[linux.git] / drivers / char / bsr.c

/* IBM POWER Barrier Synchronization Register Driver
 *
 * Copyright IBM Corporation 2008
 *
 * Author: Sonny Rao <[email protected]>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 */

#include <linux/kernel.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/of_platform.h>
#include <linux/fs.h>
#include <linux/module.h>
#include <linux/cdev.h>
#include <linux/list.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <asm/pgtable.h>
#include <asm/io.h>

/*
 This driver exposes a special register which can be used for fast
 synchronization across a large SMP machine.  The hardware is exposed
 as an array of bytes where each process will write to one of the bytes to
 indicate it has finished the current stage and this update is broadcast to
 all processors without having to bounce a cacheline between them. In
 POWER5 and POWER6 there is one of these registers per SMP,  but it is
 presented in two forms; first, it is given as a whole and then as a number
 of smaller registers which alias to parts of the single whole register.
 This can potentially allow multiple groups of processes to each have their
 own private synchronization device.

 Note that this hardware *must* be written to using *only* single byte writes.
 It may be read using 1, 2, 4, or 8 byte loads which must be aligned since
 this region is treated as cache-inhibited  processes should also use a
 full sync before and after writing to the BSR to ensure all stores and
 the BSR update have made it to all chips in the system
*/

/* This is arbitrary number, up to Power6 it's been 17 or fewer  */
#define BSR_MAX_DEVS (32)

struct bsr_dev {
	u64      bsr_addr;     /* Real address */
	u64      bsr_len;      /* length of mem region we can map */
	unsigned bsr_bytes;    /* size of the BSR reg itself */
	unsigned bsr_stride;   /* interval at which BSR repeats in the page */
	unsigned bsr_type;     /* maps to enum below */
	unsigned bsr_num;      /* bsr id number for its type */
	int      bsr_minor;

	struct list_head bsr_list;

	dev_t    bsr_dev;
	struct cdev bsr_cdev;
	struct device *bsr_device;
	char     bsr_name[32];

};

static unsigned total_bsr_devs;
static struct list_head bsr_devs = LIST_HEAD_INIT(bsr_devs);
static struct class *bsr_class;
static int bsr_major;

enum {
	BSR_8    = 0,
	BSR_16   = 1,
	BSR_64   = 2,
	BSR_128  = 3,
	BSR_4096 = 4,
	BSR_UNKNOWN = 5,
	BSR_MAX  = 6,
};

static unsigned bsr_types[BSR_MAX];

static ssize_t
bsr_size_show(struct device *dev, struct device_attribute *attr, char *buf)
{
	struct bsr_dev *bsr_dev = dev_get_drvdata(dev);
	return sprintf(buf, "%u\n", bsr_dev->bsr_bytes);
}

static ssize_t
bsr_stride_show(struct device *dev, struct device_attribute *attr, char *buf)
{
	struct bsr_dev *bsr_dev = dev_get_drvdata(dev);
	return sprintf(buf, "%u\n", bsr_dev->bsr_stride);
}

static ssize_t
bsr_len_show(struct device *dev, struct device_attribute *attr, char *buf)
{
	struct bsr_dev *bsr_dev = dev_get_drvdata(dev);
	return sprintf(buf, "%llu\n", bsr_dev->bsr_len);
}

static struct device_attribute bsr_dev_attrs[] = {
	__ATTR(bsr_size, S_IRUGO, bsr_size_show, NULL),
	__ATTR(bsr_stride, S_IRUGO, bsr_stride_show, NULL),
	__ATTR(bsr_length, S_IRUGO, bsr_len_show, NULL),
	__ATTR_NULL
};

static int bsr_mmap(struct file *filp, struct vm_area_struct *vma)
{
	unsigned long size   = vma->vm_end - vma->vm_start;
	struct bsr_dev *dev = filp->private_data;
	int ret;

	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);

