Add a callback interface, riscv_hart_early_init() to perform riscv CPU hart-dependent configuration for each hart. riscv_hart_early_init() is placed after stack of harts are initialized and before main boot hart is picked up. Several conditions should be aware of or avoided are listed:
- cannot access gd At the moment, gd hasn't initialized yet.
- all operations in riscv_hart_early_init() should only affect core itself For example, the operations for board level should be moved to mach_xxx() or board_init_xxx() functions instead.
- Common resource need protection if multicore Since all harts might enter riscv_hart_early_init() in parallel, common resource need a mechanism to handle race condition.
- A dummy implementation is added in ./arch/riscv/cpu/cpu.c The implementation is declared with '__weak' and can be overridden.
Changelogs: v4 - Revising the comments for riscv_hart_early_init() in [1/2] - Remove unnecessary braces and add reviewed-by in [2/2]
Green Wan (2): arch: riscv: cpu: Add callback to init each core board: sifive: unmatched: clear feature disable CSR
arch/riscv/cpu/cpu.c | 15 +++++++++++++++ arch/riscv/cpu/start.S | 14 ++++++++++++++ board/sifive/unmatched/spl.c | 15 +++++++++++++++ 3 files changed, 44 insertions(+)