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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/module.h>
22#include <linux/interrupt.h>
23#include <linux/stringify.h>
24#include <linux/pm_runtime.h>
25#include <linux/slab.h>
26
27#include <linux/of.h>
28#include <linux/of_platform.h>
29#include <linux/of_address.h>
30
31#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;
37 struct platform_device *pdev;
38};
39
40/* Bits in uio_pdrv_genirq_platdata.flags */
41enum {
42 UIO_IRQ_DISABLED = 0,
43};
44
45static 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
63static 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
71 spin_lock(&priv->lock);
72 if (!__test_and_set_bit(UIO_IRQ_DISABLED, &priv->flags))
73 disable_irq_nosync(irq);
74 spin_unlock(&priv->lock);
75
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 *
88 * Serialize this operation to support multiple tasks and concurrency
89 * with irq handler on SMP systems.
90 */
91
92 spin_lock_irqsave(&priv->lock, flags);
93 if (irq_on) {
94 if (__test_and_clear_bit(UIO_IRQ_DISABLED, &priv->flags))
95 enable_irq(dev_info->irq);
96 } else {
97 if (!__test_and_set_bit(UIO_IRQ_DISABLED, &priv->flags))
98 disable_irq_nosync(dev_info->irq);
99 }
100 spin_unlock_irqrestore(&priv->lock, flags);
101
102 return 0;
103}
104
105static int uio_pdrv_genirq_probe(struct platform_device *pdev)
106{
107 struct uio_info *uioinfo = dev_get_platdata(&pdev->dev);
108 struct uio_pdrv_genirq_platdata *priv;
109 struct uio_mem *uiomem;
110 int ret = -EINVAL;
111 int i;
112
113 if (pdev->dev.of_node) {
114 /* alloc uioinfo for one device */
115 uioinfo = devm_kzalloc(&pdev->dev, sizeof(*uioinfo),
116 GFP_KERNEL);
117 if (!uioinfo) {
118 dev_err(&pdev->dev, "unable to kmalloc\n");
119 return -ENOMEM;
120 }
121 uioinfo->name = pdev->dev.of_node->name;
122 uioinfo->version = "devicetree";
123 /* Multiple IRQs are not supported */
124 }
125
126 if (!uioinfo || !uioinfo->name || !uioinfo->version) {
127 dev_err(&pdev->dev, "missing platform_data\n");
128 return ret;
129 }
130
131 if (uioinfo->handler || uioinfo->irqcontrol ||
132 uioinfo->irq_flags & IRQF_SHARED) {
133 dev_err(&pdev->dev, "interrupt configuration error\n");
134 return ret;
135 }
136
137 priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
138 if (!priv) {
139 dev_err(&pdev->dev, "unable to kmalloc\n");
140 return -ENOMEM;
141 }
142
143 priv->uioinfo = uioinfo;
144 spin_lock_init(&priv->lock);
145 priv->flags = 0; /* interrupt is enabled to begin with */
146 priv->pdev = pdev;
147
148 if (!uioinfo->irq) {
149 ret = platform_get_irq(pdev, 0);
150 uioinfo->irq = ret;
151 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");
155 return ret;
156 }
157 }
158
159 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;
176 uiomem->size = resource_size(r);
177 uiomem->name = r->name;
178 ++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
195 uioinfo->handler = uio_pdrv_genirq_handler;
196 uioinfo->irqcontrol = uio_pdrv_genirq_irqcontrol;
197 uioinfo->open = uio_pdrv_genirq_open;
198 uioinfo->release = uio_pdrv_genirq_release;
199 uioinfo->priv = priv;
200
201 /* 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
208 ret = uio_register_device(&pdev->dev, priv->uioinfo);
209 if (ret) {
210 dev_err(&pdev->dev, "unable to register uio device\n");
211 pm_runtime_disable(&pdev->dev);
212 return ret;
213 }
214
215 platform_set_drvdata(pdev, priv);
216 return 0;
217}
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);
224 pm_runtime_disable(&pdev->dev);
225
226 priv->uioinfo->handler = NULL;
227 priv->uioinfo->irqcontrol = NULL;
228
229 return 0;
230}
231
232static 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
249static const struct dev_pm_ops uio_pdrv_genirq_dev_pm_ops = {
250 .runtime_suspend = uio_pdrv_genirq_runtime_nop,
251 .runtime_resume = uio_pdrv_genirq_runtime_nop,
