iwlwifi: pcie: get rid of q->n_bd

This variable always tracks a constant value (256) so there's
no need to have it. Removing it simplifies code generation,
reducing the .text size (by about 240 bytes on x86-64.)

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>

4 files changed, 45 insertions, 53 deletions

diff --git a/drivers/net/wireless/iwlwifi/pcie/internal.h b/drivers/net/wireless/iwlwifi/pcie/internal.h
index 1b95d856dfd5..ab21aee0a51d 100644
--- a/drivers/net/wireless/iwlwifi/pcie/internal.h
+++ b/drivers/net/wireless/iwlwifi/pcie/internal.h
@@ -117,21 +117,19 @@ struct iwl_dma_ptr {
 /**
  * iwl_queue_inc_wrap - increment queue index, wrap back to beginning
  * @index -- current index
- * @n_bd -- total number of entries in queue (must be power of 2)
  */
-static inline int iwl_queue_inc_wrap(int index, int n_bd)
+static inline int iwl_queue_inc_wrap(int index)
 {
-        return ++index & (n_bd - 1);
+        return ++index & (TFD_QUEUE_SIZE_MAX - 1);
 }
 
 /**
  * iwl_queue_dec_wrap - decrement queue index, wrap back to end
  * @index -- current index
- * @n_bd -- total number of entries in queue (must be power of 2)
  */
-static inline int iwl_queue_dec_wrap(int index, int n_bd)
+static inline int iwl_queue_dec_wrap(int index)
 {
-        return --index & (n_bd - 1);
+        return --index & (TFD_QUEUE_SIZE_MAX - 1);
 }
 
 struct iwl_cmd_meta {
@@ -145,13 +143,13 @@ struct iwl_cmd_meta {
  *
  * Contains common data for Rx and Tx queues.
  *
- * Note the difference between n_bd and n_window: the hardware
- * always assumes 256 descriptors, so n_bd is always 256 (unless
+ * Note the difference between TFD_QUEUE_SIZE_MAX and n_window: the hardware
+ * always assumes 256 descriptors, so TFD_QUEUE_SIZE_MAX is always 256 (unless
  * there might be HW changes in the future). For the normal TX
  * queues, n_window, which is the size of the software queue data
  * is also 256; however, for the command queue, n_window is only
  * 32 since we don't need so many commands pending. Since the HW
- * still uses 256 BDs for DMA though, n_bd stays 256. As a result,
+ * still uses 256 BDs for DMA though, TFD_QUEUE_SIZE_MAX stays 256. As a result,
  * the software buffers (in the variables @meta, @txb in struct
  * iwl_txq) only have 32 entries, while the HW buffers (@tfds in
  * the same struct) have 256.
@@ -162,7 +160,6 @@ struct iwl_cmd_meta {
  * data is a window overlayed over the HW queue.
  */
 struct iwl_queue {
-        int n_bd;              /* number of BDs in this queue */
         int write_ptr;       /* 1-st empty entry (index) host_w*/
         int read_ptr;         /* last used entry (index) host_r*/
         /* use for monitoring and recovering the stuck queue */
diff --git a/drivers/net/wireless/iwlwifi/pcie/rx.c b/drivers/net/wireless/iwlwifi/pcie/rx.c
index 4a26a082a1ba..a2698e5e062c 100644
--- a/drivers/net/wireless/iwlwifi/pcie/rx.c
+++ b/drivers/net/wireless/iwlwifi/pcie/rx.c
@@ -850,7 +850,7 @@ static u32 iwl_pcie_int_cause_ict(struct iwl_trans *trans)
                                 trans_pcie->ict_index, read);
                 trans_pcie->ict_tbl[trans_pcie->ict_index] = 0;
                 trans_pcie->ict_index =
-                        iwl_queue_inc_wrap(trans_pcie->ict_index, ICT_COUNT);
+                        ((trans_pcie->ict_index + 1) & (ICT_COUNT - 1));
 
