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1 | /* |
2 | * Ultra Wide Band |
3 | * DRP availability management |
4 | * |
5 | * Copyright (C) 2005-2006 Intel Corporation |
6 | * Reinette Chatre <reinette.chatre@intel.com> |
7 | * Copyright (C) 2008 Cambridge Silicon Radio Ltd. |
8 | * |
9 | * This program is free software; you can redistribute it and/or |
10 | * modify it under the terms of the GNU General Public License version |
11 | * 2 as published by the Free Software Foundation. |
12 | * |
13 | * This program is distributed in the hope that it will be useful, |
14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
16 | * GNU General Public License for more details. |
17 | * |
18 | * You should have received a copy of the GNU General Public License |
19 | * along with this program. If not, see <http://www.gnu.org/licenses/>. |
20 | * |
21 | * |
22 | * Manage DRP Availability (the MAS available for DRP |
23 | * reservations). Thus: |
24 | * |
25 | * - Handle DRP Availability Change notifications |
26 | * |
27 | * - Allow the reservation manager to indicate MAS reserved/released |
28 | * by local (owned by/targeted at the radio controller) |
29 | * reservations. |
30 | * |
31 | * - Based on the two sources above, generate a DRP Availability IE to |
32 | * be included in the beacon. |
33 | * |
34 | * See also the documentation for struct uwb_drp_avail. |
35 | */ |
36 | |
37 | #include <linux/errno.h> |
38 | #include <linux/module.h> |
39 | #include <linux/device.h> |
40 | #include <linux/bitmap.h> |
41 | #include "uwb-internal.h" |
42 | |
43 | /** |
44 | * uwb_drp_avail_init - initialize an RC's MAS availability |
45 | * |
46 | * All MAS are available initially. The RC will inform use which |
47 | * slots are used for the BP (it may change in size). |
48 | */ |
49 | void uwb_drp_avail_init(struct uwb_rc *rc) |
50 | { |
51 | bitmap_fill(rc->drp_avail.global, UWB_NUM_MAS); |
52 | bitmap_fill(rc->drp_avail.local, UWB_NUM_MAS); |
53 | bitmap_fill(rc->drp_avail.pending, UWB_NUM_MAS); |
54 | } |
55 | |
56 | /* |
57 | * Determine MAS available for new local reservations. |
58 | * |
59 | * avail = global & local & pending |
60 | */ |
61 | void uwb_drp_available(struct uwb_rc *rc, struct uwb_mas_bm *avail) |
62 | { |
63 | bitmap_and(avail->bm, rc->drp_avail.global, rc->drp_avail.local, UWB_NUM_MAS); |
64 | bitmap_and(avail->bm, avail->bm, rc->drp_avail.pending, UWB_NUM_MAS); |
65 | } |
66 | |
67 | /** |
68 | * uwb_drp_avail_reserve_pending - reserve MAS for a new reservation |
69 | * @rc: the radio controller |
70 | * @mas: the MAS to reserve |
71 | * |
72 | * Returns 0 on success, or -EBUSY if the MAS requested aren't available. |
73 | */ |
74 | int uwb_drp_avail_reserve_pending(struct uwb_rc *rc, struct uwb_mas_bm *mas) |
75 | { |
76 | struct uwb_mas_bm avail; |
77 | |
78 | uwb_drp_available(rc, &avail); |
79 | if (!bitmap_subset(mas->bm, avail.bm, UWB_NUM_MAS)) |
80 | return -EBUSY; |
81 | |
82 | bitmap_andnot(rc->drp_avail.pending, rc->drp_avail.pending, mas->bm, UWB_NUM_MAS); |
83 | return 0; |
84 | } |
85 | |
86 | /** |
87 | * uwb_drp_avail_reserve - reserve MAS for an established reservation |
88 | * @rc: the radio controller |
89 | * @mas: the MAS to reserve |
90 | */ |
91 | void uwb_drp_avail_reserve(struct uwb_rc *rc, struct uwb_mas_bm *mas) |
92 | { |
93 | bitmap_or(rc->drp_avail.pending, rc->drp_avail.pending, mas->bm, UWB_NUM_MAS); |
94 | bitmap_andnot(rc->drp_avail.local, rc->drp_avail.local, mas->bm, UWB_NUM_MAS); |
95 | rc->drp_avail.ie_valid = false; |
96 | } |
97 | |
