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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 | 148 | |
94ca629e BS |
149 | if (!uioinfo->irq) { |
150 | ret = platform_get_irq(pdev, 0); | |
151 | if (ret < 0) { | |
152 | dev_err(&pdev->dev, "failed to get IRQ\n"); | |
153 | goto bad0; | |
154 | } | |
155 | uioinfo->irq = ret; | |
156 | } | |
c767db0a MD |
157 | uiomem = &uioinfo->mem[0]; |
158 | ||
159 | for (i = 0; i < pdev->num_resources; ++i) { | |
160 | struct resource *r = &pdev->resource[i]; | |
161 | ||
162 | if (r->flags != IORESOURCE_MEM) | |
163 | continue; | |
164 | ||
165 | if (uiomem >= &uioinfo->mem[MAX_UIO_MAPS]) { | |
166 | dev_warn(&pdev->dev, "device has more than " | |
167 | __stringify(MAX_UIO_MAPS) | |
168 | " I/O memory resources.\n"); | |
169 | break; | |
170 | } | |
171 | ||
172 | uiomem->memtype = UIO_MEM_PHYS; | |
173 | uiomem->addr = r->start; | |
28f65c11 | 174 | uiomem->size = resource_size(r); |
c767db0a MD |
175 | ++uiomem; |
176 | } | |
177 | ||
178 | while (uiomem < &uioinfo->mem[MAX_UIO_MAPS]) { | |
179 | uiomem->size = 0; | |
180 | ++uiomem; | |
181 | } | |
182 | ||
183 | /* This driver requires no hardware specific kernel code to handle | |
184 | * interrupts. Instead, the interrupt handler simply disables the | |
185 | * interrupt in the interrupt controller. User space is responsible | |
186 | * for performing hardware specific acknowledge and re-enabling of | |
187 | * the interrupt in the interrupt controller. | |
188 | * | |
189 | * Interrupt sharing is not supported. | |
190 | */ | |
191 | ||
c767db0a MD |
192 | uioinfo->handler = uio_pdrv_genirq_handler; |
193 | uioinfo->irqcontrol = uio_pdrv_genirq_irqcontrol; | |
af76756e MD |
194 | uioinfo->open = uio_pdrv_genirq_open; |
195 | uioinfo->release = uio_pdrv_genirq_release; | |
c767db0a MD |
196 | uioinfo->priv = priv; |
197 | ||
af76756e MD |
198 | /* Enable Runtime PM for this device: |
199 | * The device starts in suspended state to allow the hardware to be | |
200 | * turned off by default. The Runtime PM bus code should power on the | |
201 | * hardware and enable clocks at open(). | |
202 | */ | |
203 | pm_runtime_enable(&pdev->dev); | |
204 | ||
c767db0a MD |
205 | ret = uio_register_device(&pdev->dev, priv->uioinfo); |
206 | if (ret) { | |
207 | dev_err(&pdev->dev, "unable to register uio device\n"); | |
208 | goto bad1; | |
209 | } | |
210 | ||
211 | platform_set_drvdata(pdev, priv); | |
212 | return 0; | |
213 | bad1: | |
214 | kfree(priv); | |
68fb2e49 | 215 | pm_runtime_disable(&pdev->dev); |
c767db0a | 216 | bad0: |
27760f86 HK |
217 | /* kfree uioinfo for OF */ |
218 | if (pdev->dev.of_node) | |
219 | kfree(uioinfo); | |
220 | bad2: | |
c767db0a MD |
221 | return ret; |
222 | } | |
223 | ||
224 | static int uio_pdrv_genirq_remove(struct platform_device *pdev) | |
225 | { | |
226 | struct uio_pdrv_genirq_platdata *priv = platform_get_drvdata(pdev); | |
227 | ||
228 | uio_unregister_device(priv->uioinfo); | |
af76756e | 229 | pm_runtime_disable(&pdev->dev); |
47296b19 JZ |
230 | |
231 | priv->uioinfo->handler = NULL; | |
232 | priv->uioinfo->irqcontrol = NULL; | |
233 | ||
27760f86 HK |
234 | /* kfree uioinfo for OF */ |
235 | if (pdev->dev.of_node) | |
236 | kfree(priv->uioinfo); | |
237 | ||
c767db0a MD |
238 | kfree(priv); |
239 | return 0; | |
240 | } | |
241 | ||
af76756e MD |
242 | static int uio_pdrv_genirq_runtime_nop(struct device *dev) |
243 | { | |
244 | /* Runtime PM callback shared between ->runtime_suspend() | |
245 | * and ->runtime_resume(). Simply returns success. | |
246 | * | |
247 | * In this driver pm_runtime_get_sync() and pm_runtime_put_sync() | |
248 | * are used at open() and release() time. This allows the | |
249 | * Runtime PM code to turn off power to the device while the | |
250 | * device is unused, ie before open() and after release(). | |
251 | * | |
252 | * This Runtime PM callback does not need to save or restore | |
253 | * any registers since user space is responsbile for hardware | |
254 | * register reinitialization after open(). | |
255 | */ | |
256 | return 0; | |
257 | } | |
258 | ||
47145210 | 259 | static const struct dev_pm_ops uio_pdrv_genirq_dev_pm_ops = { |
af76756e MD |
260 | .runtime_suspend = uio_pdrv_genirq_runtime_nop, |
261 | .runtime_resume = uio_pdrv_genirq_runtime_nop, | |
262 | }; | |
263 | ||
27760f86 | 264 | #ifdef CONFIG_OF |
9245acd2 | 265 | static const struct of_device_id uio_of_genirq_match[] = { |
27760f86 HK |
266 | { /* empty for now */ }, |
267 | }; | |
268 | MODULE_DEVICE_TABLE(of, uio_of_genirq_match); | |
269 | #else | |
270 | # define uio_of_genirq_match NULL | |
271 | #endif | |
272 | ||
c767db0a MD |
273 | static struct platform_driver uio_pdrv_genirq = { |
274 | .probe = uio_pdrv_genirq_probe, | |
275 | .remove = uio_pdrv_genirq_remove, | |
276 | .driver = { | |
277 | .name = DRIVER_NAME, | |
278 | .owner = THIS_MODULE, | |
af76756e | 279 | .pm = &uio_pdrv_genirq_dev_pm_ops, |
27760f86 | 280 | .of_match_table = uio_of_genirq_match, |
c767db0a MD |
281 | }, |
282 | }; | |
283 | ||
11e3123d | 284 | module_platform_driver(uio_pdrv_genirq); |
c767db0a MD |
285 | |
286 | MODULE_AUTHOR("Magnus Damm"); | |
287 | MODULE_DESCRIPTION("Userspace I/O platform driver with generic IRQ handling"); | |
288 | MODULE_LICENSE("GPL v2"); | |
289 | MODULE_ALIAS("platform:" DRIVER_NAME); |