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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> |
5a0e3ad6 | 24 | #include <linux/slab.h> |
c767db0a | 25 | |
27760f86 HK |
26 | #include <linux/of.h> |
27 | #include <linux/of_platform.h> | |
28 | #include <linux/of_address.h> | |
29 | ||
c767db0a MD |
30 | #define DRIVER_NAME "uio_pdrv_genirq" |
31 | ||
32 | struct uio_pdrv_genirq_platdata { | |
33 | struct uio_info *uioinfo; | |
34 | spinlock_t lock; | |
35 | unsigned long flags; | |
af76756e | 36 | struct platform_device *pdev; |
c767db0a MD |
37 | }; |
38 | ||
af76756e MD |
39 | static int uio_pdrv_genirq_open(struct uio_info *info, struct inode *inode) |
40 | { | |
41 | struct uio_pdrv_genirq_platdata *priv = info->priv; | |
42 | ||
43 | /* Wait until the Runtime PM code has woken up the device */ | |
44 | pm_runtime_get_sync(&priv->pdev->dev); | |
45 | return 0; | |
46 | } | |
47 | ||
48 | static int uio_pdrv_genirq_release(struct uio_info *info, struct inode *inode) | |
49 | { | |
50 | struct uio_pdrv_genirq_platdata *priv = info->priv; | |
51 | ||
52 | /* Tell the Runtime PM code that the device has become idle */ | |
53 | pm_runtime_put_sync(&priv->pdev->dev); | |
54 | return 0; | |
55 | } | |
56 | ||
c767db0a MD |
57 | static irqreturn_t uio_pdrv_genirq_handler(int irq, struct uio_info *dev_info) |
58 | { | |
59 | struct uio_pdrv_genirq_platdata *priv = dev_info->priv; | |
60 | ||
61 | /* Just disable the interrupt in the interrupt controller, and | |
62 | * remember the state so we can allow user space to enable it later. | |
63 | */ | |
64 | ||
65 | if (!test_and_set_bit(0, &priv->flags)) | |
66 | disable_irq_nosync(irq); | |
67 | ||
68 | return IRQ_HANDLED; | |
69 | } | |
70 | ||
71 | static int uio_pdrv_genirq_irqcontrol(struct uio_info *dev_info, s32 irq_on) | |
72 | { | |
73 | struct uio_pdrv_genirq_platdata *priv = dev_info->priv; | |
74 | unsigned long flags; | |
75 | ||
76 | /* Allow user space to enable and disable the interrupt | |
77 | * in the interrupt controller, but keep track of the | |
78 | * state to prevent per-irq depth damage. | |
79 | * | |
80 | * Serialize this operation to support multiple tasks. | |
81 | */ | |
82 | ||
83 | spin_lock_irqsave(&priv->lock, flags); | |
84 | if (irq_on) { | |
85 | if (test_and_clear_bit(0, &priv->flags)) | |
86 | enable_irq(dev_info->irq); | |
87 | } else { | |
88 | if (!test_and_set_bit(0, &priv->flags)) | |
89 | disable_irq(dev_info->irq); | |
90 | } | |
91 | spin_unlock_irqrestore(&priv->lock, flags); | |
92 | ||
93 | return 0; | |
94 | } | |
95 | ||
96 | static int uio_pdrv_genirq_probe(struct platform_device *pdev) | |
97 | { | |
98 | struct uio_info *uioinfo = pdev->dev.platform_data; | |
99 | struct uio_pdrv_genirq_platdata *priv; | |
100 | struct uio_mem *uiomem; | |
101 | int ret = -EINVAL; | |
102 | int i; | |
103 | ||
27760f86 HK |
104 | if (!uioinfo) { |
105 | int irq; | |
106 | ||
107 | /* alloc uioinfo for one device */ | |
108 | uioinfo = kzalloc(sizeof(*uioinfo), GFP_KERNEL); | |
109 | if (!uioinfo) { | |
110 | ret = -ENOMEM; | |
111 | dev_err(&pdev->dev, "unable to kmalloc\n"); | |
112 | goto bad2; | |
113 | } | |
114 | uioinfo->name = pdev->dev.of_node->name; | |
