On 26-10-2017 15:44, Bhadram Varka wrote: > Hi Jose, > >> -----Original Message----- >> From: Jose Abreu [mailto:jose.ab...@synopsys.com] >> Sent: Thursday, October 26, 2017 5:19 PM >> To: Bhadram Varka <vbhad...@nvidia.com>; netdev@vger.kernel.org; >> linux-ker...@vger.kernel.org >> Cc: Joao Pinto <joao.pi...@synopsys.com>; David S. Miller >> <da...@davemloft.net>; Giuseppe Cavallaro <peppe.cavall...@st.com>; >> Alexandre Torgue <alexandre.tor...@st.com> >> Subject: Re: [PATCH net] net: stmmac: First Queue must always be in DCB >> mode >> >> Hi Bhadram, >> >> On 26-10-2017 11:51, Bhadram Varka wrote: >>> Hi Jose, >>> >>>> -----Original Message----- >>>> From: netdev-ow...@vger.kernel.org [mailto:netdev- >>>> ow...@vger.kernel.org] On Behalf Of Jose Abreu >>>> Sent: Thursday, October 26, 2017 2:37 PM >>>> To: netdev@vger.kernel.org; linux-ker...@vger.kernel.org >>>> Cc: Jose Abreu <jose.ab...@synopsys.com>; Joao Pinto >>>> <joao.pi...@synopsys.com>; David S. Miller <da...@davemloft.net>; >>>> Giuseppe Cavallaro <peppe.cavall...@st.com>; Alexandre Torgue >>>> <alexandre.tor...@st.com> >>>> Subject: [PATCH net] net: stmmac: First Queue must always be in DCB >>>> mode >>>> >>>> According to DWMAC databook the first queue operating mode must >>>> always be in DCB. >>>> >>>> As MTL_QUEUE_DCB = 1, we need to always set the first queue operating >>>> mode to DCB otherwise driver will think that queue is in AVB mode >>>> (because MTL_QUEUE_AVB = 0). >>>> >>>> Signed-off-by: Jose Abreu <joab...@synopsys.com> >>>> Cc: Joao Pinto <jpi...@synopsys.com> >>>> Cc: David S. Miller <da...@davemloft.net> >>>> Cc: Giuseppe Cavallaro <peppe.cavall...@st.com> >>>> Cc: Alexandre Torgue <alexandre.tor...@st.com> >>>> --- >>>> drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c | 7 +++++++ >>>> 1 file changed, 7 insertions(+) >>>> >>>> diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c >>>> b/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c >>>> index 21f59fe..603225b 100644 >>>> --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c >>>> +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c >>>> @@ -150,6 +150,13 @@ static void stmmac_mtl_setup(struct >>>> platform_device *pdev, >>>> plat->rx_queues_to_use = 1; >>>> plat->tx_queues_to_use = 1; >>>> >>>> + /* First Queue must always be in DCB mode. As MTL_QUEUE_DCB = >>>> 1 we need >>>> + * to always set this, otherwise Queue will be classified as AVB >>>> + * (because MTL_QUEUE_AVB = 0). >>>> + */ >>> Its better if we can check whether IP HW features (register - 0x120) >> supports the DCB or not. If yes, then set the DCB mode. >>> There is possibility that DCB feature not enable for few of the Synopsys >> IP's. >> >> A queue can either be in Generic/DCB or AVB mode. The sequence to enable >> a DCB or a Generic queue is the same so there is no need to check for DCB >> capability in HW. > Point is that we don't have DCB enabled for the IP. > > From your point it will work in Generic (legacy) mode if we set DCB filed. If > this is the understanding then we are fine.
Yes, thats true. Generic and DCB have the same configuration. Best Regards, Jose Miguel Abreu > > Thanks, > Bhadram.
