blob: d8bbe0783cdcdfe429ba1e032a27096c79c3c4ca [file] [log] [blame]
Damian Hobson-Garcia0a0c3b52012-09-25 15:09:11 +09001/*
2 * drivers/uio/uio_dmem_genirq.c
3 *
4 * Userspace I/O platform driver with generic IRQ handling code.
5 *
6 * Copyright (C) 2012 Damian Hobson-Garcia
7 *
8 * Based on uio_pdrv_genirq.c by Magnus Damm
9 *
10 * This program is free software; you can redistribute it and/or modify it
11 * under the terms of the GNU General Public License version 2 as published by
12 * the Free Software Foundation.
13 */
14
15#include <linux/platform_device.h>
16#include <linux/uio_driver.h>
17#include <linux/spinlock.h>
18#include <linux/bitops.h>
19#include <linux/module.h>
20#include <linux/interrupt.h>
21#include <linux/platform_data/uio_dmem_genirq.h>
22#include <linux/stringify.h>
23#include <linux/pm_runtime.h>
24#include <linux/dma-mapping.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_dmem_genirq"
32
33struct uio_dmem_genirq_platdata {
34 struct uio_info *uioinfo;
35 spinlock_t lock;
36 unsigned long flags;
37 struct platform_device *pdev;
38 unsigned int dmem_region_start;
39 unsigned int num_dmem_regions;
Damian Hobson-Garcia24fce612012-11-16 14:46:09 +090040 void *dmem_region_vaddr[MAX_UIO_MAPS];
Damian Hobson-Garcia0a0c3b52012-09-25 15:09:11 +090041 struct mutex alloc_lock;
42 unsigned int refcnt;
43};
44
45static int uio_dmem_genirq_open(struct uio_info *info, struct inode *inode)
46{
47 struct uio_dmem_genirq_platdata *priv = info->priv;
48 struct uio_mem *uiomem;
49 int ret = 0;
Damian Hobson-Garcia24fce612012-11-16 14:46:09 +090050 int dmem_region = priv->dmem_region_start;
Damian Hobson-Garcia0a0c3b52012-09-25 15:09:11 +090051
52 uiomem = &priv->uioinfo->mem[priv->dmem_region_start];
53
54 mutex_lock(&priv->alloc_lock);
55 while (!priv->refcnt && uiomem < &priv->uioinfo->mem[MAX_UIO_MAPS]) {
56 void *addr;
57 if (!uiomem->size)
58 break;
59
60 addr = dma_alloc_coherent(&priv->pdev->dev, uiomem->size,
61 (dma_addr_t *)&uiomem->addr, GFP_KERNEL);
62 if (!addr) {
63 ret = -ENOMEM;
64 break;
65 }
Damian Hobson-Garcia24fce612012-11-16 14:46:09 +090066 priv->dmem_region_vaddr[dmem_region++] = addr;
Damian Hobson-Garcia0a0c3b52012-09-25 15:09:11 +090067 ++uiomem;
68 }
69 priv->refcnt++;
70
71 mutex_unlock(&priv->alloc_lock);
72 /* Wait until the Runtime PM code has woken up the device */
73 pm_runtime_get_sync(&priv->pdev->dev);
74 return ret;
75}
76
77static int uio_dmem_genirq_release(struct uio_info *info, struct inode *inode)
78{
79 struct uio_dmem_genirq_platdata *priv = info->priv;
80 struct uio_mem *uiomem;
Damian Hobson-Garcia24fce612012-11-16 14:46:09 +090081 int dmem_region = priv->dmem_region_start;
Damian Hobson-Garcia0a0c3b52012-09-25 15:09:11 +090082
83 /* Tell the Runtime PM code that the device has become idle */
84 pm_runtime_put_sync(&priv->pdev->dev);
85
86 uiomem = &priv->uioinfo->mem[priv->dmem_region_start];
87
88 mutex_lock(&priv->alloc_lock);
89
90 priv->refcnt--;
91 while (!priv->refcnt && uiomem < &priv->uioinfo->mem[MAX_UIO_MAPS]) {
92 if (!uiomem->size)
93 break;
94
95 dma_free_coherent(&priv->pdev->dev, uiomem->size,
Damian Hobson-Garcia24fce612012-11-16 14:46:09 +090096 priv->dmem_region_vaddr[dmem_region++],
97 uiomem->addr);
Damian Hobson-Garcia0a0c3b52012-09-25 15:09:11 +090098 uiomem->addr = DMA_ERROR_CODE;
99 ++uiomem;
100 }
101
102 mutex_unlock(&priv->alloc_lock);
103 return 0;
104}
105
106static irqreturn_t uio_dmem_genirq_handler(int irq, struct uio_info *dev_info)
107{
108 struct uio_dmem_genirq_platdata *priv = dev_info->priv;
109
110 /* Just disable the interrupt in the interrupt controller, and
111 * remember the state so we can allow user space to enable it later.
