This series introduces support for the RPMh (Resource Power Manager (hardened)) co-processor and associated regulator driver found on most modern Qualcomm platforms (since ~2017).
Even though most regulators are controlled via SPMI, the specific regions on the PMICs for controlling the regulators are restricted and can't be accessed by the Applications Processor (AP/HLOS). Instead, these resources are proxied via the RPMh where they can be voted on by multiple subsystems (Linux, the modem, and the other DSPs). This is done for security (to protect clocks, power domains, and regulators that are specifically relevant for the trustzone) as well as to simplify the management of shared peripherals and to allow for handover of peripherals like the USB controller.
For U-Boot, our main concern is the regulators. Since all regulators on the system are controlled via the RPMh, it is necessary to support it to enable USB VBUS on some platforms, and may be needed for other peripherals in the future.
Communicating with the RPMh additional requires accessing the cmd-db shared memory region, this contains key/value maps to determine the address of specific resources on the RPMh.
Introduce support for the cmd-db, the RPMh framework, and some of the regulators that are necessary to enable USB VBUS on the RB5 development board.
These drivers were originally taken from Linux, however they have been heavily modified and simplified for U-Boot. Since the original Linux drivers contained heavy optimisations related to multithreading and asynchronous probing, as well as support for idle and suspend states which we don't need to deal with here.
The U-Boot version of the driver supports a single TCS and always requests a response from the RPMh, since we don't need to worry about having multiple transactions in flight at once.
--- Caleb Connolly (3): linux/bitmap.h: add bitmap_empty helper soc: qcom: rpmh and cmd-db drivers power: regulator: add qcom-rpmh-regulator
drivers/power/regulator/Kconfig | 8 + drivers/power/regulator/Makefile | 1 + drivers/power/regulator/qcom-rpmh-regulator.c | 534 ++++++++++++++++++++++ drivers/soc/Kconfig | 1 + drivers/soc/Makefile | 1 + drivers/soc/qcom/Kconfig | 25 ++ drivers/soc/qcom/Makefile | 4 + drivers/soc/qcom/cmd-db.c | 246 ++++++++++ drivers/soc/qcom/rpmh-internal.h | 141 ++++++ drivers/soc/qcom/rpmh-rsc.c | 619 ++++++++++++++++++++++++++ drivers/soc/qcom/rpmh.c | 110 +++++ include/linux/bitmap.h | 8 + include/soc/qcom/cmd-db.h | 42 ++ include/soc/qcom/rpmh.h | 29 ++ include/soc/qcom/tcs.h | 78 ++++ 15 files changed, 1847 insertions(+) --- change-id: 20240611-b4-qcom-rpmh-fcfd32ac2940 base-commit: 65134a67bca5e11415e93262e530b1c91fee154f
// Caleb (they/them)