diff options
Diffstat (limited to 'drivers/fmc/fmc-chardev.c')
| -rw-r--r-- | drivers/fmc/fmc-chardev.c | 202 |
1 files changed, 202 insertions, 0 deletions
diff --git a/drivers/fmc/fmc-chardev.c b/drivers/fmc/fmc-chardev.c new file mode 100644 index 000000000000..cc031db2d2a3 --- /dev/null +++ b/drivers/fmc/fmc-chardev.c @@ -0,0 +1,202 @@ +/* + * Copyright (C) 2012 CERN (www.cern.ch) + * Author: Alessandro Rubini <rubini@gnudd.com> + * + * Released according to the GNU GPL, version 2 or any later version. + * + * This work is part of the White Rabbit project, a research effort led + * by CERN, the European Institute for Nuclear Research. + */ +#include <linux/module.h> +#include <linux/init.h> +#include <linux/list.h> +#include <linux/slab.h> +#include <linux/fs.h> +#include <linux/miscdevice.h> +#include <linux/spinlock.h> +#include <linux/fmc.h> +#include <linux/uaccess.h> + +static LIST_HEAD(fc_devices); +static DEFINE_SPINLOCK(fc_lock); + +struct fc_instance { + struct list_head list; + struct fmc_device *fmc; + struct miscdevice misc; +}; + +/* at open time, we must identify our device */ +static int fc_open(struct inode *ino, struct file *f) +{ + struct fmc_device *fmc; + struct fc_instance *fc; + int minor = iminor(ino); + + list_for_each_entry(fc, &fc_devices, list) + if (fc->misc.minor == minor) + break; + if (fc->misc.minor != minor) + return -ENODEV; + fmc = fc->fmc; + if (try_module_get(fmc->owner) == 0) + return -ENODEV; + + f->private_data = fmc; + return 0; +} + +static int fc_release(struct inode *ino, struct file *f) +{ + struct fmc_device *fmc = f->private_data; + module_put(fmc->owner); + return 0; +} + +/* read and write are simple after the default llseek has been used */ +static ssize_t fc_read(struct file *f, char __user *buf, size_t count, + loff_t *offp) +{ + struct fmc_device *fmc = f->private_data; + unsigned long addr; + uint32_t val; + + if (count < sizeof(val)) + return -EINVAL; + count = sizeof(val); + + addr = *offp; + if (addr > fmc->memlen) + return -ESPIPE; /* Illegal seek */ + val = fmc_readl(fmc, addr); + if (copy_to_user(buf, &val, count)) + return -EFAULT; + *offp += count; + return count; +} + +static ssize_t fc_write(struct file *f, const char __user *buf, size_t count, + loff_t *offp) +{ + struct fmc_device *fmc = f->private_data; + unsigned long addr; + uint32_t val; + + if (count < sizeof(val)) + return -EINVAL; + count = sizeof(val); + + addr = *offp; + if (addr > fmc->memlen) + return -ESPIPE; /* Illegal seek */ + if (copy_from_user(&val, buf, count)) + return -EFAULT; + fmc_writel(fmc, val, addr); + *offp += count; + return count; +} + +static const struct file_operations fc_fops = { + .owner = THIS_MODULE, + .open = fc_open, + .release = fc_release, + .llseek = generic_file_llseek, + .read = fc_read, + .write = fc_write, +}; + + +/* Device part .. */ +static int fc_probe(struct fmc_device *fmc); +static int fc_remove(struct fmc_device *fmc); + +static struct fmc_driver fc_drv = { + .version = FMC_VERSION, + .driver.name = KBUILD_MODNAME, + .probe = fc_probe, + .remove = fc_remove, + /* no table: we want to match everything */ +}; + +/* We accept the generic busid parameter */ +FMC_PARAM_BUSID(fc_drv); + +/* probe and remove must allocate and release a misc device */ +static int fc_probe(struct fmc_device *fmc) +{ + int ret; + int index = 0; + + struct fc_instance *fc; + + if (fmc->op->validate) + index = fmc->op->validate(fmc, &fc_drv); + if (index < 0) + return -EINVAL; /* not our device: invalid */ + + /* Create a char device: we want to create it anew */ + fc = kzalloc(sizeof(*fc), GFP_KERNEL); + if (!fc) + return -ENOMEM; + fc->fmc = fmc; + fc->misc.minor = MISC_DYNAMIC_MINOR; + fc->misc.fops = &fc_fops; + fc->misc.name = kstrdup(dev_name(&fmc->dev), GFP_KERNEL); + + spin_lock(&fc_lock); + ret = misc_register(&fc->misc); + if (ret < 0) + goto err_unlock; + list_add(&fc->list, &fc_devices); + spin_unlock(&fc_lock); + dev_info(&fc->fmc->dev, "Created misc device \"%s\"\n", + fc->misc.name); + return 0; + +err_unlock: + spin_unlock(&fc_lock); + kfree(fc->misc.name); + kfree(fc); + return ret; +} + +static int fc_remove(struct fmc_device *fmc) +{ + struct fc_instance *fc; + + list_for_each_entry(fc, &fc_devices, list) + if (fc->fmc == fmc) + break; + if (fc->fmc != fmc) { + dev_err(&fmc->dev, "remove called but not found\n"); + return -ENODEV; + } + + spin_lock(&fc_lock); + list_del(&fc->list); + misc_deregister(&fc->misc); + kfree(fc->misc.name); + kfree(fc); + spin_unlock(&fc_lock); + + return 0; +} + + +static int fc_init(void) +{ + int ret; + + ret = fmc_driver_register(&fc_drv); + return ret; +} + +static void fc_exit(void) +{ + fmc_driver_unregister(&fc_drv); +} + +module_init(fc_init); +module_exit(fc_exit); + +MODULE_LICENSE("GPL"); |