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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
Vitalii Demianets34cb2752013-06-20 16:36:00 +030040/* Bits in uio_pdrv_genirq_platdata.flags */
41enum {
42 UIO_IRQ_DISABLED = 0,
43};
44
Magnus Dammaf76756e2009-08-14 10:49:38 +000045static int uio_pdrv_genirq_open(struct uio_info *info, struct inode *inode)
46{
47 struct uio_pdrv_genirq_platdata *priv = info->priv;
48
49 /* Wait until the Runtime PM code has woken up the device */
50 pm_runtime_get_sync(&priv->pdev->dev);
51 return 0;
52}
53
54static int uio_pdrv_genirq_release(struct uio_info *info, struct inode *inode)
55{
56 struct uio_pdrv_genirq_platdata *priv = info->priv;
57
58 /* Tell the Runtime PM code that the device has become idle */
59 pm_runtime_put_sync(&priv->pdev->dev);
60 return 0;
61}
62
Magnus Dammc767db02008-07-11 18:55:27 +090063static irqreturn_t uio_pdrv_genirq_handler(int irq, struct uio_info *dev_info)
64{
65 struct uio_pdrv_genirq_platdata *priv = dev_info->priv;
66
67 /* Just disable the interrupt in the interrupt controller, and
68 * remember the state so we can allow user space to enable it later.
69 */
70
Vitalii Demianets34cb2752013-06-20 16:36:00 +030071 spin_lock(&priv->lock);
72 if (!__test_and_set_bit(UIO_IRQ_DISABLED, &priv->flags))
Magnus Dammc767db02008-07-11 18:55:27 +090073 disable_irq_nosync(irq);
Vitalii Demianets34cb2752013-06-20 16:36:00 +030074 spin_unlock(&priv->lock);
Magnus Dammc767db02008-07-11 18:55:27 +090075
76 return IRQ_HANDLED;
77}
78
79static int uio_pdrv_genirq_irqcontrol(struct uio_info *dev_info, s32 irq_on)
80{
81 struct uio_pdrv_genirq_platdata *priv = dev_info->priv;
82 unsigned long flags;
83
84 /* Allow user space to enable and disable the interrupt
85 * in the interrupt controller, but keep track of the
86 * state to prevent per-irq depth damage.
87 *
Vitalii Demianets34cb2752013-06-20 16:36:00 +030088 * Serialize this operation to support multiple tasks and concurrency
89 * with irq handler on SMP systems.
Magnus Dammc767db02008-07-11 18:55:27 +090090 */
91
92 spin_lock_irqsave(&priv->lock, flags);
93 if (irq_on) {
Vitalii Demianets34cb2752013-06-20 16:36:00 +030094 if (__test_and_clear_bit(UIO_IRQ_DISABLED, &priv->flags))
Magnus Dammc767db02008-07-11 18:55:27 +090095 enable_irq(dev_info->irq);
96 } else {
Vitalii Demianets34cb2752013-06-20 16:36:00 +030097 if (!__test_and_set_bit(UIO_IRQ_DISABLED, &priv->flags))
98 disable_irq_nosync(dev_info->irq);
Magnus Dammc767db02008-07-11 18:55:27 +090099 }
100 spin_unlock_irqrestore(&priv->lock, flags);
101
102 return 0;
103}
104
105static int uio_pdrv_genirq_probe(struct platform_device *pdev)
106{
Jingoo Han08cb2e22013-08-30 13:13:11 +0900107 struct uio_info *uioinfo = dev_get_platdata(&pdev->dev);
Magnus Dammc767db02008-07-11 18:55:27 +0900108 struct uio_pdrv_genirq_platdata *priv;
109 struct uio_mem *uiomem;
110 int ret = -EINVAL;
111 int i;
112
Damian Hobson-Garciad5185c42012-11-16 14:46:12 +0900113 if (pdev->dev.of_node) {
Hans J. Koch27760f82011-07-07 23:11:38 +0200114 /* alloc uioinfo for one device */
Michal Simeke6789cd2013-09-12 07:39:59 +0200115 uioinfo = devm_kzalloc(&pdev->dev, sizeof(*uioinfo),
116 GFP_KERNEL);
Hans J. Koch27760f82011-07-07 23:11:38 +0200117 if (!uioinfo) {
