hw.c (6540B)
1/* 2 * Copyright (c) 2009 Atheros Communications Inc. 3 * 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. 7 * 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. 15 */ 16 17#include <linux/export.h> 18#include <asm/unaligned.h> 19 20#include "ath.h" 21#include "reg.h" 22 23#define REG_READ (common->ops->read) 24#define REG_WRITE(_ah, _reg, _val) (common->ops->write)(_ah, _val, _reg) 25 26/** 27 * ath_hw_setbssidmask - filter out bssids we listen 28 * 29 * @common: the ath_common struct for the device. 30 * 31 * BSSID masking is a method used by AR5212 and newer hardware to inform PCU 32 * which bits of the interface's MAC address should be looked at when trying 33 * to decide which packets to ACK. In station mode and AP mode with a single 34 * BSS every bit matters since we lock to only one BSS. In AP mode with 35 * multiple BSSes (virtual interfaces) not every bit matters because hw must 36 * accept frames for all BSSes and so we tweak some bits of our mac address 37 * in order to have multiple BSSes. 38 * 39 * NOTE: This is a simple filter and does *not* filter out all 40 * relevant frames. Some frames that are not for us might get ACKed from us 41 * by PCU because they just match the mask. 42 * 43 * When handling multiple BSSes you can get the BSSID mask by computing the 44 * set of ~ ( MAC XOR BSSID ) for all bssids we handle. 45 * 46 * When you do this you are essentially computing the common bits of all your 47 * BSSes. Later it is assumed the hardware will "and" (&) the BSSID mask with 48 * the MAC address to obtain the relevant bits and compare the result with 49 * (frame's BSSID & mask) to see if they match. 50 * 51 * Simple example: on your card you have have two BSSes you have created with 52 * BSSID-01 and BSSID-02. Lets assume BSSID-01 will not use the MAC address. 53 * There is another BSSID-03 but you are not part of it. For simplicity's sake, 54 * assuming only 4 bits for a mac address and for BSSIDs you can then have: 55 * 56 * \ 57 * MAC: 0001 | 58 * BSSID-01: 0100 | --> Belongs to us 59 * BSSID-02: 1001 | 60 * / 61 * ------------------- 62 * BSSID-03: 0110 | --> External 63 * ------------------- 64 * 65 * Our bssid_mask would then be: 66 * 67 * On loop iteration for BSSID-01: 68 * ~(0001 ^ 0100) -> ~(0101) 69 * -> 1010 70 * bssid_mask = 1010 71 * 72 * On loop iteration for BSSID-02: 73 * bssid_mask &= ~(0001 ^ 1001) 74 * bssid_mask = (1010) & ~(0001 ^ 1001) 75 * bssid_mask = (1010) & ~(1000) 76 * bssid_mask = (1010) & (0111) 77 * bssid_mask = 0010 78 * 79 * A bssid_mask of 0010 means "only pay attention to the second least 80 * significant bit". This is because its the only bit common 81 * amongst the MAC and all BSSIDs we support. To findout what the real 82 * common bit is we can simply "&" the bssid_mask now with any BSSID we have 83 * or our MAC address (we assume the hardware uses the MAC address). 84 * 85 * Now, suppose there's an incoming frame for BSSID-03: 86 * 87 * IFRAME-01: 0110 88 * 89 * An easy eye-inspeciton of this already should tell you that this frame 90 * will not pass our check. This is because the bssid_mask tells the 91 * hardware to only look at the second least significant bit and the 92 * common bit amongst the MAC and BSSIDs is 0, this frame has the 2nd LSB 93 * as 1, which does not match 0. 94 * 95 * So with IFRAME-01 we *assume* the hardware will do: 96 * 97 * allow = (IFRAME-01 & bssid_mask) == (bssid_mask & MAC) ? 1 : 0; 98 * --> allow = (0110 & 0010) == (0010 & 0001) ? 1 : 0; 99 * --> allow = (0010) == 0000 ? 1 : 0; 100 * --> allow = 0 101 * 102 * Lets now test a frame that should work: 103 * 104 * IFRAME-02: 0001 (we should allow) 105 * 106 * allow = (IFRAME-02 & bssid_mask) == (bssid_mask & MAC) ? 1 : 0; 107 * --> allow = (0001 & 0010) == (0010 & 0001) ? 1 :0; 108 * --> allow = (0000) == (0000) 109 * --> allow = 1 110 * 111 * Other examples: 112 * 113 * IFRAME-03: 0100 --> allowed 114 * IFRAME-04: 1001 --> allowed 115 * IFRAME-05: 1101 --> allowed but its not for us!!! 116 * 117 */ 118void ath_hw_setbssidmask(struct ath_common *common) 119{ 120 void *ah = common->ah; 121 u32 id1; 122 123 REG_WRITE(ah, AR_STA_ID0, get_unaligned_le32(common->macaddr)); 124 id1 = REG_READ(ah, AR_STA_ID1) & ~AR_STA_ID1_SADH_MASK; 125 id1 |= get_unaligned_le16(common->macaddr + 4); 126 REG_WRITE(ah, AR_STA_ID1, id1); 127 128 REG_WRITE(ah, AR_BSSMSKL, get_unaligned_le32(common->bssidmask)); 129 REG_WRITE(ah, AR_BSSMSKU, get_unaligned_le16(common->bssidmask + 4)); 130} 131EXPORT_SYMBOL(ath_hw_setbssidmask); 132 133 134/** 135 * ath_hw_cycle_counters_update - common function to update cycle counters 136 * 137 * @common: the ath_common struct for the device. 138 * 139 * This function is used to update all cycle counters in one place. 140 * It has to be called while holding common->cc_lock! 141 */ 142void ath_hw_cycle_counters_update(struct ath_common *common) 143{ 144 u32 cycles, busy, rx, tx; 145 void *ah = common->ah; 146 147 /* freeze */ 148 REG_WRITE(ah, AR_MIBC, AR_MIBC_FMC); 149 150 /* read */ 151 cycles = REG_READ(ah, AR_CCCNT); 152 busy = REG_READ(ah, AR_RCCNT); 153 rx = REG_READ(ah, AR_RFCNT); 154 tx = REG_READ(ah, AR_TFCNT); 155 156 /* clear */ 157 REG_WRITE(ah, AR_CCCNT, 0); 158 REG_WRITE(ah, AR_RFCNT, 0); 159 REG_WRITE(ah, AR_RCCNT, 0); 160 REG_WRITE(ah, AR_TFCNT, 0); 161 162 /* unfreeze */ 163 REG_WRITE(ah, AR_MIBC, 0); 164 165 /* update all cycle counters here */ 166 common->cc_ani.cycles += cycles; 167 common->cc_ani.rx_busy += busy; 168 common->cc_ani.rx_frame += rx; 169 common->cc_ani.tx_frame += tx; 170 171 common->cc_survey.cycles += cycles; 172 common->cc_survey.rx_busy += busy; 173 common->cc_survey.rx_frame += rx; 174 common->cc_survey.tx_frame += tx; 175} 176EXPORT_SYMBOL(ath_hw_cycle_counters_update); 177 178int32_t ath_hw_get_listen_time(struct ath_common *common) 179{ 180 struct ath_cycle_counters *cc = &common->cc_ani; 181 int32_t listen_time; 182 183 listen_time = (cc->cycles - cc->rx_frame - cc->tx_frame) / 184 (common->clockrate * 1000); 185 186 memset(cc, 0, sizeof(*cc)); 187 188 return listen_time; 189} 190EXPORT_SYMBOL(ath_hw_get_listen_time);