Re: [PATCH net-next] net: dsa: bcm_sf2: Ensure that MDIO diversion is used
On Thu, Sep 03, 2020 at 09:00:13PM -0700, Florian Fainelli wrote: > > > On 9/3/2020 3:03 PM, Andrew Lunn wrote: > > > The firmware provides the Device Tree but here is the relevant section for > > > you pasted below. The problematic device is a particular revision of the > > > silicon (D0) which got later fixed (E0) however the Device Tree was > > > created > > > after the fixed platform, not the problematic one. Both revisions of the > > > silicon are in production. > > > > > > There should have been an internal MDIO bus created for that chip revision > > > such that we could have correctly parented phy@0 (bcm53125 below) as child > > > node of the internal MDIO bus, but you have to realize that this was done > > > back in 2014 when DSA was barely revived as an active subsystem. The > > > BCM53125 node should have have been converted to an actual switch node at > > > some point, I use a mdio_boardinfo overlay downstream to support the > > > switch > > > as a proper b53/DSA switch, anyway. > > > > I was expecting something like that. I think this patch needs a > > comment in the code explaining it is a workaround for a DT blob which > > cannot be changed. Maybe also make it conditional on the board > > compatible string? > > It is already targeted at the Broadcom pseudo PHY address (30) which is the > one that needs diversion, I will update the patch description accordingly > though. O.K, looking at the patch, it was not clear to me it was already restricted. Andrew
Re: [PATCH net-next] net: dsa: bcm_sf2: Ensure that MDIO diversion is used
On 9/3/2020 3:03 PM, Andrew Lunn wrote: The firmware provides the Device Tree but here is the relevant section for you pasted below. The problematic device is a particular revision of the silicon (D0) which got later fixed (E0) however the Device Tree was created after the fixed platform, not the problematic one. Both revisions of the silicon are in production. There should have been an internal MDIO bus created for that chip revision such that we could have correctly parented phy@0 (bcm53125 below) as child node of the internal MDIO bus, but you have to realize that this was done back in 2014 when DSA was barely revived as an active subsystem. The BCM53125 node should have have been converted to an actual switch node at some point, I use a mdio_boardinfo overlay downstream to support the switch as a proper b53/DSA switch, anyway. I was expecting something like that. I think this patch needs a comment in the code explaining it is a workaround for a DT blob which cannot be changed. Maybe also make it conditional on the board compatible string? It is already targeted at the Broadcom pseudo PHY address (30) which is the one that needs diversion, I will update the patch description accordingly though. -- Florian
Re: [PATCH net-next] net: dsa: bcm_sf2: Ensure that MDIO diversion is used
> The firmware provides the Device Tree but here is the relevant section for > you pasted below. The problematic device is a particular revision of the > silicon (D0) which got later fixed (E0) however the Device Tree was created > after the fixed platform, not the problematic one. Both revisions of the > silicon are in production. > > There should have been an internal MDIO bus created for that chip revision > such that we could have correctly parented phy@0 (bcm53125 below) as child > node of the internal MDIO bus, but you have to realize that this was done > back in 2014 when DSA was barely revived as an active subsystem. The > BCM53125 node should have have been converted to an actual switch node at > some point, I use a mdio_boardinfo overlay downstream to support the switch > as a proper b53/DSA switch, anyway. I was expecting something like that. I think this patch needs a comment in the code explaining it is a workaround for a DT blob which cannot be changed. Maybe also make it conditional on the board compatible string? Thanks Andrew
Re: [PATCH net-next] net: dsa: bcm_sf2: Ensure that MDIO diversion is used
On 9/2/2020 6:13 PM, Andrew Lunn wrote:
On Wed, Sep 02, 2020 at 02:03:27PM -0700, Florian Fainelli wrote:
Registering our slave MDIO bus outside of the OF infrastructure is
necessary in order to avoid creating double references of the same
Device Tree nodes, however it is not sufficient to guarantee that the
MDIO bus diversion is used because of_phy_connect() will still resolve
to a valid PHY phandle and it will connect to the PHY using its parent
MDIO bus which is still the SF2 master MDIO bus.
Ensure that of_phy_connect() does not suceed by removing any phandle
reference for the PHY we need to divert. This forces the DSA code to use
the DSA slave_mii_bus that we register and ensures the MDIO diversion is
being used.
Hi Florian
Sorry, i don't get this explanation. Can you point me towards a device
tree i can look at to maybe understand what is going on.
The firmware provides the Device Tree but here is the relevant section
for you pasted below. The problematic device is a particular revision of
the silicon (D0) which got later fixed (E0) however the Device Tree was
created after the fixed platform, not the problematic one. Both
revisions of the silicon are in production.
