Message-ID: <4BD76360.2070005@free.fr>
Date: Wed, 28 Apr 2010 00:21:20 +0200
From: Benoit PAPILLAULT <benoit.papillault@free.fr>
MIME-Version: 1.0
To: Christian Lamparter <chunkeey@googlemail.com>
CC: linux-wireless@vger.kernel.org
Subject: Re: [RFT] ar9170: implement get_survey
References: <201004272323.22107.chunkeey@googlemail.com>
In-Reply-To: <201004272323.22107.chunkeey@googlemail.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Sender: linux-wireless-owner@vger.kernel.org

Christian Lamparter a ?crit :
> This patch adds a basic get_survey for ar9170.
>
> Survey data from wlan1
> 	frequency:	2412 MHz
> 	noise:		-85 dBm
>
> TODO:
>   Currently, the noise level is updated only by a channel change.
>   Now, we could simply add another ar9170_set_channel to always get
>   a fresh result, but then we risk a RF lockup.
>   
It seems to be a good start. The code is very similar to what is used in 
ath9k. Just few questions below.

> ---
> diff --git a/drivers/net/wireless/ath/ar9170/ar9170.h b/drivers/net/wireless/ath/ar9170/ar9170.h
> index dc662b7..26fa31e 100644
> --- a/drivers/net/wireless/ath/ar9170/ar9170.h
> +++ b/drivers/net/wireless/ath/ar9170/ar9170.h
> @@ -198,7 +198,7 @@ struct ar9170 {
>  
>  	/* PHY */
>  	struct ieee80211_channel *channel;
> -	int noise[4];
> +	int noise[6];
>  
>  	/* power calibration data */
>  	u8 power_5G_leg[4];
> @@ -302,5 +302,5 @@ int ar9170_init_phy(struct ar9170 *ar, enum ieee80211_band band);
>  int ar9170_init_rf(struct ar9170 *ar);
>  int ar9170_set_channel(struct ar9170 *ar, struct ieee80211_channel *channel,
>  		       enum ar9170_rf_init_mode rfi, enum ar9170_bw bw);
> -
> +int ar9170_get_noisefloor(struct ar9170 *ar);
>  #endif /* __AR9170_H */
> diff --git a/drivers/net/wireless/ath/ar9170/main.c b/drivers/net/wireless/ath/ar9170/main.c
> index 3247db8..1e422ed 100644
> --- a/drivers/net/wireless/ath/ar9170/main.c
> +++ b/drivers/net/wireless/ath/ar9170/main.c
> @@ -2485,6 +2485,25 @@ static int ar9170_ampdu_action(struct ieee80211_hw *hw,
>  	return 0;
>  }
>  
> +static int ar9170_op_get_survey(struct ieee80211_hw *hw, int idx,
> +				struct survey_info *survey)
> +{
> +	struct ar9170 *ar = hw->priv;
> +	int err;
> +
> +	if (idx != 0)
> +		return -ENOENT;
> +
> +	err = ar9170_get_noisefloor(ar);
> +	if (err)
> +		return err;
> +
> +	survey->channel = ar->channel;
> +	survey->filled = SURVEY_INFO_NOISE_DBM;
> +	survey->noise = ar->noise[0];
> +	return 0;
> +}
> +
>  static const struct ieee80211_ops ar9170_ops = {
>  	.start			= ar9170_op_start,
>  	.stop			= ar9170_op_stop,
> @@ -2501,6 +2520,7 @@ static const struct ieee80211_ops ar9170_ops = {
>  	.sta_add		= ar9170_sta_add,
>  	.sta_remove		= ar9170_sta_remove,
>  	.get_stats		= ar9170_get_stats,
> +	.get_survey		= ar9170_op_get_survey,
>  	.ampdu_action		= ar9170_ampdu_action,
>  };
>  
> diff --git a/drivers/net/wireless/ath/ar9170/phy.c b/drivers/net/wireless/ath/ar9170/phy.c
> index 45a415e..31ff163 100644
> --- a/drivers/net/wireless/ath/ar9170/phy.c
> +++ b/drivers/net/wireless/ath/ar9170/phy.c
> @@ -1584,6 +1584,31 @@ static int ar9170_calc_noise_dbm(u32 raw_noise)
>  		return (raw_noise & 0xff) >> 1;
>  }
>  
> +int ar9170_get_noisefloor(struct ar9170 *ar)
> +{
> +	static const u32 phy_regs[] = {
> +		0x1c5864, 0x1c6864, 0x1c7864,
> +		0x1c59bc, 0x1c69bc, 0x1c79bc };
>   
Maybe #define would be more appropriate. Moreover, it's clear in my 
notes that some ar9170 registers are just ath9k registers + 0x1bc000.
> +	u32 phy_res[ARRAY_SIZE(phy_regs)];
> +	int err, i;
> +
> +	BUILD_BUG_ON(ARRAY_SIZE(phy_regs) != ARRAY_SIZE(ar->noise));
> +
> +	err = ar9170_read_mreg(ar, ARRAY_SIZE(phy_regs), phy_regs, phy_res);
> +	if (err)
> +		return err;
> +
> +	for (i = 0; i < ARRAY_SIZE(phy_regs); i++) {
> +		ar->noise[i] = ar9170_calc_noise_dbm(
> +			(phy_res[i] >> 19) & 0x1ff);
> +
> +		ar->noise[i + 3] = ar9170_calc_noise_dbm(
> +			(phy_res[i + 3] >> 23) & 0x1ff);
> +	}
> +
> +	return 0;
> +}
> +
>  int ar9170_set_channel(struct ar9170 *ar, struct ieee80211_channel *channel,
>  		       enum ar9170_rf_init_mode rfi, enum ar9170_bw bw)
>  {
> @@ -1708,12 +1733,12 @@ int ar9170_set_channel(struct ar9170 *ar, struct ieee80211_channel *channel,
>  		}
>  	}
>  
> -	for (i = 0; i < 2; i++) {
> +	for (i = 0; i < 3; i++) {
>   
Why using 3 RX channels ? ar9170 is always 2x2, isn't it ? And why read 
3 values since only one will be used in ar9170_op_get_survey?

Maybe we should combine the 3 values before reporting a single value ?
>  		ar->noise[i] = ar9170_calc_noise_dbm(
> -				(le32_to_cpu(vals[2 + i]) >> 19) & 0x1ff);
> +				(le32_to_cpu(vals[i + 1]) >> 19) & 0x1ff);
>  
> -		ar->noise[i + 2] = ar9170_calc_noise_dbm(
> -				    (le32_to_cpu(vals[5 + i]) >> 23) & 0x1ff);
> +		ar->noise[i + 3] = ar9170_calc_noise_dbm(
> +				    (le32_to_cpu(vals[i + 4]) >> 23) & 0x1ff);
>  	}
>  
>  	ar->channel = channel;
>   
Moreover (but my patch for ath9k has the very same error), I think we 
are reported the noise floor calibration result which is not the noise 
at all... that might be another story anyway.

Regards,
Benoit