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d2912cb1 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
c767db0a MD |
2 | /* |
3 | * drivers/uio/uio_pdrv_genirq.c | |
4 | * | |
5 | * Userspace I/O platform driver with generic IRQ handling code. | |
6 | * | |
7 | * Copyright (C) 2008 Magnus Damm | |
8 | * | |
9 | * Based on uio_pdrv.c by Uwe Kleine-Koenig, | |
10 | * Copyright (C) 2008 by Digi International Inc. | |
11 | * All rights reserved. | |
c767db0a MD |
12 | */ |
13 | ||
14 | #include <linux/platform_device.h> | |
15 | #include <linux/uio_driver.h> | |
16 | #include <linux/spinlock.h> | |
17 | #include <linux/bitops.h> | |
2949ead4 | 18 | #include <linux/module.h> |
c767db0a MD |
19 | #include <linux/interrupt.h> |
20 | #include <linux/stringify.h> | |
af76756e | 21 | #include <linux/pm_runtime.h> |
5a0e3ad6 | 22 | #include <linux/slab.h> |
415abcdf | 23 | #include <linux/irq.h> |
c767db0a | 24 | |
27760f86 HK |
25 | #include <linux/of.h> |
26 | #include <linux/of_platform.h> | |
27 | #include <linux/of_address.h> | |
28 | ||
c767db0a MD |
29 | #define DRIVER_NAME "uio_pdrv_genirq" |
30 | ||
31 | struct uio_pdrv_genirq_platdata { | |
32 | struct uio_info *uioinfo; | |
33 | spinlock_t lock; | |
34 | unsigned long flags; | |
af76756e | 35 | struct platform_device *pdev; |
c767db0a MD |
36 | }; |
37 | ||
34cb2752 VD |
38 | /* Bits in uio_pdrv_genirq_platdata.flags */ |
39 | enum { | |
40 | UIO_IRQ_DISABLED = 0, | |
41 | }; | |
42 | ||
af76756e MD |
43 | static int uio_pdrv_genirq_open(struct uio_info *info, struct inode *inode) |
44 | { | |
45 | struct uio_pdrv_genirq_platdata *priv = info->priv; | |
46 | ||
47 | /* Wait until the Runtime PM code has woken up the device */ | |
48 | pm_runtime_get_sync(&priv->pdev->dev); | |
49 | return 0; | |
50 | } | |
51 | ||
52 | static int uio_pdrv_genirq_release(struct uio_info *info, struct inode *inode) | |
53 | { | |
54 | struct uio_pdrv_genirq_platdata *priv = info->priv; | |
55 | ||
56 | /* Tell the Runtime PM code that the device has become idle */ | |
57 | pm_runtime_put_sync(&priv->pdev->dev); | |
58 | return 0; | |
59 | } | |
60 | ||
c767db0a MD |
61 | static irqreturn_t uio_pdrv_genirq_handler(int irq, struct uio_info *dev_info) |
62 | { | |
63 | struct uio_pdrv_genirq_platdata *priv = dev_info->priv; | |
64 | ||
65 | /* Just disable the interrupt in the interrupt controller, and | |
66 | * remember the state so we can allow user space to enable it later. | |
67 | */ | |
68 | ||
34cb2752 VD |
69 | spin_lock(&priv->lock); |
70 | if (!__test_and_set_bit(UIO_IRQ_DISABLED, &priv->flags)) | |
c767db0a | 71 | disable_irq_nosync(irq); |
34cb2752 | 72 | spin_unlock(&priv->lock); |
c767db0a MD |
73 | |
74 | return IRQ_HANDLED; | |
75 | } | |
76 | ||
77 | static int uio_pdrv_genirq_irqcontrol(struct uio_info *dev_info, s32 irq_on) | |
78 | { | |
79 | struct uio_pdrv_genirq_platdata *priv = dev_info->priv; | |
80 | unsigned long flags; | |