	/* check for the case of a small BSR device and map one 4k page for it*/
	if (dev->bsr_len < PAGE_SIZE && size == PAGE_SIZE)
		ret = remap_4k_pfn(vma, vma->vm_start, dev->bsr_addr >> 12,
				   vma->vm_page_prot);
	else if (size <= dev->bsr_len)
		ret = io_remap_pfn_range(vma, vma->vm_start,
					 dev->bsr_addr >> PAGE_SHIFT,
					 size, vma->vm_page_prot);
	else
		return -EINVAL;

	if (ret)
		return -EAGAIN;

	return 0;
}

static int bsr_open(struct inode * inode, struct file * filp)
{
	struct cdev *cdev = inode->i_cdev;
	struct bsr_dev *dev = container_of(cdev, struct bsr_dev, bsr_cdev);

	filp->private_data = dev;
	return 0;
}

static const struct file_operations bsr_fops = {
	.owner = THIS_MODULE,
	.mmap  = bsr_mmap,
	.open  = bsr_open,
	.llseek = noop_llseek,
};

static void bsr_cleanup_devs(void)
{
	struct bsr_dev *cur, *n;

	list_for_each_entry_safe(cur, n, &bsr_devs, bsr_list) {
		if (cur->bsr_device) {
			cdev_del(&cur->bsr_cdev);
			device_del(cur->bsr_device);
		}
		list_del(&cur->bsr_list);
		kfree(cur);
	}
}

static int bsr_add_node(struct device_node *bn)
{
	int bsr_stride_len, bsr_bytes_len, num_bsr_devs;
	const u32 *bsr_stride;
	const u32 *bsr_bytes;
	unsigned i;
	int ret = -ENODEV;

	bsr_stride = of_get_property(bn, "ibm,lock-stride", &bsr_stride_len);
	bsr_bytes  = of_get_property(bn, "ibm,#lock-bytes", &bsr_bytes_len);

	if (!bsr_stride || !bsr_bytes ||
	    (bsr_stride_len != bsr_bytes_len)) {
		printk(KERN_ERR "bsr of-node has missing/incorrect property\n");
		return ret;
	}

	num_bsr_devs = bsr_bytes_len / sizeof(u32);

	for (i = 0 ; i < num_bsr_devs; i++) {
		struct bsr_dev *cur = kzalloc(sizeof(struct bsr_dev),
					      GFP_KERNEL);
		struct resource res;
		int result;

		if (!cur) {
			printk(KERN_ERR "Unable to alloc bsr dev\n");
			ret = -ENOMEM;
			goto out_err;
		}

		result = of_address_to_resource(bn, i, &res);
		if (result < 0) {
			printk(KERN_ERR "bsr of-node has invalid reg property, skipping\n");
			kfree(cur);
			continue;
		}

		cur->bsr_minor  = i + total_bsr_devs;
		cur->bsr_addr   = res.start;
		cur->bsr_len    = resource_size(&res);
		cur->bsr_bytes  = bsr_bytes[i];
		cur->bsr_stride = bsr_stride[i];
		cur->bsr_dev    = MKDEV(bsr_major, i + total_bsr_devs);

		/* if we have a bsr_len of > 4k and less then PAGE_SIZE (64k pages) */
		/* we can only map 4k of it, so only advertise the 4k in sysfs */
		if (cur->bsr_len > 4096 && cur->bsr_len < PAGE_SIZE)
			cur->bsr_len = 4096;

		switch(cur->bsr_bytes) {
		case 8:
			cur->bsr_type = BSR_8;
			break;
		case 16:
			cur->bsr_type = BSR_16;
			break;
		case 64:
			cur->bsr_type = BSR_64;
			break;
		case 128:
			cur->bsr_type = BSR_128;
			break;
		case 4096:
			cur->bsr_type = BSR_4096;
			break;
		default:
			cur->bsr_type = BSR_UNKNOWN;
		}

		cur->bsr_num = bsr_types[cur->bsr_type];
		snprintf(cur->bsr_name, 32, "bsr%d_%d",
			 cur->bsr_bytes, cur->bsr_num);

		cdev_init(&cur->bsr_cdev, &bsr_fops);
		result = cdev_add(&cur->bsr_cdev, cur->bsr_dev, 1);
		if (result) {
			kfree(cur);
			goto out_err;
		}

		cur->bsr_device = device_create(bsr_class, NULL, cur->bsr_dev,
						cur, cur->bsr_name);
		if (IS_ERR(cur->bsr_device)) {
			printk(KERN_ERR "device_create failed for %s\n",
			       cur->bsr_name);
			cdev_del(&cur->bsr_cdev);
			kfree(cur);
			goto out_err;
		}

		bsr_types[cur->bsr_type] = cur->bsr_num + 1;
		list_add_tail(&cur->bsr_list, &bsr_devs);
	}

	total_bsr_devs += num_bsr_devs;

	return 0;

 out_err:

