diff options
Diffstat (limited to 'arch/microblaze/kernel/head.S')
| -rw-r--r-- | arch/microblaze/kernel/head.S | 45 |
1 files changed, 28 insertions, 17 deletions
diff --git a/arch/microblaze/kernel/head.S b/arch/microblaze/kernel/head.S index 42434008209..77320b8fc16 100644 --- a/arch/microblaze/kernel/head.S +++ b/arch/microblaze/kernel/head.S @@ -39,7 +39,7 @@ #include <asm/mmu.h> #include <asm/processor.h> -.data +.section .data .global empty_zero_page .align 12 empty_zero_page: @@ -50,6 +50,11 @@ swapper_pg_dir: #endif /* CONFIG_MMU */ +.section .rodata +.align 4 +endian_check: + .word 1 + __HEAD ENTRY(_start) #if CONFIG_KERNEL_BASE_ADDR == 0 @@ -62,23 +67,29 @@ real_start: andi r1, r1, ~2 mts rmsr, r1 /* - * Here is checking mechanism which check if Microblaze has msr instructions - * We load msr and compare it with previous r1 value - if is the same, - * msr instructions works if not - cpu don't have them. + * According to Xilinx, msrclr instruction behaves like 'mfs rX,rpc' + * if the msrclr instruction is not enabled. We use this to detect + * if the opcode is available, by issuing msrclr and then testing the result. + * r8 == 0 - msr instructions are implemented + * r8 != 0 - msr instructions are not implemented */ - /* r8=0 - I have msr instr, 1 - I don't have them */ - rsubi r0, r0, 1 /* set the carry bit */ - msrclr r0, 0x4 /* try to clear it */ - /* read the carry bit, r8 will be '0' if msrclr exists */ - addik r8, r0, 0 + msrclr r8, 0 /* clear nothing - just read msr for test */ + cmpu r8, r8, r1 /* r1 must contain msr reg content */ /* r7 may point to an FDT, or there may be one linked in. if it's in r7, we've got to save it away ASAP. We ensure r7 points to a valid FDT, just in case the bootloader is broken or non-existent */ beqi r7, no_fdt_arg /* NULL pointer? don't copy */ - lw r11, r0, r7 /* Does r7 point to a */ - rsubi r11, r11, OF_DT_HEADER /* valid FDT? */ +/* Does r7 point to a valid FDT? Load HEADER magic number */ + /* Run time Big/Little endian platform */ + /* Save 1 as word and load byte - 0 - BIG, 1 - LITTLE */ + lbui r11, r0, TOPHYS(endian_check) + beqid r11, big_endian /* DO NOT break delay stop dependency */ + lw r11, r0, r7 /* Big endian load in delay slot */ + lwr r11, r0, r7 /* Little endian load */ +big_endian: + rsubi r11, r11, OF_DT_HEADER /* Check FDT header */ beqi r11, _prepare_copy_fdt or r7, r0, r0 /* clear R7 when not valid DTB */ bnei r11, no_fdt_arg /* No - get out of here */ @@ -213,26 +224,26 @@ start_here: #endif /* CONFIG_MMU */ /* Initialize small data anchors */ - la r13, r0, _KERNEL_SDA_BASE_ - la r2, r0, _KERNEL_SDA2_BASE_ + addik r13, r0, _KERNEL_SDA_BASE_ + addik r2, r0, _KERNEL_SDA2_BASE_ /* Initialize stack pointer */ - la r1, r0, init_thread_union + THREAD_SIZE - 4 + addik r1, r0, init_thread_union + THREAD_SIZE - 4 /* Initialize r31 with current task address */ - la r31, r0, init_task + addik r31, r0, init_task /* * Call platform dependent initialize function. * Please see $(ARCH)/mach-$(SUBARCH)/setup.c for * the function. */ - la r9, r0, machine_early_init + addik r9, r0, machine_early_init brald r15, r9 nop #ifndef CONFIG_MMU - la r15, r0, machine_halt + addik r15, r0, machine_halt braid start_kernel nop #else |