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 #include <linux/screen_info.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 unsigned long memory_size;
  35
  36 static struct pt_regs fake_regs = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
  37                                         0, 0, 0, 0, 0, 0,
  38                                         0};
  39
  40 #ifdef CONFIG_VT
  41 struct screen_info screen_info;
  42 #endif
  43
  44 /* Copy a short hook instruction sequence to the exception address */
  45 static inline void copy_exception_handler(unsigned int addr)
  46 {
  47         unsigned int start = (unsigned int) exception_handler_hook;
  48         volatile unsigned int tmp = 0;
  49
  50         if (start == addr) {
  51                 /* The CPU exception address already points to the handler. */
  52                 return;
  53         }
  54
  55         __asm__ __volatile__ (
  56                 "ldw    %2,0(%0)\n"
  57                 "stw    %2,0(%1)\n"
  58                 "ldw    %2,4(%0)\n"
  59                 "stw    %2,4(%1)\n"
  60                 "ldw    %2,8(%0)\n"
  61                 "stw    %2,8(%1)\n"
  62                 "flushd 0(%1)\n"
  63                 "flushd 4(%1)\n"
  64                 "flushd 8(%1)\n"
  65                 "flushi %1\n"
  66                 "addi   %1,%1,4\n"
  67                 "flushi %1\n"
  68                 "addi   %1,%1,4\n"
  69                 "flushi %1\n"
  70                 "flushp\n"
  71                 : /* no output registers */
  72                 : "r" (start), "r" (addr), "r" (tmp)
  73                 : "memory"
  74         );
  75 }
  76
  77 /* Copy the fast TLB miss handler */
  78 static inline void copy_fast_tlb_miss_handler(unsigned int addr)
  79 {
  80         unsigned int start = (unsigned int) fast_handler;
  81         unsigned int end = (unsigned int) fast_handler_end;
  82         volatile unsigned int tmp = 0;
  83
  84         __asm__ __volatile__ (
  85                 "1:\n"
  86                 "       ldw     %3,0(%0)\n"
  87                 "       stw     %3,0(%1)\n"
  88                 "       flushd  0(%1)\n"
  89                 "       flushi  %1\n"
  90                 "       flushp\n"
  91                 "       addi    %0,%0,4\n"
  92                 "       addi    %1,%1,4\n"
  93                 "       bne     %0,%2,1b\n"
  94                 : /* no output registers */
  95                 : "r" (start), "r" (addr), "r" (end), "r" (tmp)
  96                 : "memory"
  97         );
  98 }
  99
 100 /*
 101  * save args passed from u-boot, called from head.S
 102  *
 103  * @r4: NIOS magic
 104  * @r5: initrd start
 105  * @r6: initrd end or fdt
 106  * @r7: kernel command line
 107  */
 108 asmlinkage void __init nios2_boot_init(unsigned r4, unsigned r5, unsigned r6,
 109                                        unsigned r7)
 110 {
 111         unsigned dtb_passed = 0;
 112         char cmdline_passed[COMMAND_LINE_SIZE] __maybe_unused = { 0, };
 113
 114 #if defined(CONFIG_NIOS2_PASS_CMDLINE)
 115         if (r4 == 0x534f494e) { /* r4 is magic NIOS */
 116 #if defined(CONFIG_BLK_DEV_INITRD)
 117                 if (r5) { /* initramfs */
 118                         initrd_start = r5;
 119                         initrd_end = r6;
 120                 }
 121 #endif /* CONFIG_BLK_DEV_INITRD */
 122                 dtb_passed = r6;
 123
 124                 if (r7)
 125                         strncpy(cmdline_passed, (char *)r7, COMMAND_LINE_SIZE);
 126         }
 127 #endif
 128
 129         early_init_devtree((void *)dtb_passed);
