feat(dsu): support power control and autonomous powerdown config
This patch allows platforms to enable certain DSU settings
to ensure memory retention and control over
cache power requests. We also move the driver out of css
into drivers/arm. Platforms can configure the
CLUSTERPWRCTLR and CLUSTERPWRDN registers [1] to improve
power efficiency.
These registers enable finer-grained control of
DSU power state transitions, including
powerdown and retention.
IMP_CLUSTERPWRCTLR_EL1 provides:
- Functional retention: Allows configuration of the
duration of inactivity before the DSU uses
CLUSTERPACTIVE to request functional retention.
- Cache power request: These bits are output on
CLUSTERPACTIVE[19:16] to indicate to the power controller
which cache portions must remain powered.
IMP_CLUSTERPWRDN_EL1 includes:
- Powerdown: Triggers full cluster powerdown, including
control logic.
- Memory retention: Requests memory retention mode,
keeping L3 RAM contents while powering off
the rest of the DSU.
The DSU-120 TRM [2] provides the full field definitions,
which are used as references in the `dsu_driver_data` structure.
References:
[1]: https://developer.arm.com/documentation/100453/latest/
[2]: https://developer.arm.com/documentation/102547/0201/?lang=en
Signed-off-by: Arvind Ram Prakash <arvind.ramprakash@arm.com>
Change-Id: I2eba808b8f2a27797782a333c65dd092b03208fe
diff --git a/docs/getting_started/build-options.rst b/docs/getting_started/build-options.rst
index 9d2df33..f99840b 100644
--- a/docs/getting_started/build-options.rst
+++ b/docs/getting_started/build-options.rst
@@ -1119,6 +1119,11 @@
(Coherent memory region is included) or 0 (Coherent memory region is
excluded). Default is 1.
+- ``USE_DSU_DRIVER``: This flag enables DSU (DynamIQ Shared Unit) driver.
+ The DSU driver allows save/restore of DSU PMU registers through
+ ``PRESERVE_DSU_PMU_REGS`` build option and allows platforms to
+ configure powerdown and power settings of DSU.
+
- ``ARM_IO_IN_DTB``: This flag determines whether to use IO based on the
firmware configuration framework. This will move the io_policies into a
configuration device tree, instead of static structure in the code base.