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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// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * drivers/uio/uio_pdrv_genirq.c
4 *
5 * Userspace I/O platform driver with generic IRQ handling code.
6 *
7 * Copyright (C) 2008 Magnus Damm
8 *
9 * Based on uio_pdrv.c by Uwe Kleine-Koenig,
10 * Copyright (C) 2008 by Digi International Inc.
11 * All rights reserved.
12 */
13
14#include <linux/platform_device.h>
15#include <linux/uio_driver.h>
16#include <linux/spinlock.h>
17#include <linux/bitops.h>
18#include <linux/module.h>
19#include <linux/interrupt.h>
20#include <linux/stringify.h>
21#include <linux/pm_runtime.h>
22#include <linux/slab.h>
23#include <linux/irq.h>
24
25#include <linux/of.h>
26#include <linux/of_platform.h>
27#include <linux/of_address.h>
28
29#define DRIVER_NAME "uio_pdrv_genirq"
30
31struct uio_pdrv_genirq_platdata {
32 struct uio_info *uioinfo;
33 spinlock_t lock;
34 unsigned long flags;
35 struct platform_device *pdev;
36};
37
38/* Bits in uio_pdrv_genirq_platdata.flags */
39enum {
40 UIO_IRQ_DISABLED = 0,
41};
42
43static int uio_pdrv_genirq_open(struct uio_info *info, struct inode *inode)
44{
45 struct uio_pdrv_genirq_platdata *priv = info->priv;
46
47 /* Wait until the Runtime PM code has woken up the device */
48 pm_runtime_get_sync(&priv->pdev->dev);
49 return 0;
50}
51
52static int uio_pdrv_genirq_release(struct uio_info *info, struct inode *inode)
53{
54 struct uio_pdrv_genirq_platdata *priv = info->priv;
55
56 /* Tell the Runtime PM code that the device has become idle */
57 pm_runtime_put_sync(&priv->pdev->dev);
58 return 0;
59}
60
61static irqreturn_t uio_pdrv_genirq_handler(int irq, struct uio_info *dev_info)
62{
63 struct uio_pdrv_genirq_platdata *priv = dev_info->priv;
64
65 /* Just disable the interrupt in the interrupt controller, and
66 * remember the state so we can allow user space to enable it later.
67 */
68
69 spin_lock(&priv->lock);
70 if (!__test_and_set_bit(UIO_IRQ_DISABLED, &priv->flags))
71 disable_irq_nosync(irq);
72 spin_unlock(&priv->lock);
73
74 return IRQ_HANDLED;
75}
76
77static int uio_pdrv_genirq_irqcontrol(struct uio_info *dev_info, s32 irq_on)
78{
79 struct uio_pdrv_genirq_platdata *priv = dev_info->priv;
80 unsigned long flags;
81
82 /* Allow user space to enable and disable the interrupt
83 * in the interrupt controller, but keep track of the
84 * state to prevent per-irq depth damage.
85 *
86 * Serialize this operation to support multiple tasks and concurrency
87 * with irq handler on SMP systems.
88 */
89
90 spin_lock_irqsave(&priv->lock, flags);
91 if (irq_on) {
92 if (__test_and_clear_bit(UIO_IRQ_DISABLED, &priv->flags))
93 enable_irq(dev_info->irq);
94 } else {
95 if (!__test_and_set_bit(UIO_IRQ_DISABLED, &priv->flags))
96 disable_irq_nosync(dev_info->irq);
97 }
98 spin_unlock_irqrestore(&priv->lock, flags);
99
100 return 0;
101}
102
103static void uio_pdrv_genirq_cleanup(void *data)
104{
105 struct device *dev = data;
106
107 pm_runtime_disable(dev);
108}
109
110static int uio_pdrv_genirq_probe(struct platform_device *pdev)
111{
112 struct uio_info *uioinfo = dev_get_platdata(&pdev->dev);
113 struct device_node *node = pdev->dev.of_node;
114 struct uio_pdrv_genirq_platdata *priv;
115 struct uio_mem *uiomem;
116 int ret = -EINVAL;
117 int i;
118
119 if (node) {
120 const char *name;
121
122 /* alloc uioinfo for one device */
123 uioinfo = devm_kzalloc(&pdev->dev, sizeof(*uioinfo),
124 GFP_KERNEL);
125 if (!uioinfo) {
126 dev_err(&pdev->dev, "unable to kmalloc\n");
127 return -ENOMEM;
128 }
129
130 if (!of_property_read_string(node, "linux,uio-name", &name))
131 uioinfo->name = devm_kstrdup(&pdev->dev, name, GFP_KERNEL);
132 else
133 uioinfo->name = devm_kasprintf(&pdev->dev, GFP_KERNEL,
134 "%pOFn", node);
135
136 uioinfo->version = "devicetree";
137 /* Multiple IRQs are not supported */
138 }
139
140 if (!uioinfo || !uioinfo->name || !uioinfo->version) {
141 dev_err(&pdev->dev, "missing platform_data\n");
142 return ret;
143 }
144
145 if (uioinfo->handler || uioinfo->irqcontrol ||
146 uioinfo->irq_flags & IRQF_SHARED) {
147 dev_err(&pdev->dev, "interrupt configuration error\n");
148 return ret;
149 }
150
151 priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
152 if (!priv) {
153 dev_err(&pdev->dev, "unable to kmalloc\n");
154 return -ENOMEM;
155 }
156
157 priv->uioinfo = uioinfo;
158 spin_lock_init(&priv->lock);
159 priv->flags = 0; /* interrupt is enabled to begin with */
160 priv->pdev = pdev;
161
162 if (!uioinfo->irq) {
163 ret = platform_get_irq_optional(pdev, 0);
164 uioinfo->irq = ret;
165 if (ret == -ENXIO)
166 uioinfo->irq = UIO_IRQ_NONE;
167 else if (ret == -EPROBE_DEFER)
168 return ret;
169 else if (ret < 0) {
170 dev_err(&pdev->dev, "failed to get IRQ\n");
171 return ret;
172 }
173 }
174
175 if (uioinfo->irq) {
176 struct irq_data *irq_data = irq_get_irq_data(uioinfo->irq);
177
178 /*
179 * If a level interrupt, dont do lazy disable. Otherwise the
180 * irq will fire again since clearing of the actual cause, on
181 * device level, is done in userspace
182 * irqd_is_level_type() isn't used since isn't valid until
183 * irq is configured.
