iwlagn: move Tx datapath to transport layer

Split the Tx datapath in two parts:
* the first deals with the Tx cmd composition
* the second attaches the skb + Tx cmd to the queues

Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>

5 files changed, 189 insertions, 146 deletions

diff --git a/drivers/net/wireless/iwlwifi/iwl-agn-tx.c b/drivers/net/wireless/iwlwifi/iwl-agn-tx.c
index 7d3aad83e0d..f306824157e 100644
--- a/drivers/net/wireless/iwlwifi/iwl-agn-tx.c
+++ b/drivers/net/wireless/iwlwifi/iwl-agn-tx.c
@@ -39,6 +39,7 @@
 #include "iwl-helpers.h"
 #include "iwl-agn-hw.h"
 #include "iwl-agn.h"
+#include "iwl-trans.h"
 
 /*
  * mac80211 queues, ACs, hardware queues, FIFOs.
@@ -98,7 +99,7 @@ static inline int get_fifo_from_tid(struct iwl_rxon_context *ctx, u16 tid)
 /**
  * iwlagn_txq_update_byte_cnt_tbl - Set up entry in Tx byte-count array
  */
-static void iwlagn_txq_update_byte_cnt_tbl(struct iwl_priv *priv,
+void iwlagn_txq_update_byte_cnt_tbl(struct iwl_priv *priv,
                                            struct iwl_tx_queue *txq,
                                            u16 byte_cnt)
 {
@@ -547,26 +548,17 @@ int iwlagn_tx_skb(struct iwl_priv *priv, struct sk_buff *skb)
 {
         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
-        struct ieee80211_sta *sta = info->control.sta;
         struct iwl_station_priv *sta_priv = NULL;
-        struct iwl_tx_queue *txq;
-        struct iwl_queue *q;
-        struct iwl_device_cmd *out_cmd;
-        struct iwl_cmd_meta *out_meta;
-        struct iwl_tx_cmd *tx_cmd;
         struct iwl_rxon_context *ctx = &priv->contexts[IWL_RXON_CTX_BSS];
+        struct iwl_tx_cmd *tx_cmd;
         int txq_id;
-        dma_addr_t phys_addr = 0;
-        dma_addr_t txcmd_phys;
-        dma_addr_t scratch_phys;
-        u16 len, firstlen, secondlen;
+
         u16 seq_number = 0;
         __le16 fc;
         u8 hdr_len;
+        u16 len;
         u8 sta_id;
-        u8 wait_write_ptr = 0;
         u8 tid = 0;
-        u8 *qc = NULL;
         unsigned long flags;
         bool is_agg = false;
 
@@ -614,8 +606,8 @@ int iwlagn_tx_skb(struct iwl_priv *priv, struct sk_buff *skb)
 
         IWL_DEBUG_TX(priv, "station Id %d\n", sta_id);
 
-        if (sta)
-                sta_priv = (void *)sta->drv_priv;
+        if (info->control.sta)
+                sta_priv = (void *)info->control.sta->drv_priv;
 
         if (sta_priv && sta_priv->asleep &&
             (info->flags & IEEE80211_TX_CTL_PSPOLL_RESPONSE)) {
@@ -650,6 +642,7 @@ int iwlagn_tx_skb(struct iwl_priv *priv, struct sk_buff *skb)
         spin_lock(&priv->sta_lock);
 
         if (ieee80211_is_data_qos(fc)) {
+                u8 *qc = NULL;
                 qc = ieee80211_get_qos_ctl(hdr);
                 tid = qc[0] & IEEE80211_QOS_CTL_TID_MASK;
 
@@ -670,38 +663,13 @@ int iwlagn_tx_skb(struct iwl_priv *priv, struct sk_buff *skb)
                 }
         }
 
-        txq = &priv->txq[txq_id];
-        q = &txq->q;
-
-        if (unlikely(iwl_queue_space(q) < q->high_mark))
+        tx_cmd = trans_get_tx_cmd(priv, txq_id);
+        if (unlikely(!tx_cmd))
                 goto drop_unlock_sta;
 
