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/memblock.h> 21 #include <linux/initrd.h> 22 #include <linux/of_fdt.h> 23 #include <linux/screen_info.h> 24 25 #include <asm/mmu_context.h> 26 #include <asm/sections.h> 27 #include <asm/setup.h> 28 #include <asm/cpuinfo.h> 29 30 unsigned long memory_start; 31 EXPORT_SYMBOL(memory_start); 32 33 unsigned long memory_end; 34 EXPORT_SYMBOL(memory_end); 35 36 unsigned long memory_size; 37 38 static struct pt_regs fake_regs = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 39 0, 0, 0, 0, 0, 0, 40 0}; 41 42 #ifdef CONFIG_VT 43 struct screen_info screen_info; 44 #endif 45 46 /* Copy a short hook instruction sequence to the exception address */ 47 static inline void copy_exception_handler(unsigned int addr) 48 { 49 unsigned int start = (unsigned int) exception_handler_hook; 50 volatile unsigned int tmp = 0; 51 52 if (start == addr) { 53 /* The CPU exception address already points to the handler. */ 54 return; 55 } 56 57 __asm__ __volatile__ ( 58 "ldw %2,0(%0)\n" 59 "stw %2,0(%1)\n" 60 "ldw %2,4(%0)\n" 61 "stw %2,4(%1)\n" 62 "ldw %2,8(%0)\n" 63 "stw %2,8(%1)\n" 64 "flushd 0(%1)\n" 65 "flushd 4(%1)\n" 66 "flushd 8(%1)\n" 67 "flushi %1\n" 68 "addi %1,%1,4\n" 69 "flushi %1\n" 70 "addi %1,%1,4\n" 71 "flushi %1\n" 72 "flushp\n" 73 : /* no output registers */ 74 : "r" (start), "r" (addr), "r" (tmp) 75 : "memory" 76 ); 77 } 78 79 /* Copy the fast TLB miss handler */ 80 static inline void copy_fast_tlb_miss_handler(unsigned int addr) 81 { 82 unsigned int start = (unsigned int) fast_handler; 83 unsigned int end = (unsigned int) fast_handler_end; 84 volatile unsigned int tmp = 0; 85 86 __asm__ __volatile__ ( 87 "1:\n" 88 " ldw %3,0(%0)\n" 89 " stw %3,0(%1)\n" 90 " flushd 0(%1)\n" 91 " flushi %1\n" 92 " flushp\n" 93 " addi %0,%0,4\n" 94 " addi %1,%1,4\n" 95 " bne %0,%2,1b\n" 96 : /* no output registers */ 97 : "r" (start), "r" (addr), "r" (end), "r" (tmp) 98 : "memory" 99 ); 100 } 101 102 /* 103 * save args passed from u-boot, called from head.S 104 * 105 * @r4: NIOS magic 106 * @r5: initrd start 107 * @r6: initrd end or fdt 108 * @r7: kernel command line 109 */ 110 asmlinkage void __init nios2_boot_init(unsigned r4, unsigned r5, unsigned r6, 111 unsigned r7) 112 { 113 unsigned dtb_passed = 0; 114 char cmdline_passed[COMMAND_LINE_SIZE] __maybe_unused = { 0, }; 115 116 #if defined(CONFIG_NIOS2_PASS_CMDLINE) 117 if (r4 == 0x534f494e) { /* r4 is magic NIOS */ 118 #if defined(CONFIG_BLK_DEV_INITRD) 119 if (r5) { /* initramfs */ 120 initrd_start = r5; 121 initrd_end = r6; 122 } 123 #endif /* CONFIG_BLK_DEV_INITRD */ 124 dtb_passed = r6; 125 126 if (r7) 127 strncpy(cmdline_passed, (char *)r7, COMMAND_LINE_SIZE); 128 } 129 #endif 130 131 early_init_devtree((void *)dtb_passed); 132 133 #ifndef CONFIG_CMDLINE_FORCE 134 if (cmdline_passed[0]) 135 strncpy(boot_command_line, cmdline_passed, COMMAND_LINE_SIZE); 136 #ifdef CONFIG_NIOS2_CMDLINE_IGNORE_DTB 137 else 138 strncpy(boot_command_line, CONFIG_CMDLINE, COMMAND_LINE_SIZE); 139 #endif 140 #endif 141 142 parse_early_param(); 143 } 144 145 void __init setup_arch(char **cmdline_p) 146 { 147 int dram_start; 148 149 console_verbose(); 150 151 dram_start = memblock_start_of_DRAM(); 152 memory_size = memblock_phys_mem_size(); 153 memory_start = PAGE_ALIGN((unsigned long)__pa(_end)); 154 memory_end = (unsigned long) CONFIG_NIOS2_MEM_BASE + memory_size; 155 156 init_mm.start_code = (unsigned long) _stext; 157 init_mm.end_code = (unsigned long) _etext; 158 init_mm.end_data = (unsigned long) _edata; 159 init_mm.brk = (unsigned long) _end; 160 init_task.thread.kregs = &fake_regs; 161 162 /* Keep a copy of command line */ 163 *cmdline_p = boot_command_line; 164 165 min_low_pfn = PFN_UP(memory_start); 166 max_low_pfn = PFN_DOWN(memory_end); 167 max_mapnr = max_low_pfn; 168 169 memblock_reserve(dram_start, memory_start - dram_start); 170 #ifdef CONFIG_BLK_DEV_INITRD 171 if (initrd_start) { 172 memblock_reserve(virt_to_phys((void *)initrd_start), 173 initrd_end - initrd_start); 174 } 175 #endif /* CONFIG_BLK_DEV_INITRD */ 176 177 early_init_fdt_reserve_self(); 178 early_init_fdt_scan_reserved_mem(); 179 180 unflatten_and_copy_device_tree(); 181 182 setup_cpuinfo(); 183 184 copy_exception_handler(cpuinfo.exception_addr); 185 186 mmu_init(); 187 188 copy_fast_tlb_miss_handler(cpuinfo.fast_tlb_miss_exc_addr); 189 190 /* 191 * Initialize MMU context handling here because data from cpuinfo is 192 * needed for this. 193 */ 194 mmu_context_init(); 195 196 /* 197 * get kmalloc into gear 198 */ 199 paging_init(); 200 201 #if defined(CONFIG_VT) && defined(CONFIG_DUMMY_CONSOLE) 202 conswitchp = &dummy_con; 203 #endif 204 } 205