wl1271: Improvements to the TX path

- Fix a TX result overflow problem that was present in the TX path and visible
  with at least linksys AP's (probably any AP with high throughput capability.)
- Optimize TX by writing FW trigger for a group of TX frames instead of
  each and every frame.
- Slightly optimize the TX path code.

Signed-off-by: Juuso Oikarinen <juuso.oikarinen@nokia.com>
Reviewed-by: Kalle Valo <kalle.valo@nokia.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

4 files changed, 29 insertions, 23 deletions

diff --git a/drivers/net/wireless/wl12xx/wl1271.h b/drivers/net/wireless/wl12xx/wl1271.h
index 10135c94e20e..cc974eae009e 100644
--- a/drivers/net/wireless/wl12xx/wl1271.h
+++ b/drivers/net/wireless/wl12xx/wl1271.h
@@ -396,10 +396,10 @@ struct wl1271 {
         /* Accounting for allocated / available TX blocks on HW */
         u32 tx_blocks_freed[NUM_TX_QUEUES];
         u32 tx_blocks_available;
-        u8 tx_results_count;
+        u32 tx_results_count;
 
         /* Transmitted TX packets counter for chipset interface */
-        int tx_packets_count;
+        u32 tx_packets_count;
 
         /* Time-offset between host and chipset clocks */
         int time_offset;
diff --git a/drivers/net/wireless/wl12xx/wl1271_main.c b/drivers/net/wireless/wl12xx/wl1271_main.c
index 310f58c66231..5cc778f658b9 100644
--- a/drivers/net/wireless/wl12xx/wl1271_main.c
+++ b/drivers/net/wireless/wl12xx/wl1271_main.c
@@ -453,14 +453,12 @@ static void wl1271_irq_work(struct work_struct *work)
                 wl1271_debug(DEBUG_IRQ, "WL1271_ACX_INTR_HW_AVAILABLE");
 
         if (intr & WL1271_ACX_INTR_DATA) {
-                u8 tx_res_cnt = wl->fw_status->tx_results_counter -
-                        wl->tx_results_count;
-
                 wl1271_debug(DEBUG_IRQ, "WL1271_ACX_INTR_DATA");
 
                 /* check for tx results */
-                if (tx_res_cnt)
-                        wl1271_tx_complete(wl, tx_res_cnt);
+                if (wl->fw_status->tx_results_counter !=
+                    (wl->tx_results_count & 0xff))
+                        wl1271_tx_complete(wl);
 
                 wl1271_rx(wl, wl->fw_status);
         }
diff --git a/drivers/net/wireless/wl12xx/wl1271_tx.c b/drivers/net/wireless/wl12xx/wl1271_tx.c
index 2b7dd9b76fe1..2e057b0e3257 100644
--- a/drivers/net/wireless/wl12xx/wl1271_tx.c
+++ b/drivers/net/wireless/wl12xx/wl1271_tx.c
@@ -169,7 +169,6 @@ static int wl1271_tx_send_packet(struct wl1271 *wl, struct sk_buff *skb,
 
         /* write packet new counter into the write access register */
         wl->tx_packets_count++;
-        wl1271_write32(wl, WL1271_HOST_WR_ACCESS, wl->tx_packets_count);
 
         desc = (struct wl1271_tx_hw_descr *) skb->data;
         wl1271_debug(DEBUG_TX, "tx id %u skb 0x%p payload %u (%u words)",
@@ -244,6 +243,7 @@ void wl1271_tx_work(struct work_struct *work)
         struct sk_buff *skb;
         bool woken_up = false;
         u32 sta_rates = 0;
+        u32 prev_tx_packets_count;
         int ret;
 
         /* check if the rates supported by the AP have changed */
@@ -260,6 +260,8 @@ void wl1271_tx_work(struct work_struct *work)
         if (unlikely(wl->state == WL1271_STATE_OFF))
                 goto out;
 
+        prev_tx_packets_count = wl->tx_packets_count;
+
         /* if rates have changed, re-configure the rate policy */
         if (unlikely(sta_rates)) {
                 wl->rate_set = wl1271_tx_enabled_rates_get(wl, sta_rates);
@@ -270,7 +272,7 @@ void wl1271_tx_work(struct work_struct *work)
                 if (!woken_up) {
                         ret = wl1271_ps_elp_wakeup(wl, false);
                         if (ret < 0)
-                                goto out;
+                                goto out_ack;
                         woken_up = true;
                 }
 