98 | /** |
99 | * uwb_drp_avail_release - release MAS from a pending or established reservation |
100 | * @rc: the radio controller |
101 | * @mas: the MAS to release |
102 | */ |
103 | void uwb_drp_avail_release(struct uwb_rc *rc, struct uwb_mas_bm *mas) |
104 | { |
105 | bitmap_or(rc->drp_avail.local, rc->drp_avail.local, mas->bm, UWB_NUM_MAS); |
106 | bitmap_or(rc->drp_avail.pending, rc->drp_avail.pending, mas->bm, UWB_NUM_MAS); |
107 | rc->drp_avail.ie_valid = false; |
108 | uwb_rsv_handle_drp_avail_change(rc); |
109 | } |
110 | |
111 | /** |
112 | * uwb_drp_avail_ie_update - update the DRP Availability IE |
113 | * @rc: the radio controller |
114 | * |
115 | * avail = global & local |
116 | */ |
117 | void uwb_drp_avail_ie_update(struct uwb_rc *rc) |
118 | { |
119 | struct uwb_mas_bm avail; |
120 | |
121 | bitmap_and(avail.bm, rc->drp_avail.global, rc->drp_avail.local, UWB_NUM_MAS); |
122 | |
123 | rc->drp_avail.ie.hdr.element_id = UWB_IE_DRP_AVAILABILITY; |
124 | rc->drp_avail.ie.hdr.length = UWB_NUM_MAS / 8; |
125 | uwb_mas_bm_copy_le(rc->drp_avail.ie.bmp, &avail); |
126 | rc->drp_avail.ie_valid = true; |
127 | } |
128 | |
129 | /** |
130 | * Create an unsigned long from a buffer containing a byte stream. |
131 | * |
132 | * @array: pointer to buffer |
133 | * @itr: index of buffer from where we start |
134 | * @len: the buffer's remaining size may not be exact multiple of |
135 | * sizeof(unsigned long), @len is the length of buffer that needs |
136 | * to be converted. This will be sizeof(unsigned long) or smaller |
137 | * (BUG if not). If it is smaller then we will pad the remaining |
138 | * space of the result with zeroes. |
139 | */ |
140 | static |
141 | unsigned long get_val(u8 *array, size_t itr, size_t len) |
142 | { |
143 | unsigned long val = 0; |
144 | size_t top = itr + len; |
145 | |
146 | BUG_ON(len > sizeof(val)); |
147 | |
148 | while (itr < top) { |
149 | val <<= 8; |
150 | val |= array[top - 1]; |
151 | top--; |
152 | } |
153 | val <<= 8 * (sizeof(val) - len); /* padding */ |
154 | return val; |
155 | } |
156 | |
157 | /** |
158 | * Initialize bitmap from data buffer. |
159 | * |
160 | * The bitmap to be converted could come from a IE, for example a |
161 | * DRP Availability IE. |
162 | * From ECMA-368 1.0 [16.8.7]: " |
163 | * octets: 1 1 N * (0 to 32) |
164 | * Element ID Length (=N) DRP Availability Bitmap |
165 | * |
166 | * The DRP Availability Bitmap field is up to 256 bits long, one |
167 | * bit for each MAS in the superframe, where the least-significant |
168 | * bit of the field corresponds to the first MAS in the superframe |
169 | * and successive bits correspond to successive MASs." |
170 | * |
171 | * The DRP Availability bitmap is in octets from 0 to 32, so octet |
172 | * 32 contains bits for MAS 1-8, etc. If the bitmap is smaller than 32 |
173 | * octets, the bits in octets not included at the end of the bitmap are |
174 | * treated as zero. In this case (when the bitmap is smaller than 32 |
175 | * octets) the MAS represented range from MAS 1 to MAS (size of bitmap) |
176 | * with the last octet still containing bits for MAS 1-8, etc. |
177 | * |
178 | * For example: |
179 | * F00F0102 03040506 0708090A 0B0C0D0E 0F010203 |
180 | * ^^^^ |
181 | * |||| |
182 | * |||| |
183 | * |||\LSB of byte is MAS 9 |
184 | * ||\MSB of byte is MAS 16 |
185 | * |\LSB of first byte is MAS 1 |
186 | * \ MSB of byte is MAS 8 |
187 | * |
188 | * An example of this encoding can be found in ECMA-368 Annex-D [Table D.11] |
189 | * |
190 | * The resulting bitmap will have the following mapping: |