	bsr_cleanup_devs();
	return ret;
}

static int bsr_create_devs(struct device_node *bn)
{
	int ret;

	while (bn) {
		ret = bsr_add_node(bn);
		if (ret) {
			of_node_put(bn);
			return ret;
		}
		bn = of_find_compatible_node(bn, NULL, "ibm,bsr");
	}
	return 0;
}

static int __init bsr_init(void)
{
	struct device_node *np;
	dev_t bsr_dev;
	int ret = -ENODEV;

	np = of_find_compatible_node(NULL, NULL, "ibm,bsr");
	if (!np)
		goto out_err;

	bsr_class = class_create(THIS_MODULE, "bsr");
	if (IS_ERR(bsr_class)) {
		printk(KERN_ERR "class_create() failed for bsr_class\n");
		ret = PTR_ERR(bsr_class);
		goto out_err_1;
	}
	bsr_class->dev_attrs = bsr_dev_attrs;

	ret = alloc_chrdev_region(&bsr_dev, 0, BSR_MAX_DEVS, "bsr");
	bsr_major = MAJOR(bsr_dev);
	if (ret < 0) {
		printk(KERN_ERR "alloc_chrdev_region() failed for bsr\n");
		goto out_err_2;
	}

	if ((ret = bsr_create_devs(np)) < 0) {
		np = NULL;
		goto out_err_3;
	}

	return 0;

 out_err_3:
	unregister_chrdev_region(bsr_dev, BSR_MAX_DEVS);

 out_err_2:
	class_destroy(bsr_class);

 out_err_1:
	of_node_put(np);

 out_err:

	return ret;
}

static void __exit  bsr_exit(void)
{

	bsr_cleanup_devs();

	if (bsr_class)
		class_destroy(bsr_class);

