diff options
Diffstat (limited to 'arch/x86/lib/fsp/fsp_car.S')
| -rw-r--r-- | arch/x86/lib/fsp/fsp_car.S | 124 |
1 files changed, 124 insertions, 0 deletions
diff --git a/arch/x86/lib/fsp/fsp_car.S b/arch/x86/lib/fsp/fsp_car.S new file mode 100644 index 0000000000..5e09568b85 --- /dev/null +++ b/arch/x86/lib/fsp/fsp_car.S @@ -0,0 +1,124 @@ +/* + * Copyright (C) 2014, Bin Meng <bmeng.cn@gmail.com> + * + * SPDX-License-Identifier: GPL-2.0+ + */ + +#include <config.h> +#include <asm/post.h> + +.globl car_init +car_init: + /* + * Note: ebp holds the BIST value (built-in self test) so far, but ebp + * will be destroyed through the FSP call, thus we have to test the + * BIST value here before we call into FSP. + */ + test %ebp, %ebp + jz car_init_start + post_code(POST_BIST_FAILURE) + jmp die + +car_init_start: + post_code(POST_CAR_START) + lea find_fsp_header_romstack, %esp + jmp find_fsp_header + +find_fsp_header_ret: + /* EAX points to FSP_INFO_HEADER */ + mov %eax, %ebp + + /* sanity test */ + cmp $CONFIG_FSP_ADDR, %eax + jb die + + /* calculate TempRamInitEntry address */ + mov 0x30(%ebp), %eax + add 0x1c(%ebp), %eax + + /* call FSP TempRamInitEntry to setup temporary stack */ + lea temp_ram_init_romstack, %esp + jmp *%eax + +temp_ram_init_ret: + addl $4, %esp + cmp $0, %eax + jnz car_init_fail + + post_code(POST_CAR_CPU_CACHE) + + /* + * The FSP TempRamInit initializes the ecx and edx registers to + * point to a temporary but writable memory range (Cache-As-RAM). + * ecx: the start of this temporary memory range, + * edx: the end of this range. + */ + + /* stack grows down from top of CAR */ + movl %edx, %esp + + /* + * TODO: + * + * According to FSP architecture spec, the fsp_init() will not return + * to its caller, instead it requires the bootloader to provide a + * so-called continuation function to pass into the FSP as a parameter + * of fsp_init, and fsp_init() will call that continuation function + * directly. + * + * The call to fsp_init() may need to be moved out of the car_init() + * to cpu_init_f() with the help of some inline assembly codes. + * Note there is another issue that fsp_init() will setup another stack + * using the fsp_init parameter stack_top after DRAM is initialized, + * which means any data on the previous stack (on the CAR) gets lost + * (ie: U-Boot global_data). FSP is supposed to support such scenario, + * however it does not work. This should be revisited in the future. + */ + movl $CONFIG_FSP_TEMP_RAM_ADDR, %eax + xorl %edx, %edx + xorl %ecx, %ecx + call fsp_init + +.global fsp_init_done +fsp_init_done: + /* + * We come here from FspInit with eax pointing to the HOB list. + * Save eax to esi temporarily. + */ + movl %eax, %esi + /* + * Re-initialize the ebp (BIST) to zero, as we already reach here + * which means we passed BIST testing before. + */ + xorl %ebp, %ebp + jmp car_init_ret + +car_init_fail: + post_code(POST_CAR_FAILURE) + +die: + hlt + jmp die + hlt + + /* + * The function call before CAR initialization is tricky. It cannot + * be called using the 'call' instruction but only the 'jmp' with + * the help of a handcrafted stack in the ROM. The stack needs to + * contain the function return address as well as the parameters. + */ + .balign 4 +find_fsp_header_romstack: + .long find_fsp_header_ret + + .balign 4 +temp_ram_init_romstack: + .long temp_ram_init_ret + .long temp_ram_init_params +temp_ram_init_params: +_dt_ucode_base_size: + /* These next two fields are filled in by ifdtool */ + .long 0 /* microcode base */ + .long 0 /* microcode size */ + .long CONFIG_SYS_MONITOR_BASE /* code region base */ + .long CONFIG_SYS_MONITOR_LEN /* code region size */ |