Consolidate and improve NVIDIA Tegra CPUIDLE driver(s)

Hello,

This series does the following:

1. Unifies Tegra20/30/114 drivers into a single driver and moves it out into common drivers/cpuidle/ directory.

2. Prepares upcoming CPU cluster power-down idling state enabling for

     Tegra30.

In the end there is a quite nice clean up of the Tegra CPUIDLE drivers and of the Tegra's arch code in general. Please apply, thanks!

!!!WARNING!!! This series was made on top of the cpufreq patches [1]. But it
should be fine as long as Thierry Reding would pick up this and the cpufreq patchsets via the Tegra tree, otherwise there will one minor merge-conflict.

[1] https://patchwork.ozlabs.org/project/linux-tegra/list/?series=158206

Changelog:

v11: - Added acks from Daniel Lezcano.

- Added t-b from Nicolas Chauvet.

- @Daniel Lezcano: In regards to -M, I assume it's useless. The cpuidle-tegra driver was rewritten from scratch, it's not a simple code move.

rename arch/arm/mach-tegra/cpuidle-tegra20.c => drivers/cpuidle/cpuidle-tegra.c (9%)

- Replaced ktime_get() with udelay(), thanks to Daniel Lezcano for the suggestion.

- Note to Thierry: this series uses [1] + next-20200218 for the base, you could also cherry-pick the patches from the grate-kernel if it makes things easier (it is up-to-date).

v10: - Added acks from Peter De Schrijver.

- Added tested-by from Peter Geis, Jasper Korten and David Heidelberg who tested these patches on Ouya, TF300T and Nexus 7 devices.

- Temporarily dropped the "cpuidle: tegra: Support CPU cluster power-down state on Tegra30" patch because Michał Mirosław reported that it didn't work well on his TF300T. After some testing we found that changing a way in which firmware performs L2 cache maintenance helps, but later on we also found that the current v9 series works just fine without the extra firmware changes using recent linux-next and the reason why v8 didn't work before is still unknown (need more testing). So I decided that it will be better to postpone the dropped patch until we know for sure that it works well for everyone in every possible configuration.

- Rebased this series on top of recent linux-next, in a result dropped the "cpuidle: Avoid NULL dereference in cpuidle_driver_state_disabled()" patch because it's not needed anymore.

v9: - Rebased on recent linux-next. Dropped the v8 "Avoid NULL dereference.."
patch as a result, it's not needed anymore.

- Temporarily dropped "cpuidle: tegra: Support CPU cluster power-down state on Tegra30" patch because Michał Mirosław reported that it causes problem for ASUS TF300T Tegra30 device, we'll have to resolve the problem first.

- Added ACKs from Peter De Schrijver to the patches.

v8: - Rebased on recent linux-next, now making use of
cpuidle_driver_state_disabled(). Added new patch to make this new API usable by the updated Tegra cpuidle driver:

cpuidle: Avoid NULL dereference in cpuidle_driver_state_disabled()

- Added new patch to handle case where LP2 isn't available:

cpuidle: tegra: Disable CC6 state if LP2 unavailable

v7: - drivers/cpuidle/cpuidle-tegra.c now includes an explicit comment that
clarifies the new terminology that is used for naming of the idling states. This change was suggested by Peter De Schrijver in the review comment to v6. See the comment to struct tegra_idle_driver in the code.

- (!) This series is now based on top of the "NVIDIA Tegra20 CPUFreq driver major update" patchset. The conflict between these two series is trivial to resolve, but still it's worth to mention about that.

v6: - Addressed request from Thierry Reding to change the way patches are
organized by making changes in a more incremental manner.

- tegra_sleep_cpu() now checks for the secondary CPUs to be offline in the "Make outer_disable() open-coded" patch.

v5: - Rebased on a recent linux-next, fixed one minor conflict in Kconfig.

- Improved commit's message of the "Support CPU cluster power-down state on Tegra30" patch.

- The "Support CPU cluster power-down state on Tegra30" patch is also got split and now there is additional "Make outer_disable() open-coded" patch.

- Made minor cosmetic changes to the "Introduce unified driver for NVIDIA Tegra SoCs" patch by improving error message and renaming one variable.

v4: - Fixed compilation with !CONFIG_CACHE_L2X0 (and tested that it still
works).

- Replaced ktime_compare() with ktime_before() in the new driver, for consistency.

v3: - Addressed review comments that were made by Jon Hunter to v2 by
splitting patches into smaller (and simpler) chunks, better documenting changes in the commit messages and using proper error codes in the code.

Warnings are replaced with a useful error messages in the code of "Introduce unified driver for NVIDIA Tegra SoCs" patch.

Secondary CPUs parking timeout increased to 100ms because I found that it actually may happen to take more than 1ms if CPU is running on a *very* low frequency.

