This adds a new Kconfig option CONFIG_MIPS_INIT_STACK_IN_SRAM which a SoC can select if it supports some kind of SRAM. Together with CONFIG_SYS_INIT_SP_ADDR the initial stack and global data can be set up in that SRAM. This can be used to provide a C environment also for lowlevel_init().
Signed-off-by: Daniel Schwierzeck daniel.schwierzeck@gmail.com ---
arch/mips/Kconfig | 11 +++++++++++ arch/mips/cpu/start.S | 7 +++++++ 2 files changed, 18 insertions(+)
diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig index 709ac5c..d97930e 100644 --- a/arch/mips/Kconfig +++ b/arch/mips/Kconfig @@ -302,6 +302,17 @@ config SWAP_IO_SPACE config SYS_MIPS_CACHE_INIT_RAM_LOAD bool
+config MIPS_INIT_STACK_IN_SRAM + bool + default n + help + Select this if the initial stack frame could be setup in SRAM. + Normally the initial stack frame is set up in DRAM which is often + only available after lowlevel_init. With this option the initial + stack frame and the early C environment is set up before + lowlevel_init. Thus lowlevel_init does not need to be implemented + in assembler. + config SYS_DCACHE_SIZE int default 0 diff --git a/arch/mips/cpu/start.S b/arch/mips/cpu/start.S index ee9de99..3af571c 100644 --- a/arch/mips/cpu/start.S +++ b/arch/mips/cpu/start.S @@ -226,6 +226,11 @@ wr_done: nop #endif
+#ifdef CONFIG_MIPS_INIT_STACK_IN_SRAM + /* Set up initial stack and global data */ + setup_stack_gd +#endif + #ifndef CONFIG_SKIP_LOWLEVEL_INIT # ifdef CONFIG_SYS_MIPS_CACHE_INIT_RAM_LOAD /* Initialize any external memory */ @@ -247,8 +252,10 @@ wr_done: # endif #endif
+#ifndef CONFIG_MIPS_INIT_STACK_IN_SRAM /* Set up initial stack and global data */ setup_stack_gd +#endif
move a0, zero # a0 <-- boot_flags = 0 PTR_LA t9, board_init_f