Re: [PATCH 5/7] ath9k_hw: fix PA predistortion training power selection

[Felix Fietkau <nbd@openwrt.org>]

On 2010-12-13 7:02 AM, Vasanthakumar Thiagarajan wrote:
> On Sun, Dec 12, 2010 at 07:04:35PM +0530, Felix Fietkau wrote:
>> The EEPROM contains scale factors for the tx power, which define
>> the range of allowable difference between target power and training
>> power. If the difference is too big, PA predistortion cannot be used.
>> For 2.4 GHz there is only one scale factor, for 5 GHz there are
>> three, depending on the specific frequency range.
>> 
>> Signed-off-by: Felix Fietkau <nbd@openwrt.org>
>> ---
>>  drivers/net/wireless/ath/ath9k/ar9003_eeprom.c |    8 ++
>>  drivers/net/wireless/ath/ath9k/ar9003_paprd.c  |   99 ++++++++++++++++++++----
>>  drivers/net/wireless/ath/ath9k/ar9003_phy.h    |    8 ++
>>  drivers/net/wireless/ath/ath9k/hw.h            |    2 +
>>  drivers/net/wireless/ath/ath9k/main.c          |    4 +-
>>  5 files changed, 104 insertions(+), 17 deletions(-)
>> 
>> diff --git a/drivers/net/wireless/ath/ath9k/ar9003_eeprom.c b/drivers/net/wireless/ath/ath9k/ar9003_eeprom.c
>> index 5ad37d0..ff03b42 100644
>> --- a/drivers/net/wireless/ath/ath9k/ar9003_eeprom.c
>> +++ b/drivers/net/wireless/ath/ath9k/ar9003_eeprom.c
>> @@ -4798,6 +4798,14 @@ static void ath9k_hw_ar9300_set_txpower(struct ath_hw *ah,
>>  	/* Write target power array to registers */
>>  	ar9003_hw_tx_power_regwrite(ah, targetPowerValT2);
>>  	ar9003_hw_calibration_apply(ah, chan->channel);
>> +
>> +	if (IS_CHAN_2GHZ(chan))
>> +		i = ALL_TARGET_HT20_0_8_16;
>> +	else if (IS_CHAN_HT40(chan))
>> +		i = ALL_TARGET_HT40_7;
> 
> It looks like ALL_TARGET_HT40_0_8_16 being used in 11NGHT40.
You're right, I'll resend.

>> +	else
>> +		i = ALL_TARGET_HT20_7;
>> +	ah->paprd_target_power = targetPowerValT2[i];
>>  }
>>  
>>  static u16 ath9k_hw_ar9300_get_spur_channel(struct ath_hw *ah,
>> diff --git a/drivers/net/wireless/ath/ath9k/ar9003_paprd.c b/drivers/net/wireless/ath/ath9k/ar9003_paprd.c
>> +static int get_streams(int mask)
>> +{
>> +	return !!(mask & BIT(0)) + !!(mask & BIT(1)) + !!(mask & BIT(2));
>> +}
> ah->caps.max_txchains can be used instead of this function.
No, it cannot. I need the number of active chains, not the number of
chains that the hardware is capable of using.

>> +
>> +static int ar9003_get_training_power_5g(struct ath_hw *ah)
>> +{
>> +	struct ath_common *common = ath9k_hw_common(ah);
>> +	struct ar9300_eeprom *eep = &ah->eeprom.ar9300_eep;
>> +	struct ar9300_modal_eep_header *hdr = &eep->modalHeader5G;
>> +	struct ath9k_channel *chan = ah->curchan;
>> +	unsigned int power, scale, delta;
>> +
>> +	if (chan->channel >= 5700)
>> +		scale = MS(hdr->papdRateMaskHt20, AR9300_PAPRD_SCALE_1);
>> +	else if (chan->channel >= 5400)
>> +		scale = MS(hdr->papdRateMaskHt40, AR9300_PAPRD_SCALE_2);
>> +	else
>> +		scale = MS(hdr->papdRateMaskHt40, AR9300_PAPRD_SCALE_1);
> 
> A helper function would be nice to get the paprd scale factor which
> will also be used to disable paprd for particular rates. Anyway, i'm
> doing changes to disable paprd based on scale factor and tx power,
> i'll add a helper in my series.
OK.

- Felix