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authorMagnus Damm <magnus.damm@gmail.com>2008-07-11 05:55:27 -0400
committerGreg Kroah-Hartman <gregkh@suse.de>2008-08-21 13:15:39 -0400
commitc767db0ab4bc85f06119f2b42369e31b29991f16 (patch)
treec094d9aa9ece9b80c0df389c11da50913c652ead /drivers/uio
parent0f90927da11d596802d196cf299e91293abc90c5 (diff)
UIO: generic irq handling for some uio platform devices
This is V3 of uio_pdrv_genirq.c, a platform driver for UIO with generic IRQ handling code. This driver is very similar to the regular UIO platform driver, but is only suitable for devices that are connected to the interrupt controller using unique interrupt lines. The uio_pdrv_genirq driver includes generic interrupt handling code which disables the serviced interrupt in the interrupt controller and makes the user space driver responsible for acknowledging the interrupt in the device and reenabling the interrupt in the interrupt controller. Shared interrupts are not supported since the in-kernel interrupt handler will disable the interrupt line in the interrupt controller, and in a shared interrupt configuration this will stop other devices from delivering interrupts. Signed-off-by: Magnus Damm <damm@igel.co.jp> Signed-off-by: Hans J. Koch <hjk@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers/uio')
-rw-r--r--drivers/uio/Kconfig13
-rw-r--r--drivers/uio/Makefile1
-rw-r--r--drivers/uio/uio_pdrv_genirq.c188
3 files changed, 202 insertions, 0 deletions
diff --git a/drivers/uio/Kconfig b/drivers/uio/Kconfig
index 2e9079df26b3..4190be64917f 100644
--- a/drivers/uio/Kconfig
+++ b/drivers/uio/Kconfig
@@ -33,6 +33,19 @@ config UIO_PDRV
33 33
34 If you don't know what to do here, say N. 34 If you don't know what to do here, say N.
35 35
36config UIO_PDRV_GENIRQ
37 tristate "Userspace I/O platform driver with generic IRQ handling"
38 help
39 Platform driver for Userspace I/O devices, including generic
40 interrupt handling code. Shared interrupts are not supported.
41
42 This kernel driver requires that the matching userspace driver
43 handles interrupts in a special way. Userspace is responsible
44 for acknowledging the hardware device if needed, and re-enabling
45 interrupts in the interrupt controller using the write() syscall.
46
47 If you don't know what to do here, say N.
48
36config UIO_SMX 49config UIO_SMX
37 tristate "SMX cryptengine UIO interface" 50 tristate "SMX cryptengine UIO interface"
38 default n 51 default n
diff --git a/drivers/uio/Makefile b/drivers/uio/Makefile
index e00ce0def1a0..8667bbdef904 100644
--- a/drivers/uio/Makefile
+++ b/drivers/uio/Makefile
@@ -1,4 +1,5 @@
1obj-$(CONFIG_UIO) += uio.o 1obj-$(CONFIG_UIO) += uio.o
2obj-$(CONFIG_UIO_CIF) += uio_cif.o 2obj-$(CONFIG_UIO_CIF) += uio_cif.o
3obj-$(CONFIG_UIO_PDRV) += uio_pdrv.o 3obj-$(CONFIG_UIO_PDRV) += uio_pdrv.o
4obj-$(CONFIG_UIO_PDRV_GENIRQ) += uio_pdrv_genirq.o
4obj-$(CONFIG_UIO_SMX) += uio_smx.o 5obj-$(CONFIG_UIO_SMX) += uio_smx.o
diff --git a/drivers/uio/uio_pdrv_genirq.c b/drivers/uio/uio_pdrv_genirq.c
new file mode 100644
index 000000000000..1f82c83a92ae
--- /dev/null
+++ b/drivers/uio/uio_pdrv_genirq.c
@@ -0,0 +1,188 @@
