Re: [PATCH 2/5] cfg80211: allow drivers to provide regulatory settings

[Arend van Spriel <arend@broadcom.com>]

On 11-06-14 08:55, Arik Nemtsov wrote:
> Define a new wiphy callback allowing drivers to provide regulatory
> settings.
>
> Only The first wiphy registered with this callback will be able to provide
> regulatory domain info. If such a wiphy exists, it takes precedence over
> other data sources.

I should probably dig through linux-wireless archive for background 
info, but how is this different from the wiphy_apply_custom_regulatory() 
call. Is this for devices that have a regulatory database of sorts in 
the device firmware?

Regards,
Arend

> Change-Id: If8f8faf1d127120ae464b45098c5edbc5aee3dc0
> Signed-off-by: Arik Nemtsov <arikx.nemtsov@intel.com>
> Reviewed-on: https://gerrit.rds.intel.com/32858
> Tested-by: IWL Jenkins
> Reviewed-by: Johannes Berg <johannes.berg@intel.com>
> ---
>   include/net/cfg80211.h | 16 +++++++++++++
>   net/wireless/reg.c     | 65 +++++++++++++++++++++++++++++++++++++++++++++-----
>   2 files changed, 75 insertions(+), 6 deletions(-)
>
> diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
> index 5c17b1f..b8f0269 100644
> --- a/include/net/cfg80211.h
> +++ b/include/net/cfg80211.h
> @@ -2950,6 +2950,19 @@ struct wiphy_vendor_command {
>    *	low rssi when a frame is heard on different channel, then it should set
>    *	this variable to the maximal offset for which it can compensate.
>    *	This value should be set in MHz.
> + * @get_regd: a driver callback to for publishing regulatory information.
> + *	By implementing this callback, a wiphy indicates it will provide
> + *	regulatory information. The callback must be set before the wiphy is
> + *	is registered. Only the first wiphy with this callback will be called
> + *	to provide a regdomain on country-code changes.
> + *	Returns A driver allocated regdomain structure. The alpha2 in the
> + *	returned regdomain can be different from the one given via the alpha2
> + *	argument, if the argument contains "99", meaning unknown.
> + *	If an ERR_PTR is returned the regulatory core will consult other
> + *	sources for the regdomain info (internal regdb and CRDA). Returning
> + *	NULL will cause the regdomain to remain the same. The callee will
> + *	return a struct allocated with kmalloc(). After the struct is returned,
> + *	the regulatory core is responsible for freeing it.
>    */
>   struct wiphy {
>   	/* assign these fields before you register the wiphy */
> @@ -3033,6 +3046,9 @@ struct wiphy {
>   	void (*reg_notifier)(struct wiphy *wiphy,
>   			     struct regulatory_request *request);
>
> +	struct ieee80211_regdomain * (*get_regd)(struct wiphy *wiphy,
> +						 const char *alpha2);
> +
>   	/* fields below are read-only, assigned by cfg80211 */
>
>   	const struct ieee80211_regdomain __rcu *regd;
> diff --git a/net/wireless/reg.c b/net/wireless/reg.c
> index efd6d0d..e2f33d7 100644
> --- a/net/wireless/reg.c
> +++ b/net/wireless/reg.c
> @@ -78,6 +78,8 @@
>    *	further processing is required, i.e., not need to update last_request
>    *	etc. This should be used for user hints that do not provide an alpha2
>    *	but some other type of regulatory hint, i.e., indoor operation.
> + * @REG_REQ_HANDLED: a request was handled synchronously. No need to set
> + *	timeouts and potentially revert to the default settings.
>    */
>   enum reg_request_treatment {
>   	REG_REQ_OK,
> @@ -85,6 +87,7 @@ enum reg_request_treatment {
>   	REG_REQ_INTERSECT,
>   	REG_REQ_ALREADY_SET,
>   	REG_REQ_USER_HINT_HANDLED,
> +	REG_REQ_HANDLED,
>   };
>
>   static struct regulatory_request core_request_world = {
> @@ -129,6 +132,15 @@ static int reg_num_devs_support_basehint;
>    */
>   static bool reg_is_indoor;
>
> +/*
> + * Wiphy with a get_regd() callback that can provide regulatory information
> + * when the country code changes. Only the first wiphy registered with the
> + * get_regd callback will be called to provide a regdomain on country-code
> + * changes.
> + * (protected by RTNL)
> + */
> +static struct wiphy *regd_info_wiphy;
> +
>   static const struct ieee80211_regdomain *get_cfg80211_regdom(void)
