cfg80211: express channels with a KHz component

Some bands (S1G) define channels centered on a non-integer
MHz. Give ieee80211_channel and cfg80211_chan_def a
freq_offset component where the final frequency can be
expressed as:

MHZ_TO_KHZ(chan->center_freq) + chan->freq_offset;

Also provide some helper functions to do the frequency
conversion and test for equality.

Retain the existing interface to frequency and channel
conversion helpers, and expose new ones which handle
frequencies in units of KHz.

Some internal functions (net/wireless/chan.c) pass around
a frequency value. Convert these to units of KHz.

mesh, ibss, wext, etc. are currently ignored.

Signed-off-by: Thomas Pedersen <thomas@adapt-ip.com>
Link: https://lore.kernel.org/r/20200402011810.22947-3-thomas@adapt-ip.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 21 insertions, 19 deletions

diff --git a/net/wireless/reg.c b/net/wireless/reg.c
index d476d4da0d09..0d74a31ef0ab 100644
--- a/net/wireless/reg.c
+++ b/net/wireless/reg.c
@@ -1658,22 +1658,23 @@ static uint32_t reg_rule_to_chan_bw_flags(const struct ieee80211_regdomain *regd
 					  const struct ieee80211_channel *chan)
 {
 	const struct ieee80211_freq_range *freq_range = NULL;
-	u32 max_bandwidth_khz, bw_flags = 0;
+	u32 max_bandwidth_khz, center_freq_khz, bw_flags = 0;
 
 	freq_range = &reg_rule->freq_range;
 
 	max_bandwidth_khz = freq_range->max_bandwidth_khz;
+	center_freq_khz = ieee80211_channel_to_khz(chan);
 	/* Check if auto calculation requested */
 	if (reg_rule->flags & NL80211_RRF_AUTO_BW)
 		max_bandwidth_khz = reg_get_max_bandwidth(regd, reg_rule);
 
 	/* If we get a reg_rule we can assume that at least 5Mhz fit */
 	if (!cfg80211_does_bw_fit_range(freq_range,
-					MHZ_TO_KHZ(chan->center_freq),
+					center_freq_khz,
 					MHZ_TO_KHZ(10)))
 		bw_flags |= IEEE80211_CHAN_NO_10MHZ;
 	if (!cfg80211_does_bw_fit_range(freq_range,
-					MHZ_TO_KHZ(chan->center_freq),
+					center_freq_khz,
 					MHZ_TO_KHZ(20)))
 		bw_flags |= IEEE80211_CHAN_NO_20MHZ;
 
@@ -1710,7 +1711,7 @@ static void handle_channel(struct wiphy *wiphy,
 
 	flags = chan->orig_flags;
 
-	reg_rule = freq_reg_info(wiphy, MHZ_TO_KHZ(chan->center_freq));
+	reg_rule = freq_reg_info(wiphy, ieee80211_channel_to_khz(chan));
 	if (IS_ERR(reg_rule)) {
 		/*
 		 * We will disable all channels that do not match our
@@ -1729,13 +1730,13 @@ static void handle_channel(struct wiphy *wiphy,
 		if (lr->initiator == NL80211_REGDOM_SET_BY_DRIVER &&
 		    request_wiphy && request_wiphy == wiphy &&
 		    request_wiphy->regulatory_flags & REGULATORY_STRICT_REG) {
-			pr_debug("Disabling freq %d MHz for good\n",
-				 chan->center_freq);
+			pr_debug("Disabling freq %d.%03d MHz for good\n",
+				 chan->center_freq, chan->freq_offset);
 			chan->orig_flags |= IEEE80211_CHAN_DISABLED;
 			chan->flags = chan->orig_flags;
 		} else {
-			pr_debug("Disabling freq %d MHz\n",
-				 chan->center_freq);
+			pr_debug("Disabling freq %d.%03d MHz\n",
+				 chan->center_freq, chan->freq_offset);
 			chan->flags |= IEEE80211_CHAN_DISABLED;
 		}
 		return;
@@ -1936,7 +1937,7 @@ static void handle_reg_beacon(struct wiphy *wiphy, unsigned int chan_idx,
 	sband = wiphy->bands[reg_beacon->chan.band];
 	chan = &sband->channels[chan_idx];
 
-	if (likely(chan->center_freq != reg_beacon->chan.center_freq))
+	if (likely(!ieee80211_channel_equal(chan, &reg_beacon->chan)))
 		return;
 
 	if (chan->beacon_found)
@@ -2269,18 +2270,18 @@ static void handle_channel_custom(struct wiphy *wiphy,
 	u32 bw_flags = 0;
 	const struct ieee80211_reg_rule *reg_rule = NULL;
 	const struct ieee80211_power_rule *power_rule = NULL;
-	u32 bw;
+	u32 bw, center_freq_khz;
 
+	center_freq_khz = ieee80211_channel_to_khz(chan);
 	for (bw = MHZ_TO_KHZ(20); bw >= min_bw; bw = bw / 2) {
-		reg_rule = freq_reg_info_regd(MHZ_TO_KHZ(chan->center_freq),
-					      regd, bw);
+		reg_rule = freq_reg_info_regd(center_freq_khz, regd, bw);
 		if (!IS_ERR(reg_rule))
 			break;
 	}
 
 	if (IS_ERR_OR_NULL(reg_rule)) {
-		pr_debug("Disabling freq %d MHz as custom regd has no rule that fits it\n",
-			 chan->center_freq);
+		pr_debug("Disabling freq %d.%03d MHz as custom regd has no rule that fits it\n",
+			 chan->center_freq, chan->freq_offset);
 		if (wiphy->regulatory_flags & REGULATORY_WIPHY_SELF_MANAGED) {
 			chan->flags |= IEEE80211_CHAN_DISABLED;
 		} else {
@@ -3337,8 +3338,8 @@ static bool pending_reg_beacon(struct ieee80211_channel *beacon_chan)
 	struct reg_beacon *pending_beacon;
 
 	list_for_each_entry(pending_beacon, &reg_pending_beacons, list)
-		if (beacon_chan->center_freq ==
-		    pending_beacon->chan.center_freq)
+		if (ieee80211_channel_equal(beacon_chan,
+					    &pending_beacon->chan))
 			return true;
 	return false;
 }
@@ -3367,9 +3368,10 @@ int regulatory_hint_found_beacon(struct wiphy *wiphy,
 	if (!reg_beacon)
 		return -ENOMEM;
 
-	pr_debug("Found new beacon on frequency: %d MHz (Ch %d) on %s\n",
-		 beacon_chan->center_freq,
-		 ieee80211_frequency_to_channel(beacon_chan->center_freq),
+	pr_debug("Found new beacon on frequency: %d.%03d MHz (Ch %d) on %s\n",
+		 beacon_chan->center_freq, beacon_chan->freq_offset,
+		 ieee80211_freq_khz_to_channel(
+			 ieee80211_channel_to_khz(beacon_chan)),
 		 wiphy_name(wiphy));
 
 	memcpy(&reg_beacon->chan, beacon_chan,