> -----Original Message----- > From: Ferruh Yigit <ferruh.yi...@intel.com> > Sent: Thursday, September 23, 2021 3:40 PM > To: Apeksha Gupta <apeksha.gu...@nxp.com>; > david.march...@redhat.com; andrew.rybche...@oktetlabs.ru; > ferruh.yi...@intel.com > Cc: dev@dpdk.org; Sachin Saxena <sachin.sax...@nxp.com>; Hemant > Agrawal <hemant.agra...@nxp.com> > Subject: [EXT] Re: [dpdk-dev] [PATCH v3 1/5] net/enetfec: introduce NXP > ENETFEC driver > > Caution: EXT Email > > On 9/9/2021 9:43 PM, Apeksha Gupta wrote: > > ENETFEC (Fast Ethernet Controller) is a network poll mode driver > > for NXP SoC i.MX 8M Mini. > > > > Hi Apeksha, > > Before going into details, I have some high level comments to start with, > please > find comments below. > > > This patch adds skeleton for enetfec driver with probe function. > > > > Signed-off-by: Sachin Saxena <sachin.sax...@nxp.com> > > Signed-off-by: Apeksha Gupta <apeksha.gu...@nxp.com> > > <...> > > > +++ b/doc/guides/nics/enetfec.rst > > @@ -0,0 +1,122 @@ > > +.. SPDX-License-Identifier: BSD-3-Clause > > + Copyright 2021 NXP > > + > > +ENETFEC Poll Mode Driver > > +======================== > > + > > +The ENETFEC NIC PMD (**librte_net_enetfec**) provides poll mode > driver > > +support for the inbuilt NIC found in the ** NXP i.MX 8M Mini** SoC. > > + > > +More information can be found at NXP Official Website > > > +<https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fw > ww.nxp.com%2Fproducts%2Fprocessors-and-microcontrollers%2Farm- > processors%2Fi-mx-applications-processors%2Fi-mx-8-processors%2Fi-mx- > 8m-mini-arm-cortex-a53-cortex-m4-audio-voice- > video%3Ai.MX8MMINI&data=04%7C01%7Capeksha.gupta%40nxp.com > %7C74fdc59c47574d828f7608d97e7a4df3%7C686ea1d3bc2b4c6fa92cd99c5c30 > 1635%7C0%7C1%7C637679886024819097%7CUnknown%7CTWFpbGZsb3d8ey > JWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D% > 7C3000&sdata=TjuqIfC8yXwBa3DLCgA7djItfV0UmZ6lA3uLDQ7TFwY%3D > &reserved=0> > > + > > +ENETFEC > > +------- > > + > > +This section provides an overview of the NXP ENETFEC and how it is > > +integrated into the DPDK. > > + > > +Contents summary > > + > > +- ENETFEC overview > > +- ENETFEC features > > +- Supported ENETFEC SoCs > > +- Prerequisites > > +- Driver compilation and testing > > +- Limitations > > + > > +ENETFEC Overview > > +~~~~~~~~~~~~~~~~ > > +The i.MX 8M Mini Media Applications Processor is built to achieve both > high > > +performance and low power consumption. ENETFEC is a hardware > programmable > > +packet forwarding engine to provide high performance Ethernet interface. > > It has 1Gbps interface, right? It can be good to give more details on the > Ethernet interface. [Apeksha] Okay. > > > +The diagram below shows a system level overview of ENETFEC: > > + > > + > ====================================================+===== > ========== > > + US +-----------------------------------------+ | Kernel Space > > + | | | > > + | ENETFEC Driver | | > > + +-----------------------------------------+ | > > + ^ | | > > + ENETFEC RXQ | | TXQ | > > + PMD | | | > > + | v | +----------+ > > + +-------------+ | | fec-uio | > > + | net_enetfec | | +----------+ > > + +-------------+ | > > + ^ | | > > + TXQ | | RXQ | > > + | | | > > + | v | > > + > ===================================================+====== > ========= > > + +----------------------------------------+ > > + | | HW > > + | i.MX 8M MINI EVK | > > + | +-----+ | > > + | | MAC | | > > + +---------------+-----+------------------+ > > + | PHY | > > + +-----+ > > + > > +ENETFEC Ethernet driver is traditional DPDK PMD driver running in the > userspace. > > +The MAC and PHY are the hardware blocks. 'fec-uio' is the UIO driver, > ENETFEC PMD > > +uses UIO interface to interact with kernel for PHY initialisation and for > mapping > > +the allocated memory of register & BD in kernel with DPDK which gives > access to > > +non-cacheable memory for BD. > > Why a specific uio driver, 'fec-uio', is required? I think this is the major > issue to clarify to proceed. > > In DPDK we have full framework to support uio, to do the all memory > mapping, > interrupt configuration etc..., common to all drivers. > But in this case driver is implemented as virtual driver and it handles its > own > uoi handling itself. Why the driver can't use existing support and > implemented > as physical driver? [Apeksha] Yes you are correct. As per our knowledge, UIO framework is there for VM & PCI bus devices and not for vdev bus devices. That is why we are using standard UIO framework in DPDK to access with kernel 'fec-uio' driver. In document description I will update the details more precisely.
