Linux Audio

Check our new training course

Linux BSP development engineering services

Need help to port Linux and bootloaders to your hardware?
Loading...
v6.13.7
  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * drivers/uio/uio_dmem_genirq.c
  4 *
  5 * Userspace I/O platform driver with generic IRQ handling code.
  6 *
  7 * Copyright (C) 2012 Damian Hobson-Garcia
  8 *
  9 * Based on uio_pdrv_genirq.c by Magnus Damm
 10 */
 11
 12#include <linux/platform_device.h>
 13#include <linux/uio_driver.h>
 14#include <linux/spinlock.h>
 15#include <linux/bitops.h>
 16#include <linux/module.h>
 17#include <linux/interrupt.h>
 18#include <linux/platform_data/uio_dmem_genirq.h>
 19#include <linux/stringify.h>
 20#include <linux/pm_runtime.h>
 21#include <linux/dma-mapping.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_dmem_genirq"
 30#define DMEM_MAP_ERROR (~0)
 31
 32struct uio_dmem_genirq_platdata {
 33	struct uio_info *uioinfo;
 34	spinlock_t lock;
 35	unsigned long flags;
 36	struct platform_device *pdev;
 37	unsigned int dmem_region_start;
 38	unsigned int num_dmem_regions;
 
 39	struct mutex alloc_lock;
 40	unsigned int refcnt;
 41};
 42
 43/* Bits in uio_dmem_genirq_platdata.flags */
 44enum {
 45	UIO_IRQ_DISABLED = 0,
 46};
 47
 48static int uio_dmem_genirq_open(struct uio_info *info, struct inode *inode)
 49{
 50	struct uio_dmem_genirq_platdata *priv = info->priv;
 51	struct uio_mem *uiomem;
 
 
 52
 53	uiomem = &priv->uioinfo->mem[priv->dmem_region_start];
 54
 55	mutex_lock(&priv->alloc_lock);
 56	while (!priv->refcnt && uiomem < &priv->uioinfo->mem[MAX_UIO_MAPS]) {
 57		void *addr;
 58		if (!uiomem->size)
 59			break;
 60
 61		addr = dma_alloc_coherent(&priv->pdev->dev, uiomem->size,
 62					  &uiomem->dma_addr, GFP_KERNEL);
 63		uiomem->addr = addr ? (uintptr_t) addr : DMEM_MAP_ERROR;
 
 
 
 64		++uiomem;
 65	}
 66	priv->refcnt++;
 67
 68	mutex_unlock(&priv->alloc_lock);
 69	/* Wait until the Runtime PM code has woken up the device */
 70	pm_runtime_get_sync(&priv->pdev->dev);
 71	return 0;
 72}
 73
 74static int uio_dmem_genirq_release(struct uio_info *info, struct inode *inode)
 75{
 76	struct uio_dmem_genirq_platdata *priv = info->priv;
 77	struct uio_mem *uiomem;
 
 78
 79	/* Tell the Runtime PM code that the device has become idle */
 80	pm_runtime_put_sync(&priv->pdev->dev);
 81
 82	uiomem = &priv->uioinfo->mem[priv->dmem_region_start];
 83
 84	mutex_lock(&priv->alloc_lock);
 85
 86	priv->refcnt--;
 87	while (!priv->refcnt && uiomem < &priv->uioinfo->mem[MAX_UIO_MAPS]) {
 88		if (!uiomem->size)
 89			break;
 90		if (uiomem->addr) {
 91			dma_free_coherent(uiomem->dma_device, uiomem->size,
 92					  (void *) (uintptr_t) uiomem->addr,
 93					  uiomem->dma_addr);
 94		}
 95		uiomem->addr = DMEM_MAP_ERROR;
 
