[PATCH net-next 0/2] net: stmmac: only use MAC loopback for selftests

[Maxime Chevallier <maxime.chevallier@bootlin.com>]

stmmac selftests currently use PHY loopback when a PHY is attached, and
fallback to MAC loopback otherwise. PHY loopback however isn't ideal nor
necessary for the tests we are running, that only stress the internal
stmmac features.

Some PHYs bring the carrier state down when in loopback mode, which will
prevent any packet transmission even for ourselves, making selftests
fail for non-stmmac related reasons.

Let's rely only on MAC-side loopback for selftests, making it clear that
any problem found with stmmac selftests are indeed caused by the stmmac
driver, and not external factors.

This was tested on :

 - Cyclone V with RGMII link to KSZ9031
 - Cyclone V with 1000BaseX
 - imx8mp with RGMII link to KSZ9131
 - stm32mp157& with RGMII link to RTL8211F
 - Allwinner H2+ with an internal PHY

Maxime Chevallier (2):
  net: stmmac: Don't use PHY loopback for selftests
  net: stmmac: Don't rely on the PHY for flow-control testing

 .../stmicro/stmmac/stmmac_selftests.c         | 117 ++----------------
 1 file changed, 11 insertions(+), 106 deletions(-)

-- 
2.55.0