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authorStefano Panella <stefano.panella@csr.com>2008-12-12 08:00:06 -0500
committerDavid Vrabel <david.vrabel@csr.com>2008-12-12 08:00:06 -0500
commit5b37717a23b8e40f6cf7ad85a26ddcf41c171e2c (patch)
tree3c611f907bc61c6e1900c4092e8f2f1e8eefd907 /drivers/uwb/allocator.c
parentc35fa3ea1ae8198bd65c2c6e59d9ebd68c115a59 (diff)
uwb: improved MAS allocator and reservation conflict handling
Greatly enhance the MAS allocator: - Handle row and column reservations. - Permit all the available MAS to be allocated. - Follows the WiMedia rules on MAS selection. Take appropriate action when reservation conflicts are detected. - Correctly identify which reservation wins the conflict. - Protect alien BP reservations. - If an owned reservation loses, resize/move it. - Follow the backoff procedure before requesting additional MAS. When reservations are terminated, move the remaining reservations (if necessary) so they keep following the MAS allocation rules. Signed-off-by: Stefano Panella <stefano.panella@csr.com> Signed-off-by: David Vrabel <david.vrabel@csr.com>
Diffstat (limited to 'drivers/uwb/allocator.c')
-rw-r--r--drivers/uwb/allocator.c386
1 files changed, 386 insertions, 0 deletions
diff --git a/drivers/uwb/allocator.c b/drivers/uwb/allocator.c
new file mode 100644
index 000000000000..c8185e6b0cd5
--- /dev/null
+++ b/drivers/uwb/allocator.c
@@ -0,0 +1,386 @@
1/*
2 * UWB reservation management.
3 *
4 * Copyright (C) 2008 Cambridge Silicon Radio Ltd.
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License version
8 * 2 as published by the Free Software Foundation.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program. If not, see <http://www.gnu.org/licenses/>.
17 */
18#include <linux/version.h>
19#include <linux/kernel.h>
20#include <linux/uwb.h>
21
22#include "uwb-internal.h"
23
24static void uwb_rsv_fill_column_alloc(struct uwb_rsv_alloc_info *ai)
25{
26 int col, mas, safe_mas, unsafe_mas;
27 unsigned char *bm = ai->bm;
28 struct uwb_rsv_col_info *ci = ai->ci;
29 unsigned char c;
30
31 for (col = ci->csi.start_col; col < UWB_NUM_ZONES; col += ci->csi.interval) {
32
33 safe_mas = ci->csi.safe_mas_per_col;
34 unsafe_mas = ci->csi.unsafe_mas_per_col;
35
36 for (mas = 0; mas < UWB_MAS_PER_ZONE; mas++ ) {
37 if (bm[col * UWB_MAS_PER_ZONE + mas] == 0) {
38
39 if (safe_mas > 0) {
40 safe_mas--;
41 c = UWB_RSV_MAS_SAFE;
42 } else if (unsafe_mas > 0) {
43 unsafe_mas--;
44 c = UWB_RSV_MAS_UNSAFE;
45 } else {
46 break;
47 }
48 bm[col * UWB_MAS_PER_ZONE + mas] = c;
49 }
50 }
51 }
52}
53
54static void uwb_rsv_fill_row_alloc(struct uwb_rsv_alloc_info *ai)
55{
56 int mas, col, rows;
57 unsigned char *bm = ai->bm;
58 struct uwb_rsv_row_info *ri = &ai->ri;
59 unsigned char c;
60
61 rows = 1;
62 c = UWB_RSV_MAS_SAFE;
63 for (mas = UWB_MAS_PER_ZONE - 1; mas >= 0; mas--) {
64 if (ri->avail[mas] == 1) {
65
66 if (rows > ri->used_rows) {
67 break;
68 } else if (rows > 7) {
69 c = UWB_RSV_MAS_UNSAFE;
70 }
71
72 for (col = 0; col < UWB_NUM_ZONES; col++) {
73 if (bm[col * UWB_NUM_ZONES + mas] != UWB_RSV_MAS_NOT_AVAIL) {
74 bm[col * UWB_NUM_ZONES + mas] = c;
75 if(c == UWB_RSV_MAS_SAFE)
76 ai->safe_allocated_mases++;
77 else
78 ai->unsafe_allocated_mases++;
79 }
80 }
81 rows++;
82 }
83 }
84 ai->total_allocated_mases = ai->safe_allocated_mases + ai->unsafe_allocated_mases;
85}
86
87/*
88 * Find the best column set for a given availability, interval, num safe mas and
89 * num unsafe mas.
