Hi,
a long-standing issue in the ZynqMP users community is the management on the PMU firmware configuration object when U-Boot SPL is used.
The Platform Management Unit (PMU) needs a configuration object (cfg obj) to know how to operate the SoC. When using the "Xilinx workflow", the Xilinx FSBL (First Stage Bootloader) has the SPL role. FSBL has a built-in cfg obj and passes it to the PMUFW at runtime before jumping to U-Boot proper.
This is just not implemented in the U-Boot code. The best workaround for U-Boot SPL users is to patch [0] the PMUFW itself to have the cfg obj built-in and self-load it. This approach has some drawbacks: among others, it forces to use a different PMUFW binary for each hardware and hardware configuation. It also makes it impossible to change the configuration after boot.
This patchset is a first attempt at filling the gap by allowing U-Boot SPL to load the cfg obj firmware at runtime. It adds a Kconfig string option to point to the cfg obj in the form of a C file as produced by Xilinx tools (usually called pm_cfg_obj.c). If the option is non-empty, code is enabled to compile that file in U-Boot SPL and send the configuration to PMUFW.
The next development target will be to load the cfg obj from a binary blob instead of compiling it from a .c file. With that in place, patch 1 will be removed and patch 2 cleaned up.
These patches are tested on the UltraZed EV board.
Since RFC v1 [1] the loading has been reimplemented in SPL (it was in U-Boot proper). Now it does not rely on ARM Trusted Firmware but instead talks directly with the PMU via IPI mailboxes.
[0] https://github.com/topic-embedded-products/meta-topic/blob/master/recipes-bs... [1] https://lists.denx.de/pipermail/u-boot/2019-February/360450.html
Luca
Luca Ceresoli (2): zynqmp: add minimal include files to build a pm_cfg_obj.c arm64: zynqmp: spl: install a PMU firmware config object at runtime
board/xilinx/zynqmp/Kconfig | 26 ++++ board/xilinx/zynqmp/Makefile | 5 + board/xilinx/zynqmp/pm_defs.h | 254 +++++++++++++++++++++++++++++++ board/xilinx/zynqmp/pmu_global.h | 0 board/xilinx/zynqmp/pmu_ipc.c | 116 ++++++++++++++ board/xilinx/zynqmp/pmu_ipc.h | 14 ++ board/xilinx/zynqmp/xil_types.h | 1 + board/xilinx/zynqmp/zynqmp.c | 11 ++ 8 files changed, 427 insertions(+) create mode 100644 board/xilinx/zynqmp/pm_defs.h create mode 100644 board/xilinx/zynqmp/pmu_global.h create mode 100644 board/xilinx/zynqmp/pmu_ipc.c create mode 100644 board/xilinx/zynqmp/pmu_ipc.h create mode 100644 board/xilinx/zynqmp/xil_types.h