 130
 131 #ifndef CONFIG_CMDLINE_FORCE
 132         if (cmdline_passed[0])
 133                 strncpy(boot_command_line, cmdline_passed, COMMAND_LINE_SIZE);
 134 #ifdef CONFIG_NIOS2_CMDLINE_IGNORE_DTB
 135         else
 136                 strncpy(boot_command_line, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
 137 #endif
 138 #endif
 139 }
 140
 141 void __init setup_arch(char **cmdline_p)
 142 {
 143         int bootmap_size;
 144
 145         console_verbose();
 146
 147 #ifdef CONFIG_EARLY_PRINTK
 148         setup_early_printk();
 149 #endif
 150
 151         memory_start = PAGE_ALIGN((unsigned long)__pa(_end));
 152         memory_end = (unsigned long) CONFIG_NIOS2_MEM_BASE + memory_size;
 153
 154         init_mm.start_code = (unsigned long) _stext;
 155         init_mm.end_code = (unsigned long) _etext;
 156         init_mm.end_data = (unsigned long) _edata;
 157         init_mm.brk = (unsigned long) _end;
 158         init_task.thread.kregs = &fake_regs;
 159
 160         /* Keep a copy of command line */
 161         *cmdline_p = boot_command_line;
 162
 163         min_low_pfn = PFN_UP(memory_start);
 164         max_low_pfn = PFN_DOWN(memory_end);
 165         max_mapnr = max_low_pfn;
 166
 167         /*
 168          * give all the memory to the bootmap allocator,  tell it to put the
 169          * boot mem_map at the start of memory
 170          */
 171         pr_debug("init_bootmem_node(?,%#lx, %#x, %#lx)\n",
 172                 min_low_pfn, PFN_DOWN(PHYS_OFFSET), max_low_pfn);
 173         bootmap_size = init_bootmem_node(NODE_DATA(0),
 174                                         min_low_pfn, PFN_DOWN(PHYS_OFFSET),
 175                                         max_low_pfn);
 176
 177         /*
 178          * free the usable memory,  we have to make sure we do not free
 179          * the bootmem bitmap so we then reserve it after freeing it :-)
 180          */
 181         pr_debug("free_bootmem(%#lx, %#lx)\n",
 182                 memory_start, memory_end - memory_start);
 183         free_bootmem(memory_start, memory_end - memory_start);
 184
 185         /*
 186          * Reserve the bootmem bitmap itself as well. We do this in two
 187          * steps (first step was init_bootmem()) because this catches
 188          * the (very unlikely) case of us accidentally initializing the
 189          * bootmem allocator with an invalid RAM area.
 190          *
 191          * Arguments are start, size
 192          */
 193         pr_debug("reserve_bootmem(%#lx, %#x)\n", memory_start, bootmap_size);
 194         reserve_bootmem(memory_start, bootmap_size, BOOTMEM_DEFAULT);
 195
 196 #ifdef CONFIG_BLK_DEV_INITRD
 197         if (initrd_start) {
 198                 reserve_bootmem(virt_to_phys((void *)initrd_start),
 199                                 initrd_end - initrd_start, BOOTMEM_DEFAULT);
 200         }
 201 #endif /* CONFIG_BLK_DEV_INITRD */
 202
 203         unflatten_and_copy_device_tree();
 204
 205         setup_cpuinfo();
 206
 207         copy_exception_handler(cpuinfo.exception_addr);
 208
 209         mmu_init();
 210
 211         copy_fast_tlb_miss_handler(cpuinfo.fast_tlb_miss_exc_addr);
 212
 213         /*
 214          * Initialize MMU context handling here because data from cpuinfo is
 215          * needed for this.
 216          */
 217         mmu_context_init();
 218
 219         /*
 220          * get kmalloc into gear
 221          */
 222         paging_init();
 223
 224 #if defined(CONFIG_VT) && defined(CONFIG_DUMMY_CONSOLE)
 225         conswitchp = &dummy_con;
 226 #endif
 227 }