90 *
91 * The different sets are tried in order as shown below, depending on the interval.
92 *
93 * interval = 16
94 * deep = 0
95 * set 1 -> { 8 }
96 * deep = 1
97 * set 1 -> { 4 }
98 * set 2 -> { 12 }
99 * deep = 2
100 * set 1 -> { 2 }
101 * set 2 -> { 6 }
102 * set 3 -> { 10 }
103 * set 4 -> { 14 }
104 * deep = 3
105 * set 1 -> { 1 }
106 * set 2 -> { 3 }
107 * set 3 -> { 5 }
108 * set 4 -> { 7 }
109 * set 5 -> { 9 }
110 * set 6 -> { 11 }
111 * set 7 -> { 13 }
112 * set 8 -> { 15 }
113 *
114 * interval = 8
115 * deep = 0
116 * set 1 -> { 4 12 }
117 * deep = 1
118 * set 1 -> { 2 10 }
119 * set 2 -> { 6 14 }
120 * deep = 2
121 * set 1 -> { 1 9 }
122 * set 2 -> { 3 11 }
123 * set 3 -> { 5 13 }
124 * set 4 -> { 7 15 }
125 *
126 * interval = 4
127 * deep = 0
128 * set 1 -> { 2 6 10 14 }
129 * deep = 1
130 * set 1 -> { 1 5 9 13 }
131 * set 2 -> { 3 7 11 15 }
132 *
133 * interval = 2
134 * deep = 0
135 * set 1 -> { 1 3 5 7 9 11 13 15 }
136 */
137static int uwb_rsv_find_best_column_set(struct uwb_rsv_alloc_info *ai, int interval,
138 int num_safe_mas, int num_unsafe_mas)
139{
140 struct uwb_rsv_col_info *ci = ai->ci;
141 struct uwb_rsv_col_set_info *csi = &ci->csi;
142 struct uwb_rsv_col_set_info tmp_csi;
143 int deep, set, col, start_col_deep, col_start_set;
144 int start_col, max_mas_in_set, lowest_max_mas_in_deep;
145 int n_mas;
146 int found = UWB_RSV_ALLOC_NOT_FOUND;
147
148 tmp_csi.start_col = 0;
149 start_col_deep = interval;
150 n_mas = num_unsafe_mas + num_safe_mas;
151
152 for (deep = 0; ((interval >> deep) & 0x1) == 0; deep++) {
153 start_col_deep /= 2;
154 col_start_set = 0;
155 lowest_max_mas_in_deep = UWB_MAS_PER_ZONE;
156
157 for (set = 1; set <= (1 << deep); set++) {
158 max_mas_in_set = 0;
159 start_col = start_col_deep + col_start_set;
160 for (col = start_col; col < UWB_NUM_ZONES; col += interval) {
161
162 if (ci[col].max_avail_safe >= num_safe_mas &&
163 ci[col].max_avail_unsafe >= n_mas) {
164 if (ci[col].highest_mas[n_mas] > max_mas_in_set)
165 max_mas_in_set = ci[col].highest_mas[n_mas];
166 } else {
167 max_mas_in_set = 0;
168 break;
169 }
170 }
171 if ((lowest_max_mas_in_deep > max_mas_in_set) && max_mas_in_set) {
172 lowest_max_mas_in_deep = max_mas_in_set;
173
174 tmp_csi.start_col = start_col;
175 }
176 col_start_set += (interval >> deep);
177 }
178
179 if (lowest_max_mas_in_deep < 8) {
180 csi->start_col = tmp_csi.start_col;
181 found = UWB_RSV_ALLOC_FOUND;
182 break;
183 } else if ((lowest_max_mas_in_deep > 8) &&
184 (lowest_max_mas_in_deep != UWB_MAS_PER_ZONE) &&
185 (found == UWB_RSV_ALLOC_NOT_FOUND)) {
186 csi->start_col = tmp_csi.start_col;
187 found = UWB_RSV_ALLOC_FOUND;
188 }
189 }
190
191 if (found == UWB_RSV_ALLOC_FOUND) {
192 csi->interval = interval;
193 csi->safe_mas_per_col = num_safe_mas;