 96		++uiomem;
 97	}
 98
 99	mutex_unlock(&priv->alloc_lock);
100	return 0;
101}
102
103static irqreturn_t uio_dmem_genirq_handler(int irq, struct uio_info *dev_info)
104{
105	struct uio_dmem_genirq_platdata *priv = dev_info->priv;
106
107	/* Just disable the interrupt in the interrupt controller, and
108	 * remember the state so we can allow user space to enable it later.
109	 */
110
111	spin_lock(&priv->lock);
112	if (!__test_and_set_bit(UIO_IRQ_DISABLED, &priv->flags))
113		disable_irq_nosync(irq);
114	spin_unlock(&priv->lock);
115
116	return IRQ_HANDLED;
117}
118
119static int uio_dmem_genirq_irqcontrol(struct uio_info *dev_info, s32 irq_on)
120{
121	struct uio_dmem_genirq_platdata *priv = dev_info->priv;
122	unsigned long flags;
123
124	/* Allow user space to enable and disable the interrupt
125	 * in the interrupt controller, but keep track of the
126	 * state to prevent per-irq depth damage.
127	 *
128	 * Serialize this operation to support multiple tasks and concurrency
129	 * with irq handler on SMP systems.
130	 */
131
132	spin_lock_irqsave(&priv->lock, flags);
133	if (irq_on) {
134		if (__test_and_clear_bit(UIO_IRQ_DISABLED, &priv->flags))
135			enable_irq(dev_info->irq);
136	} else {
137		if (!__test_and_set_bit(UIO_IRQ_DISABLED, &priv->flags))
138			disable_irq_nosync(dev_info->irq);
139	}
140	spin_unlock_irqrestore(&priv->lock, flags);
141
142	return 0;
143}
144
145static void uio_dmem_genirq_pm_disable(void *data)
146{
147	struct device *dev = data;
148
149	pm_runtime_disable(dev);
150}
151
152static int uio_dmem_genirq_probe(struct platform_device *pdev)
153{
154	struct uio_dmem_genirq_pdata *pdata = dev_get_platdata(&pdev->dev);
155	struct uio_info *uioinfo = &pdata->uioinfo;
156	struct uio_dmem_genirq_platdata *priv;
157	struct uio_mem *uiomem;
158	int ret = -EINVAL;
159	int i;
160
161	if (pdev->dev.of_node) {
 
 
162		/* alloc uioinfo for one device */
163		uioinfo = devm_kzalloc(&pdev->dev, sizeof(*uioinfo), GFP_KERNEL);
164		if (!uioinfo) {
 
165			dev_err(&pdev->dev, "unable to kmalloc\n");
166			return -ENOMEM;
167		}
168		uioinfo->name = devm_kasprintf(&pdev->dev, GFP_KERNEL, "%pOFn",
169					       pdev->dev.of_node);
170		uioinfo->version = "devicetree";
 
 
 
 
 
 
 
171	}
172
173	if (!uioinfo || !uioinfo->name || !uioinfo->version) {
174		dev_err(&pdev->dev, "missing platform_data\n");
175		return -EINVAL;
176	}
177
178	if (uioinfo->handler || uioinfo->irqcontrol ||
179	    uioinfo->irq_flags & IRQF_SHARED) {
180		dev_err(&pdev->dev, "interrupt configuration error\n");
181		return -EINVAL;
182	}
183
184	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
185	if (!priv) {
 
