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/sched/task.h>
 18#include <linux/console.h>
 19#include <linux/bootmem.h>
 20#include <linux/initrd.h>
 21#include <linux/of_fdt.h>
 22#include <linux/screen_info.h>
 23
 24#include <asm/mmu_context.h>
 25#include <asm/sections.h>
 26#include <asm/setup.h>
 27#include <asm/cpuinfo.h>
 28
 29unsigned long memory_start;
 30EXPORT_SYMBOL(memory_start);
 31
 32unsigned long memory_end;
 33EXPORT_SYMBOL(memory_end);
 34
 35unsigned long memory_size;
 36
 37static struct pt_regs fake_regs = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
 38					0, 0, 0, 0, 0, 0,
 39					0};
 40
 41#ifdef CONFIG_VT
 42struct screen_info screen_info;
 43#endif
 44
 45/* Copy a short hook instruction sequence to the exception address */
 46static inline void copy_exception_handler(unsigned int addr)
 47{
 48	unsigned int start = (unsigned int) exception_handler_hook;
 49	volatile unsigned int tmp = 0;
 50
 51	if (start == addr) {
 52		/* The CPU exception address already points to the handler. */
 53		return;
 54	}
 55
 56	__asm__ __volatile__ (
 57		"ldw	%2,0(%0)\n"
 58		"stw	%2,0(%1)\n"
 59		"ldw	%2,4(%0)\n"
 60		"stw	%2,4(%1)\n"
 61		"ldw	%2,8(%0)\n"
 62		"stw	%2,8(%1)\n"
 63		"flushd	0(%1)\n"
 64		"flushd	4(%1)\n"
 65		"flushd	8(%1)\n"
 66		"flushi %1\n"
 67		"addi	%1,%1,4\n"
 68		"flushi %1\n"
 69		"addi	%1,%1,4\n"
 70		"flushi %1\n"
 71		"flushp\n"
 72		: /* no output registers */
 73		: "r" (start), "r" (addr), "r" (tmp)
 74		: "memory"
 75	);
 76}
 77
 78/* Copy the fast TLB miss handler */
 79static inline void copy_fast_tlb_miss_handler(unsigned int addr)
 80{
 81	unsigned int start = (unsigned int) fast_handler;
 82	unsigned int end = (unsigned int) fast_handler_end;
 83	volatile unsigned int tmp = 0;
 84
 85	__asm__ __volatile__ (
 86		"1:\n"
 87		"	ldw	%3,0(%0)\n"
 88		"	stw	%3,0(%1)\n"
 89		"	flushd	0(%1)\n"
 90		"	flushi	%1\n"
 91		"	flushp\n"
 92		"	addi	%0,%0,4\n"
 93		"	addi	%1,%1,4\n"
 94		"	bne	%0,%2,1b\n"
 95		: /* no output registers */
 96		: "r" (start), "r" (addr), "r" (end), "r" (tmp)
 97		: "memory"
 98	);
 99}
100
101/*
102 * save args passed from u-boot, called from head.S
103 *
104 * @r4: NIOS magic
105 * @r5: initrd start
106 * @r6: initrd end or fdt
107 * @r7: kernel command line
108 */
109asmlinkage void __init nios2_boot_init(unsigned r4, unsigned r5, unsigned r6,
110				       unsigned r7)
111{
112	unsigned dtb_passed = 0;
113	char cmdline_passed[COMMAND_LINE_SIZE] __maybe_unused = { 0, };
114
115#if defined(CONFIG_NIOS2_PASS_CMDLINE)
116	if (r4 == 0x534f494e) { /* r4 is magic NIOS */
117#if defined(CONFIG_BLK_DEV_INITRD)
118		if (r5) { /* initramfs */
119			initrd_start = r5;
120			initrd_end = r6;
121		}
122#endif /* CONFIG_BLK_DEV_INITRD */
123		dtb_passed = r6;
124
125		if (r7)
126			strncpy(cmdline_passed, (char *)r7, COMMAND_LINE_SIZE);
127	}
128#endif
129
130	early_init_devtree((void *)dtb_passed);
