net: phylink: add PHY_F_RXC_ALWAYS_ON to PHY dev flags

Browse source

Some MAC controllers (e.g. stmmac) require their connected PHY to
continuously provide a receive clock signal. This can cause issues in two
cases:

  1. The clock signal hasn't been started yet by the time the MAC driver
     initializes its hardware. This can make the initialization fail, as in
      the case of the rzn1 GMAC1 driver.
  2. The clock signal is cut during a power saving event. By the time the
     MAC is brought back up, the clock signal is still not active since
     phylink_start hasn't been called yet. This brings us back to case 1.

If a PHY driver reads this flag, it should ensure that the receive clock
signal is started as soon as possible, and that it isn't brought down when
the PHY goes into suspend.

Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
[rgantois: commit log]
Signed-off-by: Romain Gantois <romain.gantois@bootlin.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://lore.kernel.org/r/20240326-rxc_bugfix-v6-1-24a74e5c761f@bootlin.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

...

This commit is contained in:

Russell King (Oracle) 2024-03-26 14:32:07 +01:00 • committed by Jakub Kicinski

parent af352c3b66

commit 21d9ba5bc5

3 changed files with 14 additions and 1 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

10

drivers/net/phy/phylink.c

View file

1

include/linux/phy.h

View file

4

include/linux/phylink.h

View file