For boards that call s_init() when the SPL runs, we are expected to setup an early stack before calling this C function. Implement the proper AArch64 version of this based on the ARMv7 code. This allows sunxi boards to setup the basic peripherals even on with a 64-bit SPL.
Signed-off-by: Andre Przywara andre.przywara@arm.com --- arch/arm/cpu/armv8/Makefile | 1 + arch/arm/cpu/armv8/lowlevel_init.S | 44 ++++++++++++++++++++++++++++++++++++++ 2 files changed, 45 insertions(+) create mode 100644 arch/arm/cpu/armv8/lowlevel_init.S
diff --git a/arch/arm/cpu/armv8/Makefile b/arch/arm/cpu/armv8/Makefile index dea1465..799a752 100644 --- a/arch/arm/cpu/armv8/Makefile +++ b/arch/arm/cpu/armv8/Makefile @@ -25,3 +25,4 @@ obj-$(CONFIG_FSL_LAYERSCAPE) += fsl-layerscape/ obj-$(CONFIG_S32V234) += s32v234/ obj-$(CONFIG_ARCH_ZYNQMP) += zynqmp/ obj-$(CONFIG_TARGET_HIKEY) += hisilicon/ +obj-$(CONFIG_ARCH_SUNXI) += lowlevel_init.o diff --git a/arch/arm/cpu/armv8/lowlevel_init.S b/arch/arm/cpu/armv8/lowlevel_init.S new file mode 100644 index 0000000..189e35f --- /dev/null +++ b/arch/arm/cpu/armv8/lowlevel_init.S @@ -0,0 +1,44 @@ +/* + * A lowlevel_init function that sets up the stack to call a C function to + * perform further init. + * + * SPDX-License-Identifier: GPL-2.0+ + */ + +#include <asm-offsets.h> +#include <config.h> +#include <linux/linkage.h> + +ENTRY(lowlevel_init) + /* + * Setup a temporary stack. Global data is not available yet. + */ +#if defined(CONFIG_SPL_BUILD) && defined(CONFIG_SPL_STACK) + ldr w0, =CONFIG_SPL_STACK +#else + ldr w0, =CONFIG_SYS_INIT_SP_ADDR +#endif + bic sp, x0, #0xf /* 16-byte alignment for ABI compliance */ + + /* + * Save the old LR(passed in x29) and the current LR to stack + */ + stp x29, x30, [sp, #-16]! + + /* + * Call the very early init function. This should do only the + * absolute bare minimum to get started. It should not: + * + * - set up DRAM + * - use global_data + * - clear BSS + * - try to start a console + * + * For boards with SPL this should be empty since SPL can do all of + * this init in the SPL board_init_f() function which is called + * immediately after this. + */ + bl s_init + ldp x29, x30, [sp] + ret +ENDPROC(lowlevel_init)