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

[Vasanthakumar Thiagarajan <vasanth@atheros.com>]

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.
> +	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.

> +
> +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.
 
Vasanth