On 28/11/16 18:33, Florian Fainelli wrote: > On 11/28/2016 02:38 AM, Sebastian Frias wrote: >> On 27/11/16 19:44, Florian Fainelli wrote: >>> Describe that the Ethernet MAC controller is ultimately responsible for >>> dealing with proper pause frames/flow control advertisement and >>> enabling, and that it is therefore allowed to have it change >>> phydev->supported/advertising with SUPPORTED_Pause and >>> SUPPORTED_AsymPause. >>> >>> Signed-off-by: Florian Fainelli <f.faine...@gmail.com> >>> --- >>> Documentation/networking/phy.txt | 18 ++++++++++++++++-- >>> 1 file changed, 16 insertions(+), 2 deletions(-) >>> >>> diff --git a/Documentation/networking/phy.txt >>> b/Documentation/networking/phy.txt >>> index 4b25c0f24201..9a42a9414cea 100644 >>> --- a/Documentation/networking/phy.txt >>> +++ b/Documentation/networking/phy.txt >>> @@ -127,8 +127,9 @@ Letting the PHY Abstraction Layer do Everything >>> values pruned from them which don't make sense for your controller (a >>> 10/100 >>> controller may be connected to a gigabit capable PHY, so you would need to >>> mask off SUPPORTED_1000baseT*). See include/linux/ethtool.h for >>> definitions >>> - for these bitfields. Note that you should not SET any bits, or the PHY may >>> - get put into an unsupported state. >>> + for these bitfields. Note that you should not SET any bits, except the >>> + SUPPORTED_Pause and SUPPORTED_AsymPause bits (see below), or the PHY may >>> get >>> + put into an unsupported state. >>> >>> Lastly, once the controller is ready to handle network traffic, you call >>> phy_start(phydev). This tells the PAL that you are ready, and configures >>> the >>> @@ -139,6 +140,19 @@ Letting the PHY Abstraction Layer do Everything >>> When you want to disconnect from the network (even if just briefly), you >>> call >>> phy_stop(phydev). >>> >>> +Pause frames / flow control >>> + >>> + The PHY does not participate directly in flow control/pause frames except >>> by >>> + making sure that the SUPPORTED_Pause and SUPPORTED_AsymPause bits are set >>> in >>> + MII_ADVERTISE to indicate towards the link partner that the Ethernet MAC >>> + controller supports such a thing. Since flow control/pause frames >>> generation >>> + involves the Ethernet MAC driver, it is recommended that this driver >>> takes care >>> + of properly indicating advertisement and support for such features by >>> setting >>> + the SUPPORTED_Pause and SUPPORTED_AsymPause bits accordingly. This can be >>> done >>> + either before or after phy_connect() >> >> If the bits are set after phy_connect(), how does the PHY framework knows >> there's >> an update to the bits? Should some call be made? > > You would most likely either call phy_start() to start the PHY state > machine (again) or have to re-negotiate the link with e.g: > genphy_restart_aneg(). >
Thanks, I think that would be worth adding to the documentation, right?