	if (bsr_major)
		unregister_chrdev_region(MKDEV(bsr_major, 0), BSR_MAX_DEVS);
}

module_init(bsr_init);
module_exit(bsr_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Sonny Rao <[email protected]>");
Commit	Line	Data
fe9e8d53 SR	1	/* IBM POWER Barrier Synchronization Register Driver
	2	*
	3	* Copyright IBM Corporation 2008
	4	*
	5	* Author: Sonny Rao <[email protected]>
	6	*
	7	* This program is free software; you can redistribute it and/or modify
	8	* it under the terms of the GNU General Public License as published by
	9	* the Free Software Foundation; either version 2 of the License, or
	10	* (at your option) any later version.
	11	*
	12	* This program is distributed in the hope that it will be useful,
	13	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	14	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	15	* GNU General Public License for more details.
	16	*
	17	* You should have received a copy of the GNU General Public License
	18	* along with this program; if not, write to the Free Software
	19	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
	20	*/
	21
	22	#include <linux/kernel.h>
	23	#include <linux/of.h>
	24	#include <linux/of_device.h>
	25	#include <linux/of_platform.h>
22ae782f	26	#include <linux/fs.h>
fe9e8d53 SR	27	#include <linux/module.h>
	28	#include <linux/cdev.h>
	29	#include <linux/list.h>
	30	#include <linux/mm.h>
5a0e3ad6	31	#include <linux/slab.h>
04a85d12	32	#include <asm/pgtable.h>
fe9e8d53 SR	33	#include <asm/io.h>
	34
	35	/*
	36	This driver exposes a special register which can be used for fast
	37	synchronization across a large SMP machine. The hardware is exposed
	38	as an array of bytes where each process will write to one of the bytes to
	39	indicate it has finished the current stage and this update is broadcast to
	40	all processors without having to bounce a cacheline between them. In
	41	POWER5 and POWER6 there is one of these registers per SMP, but it is
	42	presented in two forms; first, it is given as a whole and then as a number
	43	of smaller registers which alias to parts of the single whole register.
	44	This can potentially allow multiple groups of processes to each have their
	45	own private synchronization device.
	46
	47	Note that this hardware must be written to using only single byte writes.
	48	It may be read using 1, 2, 4, or 8 byte loads which must be aligned since
	49	this region is treated as cache-inhibited processes should also use a
	50	full sync before and after writing to the BSR to ensure all stores and
	51	the BSR update have made it to all chips in the system
	52	*/
	53
	54	/* This is arbitrary number, up to Power6 it's been 17 or fewer */
	55	#define BSR_MAX_DEVS (32)
	56
	57	struct bsr_dev {
	58	u64 bsr_addr; /* Real address */
	59	u64 bsr_len; /* length of mem region we can map */
	60	unsigned bsr_bytes; /* size of the BSR reg itself */
	61	unsigned bsr_stride; /* interval at which BSR repeats in the page */
	62	unsigned bsr_type; /* maps to enum below */
	63	unsigned bsr_num; /* bsr id number for its type */
	64	int bsr_minor;
	65
a0e2f9f4 SR	66	struct list_head bsr_list;
a0e2f9f4 SR	67
fe9e8d53 SR	68	dev_t bsr_dev;
	69	struct cdev bsr_cdev;
	70	struct device *bsr_device;
	71	char bsr_name[32];
	72
	73	};
	74
a0e2f9f4 SR	75	static unsigned total_bsr_devs;
a0e2f9f4 SR	76	static struct list_head bsr_devs = LIST_HEAD_INIT(bsr_devs);
fe9e8d53 SR	77	static struct class *bsr_class;
	78	static int bsr_major;
	79
	80	enum {
e4031d52 SR	81	BSR_8 = 0,
	82	BSR_16 = 1,
	83	BSR_64 = 2,
	84	BSR_128 = 3,
	85	BSR_4096 = 4,
	86	BSR_UNKNOWN = 5,
	87	BSR_MAX = 6,
fe9e8d53 SR	88	};
	89
	90	static unsigned bsr_types[BSR_MAX];
	91
	92	static ssize_t
	93	bsr_size_show(struct device dev, struct device_attribute attr, char *buf)
	94	{
