Reduce maximum timeout from 100ms to 20ms for OTG Enablement polling
for USB Type-C.
Avoid OTG enablement polling when in sink mode
BUG=b:455551151
TEST: Verify USB3.0 (SS) works for C0/C1 on Google/Bluey.
Background:
During USB Type-C port initialization, the OTG (On-The-Go) status must
be verified when the port operates in source mode to ensure proper VBUS
power delivery. The previous implementation polled the OTG status
register with a 100ms timeout on all ports regardless of their role.
Previous Implementation Issues:
1. Overly conservative timeout: The 100ms maximum wait significantly
exceeded actual requirements, as OTG enablement consistently
completes in approximately 14ms under normal conditions
2. Inefficient polling logic: OTG status was polled even when ports
operated in sink mode, where OTG functionality is irrelevant since
the port receives rather than provides power
Improvements:
1. Timeout reduction: Decreased maximum polling duration from 100ms to
20ms, maintaining adequate margin (>40% headroom) while reducing boot
time by up to 80ms per sink-mode port
2. Mode-aware polling: Added logic to detect port role and skip OTG
status polling entirely for sink-mode ports, as demonstrated by the
"Primary in SNK mode - skipping OTG status read" log entry
The changes maintain full USB3.0 SuperSpeed functionality while
improving initialization efficiency. The 20ms timeout remains
sufficiently conservative to accommodate normal timing variations.
Debug logs:
[DEBUG] QMP PHY SS0 initialized and locked in 1671us,
phy_status: 0x86868686
[INFO ] Enabling Primary VBUS SuperSpeed
[INFO ] Primary in SNK mode - skipping OTG status read
[INFO ] Primary Type-C Status:
[INFO ] Misc Status (0x2B0B): 0x1a
[INFO ] Src Status (0x2B08): 0x00
[INFO ] Mode Config (0x2B44): 0x00
[INFO ] Interrupt En Cfg 1 (0x2B5E): 0xff
[INFO ] State Machine Status (0x2B09): 0x02
[DEBUG] USB HS PHY initialized for index 3
[DEBUG] QMP-1x16 USB4 DP PHY SS1 init
[DEBUG] QMP PHY SS1 initialized and locked in 1671us,
phy_status: 0x86868686
[INFO ] Enabling Secondary VBUS SuperSpeed
[INFO ] Secondary in SRC mode - OTG Status: 0x02, State: 0x02
(OTG Enabled) - Time: 14 ms
[INFO ] Secondary Type-C Status:
[INFO ] Misc Status (0x2B0B): 0x4b
[INFO ] Src Status (0x2B08): 0x08
[INFO ] Mode Config (0x2B44): 0x00
[INFO ] Interrupt En Cfg 1 (0x2B5E): 0xff
[INFO ] State Machine Status (0x2B09): 0xa6
confirmed that there are no otg polling for sink mode and
polling timeout is reduced to max of 20ms.
Change-Id: I7467248185c9d0526816ac62e1e1a1496440fddc
Signed-off-by: Hari L <haril@qualcomm.corp-partner.google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/89826
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Kapil Porwal <kapilporwal@google.com>
Reviewed-by: Paul Menzel <paulepanter@mailbox.org>
8449a15aed