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authorAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
committerAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
commit57f0f512b273f60d52568b8c6b77e17f5636edc0 (patch)
tree5e910f0e82173f4ef4f51111366a3f1299037a7b /arch/cris/arch-v32/kernel/head.S
Initial import
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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.
+#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