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