
53 | static irqreturn_t uio_pdrv_genirq_handler(int irq, struct uio_info *dev_info) |
54 | { |
55 | struct uio_pdrv_genirq_platdata *priv = dev_info->priv; |
56 | |
57 | /* Just disable the interrupt in the interrupt controller, and |
58 | * remember the state so we can allow user space to enable it later. |
59 | */ |
60 | |
61 | if (!test_and_set_bit(0, &priv->flags)) |
62 | disable_irq_nosync(irq); |
63 | |
64 | return IRQ_HANDLED; |
65 | } |
66 | |
67 | static int uio_pdrv_genirq_irqcontrol(struct uio_info *dev_info, s32 irq_on) |
68 | { |
69 | struct uio_pdrv_genirq_platdata *priv = dev_info->priv; |
70 | unsigned long flags; |
71 | |
72 | /* Allow user space to enable and disable the interrupt |
73 | * in the interrupt controller, but keep track of the |
74 | * state to prevent per-irq depth damage. |
75 | * |
76 | * Serialize this operation to support multiple tasks. |
77 | */ |
78 | |
79 | spin_lock_irqsave(&priv->lock, flags); |
80 | if (irq_on) { |
81 | if (test_and_clear_bit(0, &priv->flags)) |
82 | enable_irq(dev_info->irq); |
83 | } else { |
84 | if (!test_and_set_bit(0, &priv->flags)) |
85 | disable_irq(dev_info->irq); |
86 | } |
87 | spin_unlock_irqrestore(&priv->lock, flags); |
88 | |
89 | return 0; |
90 | } |
91 | |
92 | static int uio_pdrv_genirq_probe(struct platform_device *pdev) |
93 | { |
94 | struct uio_info *uioinfo = pdev->dev.platform_data; |
95 | struct uio_pdrv_genirq_platdata *priv; |
96 | struct uio_mem *uiomem; |
97 | int ret = -EINVAL; |
98 | int i; |
99 | |
100 | if (!uioinfo || !uioinfo->name || !uioinfo->version) { |
101 | dev_err(&pdev->dev, "missing platform_data\n"); |
102 | goto bad0; |
103 | } |
104 | |
105 | if (uioinfo->handler || uioinfo->irqcontrol || |
106 | uioinfo->irq_flags & IRQF_SHARED) { |
107 | dev_err(&pdev->dev, "interrupt configuration error\n"); |
108 | goto bad0; |
109 | } |
110 | |
111 | priv = kzalloc(sizeof(*priv), GFP_KERNEL); |
112 | if (!priv) { |
113 | ret = -ENOMEM; |
114 | dev_err(&pdev->dev, "unable to kmalloc\n"); |
115 | goto bad0; |
116 | } |
117 | |
118 | priv->uioinfo = uioinfo; |
119 | spin_lock_init(&priv->lock); |
120 | priv->flags = 0; /* interrupt is enabled to begin with */ |
121 | priv->pdev = pdev; |
122 | |
123 | uiomem = &uioinfo->mem[0]; |
124 | |
125 | for (i = 0; i < pdev->num_resources; ++i) { |
126 | struct resource *r = &pdev->resource[i]; |
127 | |
128 | if (r->flags != IORESOURCE_MEM) |
129 | continue; |
130 | |
131 | if (uiomem >= &uioinfo->mem[MAX_UIO_MAPS]) { |
132 | dev_warn(&pdev->dev, "device has more than " |
133 | __stringify(MAX_UIO_MAPS) |
134 | " I/O memory resources.\n"); |
135 | break; |
136 | } |
137 | |
138 | uiomem->memtype = UIO_MEM_PHYS; |
139 | uiomem->addr = r->start; |
140 | uiomem->size = r->end - r->start + 1; |
141 | ++uiomem; |
142 | } |
143 | |
144 | while (uiomem < &uioinfo->mem[MAX_UIO_MAPS]) { |
145 | uiomem->size = 0; |
146 | ++uiomem; |
147 | } |
148 | |
149 | /* This driver requires no hardware specific kernel code to handle |
150 | * interrupts. Instead, the interrupt handler simply disables the |
151 | * interrupt in the interrupt controller. User space is responsible |
152 | * for performing hardware specific acknowledge and re-enabling of |
153 | * the interrupt in the interrupt controller. |
