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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> | |
2949ead4 | 21 | #include <linux/module.h> |
c767db0a MD |
22 | #include <linux/interrupt.h> |
23 | #include <linux/stringify.h> | |
af76756e | 24 | #include <linux/pm_runtime.h> |
5a0e3ad6 | 25 | #include <linux/slab.h> |
c767db0a | 26 | |
27760f86 HK |
27 | #include <linux/of.h> |
28 | #include <linux/of_platform.h> | |
29 | #include <linux/of_address.h> | |
30 | ||
c767db0a MD |
31 | #define DRIVER_NAME "uio_pdrv_genirq" |
32 | ||
33 | struct uio_pdrv_genirq_platdata { | |
34 | struct uio_info *uioinfo; | |
35 | spinlock_t lock; | |
36 | unsigned long flags; | |
af76756e | 37 | struct platform_device *pdev; |
c767db0a MD |
38 | }; |
39 | ||
af76756e MD |
40 | static int uio_pdrv_genirq_open(struct uio_info *info, struct inode *inode) |
41 | { | |
42 | struct uio_pdrv_genirq_platdata *priv = info->priv; | |
43 | ||
44 | /* Wait until the Runtime PM code has woken up the device */ | |
45 | pm_runtime_get_sync(&priv->pdev->dev); | |
46 | return 0; | |
47 | } | |
48 | ||
49 | static int uio_pdrv_genirq_release(struct uio_info *info, struct inode *inode) | |
50 | { | |
51 | struct uio_pdrv_genirq_platdata *priv = info->priv; | |
52 | ||
53 | /* Tell the Runtime PM code that the device has become idle */ | |
54 | pm_runtime_put_sync(&priv->pdev->dev); | |
55 | return 0; | |
56 | } | |
57 | ||
c767db0a MD |
58 | static irqreturn_t uio_pdrv_genirq_handler(int irq, struct uio_info *dev_info) |
59 | { | |
60 | struct uio_pdrv_genirq_platdata *priv = dev_info->priv; | |
61 | ||
62 | /* Just disable the interrupt in the interrupt controller, and | |
63 | * remember the state so we can allow user space to enable it later. | |
64 | */ | |
65 | ||
66 | if (!test_and_set_bit(0, &priv->flags)) | |
67 | disable_irq_nosync(irq); | |
68 | ||
69 | return IRQ_HANDLED; | |
70 | } | |
71 | ||
72 | static int uio_pdrv_genirq_irqcontrol(struct uio_info *dev_info, s32 irq_on) | |
73 | { | |
74 | struct uio_pdrv_genirq_platdata *priv = dev_info->priv; | |
75 | unsigned long flags; | |
76 | ||
77 | /* Allow user space to enable and disable the interrupt | |
78 | * in the interrupt controller, but keep track of the | |
79 | * state to prevent per-irq depth damage. | |
80 | * | |
81 | * Serialize this operation to support multiple tasks. | |
82 | */ | |
83 | ||
84 | spin_lock_irqsave(&priv->lock, flags); | |
85 | if (irq_on) { | |
86 | if (test_and_clear_bit(0, &priv->flags)) | |
87 | enable_irq(dev_info->irq); | |
88 | } else { | |
89 | if (!test_and_set_bit(0, &priv->flags)) | |
90 | disable_irq(dev_info->irq); | |
91 | } | |
92 | spin_unlock_irqrestore(&priv->lock, flags); | |
93 | ||
94 | return 0; | |
95 | } | |
96 | ||
97 | static int uio_pdrv_genirq_probe(struct platform_device *pdev) | |
98 | { | |
99 | struct uio_info *uioinfo = pdev->dev.platform_data; | |
100 | struct uio_pdrv_genirq_platdata *priv; | |
101 | struct uio_mem *uiomem; | |
102 | int ret = -EINVAL; | |
103 | int i; | |
104 | ||
27760f86 HK |
105 | if (!uioinfo) { |
106 | int irq; | |
107 | ||
108 | /* alloc uioinfo for one device */ | |
109 | uioinfo = kzalloc(sizeof(*uioinfo), GFP_KERNEL); | |
110 | if (!uioinfo) { | |
111 | ret = -ENOMEM; | |
