On Wed, Nov 24, 2010 at 10:31 AM, Jonathan Guerin <jonathan@xxxxxxxxxxxx> wrote:
> On Wed, Nov 24, 2010 at 5:09 AM, Nick Kossifidis <mickflemm@xxxxxxxxx> wrote:
>> * Extend get_default_sifs/slot_time to include timings for turbo
>> half and quarter rate modes.
>>
>> * AR5210 code for now uses timings already on core clock units
>> instead of usecs so rename them (we 'll clean it up later).
>>
>> Signed-off-by: Nick Kossifidis <mickflemm@xxxxxxxxx>
>> ---
>> drivers/net/wireless/ath/ath5k/ath5k.h | 24 ++++++++++++--
>> drivers/net/wireless/ath/ath5k/pcu.c | 52 ++++++++++++++++++++++++--------
>> drivers/net/wireless/ath/ath5k/qcu.c | 16 +++++----
>> 3 files changed, 68 insertions(+), 24 deletions(-)
>>
>> diff --git a/drivers/net/wireless/ath/ath5k/ath5k.h b/drivers/net/wireless/ath/ath5k/ath5k.h
>> index 005cad0..e11fc8f 100644
>> --- a/drivers/net/wireless/ath/ath5k/ath5k.h
>> +++ b/drivers/net/wireless/ath/ath5k/ath5k.h
>> @@ -226,16 +226,16 @@
>> #define AR5K_INIT_USEC 39
>> #define AR5K_INIT_USEC_TURBO 79
>> #define AR5K_INIT_USEC_32 31
>> -#define AR5K_INIT_SLOT_TIME 396
>> -#define AR5K_INIT_SLOT_TIME_TURBO 480
>> +#define AR5K_INIT_SLOT_TIME_CLOCK 396
>
> This comes out as 9.9us (with a clock multiplier of 40), rather than 9
> - should be 360?
>
>> +#define AR5K_INIT_SLOT_TIME_TURBO_CLOCK 480
>> #define AR5K_INIT_ACK_CTS_TIMEOUT 1024
>
> From a previous post I'd made:
>
> According to the 802.11-2007 spec document, the ACKTimeout value is
> (Section 9.2.8 ACK procedure):
> ACKTimeout = aSIFSTime + aSlotTime + aPHY-RX-START-Delay
>
> From Table 17-15—OFDM PHY characteristics, the values are:
> aSIFSTime = 16
> aSlotTime = 9
> aPHY-RX-START-Delay = 25
>
> Therefore, ACKTimeout = 50
>
> With a value of 1024, the ACKTIMEOUT is actually 25.
>
>> #define AR5K_INIT_ACK_CTS_TIMEOUT_TURBO 0x08000800
>> #define AR5K_INIT_PROG_IFS 920
>> #define AR5K_INIT_PROG_IFS_TURBO 960
>> #define AR5K_INIT_EIFS 3440
>
> From the 802.11-2007 Spec (9.2.10 DCF timing relations):
> The EIFS is derived from the SIFS and the DIFS and the length of time
> it takes to transmit an ACK Control frame at the lowest PHY mandatory
> rate by the following equation:
> EIFS = aSIFSTime + DIFS + ACKTxTime
> where ACKTxTime is the time expressed in microseconds required to
> transmit an ACK frame, including
> preamble, PLCP header and any additional PHY dependent information, at
> the lowest PHY mandatory rate.
>
> So, EIFS = 16 + 32 + 44 (ACKTX @ 24Mbps) = 92
> or 16 + 32 + 60 (ACKTX @ 6Mbps) = 108
>
> The current value is 86, which I guess is a nice midpoint, but is
> there any reasoning for this value? It should really be set to the
> longest value of 108, as an EIFS is only used when we have no
> information about a frame because it failed the checksum.
>
>> #define AR5K_INIT_EIFS_TURBO 6880
>> -#define AR5K_INIT_SIFS 560
>> -#define AR5K_INIT_SIFS_TURBO 480
>> +#define AR5K_INIT_SIFS_CLOCK 560
>
> This is wrong, when you divide by the clock rate, you get a SIFS of 14, not 16.
