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0a0c3b5a DHG |
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 | ||
33 | struct 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; | |
24fce61b | 40 | void *dmem_region_vaddr[MAX_UIO_MAPS]; |
0a0c3b5a DHG |
41 | struct mutex alloc_lock; |
42 | unsigned int refcnt; | |
43 | }; | |
44 | ||
45 | static 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; | |
24fce61b | 50 | int dmem_region = priv->dmem_region_start; |
0a0c3b5a DHG |
51 | |
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 | } | |
24fce61b | 66 | priv->dmem_region_vaddr[dmem_region++] = addr; |
0a0c3b5a DHG |
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; | |
24fce61b | 81 | int dmem_region = priv->dmem_region_start; |
0a0c3b5a DHG |
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 | ||
95 | dma_free_coherent(&priv->pdev->dev, uiomem->size, | |
24fce61b DHG |
96 | priv->dmem_region_vaddr[dmem_region++], |
97 | uiomem->addr); | |
0a0c3b5a DHG |
98 | uiomem->addr = DMA_ERROR_CODE; |
99 | ++uiomem; | |
100 | } | |
101 | ||
102 | mutex_unlock(&priv->alloc_lock); | |
103 | return 0; | |
104 | } | |
105 | ||
106 | static 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 | ||
120 | static 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 | ||
145 | static 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 | ||
292 | static 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 | ||
310 | static 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 | ||
327 | static 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 | |
333 | static const struct of_device_id uio_of_genirq_match[] = { | |
334 | { /* empty for now */ }, | |
335 | }; | |
336 | MODULE_DEVICE_TABLE(of, uio_of_genirq_match); | |
337 | #else | |
338 | # define uio_of_genirq_match NULL | |
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 = 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); |