Merge patch series "net: migrate NO_NET out of the networking stack choice"

Quentin Schulz <[email protected]> says:

This migrates the net options away from the main Kconfig to net/Kconfig,
rename the current NET option to NET_LEGACY to really highlight what it
is and hopefully encourage more people to use lwIP, add a new NET
menuconfig (but keep NO_NET as an alias to NET=n for now) which then
allows us to replace all the "if legacy_stack || lwip_stack" checks with
"if net_support" which is easier to read and maintain.

The only doubt I have is wrt SYS_RX_ETH_BUFFER which seems to be needed
for now even when no network is configured? Likely due to
include/net-common.h with PKTBUFSRX?

No change in behavior is intended. Only change in defconfig including
other defconfigs where NO_NET=y or NET is not set, in which case NO_NET
is not set or NET=y should be set in the top defconfig. Similar change
required for config fragments. See commit log in patch adding NET
menuconfig for details.

This was tested based on 70fd0c3bb7c2 ("x86: there is no
CONFIG_UBOOT_ROMSIZE_KB_12288"), from within the GitLab CI container
trini/u-boot-gitlab-ci-runner:noble-20251013-23Jan2026 and set up
similarly as in "build all platforms in a single job" GitLab CI job.

 #!/usr/bin/env bash
 set -o pipefail
 set -eux

 ARGS="-BvelPEWM --reproducible-builds --step 0"
 ./tools/buildman/buildman -o ${O} --force-build $ARGS -CE $*
 ./tools/buildman/buildman -o ${O} $ARGS -Ssd $*

O=../build/u-boot/ ../u-boot.sh -b master^..b4/net-kconfig |& tee ../log.txt

I can't really decipher the log.txt, but there's no line starting with
+ which would be an error according to tools/buildman/builder.py help
text. Additionally, because I started the script with set -e set and
because buildman has an exit code != 0 when it fails to build a board,
and I have the summary printed (which is the second buildman call), I
believe it means all builds passed.

The summary is the following:
   aarch64: (for 537/537 boards) all +0.0 rodata +0.0
            uniphier_v8    : all +1 rodata +1
               u-boot: add: 0/0, grow: 1/0 bytes: 1/0 (1)
                 function                                   old     new   delta
                 data_gz                                  10640   10641      +1
       arm: (for 733/733 boards) all -0.0 rodata -0.0
            uniphier_v7    : all -1 rodata -1
               u-boot: add: 0/0, grow: 0/-1 bytes: 0/-1 (-1)
                 function                                   old     new   delta
                 data_gz                                  11919   11918      -1
            opos6uldev     : all -3 rodata -3
               u-boot: add: 0/0, grow: 0/-1 bytes: 0/-3 (-3)
                 function                                   old     new   delta
                 data_gz                                  18778   18775      -3
            uniphier_ld4_sld8: all -3 rodata -3
               u-boot: add: 0/0, grow: 0/-1 bytes: 0/-3 (-3)
                 function                                   old     new   delta
                 data_gz                                  11276   11273      -3
            stemmy         : all -20 rodata -20
               u-boot: add: 0/0, grow: 0/-1 bytes: 0/-20 (-20)
                 function                                   old     new   delta
                 data_gz                                  15783   15763     -20

As far as I could tell this data_gz is an automatically generated array
when CONFIG_CMD_CONFIG is enabled. It is the compressed .config stored
in binary form. Because I'm changing the name of symbols, replacing a
menu with a menuconfig, additional text makes it to .config and the
"# Networking" section in .config disappears.

Here is the diff for the 5 defconfigs listed above, generated with:

for f in build/*-m; do
	diff --unified=0 $f/.config $(dirname $f)/$(basename -a -s '-m' $f)/.config
done

(-m is the build directory for master, and without the suffix, it's the
top commit of this series)

