arch/nios2/kernel/setup.c

   1 /*
   2  * Nios2-specific parts of system setup
   3  *
   4  * Copyright (C) 2010 Tobias Klauser <[email protected]>
   5  * Copyright (C) 2004 Microtronix Datacom Ltd.
   6  * Copyright (C) 2001 Vic Phillips <[email protected]>
   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 unsigned long memory_size;
  36
  37 static struct pt_regs fake_regs = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
  38                                         0, 0, 0, 0, 0, 0,
  39                                         0};
  40
  41 #ifdef CONFIG_VT
  42 struct screen_info screen_info;
  43 #endif
  44
  45 /* Copy a short hook instruction sequence to the exception address */
  46 static inline void copy_exception_handler(unsigned int addr)
  47 {
  48         unsigned int start = (unsigned int) exception_handler_hook;
  49         volatile unsigned int tmp = 0;
  50
  51         if (start == addr) {
  52                 /* The CPU exception address already points to the handler. */
  53                 return;
  54         }
  55
  56         __asm__ __volatile__ (
  57                 "ldw    %2,0(%0)\n"
  58                 "stw    %2,0(%1)\n"
  59                 "ldw    %2,4(%0)\n"
  60                 "stw    %2,4(%1)\n"
  61                 "ldw    %2,8(%0)\n"
  62                 "stw    %2,8(%1)\n"
  63                 "flushd 0(%1)\n"
  64                 "flushd 4(%1)\n"
  65                 "flushd 8(%1)\n"
  66                 "flushi %1\n"
  67                 "addi   %1,%1,4\n"
  68                 "flushi %1\n"
  69                 "addi   %1,%1,4\n"
  70                 "flushi %1\n"
  71                 "flushp\n"
  72                 : /* no output registers */
  73                 : "r" (start), "r" (addr), "r" (tmp)
  74                 : "memory"
  75         );
  76 }
  77
  78 /* Copy the fast TLB miss handler */
  79 static inline void copy_fast_tlb_miss_handler(unsigned int addr)
  80 {
  81         unsigned int start = (unsigned int) fast_handler;
  82         unsigned int end = (unsigned int) fast_handler_end;
  83         volatile unsigned int tmp = 0;
  84
  85         __asm__ __volatile__ (
  86                 "1:\n"
  87                 "       ldw     %3,0(%0)\n"
  88                 "       stw     %3,0(%1)\n"
  89                 "       flushd  0(%1)\n"
  90                 "       flushi  %1\n"
  91                 "       flushp\n"
  92                 "       addi    %0,%0,4\n"
  93                 "       addi    %1,%1,4\n"
  94                 "       bne     %0,%2,1b\n"
  95                 : /* no output registers */
  96                 : "r" (start), "r" (addr), "r" (end), "r" (tmp)
  97                 : "memory"
  98         );
  99 }
 100
 101 /*
 102  * save args passed from u-boot, called from head.S
 103  *
 104  * @r4: NIOS magic
 105  * @r5: initrd start
 106  * @r6: initrd end or fdt
 107  * @r7: kernel command line
 108  */
 109 asmlinkage void __init nios2_boot_init(unsigned r4, unsigned r5, unsigned r6,
 110                                        unsigned r7)
 111 {
 112         unsigned dtb_passed = 0;
 113         char cmdline_passed[COMMAND_LINE_SIZE] __maybe_unused = { 0, };
 114
 115 #if defined(CONFIG_NIOS2_PASS_CMDLINE)
 116         if (r4 == 0x534f494e) { /* r4 is magic NIOS */
 117 #if defined(CONFIG_BLK_DEV_INITRD)
 118                 if (r5) { /* initramfs */
 119                         initrd_start = r5;
 120                         initrd_end = r6;
 121                 }
 122 #endif /* CONFIG_BLK_DEV_INITRD */
 123                 dtb_passed = r6;
 124
 125                 if (r7)
 126                         strlcpy(cmdline_passed, (char *)r7, COMMAND_LINE_SIZE);
 127         }
 128 #endif
 129
 130         early_init_devtree((void *)dtb_passed);
 131
 132 #ifndef CONFIG_CMDLINE_FORCE
 133         if (cmdline_passed[0])
 134                 strlcpy(boot_command_line, cmdline_passed, COMMAND_LINE_SIZE);
 135 #ifdef CONFIG_NIOS2_CMDLINE_IGNORE_DTB
 136         else
 137                 strlcpy(boot_command_line, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
 138 #endif
 139 #endif
 140
 141         parse_early_param();
 142 }
 143
 144 void __init setup_arch(char **cmdline_p)
 145 {
 146         int dram_start;
 147
 148         console_verbose();
 149
 150         dram_start = memblock_start_of_DRAM();
 151         memory_size = memblock_phys_mem_size();
 152         memory_start = PAGE_ALIGN((unsigned long)__pa(_end));
 153         memory_end = (unsigned long) CONFIG_NIOS2_MEM_BASE + memory_size;
 154
 155         init_mm.start_code = (unsigned long) _stext;
 156         init_mm.end_code = (unsigned long) _etext;
 157         init_mm.end_data = (unsigned long) _edata;
 158         init_mm.brk = (unsigned long) _end;
 159         init_task.thread.kregs = &fake_regs;
 160
 161         /* Keep a copy of command line */
 162         *cmdline_p = boot_command_line;
 163
 164         min_low_pfn = PFN_UP(memory_start);
 165         max_low_pfn = PFN_DOWN(memory_end);
 166         max_mapnr = max_low_pfn;
 167
 168         memblock_reserve(dram_start, memory_start - dram_start);
 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 }