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authorIvy Jian <ivy.jian@quanta.corp-partner.google.com>2022-09-05 11:30:48 +0800
committerSubrata Banik <subratabanik@google.com>2022-09-08 16:00:04 +0000
commit66757b121ab39b168f1059932797f80bc512c35a (patch)
treecf10aedfa7cbdad98431beea398cbcae9b44b50e /src/mainboard/google/hatch/variants
parentd29b4aef1c110a04c1a03b44d5040b5702d02738 (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>
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