"""
 --- build/opos6uldev-m/.config	2026-04-20 10:53:49.804528526 +0200
 +++ build/opos6uldev/.config	2026-04-20 11:03:37.430242767 +0200
 @@ -970,4 +969,0 @@
 -
 -#
 -# Networking
 -#
 @@ -975,0 +972 @@
 +CONFIG_NET_LEGACY=y
 --- build/stemmy-m/.config	2026-04-20 11:01:33.653698123 +0200
 +++ build/stemmy/.config	2026-04-20 11:04:53.452577311 +0200
 @@ -733,4 +732,0 @@
 -
 -#
 -# Networking
 -#
 @@ -738,2 +733,0 @@
 -# CONFIG_NET is not set
 -# CONFIG_NET_LWIP is not set
 --- build/uniphier_ld4_sld8-m/.config	2026-04-20 11:00:41.605469071 +0200
 +++ build/uniphier_ld4_sld8/.config	2026-04-20 11:04:22.226439899 +0200
 @@ -997,4 +996,0 @@
 -
 -#
 -# Networking
 -#
 @@ -1002,0 +999 @@
 +CONFIG_NET_LEGACY=y
 --- build/uniphier_v7-m/.config	2026-04-20 10:53:04.019307319 +0200
 +++ build/uniphier_v7/.config	2026-04-20 11:03:01.688085486 +0200
 @@ -1004,4 +1003,0 @@
 -
 -#
 -# Networking
 -#
 @@ -1009,0 +1006 @@
 +CONFIG_NET_LEGACY=y
 --- build/uniphier_v8-m/.config	2026-04-20 10:43:05.614441175 +0200
 +++ build/uniphier_v8/.config	2026-04-20 10:41:03.214852130 +0200
 @@ -875,4 +874,0 @@
 -
 -#
 -# Networking
 -#
 @@ -880,0 +877 @@
 +CONFIG_NET_LEGACY=y
"""

This is fine:
- Networking menu doesn't exist anymore so "#\n# Networking\n#\n" won't
  be in .config anymore.
- opos6uldev, uniphier_ld4_sld8, uniphier_v7 and uniphier_v8 all have
  (old) CONFIG_NET enabled, (new) CONFIG_NET will still be set but
  CONFIG_NET_LEGACY also needs to be defined now to reflect the stack
  choice (even if default),
- stemmy has CONFIG_NO_NET set, which means CONFIG_NET and
  CONFIG_NET_LWIP are not reachable anymore hence why they don't need to
  be part of .config,

GitLab CI was run on this series (well, not exactly, but it's only
changes to the git logs that were made):
https://source.denx.de/u-boot/contributors/qschulz/u-boot/-/pipelines/29849

It passes.

Link: https://lore.kernel.org/r/[email protected]

3 files changed, 7 insertions, 4 deletions

diff --git a/common/Kconfig b/common/Kconfig
index 2a167ec3ad3..8e8c733aa29 100644
--- a/common/Kconfig
+++ b/common/Kconfig
@@ -425,7 +425,7 @@ config LOGF_FUNC_PAD
 
 config LOG_SYSLOG
 	bool "Log output to syslog server"
-	depends on NET || NET_LWIP
+	depends on NET
 	help
 	  Enables a log driver which broadcasts log records via UDP port 514
 	  to syslog servers.
diff --git a/common/board_r.c b/common/board_r.c
index 5d37345ca09..ae686d18ae8 100644
--- a/common/board_r.c
+++ b/common/board_r.c
@@ -495,7 +495,7 @@ static int initr_boot_led_on(void)
 	return 0;
 }
 
-#if CONFIG_IS_ENABLED(NET) || CONFIG_IS_ENABLED(NET_LWIP)
+#if CONFIG_IS_ENABLED(NET)
 static int initr_net(void)
 {
 	puts("Net:   ");
@@ -760,7 +760,7 @@ static void initcall_run_r(void)
 #if CONFIG_IS_ENABLED(PCI_ENDPOINT)
 	INITCALL(pci_ep_init);
 #endif
-#if CONFIG_IS_ENABLED(NET) || CONFIG_IS_ENABLED(NET_LWIP)
+#if CONFIG_IS_ENABLED(NET)
 	WATCHDOG_RESET();
 	INITCALL(initr_net);
 #endif
diff --git a/common/spl/Kconfig b/common/spl/Kconfig
index a21b71ad5d1..5fa94098e49 100644
--- a/common/spl/Kconfig
+++ b/common/spl/Kconfig
@@ -1151,7 +1151,7 @@ config SPL_DM_SPI_FLASH
 
 config SPL_NET
 	bool "Support networking"
-	depends on NET
+	depends on NET_LEGACY
 	select SPL_USE_TINY_PRINTF_POINTER_SUPPORT if SPL_USE_TINY_PRINTF
 	help
 	  Enable support for network devices (such as Ethernet) in SPL.
@@ -1160,6 +1160,9 @@ config SPL_NET
 	  the network stack uses a number of environment variables. See also
 	  SPL_ETH.
 
+config SPL_NET_LEGACY
+	def_bool y if SPL_NET
+
 config SPL_NET_VCI_STRING
 	string "BOOTP Vendor Class Identifier string sent by SPL"
 	depends on SPL_NET