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-rw-r--r--arch/riscv/cpu/nx25/start.S291
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diff --git a/arch/riscv/cpu/nx25/start.S b/arch/riscv/cpu/nx25/start.S
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+/*
+ * Startup Code for RISC-V Core
+ *
+ * Copyright (c) 2017 Microsemi Corporation.
+ * Copyright (c) 2017 Padmarao Begari <Padmarao.Begari@microsemi.com>
+ *
+ * Copyright (C) 2017 Andes Technology Corporation
+ * Rick Chen, Andes Technology Corporation <rick@andestech.com>
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+
+#include <asm-offsets.h>
+#include <config.h>
+#include <common.h>
+#include <elf.h>
+#include <asm/encoding.h>
+
+#ifdef CONFIG_32BIT
+#define LREG lw
+#define SREG sw
+#define REGBYTES 4
+#define RELOC_TYPE R_RISCV_32
+#define SYM_INDEX 0x8
+#define SYM_SIZE 0x10
+#else
+#define LREG ld
+#define SREG sd
+#define REGBYTES 8
+#define RELOC_TYPE R_RISCV_64
+#define SYM_INDEX 0x20
+#define SYM_SIZE 0x18
+#endif
+
+.section .text
+.globl _start
+_start:
+ j handle_reset
+
+nmi_vector:
+ j nmi_vector
+
+trap_vector:
+ j trap_entry
+
+.global trap_entry
+handle_reset:
+ la t0, trap_entry
+ csrw mtvec, t0
+ csrwi mstatus, 0
+ csrwi mie, 0
+
+/*
+ * Do CPU critical regs init only at reboot,
+ * not when booting from ram
+ */
+#ifdef CONFIG_INIT_CRITICAL
+ jal cpu_init_crit /* Do CPU critical regs init */
+#endif
+
+/*
+ * Set stackpointer in internal/ex RAM to call board_init_f
+ */
+call_board_init_f:
+ li t0, -16
+ li t1, CONFIG_SYS_INIT_SP_ADDR
+ and sp, t1, t0 /* force 16 byte alignment */
+
+#ifdef CONFIG_DEBUG_UART
+ jal debug_uart_init
+#endif
+
+call_board_init_f_0:
+ mv a0, sp
+ jal board_init_f_alloc_reserve
+ mv sp, a0
+ jal board_init_f_init_reserve
+
+ mv a0, zero /* a0 <-- boot_flags = 0 */
+ la t5, board_init_f
+ jr t5 /* jump to board_init_f() */
+
+/*
+ * void relocate_code (addr_sp, gd, addr_moni)
+ *
+ * This "function" does not return, instead it continues in RAM
+ * after relocating the monitor code.
+ *
+ */
+.globl relocate_code
+relocate_code:
+ mv s2, a0 /* save addr_sp */
+ mv s3, a1 /* save addr of gd */
+ mv s4, a2 /* save addr of destination */
+
+/*
+ *Set up the stack
+ */
+stack_setup:
+ mv sp, s2
+ la t0, _start
+ sub t6, s4, t0 /* t6 <- relocation offset */
+ beq t0, s4, clear_bss /* skip relocation */
+
+ mv t1, s4 /* t1 <- scratch for copy_loop */
+ la t3, __bss_start
+ sub t3, t3, t0 /* t3 <- __bss_start_ofs */
+ add t2, t0, t3 /* t2 <- source end address */
+
+copy_loop:
+ LREG t5, 0(t0)
+ addi t0, t0, REGBYTES
+ SREG t5, 0(t1)
+ addi t1, t1, REGBYTES
+ blt t0, t2, copy_loop
+
+/*
+ * Update dynamic relocations after board_init_f
+ */
+fix_rela_dyn:
+ la t1, __rel_dyn_start
+ la t2, __rel_dyn_end
+ beq t1, t2, clear_bss
+ add t1, t1, t6 /* t1 <- rela_dyn_start in RAM */
+ add t2, t2, t6 /* t2 <- rela_dyn_end in RAM */
+
+/*
+ * skip first reserved entry: address, type, addend
+ */
+ bne t1, t2, 7f
+
+6:
+ LREG t5, -(REGBYTES*2)(t1) /* t5 <-- relocation info:type */
+ li t3, R_RISCV_RELATIVE /* reloc type R_RISCV_RELATIVE */
+ bne t5, t3, 8f /* skip non-RISCV_RELOC entries */
+ LREG t3, -(REGBYTES*3)(t1)
+ LREG t5, -(REGBYTES)(t1) /* t5 <-- addend */
+ add t5, t5, t6 /* t5 <-- location to fix up in RAM */
+ add t3, t3, t6 /* t3 <-- location to fix up in RAM */
+ SREG t5, 0(t3)
+7:
+ addi t1, t1, (REGBYTES*3)
+ ble t1, t2, 6b
+
+8:
+ la t4, __dyn_sym_start
+ add t4, t4, t6
+
+9:
+ LREG t5, -(REGBYTES*2)(t1) /* t5 <-- relocation info:type */
+ srli t0, t5, SYM_INDEX /* t0 <--- sym table index */
+ andi t5, t5, 0xFF /* t5 <--- relocation type */
+ li t3, RELOC_TYPE
+ bne t5, t3, 10f /* skip non-addned entries */
+
+ LREG t3, -(REGBYTES*3)(t1)
+ li t5, SYM_SIZE
+ mul t0, t0, t5
+ add s1, t4, t0
+ LREG t5, REGBYTES(s1)
+ add t5, t5, t6 /* t5 <-- location to fix up in RAM */
+ add t3, t3, t6 /* t3 <-- location to fix up in RAM */
+ SREG t5, 0(t3)
+10:
+ addi t1, t1, (REGBYTES*3)
+ ble t1, t2, 9b
+
+/*
+ * trap update
+*/
+ la t0, trap_entry
+ add t0, t0, t6
+ csrw mtvec, t0
+
+clear_bss:
+ la t0, __bss_start /* t0 <- rel __bss_start in FLASH */
+ add t0, t0, t6 /* t0 <- rel __bss_start in RAM */
+ la t1, __bss_end /* t1 <- rel __bss_end in FLASH */
+ add t1, t1, t6 /* t1 <- rel __bss_end in RAM */
+ li t2, 0x00000000 /* clear */
+ beq t0, t1, call_board_init_r
+
+clbss_l:
+ SREG t2, 0(t0) /* clear loop... */
+ addi t0, t0, REGBYTES
+ bne t0, t1, clbss_l
+
+/*
+ * We are done. Do not return, instead branch to second part of board
+ * initialization, now running from RAM.