131
132#ifndef CONFIG_CMDLINE_FORCE
133	if (cmdline_passed[0])
134		strncpy(boot_command_line, cmdline_passed, COMMAND_LINE_SIZE);
135#ifdef CONFIG_NIOS2_CMDLINE_IGNORE_DTB
136	else
137		strncpy(boot_command_line, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
138#endif
139#endif
140
141	parse_early_param();
142}
143
144void __init setup_arch(char **cmdline_p)
145{
146	int bootmap_size;
147
148	console_verbose();
149
150	memory_start = PAGE_ALIGN((unsigned long)__pa(_end));
151	memory_end = (unsigned long) CONFIG_NIOS2_MEM_BASE + memory_size;
152
153	init_mm.start_code = (unsigned long) _stext;
154	init_mm.end_code = (unsigned long) _etext;
155	init_mm.end_data = (unsigned long) _edata;
156	init_mm.brk = (unsigned long) _end;
157	init_task.thread.kregs = &fake_regs;
158
159	/* Keep a copy of command line */
160	*cmdline_p = boot_command_line;
161
162	min_low_pfn = PFN_UP(memory_start);
163	max_low_pfn = PFN_DOWN(memory_end);
164	max_mapnr = max_low_pfn;
165
166	/*
167	 * give all the memory to the bootmap allocator,  tell it to put the
168	 * boot mem_map at the start of memory
169	 */
170	pr_debug("init_bootmem_node(?,%#lx, %#x, %#lx)\n",
171		min_low_pfn, PFN_DOWN(PHYS_OFFSET), max_low_pfn);
172	bootmap_size = init_bootmem_node(NODE_DATA(0),
173					min_low_pfn, PFN_DOWN(PHYS_OFFSET),
174					max_low_pfn);
175
176	/*
177	 * free the usable memory,  we have to make sure we do not free
178	 * the bootmem bitmap so we then reserve it after freeing it :-)
179	 */
180	pr_debug("free_bootmem(%#lx, %#lx)\n",
181		memory_start, memory_end - memory_start);
182	free_bootmem(memory_start, memory_end - memory_start);
183
184	/*
185	 * Reserve the bootmem bitmap itself as well. We do this in two
186	 * steps (first step was init_bootmem()) because this catches
187	 * the (very unlikely) case of us accidentally initializing the
188	 * bootmem allocator with an invalid RAM area.
189	 *
190	 * Arguments are start, size
191	 */
192	pr_debug("reserve_bootmem(%#lx, %#x)\n", memory_start, bootmap_size);
193	reserve_bootmem(memory_start, bootmap_size, BOOTMEM_DEFAULT);
194
195#ifdef CONFIG_BLK_DEV_INITRD
196	if (initrd_start) {
197		reserve_bootmem(virt_to_phys((void *)initrd_start),
198				initrd_end - initrd_start, BOOTMEM_DEFAULT);
199	}
200#endif /* CONFIG_BLK_DEV_INITRD */
201
202	early_init_fdt_reserve_self();
203	early_init_fdt_scan_reserved_mem();
204
205	unflatten_and_copy_device_tree();
206
207	setup_cpuinfo();
208
209	copy_exception_handler(cpuinfo.exception_addr);
210
211	mmu_init();
212
213	copy_fast_tlb_miss_handler(cpuinfo.fast_tlb_miss_exc_addr);
214
215	/*
216	 * Initialize MMU context handling here because data from cpuinfo is
217	 * needed for this.
218	 */
219	mmu_context_init();
220
221	/*
222	 * get kmalloc into gear
223	 */
224	paging_init();
225
226#if defined(CONFIG_VT) && defined(CONFIG_DUMMY_CONSOLE)
227	conswitchp = &dummy_con;
228#endif
229}