1/*
  2 * Nios2-specific parts of system setup
  3 *
  4 * Copyright (C) 2010 Tobias Klauser <tklauser@distanz.ch>
  5 * Copyright (C) 2004 Microtronix Datacom Ltd.
  6 * Copyright (C) 2001 Vic Phillips <vic@microtronix.com>
  7 *
  8 * This file is subject to the terms and conditions of the GNU General Public
  9 * License. See the file "COPYING" in the main directory of this archive
 10 * for more details.
 11 */
 12
 13#include <linux/export.h>
 14#include <linux/kernel.h>
 15#include <linux/mm.h>
 16#include <linux/sched.h>
 17#include <linux/console.h>
 18#include <linux/bootmem.h>
 19#include <linux/initrd.h>
 20#include <linux/of_fdt.h>
 21
 22#include <asm/mmu_context.h>
 23#include <asm/sections.h>
 24#include <asm/setup.h>
 25#include <asm/cpuinfo.h>
 26
 27unsigned long memory_start;
 28EXPORT_SYMBOL(memory_start);
 29
 30unsigned long memory_end;
 31EXPORT_SYMBOL(memory_end);
 32
 33unsigned long memory_size;
 34
 35static struct pt_regs fake_regs = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
 36					0, 0, 0, 0, 0, 0,
 37					0};
 38
 39/* Copy a short hook instruction sequence to the exception address */
 40static inline void copy_exception_handler(unsigned int addr)
 41{
 42	unsigned int start = (unsigned int) exception_handler_hook;
 43	volatile unsigned int tmp = 0;
 44
 45	if (start == addr) {
 46		/* The CPU exception address already points to the handler. */
 47		return;
 48	}
 49
 50	__asm__ __volatile__ (
 51		"ldw	%2,0(%0)\n"
 52		"stw	%2,0(%1)\n"
 53		"ldw	%2,4(%0)\n"
 54		"stw	%2,4(%1)\n"
 55		"ldw	%2,8(%0)\n"
 56		"stw	%2,8(%1)\n"
 57		"flushd	0(%1)\n"
 58		"flushd	4(%1)\n"
 59		"flushd	8(%1)\n"
 60		"flushi %1\n"
 61		"addi	%1,%1,4\n"
 62		"flushi %1\n"
 63		"addi	%1,%1,4\n"
 64		"flushi %1\n"
 65		"flushp\n"
 66		: /* no output registers */
 67		: "r" (start), "r" (addr), "r" (tmp)
 68		: "memory"
 69	);
 70}
 71
 72/* Copy the fast TLB miss handler */
 73static inline void copy_fast_tlb_miss_handler(unsigned int addr)
 74{
 75	unsigned int start = (unsigned int) fast_handler;
 76	unsigned int end = (unsigned int) fast_handler_end;
 77	volatile unsigned int tmp = 0;
 78
 79	__asm__ __volatile__ (
 80		"1:\n"
 81		"	ldw	%3,0(%0)\n"
 82		"	stw	%3,0(%1)\n"
 83		"	flushd	0(%1)\n"
 84		"	flushi	%1\n"
 85		"	flushp\n"
 86		"	addi	%0,%0,4\n"
 87		"	addi	%1,%1,4\n"
 88		"	bne	%0,%2,1b\n"
 89		: /* no output registers */
 90		: "r" (start), "r" (addr), "r" (end), "r" (tmp)
 91		: "memory"
 92	);
 93}
 94
 95/*
 96 * save args passed from u-boot, called from head.S
 97 *
 98 * @r4: NIOS magic
 99 * @r5: initrd start
100 * @r6: initrd end or fdt
101 * @r7: kernel command line
102 */
103asmlinkage void __init nios2_boot_init(unsigned r4, unsigned r5, unsigned r6,
104				       unsigned r7)
105{
106	unsigned dtb_passed = 0;
107	char cmdline_passed[COMMAND_LINE_SIZE] __maybe_unused = { 0, };
108
109#if defined(CONFIG_NIOS2_PASS_CMDLINE)
110	if (r4 == 0x534f494e) { /* r4 is magic NIOS */
111#if defined(CONFIG_BLK_DEV_INITRD)
112		if (r5) { /* initramfs */
113			initrd_start = r5;
114			initrd_end = r6;
