This patch adds the kernel booting and the initial setup code. Signed-off-by: Ley Foon Tan <lftan@xxxxxxxxxx> --- arch/nios2/include/asm/entry.h | 120 ++++++++++++++++++++++ arch/nios2/include/asm/setup.h | 38 +++++++ arch/nios2/kernel/head.S | 175 ++++++++++++++++++++++++++++++++ arch/nios2/kernel/setup.c | 218 ++++++++++++++++++++++++++++++++++++++++ 4 files changed, 551 insertions(+), 0 deletions(-) create mode 100644 arch/nios2/include/asm/entry.h create mode 100644 arch/nios2/include/asm/setup.h create mode 100644 arch/nios2/kernel/head.S create mode 100644 arch/nios2/kernel/setup.c diff --git a/arch/nios2/include/asm/entry.h b/arch/nios2/include/asm/entry.h new file mode 100644 index 0000000..cf37f55 --- /dev/null +++ b/arch/nios2/include/asm/entry.h @@ -0,0 +1,120 @@ +/* + * Copyright (C) 2010 Tobias Klauser <tklauser@xxxxxxxxxx> + * Copyright (C) 2004 Microtronix Datacom Ltd. + * + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file "COPYING" in the main directory of this archive + * for more details. + */ + +#ifndef _ASM_NIOS2_ENTRY_H +#define _ASM_NIOS2_ENTRY_H + +#ifdef __ASSEMBLY__ + +#include <asm/processor.h> +#include <asm/registers.h> +#include <asm/asm-offsets.h> + +/* + * Standard Nios2 interrupt entry and exit macros. + * Must be called with interrupts disabled. + */ +.macro SAVE_ALL + rdctl r24, estatus + andi r24, r24, ESTATUS_EU + beq r24, r0, 1f /* In supervisor mode, already on kernel stack */ + + movia r24, _current_thread /* Switch to current kernel stack */ + ldw r24, 0(r24) /* using the thread_info */ + addi r24, r24, THREAD_SIZE-PT_REGS_SIZE + stw sp, PT_SP(r24) /* Save user stack before changing */ + mov sp, r24 + br 2f + +1 : mov r24, sp + addi sp, sp, -PT_REGS_SIZE /* Backup the kernel stack pointer */ + stw r24, PT_SP(sp) +2 : stw r1, PT_R1(sp) + stw r2, PT_R2(sp) + stw r3, PT_R3(sp) + stw r4, PT_R4(sp) + stw r5, PT_R5(sp) + stw r6, PT_R6(sp) + stw r7, PT_R7(sp) + stw r8, PT_R8(sp) + stw r9, PT_R9(sp) + stw r10, PT_R10(sp) + stw r11, PT_R11(sp) + stw r12, PT_R12(sp) + stw r13, PT_R13(sp) + stw r14, PT_R14(sp) + stw r15, PT_R15(sp) + stw r2, PT_ORIG_R2(sp) + stw r7, PT_ORIG_R7(sp) + + stw ra, PT_RA(sp) + stw fp, PT_FP(sp) + stw gp, PT_GP(sp) + rdctl r24, estatus + stw r24, PT_ESTATUS(sp) + stw ea, PT_EA(sp) +.endm + +.macro RESTORE_ALL + ldw r1, PT_R1(sp) /* Restore registers */ + ldw r2, PT_R2(sp) + ldw r3, PT_R3(sp) + ldw r4, PT_R4(sp) + ldw r5, PT_R5(sp) + ldw r6, PT_R6(sp) + ldw r7, PT_R7(sp) + ldw r8, PT_R8(sp) + ldw r9, PT_R9(sp) + ldw r10, PT_R10(sp) + ldw r11, PT_R11(sp) + ldw r12, PT_R12(sp) + ldw r13, PT_R13(sp) + ldw r14, PT_R14(sp) + ldw r15, PT_R15(sp) + ldw ra, PT_RA(sp) + ldw fp, PT_FP(sp) + ldw gp, PT_GP(sp) + ldw r24, PT_ESTATUS(sp) + wrctl estatus, r24 + ldw ea, PT_EA(sp) + ldw sp, PT_SP(sp) /* Restore sp last */ +.endm + +.macro SAVE_SWITCH_STACK + addi sp, sp, -SWITCH_STACK_SIZE + stw r16, SW_R16(sp) + stw r17, SW_R17(sp) + stw r18, SW_R18(sp) + stw r19, SW_R19(sp) + stw r20, SW_R20(sp) + stw r21, SW_R21(sp) + stw r22, SW_R22(sp) + stw r23, SW_R23(sp) + stw fp, SW_FP(sp) + stw gp, SW_GP(sp) + stw ra, SW_RA(sp) +.endm + +.macro RESTORE_SWITCH_STACK + ldw r16, SW_R16(sp) + ldw r17, SW_R17(sp) + ldw r18, SW_R18(sp) + ldw r19, SW_R19(sp) + ldw r20, SW_R20(sp) + ldw r21, SW_R21(sp) + ldw r22, SW_R22(sp) + ldw r23, SW_R23(sp) + ldw fp, SW_FP(sp) + ldw gp, SW_GP(sp) + ldw ra, SW_RA(sp) + addi sp, sp, SWITCH_STACK_SIZE +.endm + +#endif /* __ASSEMBLY__ */ +#endif /* _ASM_NIOS2_ENTRY_H */ diff --git a/arch/nios2/include/asm/setup.h b/arch/nios2/include/asm/setup.h