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authorLey Foon Tan <lftan@altera.com>2014-11-06 10:19:37 +0300
committerLey Foon Tan <lftan@altera.com>2014-12-08 07:55:49 +0300
commit27d22413e60009603bc4eb515392c2639ff31010 (patch)
tree9948df5e5259c938c358337daeed461dbaa32450 /arch/nios2/kernel/setup.c
parent39b505cb7929d272020a2c9c25f6e3cd7c112447 (diff)
downloadlinux-27d22413e60009603bc4eb515392c2639ff31010.tar.xz
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/setup.c')
-rw-r--r--arch/nios2/kernel/setup.c218
1 files changed, 218 insertions, 0 deletions
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
+}