diff options
Diffstat (limited to 'arch/riscv/cpu/start.S')
| -rw-r--r-- | arch/riscv/cpu/start.S | 167 |
1 files changed, 157 insertions, 10 deletions
diff --git a/arch/riscv/cpu/start.S b/arch/riscv/cpu/start.S index 81ea52b170..a4433fbd6b 100644 --- a/arch/riscv/cpu/start.S +++ b/arch/riscv/cpu/start.S @@ -13,6 +13,7 @@ #include <config.h> #include <common.h> #include <elf.h> +#include <asm/csr.h> #include <asm/encoding.h> #include <generated/asm-offsets.h> @@ -32,11 +33,19 @@ #define SYM_SIZE 0x18 #endif +.section .data +secondary_harts_relocation_error: + .ascii "Relocation of secondary harts has failed, error %d\n" + .section .text .globl _start _start: +#ifdef CONFIG_RISCV_MMODE + csrr a0, mhartid +#endif + /* save hart id and dtb pointer */ - mv s0, a0 + mv tp, a0 mv s1, a1 la t0, trap_entry @@ -45,9 +54,22 @@ _start: /* mask all interrupts */ csrw MODE_PREFIX(ie), zero - /* Enable cache */ - jal icache_enable - jal dcache_enable +#ifdef CONFIG_SMP + /* check if hart is within range */ + /* tp: hart id */ + li t0, CONFIG_NR_CPUS + bge tp, t0, hart_out_of_bounds_loop +#endif + +#ifdef CONFIG_SMP + /* set xSIE bit to receive IPIs */ +#ifdef CONFIG_RISCV_MMODE + li t0, MIE_MSIE +#else + li t0, SIE_SSIE +#endif + csrs MODE_PREFIX(ie), t0 +#endif /* * Set stackpointer in internal/ex RAM to call board_init_f @@ -57,14 +79,33 @@ call_board_init_f: li t1, CONFIG_SYS_INIT_SP_ADDR and sp, t1, t0 /* force 16 byte alignment */ -#ifdef CONFIG_DEBUG_UART - jal debug_uart_init -#endif - call_board_init_f_0: mv a0, sp jal board_init_f_alloc_reserve + + /* + * Set global data pointer here for all harts, uninitialized at this + * point. + */ + mv gp, a0 + + /* setup stack */ +#ifdef CONFIG_SMP + /* tp: hart id */ + slli t0, tp, CONFIG_STACK_SIZE_SHIFT + sub sp, a0, t0 +#else mv sp, a0 +#endif + + /* + * Pick hart to initialize global data and run U-Boot. The other harts + * wait for initialization to complete. + */ + la t0, hart_lottery + li s2, 1 + amoswap.w s2, t1, 0(t0) + bnez s2, wait_for_gd_init la t0, prior_stage_fdt_address SREG s1, 0(t0) @@ -72,7 +113,42 @@ call_board_init_f_0: jal board_init_f_init_reserve /* save the boot hart id to global_data */ - SREG s0, GD_BOOT_HART(gp) + SREG tp, GD_BOOT_HART(gp) + + la t0, available_harts_lock + fence rw, w + amoswap.w zero, zero, 0(t0) + +wait_for_gd_init: + la t0, available_harts_lock + li t1, 1 +1: amoswap.w t1, t1, 0(t0) + fence r, rw + bnez t1, 1b + + /* register available harts in the available_harts mask */ + li t1, 1 + sll t1, t1, tp + LREG t2, GD_AVAILABLE_HARTS(gp) + or t2, t2, t1 + SREG t2, GD_AVAILABLE_HARTS(gp) + + fence rw, w + amoswap.w zero, zero, 0(t0) + + /* + * Continue on hart lottery winner, others branch to + * secondary_hart_loop. + */ + bnez s2, secondary_hart_loop + + /* Enable cache */ + jal icache_enable + jal dcache_enable + +#ifdef CONFIG_DEBUG_UART + jal debug_uart_init +#endif mv a0, zero /* a0 <-- boot_flags = 0 */ la t5, board_init_f @@ -95,7 +171,14 @@ relocate_code: *Set up the stack */ stack_setup: +#ifdef CONFIG_SMP + /* tp: hart id */ + slli t0, tp, CONFIG_STACK_SIZE_SHIFT + sub sp, s2, t0 +#else mv sp, s2 +#endif + la t0, _start sub t6, s4, t0 /* t6 <- relocation offset */ beq t0, s4, clear_bss /* skip relocation */ @@ -175,13 +258,37 @@ clear_bss: add t0, t0, t6 /* t0 <- rel __bss_start in RAM */ la t1, __bss_end /* t1 <- rel __bss_end in FLASH */ add t1, t1, t6 /* t1 <- rel __bss_end in RAM */ - beq t0, t1, call_board_init_r + beq t0, t1, relocate_secondary_harts clbss_l: SREG zero, 0(t0) /* clear loop... */ addi t0, t0, REGBYTES bne t0, t1, clbss_l +relocate_secondary_harts: +#ifdef CONFIG_SMP + /* send relocation IPI */ + la t0, secondary_hart_relocate + add a0, t0, t6 + + /* store relocation offset */ + mv s5, t6 + + mv a1, s2 + mv a2, s3 + jal smp_call_function + + /* hang if relocation of secondary harts has failed */ + beqz a0, 1f + mv a1, a0 + la a0, secondary_harts_relocation_error + jal printf + jal hang + + /* restore relocation offset */ +1: mv t6, s5 +#endif + /* * We are done. Do not return, instead branch to second part of board * initialization, now running from RAM. @@ -202,3 +309,43 @@ call_board_init_r: * jump to it ... */ jr t4 /* jump to board_init_r() */ + +#ifdef CONFIG_SMP +hart_out_of_bounds_loop: + /* Harts in this loop are out of bounds, increase CONFIG_NR_CPUS. */ + wfi + j hart_out_of_bounds_loop +#endif + +#ifdef CONFIG_SMP +/* SMP relocation entry */ +secondary_hart_relocate: + /* a1: new sp */ + /* a2: new gd */ + /* tp: hart id */ + + /* setup stack */ + slli t0, tp, CONFIG_STACK_SIZE_SHIFT + sub sp, a1, t0 + + /* update global data pointer */ + mv gp, a2 +#endif + +secondary_hart_loop: + wfi + +#ifdef CONFIG_SMP + csrr t0, MODE_PREFIX(ip) +#ifdef CONFIG_RISCV_MMODE + andi t0, t0, MIE_MSIE +#else + andi t0, t0, SIE_SSIE +#endif + beqz t0, secondary_hart_loop + + mv a0, tp + jal handle_ipi +#endif + + j secondary_hart_loop |