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. Thanks, Bhadram.
