iwlwifi: add comments to Tx commands
Add comments to Tx commands
Clean up unused definitions in iwl-3945-commands.h
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>
diff --git a/drivers/net/wireless/iwlwifi/iwl-4965-commands.h b/drivers/net/wireless/iwlwifi/iwl-4965-commands.h
index 44addea..cbe91db 100644
--- a/drivers/net/wireless/iwlwifi/iwl-4965-commands.h
+++ b/drivers/net/wireless/iwlwifi/iwl-4965-commands.h
@@ -937,8 +937,8 @@
__le16 channel; /* channel number */
__le16 non_cfg_phy[RX_RES_PHY_CNT]; /* upto 14 phy entries */
__le32 reserved2;
- __le32 rate_n_flags;
- __le16 byte_count; /* frame's byte-count */
+ __le32 rate_n_flags; /* RATE_MCS_* */
+ __le16 byte_count; /* frame's byte-count */
__le16 reserved3;
} __attribute__ ((packed));
@@ -952,41 +952,96 @@
* (5)
* Tx Commands & Responses:
*
+ * Driver must place each REPLY_TX command into one of the prioritized Tx
+ * queues in host DRAM, shared between driver and device (see comments for
+ * SCD registers and Tx/Rx Queues). When the device's Tx scheduler and uCode
+ * are preparing to transmit, the device pulls the Tx command over the PCI
+ * bus via one of the device's Tx DMA channels, to fill an internal FIFO
+ * from which data will be transmitted.
+ *
+ * uCode handles all timing and protocol related to control frames
+ * (RTS/CTS/ACK), based on flags in the Tx command. uCode and Tx scheduler
+ * handle reception of block-acks; uCode updates the host driver via
+ * REPLY_COMPRESSED_BA (4965).
+ *
+ * uCode handles retrying Tx when an ACK is expected but not received.
+ * This includes trying lower data rates than the one requested in the Tx
+ * command, as set up by the REPLY_RATE_SCALE (for 3945) or
+ * REPLY_TX_LINK_QUALITY_CMD (4965).
+ *
+ * Driver sets up transmit power for various rates via REPLY_TX_PWR_TABLE_CMD.
+ * This command must be executed after every RXON command, before Tx can occur.
*****************************************************************************/
-/* Tx flags */
+/* REPLY_TX Tx flags field */
+
+/* 1: Use Request-To-Send protocol before this frame.
+ * Mutually exclusive vs. TX_CMD_FLG_CTS_MSK. */
#define TX_CMD_FLG_RTS_MSK __constant_cpu_to_le32(1 << 1)
+
+/* 1: Transmit Clear-To-Send to self before this frame.
+ * Driver should set this for AUTH/DEAUTH/ASSOC-REQ/REASSOC mgmnt frames.
+ * Mutually exclusive vs. TX_CMD_FLG_RTS_MSK. */
#define TX_CMD_FLG_CTS_MSK __constant_cpu_to_le32(1 << 2)
+
+/* 1: Expect ACK from receiving station
+ * 0: Don't expect ACK (MAC header's duration field s/b 0)
+ * Set this for unicast frames, but not broadcast/multicast. */
#define TX_CMD_FLG_ACK_MSK __constant_cpu_to_le32(1 << 3)
+
+/* For 4965:
+ * 1: Use rate scale table (see REPLY_TX_LINK_QUALITY_CMD).
+ * Tx command's initial_rate_index indicates first rate to try;
+ * uCode walks through table for additional Tx attempts.
+ * 0: Use Tx rate/MCS from Tx command's rate_n_flags field.
+ * This rate will be used for all Tx attempts; it will not be scaled. */
#define TX_CMD_FLG_STA_RATE_MSK __constant_cpu_to_le32(1 << 4)
+
+/* 1: Expect immediate block-ack.
+ * Set when Txing a block-ack request frame. Also set TX_CMD_FLG_ACK_MSK. */
#define TX_CMD_FLG_IMM_BA_RSP_MASK __constant_cpu_to_le32(1 << 6)
+
+/* 1: Frame requires full Tx-Op protection.
+ * Set this if either RTS or CTS Tx Flag gets set. */
#define TX_CMD_FLG_FULL_TXOP_PROT_MSK __constant_cpu_to_le32(1 << 7)
+
+/* Tx antenna selection field; used only for 3945, reserved (0) for 4965.
+ * Set field to "0" to allow 3945 uCode to select antenna (normal usage). */
#define TX_CMD_FLG_ANT_SEL_MSK __constant_cpu_to_le32(0xf00)
#define TX_CMD_FLG_ANT_A_MSK __constant_cpu_to_le32(1 << 8)
#define TX_CMD_FLG_ANT_B_MSK __constant_cpu_to_le32(1 << 9)
-/* ucode ignores BT priority for this frame */
+/* 1: Ignore Bluetooth priority for this frame.
