rtlwifi: cleanup the code that check whether TX ring is available

Remove the duplicate checking of TX ring's available number, and remove
the variable to store available number that can be calculated by
read/write pointers.

Signed-off-by: Steven Ting <steventing@realtek.com>
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/realtek/rtlwifi/pci.c

@@ -557,13 +557,6 @@ static void _rtl_pci_tx_isr(struct ieee80211_hw *hw, int prio)
 		else
 			entry = (u8 *)(&ring->desc[ring->idx]);
 
-		if (rtlpriv->cfg->ops->get_available_desc &&
-		    rtlpriv->cfg->ops->get_available_desc(hw, prio) <= 1) {
-			RT_TRACE(rtlpriv, (COMP_INTR | COMP_SEND), DBG_DMESG,
-				 "no available desc!\n");
-			return;
-		}
-
 		if (!rtlpriv->cfg->ops->is_tx_desc_closed(hw, prio, ring->idx))
 			return;
 		ring->idx = (ring->idx + 1) % ring->entries;
@@ -1250,7 +1243,6 @@ static int _rtl_pci_init_tx_ring(struct ieee80211_hw *hw,
 
 		rtlpci->tx_ring[prio].cur_tx_rp = 0;
 		rtlpci->tx_ring[prio].cur_tx_wp = 0;
-		rtlpci->tx_ring[prio].avl_desc = entries;
 	}
 
 	/* alloc dma for this ring */

drivers/net/wireless/realtek/rtlwifi/pci.h

@@ -173,7 +173,6 @@ struct rtl8192_tx_ring {
 	/*add for new trx flow*/
 	struct rtl_tx_buffer_desc *buffer_desc; /*tx buffer descriptor*/
 	dma_addr_t buffer_desc_dma; /*tx bufferd desc dma memory*/
-	u16 avl_desc; /* available_desc_to_write */
 	u16 cur_tx_wp; /* current_tx_write_point */
 	u16 cur_tx_rp; /* current_tx_read_point */
 };

drivers/net/wireless/realtek/rtlwifi/rtl8192ee/trx.c

@@ -549,7 +549,6 @@ static u16 get_desc_addr_fr_q_idx(u16 queue_index)
 
 u16 rtl92ee_get_available_desc(struct ieee80211_hw *hw, u8 q_idx)
 {
-	struct rtl_pci *rtlpci = rtl_pcidev(rtl_pcipriv(hw));
 	struct rtl_priv *rtlpriv = rtl_priv(hw);
 	u16 point_diff = 0;
 	u16 current_tx_read_point = 0, current_tx_write_point = 0;
@@ -564,7 +563,6 @@ u16 rtl92ee_get_available_desc(struct ieee80211_hw *hw, u8 q_idx)
 				     current_tx_write_point,
 				     TX_DESC_NUM_92E);
 
-	rtlpci->tx_ring[q_idx].avl_desc = point_diff;
 	return point_diff;
 }
 
@@ -909,10 +907,6 @@ void rtl92ee_set_desc(struct ieee80211_hw *hw, u8 *pdesc, bool istx,
 		      u8 desc_name, u8 *val)
 {
 	struct rtl_priv *rtlpriv = rtl_priv(hw);
-	u16 cur_tx_rp = 0;
-	u16 cur_tx_wp = 0;
-	static bool over_run;
-	u32 tmp = 0;
 	u8 q_idx = *val;
 	bool dma64 = rtlpriv->cfg->mod_params->dma64;
 
@@ -933,38 +927,12 @@ void rtl92ee_set_desc(struct ieee80211_hw *hw, u8 *pdesc, bool istx,
 				return;
 			}
 
+			/* make sure tx desc is available by caller */
 			ring->cur_tx_wp = ((ring->cur_tx_wp + 1) % max_tx_desc);
 
-			if (over_run) {
-				ring->cur_tx_wp = 0;
-				over_run = false;
-			}
-			if (ring->avl_desc > 1) {
-				ring->avl_desc--;
-
-				rtl_write_word(rtlpriv,
-					       get_desc_addr_fr_q_idx(q_idx),
-					       ring->cur_tx_wp);
-			}
-
-			if (ring->avl_desc < (max_tx_desc - 15)) {
-				u16 point_diff = 0;
-
-				tmp =
-				  rtl_read_dword(rtlpriv,
-						 get_desc_addr_fr_q_idx(q_idx));
-				cur_tx_rp = (u16)((tmp >> 16) & 0x0fff);
-				cur_tx_wp = (u16)(tmp & 0x0fff);
-
-				ring->cur_tx_wp = cur_tx_wp;
-				ring->cur_tx_rp = cur_tx_rp;
-				point_diff = ((cur_tx_rp > cur_tx_wp) ?
-					      (cur_tx_rp - cur_tx_wp) :
-					      (TX_DESC_NUM_92E - 1 -
-					       cur_tx_wp + cur_tx_rp));
-
-				ring->avl_desc = point_diff;
-			}
+			rtl_write_word(rtlpriv,
+				       get_desc_addr_fr_q_idx(q_idx),
+				       ring->cur_tx_wp);
 		}
 		break;
 		}
@@ -1046,13 +1014,12 @@ bool rtl92ee_is_tx_desc_closed(struct ieee80211_hw *hw, u8 hw_queue, u16 index)
 {
 	struct rtl_pci *rtlpci = rtl_pcidev(rtl_pcipriv(hw));
 	struct rtl_priv *rtlpriv = rtl_priv(hw);
-	u16 read_point, write_point, available_desc_num;
+	u16 read_point, write_point;
 	bool ret = false;
 	static u8 stop_report_cnt;
 	struct rtl8192_tx_ring *ring = &rtlpci->tx_ring[hw_queue];
 
 	{
-		u16 point_diff = 0;
 		u16 cur_tx_rp, cur_tx_wp;
 		u32 tmpu32 = 0;
 
@@ -1062,18 +1029,12 @@ bool rtl92ee_is_tx_desc_closed(struct ieee80211_hw *hw, u8 hw_queue, u16 index)
 		cur_tx_rp = (u16)((tmpu32 >> 16) & 0x0fff);
 		cur_tx_wp = (u16)(tmpu32 & 0x0fff);
 
-		ring->cur_tx_wp = cur_tx_wp;
+		/* don't need to update ring->cur_tx_wp */
 		ring->cur_tx_rp = cur_tx_rp;
-		point_diff = ((cur_tx_rp > cur_tx_wp) ?
-			      (cur_tx_rp - cur_tx_wp) :
-			      (TX_DESC_NUM_92E - cur_tx_wp + cur_tx_rp));
-
-		ring->avl_desc = point_diff;
 	}
 
 	read_point = ring->cur_tx_rp;
 	write_point = ring->cur_tx_wp;
-	available_desc_num = ring->avl_desc;
 
 	if (write_point > read_point) {
 		if (index < write_point && index >= read_point)