| /* SPDX-License-Identifier: GPL-2.0 */ |
| /* |
| * CRISv32 kernel startup code. |
| * |
| * Copyright (C) 2003, Axis Communications AB |
| */ |
| |
| #include <linux/init.h> |
| |
| #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 |
| |
| __HEAD |
| 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. |
| __INIT |
| |
| _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 |
