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diff --git a/arch/cris/arch-v32/kernel/head.S b/arch/cris/arch-v32/kernel/head.S
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+/*
+ * CRISv32 kernel startup code.
+ *
+ * Copyright (C) 2003, Axis Communications AB
+ */
+
+#include <linux/config.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 <asm/arch/hwregs/reg_rdwr.h>
+#include <asm/arch/hwregs/asm/mmu_defs_asm.h>
+#include <asm/arch/hwregs/asm/reg_map_asm.h>
+#include <asm/arch/hwregs/asm/config_defs_asm.h>
+#include <asm/arch/hwregs/asm/bif_core_defs_asm.h>
+
+#define CRAMFS_MAGIC 0x28cd3d45
+#define RAM_INIT_MAGIC 0x56902387
+#define COMMAND_LINE_MAGIC 0x87109563
+
+ ;; 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 swapper_pg_dir
+ .global crisv32_nand_boot
+ .global crisv32_nand_cramfs_offset
+
+ ;; Dummy section to make it bootable with current VCS simulator
+#ifdef CONFIG_ETRAXFS_SIM
+ .section ".boot", "ax"
+ ba tstart
+ nop
+#endif
+
+ .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 for used blocks.
+ move.d REG_ADDR(config, regi_config, rw_clk_ctrl), $r1
+ move.d [$r1], $r0
+ or.d REG_STATE(config, rw_clk_ctrl, cpu, yes) | \
+ REG_STATE(config, rw_clk_ctrl, bif, yes) | \
+ REG_STATE(config, rw_clk_ctrl, fix_io, yes), $r0
+ move.d $r0, [$r1]
+
+ ;; Set up waitstates etc
+ move.d REG_ADDR(bif_core, regi_bif_core, rw_grp1_cfg), $r0
+ move.d CONFIG_ETRAX_MEM_GRP1_CONFIG, $r1
+ move.d $r1, [$r0]
+ move.d REG_ADDR(bif_core, regi_bif_core, rw_grp2_cfg), $r0
+ move.d CONFIG_ETRAX_MEM_GRP2_CONFIG, $r1
+ move.d $r1, [$r0]
+ move.d REG_ADDR(bif_core, regi_bif_core, rw_grp3_cfg), $r0
+ move.d CONFIG_ETRAX_MEM_GRP3_CONFIG, $r1
+ move.d $r1, [$r0]
+ move.d REG_ADDR(bif_core, regi_bif_core, rw_grp4_cfg), $r0
+ move.d CONFIG_ETRAX_MEM_GRP4_CONFIG, $r1
+ move.d $r1, [$r0]
+
+#ifdef CONFIG_ETRAXFS_SIM
+ ;; Set up minimal flash waitstates
+ move.d 0, $r10
+ move.d REG_ADDR(bif_core, regi_bif_core, rw_grp1_cfg), $r11
+ move.d $r10, [$r11]
+#endif
+
+ ;; 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.
+#ifndef CONFIG_ETRAXFS_SIM
+ 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
+#else
+ ;; Map the virtual DRAM to the RW eprom area at address 0.
+ ;; Also map 0xa for the hook calls,
+ move.d REG_FIELD(mmu, rw_mm_kbase_hi, base_e, 8) \
+ | REG_FIELD(mmu, rw_mm_kbase_hi, base_c, 0) \
+ | REG_FIELD(mmu, rw_mm_kbase_hi, base_b, 0xb) \
+ | REG_FIELD(mmu, rw_mm_kbase_hi, base_a, 0xa), $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.
+#ifndef CONFIG_ETRAXFS_SIM
+ 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
+#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, linear) \
+ | 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
+
+#ifdef CONFIG_SMP
+ ;; Read CPU ID
+ move 0, $srs
+ nop
+ nop
+ nop
+ move $s10, $r0
+ cmpq 0, $r0
+ beq master_cpu
+ nop
+slave_cpu:
+ ; A slave waits for cpu_now_booting to be equal to CPU ID.
+ move.d cpu_now_booting, $r1
+slave_wait:
+ cmp.d [$r1], $r0
+ bne slave_wait
+ nop
+ ; Time to boot-up. Get stack location provided by master CPU.
