diff options
Diffstat (limited to 'kernel/arch/cris/arch-v32/kernel/head.S')
| -rw-r--r-- | kernel/arch/cris/arch-v32/kernel/head.S | 440 |
1 files changed, 440 insertions, 0 deletions
diff --git a/kernel/arch/cris/arch-v32/kernel/head.S b/kernel/arch/cris/arch-v32/kernel/head.S new file mode 100644 index 000000000..74a66e0e3 --- /dev/null +++ b/kernel/arch/cris/arch-v32/kernel/head.S @@ -0,0 +1,440 @@ +/* + * CRISv32 kernel startup code. + * + * Copyright (C) 2003, Axis Communications AB + */ + +#define ASSEMBLER_MACROS_ONLY + +/* + * The macros found in mmu_defs_asm.h uses the ## concatenation operator, so + * -traditional must not be used when assembling this file. + */ +#include <arch/memmap.h> +#include <hwregs/reg_rdwr.h> +#include <hwregs/intr_vect.h> +#include <hwregs/asm/mmu_defs_asm.h> +#include <hwregs/asm/reg_map_asm.h> +#include <mach/startup.inc> + +#define CRAMFS_MAGIC 0x28cd3d45 +#define JHEAD_MAGIC 0x1FF528A6 +#define JHEAD_SIZE 8 +#define RAM_INIT_MAGIC 0x56902387 +#define COMMAND_LINE_MAGIC 0x87109563 +#define NAND_BOOT_MAGIC 0x9a9db001 + + ;; NOTE: R8 and R9 carry information from the decompressor (if the + ;; kernel was compressed). They must not be used in the code below + ;; until they are read! + + ;; Exported symbols. + .global etrax_irv + .global romfs_start + .global romfs_length + .global romfs_in_flash + .global nand_boot + .global swapper_pg_dir + + .text +tstart: + ;; This is the entry point of the kernel. The CPU is currently in + ;; supervisor mode. + ;; + ;; 0x00000000 if flash. + ;; 0x40004000 if DRAM. + ;; + di + + START_CLOCKS + + SETUP_WAIT_STATES + + GIO_INIT + + ;; Setup and enable the MMU. Use same configuration for both the data + ;; and the instruction MMU. + ;; + ;; Note; 3 cycles is needed for a bank-select to take effect. Further; + ;; bank 1 is the instruction MMU, bank 2 is the data MMU. + +#ifdef CONFIG_CRIS_MACH_ARTPEC3 + move.d REG_FIELD(mmu, rw_mm_kbase_hi, base_e, 8) \ + | REG_FIELD(mmu, rw_mm_kbase_hi, base_c, 4) \ + | REG_FIELD(mmu, rw_mm_kbase_hi, base_d, 5) \ + | REG_FIELD(mmu, rw_mm_kbase_hi, base_b, 0xb), $r0 +#else + move.d REG_FIELD(mmu, rw_mm_kbase_hi, base_e, 8) \ + | REG_FIELD(mmu, rw_mm_kbase_hi, base_c, 4) \ + | REG_FIELD(mmu, rw_mm_kbase_hi, base_b, 0xb), $r0 +#endif + + ;; Temporary map of 0x40 -> 0x40 and 0x00 -> 0x00. + move.d REG_FIELD(mmu, rw_mm_kbase_lo, base_4, 4) \ + | REG_FIELD(mmu, rw_mm_kbase_lo, base_0, 0), $r1 + + ;; Enable certain page protections and setup linear mapping + ;; for f,e,c,b,4,0. + + ;; ARTPEC-3: + ;; c,d used for linear kernel mapping, up to 512 MB + ;; e used for vmalloc + ;; f unused, but page mapped to get page faults + + ;; ETRAX FS: + ;; c used for linear kernel mapping, up to 256 MB + ;; d used for vmalloc + ;; e,f used for memory-mapped NOR flash + +#ifdef CONFIG_CRIS_MACH_ARTPEC3 + move.d REG_STATE(mmu, rw_mm_cfg, we, on) \ + | REG_STATE(mmu, rw_mm_cfg, acc, on) \ + | REG_STATE(mmu, rw_mm_cfg, ex, on) \ + | REG_STATE(mmu, rw_mm_cfg, inv, on) \ + | REG_STATE(mmu, rw_mm_cfg, seg_f, page) \ + | REG_STATE(mmu, rw_mm_cfg, seg_e, page) \ + | REG_STATE(mmu, rw_mm_cfg, seg_d, linear) \ + | REG_STATE(mmu, rw_mm_cfg, seg_c, linear) \ + | REG_STATE(mmu, rw_mm_cfg, seg_b, linear) \ + | REG_STATE(mmu, rw_mm_cfg, seg_a, page) \ + | REG_STATE(mmu, rw_mm_cfg, seg_9, page) \ + | REG_STATE(mmu, rw_mm_cfg, seg_8, page) \ + | REG_STATE(mmu, rw_mm_cfg, seg_7, page) \ + | REG_STATE(mmu, rw_mm_cfg, seg_6, page) \ + | REG_STATE(mmu, rw_mm_cfg, seg_5, page) \ + | REG_STATE(mmu, rw_mm_cfg, seg_4, linear) \ + | REG_STATE(mmu, rw_mm_cfg, seg_3, page) \ + | REG_STATE(mmu, rw_mm_cfg, seg_2, page) \ + | REG_STATE(mmu, rw_mm_cfg, seg_1, page) \ + | REG_STATE(mmu, rw_mm_cfg, seg_0, linear), $r2 +#else + move.d REG_STATE(mmu, rw_mm_cfg, we, on) \ + | REG_STATE(mmu, rw_mm_cfg, acc, on) \ + | REG_STATE(mmu, rw_mm_cfg, ex, on) \ + | REG_STATE(mmu, rw_mm_cfg, inv, on) \ + | REG_STATE(mmu, rw_mm_cfg, seg_f, linear) \ + | REG_STATE(mmu, rw_mm_cfg, seg_e, linear) \ + | REG_STATE(mmu, rw_mm_cfg, seg_d, page) \ + | REG_STATE(mmu, rw_mm_cfg, seg_c, linear) \ + | REG_STATE(mmu, rw_mm_cfg, seg_b, linear) \ + | REG_STATE(mmu, rw_mm_cfg, seg_a, page) \ + | REG_STATE(mmu, rw_mm_cfg, seg_9, page) \ + | REG_STATE(mmu, rw_mm_cfg, seg_8, page) \ + | REG_STATE(mmu, rw_mm_cfg, seg_7, page) \ + | REG_STATE(mmu, rw_mm_cfg, seg_6, page) \ + | REG_STATE(mmu, rw_mm_cfg, seg_5, page) \ + | REG_STATE(mmu, rw_mm_cfg, seg_4, linear) \ + | REG_STATE(mmu, rw_mm_cfg, seg_3, page) \ + | REG_STATE(mmu, rw_mm_cfg, seg_2, page) \ + | REG_STATE(mmu, rw_mm_cfg, seg_1, page) \ + | REG_STATE(mmu, rw_mm_cfg, seg_0, linear), $r2 +#endif + + ;; Update instruction MMU. + move 1, $srs + nop + nop + nop + move $r0, $s2 ; kbase_hi. + move $r1, $s1 ; kbase_lo. + move $r2, $s0 ; mm_cfg, virtual memory configuration. + + ;; Update data MMU. + move 2, $srs + nop + nop + nop + move $r0, $s2 ; kbase_hi. + move $r1, $s1 ; kbase_lo + move $r2, $s0 ; mm_cfg, virtual memory configuration. + + ;; Enable data and instruction MMU. + move 0, $srs + moveq 0xf, $r0 ; IMMU, DMMU, DCache, Icache on + nop + nop + nop + move $r0, $s0 + nop + nop + nop + + ; Check if starting from DRAM (network->RAM boot or unpacked + ; compressed kernel), or directly from flash. + lapcq ., $r0 + and.d 0x7fffffff, $r0 ; Mask off the non-cache bit. + cmp.d 0x10000, $r0 ; Arbitrary, something above this code. + blo _inflash0 + nop + + jump _inram ; Jump to cached RAM. + nop + + ;; Jumpgate. +_inflash0: + jump _inflash + nop + + ;; Put the following in a section so that storage for it can be + ;; reclaimed after init is finished. + .section ".init.text", "ax" + +_inflash: + + ;; Initialize DRAM. + cmp.d RAM_INIT_MAGIC, $r8 ; Already initialized? + beq _dram_initialized + nop + +#if defined CONFIG_ETRAXFS +#include "../mach-fs/dram_init.S" +#elif defined CONFIG_CRIS_MACH_ARTPEC3 +#include "../mach-a3/dram_init.S" +#else +#error Only ETRAXFS and ARTPEC-3 supported! +#endif + + +_dram_initialized: + ;; Copy the text and data section to DRAM. This depends on that the + ;; variables used below are correctly set up by the linker script. + ;; The calculated value stored in R4 is used below. + ;; Leave the cramfs file system (piggybacked after the kernel) in flash. + moveq 0, $r0 ; Source. + move.d text_start, $r1 ; Destination. + move.d __vmlinux_end, $r2 + move.d $r2, $r4 + sub.d $r1, $r4 +1: move.w [$r0+], $r3 + move.w $r3, [$r1+] + cmp.d $r2, $r1 + blo 1b + nop + + ;; Check for cramfs. + moveq 0, $r0 + move.d romfs_length, $r1 + move.d $r0, [$r1] + move.d [$r4], $r0 ; cramfs_super.magic + cmp.d CRAMFS_MAGIC, $r0 + bne 1f + nop + + ;; Set length and start of cramfs, set romfs_in_flash flag + addoq +4, $r4, $acr + move.d [$acr], $r0 + move.d romfs_length, $r1 + move.d $r0, [$r1] + add.d 0xf0000000, $r4 ; Add cached flash start in virtual memory. + move.d romfs_start, $r1 + move.d $r4, [$r1] +1: moveq 1, $r0 + move.d romfs_in_flash, $r1 + move.d $r0, [$r1] + + jump _start_it ; Jump to cached code. + nop + +_inram: + ;; Check if booting from NAND flash; if so, set appropriate flags + ;; and move on. + cmp.d NAND_BOOT_MAGIC, $r12 + bne move_cramfs ; not nand, jump + moveq 1, $r0 + move.d nand_boot, $r1 ; tell axisflashmap we're booting from NAND + move.d $r0, [$r1] + moveq 0, $r0 ; tell axisflashmap romfs is not in + move.d romfs_in_flash, $r1 ; (directly accessed) flash + move.d $r0, [$r1] + jump _start_it ; continue with boot + nop + +move_cramfs: + ;; kernel is in DRAM. + ;; Must figure out if there is a piggybacked rootfs image or not. + ;; Set romfs_length to 0 => no rootfs image available by default. + moveq 0, $r0 + move.d romfs_length, $r1 + move.d $r0, [$r1] + + ;; The kernel could have been unpacked to DRAM by the loader, but + ;; the cramfs image could still be in the flash immediately + ;; following the compressed kernel image. The loader passes the address + ;; of the byte succeeding the last compressed byte in the flash in + ;; register R9 when starting the kernel. + cmp.d 0x0ffffff8, $r9 + bhs _no_romfs_in_flash ; R9 points outside the flash area. + nop + ;; cramfs rootfs might to be in flash. Check for it. + move.d [$r9], $r0 ; cramfs_super.magic + cmp.d CRAMFS_MAGIC, $r0 + bne _no_romfs_in_flash + nop + + ;; found cramfs in flash. set address and size, and romfs_in_flash flag. + addoq +4, $r9, $acr + move.d [$acr], $r0 + move.d romfs_length, $r1 + move.d $r0, [$r1] + add.d 0xf0000000, $r9 ; Add cached flash start in virtual memory. + move.d romfs_start, $r1 + move.d $r9, [$r1] + moveq 1, $r0 + move.d romfs_in_flash, $r1 + move.d $r0, [$r1] + + jump _start_it ; Jump to cached code. + nop + +_no_romfs_in_flash: + ;; No romfs in flash, so look for cramfs, or jffs2 with jhead, + ;; after kernel in RAM, as is the case with network->RAM boot. + ;; For cramfs, partition starts with magic and length. + ;; For jffs2, a jhead is prepended which contains with magic and length. + ;; The jhead is not part of the jffs2 partition however. +#ifndef CONFIG_ETRAXFS_SIM + move.d __bss_start, $r0 +#else + move.d __end, $r0 +#endif + move.d [$r0], $r1 + cmp.d CRAMFS_MAGIC, $r1 ; cramfs magic? + beq 2f ; yes, jump + nop + cmp.d JHEAD_MAGIC, $r1 ; jffs2 (jhead) magic? + bne 4f ; no, skip copy + nop + addq 4, $r0 ; location of jffs2 size + move.d [$r0+], $r2 ; fetch jffs2 size -> r2 + ; r0 now points to start of jffs2 + ba 3f + nop +2: + addoq +4, $r0, $acr ; location of cramfs size + move.d [$acr], $r2 ; fetch cramfs