Re: [PATCH v2 06/22] brcmsmac: Remove internal tx queue

["Arend van Spriel" <arend@broadcom.com>]

On 11/15/2012 03:07 PM, Seth Forshee wrote:
> 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.

Reviewed-by: Pieter-Paul Giesberts <pieterpg@broadcom.com>
Reviewed-by: Arend van Spriel <arend@broadcom.com>
> Signed-off-by: Seth Forshee <seth.forshee@canonical.com>
> ---
>   drivers/net/wireless/brcm80211/brcmsmac/ampdu.c |  167 +--------
>   drivers/net/wireless/brcm80211/brcmsmac/ampdu.h |    3 -
>   drivers/net/wireless/brcm80211/brcmsmac/dma.c   |  189 ++++++++--
>   drivers/net/wireless/brcm80211/brcmsmac/dma.h   |    9 +-
>   drivers/net/wireless/brcm80211/brcmsmac/main.c  |  459 ++++++++---------------
>   drivers/net/wireless/brcm80211/brcmsmac/main.h  |   33 +-
>   drivers/net/wireless/brcm80211/brcmsmac/pub.h   |   13 -
>   drivers/net/wireless/brcm80211/brcmsmac/types.h |    1 -
>   8 files changed, 316 insertions(+), 558 deletions(-)
>
> diff --git a/drivers/net/wireless/brcm80211/brcmsmac/main.c b/drivers/net/wireless/brcm80211/brcmsmac/main.c
> index 8abf39d..2b8987c 100644
> --- a/drivers/net/wireless/brcm80211/brcmsmac/main.c
> +++ b/drivers/net/wireless/brcm80211/brcmsmac/main.c
> @@ -303,6 +304,18 @@ static const u8 wme_ac2fifo[] = {
>   	TX_AC_BK_FIFO
>   };
>
> +/* 802.1D Priority to precedence queue mapping */
> +const u8 wlc_prio2prec_map[] = {
> +	_BRCMS_PREC_BE,		/* 0 BE - Best-effort */
> +	_BRCMS_PREC_BK,		/* 1 BK - Background */
> +	_BRCMS_PREC_NONE,		/* 2 None = - */
> +	_BRCMS_PREC_EE,		/* 3 EE - Excellent-effort */
> +	_BRCMS_PREC_CL,		/* 4 CL - Controlled Load */
> +	_BRCMS_PREC_VI,		/* 5 Vi - Video */
> +	_BRCMS_PREC_VO,		/* 6 Vo - Voice */
> +	_BRCMS_PREC_NC,		/* 7 NC - Network Control */
> +};
> +

The wlc_prio2prec_map was removed in patch 06/22. Some reordering of 
commits gone wrong here?

>   static const u16 xmtfifo_sz[][NFIFO] = {
>   	/* corerev 17: 5120, 49152, 49152, 5376, 4352, 1280 */
>   	{20, 192, 192, 21, 17, 5},