Version:  2.0.40 2.2.26 2.4.37 2.6.39 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15

Linux/drivers/uio/uio_dmem_genirq.c

  1 /*
  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 #define DMEM_MAP_ERROR (~0)
 33 
 34 struct uio_dmem_genirq_platdata {
 35         struct uio_info *uioinfo;
 36         spinlock_t lock;
 37         unsigned long flags;
 38         struct platform_device *pdev;
 39         unsigned int dmem_region_start;
 40         unsigned int num_dmem_regions;
 41         void *dmem_region_vaddr[MAX_UIO_MAPS];
 42         struct mutex alloc_lock;
 43         unsigned int refcnt;
 44 };
 45 
 46 static int uio_dmem_genirq_open(struct uio_info *info, struct inode *inode)
 47 {
 48         struct uio_dmem_genirq_platdata *priv = info->priv;
 49         struct uio_mem *uiomem;
 50         int ret = 0;
 51         int dmem_region = priv->dmem_region_start;
 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                                 (dma_addr_t *)&uiomem->addr, GFP_KERNEL);
 63                 if (!addr) {
 64                         uiomem->addr = DMEM_MAP_ERROR;
 65                 }
 66                 priv->dmem_region_vaddr[dmem_region++] = addr;
 67                 ++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 
 77 static 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;
 81         int dmem_region = priv->dmem_region_start;
 82 
 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                 if (priv->dmem_region_vaddr[dmem_region]) {
 95                         dma_free_coherent(&priv->pdev->dev, uiomem->size,
 96                                         priv->dmem_region_vaddr[dmem_region],
 97                                         uiomem->addr);
 98                 }
 99                 uiomem->addr = DMEM_MAP_ERROR;
100                 ++dmem_region;
101                 ++uiomem;
102         }
103 
104         mutex_unlock(&priv->alloc_lock);
105         return 0;
106 }
107 
108 static irqreturn_t uio_dmem_genirq_handler(int irq, struct uio_info *dev_info)
109 {
110         struct uio_dmem_genirq_platdata *priv = dev_info->priv;
111 
112         /* Just disable the interrupt in the interrupt controller, and
113          * remember the state so we can allow user space to enable it later.
114          */
115 
116         if (!test_and_set_bit(0, &priv->flags))
117                 disable_irq_nosync(irq);
118 
119         return IRQ_HANDLED;
120 }
121 
122 static int uio_dmem_genirq_irqcontrol(struct uio_info *dev_info, s32 irq_on)
123 {
124         struct uio_dmem_genirq_platdata *priv = dev_info->priv;
125         unsigned long flags;
126 
127         /* Allow user space to enable and disable the interrupt
128          * in the interrupt controller, but keep track of the
129          * state to prevent per-irq depth damage.
130          *
131          * Serialize this operation to support multiple tasks.
132          */
133 
134         spin_lock_irqsave(&priv->lock, flags);
135         if (irq_on) {
136                 if (test_and_clear_bit(0, &priv->flags))
137                         enable_irq(dev_info->irq);
138         } else {
139                 if (!test_and_set_bit(0, &priv->flags))
140                         disable_irq(dev_info->irq);
141         }
142         spin_unlock_irqrestore(&priv->lock, flags);
143 
144         return 0;
145 }
146 
147 static int uio_dmem_genirq_probe(struct platform_device *pdev)
148 {
149         struct uio_dmem_genirq_pdata *pdata = dev_get_platdata(&pdev->dev);
150         struct uio_info *uioinfo = &pdata->uioinfo;
151         struct uio_dmem_genirq_platdata *priv;
152         struct uio_mem *uiomem;
153         int ret = -EINVAL;
154         int i;
155 
156         if (pdev->dev.of_node) {
157                 int irq;
158 
159                 /* alloc uioinfo for one device */
160                 uioinfo = kzalloc(sizeof(*uioinfo), GFP_KERNEL);
161                 if (!uioinfo) {
162                         ret = -ENOMEM;
163                         dev_err(&pdev->dev, "unable to kmalloc\n");
164                         goto bad2;
165                 }
166                 uioinfo->name = pdev->dev.of_node->name;
167                 uioinfo->version = "devicetree";
168 
169                 /* Multiple IRQs are not supported */
170                 irq = platform_get_irq(pdev, 0);
171                 if (irq == -ENXIO)
172                         uioinfo->irq = UIO_IRQ_NONE;
173                 else
174                         uioinfo->irq = irq;
175         }
176 
177         if (!uioinfo || !uioinfo->name || !uioinfo->version) {
178                 dev_err(&pdev->dev, "missing platform_data\n");
179                 goto bad0;
180         }
181 
182         if (uioinfo->handler || uioinfo->irqcontrol ||
183             uioinfo->irq_flags & IRQF_SHARED) {
184                 dev_err(&pdev->dev, "interrupt configuration error\n");
185                 goto bad0;
186         }
187 
188         priv = kzalloc(sizeof(*priv), GFP_KERNEL);
189         if (!priv) {
190                 ret = -ENOMEM;
191                 dev_err(&pdev->dev, "unable to kmalloc\n");
192                 goto bad0;
193         }
194 
195         dma_set_coherent_mask(&pdev->dev, DMA_BIT_MASK(32));
196 
197         priv->uioinfo = uioinfo;
198         spin_lock_init(&priv->lock);
199         priv->flags = 0; /* interrupt is enabled to begin with */
200         priv->pdev = pdev;
201         mutex_init(&priv->alloc_lock);
202 
203         if (!uioinfo->irq) {
204                 ret = platform_get_irq(pdev, 0);
205                 if (ret < 0) {