>
> Cheers,
>
> Jonathan
Just as an aside, I didn't mean to hijack Nick's patches for this, but
these are some things that I've been discussing with Bruno. I'm happy
to provide a separate patch to remedy these if required.
Cheers,
Jonathan
>
>> +#define AR5K_INIT_SIFS_TURBO_CLOCK 480
>> #define AR5K_INIT_SH_RETRY 10
>> #define AR5K_INIT_LG_RETRY AR5K_INIT_SH_RETRY
>> #define AR5K_INIT_SSH_RETRY 32
>> @@ -251,6 +251,22 @@
>> (AR5K_INIT_PROG_IFS_TURBO) \
>> )
>>
>> +/* Slot time */
>> +#define AR5K_INIT_SLOT_TIME_TURBO 6
>> +#define AR5K_INIT_SLOT_TIME_DEFAULT 9
>> +#define AR5K_INIT_SLOT_TIME_HALF_RATE 13
>> +#define AR5K_INIT_SLOT_TIME_QUARTER_RATE 21
>> +#define AR5K_INIT_SLOT_TIME_B 20
>> +#define AR5K_SLOT_TIME_MAX 0xffff
>> +
>> +/* SIFS */
>> +#define AR5K_INIT_SIFS_TURBO 6
>> +/* XXX: 8 from initvals 10 from standard */
>> +#define AR5K_INIT_SIFS_DEFAULT_BG 8
>> +#define AR5K_INIT_SIFS_DEFAULT_A 16
>> +#define AR5K_INIT_SIFS_HALF_RATE 32
>> +#define AR5K_INIT_SIFS_QUARTER_RATE 64
>> +
>> /* Rx latency for 5 and 10MHz operation (max ?) */
>> #define AR5K_INIT_RX_LAT_MAX 63
>> /* Tx latencies from initvals (5212 only but no problem
>> diff --git a/drivers/net/wireless/ath/ath5k/pcu.c b/drivers/net/wireless/ath/ath5k/pcu.c
>> index ae99e37..cb6e277 100644
>> --- a/drivers/net/wireless/ath/ath5k/pcu.c
>> +++ b/drivers/net/wireless/ath/ath5k/pcu.c
>> @@ -43,14 +43,27 @@
>> static unsigned int ath5k_hw_get_default_slottime(struct ath5k_hw *ah)
>> {
>> struct ieee80211_channel *channel = ah->ah_current_channel;
>> + unsigned int slot_time;
>>
>> - if (channel->hw_value & CHANNEL_TURBO)
>> - return 6; /* both turbo modes */
>> + switch (ah->ah_bwmode) {
>> + case AR5K_BWMODE_40MHZ:
>> + slot_time = AR5K_INIT_SLOT_TIME_TURBO;
>> + break;
>> + case AR5K_BWMODE_10MHZ:
>> + slot_time = AR5K_INIT_SLOT_TIME_HALF_RATE;
>> + break;
>> + case AR5K_BWMODE_5MHZ:
>> + slot_time = AR5K_INIT_SLOT_TIME_QUARTER_RATE;
>> + break;
>> + case AR5K_BWMODE_DEFAULT:
>> + slot_time = AR5K_INIT_SLOT_TIME_DEFAULT;
>> + default:
>> + if (channel->hw_value & CHANNEL_CCK)
>> + slot_time = AR5K_INIT_SLOT_TIME_B;
>> + break;
>> + }
>>
>> - if (channel->hw_value & CHANNEL_CCK)
>> - return 20; /* 802.11b */
>> -
>> - return 9; /* 802.11 a/g */
>> + return slot_time;
>> }
>>
>> /**
>> @@ -58,17 +71,30 @@ static unsigned int ath5k_hw_get_default_slottime(struct ath5k_hw *ah)
>> *
>> * @ah: The &struct ath5k_hw
>> */
>> -static unsigned int ath5k_hw_get_default_sifs(struct ath5k_hw *ah)
