diff options
author | Cahill, Ben M <ben.m.cahill@intel.com> | 2007-11-29 11:09:54 +0800 |
---|---|---|
committer | David S. Miller <davem@davemloft.net> | 2008-01-28 15:05:22 -0800 |
commit | 8b6eaea8ec79b111a18a1c60333deb16ba27e6b3 (patch) | |
tree | 4a6de834ae5c503e4140a763486ced7022dcb64d | |
parent | 74093ddf4c42da74922b63fb6844989e21164d9e (diff) |
iwlwifi: add comments, mostly on Tx queues
Add comments, mostly on Tx queues
Signed-off-by: Cahill, Ben M <ben.m.cahill@intel.com>
Signed-off-by: Zhu Yi <yi.zhu@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
-rw-r--r-- | drivers/net/wireless/iwlwifi/iwl-4965.c | 252 | ||||
-rw-r--r-- | drivers/net/wireless/iwlwifi/iwl4965-base.c | 18 |
2 files changed, 231 insertions, 39 deletions
diff --git a/drivers/net/wireless/iwlwifi/iwl-4965.c b/drivers/net/wireless/iwlwifi/iwl-4965.c index d44166a599f..40c795eaaba 100644 --- a/drivers/net/wireless/iwlwifi/iwl-4965.c +++ b/drivers/net/wireless/iwlwifi/iwl-4965.c @@ -144,7 +144,7 @@ int iwl4965_hw_rxq_stop(struct iwl4965_priv *priv) return rc; } - /* stop HW */ + /* stop Rx DMA */ iwl4965_write_direct32(priv, FH_MEM_RCSR_CHNL0_CONFIG_REG, 0); rc = iwl4965_poll_direct_bit(priv, FH_MEM_RSSR_RX_STATUS_REG, (1 << 24), 1000); @@ -234,17 +234,22 @@ static int iwl4965_rx_init(struct iwl4965_priv *priv, struct iwl4965_rx_queue *r return rc; } - /* stop HW */ + /* Stop Rx DMA */ iwl4965_write_direct32(priv, FH_MEM_RCSR_CHNL0_CONFIG_REG, 0); + /* Reset driver's Rx queue write index */ iwl4965_write_direct32(priv, FH_RSCSR_CHNL0_RBDCB_WPTR_REG, 0); + + /* Tell device where to find RBD circular buffer in DRAM */ iwl4965_write_direct32(priv, FH_RSCSR_CHNL0_RBDCB_BASE_REG, rxq->dma_addr >> 8); + /* Tell device where in DRAM to update its Rx status */ iwl4965_write_direct32(priv, FH_RSCSR_CHNL0_STTS_WPTR_REG, (priv->hw_setting.shared_phys + offsetof(struct iwl4965_shared, val0)) >> 4); + /* Enable Rx DMA, enable host interrupt, Rx buffer size 4k, 256 RBDs */ iwl4965_write_direct32(priv, FH_MEM_RCSR_CHNL0_CONFIG_REG, FH_RCSR_RX_CONFIG_CHNL_EN_ENABLE_VAL | FH_RCSR_CHNL0_RX_CONFIG_IRQ_DEST_INT_HOST_VAL | @@ -263,6 +268,7 @@ static int iwl4965_rx_init(struct iwl4965_priv *priv, struct iwl4965_rx_queue *r return 0; } +/* Tell 4965 where to find the "keep warm" buffer */ static int iwl4965_kw_init(struct iwl4965_priv *priv) { unsigned long flags; @@ -297,6 +303,11 @@ static int iwl4965_kw_alloc(struct iwl4965_priv *priv) #define CHECK_AND_PRINT(x) ((eeprom_ch->flags & EEPROM_CHANNEL_##x) \ ? # x " " : "") +/** + * iwl4965_set_fat_chan_info - Copy fat channel info into driver's priv. + * + * Does not set up a command, or touch hardware. + */ int iwl4965_set_fat_chan_info(struct iwl4965_priv *priv, int phymode, u16 channel, const struct iwl4965_eeprom_channel *eeprom_ch, u8 fat_extension_channel) @@ -337,6 +348,9 @@ int iwl4965_set_fat_chan_info(struct iwl4965_priv *priv, int phymode, u16 channe return 0; } +/** + * iwl4965_kw_free - Free the "keep warm" buffer + */ static void iwl4965_kw_free(struct iwl4965_priv *priv) { struct pci_dev *dev = priv->pci_dev; @@ -363,9 +377,10 @@ static int iwl4965_txq_ctx_reset(struct iwl4965_priv *priv) iwl4965_kw_free(priv); + /* Free all tx/cmd queues and keep-warm buffer */ iwl4965_hw_txq_ctx_free(priv); - /* Tx CMD queue */ + /* Alloc keep-warm buffer */ rc = iwl4965_kw_alloc(priv); if (rc) { IWL_ERROR("Keep Warm allocation failed"); @@ -381,17 +396,20 @@ static int iwl4965_txq_ctx_reset(struct iwl4965_priv *priv) goto error_reset; } + /* Turn off all Tx DMA channels */ iwl4965_write_prph(priv, KDR_SCD_TXFACT, 0); iwl4965_release_nic_access(priv); spin_unlock_irqrestore(&priv->lock, flags); + /* Tell 4965 where to