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1/* IBM POWER Barrier Synchronization Register Driver
2 *
3 * Copyright IBM Corporation 2008
4 *
5 * Author: Sonny Rao <sonnyrao@us.ibm.com>
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_address.h>
25#include <linux/of_device.h>
26#include <linux/of_platform.h>
27#include <linux/fs.h>
28#include <linux/module.h>
29#include <linux/cdev.h>
30#include <linux/list.h>
31#include <linux/mm.h>
32#include <linux/slab.h>
33#include <asm/pgtable.h>
34#include <asm/io.h>
35
36/*
37 This driver exposes a special register which can be used for fast
38 synchronization across a large SMP machine. The hardware is exposed
39 as an array of bytes where each process will write to one of the bytes to
40 indicate it has finished the current stage and this update is broadcast to
41 all processors without having to bounce a cacheline between them. In
42 POWER5 and POWER6 there is one of these registers per SMP, but it is
43 presented in two forms; first, it is given as a whole and then as a number
44 of smaller registers which alias to parts of the single whole register.
45 This can potentially allow multiple groups of processes to each have their
46 own private synchronization device.
47
48 Note that this hardware *must* be written to using *only* single byte writes.
49 It may be read using 1, 2, 4, or 8 byte loads which must be aligned since
50 this region is treated as cache-inhibited processes should also use a
51 full sync before and after writing to the BSR to ensure all stores and
52 the BSR update have made it to all chips in the system
53*/
54
55/* This is arbitrary number, up to Power6 it's been 17 or fewer */
56#define BSR_MAX_DEVS (32)
57
58struct bsr_dev {
59 u64 bsr_addr; /* Real address */
60 u64 bsr_len; /* length of mem region we can map */
61 unsigned bsr_bytes; /* size of the BSR reg itself */
62 unsigned bsr_stride; /* interval at which BSR repeats in the page */
63 unsigned bsr_type; /* maps to enum below */
64 unsigned bsr_num; /* bsr id number for its type */
65 int bsr_minor;
66
67 struct list_head bsr_list;
68
69 dev_t bsr_dev;
70 struct cdev bsr_cdev;
71 struct device *bsr_device;
72 char bsr_name[32];
73
74};
75
76static unsigned total_bsr_devs;
77static struct list_head bsr_devs = LIST_HEAD_INIT(bsr_devs);
78static struct class *bsr_class;
79static int bsr_major;
80
81enum {
82 BSR_8 = 0,
83 BSR_16 = 1,
84 BSR_64 = 2,
85 BSR_128 = 3,
86 BSR_4096 = 4,
87 BSR_UNKNOWN = 5,
88 BSR_MAX = 6,
89};
90
91static unsigned bsr_types[BSR_MAX];
92
93static ssize_t
94bsr_size_show(struct device *dev, struct device_attribute *attr, char *buf)
95{
96 struct bsr_dev *bsr_dev = dev_get_drvdata(dev);
97 return sprintf(buf, "%u\n", bsr_dev->bsr_bytes);
98}
99static DEVICE_ATTR_RO(bsr_size);
100
101static ssize_t
102bsr_stride_show(struct device *dev, struct device_attribute *attr, char *buf)
103{
104 struct bsr_dev *bsr_dev = dev_get_drvdata(dev);
105 return sprintf(buf, "%u\n", bsr_dev->bsr_stride);
106}
107static DEVICE_ATTR_RO(bsr_stride);
108
109static ssize_t
110bsr_length_show(struct device *dev, struct device_attribute *attr, char *buf)
111{
112 struct bsr_dev *bsr_dev = dev_get_drvdata(dev);
113 return sprintf(buf, "%llu\n", bsr_dev->bsr_len);
114}
115static DEVICE_ATTR_RO(bsr_length);
116
117static struct attribute *bsr_dev_attrs[] = {
118 &dev_attr_bsr_size.attr,
119 &dev_attr_bsr_stride.attr,
120 &dev_attr_bsr_length.attr,
