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 23 #include <asm/mmu_context.h> 24 #include <asm/sections.h> 25 #include <asm/setup.h> 26 #include <asm/cpuinfo.h> 27 28 unsigned long memory_start; 29 EXPORT_SYMBOL(memory_start); 30 31 unsigned long memory_end; 32 EXPORT_SYMBOL(memory_end); 33 34 static struct pt_regs fake_regs = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 35 0, 0, 0, 0, 0, 0, 36 0}; 37 38 /* Copy a short hook instruction sequence to the exception address */ 39 static inline void copy_exception_handler(unsigned int addr) 40 { 41 unsigned int start = (unsigned int) exception_handler_hook; 42 volatile unsigned int tmp = 0; 43 44 if (start == addr) { 45 /* The CPU exception address already points to the handler. */ 46 return; 47 } 48 49 __asm__ __volatile__ ( 50 "ldw %2,0(%0)\n" 51 "stw %2,0(%1)\n" 52 "ldw %2,4(%0)\n" 53 "stw %2,4(%1)\n" 54 "ldw %2,8(%0)\n" 55 "stw %2,8(%1)\n" 56 "flushd 0(%1)\n" 57 "flushd 4(%1)\n" 58 "flushd 8(%1)\n" 59 "flushi %1\n" 60 "addi %1,%1,4\n" 61 "flushi %1\n" 62 "addi %1,%1,4\n" 63 "flushi %1\n" 64 "flushp\n" 65 : /* no output registers */ 66 : "r" (start), "r" (addr), "r" (tmp) 67 : "memory" 68 ); 69 } 70 71 /* Copy the fast TLB miss handler */ 72 static inline void copy_fast_tlb_miss_handler(unsigned int addr) 73 { 74 unsigned int start = (unsigned int) fast_handler; 75 unsigned int end = (unsigned int) fast_handler_end; 76 volatile unsigned int tmp = 0; 77 78 __asm__ __volatile__ ( 79 "1:\n" 80 " ldw %3,0(%0)\n" 81 " stw %3,0(%1)\n" 82 " flushd 0(%1)\n" 83 " flushi %1\n" 84 " flushp\n" 85 " addi %0,%0,4\n" 86 " addi %1,%1,4\n" 87 " bne %0,%2,1b\n" 88 : /* no output registers */ 89 : "r" (start), "r" (addr), "r" (end), "r" (tmp) 90 : "memory" 91 ); 92 } 93 94 /* 95 * save args passed from u-boot, called from head.S 96 * 97 * @r4: NIOS magic 98 * @r5: initrd start 99 * @r6: initrd end or fdt 100 * @r7: kernel command line 101 */ 102 asmlinkage void __init nios2_boot_init(unsigned r4, unsigned r5, unsigned r6, 103 unsigned r7) 104 { 105 unsigned dtb_passed = 0; 106 char cmdline_passed[COMMAND_LINE_SIZE] __maybe_unused = { 0, }; 107 108 #if defined(CONFIG_NIOS2_PASS_CMDLINE) 109 if (r4 == 0x534f494e) { /* r4 is magic NIOS */ 110 #if defined(CONFIG_BLK_DEV_INITRD) 111 if (r5) { /* initramfs */ 112 initrd_start = r5; 113 initrd_end = r6; 114 } 115 #endif /* CONFIG_BLK_DEV_INITRD */ 116 dtb_passed = r6; 117 118 if (r7) 119 strscpy(cmdline_passed, (char *)r7, COMMAND_LINE_SIZE); 120 } 121 #endif 122 123 early_init_devtree((void *)dtb_passed); 124 125 #ifndef CONFIG_CMDLINE_FORCE 126 if (cmdline_passed[0]) 127 strscpy(boot_command_line, cmdline_passed, COMMAND_LINE_SIZE); 128 #ifdef CONFIG_NIOS2_CMDLINE_IGNORE_DTB 129 else 130 strscpy(boot_command_line, CONFIG_CMDLINE, COMMAND_LINE_SIZE); 131 #endif 132 #endif 133 134 parse_early_param(); 135 } 136 137 static void __init find_limits(unsigned long *min, unsigned long *max_low, 138 unsigned long *max_high) 139 { 140 *max_low = PFN_DOWN(memblock_get_current_limit()); 141 *min = PFN_UP(memblock_start_of_DRAM()); 142 *max_high = PFN_DOWN(memblock_end_of_DRAM()); 143 } 144 145 void __init setup_arch(char **cmdline_p) 146 { 147 console_verbose(); 148 149 memory_start = memblock_start_of_DRAM(); 150 memory_end = memblock_end_of_DRAM(); 151 152 setup_initial_init_mm(_stext, _etext, _edata, _end); 153 init_task.thread.kregs = &fake_regs; 154 155 /* Keep a copy of command line */ 156 *cmdline_p = boot_command_line; 157 158 find_limits(&min_low_pfn, &max_low_pfn, &max_pfn); 159 max_mapnr = max_low_pfn; 160 161 memblock_reserve(__pa_symbol(_stext), _end - _stext); 162 #ifdef CONFIG_BLK_DEV_INITRD 163 if (initrd_start) { 164 memblock_reserve(virt_to_phys((void *)initrd_start), 165 initrd_end - initrd_start); 166 } 167 #endif /* CONFIG_BLK_DEV_INITRD */ 168 169 early_init_fdt_reserve_self(); 170 early_init_fdt_scan_reserved_mem(); 171 172 unflatten_and_copy_device_tree(); 173 174 setup_cpuinfo(); 175 176 copy_exception_handler(cpuinfo.exception_addr); 177 178 mmu_init(); 179 180 copy_fast_tlb_miss_handler(cpuinfo.fast_tlb_miss_exc_addr); 181 182 /* 183 * Initialize MMU context handling here because data from cpuinfo is 184 * needed for this. 185 */ 186 mmu_context_init(); 187 188 /* 189 * get kmalloc into gear 190 */ 191 paging_init(); 192 } 193