diff options
Diffstat (limited to 'plat/arm/board/juno/aarch64/juno_helpers.S')
| -rw-r--r-- | plat/arm/board/juno/aarch64/juno_helpers.S | 94 |
1 files changed, 94 insertions, 0 deletions
diff --git a/plat/arm/board/juno/aarch64/juno_helpers.S b/plat/arm/board/juno/aarch64/juno_helpers.S index ac54ac9b..49fef16f 100644 --- a/plat/arm/board/juno/aarch64/juno_helpers.S +++ b/plat/arm/board/juno/aarch64/juno_helpers.S @@ -34,12 +34,18 @@ #include <cortex_a53.h> #include <cortex_a57.h> #include <cortex_a72.h> +#include <cpu_macros.S> +#include <css_def.h> #include <v2m_def.h> #include "../juno_def.h" .globl plat_reset_handler .globl plat_arm_calc_core_pos +#if JUNO_AARCH32_EL3_RUNTIME + .globl plat_get_my_entrypoint + .globl juno_reset_to_aarch32_state +#endif #define JUNO_REVISION(rev) REV_JUNO_R##rev #define JUNO_HANDLER(rev) plat_reset_handler_juno_r##rev @@ -206,6 +212,20 @@ func plat_reset_handler endfunc plat_reset_handler /* ----------------------------------------------------- + * void juno_do_reset_to_aarch32_state(void); + * + * Request warm reset to AArch32 mode. + * ----------------------------------------------------- + */ +func juno_do_reset_to_aarch32_state + mov x0, #RMR_EL3_RR_BIT + dsb sy + msr rmr_el3, x0 + isb + wfi +endfunc juno_do_reset_to_aarch32_state + + /* ----------------------------------------------------- * unsigned int plat_arm_calc_core_pos(u_register_t mpidr) * Helper function to calculate the core position. * ----------------------------------------------------- @@ -213,3 +233,77 @@ endfunc plat_reset_handler func plat_arm_calc_core_pos b css_calc_core_pos_swap_cluster endfunc plat_arm_calc_core_pos + +#if JUNO_AARCH32_EL3_RUNTIME + /* --------------------------------------------------------------------- + * uintptr_t plat_get_my_entrypoint (void); + * + * Main job of this routine is to distinguish between a cold and a warm + * boot. On JUNO platform, this distinction is based on the contents of + * the Trusted Mailbox. It is initialised to zero by the SCP before the + * AP cores are released from reset. Therefore, a zero mailbox means + * it's a cold reset. If it is a warm boot then a request to reset to + * AArch32 state is issued. This is the only way to reset to AArch32 + * in EL3 on Juno. A trampoline located at the high vector address + * has already been prepared by BL1. + * + * This functions returns the contents of the mailbox, i.e.: + * - 0 for a cold boot; + * - request warm reset in AArch32 state for warm boot case; + * --------------------------------------------------------------------- + */ +func plat_get_my_entrypoint + mov_imm x0, PLAT_ARM_TRUSTED_MAILBOX_BASE + ldr x0, [x0] + cbz x0, return + b juno_do_reset_to_aarch32_state +1: + b 1b +return: + ret +endfunc plat_get_my_entrypoint + +/* + * Emit a "movw r0, #imm16" which moves the lower + * 16 bits of `_val` into r0. + */ +.macro emit_movw _reg_d, _val + mov_imm \_reg_d, (0xe3000000 | \ + ((\_val & 0xfff) | \ + ((\_val & 0xf000) << 4))) +.endm + +/* + * Emit a "movt r0, #imm16" which moves the upper + * 16 bits of `_val` into r0. + */ +.macro emit_movt _reg_d, _val + mov_imm \_reg_d, (0xe3400000 | \ + (((\_val & 0x0fff0000) >> 16) | \ + ((\_val & 0xf0000000) >> 12))) +.endm + +/* + * This function writes the trampoline code at HI-VEC (0xFFFF0000) + * address which loads r0 with the entrypoint address for + * BL32 (a.k.a SP_MIN) when EL3 is in AArch32 mode. A warm reset + * to AArch32 mode is then requested by writing into RMR_EL3. + */ +func juno_reset_to_aarch32_state + emit_movw w0, BL32_BASE + emit_movt w1, BL32_BASE + /* opcode "bx r0" to branch using r0 in AArch32 mode */ + mov_imm w2, 0xe12fff10 + + /* Write the above opcodes at HI-VECTOR location */ + mov_imm x3, HI_VECTOR_BASE + str w0, [x3], #4 + str w1, [x3], #4 + str w2, [x3] + + bl juno_do_reset_to_aarch32_state +1: + b 1b +endfunc juno_reset_to_aarch32_state + +#endif /* JUNO_AARCH32_EL3_RUNTIME */ |