iwlwifi: add comments to RXON command and txpower formats

Add comments to RXON command and txpower formats

Signed-off-by: Ben Cahill <ben.m.cahill@intel.com>
Signed-off-by: Zhu Yi <yi.zhu@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

2 files changed, 124 insertions, 42 deletions

diff --git a/drivers/net/wireless/iwlwifi/iwl-3945-commands.h b/drivers/net/wireless/iwlwifi/iwl-3945-commands.h
index 3d3c7e3..4a8fc68 100644
--- a/drivers/net/wireless/iwlwifi/iwl-3945-commands.h
+++ b/drivers/net/wireless/iwlwifi/iwl-3945-commands.h
@@ -124,7 +124,7 @@ enum {
 	/* Bluetooth device coexistance config command */
 	REPLY_BT_CONFIG = 0x9b,
 
-	/* 4965 Statistics */
+	/* Statistics */
 	REPLY_STATISTICS_CMD = 0x9c,
 	STATISTICS_NOTIFICATION = 0x9d,
 
@@ -140,7 +140,8 @@ enum {
 
 /******************************************************************************
  * (0)
- * Header
+ * Commonly used structures and definitions:
+ * Command header, txpower
  *
  *****************************************************************************/
 
@@ -183,6 +184,36 @@ struct iwl3945_cmd_header {
 	u8 data[0];
 } __attribute__ ((packed));
 
+/**
+ * struct iwl3945_tx_power
+ *
+ * Used in REPLY_TX_PWR_TABLE_CMD, REPLY_SCAN_CMD, REPLY_CHANNEL_SWITCH
+ *
+ * Each entry contains two values:
+ * 1)  DSP gain (or sometimes called DSP attenuation).  This is a fine-grained
+ *     linear value that multiplies the output of the digital signal processor,
+ *     before being sent to the analog radio.
+ * 2)  Radio gain.  This sets the analog gain of the radio Tx path.
+ *     It is a coarser setting, and behaves in a logarithmic (dB) fashion.
+ *
+ * Driver obtains values from struct iwl3945_tx_power power_gain_table[][].
+ */
+struct iwl3945_tx_power {
+	u8 tx_gain;		/* gain for analog radio */
+	u8 dsp_atten;		/* gain for DSP */
+} __attribute__ ((packed));
+
+/**
+ * struct iwl3945_power_per_rate
+ *
+ * Used in REPLY_TX_PWR_TABLE_CMD, REPLY_CHANNEL_SWITCH
+ */
+struct iwl3945_power_per_rate {
+	u8 rate;		/* plcp */
+	struct iwl3945_tx_power tpc;
+	u8 reserved;
+} __attribute__ ((packed));
+
 /******************************************************************************
  * (0a)
  * Alive and Error Commands & Responses:
@@ -328,8 +359,22 @@ enum {
 /* transfer to host non bssid beacons in associated state */
 #define RXON_FILTER_BCON_AWARE_MSK      __constant_cpu_to_le32(1 << 6)
 
-/*
+/**
  * REPLY_RXON = 0x10 (command, has simple generic response)
+ *
+ * RXON tunes the radio tuner to a service channel, and sets up a number
+ * of parameters that are used primarily for Rx, but also for Tx operations.
+ *
+ * NOTE:  When tuning to a new channel, driver must set the
+ *        RXON_FILTER_ASSOC_MSK to 0.  This will clear station-dependent
+ *        info within the device, including the station tables, tx retry
+ *        rate tables, and txpower tables.  Driver must build a new station
+ *        table and txpower table before transmitting anything on the RXON
+ *        channel.
+ *
+ * NOTE:  All RXONs wipe clean the internal txpower table.  Driver must
+ *        issue a new REPLY_TX_PWR_TABLE_CMD after each REPLY_RXON (0x10),
+ *        regardless of whether RXON_FILTER_ASSOC_MSK is set.
  */
 struct iwl3945_rxon_cmd {
 	u8 node_addr[6];
@@ -373,17 +418,6 @@ struct iwl3945_rxon_time_cmd {
 	__le16 reserved;
 } __attribute__ ((packed));
 
-struct iwl3945_tx_power {
-	u8 tx_gain;		/* gain for analog radio */
-	u8 dsp_atten;		/* gain for DSP */
-} __attribute__ ((packed));
-
-struct iwl3945_power_per_rate {
-	u8 rate;		/* plcp */
-	struct iwl3945_tx_power tpc;
-	u8 reserved;
-} __attribute__ ((packed));
-
 /*
  * REPLY_CHANNEL_SWITCH = 0x72 (command, has simple generic response)
  */
diff --git a/drivers/net/wireless/iwlwifi/iwl-4965-commands.h b/drivers/net/wireless/iwlwifi/iwl-4965-commands.h
index bde3aa0..0813e3e 100644
--- a/drivers/net/wireless/iwlwifi/iwl-4965-commands.h
+++ b/drivers/net/wireless/iwlwifi/iwl-4965-commands.h
@@ -123,7 +123,7 @@ enum {
 	/* Bluetooth device coexistance config command */
 	REPLY_BT_CONFIG = 0x9b,
 
