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c767db0a MD |
1 | /* |
2 | * drivers/uio/uio_pdrv_genirq.c | |
3 | * | |
4 | * Userspace I/O platform driver with generic IRQ handling code. | |
5 | * | |
6 | * Copyright (C) 2008 Magnus Damm | |
7 | * | |
8 | * Based on uio_pdrv.c by Uwe Kleine-Koenig, | |
9 | * Copyright (C) 2008 by Digi International Inc. | |
10 | * All rights reserved. | |
11 | * | |
12 | * This program is free software; you can redistribute it and/or modify it | |
13 | * under the terms of the GNU General Public License version 2 as published by | |
14 | * the Free Software Foundation. | |
15 | */ | |
16 | ||
17 | #include <linux/platform_device.h> | |
18 | #include <linux/uio_driver.h> | |
19 | #include <linux/spinlock.h> | |
20 | #include <linux/bitops.h> | |
21 | #include <linux/interrupt.h> | |
22 | #include <linux/stringify.h> | |
23 | ||
24 | #define DRIVER_NAME "uio_pdrv_genirq" | |
25 | ||
26 | struct uio_pdrv_genirq_platdata { | |
27 | struct uio_info *uioinfo; | |
28 | spinlock_t lock; | |
29 | unsigned long flags; | |
30 | }; | |
31 | ||
32 | static irqreturn_t uio_pdrv_genirq_handler(int irq, struct uio_info *dev_info) | |
33 | { | |
34 | struct uio_pdrv_genirq_platdata *priv = dev_info->priv; | |
35 | ||
36 | /* Just disable the interrupt in the interrupt controller, and | |
37 | * remember the state so we can allow user space to enable it later. | |
38 | */ | |
39 | ||
40 | if (!test_and_set_bit(0, &priv->flags)) | |
41 | disable_irq_nosync(irq); | |
42 | ||
43 | return IRQ_HANDLED; | |
44 | } | |
45 | ||
46 | static int uio_pdrv_genirq_irqcontrol(struct uio_info *dev_info, s32 irq_on) | |
47 | { | |
48 | struct uio_pdrv_genirq_platdata *priv = dev_info->priv; | |
49 | unsigned long flags; | |
50 | ||
51 | /* Allow user space to enable and disable the interrupt | |
52 | * in the interrupt controller, but keep track of the | |
53 | * state to prevent per-irq depth damage. | |
54 | * | |
55 | * Serialize this operation to support multiple tasks. | |
56 | */ | |
57 | ||
58 | spin_lock_irqsave(&priv->lock, flags); | |
59 | if (irq_on) { | |
60 | if (test_and_clear_bit(0, &priv->flags)) | |
61 | enable_irq(dev_info->irq); | |
62 | } else { | |
63 | if (!test_and_set_bit(0, &priv->flags)) | |
64 | disable_irq(dev_info->irq); | |
65 | } | |
66 | spin_unlock_irqrestore(&priv->lock, flags); | |
67 | ||
68 | return 0; | |
69 | } | |
70 | ||
71 | static int uio_pdrv_genirq_probe(struct platform_device *pdev) | |
72 | { | |
73 | struct uio_info *uioinfo = pdev->dev.platform_data; | |
74 | struct uio_pdrv_genirq_platdata *priv; | |
75 | struct uio_mem *uiomem; | |
76 | int ret = -EINVAL; | |
77 | int i; | |
78 | ||
79 | if (!uioinfo || !uioinfo->name || !uioinfo->version) { | |
80 | dev_err(&pdev->dev, "missing platform_data\n"); | |
81 | goto bad0; | |
82 | } | |
83 | ||
e543ae89 MF |
84 | if (uioinfo->handler || uioinfo->irqcontrol || |
85 | uioinfo->irq_flags & IRQF_SHARED) { | |
c767db0a MD |
86 | dev_err(&pdev->dev, "interrupt configuration error\n"); |
87 | goto bad0; | |
88 | } | |
89 | ||
90 | priv = kzalloc(sizeof(*priv), GFP_KERNEL); | |
91 | if (!priv) { | |
92 | ret = -ENOMEM; | |