new file mode 100644 index 0000000..a3e05a7 --- /dev/null +++ b/arch/nios2/include/asm/setup.h @@ -0,0 +1,38 @@ +/* + * Copyright (C) 2011 Tobias Klauser <tklauser@xxxxxxxxxx> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + * + */ + +#ifndef _ASM_NIOS2_SETUP_H +#define _ASM_NIOS2_SETUP_H + +#include <asm-generic/setup.h> + +#ifndef __ASSEMBLY__ +# ifdef __KERNEL__ + +extern char exception_handler_hook[]; +extern char fast_handler[]; +extern char fast_handler_end[]; + +extern void pagetable_init(void); + +extern void setup_early_printk(void); + +# endif/* __KERNEL__ */ +#endif /* __ASSEMBLY__ */ + +#endif /* _ASM_NIOS2_SETUP_H */ diff --git a/arch/nios2/kernel/head.S b/arch/nios2/kernel/head.S new file mode 100644 index 0000000..372ce4a --- /dev/null +++ b/arch/nios2/kernel/head.S @@ -0,0 +1,175 @@ +/* + * Copyright (C) 2009 Wind River Systems Inc + * Implemented by fredrik.markstrom@xxxxxxxxx and ivarholmqvist@xxxxxxxxx + * Copyright (C) 2004 Microtronix Datacom Ltd + * Copyright (C) 2001 Vic Phillips, Microtronix Datacom Ltd. + * + * Based on head.S for Altera's Excalibur development board with nios processor + * + * Based on the following from the Excalibur sdk distribution: + * NA_MemoryMap.s, NR_JumpToStart.s, NR_Setup.s, NR_CWPManager.s + * + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file "COPYING" in the main directory of this archive + * for more details. + */ + +#include <linux/init.h> +#include <linux/linkage.h> +#include <asm/thread_info.h> +#include <asm/processor.h> +#include <asm/cache.h> +#include <asm/page.h> +#include <asm/asm-offsets.h> +#include <asm/asm-macros.h> + +/* + * ZERO_PAGE is a special page that is used for zero-initialized + * data and COW. + */ +.data +.global empty_zero_page +.align 12 +empty_zero_page: + .space PAGE_SIZE + +/* + * This global variable is used as an extension to the nios' + * STATUS register to emulate a user/supervisor mode. + */ + .data + .align 2 + .set noat + + .global _current_thread +_current_thread: + .long 0 +/* + * Input(s): passed from u-boot + * r4 - Optional pointer to a board information structure. + * r5 - Optional pointer to the physical starting address of the init RAM + * disk. + * r6 - Optional pointer to the physical ending address of the init RAM + * disk. + * r7 - Optional pointer to the physical starting address of any kernel + * command-line parameters. + */ + +/* + * First executable code - detected and jumped to by the ROM bootstrap + * if the code resides in flash (looks for "Nios" at offset 0x0c from + * the potential executable image). + */ + __HEAD +ENTRY(_start) + wrctl status, r0 /* Disable interrupts */ + + /* Initialize all cache lines within the instruction cache */ + movia r1, NIOS2_ICACHE_SIZE + movui r2, NIOS2_ICACHE_LINE_SIZE + +icache_init: + initi r1 + sub r1, r1, r2 + bgt r1, r0, icache_init + br 1f + + /* + * This is the default location for the exception handler. Code in jump + * to our handler + */ +ENTRY(exception_handler_hook) + movia r24, inthandler + jmp r24 + +ENTRY(fast_handler) + nextpc et +helper: + stw r3, r3save - helper(et) + + rdctl r3 , pteaddr + srli r3, r3, 12 + slli r3, r3, 2 + movia et, pgd_current + + ldw et, 0(et) + add r3, et, r3 + ldw et, 0(r3) + + rdctl r3, pteaddr + andi r3, r3, 0xfff + add et, r3, et + ldw et, 0(et) + wrctl tlbacc, et + nextpc et +helper2: + ldw r3, r3save - helper2(et) + subi ea, ea, 4 + eret +r3save: + .word 0x0 +ENTRY(fast_handler_end) + +1: + /* + * After the instruction cache is initialized, the data cache must + * also be initialized. + */ + movia