115		}
116#endif /* CONFIG_BLK_DEV_INITRD */
117		dtb_passed = r6;
118
119		if (r7)
120			strncpy(cmdline_passed, (char *)r7, COMMAND_LINE_SIZE);
121	}
122#endif
123
124	early_init_devtree((void *)dtb_passed);
125
126#ifndef CONFIG_CMDLINE_FORCE
127	if (cmdline_passed[0])
128		strncpy(boot_command_line, cmdline_passed, COMMAND_LINE_SIZE);
129#ifdef CONFIG_NIOS2_CMDLINE_IGNORE_DTB
130	else
131		strncpy(boot_command_line, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
132#endif
133#endif
134}
135
136void __init setup_arch(char **cmdline_p)
137{
138	int bootmap_size;
139
140	console_verbose();
141
142#ifdef CONFIG_EARLY_PRINTK
143	setup_early_printk();
144#endif
145
146	memory_start = PAGE_ALIGN((unsigned long)__pa(_end));
147	memory_end = (unsigned long) CONFIG_NIOS2_MEM_BASE + memory_size;
148
149	init_mm.start_code = (unsigned long) _stext;
150	init_mm.end_code = (unsigned long) _etext;
151	init_mm.end_data = (unsigned long) _edata;
152	init_mm.brk = (unsigned long) _end;
153	init_task.thread.kregs = &fake_regs;
154
155	/* Keep a copy of command line */
156	*cmdline_p = boot_command_line;
157
158	min_low_pfn = PFN_UP(memory_start);
159	max_low_pfn = PFN_DOWN(memory_end);
160	max_mapnr = max_low_pfn;
161
162	/*
163	 * give all the memory to the bootmap allocator,  tell it to put the
164	 * boot mem_map at the start of memory
165	 */
166	pr_debug("init_bootmem_node(?,%#lx, %#x, %#lx)\n",
167		min_low_pfn, PFN_DOWN(PHYS_OFFSET), max_low_pfn);
168	bootmap_size = init_bootmem_node(NODE_DATA(0),
169					min_low_pfn, PFN_DOWN(PHYS_OFFSET),
170					max_low_pfn);
171
172	/*
173	 * free the usable memory,  we have to make sure we do not free
174	 * the bootmem bitmap so we then reserve it after freeing it :-)
175	 */
176	pr_debug("free_bootmem(%#lx, %#lx)\n",
177		memory_start, memory_end - memory_start);
178	free_bootmem(memory_start, memory_end - memory_start);
179
180	/*
181	 * Reserve the bootmem bitmap itself as well. We do this in two
182	 * steps (first step was init_bootmem()) because this catches
183	 * the (very unlikely) case of us accidentally initializing the
184	 * bootmem allocator with an invalid RAM area.
185	 *
186	 * Arguments are start, size
187	 */
188	pr_debug("reserve_bootmem(%#lx, %#x)\n", memory_start, bootmap_size);
189	reserve_bootmem(memory_start, bootmap_size, BOOTMEM_DEFAULT);
190
191#ifdef CONFIG_BLK_DEV_INITRD
192	if (initrd_start) {
193		reserve_bootmem(virt_to_phys((void *)initrd_start),
194				initrd_end - initrd_start, BOOTMEM_DEFAULT);
195	}
196#endif /* CONFIG_BLK_DEV_INITRD */
197
198	unflatten_and_copy_device_tree();
199
200	setup_cpuinfo();
201
202	copy_exception_handler(cpuinfo.exception_addr);
203
204	mmu_init();
205
206	copy_fast_tlb_miss_handler(cpuinfo.fast_tlb_miss_exc_addr);
207
208	/*
209	 * Initialize MMU context handling here because data from cpuinfo is
210	 * needed for this.
211	 */
212	mmu_context_init();
213
214	/*
215	 * get kmalloc into gear
216	 */
217	paging_init();
218
219#if defined(CONFIG_VT) && defined(CONFIG_DUMMY_CONSOLE)
220	conswitchp = &dummy_con;
221#endif
222}