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* [PATCH] TI DaVinci EMAC: Clear statistics register properly.
@ 2009-10-07 12:44 Sriramakrishnan
       [not found] ` <1254919470-20595-1-git-send-email-srk-l0cyMroinI0@public.gmane.org>
  0 siblings, 1 reply; 2+ messages in thread
From: Sriramakrishnan @ 2009-10-07 12:44 UTC (permalink / raw)
  To: netdev-u79uwXL29TY76Z2rM5mHXA
  Cc: srk-l0cyMroinI0,
	davinci-linux-open-source-VycZQUHpC/PFrsHnngEfi1aTQe2KTcn/

The mechanism to clear the statistics register is dependent
on the status of GMIIEN bit in MAC control register. If the
GMIIEN bit is set, the stats registers are write to decrement.
If the GMIIEN bit is cleared, the stats registers are plain
read/write registers. The stats register clearing operation
must take into account the current state of GMIIEN as it
can be cleared when the interface is brought down.

With existing implementation logic, querying for interface stats
when the interface is down, can corrupt the statistics counters.
This patch examines the GMIIEN bit status in MAC_CONTROL
register before choosing an appropriate mask for clearing stats
registers.

Signed-off-by: Sriramakrishnan <srk-l0cyMroinI0@public.gmane.org>
Acked-by: Chaithrika U S <chaithrika-l0cyMroinI0@public.gmane.org>
---
This patch is generated against the tip of net-next-2.6.

 drivers/net/davinci_emac.c |   36 ++++++++++++++++++++++++------------
 1 files changed, 24 insertions(+), 12 deletions(-)

diff --git a/drivers/net/davinci_emac.c b/drivers/net/davinci_emac.c
index a421ec0..a876dce 100644
--- a/drivers/net/davinci_emac.c
+++ b/drivers/net/davinci_emac.c
@@ -330,6 +330,9 @@ static const char emac_version_string[] = "TI DaVinci EMAC Linux v6.1";
 #define EMAC_DM646X_MAC_EOI_C0_RXEN	(0x01)
 #define EMAC_DM646X_MAC_EOI_C0_TXEN	(0x02)
 
+/* EMAC Stats Clear Mask */
+#define EMAC_STATS_CLR_MASK    (0xFFFFFFFF)
+
 /** net_buf_obj: EMAC network bufferdata structure
  *
  * EMAC network buffer data structure
@@ -2544,40 +2547,49 @@ static int emac_dev_stop(struct net_device *ndev)
 static struct net_device_stats *emac_dev_getnetstats(struct net_device *ndev)
 {
 	struct emac_priv *priv = netdev_priv(ndev);
+	u32 mac_control;
+	u32 stats_clear_mask;
 
 	/* update emac hardware stats and reset the registers*/
 
+	mac_control = emac_read(EMAC_MACCONTROL);
+
+	if (mac_control & EMAC_MACCONTROL_GMIIEN)
+		stats_clear_mask = EMAC_STATS_CLR_MASK;
+	else
+		stats_clear_mask = 0;
+
 	priv->net_dev_stats.multicast += emac_read(EMAC_RXMCASTFRAMES);
-	emac_write(EMAC_RXMCASTFRAMES, EMAC_ALL_MULTI_REG_VALUE);
+	emac_write(EMAC_RXMCASTFRAMES, stats_clear_mask);
 
 	priv->net_dev_stats.collisions += (emac_read(EMAC_TXCOLLISION) +
 					   emac_read(EMAC_TXSINGLECOLL) +
 					   emac_read(EMAC_TXMULTICOLL));
-	emac_write(EMAC_TXCOLLISION, EMAC_ALL_MULTI_REG_VALUE);
-	emac_write(EMAC_TXSINGLECOLL, EMAC_ALL_MULTI_REG_VALUE);
-	emac_write(EMAC_TXMULTICOLL, EMAC_ALL_MULTI_REG_VALUE);
+	emac_write(EMAC_TXCOLLISION, stats_clear_mask);
+	emac_write(EMAC_TXSINGLECOLL, stats_clear_mask);
+	emac_write(EMAC_TXMULTICOLL, stats_clear_mask);
 
 	priv->net_dev_stats.rx_length_errors += (emac_read(EMAC_RXOVERSIZED) +
 						emac_read(EMAC_RXJABBER) +
 						emac_read(EMAC_RXUNDERSIZED));
-	emac_write(EMAC_RXOVERSIZED, EMAC_ALL_MULTI_REG_VALUE);
-	emac_write(EMAC_RXJABBER, EMAC_ALL_MULTI_REG_VALUE);
-	emac_write(EMAC_RXUNDERSIZED, EMAC_ALL_MULTI_REG_VALUE);
+	emac_write(EMAC_RXOVERSIZED, stats_clear_mask);
+	emac_write(EMAC_RXJABBER, stats_clear_mask);
+	emac_write(EMAC_RXUNDERSIZED, stats_clear_mask);
 