112 | dev_err(&pdev->dev, "unable to kmalloc\n"); | |
113 | goto bad2; | |
114 | } | |
115 | uioinfo->name = pdev->dev.of_node->name; | |
116 | uioinfo->version = "devicetree"; | |
117 | ||
118 | /* Multiple IRQs are not supported */ | |
119 | irq = platform_get_irq(pdev, 0); | |
120 | if (irq == -ENXIO) | |
121 | uioinfo->irq = UIO_IRQ_NONE; | |
122 | else | |
123 | uioinfo->irq = irq; | |
124 | } | |
125 | ||
c767db0a MD |
126 | if (!uioinfo || !uioinfo->name || !uioinfo->version) { |
127 | dev_err(&pdev->dev, "missing platform_data\n"); | |
128 | goto bad0; | |
129 | } | |
130 | ||
e543ae89 MF |
131 | if (uioinfo->handler || uioinfo->irqcontrol || |
132 | uioinfo->irq_flags & IRQF_SHARED) { | |
c767db0a MD |
133 | dev_err(&pdev->dev, "interrupt configuration error\n"); |
134 | goto bad0; | |
135 | } | |
136 | ||
137 | priv = kzalloc(sizeof(*priv), GFP_KERNEL); | |
138 | if (!priv) { | |
139 | ret = -ENOMEM; | |
140 | dev_err(&pdev->dev, "unable to kmalloc\n"); | |
141 | goto bad0; | |
142 | } | |
143 | ||
144 | priv->uioinfo = uioinfo; | |
145 | spin_lock_init(&priv->lock); | |
146 | priv->flags = 0; /* interrupt is enabled to begin with */ | |
af76756e | 147 | priv->pdev = pdev; |
c767db0a MD |
148 | |
149 | uiomem = &uioinfo->mem[0]; | |
150 | ||
151 | for (i = 0; i < pdev->num_resources; ++i) { | |
152 | struct resource *r = &pdev->resource[i]; | |
153 | ||
154 | if (r->flags != IORESOURCE_MEM) | |
155 | continue; | |
156 | ||
157 | if (uiomem >= &uioinfo->mem[MAX_UIO_MAPS]) { | |
158 | dev_warn(&pdev->dev, "device has more than " | |
159 | __stringify(MAX_UIO_MAPS) | |
160 | " I/O memory resources.\n"); | |
161 | break; | |
162 | } | |
163 | ||
164 | uiomem->memtype = UIO_MEM_PHYS; | |
165 | uiomem->addr = r->start; | |
28f65c11 | 166 | uiomem->size = resource_size(r); |
c767db0a MD |
167 | ++uiomem; |
168 | } | |
169 | ||
170 | while (uiomem < &uioinfo->mem[MAX_UIO_MAPS]) { | |
171 | uiomem->size = 0; | |
172 | ++uiomem; | |
173 | } | |
174 | ||
175 | /* This driver requires no hardware specific kernel code to handle | |
176 | * interrupts. Instead, the interrupt handler simply disables the | |
177 | * interrupt in the interrupt controller. User space is responsible | |
178 | * for performing hardware specific acknowledge and re-enabling of | |
179 | * the interrupt in the interrupt controller. | |
180 | * | |
181 | * Interrupt sharing is not supported. | |
182 | */ | |
183 | ||
c767db0a MD |
184 | uioinfo->handler = uio_pdrv_genirq_handler; |
185 | uioinfo->irqcontrol = uio_pdrv_genirq_irqcontrol; | |
af76756e MD |
186 | uioinfo->open = uio_pdrv_genirq_open; |
187 | uioinfo->release = uio_pdrv_genirq_release; | |
c767db0a MD |
188 | uioinfo->priv = priv; |
189 | ||
af76756e MD |
190 | /* Enable Runtime PM for this device: |
191 | * The device starts in suspended state to allow the hardware to be | |
192 | * turned off by default. The Runtime PM bus code should power on the | |
193 | * hardware and enable clocks at open(). | |
194 | */ | |
195 | pm_runtime_enable(&pdev->dev); | |
196 | ||
c767db0a MD |
197 | ret = uio_register_device(&pdev->dev, priv->uioinfo); |
198 | if (ret) { | |
199 | dev_err(&pdev->dev, "unable to register uio device\n"); | |
200 | goto bad1; | |
201 | } | |
202 | ||