121 NULL,
122};
123ATTRIBUTE_GROUPS(bsr_dev);
124
125static int bsr_mmap(struct file *filp, struct vm_area_struct *vma)
126{
127 unsigned long size = vma->vm_end - vma->vm_start;
128 struct bsr_dev *dev = filp->private_data;
129 int ret;
130
131 vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
132
133 /* check for the case of a small BSR device and map one 4k page for it*/
134 if (dev->bsr_len < PAGE_SIZE && size == PAGE_SIZE)
135 ret = remap_4k_pfn(vma, vma->vm_start, dev->bsr_addr >> 12,
136 vma->vm_page_prot);
137 else if (size <= dev->bsr_len)
138 ret = io_remap_pfn_range(vma, vma->vm_start,
139 dev->bsr_addr >> PAGE_SHIFT,
140 size, vma->vm_page_prot);
141 else
142 return -EINVAL;
143
144 if (ret)
145 return -EAGAIN;
146
147 return 0;
148}
149
150static int bsr_open(struct inode * inode, struct file * filp)
151{
152 struct cdev *cdev = inode->i_cdev;
153 struct bsr_dev *dev = container_of(cdev, struct bsr_dev, bsr_cdev);
154
155 filp->private_data = dev;
156 return 0;
157}
158
159static const struct file_operations bsr_fops = {
160 .owner = THIS_MODULE,
161 .mmap = bsr_mmap,
162 .open = bsr_open,
163 .llseek = noop_llseek,
164};
165
166static void bsr_cleanup_devs(void)
167{
168 struct bsr_dev *cur, *n;
169
170 list_for_each_entry_safe(cur, n, &bsr_devs, bsr_list) {
171 if (cur->bsr_device) {
172 cdev_del(&cur->bsr_cdev);
173 device_del(cur->bsr_device);
174 }
175 list_del(&cur->bsr_list);
176 kfree(cur);
177 }
178}
179
180static int bsr_add_node(struct device_node *bn)
181{
182 int bsr_stride_len, bsr_bytes_len, num_bsr_devs;
183 const u32 *bsr_stride;
184 const u32 *bsr_bytes;
185 unsigned i;
186 int ret = -ENODEV;
187
188 bsr_stride = of_get_property(bn, "ibm,lock-stride", &bsr_stride_len);
189 bsr_bytes = of_get_property(bn, "ibm,#lock-bytes", &bsr_bytes_len);
190
191 if (!bsr_stride || !bsr_bytes ||
192 (bsr_stride_len != bsr_bytes_len)) {
193 printk(KERN_ERR "bsr of-node has missing/incorrect property\n");
194 return ret;
195 }
196
197 num_bsr_devs = bsr_bytes_len / sizeof(u32);
198
199 for (i = 0 ; i < num_bsr_devs; i++) {
200 struct bsr_dev *cur = kzalloc(sizeof(struct bsr_dev),
201 GFP_KERNEL);
202 struct resource res;
203 int result;
204
205 if (!cur) {
206 printk(KERN_ERR "Unable to alloc bsr dev\n");
207 ret = -ENOMEM;
208 goto out_err;
209 }
210
211 result = of_address_to_resource(bn, i, &res);
212 if (result < 0) {
213 printk(KERN_ERR "bsr of-node has invalid reg property, skipping\n");
214 kfree(cur);
215 continue;
216 }
217
218 cur->bsr_minor = i + total_bsr_devs;
219 cur->bsr_addr = res.start;
220 cur->bsr_len = resource_size(&res);
221 cur->bsr_bytes = bsr_bytes[i];
222 cur->bsr_stride = bsr_stride[i];
223 cur->bsr_dev = MKDEV(bsr_major, i + total_bsr_devs);
224
225 /* if we have a bsr_len of > 4k and less then PAGE_SIZE (64k pages) */
226 /* we can only map 4k of it, so only advertise the 4k in sysfs */
227 if (cur->bsr_len > 4096 && cur->bsr_len < PAGE_SIZE)
228 cur->bsr_len = 4096;
229
230 switch(cur->bsr_bytes) {
231 case 8:
232 cur->bsr_type = BSR_8;
233 break;
234 case 16:
235 cur->bsr_type = BSR_16;
236 break;
237 case 64:
238 cur->bsr_type = BSR_64;
239 break;
240 case 128:
241 cur->bsr_type = BSR_128;
242 break;
243 case 4096:
244 cur->bsr_type = BSR_4096;
245 break;
246 default:
247 cur->bsr_type = BSR_UNKNOWN;
248 }
249
250 cur->bsr_num = bsr_types[cur->bsr_type];
251 snprintf(cur->bsr_name, 32, "bsr%d_%d",
