Re: [PATCH 06/10] carl9170: phy: populate per-channel TX power from EEPROM

[Christian Lamparter <chunkeey@gmail.com>]

On 3/12/26 11:38 AM, Masi Osmani wrote:
> Replace the hardcoded max_power = 18 dBm (marked XXX) in the
> channel definitions with actual per-channel values derived from
> the EEPROM calibration target power tables.
> 
> The new carl9170_get_max_tgt_power() function interpolates the
> maximum target power for a given frequency from the EEPROM's
> legacy OFDM and CCK target power tables, using the same frequency
> encoding and interpolation helpers already used by the power
> calibration code.  carl9170_update_channel_maxpower() iterates
> all registered channels and updates their max_power fields.


Why the need for interpolation here? Don't you just need to look
for the max(ctpl[idx].power, previous_value) within the band?

I'm not aware of any high-powered AR9170 devices. Were/are there any?

Cheers,
Christian

> 
> This is called during EEPROM parsing, so mac80211 and userspace
> see correct per-channel power limits from the start.  The CHAN
> macro default of 18 dBm remains as a safe fallback for channels
> where EEPROM data is missing.
> 
> Signed-off-by: Masi Osmani <mas-i@hotmail.de>
> ---
>   drivers/net/wireless/ath/carl9170/carl9170.h |  1 +
>   drivers/net/wireless/ath/carl9170/main.c     |  4 +-
>   drivers/net/wireless/ath/carl9170/phy.c      | 88 ++++++++++++++++++++
>   3 files changed, 92 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/net/wireless/ath/carl9170/carl9170.h b/drivers/net/wireless/ath/carl9170/carl9170.h
> index eaac859..a2ffa62 100644
> --- a/drivers/net/wireless/ath/carl9170/carl9170.h
> +++ b/drivers/net/wireless/ath/carl9170/carl9170.h
> @@ -602,6 +602,7 @@ int carl9170_led_set_state(struct ar9170 *ar, const u32 led_state);
>   int carl9170_set_channel(struct ar9170 *ar, struct ieee80211_channel *channel,
>   			 enum nl80211_channel_type bw);
>   int carl9170_get_noisefloor(struct ar9170 *ar);
> +void carl9170_update_channel_maxpower(struct ar9170 *ar);
>   
>   /* FW */
>   int carl9170_parse_firmware(struct ar9170 *ar);
> diff --git a/drivers/net/wireless/ath/carl9170/main.c b/drivers/net/wireless/ath/carl9170/main.c
> index d75688c..dcedcb1 100644
> --- a/drivers/net/wireless/ath/carl9170/main.c
> +++ b/drivers/net/wireless/ath/carl9170/main.c
> @@ -89,7 +89,7 @@ struct ieee80211_rate __carl9170_ratetable[] = {
>   #define CHAN(_freq, _idx) {		\
>   	.center_freq	= (_freq),	\
>   	.hw_value	= (_idx),	\
> -	.max_power	= 18, /* XXX */	\
> +	.max_power	= 18,		\
>   }
>   
>   static struct ieee80211_channel carl9170_2ghz_chantable[] = {
> @@ -1930,6 +1930,8 @@ static int carl9170_parse_eeprom(struct ar9170 *ar)
>   	if (!bands)
>   		return -EINVAL;
>   
> +	carl9170_update_channel_maxpower(ar);
> +
>   	ar->survey = devm_kcalloc(&ar->udev->dev, chans,
>   				  sizeof(struct survey_info), GFP_KERNEL);
>   	if (!ar->survey)
> diff --git a/drivers/net/wireless/ath/carl9170/phy.c b/drivers/net/wireless/ath/carl9170/phy.c
> index 34d9fd7..290c336 100644
> --- a/drivers/net/wireless/ath/carl9170/phy.c
> +++ b/drivers/net/wireless/ath/carl9170/phy.c
> @@ -1524,6 +1524,94 @@ static void carl9170_set_power_cal(struct ar9170 *ar, u32 freq,
>   	carl9170_calc_ctl(ar, freq, bw);
>   }
>   
> +static u8 carl9170_get_max_tgt_power(struct ar9170 *ar, u32 freq)
> +{
> +	struct ar9170_calibration_target_power_legacy *ctpl;
> +	int ntargets, idx, n, i;
> +	u8 f, max_power = 0;
> +	u8 pwr_freqs[AR5416_MAX_NUM_TGT_PWRS];
> +
> +	if (freq < 3000)
> +		f = freq - 2300;
> +	else
> +		f = (freq - 4800) / 5;
> +
> +	/* check legacy target powers (OFDM for 2G, 5G leg) */
> +	for (i = 0; i < 2; i++) {
> +		switch (i) {
> +		case 0:
> +			if (freq >= 3000) {
> +				ctpl = &ar->eeprom.cal_tgt_pwr_5G[0];
> +				ntargets = AR5416_NUM_5G_TARGET_PWRS;
> +			} else {
> +				ctpl = &ar->eeprom.cal_tgt_pwr_2G_ofdm[0];
> +				ntargets = AR5416_NUM_2G_OFDM_TARGET_PWRS;
> +			}
> +			break;
> +		case 1:
> +			if (freq < 3000) {
> +				ctpl = &ar->eeprom.cal_tgt_pwr_2G_cck[0];
> +				ntargets = AR5416_NUM_2G_CCK_TARGET_PWRS;
> +			} else {
> +				continue;
> +			}
> +			break;
> +		default:
> +			continue;
> +		}
> +
> +		for (n = 0; n < ntargets; n++) {
> +			if (ctpl[n].freq == 0xff)
> +				break;
> +			pwr_freqs[n] = ctpl[n].freq;
> +		}
> +		ntargets = n;
> +		if (ntargets < 2)
> +			continue;
> +
> +		idx = carl9170_find_freq_idx(ntargets, pwr_freqs, f);
> +		for (n = 0; n < 4; n++) {
> +			u8 pwr;
> +
> +			pwr = carl9170_interpolate_u8(f,
> +						     ctpl[idx + 0].freq,
> +						     ctpl[idx + 0].power[n],
> +						     ctpl[idx + 1].freq,
> +						     ctpl[idx + 1].power[n]);
> +			max_power = max(max_power, pwr);
> +		}
> +	}
> +
> +	/* target power is in half-dBm, max_power is in dBm */
> +	return max_power / 2;
> +}
> +
> +void carl9170_update_channel_maxpower(struct ar9170 *ar)
> +{
> +	struct ieee80211_supported_band *band;
> +	int i;
> +
> +	band = ar->hw->wiphy->bands[NL80211_BAND_2GHZ];
> +	if (band) {
> +		for (i = 0; i < band->n_channels; i++) {
> +			u8 pwr = carl9170_get_max_tgt_power(ar,
> +				band->channels[i].center_freq);
> +			if (pwr)
> +				band->channels[i].max_power = pwr;
> +		}
> +	}
> +
> +	band = ar->hw->wiphy->bands[NL80211_BAND_5GHZ];
> +	if (band) {
> +		for (i = 0; i < band->n_channels; i++) {
> +			u8 pwr = carl9170_get_max_tgt_power(ar,
> +				band->channels[i].center_freq);
> +			if (pwr)
> +				band->channels[i].max_power = pwr;
> +		}
> +	}
> +}
> +
>   int carl9170_get_noisefloor(struct ar9170 *ar)
>   {
>   	static const u32 phy_regs[] = {