-        /* Set up driver data for this TFD */
-        memset(&(txq->txb[q->write_ptr]), 0, sizeof(struct iwl_tx_info));
-        txq->txb[q->write_ptr].skb = skb;
-        txq->txb[q->write_ptr].ctx = ctx;
-
-        /* Set up first empty entry in queue's array of Tx/cmd buffers */
-        out_cmd = txq->cmd[q->write_ptr];
-        out_meta = &txq->meta[q->write_ptr];
-        tx_cmd = &out_cmd->cmd.tx;
-        memset(&out_cmd->hdr, 0, sizeof(out_cmd->hdr));
-        memset(tx_cmd, 0, sizeof(struct iwl_tx_cmd));
-
-        /*
-         * Set up the Tx-command (not MAC!) header.
-         * Store the chosen Tx queue and TFD index within the sequence field;
-         * after Tx, uCode's Tx response will return this value so driver can
-         * locate the frame within the tx queue and do post-tx processing.
-         */
-        out_cmd->hdr.cmd = REPLY_TX;
-        out_cmd->hdr.sequence = cpu_to_le16((u16)(QUEUE_TO_SEQ(txq_id) |
-                                INDEX_TO_SEQ(q->write_ptr)));
-
         /* Copy MAC header from skb into command buffer */
         memcpy(tx_cmd->hdr, hdr, hdr_len);
 
-
         /* Total # bytes to be transmitted */
         len = (u16)skb->len;
         tx_cmd->len = cpu_to_le16(len);
@@ -716,54 +684,9 @@ int iwlagn_tx_skb(struct iwl_priv *priv, struct sk_buff *skb)
         iwlagn_tx_cmd_build_rate(priv, tx_cmd, info, fc);
 
         iwl_update_stats(priv, true, fc, len);
-        /*
-         * Use the first empty entry in this queue's command buffer array
-         * to contain the Tx command and MAC header concatenated together
-         * (payload data will be in another buffer).
-         * Size of this varies, due to varying MAC header length.
-         * If end is not dword aligned, we'll have 2 extra bytes at the end
-         * of the MAC header (device reads on dword boundaries).
-         * We'll tell device about this padding later.
-         */
-        len = sizeof(struct iwl_tx_cmd) +
-                sizeof(struct iwl_cmd_header) + hdr_len;
-        firstlen = (len + 3) & ~3;
-
-        /* Tell NIC about any 2-byte padding after MAC header */
-        if (firstlen != len)
-                tx_cmd->tx_flags |= TX_CMD_FLG_MH_PAD_MSK;
-
-        /* Physical address of this Tx command's header (not MAC header!),
-         * within command buffer array. */
-        txcmd_phys = dma_map_single(priv->bus.dev,
-                                    &out_cmd->hdr, firstlen,
-                                    DMA_BIDIRECTIONAL);
-        if (unlikely(dma_mapping_error(priv->bus.dev, txcmd_phys)))
-                goto drop_unlock_sta;
-        dma_unmap_addr_set(out_meta, mapping, txcmd_phys);
-        dma_unmap_len_set(out_meta, len, firstlen);
 
-        if (!ieee80211_has_morefrags(hdr->frame_control)) {
-                txq->need_update = 1;
-        } else {
-                wait_write_ptr = 1;
-                txq->need_update = 0;
-        }
-
-        /* Set up TFD's 2nd entry to point directly to remainder of skb,
-         * if any (802.11 null frames have no payload). */
-        secondlen = skb->len - hdr_len;
-        if (secondlen > 0) {
-                phys_addr = dma_map_single(priv->bus.dev, skb->data + hdr_len,
-                                           secondlen, DMA_TO_DEVICE);
-                if (unlikely(dma_mapping_error(priv->bus.dev, phys_addr))) {
-                        dma_unmap_single(priv->bus.dev,
-                                         dma_unmap_addr(out_meta, mapping),
-                                         dma_unmap_len(out_meta, len),
-                                         DMA_BIDIRECTIONAL);
-                        goto drop_unlock_sta;
-                }
-        }
+        if (trans_tx(priv, skb, tx_cmd, txq_id, fc, is_agg, ctx))
+                goto drop_unlock_sta;
 