203 | platform_set_drvdata(pdev, priv); | |
204 | return 0; | |
205 | bad1: | |
206 | kfree(priv); | |
68fb2e49 | 207 | pm_runtime_disable(&pdev->dev); |
c767db0a | 208 | bad0: |
27760f86 HK |
209 | /* kfree uioinfo for OF */ |
210 | if (pdev->dev.of_node) | |
211 | kfree(uioinfo); | |
212 | bad2: | |
c767db0a MD |
213 | return ret; |
214 | } | |
215 | ||
216 | static int uio_pdrv_genirq_remove(struct platform_device *pdev) | |
217 | { | |
218 | struct uio_pdrv_genirq_platdata *priv = platform_get_drvdata(pdev); | |
219 | ||
220 | uio_unregister_device(priv->uioinfo); | |
af76756e | 221 | pm_runtime_disable(&pdev->dev); |
47296b19 JZ |
222 | |
223 | priv->uioinfo->handler = NULL; | |
224 | priv->uioinfo->irqcontrol = NULL; | |
225 | ||
27760f86 HK |
226 | /* kfree uioinfo for OF */ |
227 | if (pdev->dev.of_node) | |
228 | kfree(priv->uioinfo); | |
229 | ||
c767db0a MD |
230 | kfree(priv); |
231 | return 0; | |
232 | } | |
233 | ||
af76756e MD |
234 | static int uio_pdrv_genirq_runtime_nop(struct device *dev) |
235 | { | |
236 | /* Runtime PM callback shared between ->runtime_suspend() | |
237 | * and ->runtime_resume(). Simply returns success. | |
238 | * | |
239 | * In this driver pm_runtime_get_sync() and pm_runtime_put_sync() | |
240 | * are used at open() and release() time. This allows the | |
241 | * Runtime PM code to turn off power to the device while the | |
242 | * device is unused, ie before open() and after release(). | |
243 | * | |
244 | * This Runtime PM callback does not need to save or restore | |
245 | * any registers since user space is responsbile for hardware | |
246 | * register reinitialization after open(). | |
247 | */ | |
248 | return 0; | |
249 | } | |
250 | ||
47145210 | 251 | static const struct dev_pm_ops uio_pdrv_genirq_dev_pm_ops = { |
af76756e MD |
252 | .runtime_suspend = uio_pdrv_genirq_runtime_nop, |
253 | .runtime_resume = uio_pdrv_genirq_runtime_nop, | |
254 | }; | |
255 | ||
27760f86 | 256 | #ifdef CONFIG_OF |
9245acd2 | 257 | static const struct of_device_id uio_of_genirq_match[] = { |
27760f86 HK |
258 | { /* empty for now */ }, |
259 | }; | |
260 | MODULE_DEVICE_TABLE(of, uio_of_genirq_match); | |
261 | #else | |
262 | # define uio_of_genirq_match NULL | |
263 | #endif | |
264 | ||
c767db0a MD |
265 | static struct platform_driver uio_pdrv_genirq = { |
266 | .probe = uio_pdrv_genirq_probe, | |
267 | .remove = uio_pdrv_genirq_remove, | |
268 | .driver = { | |
269 | .name = DRIVER_NAME, | |
270 | .owner = THIS_MODULE, | |
af76756e | 271 | .pm = &uio_pdrv_genirq_dev_pm_ops, |
27760f86 | 272 | .of_match_table = uio_of_genirq_match, |
c767db0a MD |
273 | }, |
274 | }; | |
275 | ||
276 | static int __init uio_pdrv_genirq_init(void) | |
277 | { | |
278 | return platform_driver_register(&uio_pdrv_genirq); | |
279 | } | |
280 | ||
281 | static void __exit uio_pdrv_genirq_exit(void) | |
282 | { | |
283 | platform_driver_unregister(&uio_pdrv_genirq); | |
284 | } | |
285 | ||
286 | module_init(uio_pdrv_genirq_init); | |
287 | module_exit(uio_pdrv_genirq_exit); | |
288 | ||
289 | MODULE_AUTHOR("Magnus Damm"); | |
290 | MODULE_DESCRIPTION("Userspace I/O platform driver with generic IRQ handling"); | |
291 | MODULE_LICENSE("GPL v2"); | |
292 | MODULE_ALIAS("platform:" DRIVER_NAME); |