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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 = pdev->dev.platform_data; |
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 | #else |
340 | # define uio_of_genirq_match NULL |
341 | #endif |
342 | |
343 | static struct platform_driver uio_dmem_genirq = { |
344 | .probe = uio_dmem_genirq_probe, |
345 | .remove = uio_dmem_genirq_remove, |
346 | .driver = { |
347 | .name = DRIVER_NAME, |
348 | .owner = THIS_MODULE, |
349 | .pm = &uio_dmem_genirq_dev_pm_ops, |
350 | .of_match_table = uio_of_genirq_match, |
351 | }, |
352 | }; |
353 | |
354 | module_platform_driver(uio_dmem_genirq); |
355 | |
356 | MODULE_AUTHOR("Damian Hobson-Garcia"); |
357 | MODULE_DESCRIPTION("Userspace I/O platform driver with dynamic memory."); |
358 | MODULE_LICENSE("GPL v2"); |
359 | MODULE_ALIAS("platform:" DRIVER_NAME); |
360 |
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