+ move.d smp_init_current_idle_thread, $r1
+ move.d [$r1], $sp
+ add.d 8192, $sp
+ move.d ebp_start, $r0 ; Defined in linker-script.
+ move $r0, $ebp
+ jsr smp_callin
+ nop
+master_cpu:
+#endif
+#ifndef CONFIG_ETRAXFS_SIM
+ ;; Check if starting from DRAM or 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
+#endif
+
+ 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
+
+#include "../lib/dram_init.S"
+
+_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.
+ 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
+
+ ;; Keep CRAMFS in flash.
+ 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
+
+ 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 (in that case we just remember the offset
+ ;; into the flash where cramfs should be).
+ move.d REG_ADDR(config, regi_config, r_bootsel), $r0
+ move.d [$r0], $r0
+ and.d REG_MASK(config, r_bootsel, boot_mode), $r0
+ cmp.d REG_STATE(config, r_bootsel, boot_mode, nand), $r0
+ bne move_cramfs
+ moveq 1,$r0
+ move.d crisv32_nand_boot, $r1
+ move.d $r0, [$r1]
+ move.d crisv32_nand_cramfs_offset, $r1
+ move.d $r9, [$r1]
+ moveq 1, $r0
+ move.d romfs_in_flash, $r1
+ move.d $r0, [$r1]
+ jump _start_it
+ nop
+
+move_cramfs:
+ ;; Move the cramfs after BSS.
+ moveq 0, $r0
+ move.d romfs_length, $r1
+ move.d $r0, [$r1]
+
+#ifndef CONFIG_ETRAXFS_SIM
+ ;; The kernel could have been unpacked to DRAM by the loader, but
+ ;; the cramfs image could still be inte the flash immediately
+ ;; following the compressed kernel image. The loaded passes the address
+ ;; of the bute succeeding the last compressed byte in the flash in
+ ;; register R9 when starting the kernel.
+ cmp.d 0x0ffffff8, $r9
+ bhs _no_romfs_in_flash ; R9 points outside the flash area.
+ nop
+#else
+ ba _no_romfs_in_flash
+ nop
+#endif
+ move.d [$r9], $r0 ; cramfs_super.magic
+ cmp.d CRAMFS_MAGIC, $r0
+ bne _no_romfs_in_flash
+ nop
+
+ 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:
+ ;; Look for cramfs.
+#ifndef CONFIG_ETRAXFS_SIM
+ move.d __vmlinux_end, $r0
+#else
+ move.d __end, $r0
+#endif
+ move.d [$r0], $r1
+ cmp.d CRAMFS_MAGIC, $r1
+ bne 2f
+ nop
+
+ addoq +4, $r0, $acr
+ move.d [$acr], $r2
+ move.d _end, $r1
+ move.d romfs_start, $r3
+ move.d $r1, [$r3]
+ move.d romfs_length, $r3
+ move.d $r2, [$r3]
+
+#ifndef CONFIG_ETRAXFS_SIM
+ add.d $r2, $r0
+ 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
+#endif
+
+2:
+ moveq 0, $r0
+ move.d romfs_in_flash, $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+], $r12
+ move.b $r12, [$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]
+
+#ifndef CONFIG_ETRAXFS_SIM
+ ;; 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
+#endif
+
+#ifdef CONFIG_ETRAXFS_SIM
+ /* Set the watchdog timeout to something big. Will be removed when */
+ /* watchdog can be disabled with command line option */
+ move.d 0x7fffffff, $r10
+ jsr CPU_WATCHDOG_TIMEOUT
+ nop
+#endif
+
+ ; Initialize registers to increase determinism
+ move.d __bss_start, $r0
+ movem [$r0], $r13
+
+ jump start_kernel ; Jump to start_kernel() in init/main.c.
+ nop
+
+ .data
+etrax_irv:
+ .dword 0
+romfs_start:
+ .dword 0
+romfs_length:
+ .dword 0
+romfs_in_flash:
+ .dword 0
+crisv32_nand_boot:
+ .dword 0
+crisv32_nand_cramfs_offset:
+ .dword 0
+
+swapper_pg_dir = 0xc0002000
+
+ .section ".init.data", "aw"
+
+#include "../lib/hw_settings.S"
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.