Hans J. Koch27760f82011-07-07 23:11:38 +0200118 dev_err(&pdev->dev, "unable to kmalloc\n");
Michal Simeke6789cd2013-09-12 07:39:59 +0200119 return -ENOMEM;
Hans J. Koch27760f82011-07-07 23:11:38 +0200120 }
121 uioinfo->name = pdev->dev.of_node->name;
122 uioinfo->version = "devicetree";
Hans J. Koch27760f82011-07-07 23:11:38 +0200123 /* Multiple IRQs are not supported */
Hans J. Koch27760f82011-07-07 23:11:38 +0200124 }
125
Magnus Dammc767db02008-07-11 18:55:27 +0900126 if (!uioinfo || !uioinfo->name || !uioinfo->version) {
127 dev_err(&pdev->dev, "missing platform_data\n");
Michal Simeke6789cd2013-09-12 07:39:59 +0200128 return ret;
Magnus Dammc767db02008-07-11 18:55:27 +0900129 }
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");
Michal Simeke6789cd2013-09-12 07:39:59 +0200134 return ret;
Magnus Dammc767db02008-07-11 18:55:27 +0900135 }
136
Michal Simeke6789cd2013-09-12 07:39:59 +0200137 priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
Magnus Dammc767db02008-07-11 18:55:27 +0900138 if (!priv) {
Magnus Dammc767db02008-07-11 18:55:27 +0900139 dev_err(&pdev->dev, "unable to kmalloc\n");
Michal Simeke6789cd2013-09-12 07:39:59 +0200140 return -ENOMEM;
Magnus Dammc767db02008-07-11 18:55:27 +0900141 }
142
143 priv->uioinfo = uioinfo;
144 spin_lock_init(&priv->lock);
145 priv->flags = 0; /* interrupt is enabled to begin with */
Magnus Dammaf76756e2009-08-14 10:49:38 +0000146 priv->pdev = pdev;
Magnus Dammc767db02008-07-11 18:55:27 +0900147
Benedikt Spranger94ca6292012-05-14 18:48:17 +0200148 if (!uioinfo->irq) {
149 ret = platform_get_irq(pdev, 0);
Benedikt Spranger94ca6292012-05-14 18:48:17 +0200150 uioinfo->irq = ret;
Pavel Macheke3a3c3a2013-06-18 22:34:53 +0200151 if (ret == -ENXIO && pdev->dev.of_node)
152 uioinfo->irq = UIO_IRQ_NONE;
153 else if (ret < 0) {
154 dev_err(&pdev->dev, "failed to get IRQ\n");
Michal Simeke6789cd2013-09-12 07:39:59 +0200155 return ret;
Pavel Macheke3a3c3a2013-06-18 22:34:53 +0200156 }
Benedikt Spranger94ca6292012-05-14 18:48:17 +0200157 }
Pavel Macheke3a3c3a2013-06-18 22:34:53 +0200158
Magnus Dammc767db02008-07-11 18:55:27 +0900159 uiomem = &uioinfo->mem[0];
160
161 for (i = 0; i < pdev->num_resources; ++i) {
162 struct resource *r = &pdev->resource[i];
163
164 if (r->flags != IORESOURCE_MEM)
165 continue;
166
167 if (uiomem >= &uioinfo->mem[MAX_UIO_MAPS]) {
168 dev_warn(&pdev->dev, "device has more than "
169 __stringify(MAX_UIO_MAPS)
170 " I/O memory resources.\n");
171 break;
172 }
173
174 uiomem->memtype = UIO_MEM_PHYS;
175 uiomem->addr = r->start;
Joe Perches28f65c112011-06-09 09:13:32 -0700176 uiomem->size = resource_size(r);
Manuel Trautecd43c02012-11-09 07:06:40 +0100177 uiomem->name = r->name;
Magnus Dammc767db02008-07-11 18:55:27 +0900178 ++uiomem;
179 }
180
181 while (uiomem < &uioinfo->mem[MAX_UIO_MAPS]) {
182 uiomem->size = 0;
183 ++uiomem;
184 }
185
186 /* This driver requires no hardware specific kernel code to handle
187 * interrupts. Instead, the interrupt handler simply disables the
188 * interrupt in the interrupt controller. User space is responsible
189 * for performing hardware specific acknowledge and re-enabling of
190 * the interrupt in the interrupt controller.
191 *
192 * Interrupt sharing is not supported.