+ * 0: Delay Tx until Bluetooth device is done (normal usage). */
#define TX_CMD_FLG_BT_DIS_MSK __constant_cpu_to_le32(1 << 12)
-/* ucode overrides sequence control */
+/* 1: uCode overrides sequence control field in MAC header.
+ * 0: Driver provides sequence control field in MAC header.
+ * Set this for management frames, non-QOS data frames, non-unicast frames,
+ * and also in Tx command embedded in REPLY_SCAN_CMD for active scans. */
#define TX_CMD_FLG_SEQ_CTL_MSK __constant_cpu_to_le32(1 << 13)
-/* signal that this frame is non-last MPDU */
+/* 1: This frame is non-last MPDU; more fragments are coming.
+ * 0: Last fragment, or not using fragmentation. */
#define TX_CMD_FLG_MORE_FRAG_MSK __constant_cpu_to_le32(1 << 14)
-/* calculate TSF in outgoing frame */
+/* 1: uCode calculates and inserts Timestamp Function (TSF) in outgoing frame.
+ * 0: No TSF required in outgoing frame.
+ * Set this for transmitting beacons and probe responses. */
#define TX_CMD_FLG_TSF_MSK __constant_cpu_to_le32(1 << 16)
-/* activate TX calibration. */
-#define TX_CMD_FLG_CALIB_MSK __constant_cpu_to_le32(1 << 17)
-
-/* signals that 2 bytes pad was inserted
- after the MAC header */
+/* 1: Driver inserted 2 bytes pad after the MAC header, for (required) dword
+ * alignment of frame's payload data field.
+ * 0: No pad
+ * Set this for MAC headers with 26 or 30 bytes, i.e. those with QOS or ADDR4
+ * field (but not both). Driver must align frame data (i.e. data following
+ * MAC header) to DWORD boundary. */
#define TX_CMD_FLG_MH_PAD_MSK __constant_cpu_to_le32(1 << 20)
/* HCCA-AP - disable duration overwriting. */
#define TX_CMD_FLG_DUR_MSK __constant_cpu_to_le32(1 << 25)
+
/*
* TX command security control
*/
@@ -998,12 +1053,13 @@
#define TX_CMD_SEC_KEY128 0x08
/*
- * TX command Frame life time
+ * 4965 uCode updates these Tx attempt count values in host DRAM.
+ * Used for managing Tx retries when expecting block-acks.
+ * Driver should set these fields to 0.
*/
-
struct iwl4965_dram_scratch {
- u8 try_cnt;
- u8 bt_kill_cnt;
+ u8 try_cnt; /* Tx attempts */
+ u8 bt_kill_cnt; /* Tx attempts blocked by Bluetooth device */
__le16 reserved;
} __attribute__ ((packed));
@@ -1011,13 +1067,47 @@
* REPLY_TX = 0x1c (command)
*/
struct iwl4965_tx_cmd {
+ /*
+ * MPDU byte count:
+ * MAC header (24/26/30/32 bytes) + 2 bytes pad if 26/30 header size,
+ * + 8 byte IV for CCM or TKIP (not used for WEP)
+ * + Data payload
+ * + 8-byte MIC (not used for CCM/WEP)
+ * NOTE: Does not include Tx command bytes, post-MAC pad bytes,
+ * MIC (CCM) 8 bytes, ICV (WEP/TKIP/CKIP) 4 bytes, CRC 4 bytes.i
+ * Range: 14-2342 bytes.
+ */
__le16 len;
+
+ /*
+ * MPDU or MSDU byte count for next frame.
+ * Used for fragmentation and bursting, but not 11n aggregation.
+ * Same as "len", but for next frame. Set to 0 if not applicable.
+ */
__le16 next_frame_len;
- __le32 tx_flags;
+
+ __le32 tx_flags; /* TX_CMD_FLG_* */
+
+ /* 4965's uCode may modify this field of the Tx command (in host DRAM!).
+ * Driver must also set dram_lsb_ptr and dram_msb_ptr in this cmd. */
struct iwl4965_dram_scratch scratch;
- __le32 rate_n_flags;
+
+ /* Rate for *all* Tx attempts, if TX_CMD_FLG_STA_RATE_MSK is cleared. */
+ __le32 rate_n_flags; /* RATE_MCS_* */
+
+ /* Index of destination station in uCode's station table */
u8 sta_id;
- u8 sec_ctl;
+
+ /* Type of security encryption: CCM or TKIP */
+ u8 sec_ctl; /* TX_CMD_SEC_* */
+
+ /*
+ * Index into rate table (see REPLY_TX_LINK_QUALITY_CMD) for initial
+ * Tx attempt, if TX_CMD_FLG_STA_RATE_MSK is set. Normally "0" for
+ * data frames, this field may be used to selectively reduce initial
+ * rate (via non-0 value) for special frames (e.g. management), while
+ * still supporting rate scaling for all frames.