+ */
+call_board_init_r:
+ la t0, board_init_r
+ mv t4, t0 /* offset of board_init_r() */
+ add t4, t4, t6 /* real address of board_init_r() */
+/*
+ * setup parameters for board_init_r
+ */
+ mv a0, s3 /* gd_t */
+ mv a1, s4 /* dest_addr */
+
+/*
+ * jump to it ...
+ */
+ jr t4 /* jump to board_init_r() */
+
+/*
+ * trap entry
+ */
+trap_entry:
+ addi sp, sp, -32*REGBYTES
+ SREG x1, 1*REGBYTES(sp)
+ SREG x2, 2*REGBYTES(sp)
+ SREG x3, 3*REGBYTES(sp)
+ SREG x4, 4*REGBYTES(sp)
+ SREG x5, 5*REGBYTES(sp)
+ SREG x6, 6*REGBYTES(sp)
+ SREG x7, 7*REGBYTES(sp)
+ SREG x8, 8*REGBYTES(sp)
+ SREG x9, 9*REGBYTES(sp)
+ SREG x10, 10*REGBYTES(sp)
+ SREG x11, 11*REGBYTES(sp)
+ SREG x12, 12*REGBYTES(sp)
+ SREG x13, 13*REGBYTES(sp)
+ SREG x14, 14*REGBYTES(sp)
+ SREG x15, 15*REGBYTES(sp)
+ SREG x16, 16*REGBYTES(sp)
+ SREG x17, 17*REGBYTES(sp)
+ SREG x18, 18*REGBYTES(sp)
+ SREG x19, 19*REGBYTES(sp)
+ SREG x20, 20*REGBYTES(sp)
+ SREG x21, 21*REGBYTES(sp)
+ SREG x22, 22*REGBYTES(sp)
+ SREG x23, 23*REGBYTES(sp)
+ SREG x24, 24*REGBYTES(sp)
+ SREG x25, 25*REGBYTES(sp)
+ SREG x26, 26*REGBYTES(sp)
+ SREG x27, 27*REGBYTES(sp)
+ SREG x28, 28*REGBYTES(sp)
+ SREG x29, 29*REGBYTES(sp)
+ SREG x30, 30*REGBYTES(sp)
+ SREG x31, 31*REGBYTES(sp)
+ csrr a0, mcause
+ csrr a1, mepc
+ mv a2, sp
+ jal handle_trap
+ csrw mepc, a0
+
+/*
+ * Remain in M-mode after mret
+ */
+ li t0, MSTATUS_MPP
+ csrs mstatus, t0
+ LREG x1, 1*REGBYTES(sp)
+ LREG x2, 2*REGBYTES(sp)
+ LREG x3, 3*REGBYTES(sp)
+ LREG x4, 4*REGBYTES(sp)
+ LREG x5, 5*REGBYTES(sp)
+ LREG x6, 6*REGBYTES(sp)
+ LREG x7, 7*REGBYTES(sp)
+ LREG x8, 8*REGBYTES(sp)
+ LREG x9, 9*REGBYTES(sp)
+ LREG x10, 10*REGBYTES(sp)
+ LREG x11, 11*REGBYTES(sp)
+ LREG x12, 12*REGBYTES(sp)
+ LREG x13, 13*REGBYTES(sp)
+ LREG x14, 14*REGBYTES(sp)
+ LREG x15, 15*REGBYTES(sp)
+ LREG x16, 16*REGBYTES(sp)
+ LREG x17, 17*REGBYTES(sp)
+ LREG x18, 18*REGBYTES(sp)
+ LREG x19, 19*REGBYTES(sp)
+ LREG x20, 20*REGBYTES(sp)
+ LREG x21, 21*REGBYTES(sp)
+ LREG x22, 22*REGBYTES(sp)
+ LREG x23, 23*REGBYTES(sp)
+ LREG x24, 24*REGBYTES(sp)
+ LREG x25, 25*REGBYTES(sp)
+ LREG x26, 26*REGBYTES(sp)
+ LREG x27, 27*REGBYTES(sp)
+ LREG x28, 28*REGBYTES(sp)
+ LREG x29, 29*REGBYTES(sp)
+ LREG x30, 30*REGBYTES(sp)
+ LREG x31, 31*REGBYTES(sp)
+ addi sp, sp, 32*REGBYTES
+ mret
+
+#ifdef CONFIG_INIT_CRITICAL
+cpu_init_crit:
+ ret
+#endif