On warm reset, all cores jump to the low_power_start function because iRAM data is retained and because while executing iROM code all cores find the jump flag 0x02020028 set. In low_power_start, cores check the reset status and if true they clear the jump flag and jump back to 0x0.
The A7 cores do jump to 0x0 but consider following instructions as a Thumb instructions which in turn makes them loop inside the iROM code instead of jumping to power_down_core.
This issue is fixed by replacing the "mov pc" instruction with a "bx" instruction which switches state along with the jump to make the execution unit consider the branch target as an ARM instruction.
Signed-off-by: Akshay Saraswat akshay.s@samsung.com Reviewed-by: Simon Glass sjg@chromium.org Tested-by: Simon Glass sjg@chromium.org --- Changes since v2: - No change.
Changes since v1: - Added Reviewed-by & Tested-by.
arch/arm/cpu/armv7/exynos/lowlevel_init.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/arm/cpu/armv7/exynos/lowlevel_init.c b/arch/arm/cpu/armv7/exynos/lowlevel_init.c index fc7e6f5..36a008a 100644 --- a/arch/arm/cpu/armv7/exynos/lowlevel_init.c +++ b/arch/arm/cpu/armv7/exynos/lowlevel_init.c @@ -125,7 +125,7 @@ static void low_power_start(void) reg_val = readl(EXYNOS5420_SPARE_BASE); if (reg_val != CPU_RST_FLAG_VAL) { writel(0x0, CONFIG_LOWPOWER_FLAG); - set_pc(0x0); + branch_bx(0x0); }
reg_val = readl(CONFIG_PHY_IRAM_BASE + 0x4);