iwlwifi: move channel switch related functions

With the creation of iwl-agn-devices.c,
iwl-core.c can be cleaned up a bit more by
moving beacon time related functions from
iwl-core.c to iwl-agn-devices.c

Signed-off-by: Meenakshi Venkataraman <meenakshi.venkataraman@intel.com>
Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
diff --git a/drivers/net/wireless/iwlwifi/iwl-agn-devices.c b/drivers/net/wireless/iwlwifi/iwl-agn-devices.c
index bc9cb5c..08718ca 100644
--- a/drivers/net/wireless/iwlwifi/iwl-agn-devices.c
+++ b/drivers/net/wireless/iwlwifi/iwl-agn-devices.c
@@ -71,6 +71,80 @@
 				~APMG_SVR_VOLTAGE_CONFIG_BIT_MSK);
 }
 
+/**
+ * iwl_beacon_time_mask_low - mask of lower 32 bit of beacon time
+ * @priv -- pointer to iwl_priv data structure
+ * @tsf_bits -- number of bits need to shift for masking)
+ */
+static inline u32 iwl_beacon_time_mask_low(struct iwl_priv *priv,
+					   u16 tsf_bits)
+{
+	return (1 << tsf_bits) - 1;
+}
+
+/**
+ * iwl_beacon_time_mask_high - mask of higher 32 bit of beacon time
+ * @priv -- pointer to iwl_priv data structure
+ * @tsf_bits -- number of bits need to shift for masking)
+ */
+static inline u32 iwl_beacon_time_mask_high(struct iwl_priv *priv,
+					    u16 tsf_bits)
+{
+	return ((1 << (32 - tsf_bits)) - 1) << tsf_bits;
+}
+
+/*
+ * extended beacon time format
+ * time in usec will be changed into a 32-bit value in extended:internal format
+ * the extended part is the beacon counts
+ * the internal part is the time in usec within one beacon interval
+ */
+static u32 iwl_usecs_to_beacons(struct iwl_priv *priv, u32 usec,
+				u32 beacon_interval)
+{
+	u32 quot;
+	u32 rem;
+	u32 interval = beacon_interval * TIME_UNIT;
+
+	if (!interval || !usec)
+		return 0;
+
+	quot = (usec / interval) &
+		(iwl_beacon_time_mask_high(priv, IWLAGN_EXT_BEACON_TIME_POS) >>
+		IWLAGN_EXT_BEACON_TIME_POS);
+	rem = (usec % interval) & iwl_beacon_time_mask_low(priv,
+				   IWLAGN_EXT_BEACON_TIME_POS);
+
+	return (quot << IWLAGN_EXT_BEACON_TIME_POS) + rem;
+}
+
+/* base is usually what we get from ucode with each received frame,
+ * the same as HW timer counter counting down
+ */
+static __le32 iwl_add_beacon_time(struct iwl_priv *priv, u32 base,
+			   u32 addon, u32 beacon_interval)
+{
+	u32 base_low = base & iwl_beacon_time_mask_low(priv,
+				IWLAGN_EXT_BEACON_TIME_POS);
+	u32 addon_low = addon & iwl_beacon_time_mask_low(priv,
+				IWLAGN_EXT_BEACON_TIME_POS);
+	u32 interval = beacon_interval * TIME_UNIT;
+	u32 res = (base & iwl_beacon_time_mask_high(priv,
+				IWLAGN_EXT_BEACON_TIME_POS)) +
+				(addon & iwl_beacon_time_mask_high(priv,
+				IWLAGN_EXT_BEACON_TIME_POS));
+
+	if (base_low > addon_low)
+		res += base_low - addon_low;
+	else if (base_low < addon_low) {
+		res += interval + base_low - addon_low;
+		res += (1 << IWLAGN_EXT_BEACON_TIME_POS);
+	} else
+		res += (1 << IWLAGN_EXT_BEACON_TIME_POS);
+
+	return cpu_to_le32(res);
+}
+
 static const struct iwl_sensitivity_ranges iwl1000_sensitivity = {
 	.min_nrg_cck = 95,
 	.auto_corr_min_ofdm = 90,