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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> |
c767db0a | 23 | |
27760f86 HK |
24 | #include <linux/of.h> |
25 | #include <linux/of_platform.h> | |
26 | #include <linux/of_address.h> | |
27 | ||
c767db0a MD |
28 | #define DRIVER_NAME "uio_pdrv_genirq" |
29 | ||
30 | struct uio_pdrv_genirq_platdata { | |
31 | struct uio_info *uioinfo; | |
32 | spinlock_t lock; | |
33 | unsigned long flags; | |
af76756e | 34 | struct platform_device *pdev; |
c767db0a MD |
35 | }; |
36 | ||
34cb2752 VD |
37 | /* Bits in uio_pdrv_genirq_platdata.flags */ |
38 | enum { | |
39 | UIO_IRQ_DISABLED = 0, | |
40 | }; | |
41 | ||
af76756e MD |
42 | static int uio_pdrv_genirq_open(struct uio_info *info, struct inode *inode) |
43 | { | |
44 | struct uio_pdrv_genirq_platdata *priv = info->priv; | |
45 | ||
46 | /* Wait until the Runtime PM code has woken up the device */ | |
47 | pm_runtime_get_sync(&priv->pdev->dev); | |
48 | return 0; | |
49 | } | |
50 | ||
51 | static int uio_pdrv_genirq_release(struct uio_info *info, struct inode *inode) | |
52 | { | |
53 | struct uio_pdrv_genirq_platdata *priv = info->priv; | |
54 | ||
55 | /* Tell the Runtime PM code that the device has become idle */ | |
56 | pm_runtime_put_sync(&priv->pdev->dev); | |
57 | return 0; | |
58 | } | |
59 | ||
c767db0a MD |
60 | static irqreturn_t uio_pdrv_genirq_handler(int irq, struct uio_info *dev_info) |
61 | { | |
62 | struct uio_pdrv_genirq_platdata *priv = dev_info->priv; | |
63 | ||
64 | /* Just disable the interrupt in the interrupt controller, and | |
65 | * remember the state so we can allow user space to enable it later. | |
66 | */ | |
67 | ||
34cb2752 VD |
68 | spin_lock(&priv->lock); |
69 | if (!__test_and_set_bit(UIO_IRQ_DISABLED, &priv->flags)) | |
c767db0a | 70 | disable_irq_nosync(irq); |
34cb2752 | 71 | spin_unlock(&priv->lock); |
c767db0a MD |
72 | |
73 | return IRQ_HANDLED; | |
74 | } | |
75 | ||
76 | static int uio_pdrv_genirq_irqcontrol(struct uio_info *dev_info, s32 irq_on) | |
77 | { | |
78 | struct uio_pdrv_genirq_platdata *priv = dev_info->priv; | |
79 | unsigned long flags; | |
80 | ||
81 | /* Allow user space to enable and disable the interrupt | |
82 | * in the interrupt controller, but keep track of the | |
83 | * state to prevent per-irq depth damage. | |
84 | * | |
34cb2752 VD |
85 | * Serialize this operation to support multiple tasks and concurrency |
86 | * with irq handler on SMP systems. | |
c767db0a MD |
87 | */ |
88 | ||
89 | spin_lock_irqsave(&priv->lock, flags); | |
90 | if (irq_on) { | |
34cb2752 | 91 | if (__test_and_clear_bit(UIO_IRQ_DISABLED, &priv->flags)) |
c767db0a MD |
92 | enable_irq(dev_info->irq); |
93 | } else { | |
34cb2752 VD |
94 | if (!__test_and_set_bit(UIO_IRQ_DISABLED, &priv->flags)) |
95 | disable_irq_nosync(dev_info->irq); | |
c767db0a MD |
96 | } |
97 | spin_unlock_irqrestore(&priv->lock, flags); | |
98 | ||
99 | return 0; | |
100 | } | |
101 | ||
eff1dd87 AA |
102 | static void uio_pdrv_genirq_cleanup(void *data) |
103 | { | |
104 | struct device *dev = data; | |
105 | ||
106 | pm_runtime_disable(dev); | |
107 | } | |
108 | ||
c767db0a MD |
109 | static int uio_pdrv_genirq_probe(struct platform_device *pdev) |
110 | { | |
08cb2e21 | 111 | struct uio_info *uioinfo = dev_get_platdata(&pdev->dev); |
b0297622 | 112 | struct device_node *node = pdev->dev.of_node; |
