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, 86 insertions, 6 deletions

diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index e288fdcb3df2..a82fc59a1d82 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -128,6 +128,7 @@ enum ieee80211_channel_flags {
  * with cfg80211.
  *
  * @center_freq: center frequency in MHz
+ * @freq_offset: offset from @center_freq, in KHz
  * @hw_value: hardware-specific value for the channel
  * @flags: channel flags from &enum ieee80211_channel_flags.
  * @orig_flags: channel flags at registration time, used by regulatory
@@ -149,6 +150,7 @@ enum ieee80211_channel_flags {
 struct ieee80211_channel {
 	enum nl80211_band band;
 	u32 center_freq;
+	u16 freq_offset;
 	u16 hw_value;
 	u32 flags;
 	int max_antenna_gain;
@@ -617,6 +619,7 @@ struct key_params {
  *	If edmg is requested (i.e. the .channels member is non-zero),
  *	chan will define the primary channel and all other
  *	parameters are ignored.
+ * @freq1_offset: offset from @center_freq1, in KHz
  */
 struct cfg80211_chan_def {
 	struct ieee80211_channel *chan;
@@ -624,6 +627,7 @@ struct cfg80211_chan_def {
 	u32 center_freq1;
 	u32 center_freq2;
 	struct ieee80211_edmg edmg;
+	u16 freq1_offset;
 };
 
 /**
@@ -713,6 +717,7 @@ cfg80211_chandef_identical(const struct cfg80211_chan_def *chandef1,
 	return (chandef1->chan == chandef2->chan &&
 		chandef1->width == chandef2->width &&
 		chandef1->center_freq1 == chandef2->center_freq1 &&
+		chandef1->freq1_offset == chandef2->freq1_offset &&
 		chandef1->center_freq2 == chandef2->center_freq2);
 }
 
@@ -5178,29 +5183,91 @@ static inline void *wdev_priv(struct wireless_dev *wdev)
  */
 
 /**
+ * ieee80211_channel_equal - compare two struct ieee80211_channel
+ *
+ * @a: 1st struct ieee80211_channel
+ * @b: 2nd struct ieee80211_channel
+ * Return: true if center frequency of @a == @b
+ */
+static inline bool
+ieee80211_channel_equal(struct ieee80211_channel *a,
+			struct ieee80211_channel *b)
+{
+	return (a->center_freq == b->center_freq &&
+		a->freq_offset == b->freq_offset);
+}
+
+/**
+ * ieee80211_channel_to_khz - convert ieee80211_channel to frequency in KHz
+ * @chan: struct ieee80211_channel to convert
+ * Return: The corresponding frequency (in KHz)
+ */
+static inline u32
+ieee80211_channel_to_khz(const struct ieee80211_channel *chan)
+{
+	return MHZ_TO_KHZ(chan->center_freq) + chan->freq_offset;
+}
+
+/**
+ * ieee80211_channel_to_freq_khz - convert channel number to frequency
+ * @chan: channel number
+ * @band: band, necessary due to channel number overlap
+ * Return: The corresponding frequency (in KHz), or 0 if the conversion failed.
+ */
+u32 ieee80211_channel_to_freq_khz(int chan, enum nl80211_band band);
+
+/**
  * ieee80211_channel_to_frequency - convert channel number to frequency
  * @chan: channel number
  * @band: band, necessary due to channel number overlap
  * Return: The corresponding frequency (in MHz), or 0 if the conversion failed.
  */
-int ieee80211_channel_to_frequency(int chan, enum nl80211_band band);
+static inline int
+ieee80211_channel_to_frequency(int chan, enum nl80211_band band)
+{
+	return KHZ_TO_MHZ(ieee80211_channel_to_freq_khz(chan, band));
+}
+
+/**
+ * ieee80211_freq_khz_to_channel - convert frequency to channel number
+ * @freq: center frequency in KHz
+ * Return: The corresponding channel, or 0 if the conversion failed.
+ */
+int ieee80211_freq_khz_to_channel(u32 freq);
 
 /**
  * ieee80211_frequency_to_channel - convert frequency to channel number
- * @freq: center frequency
+ * @freq: center frequency in MHz
  * Return: The corresponding channel, or 0 if the conversion failed.
  */
-int ieee80211_frequency_to_channel(int freq);
+static inline int
+ieee80211_frequency_to_channel(int freq)
+{
+	return ieee80211_freq_khz_to_channel(MHZ_TO_KHZ(freq));
+}
+
+/**
+ * ieee80211_get_channel_khz - get channel struct from wiphy for specified
+ * frequency
+ * @wiphy: the struct wiphy to get the channel for
+ * @freq: the center frequency (in KHz) of the channel
+ * Return: The channel struct from @wiphy at @freq.
+ */
+struct ieee80211_channel *
+ieee80211_get_channel_khz(struct wiphy *wiphy, u32 freq);
 
 /**
  * ieee80211_get_channel - get channel struct from wiphy for specified frequency
  *
  * @wiphy: the struct wiphy to get the channel for
- * @freq: the center frequency of the channel
- *
+ * @freq: the center frequency (in MHz) of the channel
  * Return: The channel struct from @wiphy at @freq.
  */
-struct ieee80211_channel *ieee80211_get_channel(struct wiphy *wiphy, int freq);
+static inline struct ieee80211_channel *
+ieee80211_get_channel(struct wiphy *wiphy, int freq)
+{
+	return ieee80211_get_channel_khz(wiphy, MHZ_TO_KHZ(freq));
+}
 
 /**
  * ieee80211_get_response_rate - get basic rate for a given rate
@@ -7228,6 +7295,19 @@ bool ieee80211_operating_class_to_band(u8 operating_class,
 bool ieee80211_chandef_to_operating_class(struct cfg80211_chan_def *chandef,
 					  u8 *op_class);
 
+/**
+ * ieee80211_chandef_to_khz - convert chandef to frequency in KHz
+ *
+ * @chandef: the chandef to convert
+ *
+ * Returns the center frequency of chandef (1st segment) in KHz.
+ */
+static inline u32
+ieee80211_chandef_to_khz(const struct cfg80211_chan_def *chandef)
+{
+	return MHZ_TO_KHZ(chandef->center_freq1) + chandef->freq1_offset;
+}
+
 /*
  * cfg80211_tdls_oper_request - request userspace to perform TDLS operation
  * @dev: the device on which the operation is requested