Added diagnostic messages that are reporting Flow Controller state when CPU parking fails.

Further polished cpuidle driver's code.

The coupled state entering is now aborted if there is a pending SGI (Software Generated Interrupt) because it will be lost after GIC's power-cycling. Like it was done by the old Tegra20 CPUIDLE driver.

v2: - Added patches to enable the new cpuidle driver in the defconfigs:

ARM: multi_v7_defconfig: Enable Tegra cpuidle driver
ARM: tegra: Enable Tegra cpuidle driver in tegra_defconfig

- Dropped patches that removed CPUIDLE_FLAG_TIMER_STOP from the idling states because that flag actually doesn't have any negative effects, but still is correct for the case of a local CPU timer on older Tegra SoCs:

cpuidle: tegra: Remove CPUIDLE_FLAG_TIMER_STOP from Tegra114/124 idle-state
cpuidle: tegra: Remove CPUIDLE_FLAG_TIMER_STOP from all states

- The "Add unified driver for NVIDIA Tegra SoCs" patch got more polish. Tegra30 and Terga114 states are now squashed into a single common C7 state (following Parker TRM terminology, see 17.2.2.2 Power Management States), more comments added, etc minor changes.

Dmitry Osipenko (17):
ARM: tegra: Compile sleep-tegra20/30.S unconditionally
ARM: tegra: Add tegra_pm_park_secondary_cpu()
ARM: tegra: Remove pen-locking from cpuidle-tegra20
ARM: tegra: Change tegra_set_cpu_in_lp2() type to void
ARM: tegra: Propagate error from tegra_idle_lp2_last()
ARM: tegra: Expose PM functions required for new cpuidle driver
ARM: tegra: Rename some of the newly exposed PM functions
ARM: tegra: Make outer_disable() open-coded
arm: tegra20: cpuidle: Handle case where secondary CPU hangs on
entering LP2
arm: tegra20: cpuidle: Make abort_flag atomic
arm: tegra20/30: cpuidle: Remove unnecessary memory barrier
cpuidle: Refactor and move out NVIDIA Tegra20 driver into
drivers/cpuidle
cpuidle: tegra: Squash Tegra30 driver into the common driver
cpuidle: tegra: Squash Tegra114 driver into the common driver
cpuidle: tegra: Disable CC6 state if LP2 unavailable
ARM: multi_v7_defconfig: Enable Tegra cpuidle driver
ARM: tegra: Enable Tegra cpuidle driver in tegra_defconfig

 arch/arm/configs/multi_v7_defconfig           |   1 +
 arch/arm/configs/tegra_defconfig              |   1 +
 arch/arm/mach-tegra/Makefile                  |  19 +-
 arch/arm/mach-tegra/cpuidle-tegra114.c        |  89 ----
 arch/arm/mach-tegra/cpuidle-tegra20.c         | 212 ----------
 arch/arm/mach-tegra/cpuidle-tegra30.c         | 132 ------
 arch/arm/mach-tegra/cpuidle.c                 |  50 ---
 arch/arm/mach-tegra/cpuidle.h                 |  21 -
 arch/arm/mach-tegra/irq.c                     |   3 +-
 arch/arm/mach-tegra/pm.c                      |  54 ++-
 arch/arm/mach-tegra/pm.h                      |   4 -
 arch/arm/mach-tegra/reset-handler.S           |  11 -
 arch/arm/mach-tegra/reset.h                   |   9 +-
 arch/arm/mach-tegra/sleep-tegra20.S           | 170 --------
 arch/arm/mach-tegra/sleep-tegra30.S           |   6 +-
 arch/arm/mach-tegra/sleep.h                   |  15 -
 arch/arm/mach-tegra/tegra.c                   |   7 +-
 drivers/cpuidle/Kconfig.arm                   |   8 +
 drivers/cpuidle/Makefile                      |   1 +
 drivers/cpuidle/cpuidle-tegra.c               | 392 ++++++++++++++++++
 include/soc/tegra/cpuidle.h                   |   2 +-
 .../mach-tegra => include/soc/tegra}/irq.h    |   8 +-
 include/soc/tegra/pm.h                        |  31 ++
 23 files changed, 485 insertions(+), 761 deletions(-)
 delete mode 100644 arch/arm/mach-tegra/cpuidle-tegra114.c
 delete mode 100644 arch/arm/mach-tegra/cpuidle-tegra20.c
 delete mode 100644 arch/arm/mach-tegra/cpuidle-tegra30.c
 delete mode 100644 arch/arm/mach-tegra/cpuidle.c
 delete mode 100644 arch/arm/mach-tegra/cpuidle.h
 create mode 100644 drivers/cpuidle/cpuidle-tegra.c
 rename {arch/arm/mach-tegra => include/soc/tegra}/irq.h (59%)

2.24.0