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>

1 files changed, 15 insertions, 3 deletions

diff --git a/drivers/net/wireless/iwlwifi/iwl4965-base.c b/drivers/net/wireless/iwlwifi/iwl4965-base.c
index 74c3d3917fe1..66aa938e316e 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;