>   {
>   	return rtnl_dereference(cfg80211_regdomain);
> @@ -538,9 +550,39 @@ static int call_crda(const char *alpha2)
>   	return kobject_uevent_env(&reg_pdev->dev.kobj, KOBJ_CHANGE, env);
>   }
>
> +static int call_wiphy_regd_info(const char *alpha2)
> +{
> +	struct ieee80211_regdomain *regd;
> +
> +	if (!regd_info_wiphy)
> +		return -ENOENT;
> +
> +	/* can happen if the driver removes the callback at runtime */
> +	if (WARN_ON(!regd_info_wiphy->get_regd))
> +		return -EINVAL;
> +
> +	regd = regd_info_wiphy->get_regd(regd_info_wiphy, alpha2);
> +	if (IS_ERR(regd))
> +		return -EIO;
> +
> +	if (regd)
> +		set_regdom(regd);
> +
> +	return 0;
> +}
> +
>   static enum reg_request_treatment
> -reg_call_crda(struct regulatory_request *request)
> +reg_get_regdom_data(struct regulatory_request *request)
>   {
> +	ASSERT_RTNL();
> +
> +	/*
> +	 * A wiphy wishing to set the regdomain takes precedence. Note the
> +	 * regdomain setting happens synchronously inside.
> +	 */
> +	if (!call_wiphy_regd_info(request->alpha2))
> +		return REG_REQ_HANDLED;
> +
>   	if (call_crda(request->alpha2))
>   		return REG_REQ_IGNORE;
>   	return REG_REQ_OK;
> @@ -1641,7 +1683,7 @@ reg_process_hint_core(struct regulatory_request *core_request)
>
>   	reg_update_last_request(core_request);
>
> -	return reg_call_crda(core_request);
> +	return reg_get_regdom_data(core_request);
>   }
>
>   static enum reg_request_treatment
> @@ -1715,7 +1757,7 @@ reg_process_hint_user(struct regulatory_request *user_request)
>   	user_alpha2[0] = user_request->alpha2[0];
>   	user_alpha2[1] = user_request->alpha2[1];
>
> -	return reg_call_crda(user_request);
> +	return reg_get_regdom_data(user_request);
>   }
>
>   static enum reg_request_treatment
> @@ -1764,6 +1806,7 @@ reg_process_hint_driver(struct wiphy *wiphy,
>   		break;
>   	case REG_REQ_IGNORE:
>   	case REG_REQ_USER_HINT_HANDLED:
> +	case REG_REQ_HANDLED:
>   		reg_free_request(driver_request);
>   		return treatment;
>   	case REG_REQ_INTERSECT:
> @@ -1794,7 +1837,7 @@ reg_process_hint_driver(struct wiphy *wiphy,
>   		return treatment;
>   	}
>
> -	return reg_call_crda(driver_request);
> +	return reg_get_regdom_data(driver_request);
>   }
>
>   static enum reg_request_treatment
> @@ -1864,6 +1907,7 @@ reg_process_hint_country_ie(struct wiphy *wiphy,
>   		break;
>   	case REG_REQ_IGNORE:
>   	case REG_REQ_USER_HINT_HANDLED:
> +	case REG_REQ_HANDLED:
>   		/* fall through */
>   	case REG_REQ_ALREADY_SET:
>   		reg_free_request(country_ie_request);
> @@ -1883,7 +1927,7 @@ reg_process_hint_country_ie(struct wiphy *wiphy,
>
>   	reg_update_last_request(country_ie_request);
>
> -	return reg_call_crda(country_ie_request);
> +	return reg_get_regdom_data(country_ie_request);
>   }
>
>   /* This processes *all* regulatory hints */
> @@ -1903,7 +1947,8 @@ static void reg_process_hint(struct regulatory_request *reg_request)
>   		treatment = reg_process_hint_user(reg_request);
>   		if (treatment == REG_REQ_IGNORE ||
>   		    treatment == REG_REQ_ALREADY_SET ||
> -		    treatment == REG_REQ_USER_HINT_HANDLED)
> +		    treatment == REG_REQ_USER_HINT_HANDLED ||
> +		    treatment == REG_REQ_HANDLED)
>   			return;
>   		queue_delayed_work(system_power_efficient_wq,
>   				   &reg_timeout, msecs_to_jiffies(3142));
> @@ -2684,6 +2729,9 @@ void wiphy_regulatory_register(struct wiphy *wiphy)
>   {
>   	struct regulatory_request *lr;
>
> +	if (wiphy->get_regd && !regd_info_wiphy)
> +		regd_info_wiphy = wiphy;
> +
>   	if (!reg_dev_ignore_cell_hint(wiphy))
>   		reg_num_devs_support_basehint++;
>
> @@ -2696,6 +2744,8 @@ void wiphy_regulatory_deregister(struct wiphy *wiphy)
>   	struct wiphy *request_wiphy = NULL;
>   	struct regulatory_request *lr;
>
> +	ASSERT_RTNL();
> +
>   	lr = get_last_request();
>
>   	if (!reg_dev_ignore_cell_hint(wiphy))
> @@ -2704,6 +2754,9 @@ void wiphy_regulatory_deregister(struct wiphy *wiphy)
>   	rcu_free_regdom(get_wiphy_regdom(wiphy));
>   	RCU_INIT_POINTER(wiphy->regd, NULL);
>
> +	if (wiphy == regd_info_wiphy)
> +		regd_info_wiphy = NULL;
> +
>   	if (lr)
>   		request_wiphy = wiphy_idx_to_wiphy(lr->wiphy_idx);
>
>