netdev - [PATCH for 3.19 2/3] rtlwifi: Fix handling of new style descriptors

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Date:	Wed, 14 Jan 2015 11:37:15 -0600
From:	Larry Finger <Larry.Finger@...inger.net>
To:	kvalo@...eaurora.org
Cc:	linux-wireless@...r.kernel.org, Troy Tan <troy_tan@...lsil.com.cn>,
	netdev@...r.kernel.org, Larry Finger <Larry.Finger@...inger.net>
Subject: [PATCH for 3.19 2/3] rtlwifi: Fix handling of new style descriptors

From: Troy Tan <troy_tan@...lsil.com.cn>

The hardware and firmware for the RTL8192EE utilize a FIFO list of
descriptors. There were some problems with the initial implementation.
The worst of these failed to detect that the FIFO was becoming full,
which led to the device needing to be power cycled. As this condition
is not relevant to most of the devices supported by rtlwifi, a callback
routine was added to detect this situation. This patch implements the
necessary changes in the pci handler.

Signed-off-by: Troy Tan <troy_tan@...lsil.com.cn>
Signed-off-by: Larry Finger <Larry.Finger@...inger.net>
---
 drivers/net/wireless/rtlwifi/pci.c  | 31 +++++++++++++++++++++++--------
 drivers/net/wireless/rtlwifi/wifi.h |  1 +
 2 files changed, 24 insertions(+), 8 deletions(-)

diff --git a/drivers/net/wireless/rtlwifi/pci.c b/drivers/net/wireless/rtlwifi/pci.c
index e25faac..a62170e 100644
--- a/drivers/net/wireless/rtlwifi/pci.c
+++ b/drivers/net/wireless/rtlwifi/pci.c
@@ -578,6 +578,13 @@ 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;
@@ -641,10 +648,9 @@ static void _rtl_pci_tx_isr(struct ieee80211_hw *hw, int prio)
 
 		ieee80211_tx_status_irqsafe(hw, skb);
 
-		if ((ring->entries - skb_queue_len(&ring->queue))
-				== 2) {
+		if ((ring->entries - skb_queue_len(&ring->queue)) <= 4) {
 
-			RT_TRACE(rtlpriv, COMP_ERR, DBG_LOUD,
+			RT_TRACE(rtlpriv, COMP_ERR, DBG_DMESG,
 				 "more desc left, wake skb_queue@%d, ring->idx = %d, skb_queue_len = 0x%x\n",
 				 prio, ring->idx,
 				 skb_queue_len(&ring->queue));
@@ -793,7 +799,7 @@ static void _rtl_pci_rx_interrupt(struct ieee80211_hw *hw)
 			rx_remained_cnt =
 				rtlpriv->cfg->ops->rx_desc_buff_remained_cnt(hw,
 								      hw_queue);
-			if (rx_remained_cnt < 1)
+			if (rx_remained_cnt == 0)
 				return;
 
 		} else {	/* rx descriptor */
@@ -845,18 +851,18 @@ static void _rtl_pci_rx_interrupt(struct ieee80211_hw *hw)
 			else
 				skb_reserve(skb, stats.rx_drvinfo_size +
 					    stats.rx_bufshift);
-
 		} else {
 			RT_TRACE(rtlpriv, COMP_ERR, DBG_WARNING,
 				 "skb->end - skb->tail = %d, len is %d\n",
 				 skb->end - skb->tail, len);
-			break;
+			dev_kfree_skb_any(skb);
+			goto new_trx_end;
 		}
 		/* handle command packet here */
 		if (rtlpriv->cfg->ops->rx_command_packet &&
 		    rtlpriv->cfg->ops->rx_command_packet(hw, stats, skb)) {
 				dev_kfree_skb_any(skb);
-				goto end;
+				goto new_trx_end;
 		}
 
 		/*
@@ -906,6 +912,7 @@ static void _rtl_pci_rx_interrupt(struct ieee80211_hw *hw)
 		} else {
 			dev_kfree_skb_any(skb);
 		}
+new_trx_end:
 		if (rtlpriv->use_new_trx_flow) {
 			rtlpci->rx_ring[hw_queue].next_rx_rp += 1;
 			rtlpci->rx_ring[hw_queue].next_rx_rp %=
@@ -921,7 +928,6 @@ static void _rtl_pci_rx_interrupt(struct ieee80211_hw *hw)
 			rtlpriv->enter_ps = false;
 			schedule_work(&rtlpriv->works.lps_change_work);
 		}
-end:
 		skb = new_skb;
 no_new:
 		if (rtlpriv->use_new_trx_flow) {
@@ -1685,6 +1691,15 @@ static int rtl_pci_tx(struct ieee80211_hw *hw,
 		}
 	}
 
+	if (rtlpriv->cfg->ops->get_available_desc &&
+	    rtlpriv->cfg->ops->get_available_desc(hw, hw_queue) == 0) {
+			RT_TRACE(rtlpriv, COMP_ERR, DBG_WARNING,
+				 "get_available_desc fail\n");
+			spin_unlock_irqrestore(&rtlpriv->locks.irq_th_lock,
+					       flags);
+			return skb->len;
+	}
+
 	if (ieee80211_is_data_qos(fc)) {
 		tid = rtl_get_tid(skb);
 		if (sta) {
diff --git a/drivers/net/wireless/rtlwifi/wifi.h b/drivers/net/wireless/rtlwifi/wifi.h
index 3b3453a..413c2ab 100644
--- a/drivers/net/wireless/rtlwifi/wifi.h
+++ b/drivers/net/wireless/rtlwifi/wifi.h
@@ -2172,6 +2172,7 @@ struct rtl_hal_ops {
 	void (*add_wowlan_pattern)(struct ieee80211_hw *hw,
 				   struct rtl_wow_pattern *rtl_pattern,
 				   u8 index);
+	u16 (*get_available_desc)(struct ieee80211_hw *hw, u8 q_idx);
 };
 
 struct rtl_intf_ops {
-- 
2.1.2

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