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From: Christian Marangi <ansuelsmth@gmail.com>
To: Andrew Lunn <andrew@lunn.ch>,
	Heiner Kallweit <hkallweit1@gmail.com>,
	Russell King <linux@armlinux.org.uk>,
	"David S. Miller" <davem@davemloft.net>,
	Eric Dumazet <edumazet@google.com>,
	Jakub Kicinski <kuba@kernel.org>,
	Paolo Abeni <pabeni@redhat.com>,
	Christian Marangi <ansuelsmth@gmail.com>,
	Robert Marko <robimarko@gmail.com>,
	"Russell King (Oracle)" <rmk+kernel@armlinux.org.uk>,
	netdev@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: [net-next RFC PATCH 0/2] net: phy: aquantia: fix system interface provision
Date: Tue, 13 Feb 2024 19:24:10 +0100
Message-ID: <20240213182415.17223-1-ansuelsmth@gmail.com>
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Posting this as RFC as I think this require some discussion on the topic.

There is currently a problem. OEM multiple time provision Aquantia FW
with random and wrong data that may apply for one board but doesn't for
another. And at the same time OEM use the same broken FW for multiple
board and apply fixup at runtime.

This is the common case for AQR112 where downstream (uboot, OEM sdk,
openwrt to have the port correctly working) hack patch are used to fixup
broken system interface provision from the FW.

The downstream patch do one simple thing, they setup the SERDES startup
rate (that the FW may wrongly not init) and overwrite the
global system config for each rate to default values for the rwquested PHY
interface.

Now setting the SERDES startup value is SAFE, and this can be implemented
right away.

Overwriting the SERDES modes for each rate tho might pose some question
on how this is correct or wrong.

Reality is that probably every user an Aquantia PHY in one way or another
makes use of the SDK and have this patch in use making any kind of
provision on the FW ignored, (since the default values are always applied
at runtime) making the introduction of this change safe and restoring
correct functionality of AQR112 in the case of a broken FW loaded.

As said in the commit description, one thing this handle is the problem
where the FW is provision with 10BASE-R while the MAC supports and expect
UXSGMII.

The AQR PHY can correctly switch from one mode to another and I think it's
the most common case where one FW is broken.
This might be the safest change but again would not give us 100% idea that
the thing provision by the FW are correct.

Another idea might be adding a property like
"aquantia,broken-system-interface-provision" and with that enable we would
overwrite values with the default one.

Christian Marangi (2):
  net: phy: aquantia: setup interface protocols for AQR112
  net: phy: aquantia: add AQR112C and AQR112R PHY ID

 drivers/net/phy/aquantia/aquantia.h      |  17 +++
 drivers/net/phy/aquantia/aquantia_main.c | 152 +++++++++++++++++++++++
 2 files changed, 169 insertions(+)

-- 
2.43.0