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![Greg Kroah-Hartman](/assets/img/avatar_default.png)
Now that device_create() has been audited, rename things back to the original call to be sane. Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
311 lines
7.9 KiB
C
311 lines
7.9 KiB
C
/* IBM POWER Barrier Synchronization Register Driver
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*
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* Copyright IBM Corporation 2008
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*
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* Author: Sonny Rao <sonnyrao@us.ibm.com>
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*
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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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*
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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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*
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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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#include <linux/kernel.h>
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#include <linux/of.h>
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#include <linux/of_device.h>
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#include <linux/of_platform.h>
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#include <linux/module.h>
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#include <linux/cdev.h>
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#include <linux/list.h>
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#include <linux/mm.h>
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#include <asm/io.h>
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/*
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This driver exposes a special register which can be used for fast
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synchronization across a large SMP machine. The hardware is exposed
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as an array of bytes where each process will write to one of the bytes to
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indicate it has finished the current stage and this update is broadcast to
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all processors without having to bounce a cacheline between them. In
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POWER5 and POWER6 there is one of these registers per SMP, but it is
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presented in two forms; first, it is given as a whole and then as a number
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of smaller registers which alias to parts of the single whole register.
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This can potentially allow multiple groups of processes to each have their
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own private synchronization device.
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Note that this hardware *must* be written to using *only* single byte writes.
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It may be read using 1, 2, 4, or 8 byte loads which must be aligned since
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this region is treated as cache-inhibited processes should also use a
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full sync before and after writing to the BSR to ensure all stores and
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the BSR update have made it to all chips in the system
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*/
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/* This is arbitrary number, up to Power6 it's been 17 or fewer */
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#define BSR_MAX_DEVS (32)
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struct bsr_dev {
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u64 bsr_addr; /* Real address */
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u64 bsr_len; /* length of mem region we can map */
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unsigned bsr_bytes; /* size of the BSR reg itself */
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unsigned bsr_stride; /* interval at which BSR repeats in the page */
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unsigned bsr_type; /* maps to enum below */
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unsigned bsr_num; /* bsr id number for its type */
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int bsr_minor;
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dev_t bsr_dev;
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struct cdev bsr_cdev;
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struct device *bsr_device;
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char bsr_name[32];
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};
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static unsigned num_bsr_devs;
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static struct bsr_dev *bsr_devs;
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static struct class *bsr_class;
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static int bsr_major;
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enum {
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BSR_8 = 0,
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BSR_16 = 1,
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BSR_64 = 2,
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BSR_128 = 3,
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BSR_UNKNOWN = 4,
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BSR_MAX = 5,
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};
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static unsigned bsr_types[BSR_MAX];
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static ssize_t
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bsr_size_show(struct device *dev, struct device_attribute *attr, char *buf)
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{
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struct bsr_dev *bsr_dev = dev_get_drvdata(dev);
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return sprintf(buf, "%u\n", bsr_dev->bsr_bytes);
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}
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static ssize_t
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bsr_stride_show(struct device *dev, struct device_attribute *attr, char *buf)
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{
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struct bsr_dev *bsr_dev = dev_get_drvdata(dev);
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return sprintf(buf, "%u\n", bsr_dev->bsr_stride);
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}
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static ssize_t
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bsr_len_show(struct device *dev, struct device_attribute *attr, char *buf)
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{
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struct bsr_dev *bsr_dev = dev_get_drvdata(dev);
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return sprintf(buf, "%lu\n", bsr_dev->bsr_len);
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}
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static struct device_attribute bsr_dev_attrs[] = {
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__ATTR(bsr_size, S_IRUGO, bsr_size_show, NULL),
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__ATTR(bsr_stride, S_IRUGO, bsr_stride_show, NULL),
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__ATTR(bsr_length, S_IRUGO, bsr_len_show, NULL),
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__ATTR_NULL
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};
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static int bsr_mmap(struct file *filp, struct vm_area_struct *vma)
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{
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unsigned long size = vma->vm_end - vma->vm_start;
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struct bsr_dev *dev = filp->private_data;
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if (size > dev->bsr_len || (size & (PAGE_SIZE-1)))
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return -EINVAL;
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vma->vm_flags |= (VM_IO | VM_DONTEXPAND);
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vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
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if (io_remap_pfn_range(vma, vma->vm_start, dev->bsr_addr >> PAGE_SHIFT,
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size, vma->vm_page_prot))
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return -EAGAIN;
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return 0;
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}
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static int bsr_open(struct inode * inode, struct file * filp)
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{
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struct cdev *cdev = inode->i_cdev;
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struct bsr_dev *dev = container_of(cdev, struct bsr_dev, bsr_cdev);
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filp->private_data = dev;
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return 0;
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}
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const static struct file_operations bsr_fops = {
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.owner = THIS_MODULE,
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.mmap = bsr_mmap,
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.open = bsr_open,
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};