252 cur->bsr_bytes, cur->bsr_num);
253
254 cdev_init(&cur->bsr_cdev, &bsr_fops);
255 result = cdev_add(&cur->bsr_cdev, cur->bsr_dev, 1);
256 if (result) {
257 kfree(cur);
258 goto out_err;
259 }
260
261 cur->bsr_device = device_create(bsr_class, NULL, cur->bsr_dev,
262 cur, "%s", cur->bsr_name);
263 if (IS_ERR(cur->bsr_device)) {
264 printk(KERN_ERR "device_create failed for %s\n",
265 cur->bsr_name);
266 cdev_del(&cur->bsr_cdev);
267 kfree(cur);
268 goto out_err;
269 }
270
271 bsr_types[cur->bsr_type] = cur->bsr_num + 1;
272 list_add_tail(&cur->bsr_list, &bsr_devs);
273 }
274
275 total_bsr_devs += num_bsr_devs;
276
277 return 0;
278
279 out_err:
280
281 bsr_cleanup_devs();
282 return ret;
283}
284
285static int bsr_create_devs(struct device_node *bn)
286{
287 int ret;
288
289 while (bn) {
290 ret = bsr_add_node(bn);
291 if (ret) {
292 of_node_put(bn);
293 return ret;
294 }
295 bn = of_find_compatible_node(bn, NULL, "ibm,bsr");
296 }
297 return 0;
298}
299
300static int __init bsr_init(void)
301{
302 struct device_node *np;
303 dev_t bsr_dev;
304 int ret = -ENODEV;
305
306 np = of_find_compatible_node(NULL, NULL, "ibm,bsr");
307 if (!np)
308 goto out_err;
309
310 bsr_class = class_create(THIS_MODULE, "bsr");
311 if (IS_ERR(bsr_class)) {
312 printk(KERN_ERR "class_create() failed for bsr_class\n");
313 ret = PTR_ERR(bsr_class);
314 goto out_err_1;
315 }
316 bsr_class->dev_groups = bsr_dev_groups;
317
318 ret = alloc_chrdev_region(&bsr_dev, 0, BSR_MAX_DEVS, "bsr");
319 bsr_major = MAJOR(bsr_dev);
320 if (ret < 0) {
321 printk(KERN_ERR "alloc_chrdev_region() failed for bsr\n");
322 goto out_err_2;
323 }
324
325 if ((ret = bsr_create_devs(np)) < 0) {
326 np = NULL;
327 goto out_err_3;
328 }
329
330 return 0;
331
332 out_err_3:
333 unregister_chrdev_region(bsr_dev, BSR_MAX_DEVS);
334
335 out_err_2:
336 class_destroy(bsr_class);
337
338 out_err_1:
339 of_node_put(np);
340
341 out_err:
342
343 return ret;
344}
345
346static void __exit bsr_exit(void)
347{
348
349 bsr_cleanup_devs();
350
351 if (bsr_class)
352 class_destroy(bsr_class);
353
354 if (bsr_major)
355 unregister_chrdev_region(MKDEV(bsr_major, 0), BSR_MAX_DEVS);
356}
357
358module_init(bsr_init);
359module_exit(bsr_exit);
360MODULE_LICENSE("GPL");
361MODULE_AUTHOR("Sonny Rao <sonnyrao@us.ibm.com>");
1// SPDX-License-Identifier: GPL-2.0-or-later
2/* IBM POWER Barrier Synchronization Register Driver
3 *
4 * Copyright IBM Corporation 2008
5 *
6 * Author: Sonny Rao <sonnyrao@us.ibm.com>
7 */
8
9#include <linux/kernel.h>
10#include <linux/of.h>
11#include <linux/of_address.h>
12#include <linux/of_device.h>
13#include <linux/of_platform.h>
14#include <linux/fs.h>
15#include <linux/module.h>
16#include <linux/cdev.h>
17#include <linux/list.h>
18#include <linux/mm.h>
19#include <linux/slab.h>
20#include <asm/pgtable.h>
21#include <asm/io.h>
22
23/*
24 This driver exposes a special register which can be used for fast
25 synchronization across a large SMP machine. The hardware is exposed
26 as an array of bytes where each process will write to one of the bytes to
27 indicate it has finished the current stage and this update is broadcast to
28 all processors without having to bounce a cacheline between them. In
29 POWER5 and POWER6 there is one of these registers per SMP, but it is
30 presented in two forms; first, it is given as a whole and then as a number
31 of smaller registers which alias to parts of the single whole register.
