Re: [PATCH for v4.4] iwlwifi: add workaround to disable wide channels in 5GHz

[Luciano Coelho <luciano.coelho@intel.com>]

On Tue, 2017-10-10 at 11:12 +0300, Luca Coelho wrote:
> From: Luca Coelho <luciano.coelho@intel.com>
> 
> commit 01a9c948a09348950515bf2abb6113ed83e696d8 upstream.
> 
> The OTP in some SKUs have erroneously allowed 40MHz and 80MHz channels
> in the 5.2GHz band.  The firmware has been modified to not allow this
> in those SKUs, so the driver needs to do the same otherwise the
> firmware will assert when we try to use it.
> 
> Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
> ---
>  drivers/net/wireless/iwlwifi/iwl-nvm-parse.c | 65 +++++++++++++++++++++++-----
>  1 file changed, 55 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/net/wireless/iwlwifi/iwl-nvm-parse.c b/drivers/net/wireless/iwlwifi/iwl-nvm-parse.c
> index d82984912e04..e7f58e00b5fb 100644
> --- a/drivers/net/wireless/iwlwifi/iwl-nvm-parse.c
> +++ b/drivers/net/wireless/iwlwifi/iwl-nvm-parse.c
> @@ -73,6 +73,7 @@
>  /* NVM offsets (in words) definitions */
>  enum wkp_nvm_offsets {
>  	/* NVM HW-Section offset (in words) definitions */
> +	SUBSYSTEM_ID = 0x0A,
>  	HW_ADDR = 0x15,
>  
>  	/* NVM SW-Section offset (in words) definitions */
> @@ -257,13 +258,12 @@ static u32 iwl_get_channel_flags(u8 ch_num, int ch_idx, bool is_5ghz,
>  static int iwl_init_channel_map(struct device *dev, const struct iwl_cfg *cfg,
>  				struct iwl_nvm_data *data,
>  				const __le16 * const nvm_ch_flags,
> -				bool lar_supported)
> +				bool lar_supported, bool no_wide_in_5ghz)
>  {
>  	int ch_idx;
>  	int n_channels = 0;
>  	struct ieee80211_channel *channel;
>  	u16 ch_flags;
> -	bool is_5ghz;
>  	int num_of_ch, num_2ghz_channels;
>  	const u8 *nvm_chan;
>  
> @@ -278,12 +278,20 @@ static int iwl_init_channel_map(struct device *dev, const struct iwl_cfg *cfg,
>  	}
>  
>  	for (ch_idx = 0; ch_idx < num_of_ch; ch_idx++) {
> +		bool is_5ghz = (ch_idx >= num_2ghz_channels);
> +
>  		ch_flags = __le16_to_cpup(nvm_ch_flags + ch_idx);
>  
> -		if (ch_idx >= num_2ghz_channels &&
> -		    !data->sku_cap_band_52GHz_enable)
> +		if (is_5ghz && !data->sku_cap_band_52GHz_enable)
>  			continue;
>  
> +		/* workaround to disable wide channels in 5GHz */
> +		if (no_wide_in_5ghz && is_5ghz) {
> +			ch_flags &= ~(NVM_CHANNEL_40MHZ |
> +				     NVM_CHANNEL_80MHZ |
> +				     NVM_CHANNEL_160MHZ);
> +		}
> +
>  		if (!lar_supported && !(ch_flags & NVM_CHANNEL_VALID)) {
>  			/*
>  			 * Channels might become valid later if lar is
> @@ -303,7 +311,7 @@ static int iwl_init_channel_map(struct device *dev, const struct iwl_cfg *cfg,
>  		n_channels++;
>  
>  		channel->hw_value = nvm_chan[ch_idx];
> -		channel->band = (ch_idx < num_2ghz_channels) ?
> +		channel->band = is_5ghz ?
>  				IEEE80211_BAND_2GHZ : IEEE80211_BAND_5GHZ;

Ooops, sorry, I made a mistake here.  I'll send v2.

--
Luca.