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static void bsr_cleanup_devs(void)
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{
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int i;
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for (i=0 ; i < num_bsr_devs; i++) {
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struct bsr_dev *cur = bsr_devs + i;
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if (cur->bsr_device) {
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cdev_del(&cur->bsr_cdev);
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device_del(cur->bsr_device);
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}
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}
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kfree(bsr_devs);
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}
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static int bsr_create_devs(struct device_node *bn)
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{
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int bsr_stride_len, bsr_bytes_len;
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const u32 *bsr_stride;
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const u32 *bsr_bytes;
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unsigned i;
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bsr_stride = of_get_property(bn, "ibm,lock-stride", &bsr_stride_len);
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bsr_bytes = of_get_property(bn, "ibm,#lock-bytes", &bsr_bytes_len);
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if (!bsr_stride || !bsr_bytes ||
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(bsr_stride_len != bsr_bytes_len)) {
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printk(KERN_ERR "bsr of-node has missing/incorrect property\n");
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return -ENODEV;
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}
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num_bsr_devs = bsr_bytes_len / sizeof(u32);
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/* only a warning, its informational since we'll fail and exit */
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WARN_ON(num_bsr_devs > BSR_MAX_DEVS);
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bsr_devs = kzalloc(sizeof(struct bsr_dev) * num_bsr_devs, GFP_KERNEL);
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if (!bsr_devs)
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return -ENOMEM;
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for (i = 0 ; i < num_bsr_devs; i++) {
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struct bsr_dev *cur = bsr_devs + i;
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struct resource res;
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int result;
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result = of_address_to_resource(bn, i, &res);
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if (result < 0) {
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printk(KERN_ERR "bsr of-node has invalid reg property\n");
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goto out_err;
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}
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cur->bsr_minor = i;
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cur->bsr_addr = res.start;
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cur->bsr_len = res.end - res.start + 1;
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cur->bsr_bytes = bsr_bytes[i];
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cur->bsr_stride = bsr_stride[i];
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cur->bsr_dev = MKDEV(bsr_major, i);
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switch(cur->bsr_bytes) {
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case 8:
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cur->bsr_type = BSR_8;
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break;
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case 16:
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cur->bsr_type = BSR_16;
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break;
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case 64:
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cur->bsr_type = BSR_64;
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break;
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case 128:
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cur->bsr_type = BSR_128;
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break;
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default:
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cur->bsr_type = BSR_UNKNOWN;
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printk(KERN_INFO "unknown BSR size %d\n",cur->bsr_bytes);
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}
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cur->bsr_num = bsr_types[cur->bsr_type];
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bsr_types[cur->bsr_type] = cur->bsr_num + 1;
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snprintf(cur->bsr_name, 32, "bsr%d_%d",
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cur->bsr_bytes, cur->bsr_num);
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cdev_init(&cur->bsr_cdev, &bsr_fops);
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result = cdev_add(&cur->bsr_cdev, cur->bsr_dev, 1);
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if (result)
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goto out_err;
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cur->bsr_device = device_create(bsr_class, NULL, cur->bsr_dev,
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cur, cur->bsr_name);
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if (!cur->bsr_device) {
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printk(KERN_ERR "device_create failed for %s\n",
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cur->bsr_name);
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cdev_del(&cur->bsr_cdev);
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goto out_err;
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}
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}
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return 0;
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out_err:
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bsr_cleanup_devs();
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return -ENODEV;
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}
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static int __init bsr_init(void)
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{
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struct device_node *np;
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dev_t bsr_dev = MKDEV(bsr_major, 0);
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int ret = -ENODEV;
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int result;
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np = of_find_compatible_node(NULL, "ibm,bsr", "ibm,bsr");
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if (!np)
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goto out_err;
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bsr_class = class_create(THIS_MODULE, "bsr");
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if (IS_ERR(bsr_class)) {
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printk(KERN_ERR "class_create() failed for bsr_class\n");
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goto out_err_1;
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}
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bsr_class->dev_attrs = bsr_dev_attrs;
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result = alloc_chrdev_region(&bsr_dev, 0, BSR_MAX_DEVS, "bsr");
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bsr_major = MAJOR(bsr_dev);
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if (result < 0) {
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printk(KERN_ERR "alloc_chrdev_region() failed for bsr\n");
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goto out_err_2;
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}
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if ((ret = bsr_create_devs(np)) < 0)
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goto out_err_3;
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of_node_put(np);
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return 0;
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out_err_3:
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unregister_chrdev_region(bsr_dev, BSR_MAX_DEVS);
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out_err_2:
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class_destroy(bsr_class);
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out_err_1:
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of_node_put(np);
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out_err:
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return ret;
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}
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static void __exit bsr_exit(void)
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{
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bsr_cleanup_devs();
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if (bsr_class)
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class_destroy(bsr_class);
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if (bsr_major)
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unregister_chrdev_region(MKDEV(bsr_major, 0), BSR_MAX_DEVS);
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}
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module_init(bsr_init);
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module_exit(bsr_exit);
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Sonny Rao <sonnyrao@us.ibm.com>");
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