find the keep-warm buffer */ rc = iwl4965_kw_init(priv); if (rc) { IWL_ERROR("kw_init failed\n"); goto error_reset; } - /* Tx queue(s) */ + /* Alloc and init all (default 16) Tx queues, + * including the command queue (#4) */ for (txq_id = 0; txq_id < priv->hw_setting.max_txq_num; txq_id++) { slots_num = (txq_id == IWL_CMD_QUEUE_NUM) ? TFD_CMD_SLOTS : TFD_TX_CMD_SLOTS; @@ -545,6 +563,8 @@ int iwl4965_hw_nic_init(struct iwl4965_priv *priv) iwl4965_rx_queue_update_write_ptr(priv, rxq); spin_unlock_irqrestore(&priv->lock, flags); + + /* Allocate and init all Tx and Command queues */ rc = iwl4965_txq_ctx_reset(priv); if (rc) return rc; @@ -593,13 +613,16 @@ int iwl4965_hw_nic_stop_master(struct iwl4965_priv *priv) return rc; } +/** + * iwl4965_hw_txq_ctx_stop - Stop all Tx DMA channels, free Tx queue memory + */ void iwl4965_hw_txq_ctx_stop(struct iwl4965_priv *priv) { int txq_id; unsigned long flags; - /* reset TFD queues */ + /* Stop each Tx DMA channel, and wait for it to be idle */ for (txq_id = 0; txq_id < priv->hw_setting.max_txq_num; txq_id++) { spin_lock_irqsave(&priv->lock, flags); if (iwl4965_grab_nic_access(priv)) { @@ -617,6 +640,7 @@ void iwl4965_hw_txq_ctx_stop(struct iwl4965_priv *priv) spin_unlock_irqrestore(&priv->lock, flags); } + /* Deallocate memory for all Tx queues */ iwl4965_hw_txq_ctx_free(priv); } @@ -1586,16 +1610,23 @@ static void iwl4965_set_wr_ptrs(struct iwl4965_priv *priv, int txq_id, u32 index iwl4965_write_prph(priv, KDR_SCD_QUEUE_RDPTR(txq_id), index); } -/* - * Acquire priv->lock before calling this function ! +/** + * iwl4965_tx_queue_set_status - (optionally) start Tx/Cmd queue + * @tx_fifo_id: Tx DMA/FIFO channel (range 0-7) that the queue will feed + * @scd_retry: (1) Indicates queue will be used in aggregation mode + * + * NOTE: Acquire priv->lock before calling this function ! */ static void iwl4965_tx_queue_set_status(struct iwl4965_priv *priv, struct iwl4965_tx_queue *txq, int tx_fifo_id, int scd_retry) { int txq_id = txq->q.id; + + /* Find out whether to activate Tx queue */ int active = test_bit(txq_id, &priv->txq_ctx_active_msk)?1:0; + /* Set up and activate */ iwl4965_write_prph(priv, KDR_SCD_QUEUE_STATUS_BITS(txq_id), (active << SCD_QUEUE_STTS_REG_POS_ACTIVE) | (tx_fifo_id << SCD_QUEUE_STTS_REG_POS_TXF) | @@ -1606,7 +1637,7 @@ static void iwl4965_tx_queue_set_status(struct iwl4965_priv *priv, txq->sched_retry = scd_retry; IWL_DEBUG_INFO("%s %s Queue %d on AC %d\n", - active ? "Activete" : "Deactivate", + active ? "Activate" : "Deactivate", scd_retry ? "BA" : "AC", txq_id, tx_fifo_id); } @@ -1654,6 +1685,7 @@ int iwl4965_alive_notify(struct iwl4965_priv *priv) return rc; } + /* Clear 4965's internal Tx Scheduler data base */ priv->scd_base_addr = iwl4965_read_prph(priv, KDR_SCD_SRAM_BASE_ADDR); a = priv->scd_base_addr + SCD_CONTEXT_DATA_OFFSET; for (; a < priv->scd_base_addr + SCD_TX_STTS_BITMAP_OFFSET; a += 4) @@ -1663,20 +1695,29 @@ int iwl4965_alive_notify(struct iwl4965_priv *priv) for (; a < sizeof(u16) * priv->hw_setting.max_txq_num; a += 4) iwl4965_write_targ_mem(priv, a, 0); + /* Tel 4965 where to find Tx byte count tables */ iwl4965_write_prph(priv, KDR_SCD_DRAM_BASE_ADDR, (priv->hw_setting.shared_phys + offsetof(struct iwl4965_shared, queues_byte_cnt_tbls)) >> 10); + + /* Disable chain mode for all queues */ iwl4965_write_prph(priv, KDR_SCD_QUEUECHAIN_SEL, 0); - /* initiate the queues */ + /* Initialize each Tx queue (including the command queue) */ for (i = 0; i < priv->hw_setting.max_txq_num; i++) { + + /* TFD circular buffer read/write indexes */ iwl4965_write_prph(priv, KDR_SCD_QUEUE_RDPTR(i), 0); iwl4965_write_direct32(priv, HBUS_TARG_WRPTR, 0 | (i << 8)); + + /* Max Tx