186		dev_err(&pdev->dev, "unable to kmalloc\n");
187		return -ENOMEM;
188	}
189
190	ret = dma_set_coherent_mask(&pdev->dev, DMA_BIT_MASK(32));
191	if (ret) {
192		dev_err(&pdev->dev, "DMA enable failed\n");
193		return ret;
194	}
195
196	priv->uioinfo = uioinfo;
197	spin_lock_init(&priv->lock);
198	priv->flags = 0; /* interrupt is enabled to begin with */
199	priv->pdev = pdev;
200	mutex_init(&priv->alloc_lock);
201
202	if (!uioinfo->irq) {
203		/* Multiple IRQs are not supported */
204		ret = platform_get_irq(pdev, 0);
205		if (ret == -ENXIO && pdev->dev.of_node)
206			ret = UIO_IRQ_NONE;
207		else if (ret < 0)
208			return ret;
209		uioinfo->irq = ret;
210	}
211
212	if (uioinfo->irq) {
213		/*
214		 * If a level interrupt, dont do lazy disable. Otherwise the
215		 * irq will fire again since clearing of the actual cause, on
216		 * device level, is done in userspace
217		 * irqd_is_level_type() isn't used since isn't valid until
218		 * irq is configured.
219		 */
220		if (irq_get_trigger_type(uioinfo->irq) & IRQ_TYPE_LEVEL_MASK) {
221			dev_dbg(&pdev->dev, "disable lazy unmask\n");
222			irq_set_status_flags(uioinfo->irq, IRQ_DISABLE_UNLAZY);
223		}
224	}
225
226	uiomem = &uioinfo->mem[0];
227
228	for (i = 0; i < pdev->num_resources; ++i) {
229		struct resource *r = &pdev->resource[i];
230
231		if (r->flags != IORESOURCE_MEM)
232			continue;
233
234		if (uiomem >= &uioinfo->mem[MAX_UIO_MAPS]) {
235			dev_warn(&pdev->dev, "device has more than "
236					__stringify(MAX_UIO_MAPS)
237					" I/O memory resources.\n");
238			break;
239		}
240
241		uiomem->memtype = UIO_MEM_PHYS;
242		uiomem->addr = r->start;
243		uiomem->size = resource_size(r);
244		++uiomem;
245	}
246
247	priv->dmem_region_start = uiomem - &uioinfo->mem[0];
248	priv->num_dmem_regions = pdata->num_dynamic_regions;
249
250	for (i = 0; i < pdata->num_dynamic_regions; ++i) {
251		if (uiomem >= &uioinfo->mem[MAX_UIO_MAPS]) {
252			dev_warn(&pdev->dev, "device has more than "
253					__stringify(MAX_UIO_MAPS)
254					" dynamic and fixed memory regions.\n");
255			break;
256		}
257		uiomem->memtype = UIO_MEM_DMA_COHERENT;
258		uiomem->dma_device = &pdev->dev;
259		uiomem->addr = DMEM_MAP_ERROR;
260		uiomem->size = pdata->dynamic_region_sizes[i];
261		++uiomem;
262	}
263
264	while (uiomem < &uioinfo->mem[MAX_UIO_MAPS]) {
265		uiomem->size = 0;
266		++uiomem;
267	}
268
269	/* This driver requires no hardware specific kernel code to handle
270	 * interrupts. Instead, the interrupt handler simply disables the
271	 * interrupt in the interrupt controller. User space is responsible
272	 * for performing hardware specific acknowledge and re-enabling of
273	 * the interrupt in the interrupt controller.
274	 *
275	 * Interrupt sharing is not supported.
276	 */
277
278	uioinfo->handler = uio_dmem_genirq_handler;
279	uioinfo->irqcontrol = uio_dmem_genirq_irqcontrol;
280	uioinfo->open = uio_dmem_genirq_open;
281	uioinfo->release = uio_dmem_genirq_release;
282	uioinfo->priv = priv;
283
284	/* Enable Runtime PM for this device:
285	 * The device starts in suspended state to allow the hardware to be
286	 * turned off by default. The Runtime PM bus code should power on the
287	 * hardware and enable clocks at open().
288	 */
289	pm_runtime_enable(&pdev->dev);
290
291	ret = devm_add_action_or_reset(&pdev->dev, uio_dmem_genirq_pm_disable, &pdev->dev);
292	if (ret)
293		return ret;
 
 
 
294
295	return devm_uio_register_device(&pdev->dev, priv->uioinfo);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
296}
297
298static int uio_dmem_genirq_runtime_nop(struct device *dev)
299{
300	/* Runtime PM callback shared between ->runtime_suspend()
301	 * and ->runtime_resume(). Simply returns success.
302	 *
303	 * In this driver pm_runtime_get_sync() and pm_runtime_put_sync()
304	 * are used at open() and release() time. This allows the
305	 * Runtime PM code to turn off power to the device while the
306	 * device is unused, ie before open() and after release().
307	 *
308	 * This Runtime PM callback does not need to save or restore
309	 * any registers since user space is responsbile for hardware
310	 * register reinitialization after open().
311	 */
312	return 0;
313}
314
315static const struct dev_pm_ops uio_dmem_genirq_dev_pm_ops = {
316	.runtime_suspend = uio_dmem_genirq_runtime_nop,
317	.runtime_resume = uio_dmem_genirq_runtime_nop,
318};
319
320#ifdef CONFIG_OF
321static const struct of_device_id uio_of_genirq_match[] = {
322	{ /* empty for now */ },
323};
324MODULE_DEVICE_TABLE(of, uio_of_genirq_match);
325#endif
326
327static struct platform_driver uio_dmem_genirq = {
328	.probe = uio_dmem_genirq_probe,
 