115 | uioinfo->version = "devicetree"; | |
116 | ||
117 | /* Multiple IRQs are not supported */ | |
118 | irq = platform_get_irq(pdev, 0); | |
119 | if (irq == -ENXIO) | |
120 | uioinfo->irq = UIO_IRQ_NONE; | |
121 | else | |
122 | uioinfo->irq = irq; | |
123 | } | |
124 | ||
c767db0a MD |
125 | if (!uioinfo || !uioinfo->name || !uioinfo->version) { |
126 | dev_err(&pdev->dev, "missing platform_data\n"); | |
127 | goto bad0; | |
128 | } | |
129 | ||
e543ae89 MF |
130 | if (uioinfo->handler || uioinfo->irqcontrol || |
131 | uioinfo->irq_flags & IRQF_SHARED) { | |
c767db0a MD |
132 | dev_err(&pdev->dev, "interrupt configuration error\n"); |
133 | goto bad0; | |
134 | } | |
135 | ||
136 | priv = kzalloc(sizeof(*priv), GFP_KERNEL); | |
137 | if (!priv) { | |
138 | ret = -ENOMEM; | |
139 | dev_err(&pdev->dev, "unable to kmalloc\n"); | |
140 | goto bad0; | |
141 | } | |
142 | ||
143 | priv->uioinfo = uioinfo; | |
144 | spin_lock_init(&priv->lock); | |
145 | priv->flags = 0; /* interrupt is enabled to begin with */ | |
af76756e | 146 | priv->pdev = pdev; |
c767db0a MD |
147 | |
148 | uiomem = &uioinfo->mem[0]; | |
149 | ||
150 | for (i = 0; i < pdev->num_resources; ++i) { | |
151 | struct resource *r = &pdev->resource[i]; | |
152 | ||
153 | if (r->flags != IORESOURCE_MEM) | |
154 | continue; | |
155 | ||
156 | if (uiomem >= &uioinfo->mem[MAX_UIO_MAPS]) { | |
157 | dev_warn(&pdev->dev, "device has more than " | |
158 | __stringify(MAX_UIO_MAPS) | |
159 | " I/O memory resources.\n"); | |
160 | break; | |
161 | } | |
162 | ||
163 | uiomem->memtype = UIO_MEM_PHYS; | |
164 | uiomem->addr = r->start; | |
28f65c11 | 165 | uiomem->size = resource_size(r); |
c767db0a MD |
166 | ++uiomem; |
167 | } | |
168 | ||
169 | while (uiomem < &uioinfo->mem[MAX_UIO_MAPS]) { | |
170 | uiomem->size = 0; | |
171 | ++uiomem; | |
172 | } | |
173 | ||
174 | /* This driver requires no hardware specific kernel code to handle | |
175 | * interrupts. Instead, the interrupt handler simply disables the | |
176 | * interrupt in the interrupt controller. User space is responsible | |
177 | * for performing hardware specific acknowledge and re-enabling of | |
178 | * the interrupt in the interrupt controller. | |
179 | * | |
180 | * Interrupt sharing is not supported. | |
181 | */ | |
182 | ||
c767db0a MD |
183 | uioinfo->handler = uio_pdrv_genirq_handler; |
184 | uioinfo->irqcontrol = uio_pdrv_genirq_irqcontrol; | |
af76756e MD |
185 | uioinfo->open = uio_pdrv_genirq_open; |
186 | uioinfo->release = uio_pdrv_genirq_release; | |
c767db0a MD |
187 | uioinfo->priv = priv; |
188 | ||
af76756e MD |
189 | /* Enable Runtime PM for this device: |
190 | * The device starts in suspended state to allow the hardware to be | |
191 | * turned off by default. The Runtime PM bus code should power on the | |
192 | * hardware and enable clocks at open(). | |
193 | */ | |
194 | pm_runtime_enable(&pdev->dev); | |
195 | ||
c767db0a MD |
196 | ret = uio_register_device(&pdev->dev, priv->uioinfo); |
197 | if (ret) { | |
198 | dev_err(&pdev->dev, "unable to register uio device\n"); | |
199 | goto bad1; | |
200 | } | |
201 | ||
202 | platform_set_drvdata(pdev, priv); | |
203 | return 0; | |