Window size for Scheduler-ACK mode */ iwl4965_write_targ_mem(priv, priv->scd_base_addr + SCD_CONTEXT_QUEUE_OFFSET(i), (SCD_WIN_SIZE << SCD_QUEUE_CTX_REG1_WIN_SIZE_POS) & SCD_QUEUE_CTX_REG1_WIN_SIZE_MSK); + + /* Frame limit */ iwl4965_write_targ_mem(priv, priv->scd_base_addr + SCD_CONTEXT_QUEUE_OFFSET(i) + sizeof(u32), @@ -1688,11 +1729,13 @@ int iwl4965_alive_notify(struct iwl4965_priv *priv) iwl4965_write_prph(priv, KDR_SCD_INTERRUPT_MASK, (1 << priv->hw_setting.max_txq_num) - 1); + /* Activate all Tx DMA/FIFO channels */ iwl4965_write_prph(priv, KDR_SCD_TXFACT, SCD_TXFACT_REG_TXFIFO_MASK(0, 7)); iwl4965_set_wr_ptrs(priv, IWL_CMD_QUEUE_NUM, 0); - /* map qos queues to fifos one-to-one */ + + /* Map each Tx/cmd queue to its corresponding fifo */ for (i = 0; i < ARRAY_SIZE(default_queue_to_tx_fifo); i++) { int ac = default_queue_to_tx_fifo[i]; iwl4965_txq_ctx_activate(priv, i); @@ -1705,8 +1748,14 @@ int iwl4965_alive_notify(struct iwl4965_priv *priv) return 0; } +/** + * iwl4965_hw_set_hw_setting + * + * Called when initializing driver + */ int iwl4965_hw_set_hw_setting(struct iwl4965_priv *priv) { + /* Allocate area for Tx byte count tables and Rx queue status */ priv->hw_setting.shared_virt = pci_alloc_consistent(priv->pci_dev, sizeof(struct iwl4965_shared), @@ -1741,13 +1790,15 @@ void iwl4965_hw_txq_ctx_free(struct iwl4965_priv *priv) for (txq_id = 0; txq_id < priv->hw_setting.max_txq_num; txq_id++) iwl4965_tx_queue_free(priv, &priv->txq[txq_id]); + /* Keep-warm buffer */ iwl4965_kw_free(priv); } /** - * iwl4965_hw_txq_free_tfd - Free one TFD, those at index [txq->q.read_ptr] + * iwl4965_hw_txq_free_tfd - Free all chunks referenced by TFD [txq->q.read_ptr] * - * Does NOT advance any indexes + * Does NOT advance any TFD circular buffer read/write indexes + * Does NOT free the TFD itself (which is within circular buffer) */ int iwl4965_hw_txq_free_tfd(struct iwl4965_priv *priv, struct iwl4965_tx_queue *txq) { @@ -1758,12 +1809,11 @@ int iwl4965_hw_txq_free_tfd(struct iwl4965_priv *priv, struct iwl4965_tx_queue * int counter = 0; int index, is_odd; - /* classify bd */ + /* Host command buffers stay mapped in memory, nothing to clean */ if (txq->q.id == IWL_CMD_QUEUE_NUM) - /* nothing to cleanup after for host commands */ return 0; - /* sanity check */ + /* Sanity check on number of chunks */ counter = IWL_GET_BITS(*bd, num_tbs); if (counter > MAX_NUM_OF_TBS) { IWL_ERROR("Too many chunks: %i\n", counter); @@ -1771,8 +1821,8 @@ int iwl4965_hw_txq_free_tfd(struct iwl4965_priv *priv, struct iwl4965_tx_queue * return 0; } - /* unmap chunks if any */ - + /* Unmap chunks, if any. + * TFD info for odd chunks is different format than for even chunks. */ for (i = 0; i < counter; i++) { index = i / 2; is_odd = i & 0x1; @@ -1792,6 +1842,7 @@ int iwl4965_hw_txq_free_tfd(struct iwl4965_priv *priv, struct iwl4965_tx_queue * IWL_GET_BITS(bd->pa[index], tb1_len), PCI_DMA_TODEVICE); + /* Free SKB, if any, for this chunk */ if (txq->txb[txq->q.read_ptr].skb[i]) { struct sk_buff *skb = txq->txb[txq->q.read_ptr].skb[i]; @@ -1826,6 +1877,17 @@ static s32 iwl4965_math_div_round(s32 num, s32 denom, s32 *res) return 1; } +/** + * iwl4965_get_voltage_compensation - Power supply voltage comp for txpower + * + * Determines power supply voltage compensation for txpower calculations. + * Returns number of 1/2-dB steps to subtract from gain table index, + * to compensate for difference between power supply voltage during + * factory measurements, vs. current power supply voltage. + * + * Voltage indication is higher for lower voltage. + * Lower voltage requires more gain (lower gain table index). + */ static s32 iwl4965_get_voltage_compensation(s32 eeprom_voltage, s32 