> > btw, what is 'BD'? [Apeksha] BD is Buffer Descriptor. we will update it in v4 patch series. > > > net_enetfec is logical Ethernet interface, created by > > +ENETFEC driver. > > + > > It is confusing to draw 'net_enetfec' as middle man between HW and driver, > isn't > it same entity as driver? Why the Rx/Tx notation is reverse before and after > net_enetfec, as HW --TX--> net_enetfec --RX--> driver? [Apeksha] yes I do agree. We will update the figure in v4 patch series. > > > +- ENETFEC driver registers the device in virtual device driver. > > +- RTE framework scans and will invoke the probe function of ENETFEC > driver. > > +- The probe function will set the basic device registers and also setups BD > rings. > > +- On packet Rx the respective BD Ring status bit is set which is then used > for > > + packet processing. > > +- Then Tx is done first followed by Rx via logical interfaces. > > + > > +ENETFEC Features > > +~~~~~~~~~~~~~~~~~ > > + > > +- Linux > > +- ARMv8 > > + > > +Supported ENETFEC SoCs > > +~~~~~~~~~~~~~~~~~~~~~~ > > + > > +- i.MX 8M Mini > > + > > +Prerequisites > > +~~~~~~~~~~~~~ > > + > > +There are three main pre-requisites for executing ENETFEC PMD on a i.MX > 8M Mini > > +compatible board: > > + > > +1. **ARM 64 Tool Chain** > > + > > + For example, the `*aarch64* Linaro Toolchain > <https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Frele > ases.linaro.org%2Fcomponents%2Ftoolchain%2Fbinaries%2F7.4- > 2019.02%2Faarch64-linux-gnu%2Fgcc-linaro-7.4.1-2019.02-x86_64_aarch64- > linux- > gnu.tar.xz&data=04%7C01%7Capeksha.gupta%40nxp.com%7C74fdc59c > 47574d828f7608d97e7a4df3%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7 > C1%7C637679886024819097%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4w > LjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&am > p;sdata=Lun43hJqB%2Fw%2Bd07v9hOn3NrsRdlmeyoesiRrJLt81p8%3D& > reserved=0>`_. > > + > > +2. **Linux Kernel** > > + > > + It can be obtained from `NXP's Github hosting > <https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fsour > ce.codeaurora.org%2Fexternal%2Fqoriq%2Fqoriq- > components%2Flinux&data=04%7C01%7Capeksha.gupta%40nxp.com% > 7C74fdc59c47574d828f7608d97e7a4df3%7C686ea1d3bc2b4c6fa92cd99c5c3016 > 35%7C0%7C1%7C637679886024819097%7CUnknown%7CTWFpbGZsb3d8eyJ > WIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D% > 7C3000&sdata=0EFI%2ByEZB1PvYGt%2BemrLA2poBMdgPFTti9S7CO0qP > X4%3D&reserved=0>`_. > > + > > There are multiple branches in that repo, is there more detail on which > branch > to use? [Apeksha] lf-5.10.y branch, will add it in v4 patch series. > > > +3. **Rootfile system** > > + > > + Any *aarch64* supporting filesystem can be used. For example, > > + Ubuntu 18.04 LTS (Bionic) or 20.04 LTS(Focal) userland which can be > obtained > > + from `here > <https://eur01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fcdim > age.ubuntu.com%2Fubuntu- > base%2Freleases%2F18.04%2Frelease%2Fubuntu-base-18.04.1-base- > arm64.tar.gz&data=04%7C01%7Capeksha.gupta%40nxp.com%7C74fdc5 > 9c47574d828f7608d97e7a4df3%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0 > %7C1%7C637679886024819097%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC > 4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000& > amp;sdata=18AItEAX8Yp6bsyDdrGmVCu%2BQ9%2FJroX%2BS9CadeKsS%2Bw > %3D&reserved=0>`_. > > + > > +4. The Ethernet device will be registered as virtual device, so ENETFEC has > dependency on > > + **rte_bus_vdev** library and it is mandatory to use `--vdev` with value > `net_enetfec` to > > + run DPDK application. > > + > > +Driver compilation and testing > > +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > + > > +Follow instructions available in the document > > +:ref:`compiling and testing a PMD for a NIC <pmd_build_and_test>` > > +to launch **dpdk-testpmd** > > + > > +Limitations > > +~~~~~~~~~~~ > > + > > +- Multi queue is not supported. > > +- Link status is down always. > > This seems a big limitation, it can prevents some application to use the NIC. > What prevents the having proper link status? [Apeksha] I agree this is a bug. 'link change status' support is planned to be implemented in future. Meanwhile we will set link default status to UP so all other applications work seamlessly. > > > +- Single Ethernet interface. > > What does 'Single Ethernet interface' means, can you please elaborate? [Apeksha] Your observation is correct, this is mistake from our side. This is hardware feature i.e. only one Ethernet interface available on i.MX 8M Mini. We realize that this is not a limitation. We will update it. > > <...> > > > + > > +#define ENETFEC_NAME_PMD net_enetfec > > +#define ENETFEC_VDEV_GEM_ID_ARG "intf" > > Is this devarg used at all? [Apeksha] No, I will update in v4 patch series. > > <...> > > > +/* Common log type name prefix */ > > +#define ENETFEC_LOGTYPE_PREFIX "pmd.net.enetfec." > > + > > Is this macro used at all? [Apeksha] No, I will update in v4 patch series. > > <...> > > > +# SPDX-License-Identifier: BSD-3-Clause > > +# Copyright 2021 NXP > > + > > +if not is_linux > > + build = false > > + reason = 'only supported on linux' > > +endif > > + > > +deps += ['common_dpaax'] > > + > > Why there is a dependency to dpaax? [Apeksha] There was some common MACROs that we are using & are part of dpaax (drivers/common/dpaax/compat.h). As per suggestion we will remove this dependency in v4 patch series.
