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 27 unsigned long memory_start; 28 EXPORT_SYMBOL(memory_start); 29 30 unsigned long memory_end; 31 EXPORT_SYMBOL(memory_end); 32 33 unsigned long memory_size; 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 /* Copy a short hook instruction sequence to the exception address */ 40 static 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 */ 73 static 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 */ 103 asmlinkage 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] = { 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 } 135 136 void __init setup_arch(char **cmdline_p) 137 { 138 int bootmap_size; 139 140 console_verbose(); 141 142 memory_start = PAGE_ALIGN((unsigned long)__pa(_end)); 143 memory_end = (unsigned long) CONFIG_NIOS2_MEM_BASE + memory_size; 144 145 init_mm.start_code = (unsigned long) _stext; 146 init_mm.end_code = (unsigned long) _etext; 147 init_mm.end_data = (unsigned long) _edata; 148 init_mm.brk = (unsigned long) _end; 149 init_task.thread.kregs = &fake_regs; 150 151 /* Keep a copy of command line */ 152 *cmdline_p = boot_command_line; 153 154 min_low_pfn = PFN_UP(memory_start); 155 max_low_pfn = PFN_DOWN(memory_end); 156 max_mapnr = max_low_pfn; 157 158 /* 159 * give all the memory to the bootmap allocator, tell it to put the 160 * boot mem_map at the start of memory 161 */ 162 pr_debug("init_bootmem_node(?,%#lx, %#x, %#lx)\n", 163 min_low_pfn, PFN_DOWN(PHYS_OFFSET), max_low_pfn); 164 bootmap_size = init_bootmem_node(NODE_DATA(0), 165 min_low_pfn, PFN_DOWN(PHYS_OFFSET), 166 max_low_pfn); 167 168 /* 169 * free the usable memory, we have to make sure we do not free 170 * the bootmem bitmap so we then reserve it after freeing it :-) 171 */ 172 pr_debug("free_bootmem(%#lx, %#lx)\n", 173 memory_start, memory_end - memory_start); 174 free_bootmem(memory_start, memory_end - memory_start); 175 176 /* 177 * Reserve the bootmem bitmap itself as well. We do this in two 178 * steps (first step was init_bootmem()) because this catches 179 * the (very unlikely) case of us accidentally initializing the 180 * bootmem allocator with an invalid RAM area. 181 * 182 * Arguments are start, size 183 */ 184 pr_debug("reserve_bootmem(%#lx, %#x)\n", memory_start, bootmap_size); 185 reserve_bootmem(memory_start, bootmap_size, BOOTMEM_DEFAULT); 186 187 #ifdef CONFIG_BLK_DEV_INITRD 188 if (initrd_start) { 189 reserve_bootmem(virt_to_phys((void *)initrd_start), 190 initrd_end - initrd_start, BOOTMEM_DEFAULT); 191 } 192 #endif /* CONFIG_BLK_DEV_INITRD */ 193 194 unflatten_and_copy_device_tree(); 195 196 setup_cpuinfo(); 197 198 copy_exception_handler(cpuinfo.exception_addr); 199 200 mmu_init(); 201 202 copy_fast_tlb_miss_handler(cpuinfo.fast_tlb_miss_exc_addr); 203 204 /* 205 * Initialize MMU context handling here because data from cpuinfo is 206 * needed for this. 207 */ 208 mmu_context_init(); 209 210 /* 211 * get kmalloc into gear 212 */ 213 paging_init(); 214 215 #if defined(CONFIG_VT) && defined(CONFIG_DUMMY_CONSOLE) 216 conswitchp = &dummy_con; 217 #endif 218 } 219