193 */
194
Magnus Dammc767db02008-07-11 18:55:27 +0900195 uioinfo->handler = uio_pdrv_genirq_handler;
196 uioinfo->irqcontrol = uio_pdrv_genirq_irqcontrol;
Magnus Dammaf76756e2009-08-14 10:49:38 +0000197 uioinfo->open = uio_pdrv_genirq_open;
198 uioinfo->release = uio_pdrv_genirq_release;
Magnus Dammc767db02008-07-11 18:55:27 +0900199 uioinfo->priv = priv;
200
Magnus Dammaf76756e2009-08-14 10:49:38 +0000201 /* Enable Runtime PM for this device:
202 * The device starts in suspended state to allow the hardware to be
203 * turned off by default. The Runtime PM bus code should power on the
204 * hardware and enable clocks at open().
205 */
206 pm_runtime_enable(&pdev->dev);
207
Magnus Dammc767db02008-07-11 18:55:27 +0900208 ret = uio_register_device(&pdev->dev, priv->uioinfo);
209 if (ret) {
210 dev_err(&pdev->dev, "unable to register uio device\n");
Michal Simeke6789cd2013-09-12 07:39:59 +0200211 pm_runtime_disable(&pdev->dev);
212 return ret;
Magnus Dammc767db02008-07-11 18:55:27 +0900213 }
214
215 platform_set_drvdata(pdev, priv);
216 return 0;
Magnus Dammc767db02008-07-11 18:55:27 +0900217}
218
219static int uio_pdrv_genirq_remove(struct platform_device *pdev)
220{
221 struct uio_pdrv_genirq_platdata *priv = platform_get_drvdata(pdev);
222
223 uio_unregister_device(priv->uioinfo);
Magnus Dammaf76756e2009-08-14 10:49:38 +0000224 pm_runtime_disable(&pdev->dev);
Jie Zhou47296b12011-04-06 14:42:40 +0800225
226 priv->uioinfo->handler = NULL;
227 priv->uioinfo->irqcontrol = NULL;
228
Magnus Dammc767db02008-07-11 18:55:27 +0900229 return 0;
230}
231
Magnus Dammaf76756e2009-08-14 10:49:38 +0000232static int uio_pdrv_genirq_runtime_nop(struct device *dev)
233{
234 /* Runtime PM callback shared between ->runtime_suspend()
235 * and ->runtime_resume(). Simply returns success.
236 *
237 * In this driver pm_runtime_get_sync() and pm_runtime_put_sync()
238 * are used at open() and release() time. This allows the
239 * Runtime PM code to turn off power to the device while the
240 * device is unused, ie before open() and after release().
241 *
242 * This Runtime PM callback does not need to save or restore
243 * any registers since user space is responsbile for hardware
244 * register reinitialization after open().
245 */
246 return 0;
247}
248
Alexey Dobriyan47145212009-12-14 18:00:08 -0800249static const struct dev_pm_ops uio_pdrv_genirq_dev_pm_ops = {
Magnus Dammaf76756e2009-08-14 10:49:38 +0000250 .runtime_suspend = uio_pdrv_genirq_runtime_nop,
251 .runtime_resume = uio_pdrv_genirq_runtime_nop,
252};
253
Hans J. Koch27760f82011-07-07 23:11:38 +0200254#ifdef CONFIG_OF
Pavel Machek05c3e0b2013-06-18 22:35:58 +0200255static struct of_device_id uio_of_genirq_match[] = {
256 { /* This is filled with module_parm */ },
257 { /* Sentinel */ },
Hans J. Koch27760f82011-07-07 23:11:38 +0200258};
259MODULE_DEVICE_TABLE(of, uio_of_genirq_match);
Pavel Machek05c3e0b2013-06-18 22:35:58 +0200260module_param_string(of_id, uio_of_genirq_match[0].compatible, 128, 0);
261MODULE_PARM_DESC(of_id, "Openfirmware id of the device to be handled by uio");
Hans J. Koch27760f82011-07-07 23:11:38 +0200262#endif
263
Magnus Dammc767db02008-07-11 18:55:27 +0900264static 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,
Magnus Dammaf76756e2009-08-14 10:49:38 +0000270 .pm = &uio_pdrv_genirq_dev_pm_ops,
Sachin Kamatcee4fbd2013-06-25 09:59:52 +0530271 .of_match_table = of_match_ptr(uio_of_genirq_match),
Magnus Dammc767db02008-07-11 18:55:27 +0900272 },
273};
274
Axel Lin11e31232011-11-26 15:18:55 +0800275module_platform_driver(uio_pdrv_genirq);
Magnus Dammc767db02008-07-11 18:55:27 +0900276
277MODULE_AUTHOR("Magnus Damm");
278MODULE_DESCRIPTION("Userspace I/O platform driver with generic IRQ handling");
279MODULE_LICENSE("GPL v2");
280MODULE_ALIAS("platform:" DRIVER_NAME);