329	.driver = {
330		.name = DRIVER_NAME,
331		.pm = &uio_dmem_genirq_dev_pm_ops,
332		.of_match_table = of_match_ptr(uio_of_genirq_match),
333	},
334};
335
336module_platform_driver(uio_dmem_genirq);
337
338MODULE_AUTHOR("Damian Hobson-Garcia");
339MODULE_DESCRIPTION("Userspace I/O platform driver with dynamic memory.");
340MODULE_LICENSE("GPL v2");
341MODULE_ALIAS("platform:" DRIVER_NAME);
v5.4
  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * drivers/uio/uio_dmem_genirq.c
  4 *
  5 * Userspace I/O platform driver with generic IRQ handling code.
  6 *
  7 * Copyright (C) 2012 Damian Hobson-Garcia
  8 *
  9 * Based on uio_pdrv_genirq.c by Magnus Damm
 10 */
 11
 12#include <linux/platform_device.h>
 13#include <linux/uio_driver.h>
 14#include <linux/spinlock.h>
 15#include <linux/bitops.h>
 16#include <linux/module.h>
 17#include <linux/interrupt.h>
 18#include <linux/platform_data/uio_dmem_genirq.h>
 19#include <linux/stringify.h>
 20#include <linux/pm_runtime.h>
 21#include <linux/dma-mapping.h>
 22#include <linux/slab.h>
 
 23
 24#include <linux/of.h>
 25#include <linux/of_platform.h>
 26#include <linux/of_address.h>
 27
 28#define DRIVER_NAME "uio_dmem_genirq"
 29#define DMEM_MAP_ERROR (~0)
 30
 31struct uio_dmem_genirq_platdata {
 32	struct uio_info *uioinfo;
 33	spinlock_t lock;
 34	unsigned long flags;
 35	struct platform_device *pdev;
 36	unsigned int dmem_region_start;
 37	unsigned int num_dmem_regions;
 38	void *dmem_region_vaddr[MAX_UIO_MAPS];
 39	struct mutex alloc_lock;
 40	unsigned int refcnt;
 41};
 42
 
 
 
 
 
 43static int uio_dmem_genirq_open(struct uio_info *info, struct inode *inode)
 44{
 45	struct uio_dmem_genirq_platdata *priv = info->priv;
 46	struct uio_mem *uiomem;
 47	int ret = 0;
 48	int dmem_region = priv->dmem_region_start;
 49
 50	uiomem = &priv->uioinfo->mem[priv->dmem_region_start];
 51
 52	mutex_lock(&priv->alloc_lock);
 53	while (!priv->refcnt && uiomem < &priv->uioinfo->mem[MAX_UIO_MAPS]) {
 54		void *addr;
 55		if (!uiomem->size)
 56			break;
 57
 58		addr = dma_alloc_coherent(&priv->pdev->dev, uiomem->size,
 59				(dma_addr_t *)&uiomem->addr, GFP_KERNEL);
 60		if (!addr) {
 61			uiomem->addr = DMEM_MAP_ERROR;
 62		}
 63		priv->dmem_region_vaddr[dmem_region++] = addr;
 64		++uiomem;
 65	}
 66	priv->refcnt++;
 67
 68	mutex_unlock(&priv->alloc_lock);
 69	/* Wait until the Runtime PM code has woken up the device */
 70	pm_runtime_get_sync(&priv->pdev->dev);
 71	return ret;
 72}
 73
 74static int uio_dmem_genirq_release(struct uio_info *info, struct inode *inode)
 75{
 76	struct uio_dmem_genirq_platdata *priv = info->priv;
 77	struct uio_mem *uiomem;
 78	int dmem_region = priv->dmem_region_start;
 79
 80	/* Tell the Runtime PM code that the device has become idle */
 81	pm_runtime_put_sync(&priv->pdev->dev);
 82
 83	uiomem = &priv->uioinfo->mem[priv->dmem_region_start];
 84
 85	mutex_lock(&priv->alloc_lock);
 86
 87	priv->refcnt--;
 88	while (!priv->refcnt && uiomem < &priv->uioinfo->mem[MAX_UIO_MAPS]) {
 89		if (!uiomem->size)
 90			break;
 91		if (priv->dmem_region_vaddr[dmem_region]) {
 92			dma_free_coherent(&priv->pdev->dev, uiomem->size,
 93					priv->dmem_region_vaddr[dmem_region],
 94					uiomem->addr);
 95		}
 96		uiomem->addr = DMEM_MAP_ERROR;
 97		++dmem_region;
 98		++uiomem;
 99	}
100
101	mutex_unlock(&priv->alloc_lock);
102	return 0;
103}
104
105static irqreturn_t uio_dmem_genirq_handler(int irq, struct uio_info *dev_info)
106{
107	struct uio_dmem_genirq_platdata *priv = dev_info->priv;
108
109	/* Just disable the interrupt in the interrupt controller, and
110	 * remember the state so we can allow user space to enable it later.
111	 */
112
113	if (!test_and_set_bit(0, &priv->flags))
 
