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2b8693c061
Many struct file_operations in the kernel can be "const". Marking them const moves these to the .rodata section, which avoids false sharing with potential dirty data. In addition it'll catch accidental writes at compile time to these shared resources. Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
512 lines
13 KiB
C
512 lines
13 KiB
C
/*
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i2c-dev.c - i2c-bus driver, char device interface
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Copyright (C) 1995-97 Simon G. Vogl
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Copyright (C) 1998-99 Frodo Looijaard <frodol@dds.nl>
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Copyright (C) 2003 Greg Kroah-Hartman <greg@kroah.com>
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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/* Note that this is a complete rewrite of Simon Vogl's i2c-dev module.
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But I have used so much of his original code and ideas that it seems
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only fair to recognize him as co-author -- Frodo */
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/* The I2C_RDWR ioctl code is written by Kolja Waschk <waschk@telos.de> */
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/fs.h>
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#include <linux/slab.h>
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#include <linux/smp_lock.h>
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#include <linux/init.h>
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#include <linux/list.h>
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#include <linux/i2c.h>
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#include <linux/i2c-dev.h>
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#include <asm/uaccess.h>
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static struct i2c_driver i2cdev_driver;
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struct i2c_dev {
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struct list_head list;
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struct i2c_adapter *adap;
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struct device *dev;
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};
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#define I2C_MINORS 256
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static LIST_HEAD(i2c_dev_list);
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static DEFINE_SPINLOCK(i2c_dev_list_lock);
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static struct i2c_dev *i2c_dev_get_by_minor(unsigned index)
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{
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struct i2c_dev *i2c_dev;
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spin_lock(&i2c_dev_list_lock);
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list_for_each_entry(i2c_dev, &i2c_dev_list, list) {
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if (i2c_dev->adap->nr == index)
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goto found;
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}
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i2c_dev = NULL;
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found:
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spin_unlock(&i2c_dev_list_lock);
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return i2c_dev;
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}
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static struct i2c_dev *get_free_i2c_dev(struct i2c_adapter *adap)
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{
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struct i2c_dev *i2c_dev;
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if (adap->nr >= I2C_MINORS) {
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printk(KERN_ERR "i2c-dev: Out of device minors (%d)\n",
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adap->nr);
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return ERR_PTR(-ENODEV);
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}
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i2c_dev = kzalloc(sizeof(*i2c_dev), GFP_KERNEL);
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if (!i2c_dev)
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return ERR_PTR(-ENOMEM);
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i2c_dev->adap = adap;
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spin_lock(&i2c_dev_list_lock);
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list_add_tail(&i2c_dev->list, &i2c_dev_list);
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spin_unlock(&i2c_dev_list_lock);
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return i2c_dev;
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}
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static void return_i2c_dev(struct i2c_dev *i2c_dev)
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{
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spin_lock(&i2c_dev_list_lock);
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list_del(&i2c_dev->list);
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spin_unlock(&i2c_dev_list_lock);
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kfree(i2c_dev);
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}
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static ssize_t show_adapter_name(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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struct i2c_dev *i2c_dev = i2c_dev_get_by_minor(MINOR(dev->devt));
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if (!i2c_dev)
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return -ENODEV;
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return sprintf(buf, "%s\n", i2c_dev->adap->name);
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}
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static DEVICE_ATTR(name, S_IRUGO, show_adapter_name, NULL);
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static ssize_t i2cdev_read (struct file *file, char __user *buf, size_t count,
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loff_t *offset)
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{
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char *tmp;
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int ret;
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struct i2c_client *client = (struct i2c_client *)file->private_data;
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if (count > 8192)
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count = 8192;
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tmp = kmalloc(count,GFP_KERNEL);
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if (tmp==NULL)
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return -ENOMEM;
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pr_debug("i2c-dev: i2c-%d reading %zd bytes.\n",
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iminor(file->f_path.dentry->d_inode), count);
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ret = i2c_master_recv(client,tmp,count);
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if (ret >= 0)
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ret = copy_to_user(buf,tmp,count)?-EFAULT:ret;
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kfree(tmp);
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return ret;
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}
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static ssize_t i2cdev_write (struct file *file, const char __user *buf, size_t count,
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loff_t *offset)
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{
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int ret;
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char *tmp;
