tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * Copyright (C) 2012 CERN (www.cern.ch)
3 * Author: Alessandro Rubini <rubini@gnudd.com>
4 *
5 * Released according to the GNU GPL, version 2 or any later version.
6 *
7 * This work is part of the White Rabbit project, a research effort led
8 * by CERN, the European Institute for Nuclear Research.
9 */
10#include <linux/module.h>
11#include <linux/init.h>
12#include <linux/list.h>
13#include <linux/slab.h>
14#include <linux/fs.h>
15#include <linux/miscdevice.h>
16#include <linux/spinlock.h>
17#include <linux/fmc.h>
18#include <linux/uaccess.h>
19
20static LIST_HEAD(fc_devices);
21static DEFINE_SPINLOCK(fc_lock);
22
23struct fc_instance {
24 struct list_head list;
25 struct fmc_device *fmc;
26 struct miscdevice misc;
27};
28
29/* at open time, we must identify our device */
30static int fc_open(struct inode *ino, struct file *f)
31{
32 struct fmc_device *fmc;
33 struct fc_instance *fc;
34 int minor = iminor(ino);
35
36 list_for_each_entry(fc, &fc_devices, list)
37 if (fc->misc.minor == minor)
38 break;
39 if (fc->misc.minor != minor)
40 return -ENODEV;
41 fmc = fc->fmc;
42 if (try_module_get(fmc->owner) == 0)
43 return -ENODEV;
44
45 f->private_data = fmc;
46 return 0;
47}
48
49static int fc_release(struct inode *ino, struct file *f)
50{
51 struct fmc_device *fmc = f->private_data;
52 module_put(fmc->owner);
53 return 0;
54}
55
56/* read and write are simple after the default llseek has been used */
57static ssize_t fc_read(struct file *f, char __user *buf, size_t count,
58 loff_t *offp)
59{
60 struct fmc_device *fmc = f->private_data;
61 unsigned long addr;
62 uint32_t val;
63
64 if (count < sizeof(val))
65 return -EINVAL;
66 count = sizeof(val);
67
68 addr = *offp;
69 if (addr > fmc->memlen)
70 return -ESPIPE; /* Illegal seek */
71 val = fmc_readl(fmc, addr);
72 if (copy_to_user(buf, &val, count))
73 return -EFAULT;
74 *offp += count;
75 return count;
76}
77
78static ssize_t fc_write(struct file *f, const char __user *buf, size_t count,
79 loff_t *offp)
80{
81 struct fmc_device *fmc = f->private_data;
82 unsigned long addr;
83 uint32_t val;
84
85 if (count < sizeof(val))
86 return -EINVAL;
87 count = sizeof(val);
88
89 addr = *offp;
90 if (addr > fmc->memlen)
91 return -ESPIPE; /* Illegal seek */
92 if (copy_from_user(&val, buf, count))
93 return -EFAULT;
94 fmc_writel(fmc, val, addr);
95 *offp += count;
96 return count;
97}
98
99static const struct file_operations fc_fops = {
100 .owner = THIS_MODULE,
101 .open = fc_open,
102 .release = fc_release,
103 .llseek = generic_file_llseek,
104 .read = fc_read,
105 .write = fc_write,
106};
107
108
109/* Device part .. */
110static int fc_probe(struct fmc_device *fmc);
111static int fc_remove(struct fmc_device *fmc);
112
113static struct fmc_driver fc_drv = {
114 .version = FMC_VERSION,
115 .driver.name = KBUILD_MODNAME,
116 .probe = fc_probe,
117 .remove = fc_remove,
118 /* no table: we want to match everything */
119};
120
121/* We accept the generic busid parameter */
122FMC_PARAM_BUSID(fc_drv);
123
124/* probe and remove must allocate and release a misc device */
125static int fc_probe(struct fmc_device *fmc)
126{
127 int ret;
128 int index = 0;
129
130 struct fc_instance *fc;
131
132 index = fmc_validate(fmc, &fc_drv);
133 if (index < 0)
134 return -EINVAL; /* not our device: invalid */
135
136 /* Create a char device: we want to create it anew */
137 fc = kzalloc(sizeof(*fc), GFP_KERNEL);
138 if (!fc)
139 return -ENOMEM;
140 fc->fmc = fmc;
141 fc->misc.minor = MISC_DYNAMIC_MINOR;
142 fc->misc.fops = &fc_fops;
143 fc->misc.name = kstrdup(dev_name(&fmc->dev), GFP_KERNEL);
144
145 ret = misc_register(&fc->misc);
146 if (ret < 0)
147 goto out;
148 spin_lock(&fc_lock);
149 list_add(&fc->list, &fc_devices);
150 spin_unlock(&fc_lock);
151 dev_info(&fc->fmc->dev, "Created misc device \"%s\"\n",
152 fc->misc.name);
153 return 0;
154
155out:
156 kfree(fc->misc.name);
157 kfree(fc);
158 return ret;
159}
160
161static int fc_remove(struct fmc_device *fmc)
162{
163 struct fc_instance *fc;
164
165 list_for_each_entry(fc, &fc_devices, list)
166 if (fc->fmc == fmc)
167 break;
168 if (fc->fmc != fmc) {
169 dev_err(&fmc->dev, "remove called but not found\n");
170 return -ENODEV;
171 }
172
173 spin_lock(&fc_lock);
174 list_del(&fc->list);
175 spin_unlock(&fc_lock);
176 misc_deregister(&fc->misc);
177 kfree(fc->misc.name);
178 kfree(fc);
179
180 return 0;
181}
182
183
184static int fc_init(void)
185{
186 int ret;
187
188 ret = fmc_driver_register(&fc_drv);
189 return ret;
190}
191
192static void fc_exit(void)
193{
194 fmc_driver_unregister(&fc_drv);
195}
196
197module_init(fc_init);
198module_exit(fc_exit);
199
200MODULE_LICENSE("GPL");