206                         dev_err(&pdev->dev, "failed to get IRQ\n");
207                         goto bad0;
208                 }
209                 uioinfo->irq = ret;
210         }
211         uiomem = &uioinfo->mem[0];
212 
213         for (i = 0; i < pdev->num_resources; ++i) {
214                 struct resource *r = &pdev->resource[i];
215 
216                 if (r->flags != IORESOURCE_MEM)
217                         continue;
218 
219                 if (uiomem >= &uioinfo->mem[MAX_UIO_MAPS]) {
220                         dev_warn(&pdev->dev, "device has more than "
221                                         __stringify(MAX_UIO_MAPS)
222                                         " I/O memory resources.\n");
223                         break;
224                 }
225 
226                 uiomem->memtype = UIO_MEM_PHYS;
227                 uiomem->addr = r->start;
228                 uiomem->size = resource_size(r);
229                 ++uiomem;
230         }
231 
232         priv->dmem_region_start = i;
233         priv->num_dmem_regions = pdata->num_dynamic_regions;
234 
235         for (i = 0; i < pdata->num_dynamic_regions; ++i) {
236                 if (uiomem >= &uioinfo->mem[MAX_UIO_MAPS]) {
237                         dev_warn(&pdev->dev, "device has more than "
238                                         __stringify(MAX_UIO_MAPS)
239                                         " dynamic and fixed memory regions.\n");
240                         break;
241                 }
242                 uiomem->memtype = UIO_MEM_PHYS;
243                 uiomem->addr = DMEM_MAP_ERROR;
244                 uiomem->size = pdata->dynamic_region_sizes[i];
245                 ++uiomem;
246         }
247 
248         while (uiomem < &uioinfo->mem[MAX_UIO_MAPS]) {
249                 uiomem->size = 0;
250                 ++uiomem;
251         }
252 
253         /* This driver requires no hardware specific kernel code to handle
254          * interrupts. Instead, the interrupt handler simply disables the
255          * interrupt in the interrupt controller. User space is responsible
256          * for performing hardware specific acknowledge and re-enabling of
257          * the interrupt in the interrupt controller.
258          *
259          * Interrupt sharing is not supported.
260          */
261 
262         uioinfo->handler = uio_dmem_genirq_handler;
263         uioinfo->irqcontrol = uio_dmem_genirq_irqcontrol;
264         uioinfo->open = uio_dmem_genirq_open;
265         uioinfo->release = uio_dmem_genirq_release;
266         uioinfo->priv = priv;
267 
268         /* Enable Runtime PM for this device:
269          * The device starts in suspended state to allow the hardware to be
270          * turned off by default. The Runtime PM bus code should power on the
271          * hardware and enable clocks at open().
272          */
273         pm_runtime_enable(&pdev->dev);
274 
275         ret = uio_register_device(&pdev->dev, priv->uioinfo);
276         if (ret) {
277                 dev_err(&pdev->dev, "unable to register uio device\n");
278                 goto bad1;
279         }
280 
281         platform_set_drvdata(pdev, priv);
282         return 0;
283  bad1:
284         kfree(priv);
285         pm_runtime_disable(&pdev->dev);
286  bad0:
287         /* kfree uioinfo for OF */
288         if (pdev->dev.of_node)
289                 kfree(uioinfo);
290  bad2:
291         return ret;
292 }
293 
294 static int uio_dmem_genirq_remove(struct platform_device *pdev)
295 {
296         struct uio_dmem_genirq_platdata *priv = platform_get_drvdata(pdev);
297 
298         uio_unregister_device(priv->uioinfo);
299         pm_runtime_disable(&pdev->dev);
300 
301         priv->uioinfo->handler = NULL;
302         priv->uioinfo->irqcontrol = NULL;
303 
304         /* kfree uioinfo for OF */
305         if (pdev->dev.of_node)
306                 kfree(priv->uioinfo);
307 
308         kfree(priv);
309         return 0;
310 }
311 
312 static int uio_dmem_genirq_runtime_nop(struct device *dev)
313 {
314         /* Runtime PM callback shared between ->runtime_suspend()
315          * and ->runtime_resume(). Simply returns success.
316          *
317          * In this driver pm_runtime_get_sync() and pm_runtime_put_sync()
318          * are used at open() and release() time. This allows the
319          * Runtime PM code to turn off power to the device while the
320          * device is unused, ie before open() and after release().
321          *
322          * This Runtime PM callback does not need to save or restore
323          * any registers since user space is responsbile for hardware
324          * register reinitialization after open().
325          */
326         return 0;
327 }
328 
329 static const struct dev_pm_ops uio_dmem_genirq_dev_pm_ops = {
330         .runtime_suspend = uio_dmem_genirq_runtime_nop,
331         .runtime_resume = uio_dmem_genirq_runtime_nop,
332 };
333 
334 #ifdef CONFIG_OF
335 static const struct of_device_id uio_of_genirq_match[] = {
336         { /* empty for now */ },
337 };
338 MODULE_DEVICE_TABLE(of, uio_of_genirq_match);
339 #endif
340 
341 static 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 = of_match_ptr(uio_of_genirq_match),
349         },
350 };
351 
352 module_platform_driver(uio_dmem_genirq);
353 
354 MODULE_AUTHOR("Damian Hobson-Garcia");
355 MODULE_DESCRIPTION("Userspace I/O platform driver with dynamic memory.");
356 MODULE_LICENSE("GPL v2");
357 MODULE_ALIAS("platform:" DRIVER_NAME);
358 

This page was automatically generated by LXR 0.3.1 (source).  •  Linux is a registered trademark of Linus Torvalds  •  Contact us