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