Use SPDX license identifiers ...

To make software license auditing simpler, use SPDX[0] license
identifiers instead of duplicating the license text in every file.

NOTE: Files that have been imported by FreeBSD have not been modified.

[0]: https://spdx.org/

Change-Id: I80a00e1f641b8cc075ca5a95b10607ed9ed8761a
Signed-off-by: dp-arm <dimitris.papastamos@arm.com>

PSCI: Build option to enable D-Caches early in warmboot ...

This patch introduces a build option to enable D-cache early on the CPU
after warm boot. This is applicable for platforms which do not require
interconnect programming to enable cache coherency (eg: single cluster
platforms). If this option is enabled, then warm boot path enables
D-caches immediately after enabling MMU.

Fixes ARM-Software/tf-issues#456

Change-Id: I44c8787d116d7217837ced3bcf0b1d3441c8d80e
Signed-off-by: Soby Mathew <soby.mathew@arm.com>

PSCI: Optimize call paths if all participants are cache-coherent ...

The current PSCI implementation can apply certain optimizations upon the
assumption that all PSCI participants are cache-coherent.

  - Skip performing cache maintenance during power-up.

  - Skip performing cache maintenance during power-down:

    At present, on the power-down path, CPU driver disables caches and
    MMU, and performs cache maintenance in preparation for powering down
    the CPU. This means that PSCI must perform additional cache
    maintenance on the extant stack for correct functioning.

    If all participating CPUs are cache-coherent, CPU driver would
    neither disable MMU nor perform cache maintenance. The CPU being
    powered down, therefore, remain cache-coherent throughout all PSCI
    call paths. This in turn means that PSCI cache maintenance
    operations are not required during power down.

  - Choose spin locks instead of bakery locks:

    The current PSCI implementation must synchronize both cache-coherent
    and non-cache-coherent participants. Mutual exclusion primitives are
    not guaranteed to function on non-coherent memory. For this reason,
    the current PSCI implementation had to resort to bakery locks.

    If all participants are cache-coherent, the implementation can
    enable MMU and data caches early, and substitute bakery locks for
    spin locks. Spin locks make use of architectural mutual exclusion
    primitives, and are lighter and faster.

The optimizations are applied when HW_ASSISTED_COHERENCY build option is
enabled, as it's expected that all PSCI participants are cache-coherent
in those systems.

Change-Id: Iac51c3ed318ea7e2120f6b6a46fd2db2eae46ede
Signed-off-by: Jeenu Viswambharan <jeenu.viswambharan@arm.com>

PSCI: Introduce cache and barrier wrappers ...

The PSCI implementation performs cache maintenance operations on its
data structures to ensure their visibility to both cache-coherent and
non-cache-coherent participants. These cache maintenance operations
can be skipped if all PSCI participants are cache-coherent. When
HW_ASSISTED_COHERENCY build option is enabled, we assume PSCI
participants are cache-coherent.

For usage abstraction, this patch introduces wrappers for PSCI cache
maintenance and barrier operations used for state coordination: they are
effectively NOPs when HW_ASSISTED_COHERENCY is enabled, but are
applied otherwise.

Also refactor local state usage and associated cache operations to make
it clearer.

Change-Id: I77f17a90cba41085b7188c1345fe5731c99fad87
Signed-off-by: Jeenu Viswambharan <jeenu.viswambharan@arm.com>

PSCI: Do stat accounting for retention/standby states ...

Perform stat accounting for retention/standby states also when
requested at multiple power levels.

Change-Id: I2c495ea7cdff8619bde323fb641cd84408eb5762
Signed-off-by: dp-arm <dimitris.papastamos@arm.com>

PSCI: Decouple PSCI stat residency calculation from PMF ...

This patch introduces the following three platform interfaces:

* void plat_psci_stat_accounting_start(const psci_power_state_t *state_info)

  This is an optional hook that platforms can implement in order
  to perform accounting before entering a low power state.  This
  typically involves capturing a timestamp.

* void plat_psci_stat_accounting_stop(const psci_power_state_t *state_info)

  This is an optional hook that platforms can implement in order
  to perform accounting after exiting from a low power state.  This
  typically involves capturing a timestamp.

* u_register_t plat_psci_stat_get_residency(unsigned int lvl,
	const psci_power_state_t *state_info,
	unsigned int last_cpu_index)

  This is an optional hook that platforms can implement in order
  to calculate the PSCI stat residency.

If any of these interfaces are overridden by the platform, it is
recommended that all of them are.

By default `ENABLE_PSCI_STAT` is disabled.  If `ENABLE_PSCI_STAT`
is set but `ENABLE_PMF` is not set then an alternative PSCI stat
collection backend must be provided.  If both are set, then default
weak definitions of these functions are provided, using PMF to
calculate the residency.

NOTE: Previously, platforms did not have to explicitly set
`ENABLE_PMF` since this was automatically done by the top-level
Makefile.

Change-Id: I17b47804dea68c77bc284df15ee1ccd66bc4b79b
Signed-off-by: dp-arm <dimitris.papastamos@arm.com>

Add two timestamps to measure PSCI cache flush overhead ...

