Re: [PATCH] can: ti_hecc: fix rx wrong sequence issue

[Marc Kleine-Budde <mkl@pengutronix.de>]

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On 11/05/2012 02:47 PM, AnilKumar, Chimata wrote:
> On Mon, Nov 05, 2012 at 17:04:55, Marc Kleine-Budde wrote:
>> Hello,
> 
> Hi Marc,
> 
> Thanks for looking into this issue, I had spent some considerable
> time for debugging this issue, I have seen better sequence with
> below changes at 500KBPS but issue still there. Because of some
> other higher priority task I left there.

I'm testing with cansequence at 500 kbit/s at the moment. With my
current patch, I'm not seeing any out-of-order problem. With "ping -f"
and serial load, the driver goes into a rx-overflow. But this is
probably due to too high load.

The hardware I'm using has an issue with 1Mbit/s, thus I cannot test this.

> Some of my observations in the driver:-
> 1. One is buffer mailbox (12th mailbox we are missing)
> 
> @@ -627,18 +617,34 @@ static int ti_hecc_rx_poll(struct napi_struct *napi, int quota)
>  			if (ti_hecc_rx_pkt(priv, priv->rx_next) < 0)
>  				return num_pkts;
>  			++num_pkts;
> -		} else if (priv->rx_next > HECC_RX_BUFFER_MBOX) {
> +		} else if (priv->rx_next >= HECC_RX_BUFFER_MBOX) {
>  			break; /* pkt not received yet */
>  		}
>  		--priv->rx_next;
> -		if (priv->rx_next == HECC_RX_BUFFER_MBOX) {
> -			/* enable high bank mailboxes */
> -			spin_lock_irqsave(&priv->mbx_lock, flags);
> +		if (priv->rx_next == (HECC_RX_BUFFER_MBOX - 1)) {
> 
> 2. Lower mail box configuration is not happening properly. I have
> changed this.
> 3. Removed spinlocks (Just for testing)

I've reworked the poll-loop completely.

[...]

> I can test the series if your patches are ready.

I'll send you a preliminary version to test soon, it wouldn't be finial,
but you can test, also include 1Mbit/s.

Marc

-- 
Pengutronix e.K.                  | Marc Kleine-Budde           |
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