252};
253
254#ifdef CONFIG_OF
255static struct of_device_id uio_of_genirq_match[] = {
256 { /* This is filled with module_parm */ },
257 { /* Sentinel */ },
258};
259MODULE_DEVICE_TABLE(of, uio_of_genirq_match);
260module_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");
262#endif
263
264static 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 .pm = &uio_pdrv_genirq_dev_pm_ops,
270 .of_match_table = of_match_ptr(uio_of_genirq_match),
271 },
272};
273
274module_platform_driver(uio_pdrv_genirq);
275
276MODULE_AUTHOR("Magnus Damm");
277MODULE_DESCRIPTION("Userspace I/O platform driver with generic IRQ handling");
278MODULE_LICENSE("GPL v2");
279MODULE_ALIAS("platform:" DRIVER_NAME);
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>
23#include <linux/pm_runtime.h>
24#include <linux/slab.h>
25
26#include <linux/of.h>
27#include <linux/of_platform.h>
28#include <linux/of_address.h>
29
30#define DRIVER_NAME "uio_pdrv_genirq"
31
32struct uio_pdrv_genirq_platdata {
33 struct uio_info *uioinfo;
34 spinlock_t lock;
35 unsigned long flags;
36 struct platform_device *pdev;
37};
38
39static 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
48static 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
57static 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
71static 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
96static 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
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
125 if (!uioinfo || !uioinfo->name || !uioinfo->version) {
126 dev_err(&pdev->dev, "missing platform_data\n");
127 goto bad0;
128 }
129
130 if (uioinfo->handler || uioinfo->irqcontrol ||
131 uioinfo->irq_flags & IRQF_SHARED) {
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 */
146 priv->pdev = pdev;
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;
165 uiomem->size = resource_size(r);
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
183 uioinfo->handler = uio_pdrv_genirq_handler;
184 uioinfo->irqcontrol = uio_pdrv_genirq_irqcontrol;
185 uioinfo->open = uio_pdrv_genirq_open;
186 uioinfo->release = uio_pdrv_genirq_release;
187 uioinfo->priv = priv;
188
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
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);
206 pm_runtime_disable(&pdev->dev);
207 bad0:
208 /* kfree uioinfo for OF */
209 if (pdev->dev.of_node)
210 kfree(uioinfo);
211 bad2:
212 return ret;
213}
214
215static 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);
220 pm_runtime_disable(&pdev->dev);
221
222 priv->uioinfo->handler = NULL;
223 priv->uioinfo->irqcontrol = NULL;
224
225 /* kfree uioinfo for OF */
226 if (pdev->dev.of_node)
227 kfree(priv->uioinfo);
228
229 kfree(priv);
230 return 0;
231}
232
233static 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
250static const struct dev_pm_ops uio_pdrv_genirq_dev_pm_ops = {
251 .runtime_suspend = uio_pdrv_genirq_runtime_nop,
252 .runtime_resume = uio_pdrv_genirq_runtime_nop,
253};
254
255#ifdef CONFIG_OF
256static const struct of_device_id __devinitconst uio_of_genirq_match[] = {
257 { /* empty for now */ },
258};
259MODULE_DEVICE_TABLE(of, uio_of_genirq_match);
260#else
261# define uio_of_genirq_match NULL
262#endif
263
264static 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,
270 .pm = &uio_pdrv_genirq_dev_pm_ops,
271 .of_match_table = uio_of_genirq_match,
272 },
273};
274
275static int __init uio_pdrv_genirq_init(void)
276{
277 return platform_driver_register(&uio_pdrv_genirq);
278}
279
280static void __exit uio_pdrv_genirq_exit(void)
281{
282 platform_driver_unregister(&uio_pdrv_genirq);
283}
284
285module_init(uio_pdrv_genirq_init);
286module_exit(uio_pdrv_genirq_exit);
287
288MODULE_AUTHOR("Magnus Damm");
289MODULE_DESCRIPTION("Userspace I/O platform driver with generic IRQ handling");
290MODULE_LICENSE("GPL v2");
291MODULE_ALIAS("platform:" DRIVER_NAME);