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/memblock.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 29 unsigned long memory_start; 30 EXPORT_SYMBOL(memory_start); 31 32 unsigned long memory_end; 33 EXPORT_SYMBOL(memory_end); 34 35 static 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 #ifdef CONFIG_VT 40 struct screen_info screen_info; 41 #endif 42 43 /* Copy a short hook instruction sequence to the exception address */ 44 static inline void copy_exception_handler(unsigned int addr) 45 { 46 unsigned int start = (unsigned int) exception_handler_hook; 47 volatile unsigned int tmp = 0; 48 49 if (start == addr) { 50 /* The CPU exception address already points to the handler. */ 51 return; 52 } 53 54 __asm__ __volatile__ ( 55 "ldw %2,0(%0)\n" 56 "stw %2,0(%1)\n" 57 "ldw %2,4(%0)\n" 58 "stw %2,4(%1)\n" 59 "ldw %2,8(%0)\n" 60 "stw %2,8(%1)\n" 61 "flushd 0(%1)\n" 62 "flushd 4(%1)\n" 63 "flushd 8(%1)\n" 64 "flushi %1\n" 65 "addi %1,%1,4\n" 66 "flushi %1\n" 67 "addi %1,%1,4\n" 68 "flushi %1\n" 69 "flushp\n" 70 : /* no output registers */ 71 : "r" (start), "r" (addr), "r" (tmp) 72 : "memory" 73 ); 74 } 75 76 /* Copy the fast TLB miss handler */ 77 static inline void copy_fast_tlb_miss_handler(unsigned int addr) 78 { 79 unsigned int start = (unsigned int) fast_handler; 80 unsigned int end = (unsigned int) fast_handler_end; 81 volatile unsigned int tmp = 0; 82 83 __asm__ __volatile__ ( 84 "1:\n" 85 " ldw %3,0(%0)\n" 86 " stw %3,0(%1)\n" 87 " flushd 0(%1)\n" 88 " flushi %1\n" 89 " flushp\n" 90 " addi %0,%0,4\n" 91 " addi %1,%1,4\n" 92 " bne %0,%2,1b\n" 93 : /* no output registers */ 94 : "r" (start), "r" (addr), "r" (end), "r" (tmp) 95 : "memory" 96 ); 97 } 98 99 /* 100 * save args passed from u-boot, called from head.S 101 * 102 * @r4: NIOS magic 103 * @r5: initrd start 104 * @r6: initrd end or fdt 105 * @r7: kernel command line 106 */ 107 asmlinkage void __init nios2_boot_init(unsigned r4, unsigned r5, unsigned r6, 108 unsigned r7) 109 { 110 unsigned dtb_passed = 0; 111 char cmdline_passed[COMMAND_LINE_SIZE] __maybe_unused = { 0, }; 112 113 #if defined(CONFIG_NIOS2_PASS_CMDLINE) 114 if (r4 == 0x534f494e) { /* r4 is magic NIOS */ 115 #if defined(CONFIG_BLK_DEV_INITRD) 116 if (r5) { /* initramfs */ 117 initrd_start = r5; 118 initrd_end = r6; 119 } 120 #endif /* CONFIG_BLK_DEV_INITRD */ 121 dtb_passed = r6; 122 123 if (r7) 124 strscpy(cmdline_passed, (char *)r7, COMMAND_LINE_SIZE); 125 } 126 #endif 127 128 early_init_devtree((void *)dtb_passed); 129 130 #ifndef CONFIG_CMDLINE_FORCE 131 if (cmdline_passed[0]) 132 strscpy(boot_command_line, cmdline_passed, COMMAND_LINE_SIZE); 133 #ifdef CONFIG_NIOS2_CMDLINE_IGNORE_DTB 134 else 135 strscpy(boot_command_line, CONFIG_CMDLINE, COMMAND_LINE_SIZE); 136 #endif 137 #endif 138 139 parse_early_param(); 140 } 141 142 static void __init find_limits(unsigned long *min, unsigned long *max_low, 143 unsigned long *max_high) 144 { 145 *max_low = PFN_DOWN(memblock_get_current_limit()); 146 *min = PFN_UP(memblock_start_of_DRAM()); 147 *max_high = PFN_DOWN(memblock_end_of_DRAM()); 148 } 149 150 void __init setup_arch(char **cmdline_p) 151 { 152 console_verbose(); 153 154 memory_start = memblock_start_of_DRAM(); 155 memory_end = memblock_end_of_DRAM(); 156 157 setup_initial_init_mm(_stext, _etext, _edata, _end); 158 init_task.thread.kregs = &fake_regs; 159 160 /* Keep a copy of command line */ 161 *cmdline_p = boot_command_line; 162 163 find_limits(&min_low_pfn, &max_low_pfn, &max_pfn); 164 max_mapnr = max_low_pfn; 165 166 memblock_reserve(__pa_symbol(_stext), _end - _stext); 167 #ifdef CONFIG_BLK_DEV_INITRD 168 if (initrd_start) { 169 memblock_reserve(virt_to_phys((void *)initrd_start), 170 initrd_end - initrd_start); 171 } 172 #endif /* CONFIG_BLK_DEV_INITRD */ 173 174 early_init_fdt_reserve_self(); 175 early_init_fdt_scan_reserved_mem(); 176 177 unflatten_and_copy_device_tree(); 178 179 setup_cpuinfo(); 180 181 copy_exception_handler(cpuinfo.exception_addr); 182 183 mmu_init(); 184 185 copy_fast_tlb_miss_handler(cpuinfo.fast_tlb_miss_exc_addr); 186 187 /* 188 * Initialize MMU context handling here because data from cpuinfo is 189 * needed for this. 190 */ 191 mmu_context_init(); 192 193 /* 194 * get kmalloc into gear 195 */ 196 paging_init(); 197 } 198