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, 6 insertions, 3 deletions

diff --git a/drivers/net/wireless/brcm80211/brcmsmac/dma.h b/drivers/net/wireless/brcm80211/brcmsmac/dma.h
index cc269ee5c499..459abf13924a 100644
--- a/drivers/net/wireless/brcm80211/brcmsmac/dma.h
+++ b/drivers/net/wireless/brcm80211/brcmsmac/dma.h
@@ -74,8 +74,7 @@ struct dma_pub {
 	uint txnobuf;		/* tx out of dma descriptors */
 };
 
-extern struct dma_pub *dma_attach(char *name, struct si_pub *sih,
-				  struct bcma_device *d11core,
+extern struct dma_pub *dma_attach(char *name, struct brcms_c_info *wlc,
 				  uint txregbase, uint rxregbase,
 				  uint ntxd, uint nrxd,
 				  uint rxbufsize, int rxextheadroom,
@@ -87,7 +86,11 @@ bool dma_rxfill(struct dma_pub *pub);
 bool dma_rxreset(struct dma_pub *pub);
 bool dma_txreset(struct dma_pub *pub);
 void dma_txinit(struct dma_pub *pub);
-int dma_txfast(struct dma_pub *pub, struct sk_buff *p0, bool commit);
+int dma_txfast(struct brcms_c_info *wlc, struct dma_pub *pub,
+	       struct sk_buff *p0);
+void dma_txflush(struct dma_pub *pub);
+int dma_txpending(struct dma_pub *pub);
+void dma_kick_tx(struct dma_pub *pub);
 void dma_txsuspend(struct dma_pub *pub);
 bool dma_txsuspended(struct dma_pub *pub);
 void dma_txresume(struct dma_pub *pub);