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. Best Regards, Jose Miguel Abreu > > Thanks, > Bhadram.