93 | dev_err(&pdev->dev, "unable to kmalloc\n"); | |
94 | goto bad0; | |
95 | } | |
96 | ||
97 | priv->uioinfo = uioinfo; | |
98 | spin_lock_init(&priv->lock); | |
99 | priv->flags = 0; /* interrupt is enabled to begin with */ | |
100 | ||
101 | uiomem = &uioinfo->mem[0]; | |
102 | ||
103 | for (i = 0; i < pdev->num_resources; ++i) { | |
104 | struct resource *r = &pdev->resource[i]; | |
105 | ||
106 | if (r->flags != IORESOURCE_MEM) | |
107 | continue; | |
108 | ||
109 | if (uiomem >= &uioinfo->mem[MAX_UIO_MAPS]) { | |
110 | dev_warn(&pdev->dev, "device has more than " | |
111 | __stringify(MAX_UIO_MAPS) | |
112 | " I/O memory resources.\n"); | |
113 | break; | |
114 | } | |
115 | ||
116 | uiomem->memtype = UIO_MEM_PHYS; | |
117 | uiomem->addr = r->start; | |
118 | uiomem->size = r->end - r->start + 1; | |
119 | ++uiomem; | |
120 | } | |
121 | ||
122 | while (uiomem < &uioinfo->mem[MAX_UIO_MAPS]) { | |
123 | uiomem->size = 0; | |
124 | ++uiomem; | |
125 | } | |
126 | ||
127 | /* This driver requires no hardware specific kernel code to handle | |
128 | * interrupts. Instead, the interrupt handler simply disables the | |
129 | * interrupt in the interrupt controller. User space is responsible | |
130 | * for performing hardware specific acknowledge and re-enabling of | |
131 | * the interrupt in the interrupt controller. | |
132 | * | |
133 | * Interrupt sharing is not supported. | |
134 | */ | |
135 | ||
e543ae89 | 136 | uioinfo->irq_flags |= IRQF_DISABLED; |
c767db0a MD |
137 | uioinfo->handler = uio_pdrv_genirq_handler; |
138 | uioinfo->irqcontrol = uio_pdrv_genirq_irqcontrol; | |
139 | uioinfo->priv = priv; | |
140 | ||
141 | ret = uio_register_device(&pdev->dev, priv->uioinfo); | |
142 | if (ret) { | |
143 | dev_err(&pdev->dev, "unable to register uio device\n"); | |
144 | goto bad1; | |
145 | } | |
146 | ||
147 | platform_set_drvdata(pdev, priv); | |
148 | return 0; | |
149 | bad1: | |
150 | kfree(priv); | |
151 | bad0: | |
152 | return ret; | |
153 | } | |
154 | ||
155 | static int uio_pdrv_genirq_remove(struct platform_device *pdev) | |
156 | { | |
157 | struct uio_pdrv_genirq_platdata *priv = platform_get_drvdata(pdev); | |
158 | ||
159 | uio_unregister_device(priv->uioinfo); | |
160 | kfree(priv); | |
161 | return 0; | |
162 | } | |
163 | ||
164 | static struct platform_driver uio_pdrv_genirq = { | |
165 | .probe = uio_pdrv_genirq_probe, | |
166 | .remove = uio_pdrv_genirq_remove, | |
167 | .driver = { | |
168 | .name = DRIVER_NAME, | |
169 | .owner = THIS_MODULE, | |
170 | }, | |
171 | }; | |
172 | ||
173 | static int __init uio_pdrv_genirq_init(void) | |
174 | { | |
175 | return platform_driver_register(&uio_pdrv_genirq); | |
176 | } | |
177 | ||
178 | static void __exit uio_pdrv_genirq_exit(void) | |
179 | { | |
180 | platform_driver_unregister(&uio_pdrv_genirq); | |
181 | } | |
182 | ||
183 | module_init(uio_pdrv_genirq_init); | |
184 | module_exit(uio_pdrv_genirq_exit); | |
185 | ||
186 | MODULE_AUTHOR("Magnus Damm"); | |
187 | MODULE_DESCRIPTION("Userspace I/O platform driver with generic IRQ handling"); | |
188 | MODULE_LICENSE("GPL v2"); | |
189 | MODULE_ALIAS("platform:" DRIVER_NAME); |