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authorLey Foon Tan <lftan@altera.com>2014-11-06 15:19:37 +0800
committerLey Foon Tan <lftan@altera.com>2014-12-08 12:55:49 +0800
commit27d22413e60009603bc4eb515392c2639ff31010 (patch)
tree9948df5e5259c938c358337daeed461dbaa32450 /arch/nios2/kernel
parentnios2: Assembly macros and definitions (diff)
downloadlinux-dev-27d22413e60009603bc4eb515392c2639ff31010.tar.xz
linux-dev-27d22413e60009603bc4eb515392c2639ff31010.zip
nios2: Kernel booting and initialization
This patch adds the kernel booting and the initial setup code. Signed-off-by: Ley Foon Tan <lftan@altera.com>
Diffstat (limited to 'arch/nios2/kernel')
-rw-r--r--arch/nios2/kernel/head.S175
-rw-r--r--arch/nios2/kernel/setup.c218
2 files changed, 393 insertions, 0 deletions
diff --git a/arch/nios2/kernel/head.S b/arch/nios2/kernel/head.S
new file mode 100644
index 000000000000..372ce4a33018
--- /dev/null
+++ b/arch/nios2/kernel/head.S
@@ -0,0 +1,175 @@
+/*
+ * Copyright (C) 2009 Wind River Systems Inc
+ * Implemented by fredrik.markstrom@gmail.com and ivarholmqvist@gmail.com
+ * 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 000000000000..cb3121f975d4
--- /dev/null
+++ b/arch/nios2/kernel/setup.c
@@ -0,0 +1,218 @@
+/*
+ * Nios2-specific parts of system setup
+ *
+ * Copyright (C) 2010 Tobias Klauser <tklauser@distanz.ch>
+ * Copyright (C) 2004 Microtronix Datacom Ltd.
+ * Copyright (C) 2001 Vic Phillips <vic@microtronix.com>
+ *
+ * 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
+}