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d2912cb1 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
0a0c3b5a DHG |
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 | |
0a0c3b5a DHG |
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" | |
87c4d1a7 | 29 | #define DMEM_MAP_ERROR (~0) |
0a0c3b5a DHG |
30 | |
31 | struct 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; | |
24fce61b | 38 | void *dmem_region_vaddr[MAX_UIO_MAPS]; |
0a0c3b5a DHG |
39 | struct mutex alloc_lock; |
40 | unsigned int refcnt; | |
41 | }; | |
42 | ||
43 | static 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; | |
24fce61b | 48 | int dmem_region = priv->dmem_region_start; |
0a0c3b5a DHG |
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) { | |
87c4d1a7 | 61 | uiomem->addr = DMEM_MAP_ERROR; |
0a0c3b5a | 62 | } |
24fce61b | 63 | priv->dmem_region_vaddr[dmem_region++] = addr; |
0a0c3b5a DHG |
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 | ||
74 | static 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; | |
24fce61b | 78 | int dmem_region = priv->dmem_region_start; |
0a0c3b5a DHG |
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; | |
439926c8 DHG |
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 | } | |
87c4d1a7 | 96 | uiomem->addr = DMEM_MAP_ERROR; |
439926c8 | 97 | ++dmem_region; |
0a0c3b5a DHG |
98 | ++uiomem; |
99 | } | |
100 | ||
101 | mutex_unlock(&priv->alloc_lock); | |
102 | return 0; | |
103 | } | |
104 | ||
105 | static 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 | ||
119 | static 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 | ||
144 | static int uio_dmem_genirq_probe(struct platform_device *pdev) | |
145 | { | |
31f52213 | 146 | struct uio_dmem_genirq_pdata *pdata = dev_get_platdata(&pdev->dev); |
0a0c3b5a DHG |
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 | ||
d5185c4e | 153 | if (pdev->dev.of_node) { |
0a0c3b5a DHG |
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 | } | |
52e2dc2c RH |
163 | uioinfo->name = devm_kasprintf(&pdev->dev, GFP_KERNEL, "%pOFn", |
164 | pdev->dev.of_node); | |
0a0c3b5a DHG |
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); | |
75080370 | 203 | if (ret < 0) |
ca3c61f3 | 204 | goto bad1; |
0a0c3b5a DHG |
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 | ||
4d31a258 | 228 | priv->dmem_region_start = uiomem - &uioinfo->mem[0]; |
0a0c3b5a DHG |
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; | |
87c4d1a7 | 239 | uiomem->addr = DMEM_MAP_ERROR; |
0a0c3b5a DHG |
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"); | |
ca3c61f3 | 274 | pm_runtime_disable(&pdev->dev); |
0a0c3b5a DHG |
275 | goto bad1; |
276 | } | |
277 | ||
278 | platform_set_drvdata(pdev, priv); | |
279 | return 0; | |
280 | bad1: | |
281 | kfree(priv); | |
0a0c3b5a DHG |
282 | bad0: |
283 | /* kfree uioinfo for OF */ | |
284 | if (pdev->dev.of_node) | |
285 | kfree(uioinfo); | |
286 | bad2: | |
287 | return ret; | |
288 | } | |
289 | ||
290 | static 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 | ||
308 | static 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 | ||
325 | static 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 | |
331 | static const struct of_device_id uio_of_genirq_match[] = { | |
332 | { /* empty for now */ }, | |
333 | }; | |
334 | MODULE_DEVICE_TABLE(of, uio_of_genirq_match); | |
0a0c3b5a DHG |
335 | #endif |
336 | ||
337 | static struct platform_driver uio_dmem_genirq = { | |
338 | .probe = uio_dmem_genirq_probe, | |
339 | .remove = uio_dmem_genirq_remove, | |
340 | .driver = { | |
341 | .name = DRIVER_NAME, | |
0a0c3b5a | 342 | .pm = &uio_dmem_genirq_dev_pm_ops, |
07779711 | 343 | .of_match_table = of_match_ptr(uio_of_genirq_match), |
0a0c3b5a DHG |
344 | }, |
345 | }; | |
346 | ||
347 | module_platform_driver(uio_dmem_genirq); | |
348 | ||
349 | MODULE_AUTHOR("Damian Hobson-Garcia"); | |
350 | MODULE_DESCRIPTION("Userspace I/O platform driver with dynamic memory."); | |
351 | MODULE_LICENSE("GPL v2"); | |
352 | MODULE_ALIAS("platform:" DRIVER_NAME); |