current_voltage) { @@ -1913,6 +1975,14 @@ static s32 iwl4965_interpolate_value(s32 x, s32 x1, s32 y1, s32 x2, s32 y2) } } +/** + * iwl4965_interpolate_chan - Interpolate factory measurements for one channel + * + * Interpolates factory measurements from the two sample channels within a + * sub-band, to apply to channel of interest. Interpolation is proportional to + * differences in channel frequencies, which is proportional to differences + * in channel number. + */ static int iwl4965_interpolate_chan(struct iwl4965_priv *priv, u32 channel, struct iwl4965_eeprom_calib_ch_info *chan_info) { @@ -2681,6 +2751,13 @@ unsigned int iwl4965_hw_get_beacon_cmd(struct iwl4965_priv *priv, return (sizeof(*tx_beacon_cmd) + frame_size); } +/* + * Tell 4965 where to find circular buffer of Tx Frame Descriptors for + * given Tx queue, and enable the DMA channel used for that queue. + * + * 4965 supports up to 16 Tx queues in DRAM, mapped to up to 8 Tx DMA + * channels supported in hardware. + */ int iwl4965_hw_tx_queue_init(struct iwl4965_priv *priv, struct iwl4965_tx_queue *txq) { int rc; @@ -2694,8 +2771,11 @@ int iwl4965_hw_tx_queue_init(struct iwl4965_priv *priv, struct iwl4965_tx_queue return rc; } + /* Circular buffer (TFD queue in DRAM) physical base address */ iwl4965_write_direct32(priv, FH_MEM_CBBC_QUEUE(txq_id), txq->q.dma_addr >> 8); + + /* Enable DMA channel, using same id as for TFD queue */ iwl4965_write_direct32( priv, IWL_FH_TCSR_CHNL_TX_CONFIG_REG(txq_id), IWL_FH_TCSR_TX_CONFIG_REG_VAL_DMA_CHNL_ENABLE | @@ -2718,6 +2798,7 @@ int iwl4965_hw_txq_attach_buf_to_tfd(struct iwl4965_priv *priv, void *ptr, struct iwl4965_tfd_frame *tfd = ptr; u32 num_tbs = IWL_GET_BITS(*tfd, num_tbs); + /* Each TFD can point to a maximum 20 Tx buffers */ if ((num_tbs >= MAX_NUM_OF_TBS) || (num_tbs < 0)) { IWL_ERROR("Error can not send more than %d chunks\n", MAX_NUM_OF_TBS); @@ -2759,6 +2840,9 @@ static void iwl4965_hw_card_show_info(struct iwl4965_priv *priv) #define IWL_TX_CRC_SIZE 4 #define IWL_TX_DELIMITER_SIZE 4 +/** + * iwl4965_tx_queue_update_wr_ptr - Set up entry in Tx byte-count array + */ int iwl4965_tx_queue_update_wr_ptr(struct iwl4965_priv *priv, struct iwl4965_tx_queue *txq, u16 byte_cnt) { @@ -2771,9 +2855,11 @@ int iwl4965_tx_queue_update_wr_ptr(struct iwl4965_priv *priv, len = byte_cnt + IWL_TX_CRC_SIZE + IWL_TX_DELIMITER_SIZE; + /* Set up byte count within first 256 entries */ IWL_SET_BITS16(shared_data->queues_byte_cnt_tbls[txq_id]. tfd_offset[txq->q.write_ptr], byte_cnt, len); + /* If within first 64 entries, duplicate at end */ if (txq->q.write_ptr < IWL4965_MAX_WIN_SIZE) IWL_SET_BITS16(shared_data->queues_byte_cnt_tbls[txq_id]. tfd_offset[IWL4965_QUEUE_SIZE + txq->q.write_ptr], @@ -2782,8 +2868,12 @@ int iwl4965_tx_queue_update_wr_ptr(struct iwl4965_priv *priv, return 0; } -/* Set up Rx receiver/antenna/chain usage in "staging" RXON image. - * This should not be used for scan command ... it puts data in wrong place. */ +/** + * iwl4965_set_rxon_chain - Set up Rx chain usage in "staging" RXON image + * + * Selects how many and which Rx receivers/antennas/chains to use. + * This should not be used for scan command ... it puts data in wrong place. + */ void iwl4965_set_rxon_chain(struct iwl4965_priv *priv) { u8 is_single = is_single_stream(priv); @@ -2931,6 +3021,9 @@ enum HT_STATUS { BA_STATUS_ACTIVE, }; +/** + * iwl4964_tl_ba_avail - Find out if an unused aggregation queue is available + */ static u8 iwl4964_tl_ba_avail(struct iwl4965_priv *priv) { int i; @@ -2939,6 +3032,8 @@ static u8 iwl4964_tl_ba_avail(struct iwl4965_priv *priv) u16 msk; lq = (struct iwl4965_lq_mngr *)&(priv->lq_mngr); + + /* Find out how many agg