                 read = le32_to_cpu(trans_pcie->ict_tbl[trans_pcie->ict_index]);
                 trace_iwlwifi_dev_ict_read(trans->dev, trans_pcie->ict_index,
diff --git a/drivers/net/wireless/iwlwifi/pcie/trans.c b/drivers/net/wireless/iwlwifi/pcie/trans.c
index f98ef1e62eb9..a6f86220e0aa 100644
--- a/drivers/net/wireless/iwlwifi/pcie/trans.c
+++ b/drivers/net/wireless/iwlwifi/pcie/trans.c
@@ -1337,8 +1337,8 @@ static int iwl_trans_pcie_wait_txq_empty(struct iwl_trans *trans, u32 txq_bm)
                 IWL_ERR(trans,
                         "Q %d is %sactive and mapped to fifo %d ra_tid 0x%04x [%d,%d]\n",
                         cnt, active ? "" : "in", fifo, tbl_dw,
-                        iwl_read_prph(trans,
-                                      SCD_QUEUE_RDPTR(cnt)) & (txq->q.n_bd - 1),
+                        iwl_read_prph(trans, SCD_QUEUE_RDPTR(cnt)) &
+                                (TFD_QUEUE_SIZE_MAX - 1),
                         iwl_read_prph(trans, SCD_QUEUE_WRPTR(cnt)));
         }
 
diff --git a/drivers/net/wireless/iwlwifi/pcie/tx.c b/drivers/net/wireless/iwlwifi/pcie/tx.c
index 16ebc4a9514d..93709fe28d76 100644
--- a/drivers/net/wireless/iwlwifi/pcie/tx.c
+++ b/drivers/net/wireless/iwlwifi/pcie/tx.c
@@ -70,20 +70,20 @@ static int iwl_queue_space(const struct iwl_queue *q)
 
         /*
          * To avoid ambiguity between empty and completely full queues, there
-         * should always be less than q->n_bd elements in the queue.
-         * If q->n_window is smaller than q->n_bd, there is no need to reserve
-         * any queue entries for this purpose.
+         * should always be less than TFD_QUEUE_SIZE_MAX elements in the queue.
+         * If q->n_window is smaller than TFD_QUEUE_SIZE_MAX, there is no need
+         * to reserve any queue entries for this purpose.
          */
-        if (q->n_window < q->n_bd)
+        if (q->n_window < TFD_QUEUE_SIZE_MAX)
                 max = q->n_window;
         else
-                max = q->n_bd - 1;
+                max = TFD_QUEUE_SIZE_MAX - 1;
 
         /*
-         * q->n_bd is a power of 2, so the following is equivalent to modulo by
-         * q->n_bd and is well defined for negative dividends.
+         * TFD_QUEUE_SIZE_MAX is a power of 2, so the following is equivalent to
+         * modulo by TFD_QUEUE_SIZE_MAX and is well defined.
          */
-        used = (q->write_ptr - q->read_ptr) & (q->n_bd - 1);
+        used = (q->write_ptr - q->read_ptr) & (TFD_QUEUE_SIZE_MAX - 1);
 
         if (WARN_ON(used > max))
                 return 0;
@@ -94,17 +94,11 @@ static int iwl_queue_space(const struct iwl_queue *q)
 /*
  * iwl_queue_init - Initialize queue's high/low-water and read/write indexes
  */
-static int iwl_queue_init(struct iwl_queue *q, int count, int slots_num, u32 id)
+static int iwl_queue_init(struct iwl_queue *q, int slots_num, u32 id)
 {
-        q->n_bd = count;
         q->n_window = slots_num;
         q->id = id;
 
-        /* count must be power-of-two size, otherwise iwl_queue_inc_wrap
-         * and iwl_queue_dec_wrap are broken. */
-        if (WARN_ON(!is_power_of_2(count)))
-                return -EINVAL;
-
         /* slots_num must be power-of-two size, otherwise
          * get_cmd_index is broken. */
         if (WARN_ON(!is_power_of_2(slots_num)))
@@ -197,13 +191,13 @@ static void iwl_pcie_txq_stuck_timer(unsigned long data)
                 IWL_ERR(trans,
                         "Q %d is %sactive and mapped to fifo %d ra_tid 0x%04x [%d,%d]\n",
                         i, active ? "" : "in", fifo, tbl_dw,
-                        iwl_read_prph(trans,
-                                      SCD_QUEUE_RDPTR(i)) & (txq->q.n_bd - 1),
+                        iwl_read_prph(trans, SCD_QUEUE_RDPTR(i)) &
+                                (TFD_QUEUE_SIZE_MAX - 1),
                         iwl_read_prph(trans, SCD_QUEUE_WRPTR(i)));
         }
 