154 | * |
155 | * Interrupt sharing is not supported. |
156 | */ |
157 | |
158 | uioinfo->irq_flags |= IRQF_DISABLED; |
159 | uioinfo->handler = uio_pdrv_genirq_handler; |
160 | uioinfo->irqcontrol = uio_pdrv_genirq_irqcontrol; |
161 | uioinfo->open = uio_pdrv_genirq_open; |
162 | uioinfo->release = uio_pdrv_genirq_release; |
163 | uioinfo->priv = priv; |
164 | |
165 | /* Enable Runtime PM for this device: |
166 | * The device starts in suspended state to allow the hardware to be |
167 | * turned off by default. The Runtime PM bus code should power on the |
168 | * hardware and enable clocks at open(). |
169 | */ |
170 | pm_runtime_enable(&pdev->dev); |
171 | |
172 | ret = uio_register_device(&pdev->dev, priv->uioinfo); |
173 | if (ret) { |
174 | dev_err(&pdev->dev, "unable to register uio device\n"); |
175 | goto bad1; |
176 | } |
177 | |
178 | platform_set_drvdata(pdev, priv); |
179 | return 0; |
180 | bad1: |
181 | kfree(priv); |
182 | pm_runtime_disable(&pdev->dev); |
183 | bad0: |
184 | return ret; |
185 | } |
186 | |
187 | static int uio_pdrv_genirq_remove(struct platform_device *pdev) |
188 | { |
189 | struct uio_pdrv_genirq_platdata *priv = platform_get_drvdata(pdev); |
190 | |
191 | uio_unregister_device(priv->uioinfo); |
192 | pm_runtime_disable(&pdev->dev); |
193 | kfree(priv); |
194 | return 0; |
195 | } |
196 | |
197 | static int uio_pdrv_genirq_runtime_nop(struct device *dev) |
198 | { |
199 | /* Runtime PM callback shared between ->runtime_suspend() |
200 | * and ->runtime_resume(). Simply returns success. |
201 | * |
202 | * In this driver pm_runtime_get_sync() and pm_runtime_put_sync() |
203 | * are used at open() and release() time. This allows the |
204 | * Runtime PM code to turn off power to the device while the |
205 | * device is unused, ie before open() and after release(). |
206 | * |
207 | * This Runtime PM callback does not need to save or restore |
208 | * any registers since user space is responsbile for hardware |
209 | * register reinitialization after open(). |
210 | */ |
211 | return 0; |
212 | } |
213 | |
214 | static const struct dev_pm_ops uio_pdrv_genirq_dev_pm_ops = { |
215 | .runtime_suspend = uio_pdrv_genirq_runtime_nop, |
216 | .runtime_resume = uio_pdrv_genirq_runtime_nop, |
217 | }; |
218 | |
219 | static struct platform_driver uio_pdrv_genirq = { |
220 | .probe = uio_pdrv_genirq_probe, |
221 | .remove = uio_pdrv_genirq_remove, |
222 | .driver = { |
223 | .name = DRIVER_NAME, |
224 | .owner = THIS_MODULE, |
225 | .pm = &uio_pdrv_genirq_dev_pm_ops, |
226 | }, |
227 | }; |
228 | |
229 | static int __init uio_pdrv_genirq_init(void) |
230 | { |
231 | return platform_driver_register(&uio_pdrv_genirq); |
232 | } |
233 | |
234 | static void __exit uio_pdrv_genirq_exit(void) |
235 | { |
236 | platform_driver_unregister(&uio_pdrv_genirq); |
237 | } |
238 | |
239 | module_init(uio_pdrv_genirq_init); |
240 | module_exit(uio_pdrv_genirq_exit); |
241 | |
242 | MODULE_AUTHOR("Magnus Damm"); |
243 | MODULE_DESCRIPTION("Userspace I/O platform driver with generic IRQ handling"); |
244 | MODULE_LICENSE("GPL v2"); |
245 | MODULE_ALIAS("platform:" DRIVER_NAME); |
246 |
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Tags:
od-2011-09-04
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