112 */
113
114 if (!test_and_set_bit(0, &priv->flags))
115 disable_irq_nosync(irq);
116
117 return IRQ_HANDLED;
118}
119
120static int uio_dmem_genirq_irqcontrol(struct uio_info *dev_info, s32 irq_on)
121{
122 struct uio_dmem_genirq_platdata *priv = dev_info->priv;
123 unsigned long flags;
124
125 /* Allow user space to enable and disable the interrupt
126 * in the interrupt controller, but keep track of the
127 * state to prevent per-irq depth damage.
128 *
129 * Serialize this operation to support multiple tasks.
130 */
131
132 spin_lock_irqsave(&priv->lock, flags);
133 if (irq_on) {
134 if (test_and_clear_bit(0, &priv->flags))
135 enable_irq(dev_info->irq);
136 } else {
137 if (!test_and_set_bit(0, &priv->flags))
138 disable_irq(dev_info->irq);
139 }
140 spin_unlock_irqrestore(&priv->lock, flags);
141
142 return 0;
143}
144
145static int uio_dmem_genirq_probe(struct platform_device *pdev)
146{
147 struct uio_dmem_genirq_pdata *pdata = pdev->dev.platform_data;
148 struct uio_info *uioinfo = &pdata->uioinfo;
149 struct uio_dmem_genirq_platdata *priv;
150 struct uio_mem *uiomem;
151 int ret = -EINVAL;
152 int i;
153
154 if (!uioinfo) {
155 int irq;
156
157 /* alloc uioinfo for one device */
158 uioinfo = kzalloc(sizeof(*uioinfo), GFP_KERNEL);
159 if (!uioinfo) {
160 ret = -ENOMEM;
161 dev_err(&pdev->dev, "unable to kmalloc\n");
162 goto bad2;
163 }
164 uioinfo->name = pdev->dev.of_node->name;
165 uioinfo->version = "devicetree";
166
167 /* Multiple IRQs are not supported */
168 irq = platform_get_irq(pdev, 0);
169 if (irq == -ENXIO)
170 uioinfo->irq = UIO_IRQ_NONE;
171 else
172 uioinfo->irq = irq;
173 }
174
175 if (!uioinfo || !uioinfo->name || !uioinfo->version) {
176 dev_err(&pdev->dev, "missing platform_data\n");
177 goto bad0;
178 }
179
180 if (uioinfo->handler || uioinfo->irqcontrol ||
181 uioinfo->irq_flags & IRQF_SHARED) {
182 dev_err(&pdev->dev, "interrupt configuration error\n");
183 goto bad0;
184 }
185
186 priv = kzalloc(sizeof(*priv), GFP_KERNEL);
187 if (!priv) {
188 ret = -ENOMEM;
189 dev_err(&pdev->dev, "unable to kmalloc\n");
190 goto bad0;
191 }
192
193 dma_set_coherent_mask(&pdev->dev, DMA_BIT_MASK(32));
194
195 priv->uioinfo = uioinfo;
196 spin_lock_init(&priv->lock);
197 priv->flags = 0; /* interrupt is enabled to begin with */
198 priv->pdev = pdev;
199 mutex_init(&priv->alloc_lock);
200
201 if (!uioinfo->irq) {
202 ret = platform_get_irq(pdev, 0);
203 if (ret < 0) {
204 dev_err(&pdev->dev, "failed to get IRQ\n");
205 goto bad0;
206 }
207 uioinfo->irq = ret;
208 }
209 uiomem = &uioinfo->mem[0];
210
211 for (i = 0; i < pdev->num_resources; ++i) {
212 struct resource *r = &pdev->resource[i];
213
214 if (r->flags != IORESOURCE_MEM)
215 continue;
216
217 if (uiomem >= &uioinfo->mem[MAX_UIO_MAPS]) {
218 dev_warn(&pdev->dev, "device has more than "
219 __stringify(MAX_UIO_MAPS)
220 " I/O memory resources.\n");
221 break;
222 }
223
224 uiomem->memtype = UIO_MEM_PHYS;
225 uiomem->addr = r->start;
226 uiomem->size = resource_size(r);
227 ++uiomem;
228 }
229
230 priv->dmem_region_start = i;
231 priv->num_dmem_regions = pdata->num_dynamic_regions;
232
233 for (i = 0; i < pdata->num_dynamic_regions; ++i) {
234 if (uiomem >= &uioinfo->mem[MAX_UIO_MAPS]) {
235 dev_warn(&pdev->dev, "device has more than "
236 __stringify(MAX_UIO_MAPS)
237 " dynamic and fixed memory regions.\n");
238 break;
239 }
240 uiomem->memtype = UIO_MEM_PHYS;
241 uiomem->addr = DMA_ERROR_CODE;
242 uiomem->size = pdata->dynamic_region_sizes[i];
243 ++uiomem;
244 }
245
246 while (uiomem < &uioinfo->mem[MAX_UIO_MAPS]) {
247 uiomem->size = 0;
248 ++uiomem;
249 }
250
251 /* This driver requires no hardware specific kernel code to handle
252 * interrupts. Instead, the interrupt handler simply disables the
253 * interrupt in the interrupt controller. User space is responsible
254 * for performing hardware specific acknowledge and re-enabling of
255 * the interrupt in the interrupt controller.