194 csi->unsafe_mas_per_col = num_unsafe_mas;
195
196 ai->safe_allocated_mases = (UWB_NUM_ZONES / interval) * num_safe_mas;
197 ai->unsafe_allocated_mases = (UWB_NUM_ZONES / interval) * num_unsafe_mas;
198 ai->total_allocated_mases = ai->safe_allocated_mases + ai->unsafe_allocated_mases;
199 ai->interval = interval;
200 }
201 return found;
202}
203
204static void get_row_descriptors(struct uwb_rsv_alloc_info *ai)
205{
206 unsigned char *bm = ai->bm;
207 struct uwb_rsv_row_info *ri = &ai->ri;
208 int col, mas;
209
210 ri->free_rows = 16;
211 for (mas = 0; mas < UWB_MAS_PER_ZONE; mas ++) {
212 ri->avail[mas] = 1;
213 for (col = 1; col < UWB_NUM_ZONES; col++) {
214 if (bm[col * UWB_NUM_ZONES + mas] == UWB_RSV_MAS_NOT_AVAIL) {
215 ri->free_rows--;
216 ri->avail[mas]=0;
217 break;
218 }
219 }
220 }
221}
222
223static void uwb_rsv_fill_column_info(unsigned char *bm, int column, struct uwb_rsv_col_info *rci)
224{
225 int mas;
226 int block_count = 0, start_block = 0;
227 int previous_avail = 0;
228 int available = 0;
229 int safe_mas_in_row[UWB_MAS_PER_ZONE] = {
230 8, 7, 6, 5, 4, 4, 4, 4, 4, 4, 4, 4, 4, 3, 2, 1,
231 };
232
233 rci->max_avail_safe = 0;
234
235 for (mas = 0; mas < UWB_MAS_PER_ZONE; mas ++) {
236 if (!bm[column * UWB_NUM_ZONES + mas]) {
237 available++;
238 rci->max_avail_unsafe = available;
239
240 rci->highest_mas[available] = mas;
241
242 if (previous_avail) {
243 block_count++;
244 if ((block_count > safe_mas_in_row[start_block]) &&
245 (!rci->max_avail_safe))
246 rci->max_avail_safe = available - 1;
247 } else {
248 previous_avail = 1;
249 start_block = mas;
250 block_count = 1;
251 }
252 } else {
253 previous_avail = 0;
254 }
255 }
256 if (!rci->max_avail_safe)
257 rci->max_avail_safe = rci->max_avail_unsafe;
258}
259
260static void get_column_descriptors(struct uwb_rsv_alloc_info *ai)
261{
262 unsigned char *bm = ai->bm;
263 struct uwb_rsv_col_info *ci = ai->ci;
264 int col;
265
266 for (col = 1; col < UWB_NUM_ZONES; col++) {
267 uwb_rsv_fill_column_info(bm, col, &ci[col]);
268 }
269}
270
271static int uwb_rsv_find_best_row_alloc(struct uwb_rsv_alloc_info *ai)
272{
273 int n_rows;
274 int max_rows = ai->max_mas / UWB_USABLE_MAS_PER_ROW;
275 int min_rows = ai->min_mas / UWB_USABLE_MAS_PER_ROW;
276 if (ai->min_mas % UWB_USABLE_MAS_PER_ROW)
277 min_rows++;
278 for (n_rows = max_rows; n_rows >= min_rows; n_rows--) {
279 if (n_rows <= ai->ri.free_rows) {
280 ai->ri.used_rows = n_rows;
281 ai->interval = 1; /* row reservation */
282 uwb_rsv_fill_row_alloc(ai);
283 return UWB_RSV_ALLOC_FOUND;
284 }
285 }
286 return UWB_RSV_ALLOC_NOT_FOUND;
287}
288
289static int uwb_rsv_find_best_col_alloc(struct uwb_rsv_alloc_info *ai, int interval)
290{
291 int n_safe, n_unsafe, n_mas;
292 int n_column = UWB_NUM_ZONES / interval;
293 int max_per_zone = ai->max_mas / n_column;
