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b=2BoqeVo8b/r8r1kU2jB8tm4ELNpBxJ99sx3bypmBhmJ6ghMbqUNHDuKrghv7ecwYhC/tH9YL7XnYyiVsSFX4W3i/EtzNhomIXJkMA/cQtlQqgAJzJsaL327vpdg3WHbIbbs4oM6gbcfHFmcN3zj9dMfw7lQ5Ctp0+URlEQ2RMrg= Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=amd.com; Received: from SN7PR12MB8147.namprd12.prod.outlook.com (2603:10b6:806:32e::5) by MN0PR12MB5809.namprd12.prod.outlook.com (2603:10b6:208:375::7) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9769.6; Thu, 26 Mar 2026 10:12:00 +0000 Received: from SN7PR12MB8147.namprd12.prod.outlook.com ([fe80::3923:c1a4:778b:56f2]) by SN7PR12MB8147.namprd12.prod.outlook.com ([fe80::3923:c1a4:778b:56f2%3]) with mapi id 15.20.9769.006; Thu, 26 Mar 2026 10:12:00 +0000 Message-ID: <57b046e7-79ca-4d3c-952d-1cb9439601c1@amd.com> Date: Thu, 26 Mar 2026 15:41:51 +0530 User-Agent: Mozilla Thunderbird Subject: Re: [RFC PATCH 0/8] xilinx: tsn: Add TSN Endpoint Ethernet MAC driver support From: "Neeli, Srinivas" To: Andrew Lunn , "Neeli, Srinivas" Cc: "andrew+netdev@lunn.ch" , "davem@davemloft.net" , "edumazet@google.com" , "kuba@kernel.org" , "pabeni@redhat.com" , "Simek, Michal" , "robh@kernel.org" , "krzk+dt@kernel.org" , "conor+dt@kernel.org" , "richardcochran@gmail.com" , "netdev@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "devicetree@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "git (AMD-Xilinx)" References: <20260219054911.2017362-1-srinivas.neeli@amd.com> <5f884e29-151a-4ee7-9e1a-d7e1f84d9f6c@lunn.ch> <28b232f1-5814-4b3a-af28-1eab023743c0@lunn.ch> Content-Language: en-US In-Reply-To: Content-Type: text/plain; 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Is there an extra header >>>> on the frame sent by EndPoint, which the switch interprets? >>>> >>> In this RFC, I configured all switch ports in forward mode. As a >>> result, when a frame is sent from the internal endpoint, it is >>> flooded to both external ports.  To forward packets to a specific >>> port instead of flooding, either static switch CAM entries need to >>> be configured or address learning should be enabled so the switch >>> can learn CAM entries dynamically. >> Despite not being part of AMD, this part is important. >> >> I don't care about how the RFC works, i want to know how the hardware >> works, to ensure you have the correct choice of DSA vs pure switchdev. >> >> Take the example of running Spanning Tree Protocol. The bridge needs >> to send the BPDU out a specific port. What mechanism is used to do >> that? It also needs to know which port a BPDU ingressed. >> >>     Andrew > > > Hi Andrew, > > I would like to briefly share an overview of our TSN switch > capabilities and seek your guidance on the most appropriate Linux > framework for the driver implementation specifically whether switchdev > or DSA would be the better fit. > > TSN Switch Capabilities > ----------------------- > Our TSN subsystem supports the following IEEE TSN clauses: > > IEEE 802.1Qbv – Time-Aware Shaper (scheduled traffic using gate control) > IEEE 802.1Qbu / IEEE 802.3br – Frame preemption > IEEE 802.1Qci – Per-Stream Filtering and Policing (PSFP), including: > SDU-based filtering and Meter-based policing > IEEE 802.1CB – Frame Replication and Elimination for Reliability (FRER) > IEEE 802.1AS / IEEE 1588 – Time synchronization (PTP / gPTP) > > Hardware Architecture Overview > ------------------------------ > The switch consists of three ports: > > Port 0: Connected to the CPU (control/endpoint port) > Port 1: Connected to MAC1 > Port 2: Connected to MAC2 > > MAC1 and MAC2 are capable of transmitting and receiving PTP packets, > with received packets stored in internal BRAM. They will not be > forwarded by switch to the internal endpoint (EP) and MAC network > drivers xmit's and receives the PTP frames. > The switch forwards frames based on VLAN port membership and the CAM > entries and switch supports TSN features such as CBS, Qci (PSFP) and > 802.1CB (FRER) through hardware configuration. > The CPU is intended to operate purely in the control plane and is not > part of the forwarding data path. > > Thank you very much for your time and guidance. Please let us know if > any additional details would be helpful. > > > Best regards, > Neeli Srinivas > Hi Andrew, Based on the feedback so far, I am planning to proceed with a switchdev based implementation for the next RFC series, as this appears to be a better fit with the Linux networking model. Please let me know if you have any concerns with this approach. If this direction is acceptable, I will share the next version of the RFC series accordingly. Thank you for your guidance. Best regards, Neeli Srinivas