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struct i2c_client *client = (struct i2c_client *)file->private_data;
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if (count > 8192)
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count = 8192;
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tmp = kmalloc(count,GFP_KERNEL);
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if (tmp==NULL)
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return -ENOMEM;
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if (copy_from_user(tmp,buf,count)) {
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kfree(tmp);
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return -EFAULT;
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}
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pr_debug("i2c-dev: i2c-%d writing %zd bytes.\n",
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iminor(file->f_path.dentry->d_inode), count);
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ret = i2c_master_send(client,tmp,count);
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kfree(tmp);
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return ret;
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}
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static int i2cdev_ioctl(struct inode *inode, struct file *file,
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unsigned int cmd, unsigned long arg)
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{
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struct i2c_client *client = (struct i2c_client *)file->private_data;
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struct i2c_rdwr_ioctl_data rdwr_arg;
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struct i2c_smbus_ioctl_data data_arg;
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union i2c_smbus_data temp;
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struct i2c_msg *rdwr_pa;
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u8 __user **data_ptrs;
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int i,datasize,res;
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unsigned long funcs;
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dev_dbg(&client->adapter->dev, "ioctl, cmd=0x%02x, arg=0x%02lx\n",
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cmd, arg);
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switch ( cmd ) {
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case I2C_SLAVE:
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case I2C_SLAVE_FORCE:
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if ((arg > 0x3ff) ||
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(((client->flags & I2C_M_TEN) == 0) && arg > 0x7f))
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return -EINVAL;
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if ((cmd == I2C_SLAVE) && i2c_check_addr(client->adapter,arg))
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return -EBUSY;
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client->addr = arg;
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return 0;
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case I2C_TENBIT:
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if (arg)
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client->flags |= I2C_M_TEN;
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else
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client->flags &= ~I2C_M_TEN;
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return 0;
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case I2C_PEC:
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if (arg)
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client->flags |= I2C_CLIENT_PEC;
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else
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client->flags &= ~I2C_CLIENT_PEC;
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return 0;
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case I2C_FUNCS:
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funcs = i2c_get_functionality(client->adapter);
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return put_user(funcs, (unsigned long __user *)arg);
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case I2C_RDWR:
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if (copy_from_user(&rdwr_arg,
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(struct i2c_rdwr_ioctl_data __user *)arg,
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sizeof(rdwr_arg)))
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return -EFAULT;
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/* Put an arbitrary limit on the number of messages that can
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* be sent at once */
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if (rdwr_arg.nmsgs > I2C_RDRW_IOCTL_MAX_MSGS)
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return -EINVAL;
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rdwr_pa = (struct i2c_msg *)
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kmalloc(rdwr_arg.nmsgs * sizeof(struct i2c_msg),
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GFP_KERNEL);
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if (rdwr_pa == NULL) return -ENOMEM;
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if (copy_from_user(rdwr_pa, rdwr_arg.msgs,
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rdwr_arg.nmsgs * sizeof(struct i2c_msg))) {
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kfree(rdwr_pa);
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return -EFAULT;
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}
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data_ptrs = kmalloc(rdwr_arg.nmsgs * sizeof(u8 __user *), GFP_KERNEL);
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if (data_ptrs == NULL) {
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kfree(rdwr_pa);
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return -ENOMEM;
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}
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res = 0;
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for( i=0; i<rdwr_arg.nmsgs; i++ ) {
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/* Limit the size of the message to a sane amount */
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if (rdwr_pa[i].len > 8192) {
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res = -EINVAL;
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break;
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}
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data_ptrs[i] = (u8 __user *)rdwr_pa[i].buf;
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rdwr_pa[i].buf = kmalloc(rdwr_pa[i].len, GFP_KERNEL);
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if(rdwr_pa[i].buf == NULL) {
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res = -ENOMEM;
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break;
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}
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if(copy_from_user(rdwr_pa[i].buf,
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data_ptrs[i],
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rdwr_pa[i].len)) {
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++i; /* Needs to be kfreed too */
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res = -EFAULT;
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break;
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}
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}
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if (res < 0) {
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int j;
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for (j = 0; j < i; ++j)
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kfree(rdwr_pa[j].buf);
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kfree(data_ptrs);
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kfree(rdwr_pa);