	95	struct bsr_dev *bsr_dev = dev_get_drvdata(dev);
	96	return sprintf(buf, "%u\n", bsr_dev->bsr_bytes);
	97	}
	98
	99	static ssize_t
	100	bsr_stride_show(struct device dev, struct device_attribute attr, char *buf)
	101	{
	102	struct bsr_dev *bsr_dev = dev_get_drvdata(dev);
	103	return sprintf(buf, "%u\n", bsr_dev->bsr_stride);
	104	}
	105
	106	static ssize_t
	107	bsr_len_show(struct device dev, struct device_attribute attr, char *buf)
	108	{
	109	struct bsr_dev *bsr_dev = dev_get_drvdata(dev);
1901515c	110	return sprintf(buf, "%llu\n", bsr_dev->bsr_len);
fe9e8d53 SR	111	}
	112
	113	static struct device_attribute bsr_dev_attrs[] = {
	114	__ATTR(bsr_size, S_IRUGO, bsr_size_show, NULL),
	115	__ATTR(bsr_stride, S_IRUGO, bsr_stride_show, NULL),
	116	__ATTR(bsr_length, S_IRUGO, bsr_len_show, NULL),
	117	__ATTR_NULL
	118	};
	119
	120	static int bsr_mmap(struct file filp, struct vm_area_struct vma)
	121	{
	122	unsigned long size = vma->vm_end - vma->vm_start;
	123	struct bsr_dev *dev = filp->private_data;
04a85d12	124	int ret;
fe9e8d53	125
fe9e8d53 SR	126	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
fe9e8d53 SR	127
04a85d12 SR	128	/* check for the case of a small BSR device and map one 4k page for it*/
	129	if (dev->bsr_len < PAGE_SIZE && size == PAGE_SIZE)
	130	ret = remap_4k_pfn(vma, vma->vm_start, dev->bsr_addr >> 12,
	131	vma->vm_page_prot);
	132	else if (size <= dev->bsr_len)
	133	ret = io_remap_pfn_range(vma, vma->vm_start,
	134	dev->bsr_addr >> PAGE_SHIFT,
	135	size, vma->vm_page_prot);
	136	else
	137	return -EINVAL;
	138
	139	if (ret)
fe9e8d53 SR	140	return -EAGAIN;
	141
	142	return 0;
	143	}
	144
	145	static int bsr_open(struct inode * inode, struct file * filp)
	146	{
	147	struct cdev *cdev = inode->i_cdev;
	148	struct bsr_dev *dev = container_of(cdev, struct bsr_dev, bsr_cdev);
	149
	150	filp->private_data = dev;
	151	return 0;
	152	}
	153
27157a70	154	static const struct file_operations bsr_fops = {
fe9e8d53 SR	155	.owner = THIS_MODULE,
	156	.mmap = bsr_mmap,
	157	.open = bsr_open,
6038f373	158	.llseek = noop_llseek,
fe9e8d53 SR	159	};
	160
	161	static void bsr_cleanup_devs(void)
	162	{
a0e2f9f4 SR	163	struct bsr_dev cur, n;
	164
	165	list_for_each_entry_safe(cur, n, &bsr_devs, bsr_list) {
fe9e8d53 SR	166	if (cur->bsr_device) {
	167	cdev_del(&cur->bsr_cdev);
	168	device_del(cur->bsr_device);
	169	}
a0e2f9f4 SR	170	list_del(&cur->bsr_list);
a0e2f9f4 SR	171	kfree(cur);
fe9e8d53	172	}
fe9e8d53 SR	173	}
fe9e8d53 SR	174
a0e2f9f4	175	static int bsr_add_node(struct device_node *bn)
fe9e8d53	176	{
a0e2f9f4	177	int bsr_stride_len, bsr_bytes_len, num_bsr_devs;
fe9e8d53 SR	178	const u32 *bsr_stride;
	179	const u32 *bsr_bytes;
	180	unsigned i;
a0e2f9f4	181	int ret = -ENODEV;
fe9e8d53 SR	182
	183	bsr_stride = of_get_property(bn, "ibm,lock-stride", &bsr_stride_len);
	184	bsr_bytes = of_get_property(bn, "ibm,#lock-bytes", &bsr_bytes_len);
	185
	186	if (!bsr_stride \|\| !bsr_bytes \|\|
	187	(bsr_stride_len != bsr_bytes_len)) {
	188	printk(KERN_ERR "bsr of-node has missing/incorrect property\n");
a0e2f9f4	189	return ret;
fe9e8d53 SR	190	}
	191
	192	num_bsr_devs = bsr_bytes_len / sizeof(u32);
	193
fe9e8d53	194	for (i = 0 ; i < num_bsr_devs; i++) {
a0e2f9f4 SR	195	struct bsr_dev *cur = kzalloc(sizeof(struct bsr_dev),
a0e2f9f4 SR	196	GFP_KERNEL);
fe9e8d53 SR	197	struct resource res;
	198	int result;
	199
a0e2f9f4 SR	200	if (!cur) {
	201	printk(KERN_ERR "Unable to alloc bsr dev\n");
	202	ret = -ENOMEM;
	203	goto out_err;
	204	}
	205
fe9e8d53 SR	206	result = of_address_to_resource(bn, i, &res);
fe9e8d53 SR	207	if (result < 0) {
a0e2f9f4 SR	208	printk(KERN_ERR "bsr of-node has invalid reg property, skipping\n");
	209	kfree(cur);
	210	continue;
fe9e8d53 SR	211	}
fe9e8d53 SR	212
a0e2f9f4	213	cur->bsr_minor = i + total_bsr_devs;