114		disable_irq_nosync(irq);
 
115
116	return IRQ_HANDLED;
117}
118
119static int uio_dmem_genirq_irqcontrol(struct uio_info *dev_info, s32 irq_on)
120{
121	struct uio_dmem_genirq_platdata *priv = dev_info->priv;
122	unsigned long flags;
123
124	/* Allow user space to enable and disable the interrupt
125	 * in the interrupt controller, but keep track of the
126	 * state to prevent per-irq depth damage.
127	 *
128	 * Serialize this operation to support multiple tasks.
 
129	 */
130
131	spin_lock_irqsave(&priv->lock, flags);
132	if (irq_on) {
133		if (test_and_clear_bit(0, &priv->flags))
134			enable_irq(dev_info->irq);
135	} else {
136		if (!test_and_set_bit(0, &priv->flags))
137			disable_irq(dev_info->irq);
138	}
139	spin_unlock_irqrestore(&priv->lock, flags);
140
141	return 0;
142}
143
 
 
 
 
 
 
 
144static int uio_dmem_genirq_probe(struct platform_device *pdev)
145{
146	struct uio_dmem_genirq_pdata *pdata = dev_get_platdata(&pdev->dev);
147	struct uio_info *uioinfo = &pdata->uioinfo;
148	struct uio_dmem_genirq_platdata *priv;
149	struct uio_mem *uiomem;
150	int ret = -EINVAL;
151	int i;
152
153	if (pdev->dev.of_node) {
154		int irq;
155
156		/* alloc uioinfo for one device */
157		uioinfo = kzalloc(sizeof(*uioinfo), GFP_KERNEL);
158		if (!uioinfo) {
159			ret = -ENOMEM;
160			dev_err(&pdev->dev, "unable to kmalloc\n");
161			goto bad2;
162		}
163		uioinfo->name = devm_kasprintf(&pdev->dev, GFP_KERNEL, "%pOFn",
164					       pdev->dev.of_node);
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			goto bad1;
 
 
205		uioinfo->irq = ret;
206	}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
207	uiomem = &uioinfo->mem[0];
208
209	for (i = 0; i < pdev->num_resources; ++i) {
210		struct resource *r = &pdev->resource[i];
211
212		if (r->flags != IORESOURCE_MEM)
213			continue;
214
215		if (uiomem >= &uioinfo->mem[MAX_UIO_MAPS]) {
216			dev_warn(&pdev->dev, "device has more than "
217					__stringify(MAX_UIO_MAPS)
218					" I/O memory resources.\n");
219			break;
220		}
221
222		uiomem->memtype = UIO_MEM_PHYS;
223		uiomem->addr = r->start;
224		uiomem->size = resource_size(r);
225		++uiomem;
226	}
227
228	priv->dmem_region_start = uiomem - &uioinfo->mem[0];
229	priv->num_dmem_regions = pdata->num_dynamic_regions;
230
231	for (i = 0; i < pdata->num_dynamic_regions; ++i) {
232		if (uiomem >= &uioinfo->mem[MAX_UIO_MAPS]) {
233			dev_warn(&pdev->dev, "device has more than "
234					__stringify(MAX_UIO_MAPS)
235					" dynamic and fixed memory regions.\n");
236			break;
237		}
238		uiomem->memtype = UIO_MEM_PHYS;
 