+ */
u8 initial_rate_index;
u8 reserved;
u8 key[16];
@@ -1027,8 +1117,12 @@
__le32 life_time;
__le32 attempt;
} stop_time;
+
+ /* Host DRAM physical address pointer to "scratch" in this command.
+ * Must be dword aligned. "0" in dram_lsb_ptr disables usage. */
__le32 dram_lsb_ptr;
u8 dram_msb_ptr;
+
u8 rts_retry_limit; /*byte 50 */
u8 data_retry_limit; /*byte 51 */
u8 tid_tspec;
@@ -1036,7 +1130,17 @@
__le16 pm_frame_timeout;
__le16 attempt_duration;
} timeout;
+
+ /*
+ * Duration of EDCA burst Tx Opportunity, in 32-usec units.
+ * Set this if txop time is not specified by HCCA protocol (e.g. by AP).
+ */
__le16 driver_txop;
+
+ /*
+ * MAC header goes here, followed by 2 bytes padding if MAC header
+ * length is 26 or 30 bytes, followed by payload data
+ */
u8 payload[0];
struct ieee80211_hdr hdr[0];
} __attribute__ ((packed));
@@ -1109,7 +1213,7 @@
};
/* *******************************
- * TX aggregation state
+ * TX aggregation status
******************************* */
enum {
@@ -1133,35 +1237,80 @@
AGG_TX_STATE_LAST_SENT_TRY_CNT_MSK | \
AGG_TX_STATE_LAST_SENT_BT_KILL_MSK)
+/* # tx attempts for first frame in aggregation */
#define AGG_TX_STATE_TRY_CNT_POS 12
#define AGG_TX_STATE_TRY_CNT_MSK 0xf000
+/* Command ID and sequence number of Tx command for this frame */
#define AGG_TX_STATE_SEQ_NUM_POS 16
#define AGG_TX_STATE_SEQ_NUM_MSK 0xffff0000
/*
* REPLY_TX = 0x1c (response)
+ *
+ * This response may be in one of two slightly different formats, indicated
+ * by the frame_count field:
+ *
+ * 1) No aggregation (frame_count == 1). This reports Tx results for
+ * a single frame. Multiple attempts, at various bit rates, may have
+ * been made for this frame.
+ *
+ * 2) Aggregation (frame_count > 1). This reports Tx results for
+ * 2 or more frames that used block-acknowledge. All frames were
+ * transmitted at same rate. Rate scaling may have been used if first
+ * frame in this new agg block failed in previous agg block(s).
+ *
+ * Note that, for aggregation, ACK (block-ack) status is not delivered here;
+ * block-ack has not been received by the time the 4965 records this status.
+ * This status relates to reasons the tx might have been blocked or aborted
+ * within the sending station (this 4965), rather than whether it was
+ * received successfully by the destination station.
*/
struct iwl4965_tx_resp {
u8 frame_count; /* 1 no aggregation, >1 aggregation */
- u8 bt_kill_count;
- u8 failure_rts;
- u8 failure_frame;
- __le32 rate_n_flags;
- __le16 wireless_media_time;
+ u8 bt_kill_count; /* # blocked by bluetooth (unused for agg) */
+ u8 failure_rts; /* # failures due to unsuccessful RTS */
+ u8 failure_frame; /* # failures due to no ACK (unused for agg) */
+
+ /* For non-agg: Rate at which frame was successful.
+ * For agg: Rate at which all frames were transmitted. */
+ __le32 rate_n_flags; /* RATE_MCS_* */
+
+ /* For non-agg: RTS + CTS + frame tx attempts time + ACK.
+ * For agg: RTS + CTS + aggregation tx time + block-ack time. */
+ __le16 wireless_media_time; /* uSecs */
+
__le16 reserved;
- __le32 pa_power1;
+ __le32 pa_power1; /* RF power amplifier measurement (not used) */
__le32 pa_power2;
+
+ /*
+ * For non-agg: frame status TX_STATUS_*
+ * For agg: status of 1st frame, AGG_TX_STATE_*; other frame status
+ * fields follow this one, up to frame_count.
+ * Bit fields:
+ * 11- 0: AGG_TX_STATE_* status code
+ * 15-12: Retry count for 1st frame in aggregation (retries
+ * occur if tx failed for this frame when it was a
+ * member of a previous aggregation block). If rate
+ * scaling is used, retry count indicates the rate
+ * table entry used for all frames in the new agg.
+ * 31-16: Sequence # for this frame's Tx cmd (not SSN!)
+ */
__le32 status; /* TX status (for aggregation status of 1st frame) */
} __attribute__ ((packed));
/*
* REPLY_COMPRESSED_BA = 0xc5 (response only, not a command)
+ *
+ * Reports Block-Acknowledge from recipient station
*/
struct iwl4965_compressed_ba_resp {
__le32 sta_addr_lo32;
__le16 sta_addr_hi16;
__le16 reserved;
+
+ /* Index of recipient (BA-sending) station in uCode's station table */
u8 sta_id;
u8 tid;
__le16 ba_seq_ctl;