Add linux-next specific files for 20110831
[linux-2.6/next.git] / drivers / net / wireless / ath / hw.c
blob3f508e59f146b412246f34becab5862117bfd765
1 /*
2 * Copyright (c) 2009 Atheros Communications Inc.
4 * Permission to use, copy, modify, and/or distribute this software for any
5 * purpose with or without fee is hereby granted, provided that the above
6 * copyright notice and this permission notice appear in all copies.
8 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17 #include <asm/unaligned.h>
19 #include "ath.h"
20 #include "reg.h"
22 #define REG_READ (common->ops->read)
23 #define REG_WRITE (common->ops->write)
25 /**
26 * ath_hw_set_bssid_mask - filter out bssids we listen
28 * @common: the ath_common struct for the device.
30 * BSSID masking is a method used by AR5212 and newer hardware to inform PCU
31 * which bits of the interface's MAC address should be looked at when trying
32 * to decide which packets to ACK. In station mode and AP mode with a single
33 * BSS every bit matters since we lock to only one BSS. In AP mode with
34 * multiple BSSes (virtual interfaces) not every bit matters because hw must
35 * accept frames for all BSSes and so we tweak some bits of our mac address
36 * in order to have multiple BSSes.
38 * NOTE: This is a simple filter and does *not* filter out all
39 * relevant frames. Some frames that are not for us might get ACKed from us
40 * by PCU because they just match the mask.
42 * When handling multiple BSSes you can get the BSSID mask by computing the
43 * set of ~ ( MAC XOR BSSID ) for all bssids we handle.
45 * When you do this you are essentially computing the common bits of all your
46 * BSSes. Later it is assumed the hardware will "and" (&) the BSSID mask with
47 * the MAC address to obtain the relevant bits and compare the result with
48 * (frame's BSSID & mask) to see if they match.
50 * Simple example: on your card you have have two BSSes you have created with
51 * BSSID-01 and BSSID-02. Lets assume BSSID-01 will not use the MAC address.
52 * There is another BSSID-03 but you are not part of it. For simplicity's sake,
53 * assuming only 4 bits for a mac address and for BSSIDs you can then have:
55 * \
56 * MAC: 0001 |
57 * BSSID-01: 0100 | --> Belongs to us
58 * BSSID-02: 1001 |
59 * /
60 * -------------------
61 * BSSID-03: 0110 | --> External
62 * -------------------
64 * Our bssid_mask would then be:
66 * On loop iteration for BSSID-01:
67 * ~(0001 ^ 0100) -> ~(0101)
68 * -> 1010
69 * bssid_mask = 1010
71 * On loop iteration for BSSID-02:
72 * bssid_mask &= ~(0001 ^ 1001)
73 * bssid_mask = (1010) & ~(0001 ^ 1001)
74 * bssid_mask = (1010) & ~(1000)
75 * bssid_mask = (1010) & (0111)
76 * bssid_mask = 0010
78 * A bssid_mask of 0010 means "only pay attention to the second least
79 * significant bit". This is because its the only bit common
80 * amongst the MAC and all BSSIDs we support. To findout what the real
81 * common bit is we can simply "&" the bssid_mask now with any BSSID we have
82 * or our MAC address (we assume the hardware uses the MAC address).
84 * Now, suppose there's an incoming frame for BSSID-03:
86 * IFRAME-01: 0110
88 * An easy eye-inspeciton of this already should tell you that this frame
89 * will not pass our check. This is because the bssid_mask tells the
90 * hardware to only look at the second least significant bit and the
91 * common bit amongst the MAC and BSSIDs is 0, this frame has the 2nd LSB
92 * as 1, which does not match 0.
94 * So with IFRAME-01 we *assume* the hardware will do:
96 * allow = (IFRAME-01 & bssid_mask) == (bssid_mask & MAC) ? 1 : 0;
97 * --> allow = (0110 & 0010) == (0010 & 0001) ? 1 : 0;
98 * --> allow = (0010) == 0000 ? 1 : 0;
99 * --> allow = 0
101 * Lets now test a frame that should work:
103 * IFRAME-02: 0001 (we should allow)
105 * allow = (IFRAME-02 & bssid_mask) == (bssid_mask & MAC) ? 1 : 0;
106 * --> allow = (0001 & 0010) == (0010 & 0001) ? 1 :0;
107 * --> allow = (0000) == (0000)
108 * --> allow = 1
110 * Other examples:
112 * IFRAME-03: 0100 --> allowed
113 * IFRAME-04: 1001 --> allowed
114 * IFRAME-05: 1101 --> allowed but its not for us!!!
117 void ath_hw_setbssidmask(struct ath_common *common)
119 void *ah = common->ah;
121 REG_WRITE(ah, get_unaligned_le32(common->bssidmask), AR_BSSMSKL);
122 REG_WRITE(ah, get_unaligned_le16(common->bssidmask + 4), AR_BSSMSKU);
124 EXPORT_SYMBOL(ath_hw_setbssidmask);
128 * ath_hw_cycle_counters_update - common function to update cycle counters
130 * @common: the ath_common struct for the device.
132 * This function is used to update all cycle counters in one place.
133 * It has to be called while holding common->cc_lock!
135 void ath_hw_cycle_counters_update(struct ath_common *common)
137 u32 cycles, busy, rx, tx;
138 void *ah = common->ah;
140 /* freeze */
141 REG_WRITE(ah, AR_MIBC_FMC, AR_MIBC);
143 /* read */
144 cycles = REG_READ(ah, AR_CCCNT);
145 busy = REG_READ(ah, AR_RCCNT);
146 rx = REG_READ(ah, AR_RFCNT);
147 tx = REG_READ(ah, AR_TFCNT);
149 /* clear */
150 REG_WRITE(ah, 0, AR_CCCNT);
151 REG_WRITE(ah, 0, AR_RFCNT);
152 REG_WRITE(ah, 0, AR_RCCNT);
153 REG_WRITE(ah, 0, AR_TFCNT);
155 /* unfreeze */
156 REG_WRITE(ah, 0, AR_MIBC);
158 /* update all cycle counters here */
159 common->cc_ani.cycles += cycles;
160 common->cc_ani.rx_busy += busy;
161 common->cc_ani.rx_frame += rx;
162 common->cc_ani.tx_frame += tx;
164 common->cc_survey.cycles += cycles;
165 common->cc_survey.rx_busy += busy;
166 common->cc_survey.rx_frame += rx;
167 common->cc_survey.tx_frame += tx;
169 EXPORT_SYMBOL(ath_hw_cycle_counters_update);
171 int32_t ath_hw_get_listen_time(struct ath_common *common)
173 struct ath_cycle_counters *cc = &common->cc_ani;
174 int32_t listen_time;
176 listen_time = (cc->cycles - cc->rx_frame - cc->tx_frame) /
177 (common->clockrate * 1000);
179 memset(cc, 0, sizeof(*cc));
181 return listen_time;
183 EXPORT_SYMBOL(ath_hw_get_listen_time);