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
26struct uio_pdrv_genirq_platdata {
27 struct uio_info *uioinfo;
28 spinlock_t lock;
29 unsigned long flags;
30};
31
32static 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
46static 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
71static 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
84 if (uioinfo->handler || uioinfo->irqcontrol || uioinfo->irq_flags) {
85 dev_err(&pdev->dev, "interrupt configuration error\n");
86 goto bad0;
87 }
88
89 priv = kzalloc(sizeof(*priv), GFP_KERNEL);
90 if (!priv) {
91 ret = -ENOMEM;
92 dev_err(&pdev->dev, "unable to kmalloc\n");
93 goto bad0;
94 }
95
96 priv->uioinfo = uioinfo;
97 spin_lock_init(&priv->lock);
98 priv->flags = 0; /* interrupt is enabled to begin with */
99
100 uiomem = &uioinfo->mem[0];
101
102 for (i = 0; i < pdev->num_resources; ++i) {
103 struct resource *r = &pdev->resource[i];
104
105 if (r->flags != IORESOURCE_MEM)
106 continue;
107
108 if (uiomem >= &uioinfo->mem[MAX_UIO_MAPS]) {
109 dev_warn(&pdev->dev, "device has more than "
110 __stringify(MAX_UIO_MAPS)
111 " I/O memory resources.\n");
112 break;
113 }
114
115 uiomem->memtype = UIO_MEM_PHYS;
116 uiomem->addr = r->start;
117 uiomem->size = r->end - r->start + 1;
118 ++uiomem;
119 }
120
121 while (uiomem < &uioinfo->mem[MAX_UIO_MAPS]) {
122 uiomem->size = 0;
123 ++uiomem;
124 }
125
126 /* This driver requires no hardware specific kernel code to handle
127 * interrupts. Instead, the interrupt handler simply disables the
128 * interrupt in the interrupt controller. User space is responsible
129 * for performing hardware specific acknowledge and re-enabling of
130 * the interrupt in the interrupt controller.
131 *
132 * Interrupt sharing is not supported.
133 */
134
135 uioinfo->irq_flags = IRQF_DISABLED;
136 uioinfo->handler = uio_pdrv_genirq_handler;
137 uioinfo->irqcontrol = uio_pdrv_genirq_irqcontrol;
138 uioinfo->priv = priv;
139
140 ret = uio_register_device(&pdev->dev, priv->uioinfo);
141 if (ret) {
142 dev_err(&pdev->dev, "unable to register uio device\n");
143 goto bad1;
144 }
145
146 platform_set_drvdata(pdev, priv);
147 return 0;
148 bad1:
149 kfree(priv);
150 bad0:
151 return ret;
152}
153
154static int uio_pdrv_genirq_remove(struct platform_device *pdev)
155{
156 struct uio_pdrv_genirq_platdata *priv = platform_get_drvdata(pdev);
157
158 uio_unregister_device(priv->uioinfo);
159 kfree(priv);
160 return 0;
161}
162
163static struct platform_driver uio_pdrv_genirq = {
164 .probe = uio_pdrv_genirq_probe,
165 .remove = uio_pdrv_genirq_remove,
166 .driver = {
167 .name = DRIVER_NAME,
168 .owner = THIS_MODULE,
169 },
170};
171
172static int __init uio_pdrv_genirq_init(void)
173{
174 return platform_driver_register(&uio_pdrv_genirq);
175}
176
177static void __exit uio_pdrv_genirq_exit(void)
178{
179 platform_driver_unregister(&uio_pdrv_genirq);
180}
181
182module_init(uio_pdrv_genirq_init);
183module_exit(uio_pdrv_genirq_exit);
184
185MODULE_AUTHOR("Magnus Damm");
186MODULE_DESCRIPTION("Userspace I/O platform driver with generic IRQ handling");
187MODULE_LICENSE("GPL v2");
188MODULE_ALIAS("platform:" DRIVER_NAME);