-	/* 4965 Statistics */
+	/* Statistics */
 	REPLY_STATISTICS_CMD = 0x9c,
 	STATISTICS_NOTIFICATION = 0x9d,
 
@@ -147,7 +147,7 @@ enum {
 /******************************************************************************
  * (0)
  * Commonly used structures and definitions:
- * Command header, rate_n_flags
+ * Command header, rate_n_flags, txpower
  *
  *****************************************************************************/
 
@@ -273,6 +273,65 @@ struct iwl4965_cmd_header {
 #define RATE_MCS_ANT_AB_MSK	0xc000
 
 
+/**
+ * struct iwl4965_tx_power - txpower format used in REPLY_SCAN_CMD
+ *
+ * Scan uses only one transmitter, so only one analog/dsp gain pair is needed.
+ */
+struct iwl4965_tx_power {
+	u8 tx_gain;		/* gain for analog radio */
+	u8 dsp_atten;		/* gain for DSP */
+} __attribute__ ((packed));
+
+#define POWER_TABLE_NUM_ENTRIES			33
+#define POWER_TABLE_NUM_HT_OFDM_ENTRIES		32
+#define POWER_TABLE_CCK_ENTRY			32
+
+/**
+ * union iwl4965_tx_power_dual_stream
+ *
+ * Host format used for REPLY_TX_PWR_TABLE_CMD, REPLY_CHANNEL_SWITCH
+ * Use __le32 version (struct tx_power_dual_stream) when building command.
+ *
+ * Driver provides radio gain and DSP attenuation settings to device in pairs,
+ * one value for each transmitter chain.  The first value is for transmitter A,
+ * second for transmitter B.
+ *
+ * For SISO bit rates, both values in a pair should be identical.
+ * For MIMO rates, one value may be different from the other,
+ * in order to balance the Tx output between the two transmitters.
+ *
+ * See more details in doc for TXPOWER in iwl-4965-hw.h.
+ */
+union iwl4965_tx_power_dual_stream {
+	struct {
+		u8 radio_tx_gain[2];
+		u8 dsp_predis_atten[2];
+	} s;
+	u32 dw;
+};
+
+/**
+ * struct tx_power_dual_stream
+ *
+ * Table entries in REPLY_TX_PWR_TABLE_CMD, REPLY_CHANNEL_SWITCH
+ *
+ * Same format as iwl_tx_power_dual_stream, but __le32
+ */
+struct tx_power_dual_stream {
+	__le32 dw;
+} __attribute__ ((packed));
+
+/**
+ * struct iwl4965_tx_power_db
+ *
+ * Entire table within REPLY_TX_PWR_TABLE_CMD, REPLY_CHANNEL_SWITCH
+ */
+struct iwl4965_tx_power_db {
+	struct tx_power_dual_stream power_tbl[POWER_TABLE_NUM_ENTRIES];
+} __attribute__ ((packed));
+
+
 /******************************************************************************
  * (0a)
  * Alive and Error Commands & Responses:
@@ -501,8 +560,22 @@ enum {
 /* transfer to host non bssid beacons in associated state */
 #define RXON_FILTER_BCON_AWARE_MSK      __constant_cpu_to_le32(1 << 6)
 
-/*
+/**
  * REPLY_RXON = 0x10 (command, has simple generic response)
+ *
+ * RXON tunes the radio tuner to a service channel, and sets up a number
+ * of parameters that are used primarily for Rx, but also for Tx operations.
+ *
+ * NOTE:  When tuning to a new channel, driver must set the
+ *        RXON_FILTER_ASSOC_MSK to 0.  This will clear station-dependent
+ *        info within the device, including the station tables, tx retry
+ *        rate tables, and txpower tables.  Driver must build a new station
+ *        table and txpower table before transmitting anything on the RXON
+ *        channel.
+ *
+ * NOTE:  All RXONs wipe clean the internal txpower table.  Driver must
+ *        issue a new REPLY_TX_PWR_TABLE_CMD after each REPLY_RXON (0x10),
+ *        regardless of whether RXON_FILTER_ASSOC_MSK is set.
  */
 struct iwl4965_rxon_cmd {
 	u8 node_addr[6];
@@ -550,31 +623,6 @@ struct iwl4965_rxon_time_cmd {
 	__le16 reserved;
 } __attribute__ ((packed));
 
-struct iwl4965_tx_power {
-	u8 tx_gain;		/* gain for analog radio */
-	u8 dsp_atten;		/* gain for DSP */
-} __attribute__ ((packed));
-
-#define POWER_TABLE_NUM_ENTRIES			33
-#define POWER_TABLE_NUM_HT_OFDM_ENTRIES		32
-#define POWER_TABLE_CCK_ENTRY			32
-
-union iwl4965_tx_power_dual_stream {
-	struct {
-		u8 radio_tx_gain[2];
-		u8 dsp_predis_atten[2];
-	} s;
-	u32 dw;
-};
-
-struct tx_power_dual_stream {
-	__le32 dw;
-} __attribute__ ((packed));
-
-struct iwl4965_tx_power_db {
-	struct tx_power_dual_stream power_tbl[POWER_TABLE_NUM_ENTRIES];
-} __attribute__ ((packed));
-
 /*
  * REPLY_CHANNEL_SWITCH = 0x72 (command, has simple generic response)
  */