>> +unsigned int ath5k_hw_get_default_sifs(struct ath5k_hw *ah)
>> {
>> struct ieee80211_channel *channel = ah->ah_current_channel;
>> + unsigned int sifs;
>>
>> - if (channel->hw_value & CHANNEL_TURBO)
>> - return 8; /* both turbo modes */
>> + switch (ah->ah_bwmode) {
>> + case AR5K_BWMODE_40MHZ:
>> + sifs = AR5K_INIT_SIFS_TURBO;
>> + break;
>> + case AR5K_BWMODE_10MHZ:
>> + sifs = AR5K_INIT_SIFS_HALF_RATE;
>> + break;
>> + case AR5K_BWMODE_5MHZ:
>> + sifs = AR5K_INIT_SIFS_QUARTER_RATE;
>> + break;
>> + case AR5K_BWMODE_DEFAULT:
>> + sifs = AR5K_INIT_SIFS_DEFAULT_BG;
>> + default:
>> + if (channel->hw_value & CHANNEL_5GHZ)
>> + sifs = AR5K_INIT_SIFS_DEFAULT_A;
>> + break;
>> + }
>>
>> - if (channel->hw_value & CHANNEL_5GHZ)
>> - return 16; /* 802.11a */
>> -
>> - return 10; /* 802.11 b/g */
>> + return sifs;
>> }
>>
>> /**
>> diff --git a/drivers/net/wireless/ath/ath5k/qcu.c b/drivers/net/wireless/ath/ath5k/qcu.c
>> index c422d5c..6eb6838 100644
>> --- a/drivers/net/wireless/ath/ath5k/qcu.c
>> +++ b/drivers/net/wireless/ath/ath5k/qcu.c
>> @@ -297,7 +297,8 @@ int ath5k_hw_reset_tx_queue(struct ath5k_hw *ah, unsigned int queue)
>>
>> /* Set Slot time */
>> ath5k_hw_reg_write(ah, (ah->ah_bwmode == AR5K_BWMODE_40MHZ) ?
>> - AR5K_INIT_SLOT_TIME_TURBO : AR5K_INIT_SLOT_TIME,
>> + AR5K_INIT_SLOT_TIME_TURBO_CLOCK :
>> + AR5K_INIT_SLOT_TIME_CLOCK,
>> AR5K_SLOT_TIME);
>> /* Set ACK_CTS timeout */
>> ath5k_hw_reg_write(ah, (ah->ah_bwmode == AR5K_BWMODE_40MHZ) ?
>> @@ -306,15 +307,16 @@ int ath5k_hw_reset_tx_queue(struct ath5k_hw *ah, unsigned int queue)
>>
>> /* Set IFS0 */
>> if (ah->ah_bwmode == AR5K_BWMODE_40MHZ) {
>> - ath5k_hw_reg_write(ah, ((AR5K_INIT_SIFS_TURBO +
>> - tq->tqi_aifs * AR5K_INIT_SLOT_TIME_TURBO) <<
>> - AR5K_IFS0_DIFS_S) | AR5K_INIT_SIFS_TURBO,
>> + ath5k_hw_reg_write(ah, ((AR5K_INIT_SIFS_TURBO_CLOCK +
>> + tq->tqi_aifs * AR5K_INIT_SLOT_TIME_TURBO_CLOCK)
>> + << AR5K_IFS0_DIFS_S) |
>> + AR5K_INIT_SIFS_TURBO_CLOCK,
>> AR5K_IFS0);
>> } else {
>> - ath5k_hw_reg_write(ah, ((AR5K_INIT_SIFS +
>> - tq->tqi_aifs * AR5K_INIT_SLOT_TIME) <<
>> + ath5k_hw_reg_write(ah, ((AR5K_INIT_SIFS_CLOCK +
>> + tq->tqi_aifs * AR5K_INIT_SLOT_TIME_CLOCK) <<
>> AR5K_IFS0_DIFS_S) |
>> - AR5K_INIT_SIFS, AR5K_IFS0);
>> + AR5K_INIT_SIFS_CLOCK, AR5K_IFS0);
>> }
>>
>> /* Set IFS1 */
>> _______________________________________________
>> ath5k-devel mailing list
>> ath5k-devel@xxxxxxxxxxxxxxx
>> https://lists.ath5k.org/mailman/listinfo/ath5k-devel
>>
>
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