arch/nios2/kernel/setup.c

   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 }