r1, NIOS2_DCACHE_SIZE + movui r2, NIOS2_DCACHE_LINE_SIZE + +dcache_init: + initd 0(r1) + sub r1, r1, r2 + bgt r1, r0, dcache_init + + nextpc r1 /* Find out where we are */ +chkadr: + movia r2, chkadr + beq r1, r2,finish_move /* We are running in RAM done */ + addi r1, r1,(_start - chkadr) /* Source */ + movia r2, _start /* Destination */ + movia r3, __bss_start /* End of copy */ + +loop_move: /* r1: src, r2: dest, r3: last dest */ + ldw r8, 0(r1) /* load a word from [r1] */ + stw r8, 0(r2) /* store a word to dest [r2] */ + flushd 0(r2) /* Flush cache for safety */ + addi r1, r1, 4 /* inc the src addr */ + addi r2, r2, 4 /* inc the dest addr */ + blt r2, r3, loop_move + + movia r1, finish_move /* VMA(_start)->l1 */ + jmp r1 /* jmp to _start */ + +finish_move: + + /* Mask off all possible interrupts */ + wrctl ienable, r0 + + /* Clear .bss */ + movia r2, __bss_start + movia r1, __bss_stop +1: + stb r0, 0(r2) + addi r2, r2, 1 + bne r1, r2, 1b + + movia r1, init_thread_union /* set stack at top of the task union */ + addi sp, r1, THREAD_SIZE + movia r2, _current_thread /* Remember current thread */ + stw r1, 0(r2) + + movia r1, nios2_boot_init /* save args r4-r7 passed from u-boot */ + callr r1 + + movia r1, start_kernel /* call start_kernel as a subroutine */ + callr r1 + + /* If we return from start_kernel, break to the oci debugger and + * buggered we are. + */ + break + + /* End of startup code */ +.set at diff --git a/arch/nios2/kernel/setup.c b/arch/nios2/kernel/setup.c new file mode 100644 index 0000000..cb3121f --- /dev/null +++ b/arch/nios2/kernel/setup.c @@ -0,0 +1,218 @@ +/* + * Nios2-specific parts of system setup + * + * Copyright (C) 2010 Tobias Klauser <tklauser@xxxxxxxxxx> + * Copyright (C) 2004 Microtronix Datacom Ltd. + * Copyright (C) 2001 Vic Phillips <vic@xxxxxxxxxxxxxxx> + * + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file "COPYING" in the main directory of this archive + * for more details. + */ + +#include <linux/export.h> +#include <linux/kernel.h> +#include <linux/mm.h> +#include <linux/sched.h> +#include <linux/console.h> +#include <linux/bootmem.h> +#include <linux/initrd.h> +#include <linux/of_fdt.h> + +#include <asm/mmu_context.h> +#include <asm/sections.h> +#include <asm/setup.h> +#include <asm/cpuinfo.h> + +unsigned long memory_start; +EXPORT_SYMBOL(memory_start); + +unsigned long memory_end; +EXPORT_SYMBOL(memory_end); + +unsigned long memory_size; + +static struct pt_regs fake_regs = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, + 0}; + +/* Copy a short hook instruction sequence to the exception address */ +static inline void copy_exception_handler(unsigned int addr) +{ + unsigned int start = (unsigned int) exception_handler_hook; + volatile unsigned int tmp = 0; + + if (start == addr) { + /* The CPU exception address already points to the handler. */ + return; + } + + __asm__ __volatile__ ( + "ldw %2,0(%0)\n" + "stw %2,0(%1)\n" + "ldw %2,4(%0)\n" + "stw %2,4(%1)\n" + "ldw %2,8(%0)\n" + "stw %2,8(%1)\n" + "flushd 0(%1)\n" + "flushd 4(%1)\n" + "flushd 8(%1)\n" + "flushi %1\n" + "addi %1,%1,4\n" + "flushi %1\n" + "addi %1,%1,4\n" + "flushi %1\n" + "flushp\n" + : /* no output registers */ + : "r" (start), "r" (addr), "r" (tmp) + : "memory" + ); +} + +/* Copy the fast TLB miss handler */ +static inline void copy_fast_tlb_miss_handler(unsigned int addr) +{ + unsigned int start = (unsigned int) fast_handler; + unsigned int end = (unsigned int) fast_handler_end; + volatile unsigned int tmp = 0; + + __asm__ __volatile__ ( + "1:\n" + " ldw %3,0(%0)\n" + " stw %3,0(%1)\n" + " flushd 0(%1)\n" + " flushi %1\n" + " flushp\n" + " addi %0,%0,4\n" + " addi %1,%1,4\n" + " bne %0,%2,1b\n" + : /* no output registers */ + : "r" (start), "r" (addr), "r" (end), "r" (tmp) + : "memory" + ); +} + +/* + * save args passed from u-boot, called from head.S + * + * @r4: NIOS magic + * @r5: initrd start + * @r6: initrd end or fdt + * @r7: kernel command line + */ +asmlinkage void __init nios2_boot_init(unsigned r4, unsigned r5, unsigned r6, + unsigned r7) +{ + unsigned dtb_passed = 0; + char cmdline_passed[COMMAND_LINE_SIZE] = { 0, }; + +#if defined(CONFIG_NIOS2_PASS_CMDLINE) + if (r4 == 0x534f494e) { /* r4 is magic NIOS */ +#if defined(CONFIG_BLK_DEV_INITRD) + if (r5) { /* initramfs */ + initrd_start = r5; + initrd_end = r6; + } +#endif /* CONFIG_BLK_DEV_INITRD */ + dtb_passed = r6; + + if (r7) + strncpy(cmdline_passed, (char *)r7, COMMAND_LINE_SIZE); + } +#endif + + early_init_devtree((void *)dtb_passed); + +#ifndef CONFIG_CMDLINE_FORCE + if (cmdline_passed[0]) + strncpy(boot_command_line, cmdline_passed, COMMAND_LINE_SIZE); +#ifdef CONFIG_NIOS2_CMDLINE_IGNORE_DTB + else + strncpy(boot_command_line, CONFIG_CMDLINE, COMMAND_LINE_SIZE); +#endif +#endif +} + +void __init setup_arch(char **cmdline_p) +{ + int bootmap_size; + + console_verbose(); + + memory_start = PAGE_ALIGN((unsigned long)__pa(_end)); + memory_end = (unsigned long) CONFIG_NIOS2_MEM_BASE + memory_size; + + init_mm.start_code = (unsigned long) _stext; + init_mm.end_code = (unsigned long) _etext; + init_mm.end_data = (unsigned long) _edata; + init_mm.brk = (unsigned long) _end; + init_task.thread.kregs = &fake_regs; + + /* Keep a copy of command line */ + *cmdline_p = boot_command_line; + + min_low_pfn = PFN_UP(memory_start); + max_low_pfn = PFN_DOWN(memory_end); + max_mapnr = max_low_pfn; + + /* + * give all the memory to the bootmap allocator, tell it to put the + * boot mem_map at the start of memory + */ + pr_debug("init_bootmem_node(?,%#lx, %#x, %#lx)\n", + min_low_pfn, PFN_DOWN(PHYS_OFFSET), max_low_pfn); + bootmap_size = init_bootmem_node(NODE_DATA(0), + min_low_pfn, PFN_DOWN(PHYS_OFFSET), + max_low_pfn); + + /* + * free the usable memory, we have to make sure we do not free + * the bootmem bitmap so we then reserve it after freeing it :-) + */ + pr_debug("free_bootmem(%#lx, %#lx)\n", + memory_start, memory_end - memory_start); + free_bootmem(memory_start, memory_end - memory_start); + + /* + * Reserve the bootmem bitmap itself as well. We do this in two + * steps (first step was init_bootmem()) because this catches + * the (very unlikely) case of us accidentally initializing the + * bootmem allocator with an invalid RAM area. + * + * Arguments are start, size + */ + pr_debug("reserve_bootmem(%#lx, %#x)\n", memory_start, bootmap_size); + reserve_bootmem(memory_start, bootmap_size, BOOTMEM_DEFAULT); + +#ifdef CONFIG_BLK_DEV_INITRD + if (initrd_start) { + reserve_bootmem(virt_to_phys((void *)initrd_start), + initrd_end - initrd_start, BOOTMEM_DEFAULT); + } +#endif /* CONFIG_BLK_DEV_INITRD */ + + unflatten_and_copy_device_tree(); + + setup_cpuinfo(); + + copy_exception_handler(cpuinfo.exception_addr); + + mmu_init(); + + copy_fast_tlb_miss_handler(cpuinfo.fast_tlb_miss_exc_addr); + + /* + * Initialize MMU context handling here because data from cpuinfo is + * needed for this. + */ + mmu_context_init(); + + /* + * get kmalloc into gear + */ + paging_init(); + +#if defined(CONFIG_VT) && defined(CONFIG_DUMMY_CONSOLE) + conswitchp = &dummy_con; +#endif +} -- 1.7.7.4 -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