81 | ||
82 | /* Allow user space to enable and disable the interrupt | |
83 | * in the interrupt controller, but keep track of the | |
84 | * state to prevent per-irq depth damage. | |
85 | * | |
34cb2752 VD |
86 | * Serialize this operation to support multiple tasks and concurrency |
87 | * with irq handler on SMP systems. | |
c767db0a MD |
88 | */ |
89 | ||
90 | spin_lock_irqsave(&priv->lock, flags); | |
91 | if (irq_on) { | |
34cb2752 | 92 | if (__test_and_clear_bit(UIO_IRQ_DISABLED, &priv->flags)) |
c767db0a MD |
93 | enable_irq(dev_info->irq); |
94 | } else { | |
34cb2752 VD |
95 | if (!__test_and_set_bit(UIO_IRQ_DISABLED, &priv->flags)) |
96 | disable_irq_nosync(dev_info->irq); | |
c767db0a MD |
97 | } |
98 | spin_unlock_irqrestore(&priv->lock, flags); | |
99 | ||
100 | return 0; | |
101 | } | |
102 | ||
eff1dd87 AA |
103 | static void uio_pdrv_genirq_cleanup(void *data) |
104 | { | |
105 | struct device *dev = data; | |
106 | ||
107 | pm_runtime_disable(dev); | |
108 | } | |
109 | ||
c767db0a MD |
110 | static int uio_pdrv_genirq_probe(struct platform_device *pdev) |
111 | { | |
08cb2e21 | 112 | struct uio_info *uioinfo = dev_get_platdata(&pdev->dev); |
b0297622 | 113 | struct device_node *node = pdev->dev.of_node; |
c767db0a MD |
114 | struct uio_pdrv_genirq_platdata *priv; |
115 | struct uio_mem *uiomem; | |
116 | int ret = -EINVAL; | |
117 | int i; | |
118 | ||
b0297622 DM |
119 | if (node) { |
120 | const char *name; | |
121 | ||
27760f86 | 122 | /* alloc uioinfo for one device */ |
e6789cd3 MS |
123 | uioinfo = devm_kzalloc(&pdev->dev, sizeof(*uioinfo), |
124 | GFP_KERNEL); | |
27760f86 | 125 | if (!uioinfo) { |
27760f86 | 126 | dev_err(&pdev->dev, "unable to kmalloc\n"); |
e6789cd3 | 127 | return -ENOMEM; |
27760f86 | 128 | } |
b0297622 DM |
129 | |
130 | if (!of_property_read_string(node, "linux,uio-name", &name)) | |
131 | uioinfo->name = devm_kstrdup(&pdev->dev, name, GFP_KERNEL); | |
132 | else | |
133 | uioinfo->name = devm_kasprintf(&pdev->dev, GFP_KERNEL, | |
134 | "%pOFn", node); | |
135 | ||
27760f86 | 136 | uioinfo->version = "devicetree"; |
27760f86 | 137 | /* Multiple IRQs are not supported */ |
27760f86 HK |
138 | } |
139 | ||
c767db0a MD |
140 | if (!uioinfo || !uioinfo->name || !uioinfo->version) { |
141 | dev_err(&pdev->dev, "missing platform_data\n"); | |
e6789cd3 | 142 | return ret; |
c767db0a MD |
143 | } |
144 | ||
e543ae89 MF |
145 | if (uioinfo->handler || uioinfo->irqcontrol || |
146 | uioinfo->irq_flags & IRQF_SHARED) { | |
c767db0a | 147 | dev_err(&pdev->dev, "interrupt configuration error\n"); |
e6789cd3 | 148 | return ret; |
c767db0a MD |
149 | } |
150 | ||
e6789cd3 | 151 | priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); |
c767db0a | 152 | if (!priv) { |
c767db0a | 153 | dev_err(&pdev->dev, "unable to kmalloc\n"); |
e6789cd3 | 154 | return -ENOMEM; |
c767db0a MD |
155 | } |
156 | ||
157 | priv->uioinfo = uioinfo; | |
158 | spin_lock_init(&priv->lock); | |