Testing showed that the time spent in a cluster power down
operation is dominated by cache flushes.  Add two more timestamps
in runtime instrumentation to keep track of the time spent
flushing the L1/L2 caches.

Change-Id: I4c5a04e7663543225a85d3c6b271d7b706deffc4
Signed-off-by: dp-arm <dimitris.papastamos@arm.com>

Add PMF instrumentation points in TF ...

In order to quantify the overall time spent in the PSCI software
implementation, an initial collection of PMF instrumentation points
has been added.

Instrumentation has been added to the following code paths:

- Entry to PSCI SMC handler.  The timestamp is captured as early
  as possible during the runtime exception and stored in memory
  before entering the PSCI SMC handler.

- Exit from PSCI SMC handler.  The timestamp is captured after
  normal return from the PSCI SMC handler or if a low power state
  was requested it is captured in the bl31 warm boot path before
  return to normal world.

- Entry to low power state.  The timestamp is captured before entry
  to a low power state which implies either standby or power down.
  As these power states are mutually exclusive, only one timestamp
  is defined to describe both.  It is possible to differentiate between
  the two power states using the PSCI STAT interface.

- Exit from low power state.  The timestamp is captured after a standby
  or power up operation has completed.

To calculate the number of cycles spent running code in Trusted Firmware
one can perform the following calculation:

(exit_psci - enter_psci) - (exit_low_pwr - enter_low_pwr).

The resulting number of cycles can be converted to time given the
frequency of the counter.

Change-Id: Ie3b8f3d16409b6703747093b3a2d5c7429ad0166
Signed-off-by: dp-arm <dimitris.papastamos@arm.com>

Fix use of stale power states in PSCI standby finisher ...

A PSCI CPU_SUSPEND request to place a CPU in retention states at power levels
higher than the CPU power level is subject to the same state coordination as a
power down state. A CPU could implement multiple retention states at a
particular power level. When exiting WFI, the non-CPU power levels may be in a
different retention state to what was initially requested, therefore each CPU
should refresh its view of the states of all power levels.

Previously, a CPU re-used the state of the power levels when it entered the
retention state. This patch fixes this issue by ensuring that a CPU upon exit
from retention reads the state of each power level afresh.

Change-Id: I93b5f5065c63400c6fd2598dbaafac385748f989

Introduce PSCI Library Interface ...

This patch introduces the PSCI Library interface. The major changes
introduced are as follows:

* Earlier BL31 was responsible for Architectural initialization during cold
boot via bl31_arch_setup() whereas PSCI was responsible for the same during
warm boot. This functionality is now consolidated by the PSCI library
and it does Architectural initialization via psci_arch_setup() during both
cold and warm boots.

* Earlier the warm boot entry point was always `psci_entrypoint()`. This was
not flexible enough as a library interface. Now PSCI expects the runtime
firmware to provide the entry point via `psci_setup()`. A new function
`bl31_warm_entrypoint` is introduced in BL31 and the previous
`psci_entrypoint()` is deprecated.

* The `smc_helpers.h` is reorganized to separate the SMC Calling Convention
defines from the Trusted Firmware SMC helpers. The former is now in a new
header file `smcc.h` and the SMC helpers are moved to Architecture specific
header.

* The CPU context is used by PSCI for context initialization and
restoration after power down (PSCI Context). It is also used by BL31 for SMC
handling and context management during Normal-Secure world switch (SMC
Context). The `psci_smc_handler()` interface is redefined to not use SMC
helper macros thus enabling to decouple the PSCI context from EL3 runtime
firmware SMC context. This enables PSCI to be integrated with other runtime
firmware using a different SMC context.

NOTE: With this patch the architectural setup done in `bl31_arch_setup()`
is done as part of `psci_setup()` and hence `bl31_platform_setup()` will be
invoked prior to architectural setup. It is highly unlikely that the platform
setup will depend on architectural setup and cause any failure. Please be
be aware of this change in sequence.

Change-Id: I7f497a08d33be234bbb822c28146250cb20dab73

Introduce `el3_runtime` and `PSCI` libraries ...

This patch moves the PSCI services and BL31 frameworks like context
management and per-cpu data into new library components `PSCI` and
`el3_runtime` respectively. This enables PSCI to be built independently from
BL31. A new `psci_lib.mk` makefile is introduced which adds the relevant
PSCI library sources and gets included by `bl31.mk`. Other changes which
are done as part of this patch are:

* The runtime services framework is now moved to the `common/` folder to
  enable reuse.
* The `asm_macros.S` and `assert_macros.S` helpers are moved to architecture
  specific folder.
* The `plat_psci_common.c` is moved from the `plat/common/aarch64/` folder
  to `plat/common` folder. The original file location now has a stub which
  just includes the file from new location to maintain platform compatibility.

Most of the changes wouldn't affect platform builds as they just involve
changes to the generic bl1.mk and bl31.mk makefiles.

NOTE: THE `plat_psci_common.c` FILE HAS MOVED LOCATION AND THE STUB FILE AT
THE ORIGINAL LOCATION IS NOW DEPRECATED. PLATFORMS SHOULD MODIFY THEIR
MAKEFILES TO INCLUDE THE FILE FROM THE NEW LOCATION.

Change-Id: I6bd87d5b59424995c6a65ef8076d4fda91ad5e86