DP83865 ethernet phy used on DRA74x-evm is quirky and the datasheet
provided IODELAY values for standard RGMII phys do not work.
Silicon Revision(SR) 2.0 provides an alternative bit configuration
that allows us to do a "gross adjustment" to launch the data off a
different internal clock edge. Manual IO Delay overrides are still
necessary to fine tune the clock-to-data delays. This is a necessary
workaround for the quirky ethernet Phy we have on the platform.
NOTE: SMA registers are spare "kitchen sink" registers that does
contain bits for other workaround as necessary as well. Hence the
control for the same is introduced in a generic SoC specific, board
generic location.
Signed-off-by: Nishanth Menon <nm@ti.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
In addition to the regular mux configuration, certain pins of DRA7
require to have "manual mode" also programmed, when predefined
delay characteristics cannot be used for the interface.
struct iodelay_cfg_entry is introduced for populating
manual mode IO timings.
For configuring manual mode, along with the normal pad
configuration do the following steps:
- Select MODESELECT field of each assocaited PAD.
CTRL_CORE_PAD_XXX[8]:MODESELECT = 1(Enable MANUAL_MODE macro along with mux)
- Populate A_DELAY, G_DELAY values that are specified in DATA MANUAL.
And pass the offset of the CFG_XXX register in iodelay_cfg_entry.
Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>
Signed-off-by: Nishanth Menon <nm@ti.com>
On DRA7, in addition to the regular muxing of pins, an additional
hardware module called IODelay which is also expected to be
configured. This "IODelay" module has it's own register space that is
independent of the control module.
It is advocated strongly in TI's official documentation considering
the existing design of the DRA7 family of processors during mux or
IODelay recalibration, there is a potential for a significant glitch
which may cause functional impairment to certain hardware. It is
hence recommended to do muxing as part of IOdelay recalibration.
IODELAY recalibration sequence:
- Complete AVS voltage change on VDD_CORE_L
- Unlock IODLAY config registers.
- Perform IO delay calibration with predefined values.
- Isolate all the IOs
- Update the delay mechanism for each IO with new calibrated values.
- Configure PAD configuration registers
- De-isolate all the IOs.
- Relock IODELAY config registers.
Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>
Signed-off-by: Nishanth Menon <nm@ti.com>