32 This can potentially allow multiple groups of processes to each have their
33 own private synchronization device.
34
35 Note that this hardware *must* be written to using *only* single byte writes.
36 It may be read using 1, 2, 4, or 8 byte loads which must be aligned since
37 this region is treated as cache-inhibited processes should also use a
38 full sync before and after writing to the BSR to ensure all stores and
39 the BSR update have made it to all chips in the system
40*/
41
42/* This is arbitrary number, up to Power6 it's been 17 or fewer */
43#define BSR_MAX_DEVS (32)
44
45struct bsr_dev {
46 u64 bsr_addr; /* Real address */
47 u64 bsr_len; /* length of mem region we can map */
48 unsigned bsr_bytes; /* size of the BSR reg itself */
49 unsigned bsr_stride; /* interval at which BSR repeats in the page */
50 unsigned bsr_type; /* maps to enum below */
51 unsigned bsr_num; /* bsr id number for its type */
52 int bsr_minor;
53
54 struct list_head bsr_list;
55
56 dev_t bsr_dev;
57 struct cdev bsr_cdev;
58 struct device *bsr_device;
59 char bsr_name[32];
60
61};
62
63static unsigned total_bsr_devs;
64static struct list_head bsr_devs = LIST_HEAD_INIT(bsr_devs);
65static struct class *bsr_class;
66static int bsr_major;
67
68enum {
69 BSR_8 = 0,
70 BSR_16 = 1,
71 BSR_64 = 2,
72 BSR_128 = 3,
73 BSR_4096 = 4,
74 BSR_UNKNOWN = 5,
75 BSR_MAX = 6,
76};
77
78static unsigned bsr_types[BSR_MAX];
79
80static ssize_t
81bsr_size_show(struct device *dev, struct device_attribute *attr, char *buf)
82{
83 struct bsr_dev *bsr_dev = dev_get_drvdata(dev);
84 return sprintf(buf, "%u\n", bsr_dev->bsr_bytes);
85}
86static DEVICE_ATTR_RO(bsr_size);
87
88static ssize_t
89bsr_stride_show(struct device *dev, struct device_attribute *attr, char *buf)
90{
91 struct bsr_dev *bsr_dev = dev_get_drvdata(dev);
92 return sprintf(buf, "%u\n", bsr_dev->bsr_stride);
93}
94static DEVICE_ATTR_RO(bsr_stride);
95
96static ssize_t
97bsr_length_show(struct device *dev, struct device_attribute *attr, char *buf)
98{
99 struct bsr_dev *bsr_dev = dev_get_drvdata(dev);
100 return sprintf(buf, "%llu\n", bsr_dev->bsr_len);
101}
102static DEVICE_ATTR_RO(bsr_length);
103
104static struct attribute *bsr_dev_attrs[] = {
105 &dev_attr_bsr_size.attr,
106 &dev_attr_bsr_stride.attr,
107 &dev_attr_bsr_length.attr,
108 NULL,
109};
110ATTRIBUTE_GROUPS(bsr_dev);
111
112static int bsr_mmap(struct file *filp, struct vm_area_struct *vma)
113{
114 unsigned long size = vma->vm_end - vma->vm_start;
115 struct bsr_dev *dev = filp->private_data;
116 int ret;
117
118 vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
119
120 /* check for the case of a small BSR device and map one 4k page for it*/
