wireless: Add channel/frequency conversions to ieee80211.h

Added mappings for FHSS, DSSS and OFDM channels - with macros to point
HR DSSS and ERP to the DSSS mappings. Currently just static inline
functions.

Use the new functions in the older fullmac drivers. This eliminates a
number of const static buffers and removes a couple of range checks that
are now redundant.

Signed-off-by: David Kilroy <kilroyd@googlemail.com>
Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Richard Farina <sidhayn@gmail.com>
Acked-by: Jeroen Vreeken <pe1rxq@amsat.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

include/linux/ieee80211.h

@@ -1185,4 +1185,120 @@ static inline u8 *ieee80211_get_DA(struct ieee80211_hdr *hdr)
 		return hdr->addr1;
 }
 
+/**
+ * ieee80211_fhss_chan_to_freq - get channel frequency
+ * @channel: the FHSS channel
+ *
+ * Convert IEEE802.11 FHSS channel to frequency (MHz)
+ * Ref IEEE 802.11-2007 section 14.6
+ */
+static inline int ieee80211_fhss_chan_to_freq(int channel)
+{
+	if ((channel > 1) && (channel < 96))
+		return channel + 2400;
+	else
+		return -1;
+}
+
+/**
+ * ieee80211_freq_to_fhss_chan - get channel
+ * @freq: the channels frequency
+ *
+ * Convert frequency (MHz) to IEEE802.11 FHSS channel
+ * Ref IEEE 802.11-2007 section 14.6
+ */
+static inline int ieee80211_freq_to_fhss_chan(int freq)
+{
+	if ((freq > 2401) && (freq < 2496))
+		return freq - 2400;
+	else
+		return -1;
+}
+
+/**
+ * ieee80211_dsss_chan_to_freq - get channel center frequency
+ * @channel: the DSSS channel
+ *
+ * Convert IEEE802.11 DSSS channel to the center frequency (MHz).
+ * Ref IEEE 802.11-2007 section 15.6
+ */
+static inline int ieee80211_dsss_chan_to_freq(int channel)
+{
+	if ((channel > 0) && (channel < 14))
+		return 2407 + (channel * 5);
+	else if (channel == 14)
+		return 2484;
+	else
+		return -1;
+}
+
+/**
+ * ieee80211_freq_to_dsss_chan - get channel
+ * @freq: the frequency
+ *
+ * Convert frequency (MHz) to IEEE802.11 DSSS channel
+ * Ref IEEE 802.11-2007 section 15.6
+ *
+ * This routine selects the channel with the closest center frequency.
+ */
+static inline int ieee80211_freq_to_dsss_chan(int freq)
+{
+	if ((freq >= 2410) && (freq < 2475))
+		return (freq - 2405) / 5;
+	else if ((freq >= 2482) && (freq < 2487))
+		return 14;
+	else
+		return -1;
+}
+
+/* Convert IEEE802.11 HR DSSS channel to frequency (MHz) and back
+ * Ref IEEE 802.11-2007 section 18.4.6.2
+ *
+ * The channels and frequencies are the same as those defined for DSSS
+ */
+#define ieee80211_hr_chan_to_freq(chan) ieee80211_dsss_chan_to_freq(chan)
+#define ieee80211_freq_to_hr_chan(freq) ieee80211_freq_to_dsss_chan(freq)
+
+/* Convert IEEE802.11 ERP channel to frequency (MHz) and back
+ * Ref IEEE 802.11-2007 section 19.4.2
+ */
+#define ieee80211_erp_chan_to_freq(chan) ieee80211_hr_chan_to_freq(chan)
+#define ieee80211_freq_to_erp_chan(freq) ieee80211_freq_to_hr_chan(freq)
+
+/**
+ * ieee80211_ofdm_chan_to_freq - get channel center frequency
+ * @s_freq: starting frequency == (dotChannelStartingFactor/2) MHz
+ * @channel: the OFDM channel
+ *
+ * Convert IEEE802.11 OFDM channel to center frequency (MHz)
+ * Ref IEEE 802.11-2007 section 17.3.8.3.2
+ */
+static inline int ieee80211_ofdm_chan_to_freq(int s_freq, int channel)
+{
+	if ((channel > 0) && (channel <= 200) &&
+	    (s_freq >= 4000))
+		return s_freq + (channel * 5);
+	else
+		return -1;
+}
+
+/**
+ * ieee80211_freq_to_ofdm_channel - get channel
+ * @s_freq: starting frequency == (dotChannelStartingFactor/2) MHz
+ * @freq: the frequency
+ *
+ * Convert frequency (MHz) to IEEE802.11 OFDM channel
+ * Ref IEEE 802.11-2007 section 17.3.8.3.2
+ *
+ * This routine selects the channel with the closest center frequency.
+ */
+static inline int ieee80211_freq_to_ofdm_chan(int s_freq, int freq)
+{
+	if ((freq > (s_freq + 2)) && (freq <= (s_freq + 1202)) &&
+	    (s_freq >= 4000))
+		return (freq + 2 - s_freq) / 5;
+	else
+		return -1;
+}
+
 #endif /* LINUX_IEEE80211_H */