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The list of ports which support SGMII depending on switch generation is
available here:
https://www.kernel.org/doc/html/latest/networking/dsa/sja1105.html#port-compatibility-matrix
SGMII can either be used to connect to an external PHY or to the host
port. In the first case, the use of in-band autoneg is expected, in the
last, in-band autoneg is expected to be turned off (fixed-link). So the
driver supports both cases.
SGMII support means configuring the PCS and PMA. The PCS is a Synopsys
Designware XPCS, in Linux this has a separate driver but here it is
embedded within the sja1105 driver. If needed it can be taken out later,
although we would need a UCLASS_PCS for it, which we don't have atm.
Nonetheless, I did go all the way to export an internal MDIO bus for PCS
access, because it is nice to be able to debug the PCS through commands
such as:
=> mdio read ethernet-switch@1-pcs 4 1f.0
Reading from bus ethernet-switch@1-pcs
PHY at address 4:
31.0 - 0x1140
The internal MDIO bus is not registered with DM because there is no
udevice on it, as mentioned. But the XPCS code can still be ripped out,
as needed.
I did not add support for 2500base-x because I do not expect this
interface type to be used as a boot source for anybody, it would just
add unnecessary bloat.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Ramon Fried <rfried.dev@gmail.com>
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The SJA1105 driver is largely reused from Linux. Its programming model
is that it is blank out of reset, and it waits for a static
configuration stream over SPI, which contains all runtime parameters (it
has no notion of "default values").
Keeping a binary array for the configuration stream would have meant
that aspects such as the CPU port and the MAC speeds could have not been
configured easily, and would have been static and board-dependent.
Live-patching the binary array means recalculating the static config
table CRCs, which is not a fun process.
So we create an abstraction over the static config tables, using the
packing API, same as in Linux. The tables are kept as C structures, and
the binary configuration stream is constructed on-the-go, with CRC and
all.
All static config tables instantiated in this driver are mandatory.
The hardware reference manual can be found at:
https://www.nxp.com/docs/en/user-guide/UM10944.pdf
For tagging, a simplified version of tag_8021q from Linux is used. The
VLAN EtherType is the same (0xdadb) but since we don't want switching in
U-Boot, there is no reason to have a TX VLAN and an RX VLAN for each
port. We just need the RX VLANs to act as the unique pvid of each
front-panel port, to decode the switch port number. The RX VLAN is used
for both RX and TX.
The device tree bindings are the same as in Linux.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Ramon Fried <rfried.dev@gmail.com>
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