         if (ieee80211_is_data_qos(fc)) {
                 priv->stations[sta_id].tid[tid].tfds_in_queue++;
@@ -772,55 +695,9 @@ int iwlagn_tx_skb(struct iwl_priv *priv, struct sk_buff *skb)
         }
 
         spin_unlock(&priv->sta_lock);
-
-        /* Attach buffers to TFD */
-        iwlagn_txq_attach_buf_to_tfd(priv, txq, txcmd_phys, firstlen, 1);
-        if (secondlen > 0)
-                iwlagn_txq_attach_buf_to_tfd(priv, txq, phys_addr,
-                                             secondlen, 0);
-
-        scratch_phys = txcmd_phys + sizeof(struct iwl_cmd_header) +
-                                offsetof(struct iwl_tx_cmd, scratch);
-
-        /* take back ownership of DMA buffer to enable update */
-        dma_sync_single_for_cpu(priv->bus.dev, txcmd_phys, firstlen,
-                        DMA_BIDIRECTIONAL);
-        tx_cmd->dram_lsb_ptr = cpu_to_le32(scratch_phys);
-        tx_cmd->dram_msb_ptr = iwl_get_dma_hi_addr(scratch_phys);
-
-        IWL_DEBUG_TX(priv, "sequence nr = 0X%x\n",
-                     le16_to_cpu(out_cmd->hdr.sequence));
-        IWL_DEBUG_TX(priv, "tx_flags = 0X%x\n", le32_to_cpu(tx_cmd->tx_flags));
-        iwl_print_hex_dump(priv, IWL_DL_TX, (u8 *)tx_cmd, sizeof(*tx_cmd));
-        iwl_print_hex_dump(priv, IWL_DL_TX, (u8 *)tx_cmd->hdr, hdr_len);
-
-        /* Set up entry for this TFD in Tx byte-count array */
-        if (info->flags & IEEE80211_TX_CTL_AMPDU)
-                iwlagn_txq_update_byte_cnt_tbl(priv, txq,
-                                               le16_to_cpu(tx_cmd->len));
-
-        dma_sync_single_for_device(priv->bus.dev, txcmd_phys, firstlen,
-                        DMA_BIDIRECTIONAL);
-
-        trace_iwlwifi_dev_tx(priv,
-                             &((struct iwl_tfd *)txq->tfds)[txq->q.write_ptr],
-                             sizeof(struct iwl_tfd),
-                             &out_cmd->hdr, firstlen,
-                             skb->data + hdr_len, secondlen);
-
-        /* Tell device the write index *just past* this latest filled TFD */
-        q->write_ptr = iwl_queue_inc_wrap(q->write_ptr, q->n_bd);
-        iwl_txq_update_write_ptr(priv, txq);
         spin_unlock_irqrestore(&priv->lock, flags);
 
         /*
-         * At this point the frame is "transmitted" successfully
-         * and we will get a TX status notification eventually,
-         * regardless of the value of ret. "ret" only indicates
-         * whether or not we should update the write pointer.
-         */
-
-        /*
          * Avoid atomic ops if it isn't an associated client.
          * Also, if this is a packet for aggregation, don't
          * increase the counter because the ucode will stop
@@ -830,17 +707,6 @@ int iwlagn_tx_skb(struct iwl_priv *priv, struct sk_buff *skb)
         if (sta_priv && sta_priv->client && !is_agg)
                 atomic_inc(&sta_priv->pending_frames);
 