256 *
257 * Interrupt sharing is not supported.
258 */
259
260 uioinfo->handler = uio_dmem_genirq_handler;
261 uioinfo->irqcontrol = uio_dmem_genirq_irqcontrol;
262 uioinfo->open = uio_dmem_genirq_open;
263 uioinfo->release = uio_dmem_genirq_release;
264 uioinfo->priv = priv;
265
266 /* Enable Runtime PM for this device:
267 * The device starts in suspended state to allow the hardware to be
268 * turned off by default. The Runtime PM bus code should power on the
269 * hardware and enable clocks at open().
270 */
271 pm_runtime_enable(&pdev->dev);
272
273 ret = uio_register_device(&pdev->dev, priv->uioinfo);
274 if (ret) {
275 dev_err(&pdev->dev, "unable to register uio device\n");
276 goto bad1;
277 }
278
279 platform_set_drvdata(pdev, priv);
280 return 0;
281 bad1:
282 kfree(priv);
283 pm_runtime_disable(&pdev->dev);
284 bad0:
285 /* kfree uioinfo for OF */
286 if (pdev->dev.of_node)
287 kfree(uioinfo);
288 bad2:
289 return ret;
290}
291
292static int uio_dmem_genirq_remove(struct platform_device *pdev)
293{
294 struct uio_dmem_genirq_platdata *priv = platform_get_drvdata(pdev);
295
296 uio_unregister_device(priv->uioinfo);
297 pm_runtime_disable(&pdev->dev);
298
299 priv->uioinfo->handler = NULL;
300 priv->uioinfo->irqcontrol = NULL;
301
302 /* kfree uioinfo for OF */
303 if (pdev->dev.of_node)
304 kfree(priv->uioinfo);
305
306 kfree(priv);
307 return 0;
308}
309
310static int uio_dmem_genirq_runtime_nop(struct device *dev)
311{
312 /* Runtime PM callback shared between ->runtime_suspend()
313 * and ->runtime_resume(). Simply returns success.
314 *
315 * In this driver pm_runtime_get_sync() and pm_runtime_put_sync()
316 * are used at open() and release() time. This allows the
317 * Runtime PM code to turn off power to the device while the
318 * device is unused, ie before open() and after release().
319 *
320 * This Runtime PM callback does not need to save or restore
321 * any registers since user space is responsbile for hardware
322 * register reinitialization after open().
323 */
324 return 0;
325}
326
327static const struct dev_pm_ops uio_dmem_genirq_dev_pm_ops = {
328 .runtime_suspend = uio_dmem_genirq_runtime_nop,
329 .runtime_resume = uio_dmem_genirq_runtime_nop,
330};
331
332#ifdef CONFIG_OF
333static const struct of_device_id uio_of_genirq_match[] = {
334 { /* empty for now */ },
335};
336MODULE_DEVICE_TABLE(of, uio_of_genirq_match);
337#else
338# define uio_of_genirq_match NULL
339#endif
340
341static struct platform_driver uio_dmem_genirq = {
342 .probe = uio_dmem_genirq_probe,
343 .remove = uio_dmem_genirq_remove,
344 .driver = {
345 .name = DRIVER_NAME,
346 .owner = THIS_MODULE,
347 .pm = &uio_dmem_genirq_dev_pm_ops,
348 .of_match_table = uio_of_genirq_match,
349 },
350};
351
352module_platform_driver(uio_dmem_genirq);
353
354MODULE_AUTHOR("Damian Hobson-Garcia");
355MODULE_DESCRIPTION("Userspace I/O platform driver with dynamic memory.");
356MODULE_LICENSE("GPL v2");
357MODULE_ALIAS("platform:" DRIVER_NAME);