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c767db0a MD |
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> | |
af76756e | 23 | #include <linux/pm_runtime.h> |
c767db0a MD |
24 | |
25 | #define DRIVER_NAME "uio_pdrv_genirq" | |
26 | ||
27 | struct uio_pdrv_genirq_platdata { | |
28 | struct uio_info *uioinfo; | |
29 | spinlock_t lock; | |
30 | unsigned long flags; | |
af76756e | 31 | struct platform_device *pdev; |
c767db0a MD |
32 | }; |
33 | ||
af76756e MD |
34 | static int uio_pdrv_genirq_open(struct uio_info *info, struct inode *inode) |
35 | { | |
36 | struct uio_pdrv_genirq_platdata *priv = info->priv; | |
37 | ||
38 | /* Wait until the Runtime PM code has woken up the device */ | |
39 | pm_runtime_get_sync(&priv->pdev->dev); | |
40 | return 0; | |
41 | } | |
42 | ||
43 | static int uio_pdrv_genirq_release(struct uio_info *info, struct inode *inode) | |
44 | { | |
45 | struct uio_pdrv_genirq_platdata *priv = info->priv; | |
46 | ||
47 | /* Tell the Runtime PM code that the device has become idle */ | |
48 | pm_runtime_put_sync(&priv->pdev->dev); | |
49 | return 0; | |
50 | } | |
51 | ||
c767db0a MD |
52 | static irqreturn_t uio_pdrv_genirq_handler(int irq, struct uio_info *dev_info) |
53 | { | |
54 | struct uio_pdrv_genirq_platdata *priv = dev_info->priv; | |
55 | ||
56 | /* Just disable the interrupt in the interrupt controller, and | |
57 | * remember the state so we can allow user space to enable it later. | |
58 | */ | |
59 | ||
60 | if (!test_and_set_bit(0, &priv->flags)) | |
61 | disable_irq_nosync(irq); | |
62 | ||
63 | return IRQ_HANDLED; | |
64 | } | |
65 | ||
66 | static int uio_pdrv_genirq_irqcontrol(struct uio_info *dev_info, s32 irq_on) | |
67 | { | |
68 | struct uio_pdrv_genirq_platdata *priv = dev_info->priv; | |
69 | unsigned long flags; | |
70 | ||
71 | /* Allow user space to enable and disable the interrupt | |
72 | * in the interrupt controller, but keep track of the | |
73 | * state to prevent per-irq depth damage. | |
74 | * | |
75 | * Serialize this operation to support multiple tasks. | |
76 | */ | |
77 | ||
78 | spin_lock_irqsave(&priv->lock, flags); | |
79 | if (irq_on) { | |
80 | if (test_and_clear_bit(0, &priv->flags)) | |
81 | enable_irq(dev_info->irq); | |
82 | } else { | |
83 | if (!test_and_set_bit(0, &priv->flags)) | |
84 | disable_irq(dev_info->irq); | |
85 | } | |
86 | spin_unlock_irqrestore(&priv->lock, flags); | |
87 | ||
88 | return 0; | |
89 | } | |
90 | ||
91 | static int uio_pdrv_genirq_probe(struct platform_device *pdev) | |
92 | { | |
93 | struct uio_info *uioinfo = pdev->dev.platform_data; | |
94 | struct uio_pdrv_genirq_platdata *priv; | |
95 | struct uio_mem *uiomem; | |
96 | int ret = -EINVAL; | |
97 | int i; | |
98 | ||
99 | if (!uioinfo || !uioinfo->name || !uioinfo->version) { | |
100 | dev_err(&pdev->dev, "missing platform_data\n"); | |
101 | goto bad0; | |
102 | } | |
103 | ||
e543ae89 MF |
104 | if (uioinfo->handler || uioinfo->irqcontrol || |
105 | uioinfo->irq_flags & IRQF_SHARED) { | |
c767db0a MD |
106 | dev_err(&pdev->dev, "interrupt configuration error\n"); |
107 | goto bad0; | |
108 | } | |
109 | ||
110 | priv = kzalloc(sizeof(*priv), GFP_KERNEL); | |
111 | if (!priv) { | |
112 | ret = -ENOMEM; | |
113 | dev_err(&pdev->dev, "unable to kmalloc\n"); | |
114 | goto bad0; | |
115 | } | |
116 | ||
117 | priv->uioinfo = uioinfo; | |
118 | spin_lock_init(&priv->lock); | |
119 | priv->flags = 0; /* interrupt is enabled to begin with */ | |
af76756e | 120 | priv->pdev = pdev; |
c767db0a MD |
121 | |
122 | uiomem = &uioinfo->mem[0]; | |
123 | ||
124 | for (i = 0; i < pdev->num_resources; ++i) { | |
125 | struct resource *r = &pdev->resource[i]; | |
126 | ||
127 | if (r->flags != IORESOURCE_MEM) | |
128 | continue; | |
129 | ||
130 | if (uiomem >= &uioinfo->mem[MAX_UIO_MAPS]) { | |
131 | dev_warn(&pdev->dev, "device has more than " | |
132 | __stringify(MAX_UIO_MAPS) | |
133 | " I/O memory resources.\n"); | |
134 | break; | |
135 | } | |
136 | ||
137 | uiomem->memtype = UIO_MEM_PHYS; | |
