On 10/18/2017 12:09 PM, Andrew Lunn wrote:
>> Yes, but with the caveat already covered today: there is a possible
>> problem with having to divert MDIO accesses of a PHY pointed by
>> phy-handle towards the internal switch bus because of specific problems
>> such as those explained in drivers/net/bcm_sf2.c, I don't mind trying to
>> do things smarter or in a different way, but that needs to be something
>> possible.
>
> Hi Florian
>
> Are you referring to:
>
> /* Include the pseudo-PHY address to divert reads towards our
> * workaround. This is only required for 7445D0, since 7445E0
> * disconnects the internal switch pseudo-PHY such that we can use the
> * regular SWITCH_MDIO master controller instead.
> *
> * Here we flag the pseudo PHY as needing special treatment and would
> * otherwise make all other PHY read/writes go to the master MDIO bus
> * controller that comes with this switch backed by the "mdio-unimac"
> * driver.
> */
> ?
Yes.
>
> Do you have an example device tree fragment, just to make it clearer?
Sure:
switch_top@f0b00000 {
compatible = "simple-bus";
#size-cells = <1>;
#address-cells = <1>;
ranges = <0 0xf0b00000 0x40804>;
ethernet_switch@0 {
compatible = "brcm,bcm7445-switch-v4.0";
#size-cells = <0>;
#address-cells = <1>;
reg = <0x0 0x40000
0x40000 0x110
0x40340 0x30
0x40380 0x30
0x40400 0x34
0x40600 0x208>;
reg-names = "core", "reg", intrl2_0", "intrl2_1",
"fcb, "acb";
interrupts = <0 0x18 0
0 0x19 0>;
brcm,num-gphy = <1>;
brcm,num-rgmii-ports = <2>;
brcm,fcb-pause-override;
brcm,acb-packets-inflight;
ports {
#address-cells = <1>;
#size-cells = <0>;
port@0 {
label = "gphy";
reg = <0>;
phy-handle = <&phy5>;
};
port@1 {
label = "rgmii_1";
reg = <1>;
/* connects to the external BCM53125 switch
below */
fixed-link {
speed = <1000>;
full-duplex;
}
};
};
};
mdio@403c0 {
reg = <0x403c0 0x8 0x40300 0x18>;
#address-cells = <0x1>;
#size-cells = <0x0>;
compatible = "brcm,bcm7445-mdio-v4.0", "brcm,unimac-mdio";
reg-names = "mdio", "mdio_indir_rw";
phy5: ethernet-phy@5 {
reg = <0x5>;
compatible = "brcm,28nm-gphy",
"ethernet-phy-ieee802.3-c22";
};
/* External BCM53125 switch that requires the workaround above
*/
ethernet-switch@0 {
reg = <0>;
compatible = "brcm,bcm53125";
ports {
...
};
};
};
In fact, this now makes me think that I had to put this workaround in
place solely because at some point I modeled the external BCM53125
switch as a PHY device, and so I had to have phy_connect() work correctly!
Now that we have a proper MDIO device class, this may actually no longer
be necessary at all within net/dsa/slave.c::dsa_slave_phy_setup() since
the probe paths would work completely differently and the offending port
(port 1) would have a fixed-link property. I still need my local
workaround in bcm_sf2.c of course.
I guess, thanks for making me post this example and realize this is
probably no longer necessary :)
--
Florian
