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authorDaniel Kurtz <djkurtz@chromium.org>2019-01-14 14:45:47 -0700
committerMartin Roth <martinroth@google.com>2019-01-16 18:20:36 +0000
commitb82afce18aff24b6e5e3b73a67a6533cc4865a26 (patch)
tree772e5e50b47e354b7e6ab4e3ef8172dbb0100a96 /util/exynos/description.md
parentac1a5a82181c3276963807c4a11ab5edb5eb52f7 (diff)
soc/amd/stoneyridge/gpio: Configure debounce for irq gpios
FT4 has a strange property where whenever the debounce registers for any one gpio are changed, the FT4 disables interrupt propagation for ALL gpio irqs for ~4ms. In other words, if an edge interrupt of one gpio happens exactly during this debounce-irq-off window immediately following the configuration of another gpio, the interrupt will be lost. It is quite difficult to deal with this in the kernel, since during kernel boot time, drivers & devices are probed asynchronously, meaning it may happen that an already loaded driver may miss an interrupt when some later driver is being probed and configuring its gpio interrupt. To eliminate this possibility, we pre-configure the debounce registers in ram stage for all gpios that will be used as irqs later by the kernel using the same configuration as used by the kernel, as per this table: IRQ Debounce Edge Remove Glitch Level High Preserve Low Glitch Level Low Preserve High Glitch Signed-off-by: Daniel Kurtz <djkurtz@chromium.org> BUG=b:113880780 BRANCH=none TEST=Reboot stress test grunt (>100 times); no messages in dmesg like: tpm tpm0: Timeout waiting for TPM ready Change-Id: I94c7ecfb14e5bb209b3598e10287c80eb19da25b Reviewed-on: https://review.coreboot.org/c/30921 Tested-by: build bot (Jenkins) <no-reply@coreboot.org> Reviewed-by: Martin Roth <martinroth@google.com>
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