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>
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>
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>
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