Re: [PATCH net-next 5/7] net: phy: marvell10g: Force reading of 2.5/5G PMA extended abilities
From: Maxime Chevallier <maxime.chevallier@bootlin.com>
Date: 2019-01-21 12:30:00
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Hello Russell, On Mon, 21 Jan 2019 10:52:06 +0000 Russell King - ARM Linux admin [off-list ref] wrote:
On Mon, Jan 21, 2019 at 11:35:31AM +0100, Maxime Chevallier wrote:quoted
Hello Andrew, On Sun, 20 Jan 2019 20:08:09 +0100 Andrew Lunn [off-list ref] wrote:quoted
On Fri, Jan 18, 2019 at 04:23:50PM +0100, Maxime Chevallier wrote:quoted
As per 802.3bz, if bit 14 of (1.11) "PMA Extended Abilities" indicates whether or not we should read register (1.21) "2.52/5G PMA Extended Abilities", which contains information on the support of 2.5GBASET and 5GBASET. After testing on several variants of PHYS of this family, it appears that bit 14 in (1.11) isn't always set when it should be. PHYs 88X3310 (on MacchiatoBin) and 88E2010 do support 2.5G and 5GBASET, but don't have 1.11.14 set. Their register 1.21 is filled with the correct values, indicating 2.5G and 5G support. PHYs 88X2110 do have their 1.11.14 bit set, as it should.Hi Maxime Is there anything about this in any Errata?I haven't seen any Errata on that unfortunately. I also thought about reading (1.4) "PMA/PMD Speed Ability", but the 2.5G and 5G speeds are also reported as not being supported on the 88X3310.It's entirely possible that the 3310 switches to different hardware blocks for 2.5G and 5G speeds, and reading _just_ the 1.4 register is not sufficient.
I agree with you but in that particular case, I think we are reading from the correct device. The datasheet itself says that we should be reading 1.4 and 1.11 as we expect, with 2.5G/5G support being set (these registers are read-only, and the datasheet's values aren't what we actually read).
The 88x3310 is multiple PHY devices in one package, with a CPU that manages the routing between each individual device.
I also just checked register 3.4 "PCS Speed Ability", and 3.8 "PCS Status 2" which also contains informations on 2.5G/5G abilities, but there's the same issue here. Maxime -- Maxime Chevallier, Bootlin Embedded Linux and kernel engineering https://bootlin.com