         for (i = q->read_ptr; i != q->write_ptr;
-             i = iwl_queue_inc_wrap(i, q->n_bd))
+             i = iwl_queue_inc_wrap(i))
                 IWL_ERR(trans, "scratch %d = 0x%08x\n", i,
                         le32_to_cpu(txq->scratchbufs[i].scratch));
 
@@ -425,13 +419,17 @@ static void iwl_pcie_txq_free_tfd(struct iwl_trans *trans, struct iwl_txq *txq)
 {
         struct iwl_tfd *tfd_tmp = txq->tfds;
 
-        /* rd_ptr is bounded by n_bd and idx is bounded by n_window */
+        /* rd_ptr is bounded by TFD_QUEUE_SIZE_MAX and
+         * idx is bounded by n_window
+         */
         int rd_ptr = txq->q.read_ptr;
         int idx = get_cmd_index(&txq->q, rd_ptr);
 
         lockdep_assert_held(&txq->lock);
 
-        /* We have only q->n_window txq->entries, but we use q->n_bd tfds */
+        /* We have only q->n_window txq->entries, but we use
+         * TFD_QUEUE_SIZE_MAX tfds
+         */
         iwl_pcie_tfd_unmap(trans, &txq->entries[idx].meta, &tfd_tmp[rd_ptr]);
 
         /* free SKB */
@@ -565,8 +563,7 @@ static int iwl_pcie_txq_init(struct iwl_trans *trans, struct iwl_txq *txq,
         BUILD_BUG_ON(TFD_QUEUE_SIZE_MAX & (TFD_QUEUE_SIZE_MAX - 1));
 
         /* Initialize queue's high/low-water marks, and head/tail indexes */
-        ret = iwl_queue_init(&txq->q, TFD_QUEUE_SIZE_MAX, slots_num,
-                        txq_id);
+        ret = iwl_queue_init(&txq->q, slots_num, txq_id);
         if (ret)
                 return ret;
 
@@ -591,15 +588,12 @@ static void iwl_pcie_txq_unmap(struct iwl_trans *trans, int txq_id)
         struct iwl_txq *txq = &trans_pcie->txq[txq_id];
         struct iwl_queue *q = &txq->q;
 
-        if (!q->n_bd)
-                return;
-
         spin_lock_bh(&txq->lock);
         while (q->write_ptr != q->read_ptr) {
                 IWL_DEBUG_TX_REPLY(trans, "Q %d Free %d\n",
                                    txq_id, q->read_ptr);
                 iwl_pcie_txq_free_tfd(trans, txq);
-                q->read_ptr = iwl_queue_inc_wrap(q->read_ptr, q->n_bd);
+                q->read_ptr = iwl_queue_inc_wrap(q->read_ptr);
         }
         txq->active = false;
         spin_unlock_bh(&txq->lock);
@@ -636,10 +630,12 @@ static void iwl_pcie_txq_free(struct iwl_trans *trans, int txq_id)
                 }
 
         /* De-alloc circular buffer of TFDs */
-        if (txq->q.n_bd) {
-                dma_free_coherent(dev, sizeof(struct iwl_tfd) *
-                                  txq->q.n_bd, txq->tfds, txq->q.dma_addr);
+        if (txq->tfds) {
+                dma_free_coherent(dev,
+                                  sizeof(struct iwl_tfd) * TFD_QUEUE_SIZE_MAX,
+                                  txq->tfds, txq->q.dma_addr);
                 txq->q.dma_addr = 0;
+                txq->tfds = NULL;
 
                 dma_free_coherent(dev,
                                   sizeof(*txq->scratchbufs) * txq->q.n_window,
@@ -948,8 +944,7 @@ void iwl_trans_pcie_reclaim(struct iwl_trans *trans, int txq_id, int ssn,
 {
         struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
         struct iwl_txq *txq = &trans_pcie->txq[txq_id];
-        /* n_bd is usually 256 => n_bd - 1 = 0xff */
-        int tfd_num = ssn & (txq->q.n_bd - 1);
+        int tfd_num = ssn & (TFD_QUEUE_SIZE_MAX - 1);
         struct iwl_queue *q = &txq->q;
         int last_to_free;
 