There should have been an internal MDIO bus created for that chip
revision such that we could have correctly parented phy@0 (bcm53125
below) as child node of the internal MDIO bus, but you have to realize
that this was done back in 2014 when DSA was barely revived as an active
subsystem. The BCM53125 node should have have been converted to an
actual switch node at some point, I use a mdio_boardinfo overlay
downstream to support the switch as a proper b53/DSA switch, anyway.
The problem is that of_phy_connect() for port@1 will resolve the
phy-handle from the mdio@403c0 node, which bypasses the diversion
completely. This results in this double programming that the diversion
refers to. In order to force of_phy_connect() to fail, and have DSA call
to dsa_slave_phy_connect(), we must deactivate ethernet-phy@0 from
mdio@403c0, and the best way to do that is by removing the phandle
property completely.
Hope this clarifies the mess :)
switch_top@f0b0 {
#address-cells = <0x01>;
#size-cells = <0x01>;
compatible = "brcm,bcm7445-switch-top-v2.0\0simple-bus";
ranges = <0x00 0xf0b0 0x40804>;
ethernet_switch@0 {
#address-cells = <0x02>;
#size-cells = <0x00>;
brcm,num-acb-queues = <0x40>;
brcm,num-gphy = <0x01>;
brcm,num-rgmii-ports = <0x02>;
compatible =
"brcm,bcm7445-switch-v4.0\0brcm,bcm53012";
dsa,ethernet = <0x16>;
dsa,mii-bus = <0x17>;
resets = <0x18 0x1a>;
reset-names = "switch";
reg = <0x00 0x4 0x4 0x110 0x40340 0x30 0x40380 0x30 0x40400
0x34 0x40600 0x208>;
reg-names =
"core\0reg\0intrl2_0\0intrl2_1\0fcb\0acb";
interrupts = <0x00 0x18 0x04 0x00 0x19 0x04>;
interrupt-names = "switch_0\0switch_1";
brcm,fcb-pause-override;
brcm,acb-packets-inflight;
clocks = <0x0a 0x6d 0x0a 0x76>;
clock-names = "sw_switch\0sw_switch_mdiv";
ports {
#address-cells = <0x01>;
#size-cells = <0x00>;
port@0 {
phy-mode = "internal";
phy-handle = <0x29>;
linux,phandle = <0x2a>;
phandle = <0x2a>;
reg = <0x00>;
label = "gphy";
};
port@1 {
phy-mode = "rgmii-txid";
phy-handle = <0x2c>;
linux,phandle = <0x2d>;
phandle = <0x2d>;
reg = <0x01>;
label = "rgmii_1";
};
port@2 {
phy-mode = "rgmii-txid";
Re: [PATCH net-next] net: dsa: bcm_sf2: Ensure that MDIO diversion is used
On Wed, Sep 02, 2020 at 02:03:27PM -0700, Florian Fainelli wrote: > Registering our slave MDIO bus outside of the OF infrastructure is > necessary in order to avoid creating double references of the same > Device Tree nodes, however it is not sufficient to guarantee that the > MDIO bus diversion is used because of_phy_connect() will still resolve > to a valid PHY phandle and it will connect to the PHY using its parent > MDIO bus which is still the SF2 master MDIO bus. > > Ensure that of_phy_connect() does not suceed by removing any phandle > reference for the PHY we need to divert. This forces the DSA code to use > the DSA slave_mii_bus that we register and ensures the MDIO diversion is > being used. Hi Florian Sorry, i don't get this explanation. Can you point me towards a device tree i can look at to maybe understand what is going on. Andrew
Re: [PATCH net-next] net: dsa: bcm_sf2: Ensure that MDIO diversion is used
Hi Florian, I love your patch! Yet something to improve: [auto build test ERROR on net-next/master] url: https://github.com/0day-ci/linux/commits/Florian-Fainelli/net-dsa-bcm_sf2-Ensure-that-MDIO-diversion-is-used/20200903-050536 base: https://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next.git dc1a9bf2c8169d9f607502162af1858a73a18cb8 config: sh-allmodconfig (attached as .config) compiler: sh4-linux-gcc (GCC) 9.3.0 reproduce (this is a W=1 build): wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=sh If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot All errors (new ones prefixed by >>, old ones prefixed by <<): >> ERROR: modpost: "of_remove_property" [drivers/net/dsa/bcm-sf2.ko] undefined! ERROR: modpost: "__delay" [drivers/net/mdio/mdio-cavium.ko] undefined! --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-...@lists.01.org .config.gz Description: application/gzip
