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author | Ivy Jian <ivy.jian@quanta.corp-partner.google.com> | 2022-09-05 11:30:48 +0800 |
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committer | Subrata Banik <subratabanik@google.com> | 2022-09-08 16:00:04 +0000 |
commit | 66757b121ab39b168f1059932797f80bc512c35a (patch) | |
tree | cf10aedfa7cbdad98431beea398cbcae9b44b50e /src/mainboard/google/hatch/variants | |
parent | d29b4aef1c110a04c1a03b44d5040b5702d02738 (diff) |
mb/google/rex: Add WWAN poweron sequencing
The PCIe WWAN module used on rex requires control over 4 signals to
successfully power it on. It is desirable to do this before passing
control to the payload, because the modem requires a ~10 seconds
initialization phase before it can be used.
The corrected sequence looks like:
1) Drive device into full reset and enable power in bootblock
2) Deassert FCPO in romstage, after power rails stabilize
3) Deassert WWAN_RST#, then WWAN_PERST# in ramstage
BUG=b:244077118
TEST=FM350 could be enumerated via lspci
Measured signals to check start-up Timing Sequence, tpr/ton1/ton2.
Tpr = 572mS
Ton1 = 6.3s
Ton2 = 6.3+4.17ms
Signed-off-by: Ivy Jian <ivy.jian@quanta.corp-partner.google.com>
Change-Id: I6cda9348ef7f54efe5ba2358040596a1c2da1b13
Reviewed-on: https://review.coreboot.org/c/coreboot/+/67332
Reviewed-by: Eric Lai <eric_lai@quanta.corp-partner.google.com>
Reviewed-by: Subrata Banik <subratabanik@google.com>
Reviewed-by: Tarun Tuli <taruntuli@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Diffstat (limited to 'src/mainboard/google/hatch/variants')
0 files changed, 0 insertions, 0 deletions