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return res;
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}
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res = i2c_transfer(client->adapter,
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rdwr_pa,
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rdwr_arg.nmsgs);
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while(i-- > 0) {
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if( res>=0 && (rdwr_pa[i].flags & I2C_M_RD)) {
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if(copy_to_user(
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data_ptrs[i],
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rdwr_pa[i].buf,
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rdwr_pa[i].len)) {
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res = -EFAULT;
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}
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}
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kfree(rdwr_pa[i].buf);
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}
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kfree(data_ptrs);
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kfree(rdwr_pa);
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return res;
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case I2C_SMBUS:
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if (copy_from_user(&data_arg,
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(struct i2c_smbus_ioctl_data __user *) arg,
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sizeof(struct i2c_smbus_ioctl_data)))
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return -EFAULT;
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if ((data_arg.size != I2C_SMBUS_BYTE) &&
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(data_arg.size != I2C_SMBUS_QUICK) &&
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(data_arg.size != I2C_SMBUS_BYTE_DATA) &&
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(data_arg.size != I2C_SMBUS_WORD_DATA) &&
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(data_arg.size != I2C_SMBUS_PROC_CALL) &&
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(data_arg.size != I2C_SMBUS_BLOCK_DATA) &&
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(data_arg.size != I2C_SMBUS_I2C_BLOCK_DATA) &&
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(data_arg.size != I2C_SMBUS_BLOCK_PROC_CALL)) {
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dev_dbg(&client->adapter->dev,
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"size out of range (%x) in ioctl I2C_SMBUS.\n",
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data_arg.size);
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return -EINVAL;
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}
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/* Note that I2C_SMBUS_READ and I2C_SMBUS_WRITE are 0 and 1,
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so the check is valid if size==I2C_SMBUS_QUICK too. */
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if ((data_arg.read_write != I2C_SMBUS_READ) &&
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(data_arg.read_write != I2C_SMBUS_WRITE)) {
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dev_dbg(&client->adapter->dev,
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"read_write out of range (%x) in ioctl I2C_SMBUS.\n",
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data_arg.read_write);
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return -EINVAL;
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}
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/* Note that command values are always valid! */
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if ((data_arg.size == I2C_SMBUS_QUICK) ||
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((data_arg.size == I2C_SMBUS_BYTE) &&
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(data_arg.read_write == I2C_SMBUS_WRITE)))
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/* These are special: we do not use data */
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return i2c_smbus_xfer(client->adapter, client->addr,
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client->flags,
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data_arg.read_write,
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data_arg.command,
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data_arg.size, NULL);
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if (data_arg.data == NULL) {
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dev_dbg(&client->adapter->dev,
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"data is NULL pointer in ioctl I2C_SMBUS.\n");
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return -EINVAL;
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}
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if ((data_arg.size == I2C_SMBUS_BYTE_DATA) ||
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(data_arg.size == I2C_SMBUS_BYTE))
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datasize = sizeof(data_arg.data->byte);
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else if ((data_arg.size == I2C_SMBUS_WORD_DATA) ||
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(data_arg.size == I2C_SMBUS_PROC_CALL))
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datasize = sizeof(data_arg.data->word);
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else /* size == smbus block, i2c block, or block proc. call */
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datasize = sizeof(data_arg.data->block);
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if ((data_arg.size == I2C_SMBUS_PROC_CALL) ||
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(data_arg.size == I2C_SMBUS_BLOCK_PROC_CALL) ||
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(data_arg.read_write == I2C_SMBUS_WRITE)) {
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if (copy_from_user(&temp, data_arg.data, datasize))
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return -EFAULT;
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}
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res = i2c_smbus_xfer(client->adapter,client->addr,client->flags,
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data_arg.read_write,
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data_arg.command,data_arg.size,&temp);
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if (! res && ((data_arg.size == I2C_SMBUS_PROC_CALL) ||
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(data_arg.size == I2C_SMBUS_BLOCK_PROC_CALL) ||
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(data_arg.read_write == I2C_SMBUS_READ))) {
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if (copy_to_user(data_arg.data, &temp, datasize))
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return -EFAULT;
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}
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return res;
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default:
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return i2c_control(client,cmd,arg);
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}
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return 0;
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}
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static int i2cdev_open(struct inode *inode, struct file *file)
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{
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unsigned int minor = iminor(inode);
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struct i2c_client *client;
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struct i2c_adapter *adap;
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struct i2c_dev *i2c_dev;
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i2c_dev = i2c_dev_get_by_minor(minor);
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if (!i2c_dev)