121 if (dev->bsr_len < PAGE_SIZE && size == PAGE_SIZE)
122 ret = remap_4k_pfn(vma, vma->vm_start, dev->bsr_addr >> 12,
123 vma->vm_page_prot);
124 else if (size <= dev->bsr_len)
125 ret = io_remap_pfn_range(vma, vma->vm_start,
126 dev->bsr_addr >> PAGE_SHIFT,
127 size, vma->vm_page_prot);
128 else
129 return -EINVAL;
130
131 if (ret)
132 return -EAGAIN;
133
134 return 0;
135}
136
137static int bsr_open(struct inode *inode, struct file *filp)
138{
139 struct cdev *cdev = inode->i_cdev;
140 struct bsr_dev *dev = container_of(cdev, struct bsr_dev, bsr_cdev);
141
142 filp->private_data = dev;
143 return 0;
144}
145
146static const struct file_operations bsr_fops = {
147 .owner = THIS_MODULE,
148 .mmap = bsr_mmap,
149 .open = bsr_open,
150 .llseek = noop_llseek,
151};
152
153static void bsr_cleanup_devs(void)
154{
155 struct bsr_dev *cur, *n;
156
157 list_for_each_entry_safe(cur, n, &bsr_devs, bsr_list) {
158 if (cur->bsr_device) {
159 cdev_del(&cur->bsr_cdev);
160 device_del(cur->bsr_device);
161 }
162 list_del(&cur->bsr_list);
163 kfree(cur);
164 }
165}
166
167static int bsr_add_node(struct device_node *bn)
168{
169 int bsr_stride_len, bsr_bytes_len, num_bsr_devs;
170 const u32 *bsr_stride;
171 const u32 *bsr_bytes;
172 unsigned i;
173 int ret = -ENODEV;
174
175 bsr_stride = of_get_property(bn, "ibm,lock-stride", &bsr_stride_len);
176 bsr_bytes = of_get_property(bn, "ibm,#lock-bytes", &bsr_bytes_len);
177
178 if (!bsr_stride || !bsr_bytes ||
179 (bsr_stride_len != bsr_bytes_len)) {
180 printk(KERN_ERR "bsr of-node has missing/incorrect property\n");
181 return ret;
182 }
183
184 num_bsr_devs = bsr_bytes_len / sizeof(u32);
185
186 for (i = 0 ; i < num_bsr_devs; i++) {
187 struct bsr_dev *cur = kzalloc(sizeof(struct bsr_dev),
188 GFP_KERNEL);
189 struct resource res;
190 int result;
191
192 if (!cur) {
193 printk(KERN_ERR "Unable to alloc bsr dev\n");
194 ret = -ENOMEM;
195 goto out_err;
196 }
197
198 result = of_address_to_resource(bn, i, &res);
199 if (result < 0) {
200 printk(KERN_ERR "bsr of-node has invalid reg property, skipping\n");
201 kfree(cur);
202 continue;
203 }
204
205 cur->bsr_minor = i + total_bsr_devs;
206 cur->bsr_addr = res.start;
207 cur->bsr_len = resource_size(&res);
208 cur->bsr_bytes = bsr_bytes[i];
209 cur->bsr_stride = bsr_stride[i];
210 cur->bsr_dev = MKDEV(bsr_major, i + total_bsr_devs);
211
212 /* if we have a bsr_len of > 4k and less then PAGE_SIZE (64k pages) */
213 /* we can only map 4k of it, so only advertise the 4k in sysfs */
214 if (cur->bsr_len > 4096 && cur->bsr_len < PAGE_SIZE)
215 cur->bsr_len = 4096;
216
217 switch(cur->bsr_bytes) {
218 case 8:
219 cur->bsr_type = BSR_8;