138 | uiomem->addr = r->start; | |
139 | uiomem->size = r->end - r->start + 1; | |
140 | ++uiomem; | |
141 | } | |
142 | ||
143 | while (uiomem < &uioinfo->mem[MAX_UIO_MAPS]) { | |
144 | uiomem->size = 0; | |
145 | ++uiomem; | |
146 | } | |
147 | ||
148 | /* This driver requires no hardware specific kernel code to handle | |
149 | * interrupts. Instead, the interrupt handler simply disables the | |
150 | * interrupt in the interrupt controller. User space is responsible | |
151 | * for performing hardware specific acknowledge and re-enabling of | |
152 | * the interrupt in the interrupt controller. | |
153 | * | |
154 | * Interrupt sharing is not supported. | |
155 | */ | |
156 | ||
e543ae89 | 157 | uioinfo->irq_flags |= IRQF_DISABLED; |
c767db0a MD |
158 | uioinfo->handler = uio_pdrv_genirq_handler; |
159 | uioinfo->irqcontrol = uio_pdrv_genirq_irqcontrol; | |
af76756e MD |
160 | uioinfo->open = uio_pdrv_genirq_open; |
161 | uioinfo->release = uio_pdrv_genirq_release; | |
c767db0a MD |
162 | uioinfo->priv = priv; |
163 | ||
af76756e MD |
164 | /* Enable Runtime PM for this device: |
165 | * The device starts in suspended state to allow the hardware to be | |
166 | * turned off by default. The Runtime PM bus code should power on the | |
167 | * hardware and enable clocks at open(). | |
168 | */ | |
169 | pm_runtime_enable(&pdev->dev); | |
170 | ||
c767db0a MD |
171 | ret = uio_register_device(&pdev->dev, priv->uioinfo); |
172 | if (ret) { | |
173 | dev_err(&pdev->dev, "unable to register uio device\n"); | |
174 | goto bad1; | |
175 | } | |
176 | ||
177 | platform_set_drvdata(pdev, priv); | |
178 | return 0; | |
179 | bad1: | |
180 | kfree(priv); | |
181 | bad0: | |
182 | return ret; | |
183 | } | |
184 | ||
185 | static int uio_pdrv_genirq_remove(struct platform_device *pdev) | |
186 | { | |
187 | struct uio_pdrv_genirq_platdata *priv = platform_get_drvdata(pdev); | |
188 | ||
189 | uio_unregister_device(priv->uioinfo); | |
af76756e | 190 | pm_runtime_disable(&pdev->dev); |
c767db0a MD |
191 | kfree(priv); |
192 | return 0; | |
193 | } | |
194 | ||
af76756e MD |
195 | static int uio_pdrv_genirq_runtime_nop(struct device *dev) |
196 | { | |
197 | /* Runtime PM callback shared between ->runtime_suspend() | |
198 | * and ->runtime_resume(). Simply returns success. | |
199 | * | |
200 | * In this driver pm_runtime_get_sync() and pm_runtime_put_sync() | |
201 | * are used at open() and release() time. This allows the | |
202 | * Runtime PM code to turn off power to the device while the | |
203 | * device is unused, ie before open() and after release(). | |
204 | * | |
205 | * This Runtime PM callback does not need to save or restore | |
206 | * any registers since user space is responsbile for hardware | |
207 | * register reinitialization after open(). | |
208 | */ | |
209 | return 0; | |
210 | } | |
211 | ||
212 | static struct dev_pm_ops uio_pdrv_genirq_dev_pm_ops = { | |
213 | .runtime_suspend = uio_pdrv_genirq_runtime_nop, | |
214 | .runtime_resume = uio_pdrv_genirq_runtime_nop, | |
215 | }; | |
216 | ||
c767db0a MD |
217 | static struct platform_driver uio_pdrv_genirq = { |
218 | .probe = uio_pdrv_genirq_probe, | |
219 | .remove = uio_pdrv_genirq_remove, | |
220 | .driver = { | |
221 | .name = DRIVER_NAME, | |
222 | .owner = THIS_MODULE, | |
af76756e | 223 | .pm = &uio_pdrv_genirq_dev_pm_ops, |
c767db0a MD |
224 | }, |
225 | }; | |
226 | ||
227 | static int __init uio_pdrv_genirq_init(void) | |
228 | { | |
229 | return platform_driver_register(&uio_pdrv_genirq); | |
230 | } | |
231 | ||
232 | static void __exit uio_pdrv_genirq_exit(void) | |
233 | { | |
234 | platform_driver_unregister(&uio_pdrv_genirq); | |
235 | } | |
236 | ||
237 | module_init(uio_pdrv_genirq_init); | |
238 | module_exit(uio_pdrv_genirq_exit); | |
239 | ||
240 | MODULE_AUTHOR("Magnus Damm"); | |
241 | MODULE_DESCRIPTION("Userspace I/O platform driver with generic IRQ handling"); | |
242 | MODULE_LICENSE("GPL v2"); | |
243 | MODULE_ALIAS("platform:" DRIVER_NAME); |