Root/
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_device.h> |
25 | #include <linux/of_platform.h> |
26 | #include <linux/fs.h> |
27 | #include <linux/module.h> |
28 | #include <linux/cdev.h> |
29 | #include <linux/list.h> |
30 | #include <linux/mm.h> |
31 | #include <linux/slab.h> |
32 | #include <asm/pgtable.h> |
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 | |
66 | struct list_head bsr_list; |
67 | |
68 | dev_t bsr_dev; |
69 | struct cdev bsr_cdev; |
70 | struct device *bsr_device; |
71 | char bsr_name[32]; |
72 | |
73 | }; |
74 | |
75 | static unsigned total_bsr_devs; |
76 | static struct list_head bsr_devs = LIST_HEAD_INIT(bsr_devs); |
77 | static struct class *bsr_class; |
78 | static int bsr_major; |
79 | |
80 | enum { |
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, |
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); |
110 | return sprintf(buf, "%llu\n", bsr_dev->bsr_len); |
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; |
124 | int ret; |
125 | |
126 | vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); |
127 | |
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) |
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 | |
154 | static const struct file_operations bsr_fops = { |
155 | .owner = THIS_MODULE, |
156 | .mmap = bsr_mmap, |
157 | .open = bsr_open, |
158 | .llseek = noop_llseek, |
159 | }; |
160 | |
161 | static void bsr_cleanup_devs(void) |
162 | { |
163 | struct bsr_dev *cur, *n; |
164 | |
165 | list_for_each_entry_safe(cur, n, &bsr_devs, bsr_list) { |
166 | if (cur->bsr_device) { |
167 | cdev_del(&cur->bsr_cdev); |
168 | device_del(cur->bsr_device); |
169 | } |
170 | list_del(&cur->bsr_list); |
171 | kfree(cur); |
172 | } |
173 | } |
174 | |
175 | static int bsr_add_node(struct device_node *bn) |
176 | { |
177 | int bsr_stride_len, bsr_bytes_len, num_bsr_devs; |
178 | const u32 *bsr_stride; |
179 | const u32 *bsr_bytes; |
180 | unsigned i; |
181 | int ret = -ENODEV; |
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"); |
189 | return ret; |
190 | } |
191 | |
192 | num_bsr_devs = bsr_bytes_len / sizeof(u32); |
193 | |
194 | for (i = 0 ; i < num_bsr_devs; i++) { |
195 | struct bsr_dev *cur = kzalloc(sizeof(struct bsr_dev), |
196 | GFP_KERNEL); |
197 | struct resource res; |
198 | int result; |
199 | |
200 | if (!cur) { |
201 | printk(KERN_ERR "Unable to alloc bsr dev\n"); |
202 | ret = -ENOMEM; |
203 | goto out_err; |
204 | } |
205 | |
206 | result = of_address_to_resource(bn, i, &res); |
207 | if (result < 0) { |
208 | printk(KERN_ERR "bsr of-node has invalid reg property, skipping\n"); |
209 | kfree(cur); |
210 | continue; |
211 | } |
212 | |
213 | cur->bsr_minor = i + total_bsr_devs; |
214 | cur->bsr_addr = res.start; |
215 | cur->bsr_len = resource_size(&res); |
216 | cur->bsr_bytes = bsr_bytes[i]; |
217 | cur->bsr_stride = bsr_stride[i]; |
218 | cur->bsr_dev = MKDEV(bsr_major, i + total_bsr_devs); |
219 | |
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 | |
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; |
238 | case 4096: |
239 | cur->bsr_type = BSR_4096; |
240 | break; |
241 | default: |
242 | cur->bsr_type = BSR_UNKNOWN; |
243 | } |
244 | |
245 | cur->bsr_num = bsr_types[cur->bsr_type]; |
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); |
251 | if (result) { |
252 | kfree(cur); |
253 | goto out_err; |
254 | } |
255 | |
256 | cur->bsr_device = device_create(bsr_class, NULL, cur->bsr_dev, |
257 | cur, cur->bsr_name); |
258 | if (IS_ERR(cur->bsr_device)) { |
259 | printk(KERN_ERR "device_create failed for %s\n", |
260 | cur->bsr_name); |
261 | cdev_del(&cur->bsr_cdev); |
262 | kfree(cur); |
263 | goto out_err; |
264 | } |
265 | |
266 | bsr_types[cur->bsr_type] = cur->bsr_num + 1; |
267 | list_add_tail(&cur->bsr_list, &bsr_devs); |
268 | } |
269 | |
270 | total_bsr_devs += num_bsr_devs; |
271 | |
272 | return 0; |
273 | |
274 | out_err: |
275 | |
276 | bsr_cleanup_devs(); |
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; |
293 | } |
294 | |
295 | static int __init bsr_init(void) |
296 | { |
297 | struct device_node *np; |
298 | dev_t bsr_dev; |
299 | int ret = -ENODEV; |
300 | |
301 | np = of_find_compatible_node(NULL, NULL, "ibm,bsr"); |
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"); |
308 | ret = PTR_ERR(bsr_class); |
309 | goto out_err_1; |
310 | } |
311 | bsr_class->dev_attrs = bsr_dev_attrs; |
312 | |
313 | ret = alloc_chrdev_region(&bsr_dev, 0, BSR_MAX_DEVS, "bsr"); |
314 | bsr_major = MAJOR(bsr_dev); |
315 | if (ret < 0) { |
316 | printk(KERN_ERR "alloc_chrdev_region() failed for bsr\n"); |
317 | goto out_err_2; |
318 | } |
319 | |
320 | if ((ret = bsr_create_devs(np)) < 0) { |
321 | np = NULL; |
322 | goto out_err_3; |
323 | } |
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 <sonnyrao@us.ibm.com>"); |
357 |
Branches:
ben-wpan
ben-wpan-stefan
javiroman/ks7010
jz-2.6.34
jz-2.6.34-rc5
jz-2.6.34-rc6
jz-2.6.34-rc7
jz-2.6.35
jz-2.6.36
jz-2.6.37
jz-2.6.38
jz-2.6.39
jz-3.0
jz-3.1
jz-3.11
jz-3.12
jz-3.13
jz-3.15
jz-3.16
jz-3.18-dt
jz-3.2
jz-3.3
jz-3.4
jz-3.5
jz-3.6
jz-3.6-rc2-pwm
jz-3.9
jz-3.9-clk
jz-3.9-rc8
jz47xx
jz47xx-2.6.38
master
Tags:
od-2011-09-04
od-2011-09-18
v2.6.34-rc5
v2.6.34-rc6
v2.6.34-rc7
v3.9