220 break;
221 case 16:
222 cur->bsr_type = BSR_16;
223 break;
224 case 64:
225 cur->bsr_type = BSR_64;
226 break;
227 case 128:
228 cur->bsr_type = BSR_128;
229 break;
230 case 4096:
231 cur->bsr_type = BSR_4096;
232 break;
233 default:
234 cur->bsr_type = BSR_UNKNOWN;
235 }
236
237 cur->bsr_num = bsr_types[cur->bsr_type];
238 snprintf(cur->bsr_name, 32, "bsr%d_%d",
239 cur->bsr_bytes, cur->bsr_num);
240
241 cdev_init(&cur->bsr_cdev, &bsr_fops);
242 result = cdev_add(&cur->bsr_cdev, cur->bsr_dev, 1);
243 if (result) {
244 kfree(cur);
245 goto out_err;
246 }
247
248 cur->bsr_device = device_create(bsr_class, NULL, cur->bsr_dev,
249 cur, "%s", cur->bsr_name);
250 if (IS_ERR(cur->bsr_device)) {
251 printk(KERN_ERR "device_create failed for %s\n",
252 cur->bsr_name);
253 cdev_del(&cur->bsr_cdev);
254 kfree(cur);
255 goto out_err;
256 }
257
258 bsr_types[cur->bsr_type] = cur->bsr_num + 1;
259 list_add_tail(&cur->bsr_list, &bsr_devs);
260 }
261
262 total_bsr_devs += num_bsr_devs;
263
264 return 0;
265
266 out_err:
267
268 bsr_cleanup_devs();
269 return ret;
270}
271
272static int bsr_create_devs(struct device_node *bn)
273{
274 int ret;
275
276 while (bn) {
277 ret = bsr_add_node(bn);
278 if (ret) {
279 of_node_put(bn);
280 return ret;
281 }
282 bn = of_find_compatible_node(bn, NULL, "ibm,bsr");
283 }
284 return 0;
285}
286
287static int __init bsr_init(void)
288{
289 struct device_node *np;
290 dev_t bsr_dev;
291 int ret = -ENODEV;
292
293 np = of_find_compatible_node(NULL, NULL, "ibm,bsr");
294 if (!np)
295 goto out_err;
296
297 bsr_class = class_create(THIS_MODULE, "bsr");
298 if (IS_ERR(bsr_class)) {
299 printk(KERN_ERR "class_create() failed for bsr_class\n");
300 ret = PTR_ERR(bsr_class);
301 goto out_err_1;
302 }
303 bsr_class->dev_groups = bsr_dev_groups;
304
305 ret = alloc_chrdev_region(&bsr_dev, 0, BSR_MAX_DEVS, "bsr");
306 bsr_major = MAJOR(bsr_dev);
307 if (ret < 0) {
308 printk(KERN_ERR "alloc_chrdev_region() failed for bsr\n");
309 goto out_err_2;
310 }
311
312 ret = bsr_create_devs(np);
313 if (ret < 0) {
314 np = NULL;
315 goto out_err_3;
316 }
317
318 return 0;
319
320 out_err_3:
321 unregister_chrdev_region(bsr_dev, BSR_MAX_DEVS);
322
323 out_err_2:
324 class_destroy(bsr_class);
325
326 out_err_1:
327 of_node_put(np);
328
329 out_err:
330
331 return ret;
332}
333
334static void __exit bsr_exit(void)
335{
336
337 bsr_cleanup_devs();
338
339 if (bsr_class)
340 class_destroy(bsr_class);
341
342 if (bsr_major)
343 unregister_chrdev_region(MKDEV(bsr_major, 0), BSR_MAX_DEVS);
344}
345
346module_init(bsr_init);
347module_exit(bsr_exit);
348MODULE_LICENSE("GPL");
349MODULE_AUTHOR("Sonny Rao <sonnyrao@us.ibm.com>");