Hi Maxim, On Wed, 2 Aug 2023 at 08:09, Maxim Uvarov <maxim.uva...@linaro.org> wrote: > > Just add inital doc. > > Signed-off-by: Maxim Uvarov <maxim.uva...@linaro.org> > --- > doc/develop/index.rst | 1 + > doc/develop/net_lwip.rst | 55 ++++++++++++++++++++++++++++++++++++++++ > 2 files changed, 56 insertions(+) > create mode 100644 doc/develop/net_lwip.rst >
Reviewed-by: Simon Glass <s...@chromium.org> > diff --git a/doc/develop/index.rst b/doc/develop/index.rst > index ddbf8dad4a..f8ab6cb56e 100644 > --- a/doc/develop/index.rst > +++ b/doc/develop/index.rst > @@ -46,6 +46,7 @@ Implementation > smbios > spl > uefi/index > + net_lwip > vbe > version > > diff --git a/doc/develop/net_lwip.rst b/doc/develop/net_lwip.rst > new file mode 100644 > index 0000000000..784b8f960c > --- /dev/null > +++ b/doc/develop/net_lwip.rst > @@ -0,0 +1,55 @@ > +.. SPDX-License-Identifier: GPL-2.0+ > + > +LWIP IP stack intergation for U-Boot spelling > +==================================== > + > +Intro > +----- > + > +LWIP is a library implementating network protocols, which is commonly used spelling > +on embedded devices. > + > +https://savannah.nongnu.org/projects/lwip/ > + > +LwIP license: > +LwIP is licensed under a BSD-style license: > http://lwip.wikia.com/wiki/License. > + > +Main features include: > + > +* Protocols: IP, IPv6, ICMP, ND, MLD, UDP, TCP, IGMP, ARP, PPPoS, PPPoE > + > +* DHCP client, DNS client (incl. mDNS hostname resolver), AutoIP/APIPA > (Zeroconf), SNMP agent (v1, v2c, v3, private MIB support & MIB compiler) > + > +* APIs: specialized APIs for enhanced performance, optional Berkeley-alike > socket API > + > +* Extended features: IP forwarding over multiple network interfaces, TCP > congestion control, RTT estimation and fast recovery/fast retransmit Can we stick to 80cois for docs? > + > +* Addon applications: HTTP(S) server, SNTP client, SMTP(S) client, ping, > NetBIOS nameserver, mDNS responder, MQTT client, TFTP server > + > +U-Boot implementation details > +----------------------------- > + > +1. In general we can build lwIP as .a library and link it against u-boot or > compile it in as a U-Boot (please check throughout) > +the U-Boot tree in the same way as other U-Boot files. There are few reasons > why I selected > +the second variant: LwIP is very customizable with defines for features, > memory size, types of > +allocation, some internal types and platform specific code. It turned out > easier to enable/disable > +debug which is also done with defines, and is needed periodically. > + > +2. lwIP has 2 APIs - raw mode and sequential (as lwIP names it, or socket > API as we name it in Linux). > +For now only raw API is supported. > + > +In raw IP mode a callback function for RX path is registered and will be > called when packet > +is passed to the IP stack and is ready for the application. > + > +Example is unmodified working ping example from lwip sources which > registeres the callback: spelling > + > +.. code-block:: c > + > + ping_pcb = raw_new(IP_PROTO_ICMP); > + raw_recv(ping_pcb, ping_recv, NULL); <- ping_recv is app callback. > + raw_bind(ping_pcb, IP_ADDR_ANY) > + > +3. Input and output > + > +RX packet path is injected to U-Boot eth_rx() polling loop and TX patch is > in eth_send() accordingly. > +So we do not touch any drivers code and just eat packets when they are ready. > -- > 2.30.2 > Regards, Simon
