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>

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
+}