@@ -282,10 +284,10 @@ void wl1271_tx_work(struct work_struct *work)
                         ieee80211_stop_queues(wl->hw);
                         set_bit(WL1271_FLAG_TX_QUEUE_STOPPED, &wl->flags);
                         skb_queue_head(&wl->tx_queue, skb);
-                        goto out;
+                        goto out_ack;
                 } else if (ret < 0) {
                         dev_kfree_skb(skb);
-                        goto out;
+                        goto out_ack;
                 } else if (test_and_clear_bit(WL1271_FLAG_TX_QUEUE_STOPPED,
                                               &wl->flags)) {
                         /* firmware buffer has space, restart queues */
@@ -295,6 +297,11 @@ void wl1271_tx_work(struct work_struct *work)
                 }
         }
 
+out_ack:
+        /* interrupt the firmware with the new packets */
+        if (prev_tx_packets_count != wl->tx_packets_count)
+                wl1271_write32(wl, WL1271_HOST_WR_ACCESS, wl->tx_packets_count);
+
 out:
         if (woken_up)
                 wl1271_ps_elp_sleep(wl);
@@ -311,7 +318,7 @@ static void wl1271_tx_complete_packet(struct wl1271 *wl,
         int id = result->id;
 
         /* check for id legality */
-        if (id >= ACX_TX_DESCRIPTORS || wl->tx_frames[id] == NULL) {
+        if (unlikely(id >= ACX_TX_DESCRIPTORS || wl->tx_frames[id] == NULL)) {
                 wl1271_warning("TX result illegal id: %d", id);
                 return;
         }
@@ -366,10 +373,11 @@ static void wl1271_tx_complete_packet(struct wl1271 *wl,
 }
 
 /* Called upon reception of a TX complete interrupt */
-void wl1271_tx_complete(struct wl1271 *wl, u32 count)
+void wl1271_tx_complete(struct wl1271 *wl)
 {
         struct wl1271_acx_mem_map *memmap =
                 (struct wl1271_acx_mem_map *)wl->target_mem_map;
+        u32 count, fw_counter;
         u32 i;
 
         wl1271_debug(DEBUG_TX, "tx_complete received, packets: %d", count);
@@ -377,12 +385,18 @@ void wl1271_tx_complete(struct wl1271 *wl, u32 count)
         /* read the tx results from the chipset */
         wl1271_read(wl, le32_to_cpu(memmap->tx_result),
                     wl->tx_res_if, sizeof(*wl->tx_res_if), false);
+        fw_counter = le32_to_cpu(wl->tx_res_if->tx_result_fw_counter);
+
+        /* write host counter to chipset (to ack) */
+        wl1271_write32(wl, le32_to_cpu(memmap->tx_result) +
+                       offsetof(struct wl1271_tx_hw_res_if,
+                                tx_result_host_counter), fw_counter);
+
+        count = fw_counter - wl->tx_results_count;
 
         /* verify that the result buffer is not getting overrun */
-        if (count > TX_HW_RESULT_QUEUE_LEN) {
+        if (unlikely(count > TX_HW_RESULT_QUEUE_LEN))
                 wl1271_warning("TX result overflow from chipset: %d", count);
-                count = TX_HW_RESULT_QUEUE_LEN;
-        }
 
         /* process the results */
         for (i = 0; i < count; i++) {
@@ -395,12 +409,6 @@ void wl1271_tx_complete(struct wl1271 *wl, u32 count)
 
                 wl->tx_results_count++;
         }
-
-        /* write host counter to chipset (to ack) */
-        wl1271_write32(wl, le32_to_cpu(memmap->tx_result) +
-                       offsetof(struct wl1271_tx_hw_res_if,
-                       tx_result_host_counter),
-                       le32_to_cpu(wl->tx_res_if->tx_result_fw_counter));
 }
 
 /* caller must hold wl->mutex */
diff --git a/drivers/net/wireless/wl12xx/wl1271_tx.h b/drivers/net/wireless/wl12xx/wl1271_tx.h
index 17e405a09caa..ca92bd811292 100644
--- a/drivers/net/wireless/wl12xx/wl1271_tx.h
+++ b/drivers/net/wireless/wl12xx/wl1271_tx.h
@@ -160,7 +160,7 @@ static inline int wl1271_tx_ac_to_tid(int ac)
 }
 
 void wl1271_tx_work(struct work_struct *work);
-void wl1271_tx_complete(struct wl1271 *wl, u32 count);
+void wl1271_tx_complete(struct wl1271 *wl);
 void wl1271_tx_flush(struct wl1271 *wl);
 
 #endif