 	priv->net_dev_stats.rx_over_errors += (emac_read(EMAC_RXSOFOVERRUNS) +
 					       emac_read(EMAC_RXMOFOVERRUNS));
-	emac_write(EMAC_RXSOFOVERRUNS, EMAC_ALL_MULTI_REG_VALUE);
-	emac_write(EMAC_RXMOFOVERRUNS, EMAC_ALL_MULTI_REG_VALUE);
+	emac_write(EMAC_RXSOFOVERRUNS, stats_clear_mask);
+	emac_write(EMAC_RXMOFOVERRUNS, stats_clear_mask);
 
 	priv->net_dev_stats.rx_fifo_errors += emac_read(EMAC_RXDMAOVERRUNS);
-	emac_write(EMAC_RXDMAOVERRUNS, EMAC_ALL_MULTI_REG_VALUE);
+	emac_write(EMAC_RXDMAOVERRUNS, stats_clear_mask);
 
 	priv->net_dev_stats.tx_carrier_errors +=
 		emac_read(EMAC_TXCARRIERSENSE);
-	emac_write(EMAC_TXCARRIERSENSE, EMAC_ALL_MULTI_REG_VALUE);
+	emac_write(EMAC_TXCARRIERSENSE, stats_clear_mask);
 
 	priv->net_dev_stats.tx_fifo_errors = emac_read(EMAC_TXUNDERRUN);
-	emac_write(EMAC_TXUNDERRUN, EMAC_ALL_MULTI_REG_VALUE);
+	emac_write(EMAC_TXUNDERRUN, stats_clear_mask);
 
 	return &priv->net_dev_stats;
 }
-- 
1.6.2.4

^ permalink raw reply related	[flat|nested] 2+ messages in thread
* Re: [PATCH] TI DaVinci EMAC: Clear statistics register properly.
       [not found] ` <1254919470-20595-1-git-send-email-srk-l0cyMroinI0@public.gmane.org>
@ 2009-10-08 19:11   ` Kevin Hilman
  0 siblings, 0 replies; 2+ messages in thread
From: Kevin Hilman @ 2009-10-08 19:11 UTC (permalink / raw)
  To: Sriramakrishnan
  Cc: netdev-u79uwXL29TY76Z2rM5mHXA,
	davinci-linux-open-source-VycZQUHpC/PFrsHnngEfi1aTQe2KTcn/

Sriramakrishnan <srk-l0cyMroinI0@public.gmane.org> writes:

> The mechanism to clear the statistics register is dependent
> on the status of GMIIEN bit in MAC control register. If the
> GMIIEN bit is set, the stats registers are write to decrement.
> If the GMIIEN bit is cleared, the stats registers are plain
> read/write registers. The stats register clearing operation
> must take into account the current state of GMIIEN as it
> can be cleared when the interface is brought down.
>
> With existing implementation logic, querying for interface stats
> when the interface is down, can corrupt the statistics counters.
> This patch examines the GMIIEN bit status in MAC_CONTROL
> register before choosing an appropriate mask for clearing stats
> registers.
>
> Signed-off-by: Sriramakrishnan <srk-l0cyMroinI0@public.gmane.org>
> Acked-by: Chaithrika U S <chaithrika-l0cyMroinI0@public.gmane.org>
> ---
> This patch is generated against the tip of net-next-2.6.

OK, will also add to linux-davinci while waiting for it reach
mainline.