size -> r2 + ; r0 still points to start of cramfs +3: + ;; Now, move the root fs to after kernel's BSS + + move.d _end, $r1 ; start of cramfs -> r1 + move.d romfs_start, $r3 + move.d $r1, [$r3] ; store at romfs_start (for axisflashmap) + move.d romfs_length, $r3 + move.d $r2, [$r3] ; store size at romfs_length + + add.d $r2, $r0 ; copy from end and downwards + add.d $r2, $r1 + + lsrq 1, $r2 ; Size is in bytes, we copy words. + addq 1, $r2 +1: + move.w [$r0], $r3 + move.w $r3, [$r1] + subq 2, $r0 + subq 2, $r1 + subq 1, $r2 + bne 1b + nop + +4: + ;; BSS move done. + ;; Clear romfs_in_flash flag, as we now know romfs is in DRAM + ;; Also clear nand_boot flag; if we got here, we know we've not + ;; booted from NAND flash. + moveq 0, $r0 + move.d romfs_in_flash, $r1 + move.d $r0, [$r1] + moveq 0, $r0 + move.d nand_boot, $r1 + move.d $r0, [$r1] + + jump _start_it ; Jump to cached code. + nop + +_start_it: + + ;; Check if kernel command line is supplied + cmp.d COMMAND_LINE_MAGIC, $r10 + bne no_command_line + nop + + move.d 256, $r13 + move.d cris_command_line, $r10 + or.d 0x80000000, $r11 ; Make it virtual +1: + move.b [$r11+], $r1 + move.b $r1, [$r10+] + subq 1, $r13 + bne 1b + nop + +no_command_line: + + ;; The kernel stack contains a task structure for each task. This + ;; the initial kernel stack is in the same page as the init_task, + ;; but starts at the top of the page, i.e. + 8192 bytes. + move.d init_thread_union + 8192, $sp + move.d ebp_start, $r0 ; Defined in linker-script. + move $r0, $ebp + move.d etrax_irv, $r1 ; Set the exception base register and pointer. + move.d $r0, [$r1] + + ;; Clear the BSS region from _bss_start to _end. + move.d __bss_start, $r0 + move.d _end, $r1 +1: clear.d [$r0+] + cmp.d $r1, $r0 + blo 1b + nop + + ; Initialize registers to increase determinism + move.d __bss_start, $r0 + movem [$r0], $r13 + +#ifdef CONFIG_ETRAX_L2CACHE + jsr l2cache_init + nop +#endif + + jump start_kernel ; Jump to start_kernel() in init/main.c. + nop + + .data +etrax_irv: + .dword 0 + +; Variables for communication with the Axis flash map driver (axisflashmap), +; and for setting up memory in arch/cris/kernel/setup.c . + +; romfs_start is set to the start of the root file system, if it exists +; in directly accessible memory (i.e. NOR Flash when booting from Flash, +; or RAM when booting directly from a network-downloaded RAM image) +romfs_start: + .dword 0 + +; romfs_length is set to the size of the root file system image, if it exists +; in directly accessible memory (see romfs_start). Otherwise it is set to 0. +romfs_length: + .dword 0 + +; romfs_in_flash is set to 1 if the root file system resides in directly +; accessible flash memory (i.e. NOR flash). It is set to 0 for RAM boot +; or NAND flash boot. +romfs_in_flash: + .dword 0 + +; nand_boot is set to 1 when the kernel has been booted from NAND flash +nand_boot: + .dword 0 + +swapper_pg_dir = 0xc0002000 + + .section ".init.data", "aw" + +#if defined CONFIG_ETRAXFS +#include "../mach-fs/hw_settings.S" +#elif defined CONFIG_CRIS_MACH_ARTPEC3 +#include "../mach-a3/hw_settings.S" +#else +#error Only ETRAXFS and ARTPEC-3 supported! +#endif |