239		uiomem->addr = DMEM_MAP_ERROR;
240		uiomem->size = pdata->dynamic_region_sizes[i];
241		++uiomem;
242	}
243
244	while (uiomem < &uioinfo->mem[MAX_UIO_MAPS]) {
245		uiomem->size = 0;
246		++uiomem;
247	}
248
249	/* This driver requires no hardware specific kernel code to handle
250	 * interrupts. Instead, the interrupt handler simply disables the
251	 * interrupt in the interrupt controller. User space is responsible
252	 * for performing hardware specific acknowledge and re-enabling of
253	 * the interrupt in the interrupt controller.
254	 *
255	 * Interrupt sharing is not supported.
256	 */
257
258	uioinfo->handler = uio_dmem_genirq_handler;
259	uioinfo->irqcontrol = uio_dmem_genirq_irqcontrol;
260	uioinfo->open = uio_dmem_genirq_open;
261	uioinfo->release = uio_dmem_genirq_release;
262	uioinfo->priv = priv;
263
264	/* Enable Runtime PM for this device:
265	 * The device starts in suspended state to allow the hardware to be
266	 * turned off by default. The Runtime PM bus code should power on the
267	 * hardware and enable clocks at open().
268	 */
269	pm_runtime_enable(&pdev->dev);
270
271	ret = uio_register_device(&pdev->dev, priv->uioinfo);
272	if (ret) {
273		dev_err(&pdev->dev, "unable to register uio device\n");
274		pm_runtime_disable(&pdev->dev);
275		goto bad1;
276	}
277
278	platform_set_drvdata(pdev, priv);
279	return 0;
280 bad1:
281	kfree(priv);
282 bad0:
283	/* kfree uioinfo for OF */
284	if (pdev->dev.of_node)
285		kfree(uioinfo);
286 bad2:
287	return ret;
288}
289
290static int uio_dmem_genirq_remove(struct platform_device *pdev)
291{
292	struct uio_dmem_genirq_platdata *priv = platform_get_drvdata(pdev);
293
294	uio_unregister_device(priv->uioinfo);
295	pm_runtime_disable(&pdev->dev);
296
297	priv->uioinfo->handler = NULL;
298	priv->uioinfo->irqcontrol = NULL;
299
300	/* kfree uioinfo for OF */
301	if (pdev->dev.of_node)
302		kfree(priv->uioinfo);
303
304	kfree(priv);
305	return 0;
306}
307
308static int uio_dmem_genirq_runtime_nop(struct device *dev)
309{
310	/* Runtime PM callback shared between ->runtime_suspend()
311	 * and ->runtime_resume(). Simply returns success.
312	 *
313	 * In this driver pm_runtime_get_sync() and pm_runtime_put_sync()
314	 * are used at open() and release() time. This allows the
315	 * Runtime PM code to turn off power to the device while the
316	 * device is unused, ie before open() and after release().
317	 *
318	 * This Runtime PM callback does not need to save or restore
319	 * any registers since user space is responsbile for hardware
320	 * register reinitialization after open().
321	 */
322	return 0;
323}
324
325static const struct dev_pm_ops uio_dmem_genirq_dev_pm_ops = {
326	.runtime_suspend = uio_dmem_genirq_runtime_nop,
327	.runtime_resume = uio_dmem_genirq_runtime_nop,
328};
329
330#ifdef CONFIG_OF
331static const struct of_device_id uio_of_genirq_match[] = {
332	{ /* empty for now */ },
333};
334MODULE_DEVICE_TABLE(of, uio_of_genirq_match);
335#endif
336
337static struct platform_driver uio_dmem_genirq = {
338	.probe = uio_dmem_genirq_probe,
339	.remove = uio_dmem_genirq_remove,
340	.driver = {
341		.name = DRIVER_NAME,
342		.pm = &uio_dmem_genirq_dev_pm_ops,
343		.of_match_table = of_match_ptr(uio_of_genirq_match),
344	},
345};
346
347module_platform_driver(uio_dmem_genirq);
348
349MODULE_AUTHOR("Damian Hobson-Garcia");
350MODULE_DESCRIPTION("Userspace I/O platform driver with dynamic memory.");
351MODULE_LICENSE("GPL v2");
352MODULE_ALIAS("platform:" DRIVER_NAME);