queues are in use */ for (i = 0; i < TID_MAX_LOAD_COUNT ; i++) { msk = 1 << i; if ((lq->agg_ctrl.granted_ba & msk) || @@ -3080,6 +3175,9 @@ void iwl4965_turn_off_agg(struct iwl4965_priv *priv, u8 tid) } } +/** + * iwl4965_ba_status - Update driver's link quality mgr with tid's HT status + */ static void iwl4965_ba_status(struct iwl4965_priv *priv, u8 tid, enum HT_STATUS status) { @@ -3301,11 +3399,12 @@ int iwl4965_get_temperature(const struct iwl4965_priv *priv) } /* - * Temperature is only 23 bits so sign extend out to 32 + * Temperature is only 23 bits, so sign extend out to 32. * * NOTE If we haven't received a statistics notification yet * with an updated temperature, use R4 provided to us in the - * ALIVE response. */ + * "initialize" ALIVE response. + */ if (!test_bit(STATUS_TEMPERATURE, &priv->status)) vt = sign_extend(R4, 23); else @@ -4001,6 +4100,11 @@ static void iwl4965_rx_missed_beacon_notif(struct iwl4965_priv *priv, #ifdef CONFIG_IWL4965_HT #ifdef CONFIG_IWL4965_HT_AGG +/** + * iwl4965_set_tx_status - Update driver's record of one Tx frame's status + * + * This will get sent to mac80211. + */ static void iwl4965_set_tx_status(struct iwl4965_priv *priv, int txq_id, int idx, u32 status, u32 retry_count, u32 rate) { @@ -4013,11 +4117,15 @@ static void iwl4965_set_tx_status(struct iwl4965_priv *priv, int txq_id, int idx } +/** + * iwl4965_sta_modify_enable_tid_tx - Enable Tx for this TID in station table + */ static void iwl4965_sta_modify_enable_tid_tx(struct iwl4965_priv *priv, int sta_id, int tid) { unsigned long flags; + /* Remove "disable" flag, to enable Tx for this TID */ spin_lock_irqsave(&priv->sta_lock, flags); priv->stations[sta_id].sta.sta.modify_mask = STA_MODIFY_TID_DISABLE_TX; priv->stations[sta_id].sta.tid_disable_tx &= cpu_to_le16(~(1 << tid)); @@ -4028,6 +4136,12 @@ static void iwl4965_sta_modify_enable_tid_tx(struct iwl4965_priv *priv, } +/** + * iwl4965_tx_status_reply_compressed_ba - Update tx status from block-ack + * + * Go through block-ack's bitmap of ACK'd frames, update driver's record of + * ACK vs. not. This gets sent to mac80211, then to rate scaling algo. + */ static int iwl4965_tx_status_reply_compressed_ba(struct iwl4965_priv *priv, struct iwl4965_ht_agg *agg, struct iwl4965_compressed_ba_resp* @@ -4044,13 +4158,17 @@ static int iwl4965_tx_status_reply_compressed_ba(struct iwl4965_priv *priv, IWL_ERROR("Received BA when not expected\n"); return -EINVAL; } + + /* Mark that the expected block-ack response arrived */ agg->wait_for_ba = 0; IWL_DEBUG_TX_REPLY("BA %d %d\n", agg->start_idx, ba_resp->ba_seq_ctl); + + /* Calculate shift to align block-ack bits with our Tx window bits */ sh = agg->start_idx - SEQ_TO_INDEX(ba_seq_ctl>>4); if (sh < 0) /* tbw something is wrong with indices */ sh += 0x100; - /* don't use 64 bits for now */ + /* don't use 64-bit values for now */ bitmap0 = resp_bitmap0 >> sh; bitmap1 = resp_bitmap1 >> sh; bitmap0 |= (resp_bitmap1 & ((1<<sh)|((1<<sh)-1))) << (32 - sh); @@ -4061,10 +4179,12 @@ static int iwl4965_tx_status_reply_compressed_ba(struct iwl4965_priv *priv, } /* check for success or failure according to the - * transmitted bitmap and back bitmap */ + * transmitted bitmap and block-ack bitmap */ bitmap0 &= agg->bitmap0; bitmap1 &= agg->bitmap1; + /* For each frame attempted in aggregation, + * update driver's record of tx frame's status. */ for (i = 0; i < agg->frame_count ; i++) { int idx = (agg->start_idx + i) & 0xff; ack = bitmap0 & (1 << i); @@ -4080,11 +4200,22 @@ static int iwl4965_tx_status_reply_compressed_ba(struct iwl4965_priv *priv, return 0; } +/** + * iwl4965_queue_dec_wrap - Decrement queue index, wrap back to end if needed + * @index -- current