-        if ((iwl_queue_space(q) < q->high_mark) && priv->mac80211_registered) {
-                if (wait_write_ptr) {
-                        spin_lock_irqsave(&priv->lock, flags);
-                        txq->need_update = 1;
-                        iwl_txq_update_write_ptr(priv, txq);
-                        spin_unlock_irqrestore(&priv->lock, flags);
-                } else {
-                        iwl_stop_queue(priv, txq);
-                }
-        }
-
         return 0;
 
 drop_unlock_sta:
diff --git a/drivers/net/wireless/iwlwifi/iwl-agn.h b/drivers/net/wireless/iwlwifi/iwl-agn.h
index 5f58b44bb2a..aed86c6cd93 100644
--- a/drivers/net/wireless/iwlwifi/iwl-agn.h
+++ b/drivers/net/wireless/iwlwifi/iwl-agn.h
@@ -142,6 +142,10 @@ void iwlagn_stop_device(struct iwl_priv *priv);
 /* tx queue */
 void iwlagn_set_wr_ptrs(struct iwl_priv *priv,
                      int txq_id, u32 index);
+void iwlagn_txq_update_byte_cnt_tbl(struct iwl_priv *priv,
+                                           struct iwl_tx_queue *txq,
+                                           u16 byte_cnt);
+
 void iwlagn_tx_queue_set_status(struct iwl_priv *priv,
                              struct iwl_tx_queue *txq,
                              int tx_fifo_id, int scd_retry);
diff --git a/drivers/net/wireless/iwlwifi/iwl-dev.h b/drivers/net/wireless/iwlwifi/iwl-dev.h
index a0cca02032e..173fad2ab24 100644
--- a/drivers/net/wireless/iwlwifi/iwl-dev.h
+++ b/drivers/net/wireless/iwlwifi/iwl-dev.h
@@ -1257,6 +1257,10 @@ struct iwl_trans_ops {
 
         int (*send_cmd_pdu)(struct iwl_priv *priv, u8 id, u32 flags, u16 len,
                      const void *data);
+        struct iwl_tx_cmd * (*get_tx_cmd)(struct iwl_priv *priv, int txq_id);
+        int (*tx)(struct iwl_priv *priv, struct sk_buff *skb,
+                struct iwl_tx_cmd *tx_cmd, int txq_id, __le16 fc, bool ampdu,
+                struct iwl_rxon_context *ctx);
 };
 
 struct iwl_trans {
diff --git a/drivers/net/wireless/iwlwifi/iwl-trans.c b/drivers/net/wireless/iwlwifi/iwl-trans.c
index d760857c863..acd2a5feec9 100644
--- a/drivers/net/wireless/iwlwifi/iwl-trans.c
+++ b/drivers/net/wireless/iwlwifi/iwl-trans.c
@@ -552,6 +552,159 @@ static int iwl_trans_tx_stop(struct iwl_priv *priv)
         return 0;
 }
 
