Hi!
The Tegra20 requires an enabled VDE power domain during startup. As the
VDE is currently not used, it is disabled during runtime.
Since 8f0c714ad9be, there is a workaround for the "normal restart path"
which enables the VDE before doing PMC's warm reboot. This workaround is
not executed in the "emergency restart path", leading to a hang-up
during start.
This series implements and registers a new pmic-based restart handler
for boards with tps6586x. This cold reboot ensures that the VDE power
domain is enabled during startup on tegra20-based boards.
Since bae1d3a05a8b, i2c transfers are non-atomic while preemption is
disabled (which is e.g. done during panic()). This could lead to
warnings ("Voluntary context switch within RCU") in i2c-based restart
handlers during emergency restart. The state of preemption should be
detected by i2c_in_atomic_xfer_mode() to use atomic i2c xfer when
required. Beside the new system_state check, the check is the same as
the one pre v5.2.
v5: https://lore.kernel.org/r/20230327-tegra-pmic-reboot-v5-0-ab090e03284d@xxxxxxxxxxx
v6:
- drop 4/6 to abort restart on unexpected failure (suggested by Dmitry)
- 4,5: fix comments in handlers (suggested by Lee)
- 4,5: same delay for both handlers (suggested by Lee)
v5:
- introduce new 3 & 4, therefore 3 -> 5, 4 -> 6
- 3: provide dev to sys_off handler, if it is known
- 4: return NOTIFY_DONE from sys_off_notify, to avoid skipping
- 5: drop Reviewed-by from Dmitry, add poweroff timeout
- 5,6: return notifier value instead of direct errno from handler
- 5,6: use new dev field instead of passing dev as cb_data
- 5,6: increase timeout values based on error observations
- 6: skip unsupported reboot modes in restart handler
---
Benjamin Bara (5):
kernel/reboot: emergency_restart: set correct system_state
i2c: core: run atomic i2c xfer when !preemptible
kernel/reboot: add device to sys_off_handler
mfd: tps6586x: use devm-based power off handler
mfd: tps6586x: register restart handler
drivers/i2c/i2c-core.h | 2 +-
drivers/mfd/tps6586x.c | 55 ++++++++++++++++++++++++++++++++++++++++++--------
include/linux/reboot.h | 3 +++
kernel/reboot.c | 4 ++++
4 files changed, 55 insertions(+), 9 deletions(-)
---
base-commit: 197b6b60ae7bc51dd0814953c562833143b292aa
change-id: 20230327-tegra-pmic-reboot-4175ff814a4b
Best regards,
--
Benjamin Bara <benjamin.bara@xxxxxxxxxxx>
