Alessandro Rubini | 4debfe4 | 2013-06-18 23:48:07 +0200 | [diff] [blame] | 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 | |
| 20 | static LIST_HEAD(fc_devices); |
| 21 | static DEFINE_SPINLOCK(fc_lock); |
| 22 | |
| 23 | struct 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 */ |
| 30 | static 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 | |
| 49 | static 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 */ |
| 57 | static 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 | |
| 78 | static 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 | |
| 99 | static 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 .. */ |
| 110 | static int fc_probe(struct fmc_device *fmc); |
| 111 | static int fc_remove(struct fmc_device *fmc); |
| 112 | |
| 113 | static 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 */ |
| 122 | FMC_PARAM_BUSID(fc_drv); |
| 123 | |
| 124 | /* probe and remove must allocate and release a misc device */ |
| 125 | static int fc_probe(struct fmc_device *fmc) |
| 126 | { |
| 127 | int ret; |
| 128 | int index = 0; |
| 129 | |
| 130 | struct fc_instance *fc; |
| 131 | |
| 132 | if (fmc->op->validate) |
| 133 | index = fmc->op->validate(fmc, &fc_drv); |
| 134 | if (index < 0) |
| 135 | return -EINVAL; /* not our device: invalid */ |
| 136 | |
| 137 | /* Create a char device: we want to create it anew */ |
| 138 | fc = kzalloc(sizeof(*fc), GFP_KERNEL); |
Dan Carpenter | 4640a3f | 2013-06-20 11:10:18 +0300 | [diff] [blame^] | 139 | if (!fc) |
| 140 | return -ENOMEM; |
Alessandro Rubini | 4debfe4 | 2013-06-18 23:48:07 +0200 | [diff] [blame] | 141 | fc->fmc = fmc; |
| 142 | fc->misc.minor = MISC_DYNAMIC_MINOR; |
| 143 | fc->misc.fops = &fc_fops; |
| 144 | fc->misc.name = kstrdup(dev_name(&fmc->dev), GFP_KERNEL); |
| 145 | |
| 146 | spin_lock(&fc_lock); |
| 147 | ret = misc_register(&fc->misc); |
Dan Carpenter | 4640a3f | 2013-06-20 11:10:18 +0300 | [diff] [blame^] | 148 | if (ret < 0) |
| 149 | goto err_unlock; |
| 150 | list_add(&fc->list, &fc_devices); |
Alessandro Rubini | 4debfe4 | 2013-06-18 23:48:07 +0200 | [diff] [blame] | 151 | spin_unlock(&fc_lock); |
| 152 | dev_info(&fc->fmc->dev, "Created misc device \"%s\"\n", |
| 153 | fc->misc.name); |
Dan Carpenter | 4640a3f | 2013-06-20 11:10:18 +0300 | [diff] [blame^] | 154 | return 0; |
| 155 | |
| 156 | err_unlock: |
| 157 | spin_unlock(&fc_lock); |
| 158 | kfree(fc->misc.name); |
| 159 | kfree(fc); |
Alessandro Rubini | 4debfe4 | 2013-06-18 23:48:07 +0200 | [diff] [blame] | 160 | return ret; |
| 161 | } |
| 162 | |
| 163 | static int fc_remove(struct fmc_device *fmc) |
| 164 | { |
| 165 | struct fc_instance *fc; |
| 166 | |
| 167 | list_for_each_entry(fc, &fc_devices, list) |
| 168 | if (fc->fmc == fmc) |
| 169 | break; |
| 170 | if (fc->fmc != fmc) { |
| 171 | dev_err(&fmc->dev, "remove called but not found\n"); |
| 172 | return -ENODEV; |
| 173 | } |
| 174 | |
| 175 | spin_lock(&fc_lock); |
| 176 | list_del(&fc->list); |
| 177 | misc_deregister(&fc->misc); |
| 178 | kfree(fc->misc.name); |
| 179 | kfree(fc); |
| 180 | spin_unlock(&fc_lock); |
| 181 | |
| 182 | return 0; |
| 183 | } |
| 184 | |
| 185 | |
| 186 | static int fc_init(void) |
| 187 | { |
| 188 | int ret; |
| 189 | |
| 190 | ret = fmc_driver_register(&fc_drv); |
| 191 | return ret; |
| 192 | } |
| 193 | |
| 194 | static void fc_exit(void) |
| 195 | { |
| 196 | fmc_driver_unregister(&fc_drv); |
| 197 | } |
| 198 | |
| 199 | module_init(fc_init); |
| 200 | module_exit(fc_exit); |
| 201 | |
| 202 | MODULE_LICENSE("GPL"); |