Natty: ath9k_hw: partially revert fix dma descriptor rx error bit parsing

[Seth Forshee]

On Mon, Apr 25, 2011 at 11:51:56AM -0600, Tim Gardner wrote:
> From 2b3494e8471c105708f0b69ae7ec2a97bafa6697 Mon Sep 17 00:00:00 2001
> From: Felix Fietkau <nbd at openwrt.org>
> Date: Fri, 14 Jan 2011 00:06:27 +0100
> Subject: [PATCH] (pre stable) ath9k_hw: partially revert "fix dma descriptor rx error bit parsing"
> 
> BugLink: http://bugs.launchpad.net/bugs/735171
> 
> The rx error bit parsing was changed to consider PHY errors and various
> decryption errors separately. While correct according to the documentation,
> this is causing spurious decryption error reports in some situations.
> 
> Fix this by restoring the original order of the checks in those places,
> where the errors are meant to be mutually exclusive.
> 
> If a CRC error is reported, then MIC failure and decryption errors
> are irrelevant, and a PHY error is unlikely.
> 
> Signed-off-by: Felix Fietkau <nbd at openwrt.org>
> Signed-off-by: John W. Linville <linville at tuxdriver.com>
> (cherry picked from commit 115dad7a7f42e68840392767323ceb9306dbdb36)
> 
> Signed-off-by: Tim Gardner <tim.gardner at canonical.com>

Acked-by: Seth Forshee <seth.forshee at canonical.com>

> ---
>  drivers/net/wireless/ath/ath9k/ar9003_mac.c |    8 ++++----
>  drivers/net/wireless/ath/ath9k/mac.c        |   14 ++++++++++----
>  2 files changed, 14 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/net/wireless/ath/ath9k/ar9003_mac.c b/drivers/net/wireless/ath/ath9k/ar9003_mac.c
> index 4ceddbb..038a0cb 100644
> --- a/drivers/net/wireless/ath/ath9k/ar9003_mac.c
> +++ b/drivers/net/wireless/ath/ath9k/ar9003_mac.c
> @@ -615,7 +615,7 @@ int ath9k_hw_process_rxdesc_edma(struct ath_hw *ah, struct ath_rx_status *rxs,
>  		 */
>  		if (rxsp->status11 & AR_CRCErr)
>  			rxs->rs_status |= ATH9K_RXERR_CRC;
> -		if (rxsp->status11 & AR_PHYErr) {
> +		else if (rxsp->status11 & AR_PHYErr) {
>  			phyerr = MS(rxsp->status11, AR_PHYErrCode);
>  			/*
>  			 * If we reach a point here where AR_PostDelimCRCErr is
> @@ -638,11 +638,11 @@ int ath9k_hw_process_rxdesc_edma(struct ath_hw *ah, struct ath_rx_status *rxs,
>  				rxs->rs_phyerr = phyerr;
>  			}
>  
> -		}
> -		if (rxsp->status11 & AR_DecryptCRCErr)
> +		} else if (rxsp->status11 & AR_DecryptCRCErr)
>  			rxs->rs_status |= ATH9K_RXERR_DECRYPT;
> -		if (rxsp->status11 & AR_MichaelErr)
> +		else if (rxsp->status11 & AR_MichaelErr)
>  			rxs->rs_status |= ATH9K_RXERR_MIC;
> +
>  		if (rxsp->status11 & AR_KeyMiss)
>  			rxs->rs_status |= ATH9K_RXERR_DECRYPT;
>  	}
> diff --git a/drivers/net/wireless/ath/ath9k/mac.c b/drivers/net/wireless/ath/ath9k/mac.c
> index 2915b11..5efc869 100644
> --- a/drivers/net/wireless/ath/ath9k/mac.c
> +++ b/drivers/net/wireless/ath/ath9k/mac.c
> @@ -690,17 +690,23 @@ int ath9k_hw_rxprocdesc(struct ath_hw *ah, struct ath_desc *ds,
>  		rs->rs_flags |= ATH9K_RX_DECRYPT_BUSY;
>  
>  	if ((ads.ds_rxstatus8 & AR_RxFrameOK) == 0) {
> +		/*
> +		 * Treat these errors as mutually exclusive to avoid spurious
> +		 * extra error reports from the hardware. If a CRC error is
> +		 * reported, then decryption and MIC errors are irrelevant,
> +		 * the frame is going to be dropped either way
> +		 */
>  		if (ads.ds_rxstatus8 & AR_CRCErr)
>  			rs->rs_status |= ATH9K_RXERR_CRC;
> -		if (ads.ds_rxstatus8 & AR_PHYErr) {
> +		else if (ads.ds_rxstatus8 & AR_PHYErr) {
>  			rs->rs_status |= ATH9K_RXERR_PHY;
>  			phyerr = MS(ads.ds_rxstatus8, AR_PHYErrCode);
>  			rs->rs_phyerr = phyerr;
> -		}
> -		if (ads.ds_rxstatus8 & AR_DecryptCRCErr)
> +		} else if (ads.ds_rxstatus8 & AR_DecryptCRCErr)
>  			rs->rs_status |= ATH9K_RXERR_DECRYPT;
> -		if (ads.ds_rxstatus8 & AR_MichaelErr)
> +		else if (ads.ds_rxstatus8 & AR_MichaelErr)
>  			rs->rs_status |= ATH9K_RXERR_MIC;
> +
>  		if (ads.ds_rxstatus8 & AR_KeyMiss)
>  			rs->rs_status |= ATH9K_RXERR_DECRYPT;
>  	}
> -- 
> 1.7.0.4
> 
> 
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