+static struct iwl_tx_cmd *iwl_trans_get_tx_cmd(struct iwl_priv *priv,
+                                                int txq_id)
+{
+        struct iwl_tx_queue *txq = &priv->txq[txq_id];
+        struct iwl_queue *q = &txq->q;
+        struct iwl_device_cmd *dev_cmd;
+
+        if (unlikely(iwl_queue_space(q) < q->high_mark))
+                return NULL;
+
+        /*
+         * Set up the Tx-command (not MAC!) header.
+         * Store the chosen Tx queue and TFD index within the sequence field;
+         * after Tx, uCode's Tx response will return this value so driver can
+         * locate the frame within the tx queue and do post-tx processing.
+         */
+        dev_cmd = txq->cmd[q->write_ptr];
+        memset(dev_cmd, 0, sizeof(*dev_cmd));
+        dev_cmd->hdr.cmd = REPLY_TX;
+        dev_cmd->hdr.sequence = cpu_to_le16((u16)(QUEUE_TO_SEQ(txq_id) |
+                                INDEX_TO_SEQ(q->write_ptr)));
+        return &dev_cmd->cmd.tx;
+}
+
+static int iwl_trans_tx(struct iwl_priv *priv, struct sk_buff *skb,
+                struct iwl_tx_cmd *tx_cmd, int txq_id, __le16 fc, bool ampdu,
+                struct iwl_rxon_context *ctx)
+{
+        struct iwl_tx_queue *txq = &priv->txq[txq_id];
+        struct iwl_queue *q = &txq->q;
+        struct iwl_device_cmd *dev_cmd = txq->cmd[q->write_ptr];
+        struct iwl_cmd_meta *out_meta;
+
+        dma_addr_t phys_addr = 0;
+        dma_addr_t txcmd_phys;
+        dma_addr_t scratch_phys;
+        u16 len, firstlen, secondlen;
+        u8 wait_write_ptr = 0;
+        u8 hdr_len = ieee80211_hdrlen(fc);
+
+        /* Set up driver data for this TFD */
+        memset(&(txq->txb[q->write_ptr]), 0, sizeof(struct iwl_tx_info));
+        txq->txb[q->write_ptr].skb = skb;
+        txq->txb[q->write_ptr].ctx = ctx;
+
+        /* Set up first empty entry in queue's array of Tx/cmd buffers */
+        out_meta = &txq->meta[q->write_ptr];
+
+        /*
+         * Use the first empty entry in this queue's command buffer array
+         * to contain the Tx command and MAC header concatenated together
+         * (payload data will be in another buffer).
+         * Size of this varies, due to varying MAC header length.
+         * If end is not dword aligned, we'll have 2 extra bytes at the end
+         * of the MAC header (device reads on dword boundaries).
+         * We'll tell device about this padding later.
+         */
+        len = sizeof(struct iwl_tx_cmd) +
+                sizeof(struct iwl_cmd_header) + hdr_len;
+        firstlen = (len + 3) & ~3;
+
+        /* Tell NIC about any 2-byte padding after MAC header */
+        if (firstlen != len)
+                tx_cmd->tx_flags |= TX_CMD_FLG_MH_PAD_MSK;
+
+        /* Physical address of this Tx command's header (not MAC header!),
+         * within command buffer array. */
+        txcmd_phys = dma_map_single(priv->bus.dev,
+                                    &dev_cmd->hdr, firstlen,
+                                    DMA_BIDIRECTIONAL);
+        if (unlikely(dma_mapping_error(priv->bus.dev, txcmd_phys)))
+                return -1;
+        dma_unmap_addr_set(out_meta, mapping, txcmd_phys);
+        dma_unmap_len_set(out_meta, len, firstlen);
+
+        if (!ieee80211_has_morefrags(fc)) {
+                txq->need_update = 1;
+        } else {
+                wait_write_ptr = 1;
+                txq->need_update = 0;
+        }
+
+        /* Set up TFD's 2nd entry to point directly to remainder of skb,
+         * if any (802.11 null frames have no payload). */
+        secondlen = skb->len - hdr_len;
+        if (secondlen > 0) {
+                phys_addr = dma_map_single(priv->bus.dev, skb->data + hdr_len,
+                                           secondlen, DMA_TO_DEVICE);
+                if (unlikely(dma_mapping_error(priv->bus.dev, phys_addr))) {
+                        dma_unmap_single(priv->bus.dev,
+                                         dma_unmap_addr(out_meta, mapping),
+                                         dma_unmap_len(out_meta, len),
+                                         DMA_BIDIRECTIONAL);
+                        return -1;
+                }
+        }
+
+        /* Attach buffers to TFD */
+        iwlagn_txq_attach_buf_to_tfd(priv, txq, txcmd_phys, firstlen, 1);
+        if (secondlen > 0)
+                iwlagn_txq_attach_buf_to_tfd(priv, txq, phys_addr,
+                                             secondlen, 0);
+
+        scratch_phys = txcmd_phys + sizeof(struct iwl_cmd_header) +
+                                offsetof(struct iwl_tx_cmd, scratch);
+
+        /* take back ownership of DMA buffer to enable update */
+        dma_sync_single_for_cpu(priv->bus.dev, txcmd_phys, firstlen,
+                        DMA_BIDIRECTIONAL);
+        tx_cmd->dram_lsb_ptr = cpu_to_le32(scratch_phys);
+        tx_cmd->dram_msb_ptr = iwl_get_dma_hi_addr(scratch_phys);
+
+        IWL_DEBUG_TX(priv, "sequence nr = 0X%x\n",
+                     le16_to_cpu(dev_cmd->hdr.sequence));
+        IWL_DEBUG_TX(priv, "tx_flags = 0X%x\n", le32_to_cpu(tx_cmd->tx_flags));
+        iwl_print_hex_dump(priv, IWL_DL_TX, (u8 *)tx_cmd, sizeof(*tx_cmd));
+        iwl_print_hex_dump(priv, IWL_DL_TX, (u8 *)tx_cmd->hdr, hdr_len);
+
+        /* Set up entry for this TFD in Tx byte-count array */
+        if (ampdu)
+                iwlagn_txq_update_byte_cnt_tbl(priv, txq,
+                                               le16_to_cpu(tx_cmd->len));
+
+        dma_sync_single_for_device(priv->bus.dev, txcmd_phys, firstlen,
+                        DMA_BIDIRECTIONAL);
+
+        trace_iwlwifi_dev_tx(priv,
+                             &((struct iwl_tfd *)txq->tfds)[txq->q.write_ptr],
+                             sizeof(struct iwl_tfd),
+                             &dev_cmd->hdr, firstlen,
+                             skb->data + hdr_len, secondlen);
+
+        /* Tell device the write index *just past* this latest filled TFD */
+        q->write_ptr = iwl_queue_inc_wrap(q->write_ptr, q->n_bd);
+        iwl_txq_update_write_ptr(priv, txq);
+
+        /*
+         * At this point the frame is "transmitted" successfully
+         * and we will get a TX status notification eventually,
+         * regardless of the value of ret. "ret" only indicates
+         * whether or not we should update the write pointer.
+         */
+        if ((iwl_queue_space(q) < q->high_mark) && priv->mac80211_registered) {
+                if (wait_write_ptr) {
+                        txq->need_update = 1;
+                        iwl_txq_update_write_ptr(priv, txq);
+                } else {
+                        iwl_stop_queue(priv, txq);
+                }
+        }
+        return 0;
+}
+
 static const struct iwl_trans_ops trans_ops = {
         .rx_init = iwl_trans_rx_init,
         .rx_stop = iwl_trans_rx_stop,
@@ -563,6 +716,9 @@ static const struct iwl_trans_ops trans_ops = {
 
