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|
/*
* 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.
move.d __bss_start, $r0
move.d [$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
|
