This adds a helper function that, given a bitmap of basic rates and a bitrate returns the response rate for this rate. Signed-off-by: Johannes Berg <johannes@xxxxxxxxxxxxxxxx> --- include/net/wireless.h | 16 ++++++++++++++++ net/wireless/util.c | 19 +++++++++++++++++++ 2 files changed, 35 insertions(+) --- everything.orig/net/wireless/util.c 2008-10-29 19:16:26.000000000 +0100 +++ everything/net/wireless/util.c 2008-10-29 19:16:54.000000000 +0100 @@ -7,6 +7,25 @@ #include <asm/bitops.h> #include "core.h" +struct ieee80211_rate * +ieee80211_get_response_rate(struct ieee80211_supported_band *sband, + u64 basic_rates, int bitrate) +{ + struct ieee80211_rate *result = &sband->bitrates[0]; + int i; + + for (i = 0; i < sband->n_bitrates; i++) { + if (!(basic_rates & BIT(i))) + continue; + if (sband->bitrates[i].bitrate > bitrate) + continue; + result = &sband->bitrates[i]; + } + + return result; +} +EXPORT_SYMBOL(ieee80211_get_response_rate); + int ieee80211_channel_to_frequency(int chan) { if (chan < 14) --- everything.orig/include/net/wireless.h 2008-10-29 19:16:26.000000000 +0100 +++ everything/include/net/wireless.h 2008-10-29 19:16:47.000000000 +0100 @@ -341,6 +341,22 @@ ieee80211_get_channel(struct wiphy *wiph } /** + * ieee80211_get_response_rate - get basic rate for a given rate + * + * @sband: the band to look for rates in + * @basic_rates: bitmap of basic rates + * @bitrate: the bitrate for which to find the basic rate + * + * This function returns the basic rate corresponding to a given + * bitrate, that is the next lower bitrate contained in the basic + * rate map, which is, for this function, given as a bitmap of + * indices of rates in the band's bitrate table. + */ +struct ieee80211_rate * +ieee80211_get_response_rate(struct ieee80211_supported_band *sband, + u64 basic_rates, int bitrate); + +/** * regulatory_hint - driver hint to the wireless core a regulatory domain * @wiphy: the wireless device giving the hint (used only for reporting * conflicts) -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html