Kevin

>  drivers/net/davinci_emac.c |   36 ++++++++++++++++++++++++------------
>  1 files changed, 24 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/net/davinci_emac.c b/drivers/net/davinci_emac.c
> index a421ec0..a876dce 100644
> --- a/drivers/net/davinci_emac.c
> +++ b/drivers/net/davinci_emac.c
> @@ -330,6 +330,9 @@ static const char emac_version_string[] = "TI DaVinci EMAC Linux v6.1";
>  #define EMAC_DM646X_MAC_EOI_C0_RXEN	(0x01)
>  #define EMAC_DM646X_MAC_EOI_C0_TXEN	(0x02)
>  
> +/* EMAC Stats Clear Mask */
> +#define EMAC_STATS_CLR_MASK    (0xFFFFFFFF)
> +
>  /** net_buf_obj: EMAC network bufferdata structure
>   *
>   * EMAC network buffer data structure
> @@ -2544,40 +2547,49 @@ static int emac_dev_stop(struct net_device *ndev)
>  static struct net_device_stats *emac_dev_getnetstats(struct net_device *ndev)
>  {
>  	struct emac_priv *priv = netdev_priv(ndev);
> +	u32 mac_control;
> +	u32 stats_clear_mask;
>  
>  	/* update emac hardware stats and reset the registers*/
>  
> +	mac_control = emac_read(EMAC_MACCONTROL);
> +
> +	if (mac_control & EMAC_MACCONTROL_GMIIEN)
> +		stats_clear_mask = EMAC_STATS_CLR_MASK;
> +	else
> +		stats_clear_mask = 0;
> +
>  	priv->net_dev_stats.multicast += emac_read(EMAC_RXMCASTFRAMES);
> -	emac_write(EMAC_RXMCASTFRAMES, EMAC_ALL_MULTI_REG_VALUE);
> +	emac_write(EMAC_RXMCASTFRAMES, stats_clear_mask);
>  
>  	priv->net_dev_stats.collisions += (emac_read(EMAC_TXCOLLISION) +
>  					   emac_read(EMAC_TXSINGLECOLL) +
>  					   emac_read(EMAC_TXMULTICOLL));
> -	emac_write(EMAC_TXCOLLISION, EMAC_ALL_MULTI_REG_VALUE);
> -	emac_write(EMAC_TXSINGLECOLL, EMAC_ALL_MULTI_REG_VALUE);
> -	emac_write(EMAC_TXMULTICOLL, EMAC_ALL_MULTI_REG_VALUE);
> +	emac_write(EMAC_TXCOLLISION, stats_clear_mask);
> +	emac_write(EMAC_TXSINGLECOLL, stats_clear_mask);
> +	emac_write(EMAC_TXMULTICOLL, stats_clear_mask);
>  
>  	priv->net_dev_stats.rx_length_errors += (emac_read(EMAC_RXOVERSIZED) +
>  						emac_read(EMAC_RXJABBER) +
>  						emac_read(EMAC_RXUNDERSIZED));
> -	emac_write(EMAC_RXOVERSIZED, EMAC_ALL_MULTI_REG_VALUE);
> -	emac_write(EMAC_RXJABBER, EMAC_ALL_MULTI_REG_VALUE);
> -	emac_write(EMAC_RXUNDERSIZED, EMAC_ALL_MULTI_REG_VALUE);
> +	emac_write(EMAC_RXOVERSIZED, stats_clear_mask);
> +	emac_write(EMAC_RXJABBER, stats_clear_mask);
> +	emac_write(EMAC_RXUNDERSIZED, stats_clear_mask);
>  
>  	priv->net_dev_stats.rx_over_errors += (emac_read(EMAC_RXSOFOVERRUNS) +
>  					       emac_read(EMAC_RXMOFOVERRUNS));
> -	emac_write(EMAC_RXSOFOVERRUNS, EMAC_ALL_MULTI_REG_VALUE);
> -	emac_write(EMAC_RXMOFOVERRUNS, EMAC_ALL_MULTI_REG_VALUE);
> +	emac_write(EMAC_RXSOFOVERRUNS, stats_clear_mask);
> +	emac_write(EMAC_RXMOFOVERRUNS, stats_clear_mask);
>  
>  	priv->net_dev_stats.rx_fifo_errors += emac_read(EMAC_RXDMAOVERRUNS);
> -	emac_write(EMAC_RXDMAOVERRUNS, EMAC_ALL_MULTI_REG_VALUE);
> +	emac_write(EMAC_RXDMAOVERRUNS, stats_clear_mask);
>  
>  	priv->net_dev_stats.tx_carrier_errors +=
>  		emac_read(EMAC_TXCARRIERSENSE);
> -	emac_write(EMAC_TXCARRIERSENSE, EMAC_ALL_MULTI_REG_VALUE);
> +	emac_write(EMAC_TXCARRIERSENSE, stats_clear_mask);
>  
>  	priv->net_dev_stats.tx_fifo_errors = emac_read(EMAC_TXUNDERRUN);
> -	emac_write(EMAC_TXUNDERRUN, EMAC_ALL_MULTI_REG_VALUE);
> +	emac_write(EMAC_TXUNDERRUN, stats_clear_mask);
>  
>  	return &priv->net_dev_stats;
>  }
> -- 
> 1.6.2.4
>
> _______________________________________________
> Davinci-linux-open-source mailing list
> Davinci-linux-open-source-VycZQUHpC/PFrsHnngEfi1aTQe2KTcn/@public.gmane.org
> http://linux.davincidsp.com/mailman/listinfo/davinci-linux-open-source

^ permalink raw reply	[flat|nested] 2+ messages in thread
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2009-10-07 12:44 [PATCH] TI DaVinci EMAC: Clear statistics register properly Sriramakrishnan
     [not found] ` <1254919470-20595-1-git-send-email-srk-l0cyMroinI0@public.gmane.org>
2009-10-08 19:11   ` Kevin Hilman

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