@@ -973,12 +968,12 @@ void iwl_trans_pcie_reclaim(struct iwl_trans *trans, int txq_id, int ssn,
 
         /*Since we free until index _not_ inclusive, the one before index is
          * the last we will free. This one must be used */
-        last_to_free = iwl_queue_dec_wrap(tfd_num, q->n_bd);
+        last_to_free = iwl_queue_dec_wrap(tfd_num);
 
         if (!iwl_queue_used(q, last_to_free)) {
                 IWL_ERR(trans,
                         "%s: Read index for DMA queue txq id (%d), last_to_free %d is out of range [0-%d] %d %d.\n",
-                        __func__, txq_id, last_to_free, q->n_bd,
+                        __func__, txq_id, last_to_free, TFD_QUEUE_SIZE_MAX,
                         q->write_ptr, q->read_ptr);
                 goto out;
         }
@@ -988,7 +983,7 @@ void iwl_trans_pcie_reclaim(struct iwl_trans *trans, int txq_id, int ssn,
 
         for (;
              q->read_ptr != tfd_num;
-             q->read_ptr = iwl_queue_inc_wrap(q->read_ptr, q->n_bd)) {
+             q->read_ptr = iwl_queue_inc_wrap(q->read_ptr)) {
 
                 if (WARN_ON_ONCE(txq->entries[txq->q.read_ptr].skb == NULL))
                         continue;
@@ -1027,16 +1022,16 @@ static void iwl_pcie_cmdq_reclaim(struct iwl_trans *trans, int txq_id, int idx)
 
         lockdep_assert_held(&txq->lock);
 
-        if ((idx >= q->n_bd) || (!iwl_queue_used(q, idx))) {
+        if ((idx >= TFD_QUEUE_SIZE_MAX) || (!iwl_queue_used(q, idx))) {
                 IWL_ERR(trans,
                         "%s: Read index for DMA queue txq id (%d), index %d is out of range [0-%d] %d %d.\n",
-                        __func__, txq_id, idx, q->n_bd,
+                        __func__, txq_id, idx, TFD_QUEUE_SIZE_MAX,
                         q->write_ptr, q->read_ptr);
                 return;
         }
 
-        for (idx = iwl_queue_inc_wrap(idx, q->n_bd); q->read_ptr != idx;
-             q->read_ptr = iwl_queue_inc_wrap(q->read_ptr, q->n_bd)) {
+        for (idx = iwl_queue_inc_wrap(idx); q->read_ptr != idx;
+             q->read_ptr = iwl_queue_inc_wrap(q->read_ptr)) {
 
                 if (nfreed++ > 0) {
                         IWL_ERR(trans, "HCMD skipped: index (%d) %d %d\n",
@@ -1445,7 +1440,7 @@ static int iwl_pcie_enqueue_hcmd(struct iwl_trans *trans,
         }
 
         /* Increment and update queue's write index */
-        q->write_ptr = iwl_queue_inc_wrap(q->write_ptr, q->n_bd);
+        q->write_ptr = iwl_queue_inc_wrap(q->write_ptr);
         iwl_pcie_txq_inc_wr_ptr(trans, txq);
 
         spin_unlock_irqrestore(&trans_pcie->reg_lock, flags);
@@ -1788,7 +1783,7 @@ int iwl_trans_pcie_tx(struct iwl_trans *trans, struct sk_buff *skb,
                 mod_timer(&txq->stuck_timer, jiffies + trans_pcie->wd_timeout);
 
         /* Tell device the write index *just past* this latest filled TFD */
-        q->write_ptr = iwl_queue_inc_wrap(q->write_ptr, q->n_bd);
+        q->write_ptr = iwl_queue_inc_wrap(q->write_ptr);
         if (!wait_write_ptr)
                 iwl_pcie_txq_inc_wr_ptr(trans, txq);