Subject: Re: linux-next-20170320 breaks stmmac on meson (Amlogic S905GXBB)

From: Corentin Labbe <[email-masked]>
Date: Tue, 21 Mar 2017 15:07:31 +0100

On Tue, Mar 21, 2017 at 10:13:08AM +0000, Joao Pinto wrote:
> 
> Hi Heiner and Corentin,
> 
> Às 9:58 PM de 3/20/2017, Heiner Kallweit escreveu:
> > As reported by Corentin Labbe before:
> > stmmac in the latest next kernel is broken also on meson8b.
> > 
> > The following commit seems to create the trouble:
> > 6deee2221e11 "net: stmmac: prepare dma op mode config for multiple queues"
> > 
> > I also get queue timeout errors.
> 
> From what you are describing it seems that the tx op mode is not being
> configured by some reason and so it is not enabled.
> 
> Please check if this path is being executed:
> 
> stmmac_mtl_configuration >> stmmac_dma_operation_mode >> priv->hw->dma->dma_tx_mode
> 
> It must iterate by all the available channels / queues, that should be =1 since
> I assume you have a single queue:
> 
> 	if (priv->synopsys_id >= DWMAC_CORE_4_00) {
> 		for (chan = 0; chan < rx_channels_count; chan++)
> 			priv->hw->dma->dma_rx_mode(priv->ioaddr, rxmode, chan,
> 						   rxfifosz);
> 
> 		for (chan = 0; chan < tx_channels_count; chan++)
> 			priv->hw->dma->dma_tx_mode(priv->ioaddr, txmode, chan);
> 
> Could you please check if RX and TX op mode are being programmed?
> 
> The rx and tx queue counters are initialized in stmmac_mtl_setup() function
> (stmmac_platform.c). If they are not declared in DT they assume the default
> value of 1.
> 

Since stmmac_mtl_configuration is only called with priv->synopsys_id >= DWMAC_CORE_4_00, all older platform never call stmmac_dma_operation_mode.

Re-adding stmmac_dma_operation_mode at its place before 6deee2221e110f6574988120dba6cab7e7313f44 "net: stmmac: prepare dma op mode config for multiple queues" fix my issue.