c767db0a MD |
113 | struct uio_pdrv_genirq_platdata *priv; |
114 | struct uio_mem *uiomem; | |
115 | int ret = -EINVAL; | |
116 | int i; | |
117 | ||
b0297622 DM |
118 | if (node) { |
119 | const char *name; | |
120 | ||
27760f86 | 121 | /* alloc uioinfo for one device */ |
e6789cd3 MS |
122 | uioinfo = devm_kzalloc(&pdev->dev, sizeof(*uioinfo), |
123 | GFP_KERNEL); | |
27760f86 | 124 | if (!uioinfo) { |
27760f86 | 125 | dev_err(&pdev->dev, "unable to kmalloc\n"); |
e6789cd3 | 126 | return -ENOMEM; |
27760f86 | 127 | } |
b0297622 DM |
128 | |
129 | if (!of_property_read_string(node, "linux,uio-name", &name)) | |
130 | uioinfo->name = devm_kstrdup(&pdev->dev, name, GFP_KERNEL); | |
131 | else | |
132 | uioinfo->name = devm_kasprintf(&pdev->dev, GFP_KERNEL, | |
133 | "%pOFn", node); | |
134 | ||
27760f86 | 135 | uioinfo->version = "devicetree"; |
27760f86 | 136 | /* Multiple IRQs are not supported */ |
27760f86 HK |
137 | } |
138 | ||
c767db0a MD |
139 | if (!uioinfo || !uioinfo->name || !uioinfo->version) { |
140 | dev_err(&pdev->dev, "missing platform_data\n"); | |
e6789cd3 | 141 | return ret; |
c767db0a MD |
142 | } |
143 | ||
e543ae89 MF |
144 | if (uioinfo->handler || uioinfo->irqcontrol || |
145 | uioinfo->irq_flags & IRQF_SHARED) { | |
c767db0a | 146 | dev_err(&pdev->dev, "interrupt configuration error\n"); |
e6789cd3 | 147 | return ret; |
c767db0a MD |
148 | } |
149 | ||
e6789cd3 | 150 | priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); |
c767db0a | 151 | if (!priv) { |
c767db0a | 152 | dev_err(&pdev->dev, "unable to kmalloc\n"); |
e6789cd3 | 153 | return -ENOMEM; |
c767db0a MD |
154 | } |
155 | ||
156 | priv->uioinfo = uioinfo; | |
157 | spin_lock_init(&priv->lock); | |
158 | priv->flags = 0; /* interrupt is enabled to begin with */ | |
af76756e | 159 | priv->pdev = pdev; |
c767db0a | 160 | |
94ca629e BS |
161 | if (!uioinfo->irq) { |
162 | ret = platform_get_irq(pdev, 0); | |
e3a3c3a2 PM |
163 | uioinfo->irq = ret; |
164 | if (ret == -ENXIO && pdev->dev.of_node) | |
165 | uioinfo->irq = UIO_IRQ_NONE; | |
34bc4f46 OR |
166 | else if (ret == -EPROBE_DEFER) |
167 | return ret; | |
e3a3c3a2 | 168 | else if (ret < 0) { |
94ca629e | 169 | dev_err(&pdev->dev, "failed to get IRQ\n"); |
e6789cd3 | 170 | return ret; |
94ca629e | 171 | } |
94ca629e | 172 | } |
e3a3c3a2 | 173 | |
c767db0a MD |
174 | uiomem = &uioinfo->mem[0]; |
175 | ||
176 | for (i = 0; i < pdev->num_resources; ++i) { | |
177 | struct resource *r = &pdev->resource[i]; | |
178 | ||
179 | if (r->flags != IORESOURCE_MEM) | |
180 | continue; | |
181 | ||
182 | if (uiomem >= &uioinfo->mem[MAX_UIO_MAPS]) { | |
183 | dev_warn(&pdev->dev, "device has more than " | |
184 | __stringify(MAX_UIO_MAPS) | |
185 | " I/O memory resources.\n"); | |
186 | break; | |
187 | } | |
188 | ||
189 | uiomem->memtype = UIO_MEM_PHYS; | |
190 | uiomem->addr = r->start; | |
28f65c11 | 191 | uiomem->size = resource_size(r); |
ecd43c0d | 192 | uiomem->name = r->name; |
c767db0a MD |
193 | ++uiomem; |
194 | } | |
195 | ||
196 | while (uiomem < &uioinfo->mem[MAX_UIO_MAPS]) { | |
197 | uiomem->size = 0; | |
198 | ++uiomem; | |
199 | } | |
200 | ||
201 | /* This driver requires no hardware specific kernel code to handle | |
202 | * interrupts. Instead, the interrupt handler simply disables the | |
203 | * interrupt in the interrupt controller. User space is responsible | |