159 | priv->flags = 0; /* interrupt is enabled to begin with */ | |
af76756e | 160 | priv->pdev = pdev; |
c767db0a | 161 | |
94ca629e | 162 | if (!uioinfo->irq) { |
324ac45f | 163 | ret = platform_get_irq_optional(pdev, 0); |
e3a3c3a2 | 164 | uioinfo->irq = ret; |
bf12fdf0 | 165 | if (ret == -ENXIO) |
e3a3c3a2 | 166 | uioinfo->irq = UIO_IRQ_NONE; |
34bc4f46 OR |
167 | else if (ret == -EPROBE_DEFER) |
168 | return ret; | |
e3a3c3a2 | 169 | else if (ret < 0) { |
94ca629e | 170 | dev_err(&pdev->dev, "failed to get IRQ\n"); |
e6789cd3 | 171 | return ret; |
94ca629e | 172 | } |
94ca629e | 173 | } |
e3a3c3a2 | 174 | |
415abcdf TJ |
175 | if (uioinfo->irq) { |
176 | struct irq_data *irq_data = irq_get_irq_data(uioinfo->irq); | |
177 | ||
178 | /* | |
179 | * If a level interrupt, dont do lazy disable. Otherwise the | |
180 | * irq will fire again since clearing of the actual cause, on | |
181 | * device level, is done in userspace | |
182 | * irqd_is_level_type() isn't used since isn't valid until | |
183 | * irq is configured. | |
184 | */ | |
185 | if (irq_data && | |
186 | irqd_get_trigger_type(irq_data) & IRQ_TYPE_LEVEL_MASK) { | |
187 | dev_dbg(&pdev->dev, "disable lazy unmask\n"); | |
188 | irq_set_status_flags(uioinfo->irq, IRQ_DISABLE_UNLAZY); | |
189 | } | |
190 | } | |
191 | ||
c767db0a MD |
192 | uiomem = &uioinfo->mem[0]; |
193 | ||
194 | for (i = 0; i < pdev->num_resources; ++i) { | |
195 | struct resource *r = &pdev->resource[i]; | |
196 | ||
197 | if (r->flags != IORESOURCE_MEM) | |
198 | continue; | |
199 | ||
200 | if (uiomem >= &uioinfo->mem[MAX_UIO_MAPS]) { | |
201 | dev_warn(&pdev->dev, "device has more than " | |
202 | __stringify(MAX_UIO_MAPS) | |
203 | " I/O memory resources.\n"); | |
204 | break; | |
205 | } | |
206 | ||
207 | uiomem->memtype = UIO_MEM_PHYS; | |
7aca462b EH |
208 | uiomem->addr = r->start & PAGE_MASK; |
209 | uiomem->offs = r->start & ~PAGE_MASK; | |
210 | uiomem->size = (uiomem->offs + resource_size(r) | |
211 | + PAGE_SIZE - 1) & PAGE_MASK; | |
ecd43c0d | 212 | uiomem->name = r->name; |
c767db0a MD |
213 | ++uiomem; |
214 | } | |
215 | ||
216 | while (uiomem < &uioinfo->mem[MAX_UIO_MAPS]) { | |
217 | uiomem->size = 0; | |
218 | ++uiomem; | |
219 | } | |
220 | ||
221 | /* This driver requires no hardware specific kernel code to handle | |
222 | * interrupts. Instead, the interrupt handler simply disables the | |
223 | * interrupt in the interrupt controller. User space is responsible | |
224 | * for performing hardware specific acknowledge and re-enabling of | |
225 | * the interrupt in the interrupt controller. | |
226 | * | |
227 | * Interrupt sharing is not supported. | |
228 | */ | |
229 | ||
c767db0a MD |
230 | uioinfo->handler = uio_pdrv_genirq_handler; |
231 | uioinfo->irqcontrol = uio_pdrv_genirq_irqcontrol; | |
af76756e MD |
232 | uioinfo->open = uio_pdrv_genirq_open; |
233 | uioinfo->release = uio_pdrv_genirq_release; | |
c767db0a MD |
