diff options
Diffstat (limited to 'plat/allwinner/sun50i_a64/sunxi_power.c')
-rw-r--r-- | plat/allwinner/sun50i_a64/sunxi_power.c | 53 |
1 files changed, 53 insertions, 0 deletions
diff --git a/plat/allwinner/sun50i_a64/sunxi_power.c b/plat/allwinner/sun50i_a64/sunxi_power.c index 80a69c3404..0fdb62d057 100644 --- a/plat/allwinner/sun50i_a64/sunxi_power.c +++ b/plat/allwinner/sun50i_a64/sunxi_power.c @@ -14,6 +14,7 @@ #include <drivers/allwinner/sunxi_rsb.h> #include <lib/mmio.h> +#include <core_off_arisc.h> #include <sunxi_def.h> #include <sunxi_mmap.h> #include <sunxi_private.h> @@ -205,3 +206,55 @@ void sunxi_power_down(void) } } + +/* This lock synchronises access to the arisc management processor. */ +static DEFINE_BAKERY_LOCK(arisc_lock); + +/* + * If we are supposed to turn ourself off, tell the arisc SCP to do that + * work for us. Without any SCPI provider running there, we place some + * OpenRISC code into SRAM, put the address of that into the reset vector + * and release the arisc reset line. The SCP will wait for the core to enter + * WFI, then execute that code and pull the line up again. + * The code expects the core mask to be patched into the first instruction. + */ +void sunxi_cpu_power_off_self(void) +{ + u_register_t mpidr = read_mpidr(); + unsigned int core = MPIDR_AFFLVL0_VAL(mpidr); + uintptr_t arisc_reset_vec = SUNXI_SRAM_A2_BASE + 0x100; + uint32_t *code = arisc_core_off; + + do { + bakery_lock_get(&arisc_lock); + /* Wait until the arisc is in reset state. */ + if (!(mmio_read_32(SUNXI_R_CPUCFG_BASE) & BIT(0))) + break; + + bakery_lock_release(&arisc_lock); + } while (1); + + /* Patch up the code to feed in an input parameter. */ + code[0] = (code[0] & ~0xffff) | BIT_32(core); + clean_dcache_range((uintptr_t)code, sizeof(arisc_core_off)); + + /* + * The OpenRISC unconditional branch has opcode 0, the branch offset + * is in the lower 26 bits, containing the distance to the target, + * in instruction granularity (32 bits). + */ + mmio_write_32(arisc_reset_vec, ((uintptr_t)code - arisc_reset_vec) / 4); + clean_dcache_range(arisc_reset_vec, 4); + + /* De-assert the arisc reset line to let it run. */ + mmio_setbits_32(SUNXI_R_CPUCFG_BASE, BIT(0)); + + /* + * We release the lock here, although the arisc is still busy. + * But as long as it runs, the reset line is high, so other users + * won't leave the loop above. + * Once it has finished, the code is supposed to clear the reset line, + * to signal this to other users. + */ + bakery_lock_release(&arisc_lock); +} |