brcmsmac: Remove internal tx queue

The brcmsmac internal tx buffering is problematic. The amount of
buffering is excessive (228 packets in addition to the 256 slots in each
DMA ring), and frames may be dropped due to a lack of flow control.

This patch reworks the transmit code path to remove the internal
buffering. Frames are immediately handed off to the DMA support rather
than passing through an intermediate queue. Non-aggregate frames are
queued immediately into the tx rings, and aggregate frames are queued
temporarily in an AMPDU session until ready for transmit.

Transmit flow control is also added to avoid dropping packets when the
tx rings are full. Conceptually this is a separate change, but it's
included in this commit because removing the tx queue without adding
flow control could cause significant problems.

Signed-off-by: Seth Forshee <seth.forshee@canonical.com>
Reviewed-by: Pieter-Paul Giesberts <pieterpg@broadcom.com>
Reviewed-by: Arend van Spriel <arend@broadcom.com>
Tested-by: Daniel Wagner <wagi@monom.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 2 insertions, 31 deletions

diff --git a/drivers/net/wireless/brcm80211/brcmsmac/main.h b/drivers/net/wireless/brcm80211/brcmsmac/main.h
index 4e3af67c7dd7..8a58cc12d19d 100644
--- a/drivers/net/wireless/brcm80211/brcmsmac/main.h
+++ b/drivers/net/wireless/brcm80211/brcmsmac/main.h
@@ -239,7 +239,6 @@ struct brcms_core {
 
 	/* fifo */
 	uint *txavail[NFIFO];	/* # tx descriptors available */
-	s16 txpktpend[NFIFO];	/* tx admission control */
 
 	struct macstat *macstat_snapshot;	/* mac hw prev read values */
 };
@@ -379,19 +378,6 @@ struct brcms_hardware {
 				 */
 };
 
-/* TX Queue information
- *
- * Each flow of traffic out of the device has a TX Queue with independent
- * flow control. Several interfaces may be associated with a single TX Queue
- * if they belong to the same flow of traffic from the device. For multi-channel
- * operation there are independent TX Queues for each channel.
- */
-struct brcms_txq_info {
-	struct brcms_txq_info *next;
-	struct pktq q;
-	uint stopped;		/* tx flow control bits */
-};
-
 /*
  * Principal common driver data structure.
  *
@@ -432,11 +418,8 @@ struct brcms_txq_info {
  * WDlast: last time wlc_watchdog() was called.
  * edcf_txop[IEEE80211_NUM_ACS]: current txop for each ac.
  * wme_retries: per-AC retry limits.
- * tx_prec_map: Precedence map based on HW FIFO space.
- * fifo2prec_map[NFIFO]: pointer to fifo2_prec map based on WME.
  * bsscfg: set of BSS configurations, idx 0 is default and always valid.
  * cfg: the primary bsscfg (can be AP or STA).
- * tx_queues: common TX Queue list.
  * modulecb:
  * mimoft: SIGN or 11N.
  * cck_40txbw: 11N, cck tx b/w override when in 40MHZ mode.
@@ -466,7 +449,6 @@ struct brcms_txq_info {
  * tempsense_lasttime;
  * tx_duty_cycle_ofdm: maximum allowed duty cycle for OFDM.
  * tx_duty_cycle_cck: maximum allowed duty cycle for CCK.
- * pkt_queue: txq for transmit packets.
  * wiphy:
  * pri_scb: primary Station Control Block
  */
@@ -530,13 +512,9 @@ struct brcms_c_info {
 	u16 edcf_txop[IEEE80211_NUM_ACS];
 
 	u16 wme_retries[IEEE80211_NUM_ACS];
-	u16 tx_prec_map;
 
 	struct brcms_bss_cfg *bsscfg;
 
-	/* tx queue */
-	struct brcms_txq_info *tx_queues;
-
 	struct modulecb *modulecb;
 
 	u8 mimoft;
@@ -581,7 +559,6 @@ struct brcms_c_info {
 	u16 tx_duty_cycle_ofdm;
 	u16 tx_duty_cycle_cck;
 
-	struct brcms_txq_info *pkt_queue;
 	struct wiphy *wiphy;
 	struct scb pri_scb;
 };
@@ -633,11 +610,8 @@ struct brcms_bss_cfg {
 	struct brcms_bss_info *current_bss;
 };
 
-extern void brcms_c_txfifo(struct brcms_c_info *wlc, uint fifo,
-			   struct sk_buff *p, bool commit);
-extern void brcms_c_txfifo_complete(struct brcms_c_info *wlc, uint fifo);
-extern void brcms_c_txq_enq(struct brcms_c_info *wlc, struct scb *scb,
-			    struct sk_buff *sdu);
+extern int brcms_c_txfifo(struct brcms_c_info *wlc, uint fifo,
+			   struct sk_buff *p);
 extern void brcms_c_print_txstatus(struct tx_status *txs);
 extern int brcms_b_xmtfifo_sz_get(struct brcms_hardware *wlc_hw, uint fifo,
 		   uint *blocks);
@@ -652,9 +626,6 @@ static inline void brcms_c_print_txdesc(struct d11txh *txh)
 
 extern int brcms_c_set_gmode(struct brcms_c_info *wlc, u8 gmode, bool config);
 extern void brcms_c_mac_promisc(struct brcms_c_info *wlc, uint filter_flags);
-extern void brcms_c_send_q(struct brcms_c_info *wlc);
-extern int brcms_c_prep_pdu(struct brcms_c_info *wlc, struct sk_buff *pdu,
-			    uint *fifo);
 extern u16 brcms_c_calc_lsig_len(struct brcms_c_info *wlc, u32 ratespec,
 				uint mac_len);
 extern u32 brcms_c_rspec_to_rts_rspec(struct brcms_c_info *wlc,