204 | bad1: | |
205 | kfree(priv); | |
68fb2e49 | 206 | pm_runtime_disable(&pdev->dev); |
c767db0a | 207 | bad0: |
27760f86 HK |
208 | /* kfree uioinfo for OF */ |
209 | if (pdev->dev.of_node) | |
210 | kfree(uioinfo); | |
211 | bad2: | |
c767db0a MD |
212 | return ret; |
213 | } | |
214 | ||
215 | static int uio_pdrv_genirq_remove(struct platform_device *pdev) | |
216 | { | |
217 | struct uio_pdrv_genirq_platdata *priv = platform_get_drvdata(pdev); | |
218 | ||
219 | uio_unregister_device(priv->uioinfo); | |
af76756e | 220 | pm_runtime_disable(&pdev->dev); |
47296b19 JZ |
221 | |
222 | priv->uioinfo->handler = NULL; | |
223 | priv->uioinfo->irqcontrol = NULL; | |
224 | ||
27760f86 HK |
225 | /* kfree uioinfo for OF */ |
226 | if (pdev->dev.of_node) | |
227 | kfree(priv->uioinfo); | |
228 | ||
c767db0a MD |
229 | kfree(priv); |
230 | return 0; | |
231 | } | |
232 | ||
af76756e MD |
233 | static int uio_pdrv_genirq_runtime_nop(struct device *dev) |
234 | { | |
235 | /* Runtime PM callback shared between ->runtime_suspend() | |
236 | * and ->runtime_resume(). Simply returns success. | |
237 | * | |
238 | * In this driver pm_runtime_get_sync() and pm_runtime_put_sync() | |
239 | * are used at open() and release() time. This allows the | |
240 | * Runtime PM code to turn off power to the device while the | |
241 | * device is unused, ie before open() and after release(). | |
242 | * | |
243 | * This Runtime PM callback does not need to save or restore | |
244 | * any registers since user space is responsbile for hardware | |
245 | * register reinitialization after open(). | |
246 | */ | |
247 | return 0; | |
248 | } | |
249 | ||
47145210 | 250 | static const struct dev_pm_ops uio_pdrv_genirq_dev_pm_ops = { |
af76756e MD |
251 | .runtime_suspend = uio_pdrv_genirq_runtime_nop, |
252 | .runtime_resume = uio_pdrv_genirq_runtime_nop, | |
253 | }; | |
254 | ||
27760f86 | 255 | #ifdef CONFIG_OF |
9245acd2 | 256 | static const struct of_device_id uio_of_genirq_match[] = { |
27760f86 HK |
257 | { /* empty for now */ }, |
258 | }; | |
259 | MODULE_DEVICE_TABLE(of, uio_of_genirq_match); | |
260 | #else | |
261 | # define uio_of_genirq_match NULL | |
262 | #endif | |
263 | ||
c767db0a MD |
264 | static struct platform_driver uio_pdrv_genirq = { |
265 | .probe = uio_pdrv_genirq_probe, | |
266 | .remove = uio_pdrv_genirq_remove, | |
267 | .driver = { | |
268 | .name = DRIVER_NAME, | |
269 | .owner = THIS_MODULE, | |
af76756e | 270 | .pm = &uio_pdrv_genirq_dev_pm_ops, |
27760f86 | 271 | .of_match_table = uio_of_genirq_match, |
c767db0a MD |
272 | }, |
273 | }; | |
274 | ||
275 | static int __init uio_pdrv_genirq_init(void) | |
276 | { | |
277 | return platform_driver_register(&uio_pdrv_genirq); | |
278 | } | |
279 | ||
280 | static void __exit uio_pdrv_genirq_exit(void) | |
281 | { | |
282 | platform_driver_unregister(&uio_pdrv_genirq); | |
283 | } | |
284 | ||
285 | module_init(uio_pdrv_genirq_init); | |
286 | module_exit(uio_pdrv_genirq_exit); | |
287 | ||
288 | MODULE_AUTHOR("Magnus Damm"); | |
289 | MODULE_DESCRIPTION("Userspace I/O platform driver with generic IRQ handling"); | |
290 | MODULE_LICENSE("GPL v2"); | |
291 | MODULE_ALIAS("platform:" DRIVER_NAME); |