index + * @n_bd -- total number of entries in queue (s/b power of 2) + */ static inline int iwl4965_queue_dec_wrap(int index, int n_bd) { return (index == 0) ? n_bd - 1 : index - 1; } +/** + * iwl4965_rx_reply_compressed_ba - Handler for REPLY_COMPRESSED_BA + * + * Handles block-acknowledge notification from device, which reports success + * of frames sent via aggregation. + */ static void iwl4965_rx_reply_compressed_ba(struct iwl4965_priv *priv, struct iwl4965_rx_mem_buffer *rxb) { @@ -4093,7 +4224,12 @@ static void iwl4965_rx_reply_compressed_ba(struct iwl4965_priv *priv, int index; struct iwl4965_tx_queue *txq = NULL; struct iwl4965_ht_agg *agg; + + /* "flow" corresponds to Tx queue */ u16 ba_resp_scd_flow = le16_to_cpu(ba_resp->scd_flow); + + /* "ssn" is start of block-ack Tx window, corresponds to index + * (in Tx queue's circular buffer) of first TFD/frame in window */ u16 ba_resp_scd_ssn = le16_to_cpu(ba_resp->scd_ssn); if (ba_resp_scd_flow >= ARRAY_SIZE(priv->txq)) { @@ -4103,6 +4239,8 @@ static void iwl4965_rx_reply_compressed_ba(struct iwl4965_priv *priv, txq = &priv->txq[ba_resp_scd_flow]; agg = &priv->stations[ba_resp->sta_id].tid[ba_resp->tid].agg; + + /* Find index just before block-ack window */ index = iwl4965_queue_dec_wrap(ba_resp_scd_ssn & 0xff, txq->q.n_bd); /* TODO: Need to get this copy more safely - now good for debug */ @@ -4128,22 +4266,35 @@ static void iwl4965_rx_reply_compressed_ba(struct iwl4965_priv *priv, agg->bitmap0); } */ + + /* Update driver's record of ACK vs. not for each frame in window */ iwl4965_tx_status_reply_compressed_ba(priv, agg, ba_resp); - /* releases all the TFDs until the SSN */ + + /* Release all TFDs before the SSN, i.e. all TFDs in front of + * block-ack window (we assume that they've been successfully + * transmitted ... if not, it's too late anyway). */ if (txq->q.read_ptr != (ba_resp_scd_ssn & 0xff)) iwl4965_tx_queue_reclaim(priv, ba_resp_scd_flow, index); } +/** + * iwl4965_tx_queue_stop_scheduler - Stop queue, but keep configuration + */ static void iwl4965_tx_queue_stop_scheduler(struct iwl4965_priv *priv, u16 txq_id) { + /* Simply stop the queue, but don't change any configuration; + * the SCD_ACT_EN bit is the write-enable mask for the ACTIVE bit. */ iwl4965_write_prph(priv, KDR_SCD_QUEUE_STATUS_BITS(txq_id), (0 << SCD_QUEUE_STTS_REG_POS_ACTIVE)| (1 << SCD_QUEUE_STTS_REG_POS_SCD_ACT_EN)); } +/** + * iwl4965_tx_queue_set_q2ratid - Map unique receiver/tid combination to a queue + */ static int iwl4965_tx_queue_set_q2ratid(struct iwl4965_priv *priv, u16 ra_tid, u16 txq_id) { @@ -4169,7 +4320,10 @@ static int iwl4965_tx_queue_set_q2ratid(struct iwl4965_priv *priv, u16 ra_tid, } /** - * txq_id must be greater than IWL_BACK_QUEUE_FIRST_ID + * iwl4965_tx_queue_agg_enable - Set up & enable aggregation for selected queue + * + * NOTE: txq_id must be greater than IWL_BACK_QUEUE_FIRST_ID, + * i.e. it must be one of the higher queues used for aggregation */ static int iwl4965_tx_queue_agg_enable(struct iwl4965_priv *priv, int txq_id, int tx_fifo, int sta_id, int tid, @@ -4185,6 +4339,7 @@ static int iwl4965_tx_queue_agg_enable(struct iwl4965_priv *priv, int txq_id, ra_tid = BUILD_RAxTID(sta_id, tid); + /* Modify device's station table to Tx this TID */ iwl4965_sta_modify_enable_tid_tx(priv, sta_id, tid); spin_lock_irqsave(&priv->lock, flags); @@ -4194,19 +4349,22 @@ static int iwl4965_tx_queue_agg_enable(struct iwl4965_priv *priv, int txq_id, return rc; } + /* Stop this Tx queue before configuring it */ iwl4965_tx_queue_stop_scheduler(priv, txq_id); + /* Map receiver-address / traffic-ID to this queue */ iwl4965_tx_queue_set_q2ratid(priv, ra_tid, txq_id); - + /* Set this queue as a chain-building queue */ iwl4965_set_bits_prph(priv, KDR_SCD_QUEUECHAIN_SEL, (1<<txq_id)); + /* Place first TFD at index corresponding to start sequence number. + * Assumes that ssn_idx is valid (!