184 */
185 if (irq_data &&
186 irqd_get_trigger_type(irq_data) & IRQ_TYPE_LEVEL_MASK) {
187 dev_dbg(&pdev->dev, "disable lazy unmask\n");
188 irq_set_status_flags(uioinfo->irq, IRQ_DISABLE_UNLAZY);
189 }
190 }
191
192 uiomem = &uioinfo->mem[0];
193
194 for (i = 0; i < pdev->num_resources; ++i) {
195 struct resource *r = &pdev->resource[i];
196
197 if (r->flags != IORESOURCE_MEM)
198 continue;
199
200 if (uiomem >= &uioinfo->mem[MAX_UIO_MAPS]) {
201 dev_warn(&pdev->dev, "device has more than "
202 __stringify(MAX_UIO_MAPS)
203 " I/O memory resources.\n");
204 break;
205 }
206
207 uiomem->memtype = UIO_MEM_PHYS;
208 uiomem->addr = r->start & PAGE_MASK;
209 uiomem->offs = r->start & ~PAGE_MASK;
210 uiomem->size = (uiomem->offs + resource_size(r)
211 + PAGE_SIZE - 1) & PAGE_MASK;
212 uiomem->name = r->name;
213 ++uiomem;
214 }
215
216 while (uiomem < &uioinfo->mem[MAX_UIO_MAPS]) {
217 uiomem->size = 0;
218 ++uiomem;
219 }
220
221 /* This driver requires no hardware specific kernel code to handle
222 * interrupts. Instead, the interrupt handler simply disables the
223 * interrupt in the interrupt controller. User space is responsible
224 * for performing hardware specific acknowledge and re-enabling of
225 * the interrupt in the interrupt controller.
226 *
227 * Interrupt sharing is not supported.
228 */
229
230 uioinfo->handler = uio_pdrv_genirq_handler;
231 uioinfo->irqcontrol = uio_pdrv_genirq_irqcontrol;
232 uioinfo->open = uio_pdrv_genirq_open;
233 uioinfo->release = uio_pdrv_genirq_release;
234 uioinfo->priv = priv;
235
236 /* Enable Runtime PM for this device:
237 * The device starts in suspended state to allow the hardware to be
238 * turned off by default. The Runtime PM bus code should power on the
239 * hardware and enable clocks at open().
240 */
241 pm_runtime_enable(&pdev->dev);
242
243 ret = devm_add_action_or_reset(&pdev->dev, uio_pdrv_genirq_cleanup,
244 &pdev->dev);
245 if (ret)
246 return ret;
247
248 ret = devm_uio_register_device(&pdev->dev, priv->uioinfo);
249 if (ret)
250 dev_err(&pdev->dev, "unable to register uio device\n");
251
252 return ret;
253}
254
255static int uio_pdrv_genirq_runtime_nop(struct device *dev)
256{
257 /* Runtime PM callback shared between ->runtime_suspend()
258 * and ->runtime_resume(). Simply returns success.
259 *
260 * In this driver pm_runtime_get_sync() and pm_runtime_put_sync()
261 * are used at open() and release() time. This allows the
262 * Runtime PM code to turn off power to the device while the
263 * device is unused, ie before open() and after release().
264 *
265 * This Runtime PM callback does not need to save or restore
266 * any registers since user space is responsbile for hardware
267 * register reinitialization after open().
268 */
269 return 0;
270}
271
272static const struct dev_pm_ops uio_pdrv_genirq_dev_pm_ops = {
273 .runtime_suspend = uio_pdrv_genirq_runtime_nop,
274 .runtime_resume = uio_pdrv_genirq_runtime_nop,
275};
276
277#ifdef CONFIG_OF
278static struct of_device_id uio_of_genirq_match[] = {
279 { /* This is filled with module_parm */ },
280 { /* Sentinel */ },
281};
282MODULE_DEVICE_TABLE(of, uio_of_genirq_match);
283module_param_string(of_id, uio_of_genirq_match[0].compatible, 128, 0);
284MODULE_PARM_DESC(of_id, "Openfirmware id of the device to be handled by uio");
285#endif
286
287static struct platform_driver uio_pdrv_genirq = {
288 .probe = uio_pdrv_genirq_probe,
289 .driver = {
290 .name = DRIVER_NAME,
291 .pm = &uio_pdrv_genirq_dev_pm_ops,
292 .of_match_table = of_match_ptr(uio_of_genirq_match),
293 },
294};
295
296module_platform_driver(uio_pdrv_genirq);
297
298MODULE_AUTHOR("Magnus Damm");
299MODULE_DESCRIPTION("Userspace I/O platform driver with generic IRQ handling");
300MODULE_LICENSE("GPL v2");
301MODULE_ALIAS("platform:" DRIVER_NAME);