         .send_cmd = iwl_send_cmd,
         .send_cmd_pdu = iwl_send_cmd_pdu,
+
+        .get_tx_cmd = iwl_trans_get_tx_cmd,
+        .tx = iwl_trans_tx,
 };
 
 void iwl_trans_register(struct iwl_trans *trans)
diff --git a/drivers/net/wireless/iwlwifi/iwl-trans.h b/drivers/net/wireless/iwlwifi/iwl-trans.h
index 111acca07d7..f10bee8c1f8 100644
--- a/drivers/net/wireless/iwlwifi/iwl-trans.h
+++ b/drivers/net/wireless/iwlwifi/iwl-trans.h
@@ -102,4 +102,17 @@ static inline int trans_send_cmd_pdu(struct iwl_priv *priv, u8 id, u32 flags,
         return priv->trans.ops->send_cmd_pdu(priv, id, flags, len, data);
 }
 
+static inline struct iwl_tx_cmd *trans_get_tx_cmd(struct iwl_priv *priv,
+                                        int txq_id)
+{
+        return priv->trans.ops->get_tx_cmd(priv, txq_id);
+}
+
+static inline int trans_tx(struct iwl_priv *priv, struct sk_buff *skb,
+                struct iwl_tx_cmd *tx_cmd, int txq_id, __le16 fc, bool ampdu,
+                struct iwl_rxon_context *ctx)
+{
+        return priv->trans.ops->tx(priv, skb, tx_cmd, txq_id, fc, ampdu, ctx);
+}
+
 void iwl_trans_register(struct iwl_trans *trans);