= 0xFFF) */ priv->txq[txq_id].q.read_ptr = (ssn_idx & 0xff); priv->txq[txq_id].q.write_ptr = (ssn_idx & 0xff); - - /* supposes that ssn_idx is valid (!= 0xFFF) */ iwl4965_set_wr_ptrs(priv, txq_id, ssn_idx); + /* Set up Tx window size and frame limit for this queue */ iwl4965_write_targ_mem(priv, priv->scd_base_addr + SCD_CONTEXT_QUEUE_OFFSET(txq_id), (SCD_WIN_SIZE << SCD_QUEUE_CTX_REG1_WIN_SIZE_POS) & @@ -4219,6 +4377,7 @@ static int iwl4965_tx_queue_agg_enable(struct iwl4965_priv *priv, int txq_id, iwl4965_set_bits_prph(priv, KDR_SCD_INTERRUPT_MASK, (1 << txq_id)); + /* Set up Status area in SRAM, map to Tx DMA/FIFO, activate the queue */ iwl4965_tx_queue_set_status(priv, &priv->txq[txq_id], tx_fifo, 1); iwl4965_release_nic_access(priv); @@ -4274,14 +4433,16 @@ static int iwl4965_tx_queue_agg_disable(struct iwl4965_priv *priv, u16 txq_id, /** * iwl4965_add_station - Initialize a station's hardware rate table * - * The uCode contains a table of fallback rates and retries per rate + * The uCode's station table contains a table of fallback rates * for automatic fallback during transmission. * - * NOTE: This initializes the table for a single retry per data rate - * which is not optimal. Setting up an intelligent retry per rate - * requires feedback from transmission, which isn't exposed through - * rc80211_simple which is what this driver is currently using. + * NOTE: This sets up a default set of values. These will be replaced later + * if the driver's iwl-4965-rs rate scaling algorithm is used, instead of + * rc80211_simple. * + * NOTE: Run REPLY_ADD_STA command to set up station table entry, before + * calling this function (which runs REPLY_TX_LINK_QUALITY_CMD, + * which requires station table entry to exist). */ void iwl4965_add_station(struct iwl4965_priv *priv, const u8 *addr, int is_ap) { @@ -4291,8 +4452,8 @@ void iwl4965_add_station(struct iwl4965_priv *priv, const u8 *addr, int is_ap) }; u16 rate_flags; - /* Set up the rate scaling to start at 54M and fallback - * all the way to 1M in IEEE order and then spin on IEEE */ + /* Set up the rate scaling to start at selected rate, fall back + * all the way down to 1M in IEEE order, and then spin on 1M */ if (is_ap) r = IWL_RATE_54M_INDEX; else if (priv->phymode == MODE_IEEE80211A) @@ -4305,8 +4466,10 @@ void iwl4965_add_station(struct iwl4965_priv *priv, const u8 *addr, int is_ap) if (r >= IWL_FIRST_CCK_RATE && r <= IWL_LAST_CCK_RATE) rate_flags |= RATE_MCS_CCK_MSK; + /* Use Tx antenna B only */ rate_flags |= RATE_MCS_ANT_B_MSK; rate_flags &= ~RATE_MCS_ANT_A_MSK; + link_cmd.rs_table[i].rate_n_flags = iwl4965_hw_set_rate_n_flags(iwl4965_rates[r].plcp, rate_flags); r = iwl4965_get_prev_ieee_rate(r); @@ -4374,6 +4537,7 @@ void iwl4965_set_rxon_ht(struct iwl4965_priv *priv, struct sta_ht_info *ht_info) if (!ht_info->is_ht) return; + /* Set up channel bandwidth: 20 MHz only, or 20/40 mixed if fat ok */ if (iwl4965_is_fat_tx_allowed(priv, ht_info)) rxon->flags |= RXON_FLG_CHANNEL_MODE_MIXED_MSK; else @@ -4388,7 +4552,7 @@ void iwl4965_set_rxon_ht(struct iwl4965_priv *priv, struct sta_ht_info *ht_info) return; } - /* Note: control channel is oposit to extension channel */ + /* Note: control channel is opposite of extension channel */ switch (ht_info->extension_chan_offset) { case IWL_EXT_CHANNEL_OFFSET_ABOVE: rxon->flags &= ~(RXON_FLG_CTRL_CHANNEL_LOC_HI_MSK); @@ -4514,6 +4678,12 @@ static const u16 default_tid_to_tx_fifo[] = { IWL_TX_FIFO_AC3 }; +/* + * Find first available (lowest