191 | * bit position 0 == MAS 1 |
192 | * bit position 1 == MAS 2 |
193 | * ... |
194 | * bit position (UWB_NUM_MAS - 1) == MAS UWB_NUM_MAS |
195 | * |
196 | * @bmp_itr: pointer to bitmap (can be declared with DECLARE_BITMAP) |
197 | * @buffer: pointer to buffer containing bitmap data in big endian |
198 | * format (MSB first) |
199 | * @buffer_size:number of bytes with which bitmap should be initialized |
200 | */ |
201 | static |
202 | void buffer_to_bmp(unsigned long *bmp_itr, void *_buffer, |
203 | size_t buffer_size) |
204 | { |
205 | u8 *buffer = _buffer; |
206 | size_t itr, len; |
207 | unsigned long val; |
208 | |
209 | itr = 0; |
210 | while (itr < buffer_size) { |
211 | len = buffer_size - itr >= sizeof(val) ? |
212 | sizeof(val) : buffer_size - itr; |
213 | val = get_val(buffer, itr, len); |
214 | bmp_itr[itr / sizeof(val)] = val; |
215 | itr += sizeof(val); |
216 | } |
217 | } |
218 | |
219 | |
220 | /** |
221 | * Extract DRP Availability bitmap from the notification. |
222 | * |
223 | * The notification that comes in contains a bitmap of (UWB_NUM_MAS / 8) bytes |
224 | * We convert that to our internal representation. |
225 | */ |
226 | static |
227 | int uwbd_evt_get_drp_avail(struct uwb_event *evt, unsigned long *bmp) |
228 | { |
229 | struct device *dev = &evt->rc->uwb_dev.dev; |
230 | struct uwb_rc_evt_drp_avail *drp_evt; |
231 | int result = -EINVAL; |
232 | |
233 | /* Is there enough data to decode the event? */ |
234 | if (evt->notif.size < sizeof(*drp_evt)) { |
235 | dev_err(dev, "DRP Availability Change: Not enough " |
236 | "data to decode event [%zu bytes, %zu " |
237 | "needed]\n", evt->notif.size, sizeof(*drp_evt)); |
238 | goto error; |
239 | } |
240 | drp_evt = container_of(evt->notif.rceb, struct uwb_rc_evt_drp_avail, rceb); |
241 | buffer_to_bmp(bmp, drp_evt->bmp, UWB_NUM_MAS/8); |
242 | result = 0; |
243 | error: |
244 | return result; |
245 | } |
246 | |
247 | |
248 | /** |
249 | * Process an incoming DRP Availability notification. |
250 | * |
251 | * @evt: Event information (packs the actual event data, which |
252 | * radio controller it came to, etc). |
253 | * |
254 | * @returns: 0 on success (so uwbd() frees the event buffer), < 0 |
255 | * on error. |
256 | * |
257 | * According to ECMA-368 1.0 [16.8.7], bits set to ONE indicate that |
258 | * the MAS slot is available, bits set to ZERO indicate that the slot |
259 | * is busy. |
260 | * |
261 | * So we clear available slots, we set used slots :) |
262 | * |
263 | * The notification only marks non-availability based on the BP and |
264 | * received DRP IEs that are not for this radio controller. A copy of |
265 | * this bitmap is needed to generate the real availability (which |
266 | * includes local and pending reservations). |
267 | * |
268 | * The DRP Availability IE that this radio controller emits will need |
269 | * to be updated. |
270 | */ |
271 | int uwbd_evt_handle_rc_drp_avail(struct uwb_event *evt) |
272 | { |
273 | int result; |
274 | struct uwb_rc *rc = evt->rc; |
275 | DECLARE_BITMAP(bmp, UWB_NUM_MAS); |
276 | |
277 | result = uwbd_evt_get_drp_avail(evt, bmp); |
278 | if (result < 0) |
279 | return result; |
280 | |
281 | mutex_lock(&rc->rsvs_mutex); |
282 | bitmap_copy(rc->drp_avail.global, bmp, UWB_NUM_MAS); |
283 | rc->drp_avail.ie_valid = false; |
284 | uwb_rsv_handle_drp_avail_change(rc); |
285 | mutex_unlock(&rc->rsvs_mutex); |
286 | |
287 | uwb_rsv_sched_update(rc); |
288 | |
289 | return 0; |
290 | } |
291 |
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