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- /*
- * Copyright (c) 2009 Atheros Communications Inc.
- *
- * Permission to use, copy, modify, and/or distribute this software for any
- * purpose with or without fee is hereby granted, provided that the above
- * copyright notice and this permission notice appear in all copies.
- *
- * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
- * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
- * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
- * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
- * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
- * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
- * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
- */
- #include <linux/export.h>
- #include <asm/unaligned.h>
- #include "ath.h"
- #include "reg.h"
- #define REG_READ (common->ops->read)
- #define REG_WRITE(_ah, _reg, _val) (common->ops->write)(_ah, _val, _reg)
- /**
- * ath_hw_set_bssid_mask - filter out bssids we listen
- *
- * @common: the ath_common struct for the device.
- *
- * BSSID masking is a method used by AR5212 and newer hardware to inform PCU
- * which bits of the interface's MAC address should be looked at when trying
- * to decide which packets to ACK. In station mode and AP mode with a single
- * BSS every bit matters since we lock to only one BSS. In AP mode with
- * multiple BSSes (virtual interfaces) not every bit matters because hw must
- * accept frames for all BSSes and so we tweak some bits of our mac address
- * in order to have multiple BSSes.
- *
- * NOTE: This is a simple filter and does *not* filter out all
- * relevant frames. Some frames that are not for us might get ACKed from us
- * by PCU because they just match the mask.
- *
- * When handling multiple BSSes you can get the BSSID mask by computing the
- * set of ~ ( MAC XOR BSSID ) for all bssids we handle.
- *
- * When you do this you are essentially computing the common bits of all your
- * BSSes. Later it is assumed the hardware will "and" (&) the BSSID mask with
- * the MAC address to obtain the relevant bits and compare the result with
- * (frame's BSSID & mask) to see if they match.
- *
- * Simple example: on your card you have have two BSSes you have created with
- * BSSID-01 and BSSID-02. Lets assume BSSID-01 will not use the MAC address.
- * There is another BSSID-03 but you are not part of it. For simplicity's sake,
- * assuming only 4 bits for a mac address and for BSSIDs you can then have:
- *
- * \
- * MAC: 0001 |
- * BSSID-01: 0100 | --> Belongs to us
- * BSSID-02: 1001 |
- * /
- * -------------------
- * BSSID-03: 0110 | --> External
- * -------------------
- *
- * Our bssid_mask would then be:
- *
- * On loop iteration for BSSID-01:
- * ~(0001 ^ 0100) -> ~(0101)
- * -> 1010
- * bssid_mask = 1010
- *
- * On loop iteration for BSSID-02:
- * bssid_mask &= ~(0001 ^ 1001)
- * bssid_mask = (1010) & ~(0001 ^ 1001)
- * bssid_mask = (1010) & ~(1000)
- * bssid_mask = (1010) & (0111)
- * bssid_mask = 0010
- *
- * A bssid_mask of 0010 means "only pay attention to the second least
- * significant bit". This is because its the only bit common
- * amongst the MAC and all BSSIDs we support. To findout what the real
- * common bit is we can simply "&" the bssid_mask now with any BSSID we have
- * or our MAC address (we assume the hardware uses the MAC address).
- *
- * Now, suppose there's an incoming frame for BSSID-03:
- *
- * IFRAME-01: 0110
- *
- * An easy eye-inspeciton of this already should tell you that this frame
- * will not pass our check. This is because the bssid_mask tells the
- * hardware to only look at the second least significant bit and the
- * common bit amongst the MAC and BSSIDs is 0, this frame has the 2nd LSB
- * as 1, which does not match 0.
- *
- * So with IFRAME-01 we *assume* the hardware will do:
- *
- * allow = (IFRAME-01 & bssid_mask) == (bssid_mask & MAC) ? 1 : 0;
- * --> allow = (0110 & 0010) == (0010 & 0001) ? 1 : 0;
- * --> allow = (0010) == 0000 ? 1 : 0;
- * --> allow = 0
- *
- * Lets now test a frame that should work:
- *
- * IFRAME-02: 0001 (we should allow)
- *
- * allow = (IFRAME-02 & bssid_mask) == (bssid_mask & MAC) ? 1 : 0;
- * --> allow = (0001 & 0010) == (0010 & 0001) ? 1 :0;
- * --> allow = (0000) == (0000)
- * --> allow = 1
- *
- * Other examples:
- *
- * IFRAME-03: 0100 --> allowed
- * IFRAME-04: 1001 --> allowed
- * IFRAME-05: 1101 --> allowed but its not for us!!!
- *
- */
- void ath_hw_setbssidmask(struct ath_common *common)
- {
- void *ah = common->ah;
- u32 id1;
- REG_WRITE(ah, AR_STA_ID0, get_unaligned_le32(common->macaddr));
- id1 = REG_READ(ah, AR_STA_ID1) & ~AR_STA_ID1_SADH_MASK;
- id1 |= get_unaligned_le16(common->macaddr + 4);
- REG_WRITE(ah, AR_STA_ID1, id1);
- REG_WRITE(ah, AR_BSSMSKL, get_unaligned_le32(common->bssidmask));
- REG_WRITE(ah, AR_BSSMSKU, get_unaligned_le16(common->bssidmask + 4));
- }
- EXPORT_SYMBOL(ath_hw_setbssidmask);
- /**
- * ath_hw_cycle_counters_update - common function to update cycle counters
- *
- * @common: the ath_common struct for the device.
- *
- * This function is used to update all cycle counters in one place.
- * It has to be called while holding common->cc_lock!
- */
- void ath_hw_cycle_counters_update(struct ath_common *common)
- {
- u32 cycles, busy, rx, tx;
- void *ah = common->ah;
- /* freeze */
- REG_WRITE(ah, AR_MIBC, AR_MIBC_FMC);
- /* read */
- cycles = REG_READ(ah, AR_CCCNT);
- busy = REG_READ(ah, AR_RCCNT);
- rx = REG_READ(ah, AR_RFCNT);
- tx = REG_READ(ah, AR_TFCNT);
- /* clear */
- REG_WRITE(ah, AR_CCCNT, 0);
- REG_WRITE(ah, AR_RFCNT, 0);
- REG_WRITE(ah, AR_RCCNT, 0);
- REG_WRITE(ah, AR_TFCNT, 0);
- /* unfreeze */
- REG_WRITE(ah, AR_MIBC, 0);
- /* update all cycle counters here */
- common->cc_ani.cycles += cycles;
- common->cc_ani.rx_busy += busy;
- common->cc_ani.rx_frame += rx;
- common->cc_ani.tx_frame += tx;
- common->cc_survey.cycles += cycles;
- common->cc_survey.rx_busy += busy;
- common->cc_survey.rx_frame += rx;
- common->cc_survey.tx_frame += tx;
- }
- EXPORT_SYMBOL(ath_hw_cycle_counters_update);
- int32_t ath_hw_get_listen_time(struct ath_common *common)
- {
- struct ath_cycle_counters *cc = &common->cc_ani;
- int32_t listen_time;
- listen_time = (cc->cycles - cc->rx_frame - cc->tx_frame) /
- (common->clockrate * 1000);
- memset(cc, 0, sizeof(*cc));
- return listen_time;
- }
- EXPORT_SYMBOL(ath_hw_get_listen_time);
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