fe9e8d53	214	cur->bsr_addr = res.start;
28f65c11	215	cur->bsr_len = resource_size(&res);
fe9e8d53 SR	216	cur->bsr_bytes = bsr_bytes[i];
fe9e8d53 SR	217	cur->bsr_stride = bsr_stride[i];
a0e2f9f4	218	cur->bsr_dev = MKDEV(bsr_major, i + total_bsr_devs);
fe9e8d53	219
04a85d12 SR	220	/* if we have a bsr_len of > 4k and less then PAGE_SIZE (64k pages) */
	221	/* we can only map 4k of it, so only advertise the 4k in sysfs */
	222	if (cur->bsr_len > 4096 && cur->bsr_len < PAGE_SIZE)
	223	cur->bsr_len = 4096;
	224
fe9e8d53 SR	225	switch(cur->bsr_bytes) {
	226	case 8:
	227	cur->bsr_type = BSR_8;
	228	break;
	229	case 16:
	230	cur->bsr_type = BSR_16;
	231	break;
	232	case 64:
	233	cur->bsr_type = BSR_64;
	234	break;
	235	case 128:
	236	cur->bsr_type = BSR_128;
	237	break;
e4031d52 SR	238	case 4096:
	239	cur->bsr_type = BSR_4096;
	240	break;
fe9e8d53 SR	241	default:
fe9e8d53 SR	242	cur->bsr_type = BSR_UNKNOWN;
fe9e8d53 SR	243	}
	244
	245	cur->bsr_num = bsr_types[cur->bsr_type];
fe9e8d53 SR	246	snprintf(cur->bsr_name, 32, "bsr%d_%d",
	247	cur->bsr_bytes, cur->bsr_num);
	248
	249	cdev_init(&cur->bsr_cdev, &bsr_fops);
	250	result = cdev_add(&cur->bsr_cdev, cur->bsr_dev, 1);
a0e2f9f4 SR	251	if (result) {
a0e2f9f4 SR	252	kfree(cur);
fe9e8d53	253	goto out_err;
a0e2f9f4	254	}
fe9e8d53	255
03457cd4 GKH	256	cur->bsr_device = device_create(bsr_class, NULL, cur->bsr_dev,
03457cd4 GKH	257	cur, cur->bsr_name);
30c96ce5	258	if (IS_ERR(cur->bsr_device)) {
fe9e8d53 SR	259	printk(KERN_ERR "device_create failed for %s\n",
	260	cur->bsr_name);
	261	cdev_del(&cur->bsr_cdev);
a0e2f9f4	262	kfree(cur);
fe9e8d53 SR	263	goto out_err;
fe9e8d53 SR	264	}
a0e2f9f4 SR	265
	266	bsr_types[cur->bsr_type] = cur->bsr_num + 1;
	267	list_add_tail(&cur->bsr_list, &bsr_devs);
fe9e8d53 SR	268	}
fe9e8d53 SR	269
a0e2f9f4 SR	270	total_bsr_devs += num_bsr_devs;
a0e2f9f4 SR	271
fe9e8d53 SR	272	return 0;
	273
	274	out_err:
	275
	276	bsr_cleanup_devs();
a0e2f9f4 SR	277	return ret;
	278	}
	279
	280	static int bsr_create_devs(struct device_node *bn)
	281	{
	282	int ret;
	283
	284	while (bn) {
	285	ret = bsr_add_node(bn);
	286	if (ret) {
	287	of_node_put(bn);
	288	return ret;
	289	}
	290	bn = of_find_compatible_node(bn, NULL, "ibm,bsr");
	291	}
	292	return 0;
fe9e8d53 SR	293	}
	294
	295	static int __init bsr_init(void)
	296	{
	297	struct device_node *np;
cce36444	298	dev_t bsr_dev;
fe9e8d53	299	int ret = -ENODEV;
fe9e8d53	300
a0e2f9f4	301	np = of_find_compatible_node(NULL, NULL, "ibm,bsr");
fe9e8d53 SR	302	if (!np)
	303	goto out_err;
	304
	305	bsr_class = class_create(THIS_MODULE, "bsr");
	306	if (IS_ERR(bsr_class)) {
	307	printk(KERN_ERR "class_create() failed for bsr_class\n");
8397c76a	308	ret = PTR_ERR(bsr_class);
fe9e8d53 SR	309	goto out_err_1;
	310	}
	311	bsr_class->dev_attrs = bsr_dev_attrs;
	312
8397c76a	313	ret = alloc_chrdev_region(&bsr_dev, 0, BSR_MAX_DEVS, "bsr");
fe9e8d53	314	bsr_major = MAJOR(bsr_dev);
8397c76a	315	if (ret < 0) {
fe9e8d53 SR	316	printk(KERN_ERR "alloc_chrdev_region() failed for bsr\n");
	317	goto out_err_2;
	318	}
	319
a0e2f9f4 SR	320	if ((ret = bsr_create_devs(np)) < 0) {
a0e2f9f4 SR	321	np = NULL;
fe9e8d53	322	goto out_err_3;
a0e2f9f4	323	}
fe9e8d53 SR	324
	325	return 0;
	326
	327	out_err_3:
	328	unregister_chrdev_region(bsr_dev, BSR_MAX_DEVS);
	329
	330	out_err_2:
	331	class_destroy(bsr_class);
	332
	333	out_err_1:
	334	of_node_put(np);
	335
	336	out_err:
	337
	338	return ret;
	339	}
	340
	341	static void __exit bsr_exit(void)
	342	{
	343
	344	bsr_cleanup_devs();
	345
	346	if (bsr_class)
	347	class_destroy(bsr_class);
	348
	349	if (bsr_major)
	350	unregister_chrdev_region(MKDEV(bsr_major, 0), BSR_MAX_DEVS);
	351	}
	352
	353	module_init(bsr_init);
	354	module_exit(bsr_exit);
	355	MODULE_LICENSE("GPL");
	356	MODULE_AUTHOR("Sonny Rao <[email protected]>");