294 int min_per_zone = ai->min_mas / n_column;
295
296 if (ai->min_mas % n_column)
297 min_per_zone++;
298
299 if (min_per_zone > UWB_MAS_PER_ZONE) {
300 return UWB_RSV_ALLOC_NOT_FOUND;
301 }
302
303 if (max_per_zone > UWB_MAS_PER_ZONE) {
304 max_per_zone = UWB_MAS_PER_ZONE;
305 }
306
307 for (n_mas = max_per_zone; n_mas >= min_per_zone; n_mas--) {
308 if (uwb_rsv_find_best_column_set(ai, interval, 0, n_mas) == UWB_RSV_ALLOC_NOT_FOUND)
309 continue;
310 for (n_safe = n_mas; n_safe >= 0; n_safe--) {
311 n_unsafe = n_mas - n_safe;
312 if (uwb_rsv_find_best_column_set(ai, interval, n_safe, n_unsafe) == UWB_RSV_ALLOC_FOUND) {
313 uwb_rsv_fill_column_alloc(ai);
314 return UWB_RSV_ALLOC_FOUND;
315 }
316 }
317 }
318 return UWB_RSV_ALLOC_NOT_FOUND;
319}
320
321int uwb_rsv_find_best_allocation(struct uwb_rsv *rsv, struct uwb_mas_bm *available,
322 struct uwb_mas_bm *result)
323{
324 struct uwb_rsv_alloc_info *ai;
325 int interval;
326 int bit_index;
327
328 ai = kzalloc(sizeof(struct uwb_rsv_alloc_info), GFP_KERNEL);
329
330 ai->min_mas = rsv->min_mas;
331 ai->max_mas = rsv->max_mas;
332 ai->max_interval = rsv->max_interval;
333
334
335 /* fill the not available vector from the available bm */
336 for (bit_index = 0; bit_index < UWB_NUM_MAS; bit_index++) {
337 if (!test_bit(bit_index, available->bm))
338 ai->bm[bit_index] = UWB_RSV_MAS_NOT_AVAIL;
339 }
340
341 if (ai->max_interval == 1) {
342 get_row_descriptors(ai);
343 if (uwb_rsv_find_best_row_alloc(ai) == UWB_RSV_ALLOC_FOUND)
344 goto alloc_found;
345 else
346 goto alloc_not_found;
347 }
348
349 get_column_descriptors(ai);
350
351 for (interval = 16; interval >= 2; interval>>=1) {
352 if (interval > ai->max_interval)
353 continue;
354 if (uwb_rsv_find_best_col_alloc(ai, interval) == UWB_RSV_ALLOC_FOUND)
355 goto alloc_found;
356 }
357
358 /* try row reservation if no column is found */
359 get_row_descriptors(ai);
360 if (uwb_rsv_find_best_row_alloc(ai) == UWB_RSV_ALLOC_FOUND)
361 goto alloc_found;
362 else
363 goto alloc_not_found;
364
365 alloc_found:
366 bitmap_zero(result->bm, UWB_NUM_MAS);
367 bitmap_zero(result->unsafe_bm, UWB_NUM_MAS);
368 /* fill the safe and unsafe bitmaps */
369 for (bit_index = 0; bit_index < UWB_NUM_MAS; bit_index++) {
370 if (ai->bm[bit_index] == UWB_RSV_MAS_SAFE)
371 set_bit(bit_index, result->bm);
372 else if (ai->bm[bit_index] == UWB_RSV_MAS_UNSAFE)
373 set_bit(bit_index, result->unsafe_bm);
374 }
375 bitmap_or(result->bm, result->bm, result->unsafe_bm, UWB_NUM_MAS);
376
377 result->safe = ai->safe_allocated_mases;
378 result->unsafe = ai->unsafe_allocated_mases;
379
380 kfree(ai);
381 return UWB_RSV_ALLOC_FOUND;
382
383 alloc_not_found:
384 kfree(ai);
385 return UWB_RSV_ALLOC_NOT_FOUND;
386}
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