234 | uioinfo->priv = priv; |
235 | ||
af76756e MD |
236 | /* Enable Runtime PM for this device: |
237 | * The device starts in suspended state to allow the hardware to be | |
238 | * turned off by default. The Runtime PM bus code should power on the | |
239 | * hardware and enable clocks at open(). | |
240 | */ | |
241 | pm_runtime_enable(&pdev->dev); | |
242 | ||
eff1dd87 AA |
243 | ret = devm_add_action_or_reset(&pdev->dev, uio_pdrv_genirq_cleanup, |
244 | &pdev->dev); | |
245 | if (ret) | |
e6789cd3 | 246 | return ret; |
c767db0a | 247 | |
eff1dd87 AA |
248 | ret = devm_uio_register_device(&pdev->dev, priv->uioinfo); |
249 | if (ret) | |
250 | dev_err(&pdev->dev, "unable to register uio device\n"); | |
47296b19 | 251 | |
eff1dd87 | 252 | return ret; |
c767db0a MD |
253 | } |
254 | ||
af76756e MD |
255 | static int uio_pdrv_genirq_runtime_nop(struct device *dev) |
256 | { | |
257 | /* Runtime PM callback shared between ->runtime_suspend() | |
258 | * and ->runtime_resume(). Simply returns success. | |
259 | * | |
260 | * In this driver pm_runtime_get_sync() and pm_runtime_put_sync() | |
261 | * are used at open() and release() time. This allows the | |
262 | * Runtime PM code to turn off power to the device while the | |
263 | * device is unused, ie before open() and after release(). | |
264 | * | |
265 | * This Runtime PM callback does not need to save or restore | |
266 | * any registers since user space is responsbile for hardware | |
267 | * register reinitialization after open(). | |
268 | */ | |
269 | return 0; | |
270 | } | |
271 | ||
47145210 | 272 | static const struct dev_pm_ops uio_pdrv_genirq_dev_pm_ops = { |
af76756e MD |
273 | .runtime_suspend = uio_pdrv_genirq_runtime_nop, |
274 | .runtime_resume = uio_pdrv_genirq_runtime_nop, | |
275 | }; | |
276 | ||
27760f86 | 277 | #ifdef CONFIG_OF |
05c3e0bb PM |
278 | static struct of_device_id uio_of_genirq_match[] = { |
279 | { /* This is filled with module_parm */ }, | |
280 | { /* Sentinel */ }, | |
27760f86 HK |
281 | }; |
282 | MODULE_DEVICE_TABLE(of, uio_of_genirq_match); | |
05c3e0bb PM |
283 | module_param_string(of_id, uio_of_genirq_match[0].compatible, 128, 0); |
284 | MODULE_PARM_DESC(of_id, "Openfirmware id of the device to be handled by uio"); | |
27760f86 HK |
285 | #endif |
286 | ||
c767db0a MD |
287 | static struct platform_driver uio_pdrv_genirq = { |
288 | .probe = uio_pdrv_genirq_probe, | |
c767db0a MD |
289 | .driver = { |
290 | .name = DRIVER_NAME, | |
af76756e | 291 | .pm = &uio_pdrv_genirq_dev_pm_ops, |
cee4fbd6 | 292 | .of_match_table = of_match_ptr(uio_of_genirq_match), |
c767db0a MD |
293 | }, |
294 | }; | |
295 | ||
11e3123d | 296 | module_platform_driver(uio_pdrv_genirq); |
c767db0a MD |
297 | |
298 | MODULE_AUTHOR("Magnus Damm"); | |
299 | MODULE_DESCRIPTION("Userspace I/O platform driver with generic IRQ handling"); | |
300 | MODULE_LICENSE("GPL v2"); | |
301 | MODULE_ALIAS("platform:" DRIVER_NAME); |