unused) Tx Queue, mark it "active". + * Called only when finding queue for aggregation. + * Should never return anything < 7, because they should already + * be in use as EDCA AC (0-3), Command (4), HCCA (5, 6). + */ static int iwl4965_txq_ctx_activate_free(struct iwl4965_priv *priv) { int txq_id; @@ -4537,6 +4707,7 @@ int iwl4965_mac_ht_tx_agg_start(struct ieee80211_hw *hw, u8 *da, u16 tid, struct iwl4965_tid_data *tid_data; DECLARE_MAC_BUF(mac); + /* Determine Tx DMA/FIFO channel for this Traffic ID */ if (likely(tid < ARRAY_SIZE(default_tid_to_tx_fifo))) tx_fifo = default_tid_to_tx_fifo[tid]; else @@ -4545,22 +4716,31 @@ int iwl4965_mac_ht_tx_agg_start(struct ieee80211_hw *hw, u8 *da, u16 tid, IWL_WARNING("iwl-AGG iwl4965_mac_ht_tx_agg_start on da=%s" " tid=%d\n", print_mac(mac, da), tid); + /* Get index into station table */ sta_id = iwl4965_hw_find_station(priv, da); if (sta_id == IWL_INVALID_STATION) return -ENXIO; + /* Find available Tx queue for aggregation */ txq_id = iwl4965_txq_ctx_activate_free(priv); if (txq_id == -1) return -ENXIO; spin_lock_irqsave(&priv->sta_lock, flags); tid_data = &priv->stations[sta_id].tid[tid]; + + /* Get starting sequence number for 1st frame in block ack window. + * We'll use least signif byte as 1st frame's index into Tx queue. */ ssn = SEQ_TO_SN(tid_data->seq_number); tid_data->agg.txq_id = txq_id; spin_unlock_irqrestore(&priv->sta_lock, flags); *start_seq_num = ssn; + + /* Update driver's link quality manager */ iwl4965_ba_status(priv, tid, BA_STATUS_ACTIVE); + + /* Set up and enable aggregation for selected Tx queue and FIFO */ return iwl4965_tx_queue_agg_enable(priv, txq_id, tx_fifo, sta_id, tid, ssn); } diff --git a/drivers/net/wireless/iwlwifi/iwl4965-base.c b/drivers/net/wireless/iwlwifi/iwl4965-base.c index 74c3d3917fe..66aa938e316 100644 --- a/drivers/net/wireless/iwlwifi/iwl4965-base.c +++ b/drivers/net/wireless/iwlwifi/iwl4965-base.c @@ -305,6 +305,9 @@ static int iwl4965_tx_queue_alloc(struct iwl4965_priv *priv, return -ENOMEM; } +/** + * iwl4965_tx_queue_init - Allocate and initialize one tx/cmd queue + */ int iwl4965_tx_queue_init(struct iwl4965_priv *priv, struct iwl4965_tx_queue *txq, int slots_num, u32 txq_id) { @@ -312,9 +315,14 @@ int iwl4965_tx_queue_init(struct iwl4965_priv *priv, int len; int rc = 0; - /* allocate command space + one big command for scan since scan - * command is very huge the system will not have two scan at the - * same time */ + /* + * Alloc buffer array for commands (Tx or other types of commands). + * For the command queue (#4), allocate command space + one big + * command for scan, since scan command is very huge; the system will + * not have two scans at the same time, so only one is needed. + * For normal Tx queues (all other queues), no super-size command + * space is needed. + */ len = sizeof(struct iwl4965_cmd) * slots_num; if (txq_id == IWL_CMD_QUEUE_NUM) len += IWL_MAX_SCAN_SIZE; @@ -322,6 +330,7 @@ int iwl4965_tx_queue_init(struct iwl4965_priv *priv, if (!txq->cmd) return -ENOMEM; + /* Alloc driver data array and TFD circular buffer */ rc = iwl4965_tx_queue_alloc(priv, txq, txq_id); if (rc) { pci_free_consistent(dev, len, txq->cmd, txq->dma_addr_cmd); @@ -333,8 +342,11 @@ int iwl4965_tx_queue_init(struct iwl4965_priv *priv, /* TFD_QUEUE_SIZE_MAX must be power-of-two size, otherwise * iwl4965_queue_inc_wrap and iwl4965_queue_dec_wrap are broken. */ BUILD_BUG_ON(TFD_QUEUE_SIZE_MAX & (TFD_QUEUE_SIZE_MAX - 1)); + + /* Initialize queue's high/low-water marks, and head/tail indexes */ iwl4965_queue_init(priv, &txq->q, TFD_QUEUE_SIZE_MAX, slots_num, txq_id); + /* Tell device where to find queue */ iwl4965_hw_tx_queue_init(priv, txq); return 0; |