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Magnus Dammc767db02008-07-11 18:55:27 +09001/*
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>
Paul Gortmaker2949ead2011-07-17 16:38:40 -040021#include <linux/module.h>
Magnus Dammc767db02008-07-11 18:55:27 +090022#include <linux/interrupt.h>
23#include <linux/stringify.h>
Magnus Dammaf76756e2009-08-14 10:49:38 +000024#include <linux/pm_runtime.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090025#include <linux/slab.h>
Magnus Dammc767db02008-07-11 18:55:27 +090026
Hans J. Koch27760f82011-07-07 23:11:38 +020027#include <linux/of.h>
28#include <linux/of_platform.h>
29#include <linux/of_address.h>
30
Magnus Dammc767db02008-07-11 18:55:27 +090031#define DRIVER_NAME "uio_pdrv_genirq"
32
33struct uio_pdrv_genirq_platdata {
34 struct uio_info *uioinfo;
35 spinlock_t lock;
36 unsigned long flags;
Magnus Dammaf76756e2009-08-14 10:49:38 +000037 struct platform_device *pdev;
Magnus Dammc767db02008-07-11 18:55:27 +090038};
39
Magnus Dammaf76756e2009-08-14 10:49:38 +000040static 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
49static 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
Magnus Dammc767db02008-07-11 18:55:27 +090058static 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
72static 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
97static 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
Hans J. Koch27760f82011-07-07 23:11:38 +0200105 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
Magnus Dammc767db02008-07-11 18:55:27 +0900126 if (!uioinfo || !uioinfo->name || !uioinfo->version) {
127 dev_err(&pdev->dev, "missing platform_data\n");
128 goto bad0;
129 }
130
Mike Frysingere543ae82008-10-29 18:35:52 -0400131 if (uioinfo->handler || uioinfo->irqcontrol ||
132 uioinfo->irq_flags & IRQF_SHARED) {
Magnus Dammc767db02008-07-11 18:55:27 +0900133 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 */
Magnus Dammaf76756e2009-08-14 10:49:38 +0000147 priv->pdev = pdev;
Magnus Dammc767db02008-07-11 18:55:27 +0900148
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;
Joe Perches28f65c12011-06-09 09:13:32 -0700166 uiomem->size = resource_size(r);
Magnus Dammc767db02008-07-11 18:55:27 +0900167 ++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
Magnus Dammc767db02008-07-11 18:55:27 +0900184 uioinfo->handler = uio_pdrv_genirq_handler;
185 uioinfo->irqcontrol = uio_pdrv_genirq_irqcontrol;
Magnus Dammaf76756e2009-08-14 10:49:38 +0000186 uioinfo->open = uio_pdrv_genirq_open;
187 uioinfo->release = uio_pdrv_genirq_release;
Magnus Dammc767db02008-07-11 18:55:27 +0900188 uioinfo->priv = priv;
189
Magnus Dammaf76756e2009-08-14 10:49:38 +0000190 /* 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
Magnus Dammc767db02008-07-11 18:55:27 +0900197 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);
Kuninori Morimoto68fb2e42009-11-09 02:42:47 +0000207 pm_runtime_disable(&pdev->dev);
Magnus Dammc767db02008-07-11 18:55:27 +0900208 bad0:
Hans J. Koch27760f82011-07-07 23:11:38 +0200209 /* kfree uioinfo for OF */
210 if (pdev->dev.of_node)
211 kfree(uioinfo);
212 bad2:
Magnus Dammc767db02008-07-11 18:55:27 +0900213 return ret;
214}
215
216static 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);
Magnus Dammaf76756e2009-08-14 10:49:38 +0000221 pm_runtime_disable(&pdev->dev);
Jie Zhou47296b12011-04-06 14:42:40 +0800222
223 priv->uioinfo->handler = NULL;
224 priv->uioinfo->irqcontrol = NULL;
225
Hans J. Koch27760f82011-07-07 23:11:38 +0200226 /* kfree uioinfo for OF */
227 if (pdev->dev.of_node)
228 kfree(priv->uioinfo);
229
Magnus Dammc767db02008-07-11 18:55:27 +0900230 kfree(priv);
231 return 0;
232}
233
Magnus Dammaf76756e2009-08-14 10:49:38 +0000234static 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
Alexey Dobriyan47145212009-12-14 18:00:08 -0800251static const struct dev_pm_ops uio_pdrv_genirq_dev_pm_ops = {
Magnus Dammaf76756e2009-08-14 10:49:38 +0000252 .runtime_suspend = uio_pdrv_genirq_runtime_nop,
253 .runtime_resume = uio_pdrv_genirq_runtime_nop,
254};
255
Hans J. Koch27760f82011-07-07 23:11:38 +0200256#ifdef CONFIG_OF
Wanlong Gao9245acd2011-08-20 12:12:07 +0800257static const struct of_device_id uio_of_genirq_match[] = {
Hans J. Koch27760f82011-07-07 23:11:38 +0200258 { /* empty for now */ },
259};
260MODULE_DEVICE_TABLE(of, uio_of_genirq_match);
261#else
262# define uio_of_genirq_match NULL
263#endif
264
Magnus Dammc767db02008-07-11 18:55:27 +0900265static 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,
Magnus Dammaf76756e2009-08-14 10:49:38 +0000271 .pm = &uio_pdrv_genirq_dev_pm_ops,
Hans J. Koch27760f82011-07-07 23:11:38 +0200272 .of_match_table = uio_of_genirq_match,
Magnus Dammc767db02008-07-11 18:55:27 +0900273 },
274};
275
Axel Lin11e31232011-11-26 15:18:55 +0800276module_platform_driver(uio_pdrv_genirq);
Magnus Dammc767db02008-07-11 18:55:27 +0900277
278MODULE_AUTHOR("Magnus Damm");
279MODULE_DESCRIPTION("Userspace I/O platform driver with generic IRQ handling");
280MODULE_LICENSE("GPL v2");
281MODULE_ALIAS("platform:" DRIVER_NAME);