204 | * for performing hardware specific acknowledge and re-enabling of | |
205 | * the interrupt in the interrupt controller. | |
206 | * | |
207 | * Interrupt sharing is not supported. | |
208 | */ | |
209 | ||
c767db0a MD |
210 | uioinfo->handler = uio_pdrv_genirq_handler; |
211 | uioinfo->irqcontrol = uio_pdrv_genirq_irqcontrol; | |
af76756e MD |
212 | uioinfo->open = uio_pdrv_genirq_open; |
213 | uioinfo->release = uio_pdrv_genirq_release; | |
c767db0a MD |
214 | uioinfo->priv = priv; |
215 | ||
af76756e MD |
216 | /* Enable Runtime PM for this device: |
217 | * The device starts in suspended state to allow the hardware to be | |
218 | * turned off by default. The Runtime PM bus code should power on the | |
219 | * hardware and enable clocks at open(). | |
220 | */ | |
221 | pm_runtime_enable(&pdev->dev); | |
222 | ||
eff1dd87 AA |
223 | ret = devm_add_action_or_reset(&pdev->dev, uio_pdrv_genirq_cleanup, |
224 | &pdev->dev); | |
225 | if (ret) | |
e6789cd3 | 226 | return ret; |
c767db0a | 227 | |
eff1dd87 AA |
228 | ret = devm_uio_register_device(&pdev->dev, priv->uioinfo); |
229 | if (ret) | |
230 | dev_err(&pdev->dev, "unable to register uio device\n"); | |
47296b19 | 231 | |
eff1dd87 | 232 | return ret; |
c767db0a MD |
233 | } |
234 | ||
af76756e MD |
235 | static int uio_pdrv_genirq_runtime_nop(struct device *dev) |
236 | { | |
237 | /* Runtime PM callback shared between ->runtime_suspend() | |
238 | * and ->runtime_resume(). Simply returns success. | |
239 | * | |
240 | * In this driver pm_runtime_get_sync() and pm_runtime_put_sync() | |
241 | * are used at open() and release() time. This allows the | |
242 | * Runtime PM code to turn off power to the device while the | |
243 | * device is unused, ie before open() and after release(). | |
244 | * | |
245 | * This Runtime PM callback does not need to save or restore | |
246 | * any registers since user space is responsbile for hardware | |
247 | * register reinitialization after open(). | |
248 | */ | |
249 | return 0; | |
250 | } | |
251 | ||
47145210 | 252 | static const struct dev_pm_ops uio_pdrv_genirq_dev_pm_ops = { |
af76756e MD |
253 | .runtime_suspend = uio_pdrv_genirq_runtime_nop, |
254 | .runtime_resume = uio_pdrv_genirq_runtime_nop, | |
255 | }; | |
256 | ||
27760f86 | 257 | #ifdef CONFIG_OF |
05c3e0bb PM |
258 | static struct of_device_id uio_of_genirq_match[] = { |
259 | { /* This is filled with module_parm */ }, | |
260 | { /* Sentinel */ }, | |
27760f86 HK |
261 | }; |
262 | MODULE_DEVICE_TABLE(of, uio_of_genirq_match); | |
05c3e0bb PM |
263 | module_param_string(of_id, uio_of_genirq_match[0].compatible, 128, 0); |
264 | MODULE_PARM_DESC(of_id, "Openfirmware id of the device to be handled by uio"); | |
27760f86 HK |
265 | #endif |
266 | ||
c767db0a MD |
267 | static struct platform_driver uio_pdrv_genirq = { |
268 | .probe = uio_pdrv_genirq_probe, | |
c767db0a MD |
269 | .driver = { |
270 | .name = DRIVER_NAME, | |
af76756e | 271 | .pm = &uio_pdrv_genirq_dev_pm_ops, |
cee4fbd6 | 272 | .of_match_table = of_match_ptr(uio_of_genirq_match), |
c767db0a MD |
273 | }, |
274 | }; | |
275 | ||
11e3123d | 276 | module_platform_driver(uio_pdrv_genirq); |
c767db0a MD |
277 | |
278 | MODULE_AUTHOR("Magnus Damm"); | |
279 | MODULE_DESCRIPTION("Userspace I/O platform driver with generic IRQ handling"); | |
280 | MODULE_LICENSE("GPL v2"); | |
281 | MODULE_ALIAS("platform:" DRIVER_NAME); |