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return -ENODEV;
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adap = i2c_get_adapter(i2c_dev->adap->nr);
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if (!adap)
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return -ENODEV;
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client = kzalloc(sizeof(*client), GFP_KERNEL);
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if (!client) {
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i2c_put_adapter(adap);
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return -ENOMEM;
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}
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snprintf(client->name, I2C_NAME_SIZE, "i2c-dev %d", adap->nr);
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client->driver = &i2cdev_driver;
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/* registered with adapter, passed as client to user */
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client->adapter = adap;
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file->private_data = client;
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return 0;
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}
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static int i2cdev_release(struct inode *inode, struct file *file)
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{
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struct i2c_client *client = file->private_data;
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i2c_put_adapter(client->adapter);
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kfree(client);
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file->private_data = NULL;
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return 0;
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}
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static const struct file_operations i2cdev_fops = {
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.owner = THIS_MODULE,
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.llseek = no_llseek,
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.read = i2cdev_read,
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.write = i2cdev_write,
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.ioctl = i2cdev_ioctl,
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.open = i2cdev_open,
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.release = i2cdev_release,
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};
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static struct class *i2c_dev_class;
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static int i2cdev_attach_adapter(struct i2c_adapter *adap)
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{
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struct i2c_dev *i2c_dev;
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int res;
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i2c_dev = get_free_i2c_dev(adap);
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if (IS_ERR(i2c_dev))
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return PTR_ERR(i2c_dev);
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/* register this i2c device with the driver core */
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i2c_dev->dev = device_create(i2c_dev_class, &adap->dev,
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MKDEV(I2C_MAJOR, adap->nr),
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"i2c-%d", adap->nr);
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if (IS_ERR(i2c_dev->dev)) {
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res = PTR_ERR(i2c_dev->dev);
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goto error;
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}
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res = device_create_file(i2c_dev->dev, &dev_attr_name);
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if (res)
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goto error_destroy;
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pr_debug("i2c-dev: adapter [%s] registered as minor %d\n",
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adap->name, adap->nr);
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return 0;
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error_destroy:
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device_destroy(i2c_dev_class, MKDEV(I2C_MAJOR, adap->nr));
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error:
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return_i2c_dev(i2c_dev);
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return res;
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}
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static int i2cdev_detach_adapter(struct i2c_adapter *adap)
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{
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struct i2c_dev *i2c_dev;
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i2c_dev = i2c_dev_get_by_minor(adap->nr);
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if (!i2c_dev) /* attach_adapter must have failed */
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return 0;
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device_remove_file(i2c_dev->dev, &dev_attr_name);
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return_i2c_dev(i2c_dev);
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device_destroy(i2c_dev_class, MKDEV(I2C_MAJOR, adap->nr));
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pr_debug("i2c-dev: adapter [%s] unregistered\n", adap->name);
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return 0;
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}
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static int i2cdev_detach_client(struct i2c_client *client)
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{
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return 0;
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}
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static struct i2c_driver i2cdev_driver = {
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.driver = {
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.name = "dev_driver",
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},
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.id = I2C_DRIVERID_I2CDEV,
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.attach_adapter = i2cdev_attach_adapter,
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.detach_adapter = i2cdev_detach_adapter,
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.detach_client = i2cdev_detach_client,
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};
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static int __init i2c_dev_init(void)
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{
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int res;
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printk(KERN_INFO "i2c /dev entries driver\n");
|
|
|
|
res = register_chrdev(I2C_MAJOR, "i2c", &i2cdev_fops);
|
|
if (res)
|
|
goto out;
|
|
|
|
i2c_dev_class = class_create(THIS_MODULE, "i2c-dev");
|
|
if (IS_ERR(i2c_dev_class))
|
|
goto out_unreg_chrdev;
|
|
|
|
res = i2c_add_driver(&i2cdev_driver);
|
|
if (res)
|
|
goto out_unreg_class;
|
|
|
|
return 0;
|
|
|
|
out_unreg_class:
|
|
class_destroy(i2c_dev_class);
|
|
out_unreg_chrdev:
|
|
unregister_chrdev(I2C_MAJOR, "i2c");
|
|
out:
|
|
printk(KERN_ERR "%s: Driver Initialisation failed\n", __FILE__);
|
|
return res;
|
|
}
|
|
|
|
static void __exit i2c_dev_exit(void)
|
|
{
|
|
i2c_del_driver(&i2cdev_driver);
|
|
class_destroy(i2c_dev_class);
|
|
unregister_chrdev(I2C_MAJOR,"i2c");
|
|
}
|
|
|
|
MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl> and "
|
|
"Simon G. Vogl <simon@tk.uni-linz.ac.at>");
|
|
MODULE_DESCRIPTION("I2C /dev entries driver");
|
|
MODULE_LICENSE("GPL");
|
|
|
|
module_init(i2c_dev_init);
|
|
module_exit(i2c_dev_exit);
|