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/bootmem.h>
  20 #include <linux/memblock.h>
  21 #include <linux/initrd.h>
  22 #include <linux/of_fdt.h>
  23 #include <linux/screen_info.h>
  24
  25 #include <asm/mmu_context.h>
  26 #include <asm/sections.h>
  27 #include <asm/setup.h>
  28 #include <asm/cpuinfo.h>
  29
  30 unsigned long memory_start;
  31 EXPORT_SYMBOL(memory_start);
  32
  33 unsigned long memory_end;
  34 EXPORT_SYMBOL(memory_end);
  35
  36 unsigned long memory_size;
  37
  38 static struct pt_regs fake_regs = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
  39                                         0, 0, 0, 0, 0, 0,
  40                                         0};
  41
  42 #ifdef CONFIG_VT
  43 struct screen_info screen_info;
  44 #endif
  45
  46 /* Copy a short hook instruction sequence to the exception address */
  47 static inline void copy_exception_handler(unsigned int addr)
  48 {
  49         unsigned int start = (unsigned int) exception_handler_hook;
  50         volatile unsigned int tmp = 0;
  51
  52         if (start == addr) {
  53                 /* The CPU exception address already points to the handler. */
  54                 return;
  55         }
  56
  57         __asm__ __volatile__ (
  58                 "ldw    %2,0(%0)\n"
  59                 "stw    %2,0(%1)\n"
  60                 "ldw    %2,4(%0)\n"
  61                 "stw    %2,4(%1)\n"
  62                 "ldw    %2,8(%0)\n"
  63                 "stw    %2,8(%1)\n"
  64                 "flushd 0(%1)\n"
  65                 "flushd 4(%1)\n"
  66                 "flushd 8(%1)\n"
  67                 "flushi %1\n"
  68                 "addi   %1,%1,4\n"
  69                 "flushi %1\n"
  70                 "addi   %1,%1,4\n"
  71                 "flushi %1\n"
  72                 "flushp\n"
  73                 : /* no output registers */
  74                 : "r" (start), "r" (addr), "r" (tmp)
  75                 : "memory"
  76         );
  77 }
  78
  79 /* Copy the fast TLB miss handler */
  80 static inline void copy_fast_tlb_miss_handler(unsigned int addr)
  81 {
  82         unsigned int start = (unsigned int) fast_handler;
  83         unsigned int end = (unsigned int) fast_handler_end;
  84         volatile unsigned int tmp = 0;
  85
  86         __asm__ __volatile__ (
  87                 "1:\n"
  88                 "       ldw     %3,0(%0)\n"
  89                 "       stw     %3,0(%1)\n"
  90                 "       flushd  0(%1)\n"
  91                 "       flushi  %1\n"
  92                 "       flushp\n"
  93                 "       addi    %0,%0,4\n"
  94                 "       addi    %1,%1,4\n"
  95                 "       bne     %0,%2,1b\n"
  96                 : /* no output registers */
  97                 : "r" (start), "r" (addr), "r" (end), "r" (tmp)
  98                 : "memory"
  99         );
 100 }
 101
 102 /*
 103  * save args passed from u-boot, called from head.S
 104  *
 105  * @r4: NIOS magic
 106  * @r5: initrd start
 107  * @r6: initrd end or fdt
 108  * @r7: kernel command line
 109  */
 110 asmlinkage void __init nios2_boot_init(unsigned r4, unsigned r5, unsigned r6,
 111                                        unsigned r7)
 112 {
 113         unsigned dtb_passed = 0;
 114         char cmdline_passed[COMMAND_LINE_SIZE] __maybe_unused = { 0, };
 115
 116 #if defined(CONFIG_NIOS2_PASS_CMDLINE)
 117         if (r4 == 0x534f494e) { /* r4 is magic NIOS */
 118 #if defined(CONFIG_BLK_DEV_INITRD)
 119                 if (r5) { /* initramfs */
 120                         initrd_start = r5;
 121                         initrd_end = r6;
 122                 }
 123 #endif /* CONFIG_BLK_DEV_INITRD */
 124                 dtb_passed = r6;
 125
 126                 if (r7)
 127                         strncpy(cmdline_passed, (char *)r7, COMMAND_LINE_SIZE);
 128         }
 129 #endif
 130
 131         early_init_devtree((void *)dtb_passed);
 132
 133 #ifndef CONFIG_CMDLINE_FORCE
 134         if (cmdline_passed[0])
 135                 strncpy(boot_command_line, cmdline_passed, COMMAND_LINE_SIZE);
 136 #ifdef CONFIG_NIOS2_CMDLINE_IGNORE_DTB
 137         else
 138                 strncpy(boot_command_line, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
 139 #endif
 140 #endif
 141
 142         parse_early_param();
 143 }
 144
 145 void __init setup_arch(char **cmdline_p)
 146 {
 147         int dram_start;
 148
 149         console_verbose();
 150
 151         dram_start = memblock_start_of_DRAM();
 152         memory_size = memblock_phys_mem_size();
 153         memory_start = PAGE_ALIGN((unsigned long)__pa(_end));
 154         memory_end = (unsigned long) CONFIG_NIOS2_MEM_BASE + memory_size;
 155
 156         init_mm.start_code = (unsigned long) _stext;
 157         init_mm.end_code = (unsigned long) _etext;
 158         init_mm.end_data = (unsigned long) _edata;
 159         init_mm.brk = (unsigned long) _end;
 160         init_task.thread.kregs = &fake_regs;
 161
 162         /* Keep a copy of command line */
 163         *cmdline_p = boot_command_line;
 164
 165         min_low_pfn = PFN_UP(memory_start);
 166         max_low_pfn = PFN_DOWN(memory_end);
 167         max_mapnr = max_low_pfn;
 168
 169         memblock_reserve(dram_start, memory_start - dram_start);
 170 #ifdef CONFIG_BLK_DEV_INITRD
 171         if (initrd_start) {
 172                 memblock_reserve(virt_to_phys((void *)initrd_start),
 173                                 initrd_end - initrd_start);
 174         }
 175 #endif /* CONFIG_BLK_DEV_INITRD */
 176
 177         early_init_fdt_reserve_self();
 178         early_init_fdt_scan_reserved_mem();
 179
 180         unflatten_and_copy_device_tree();
 181
 182         setup_cpuinfo();
 183
 184         copy_exception_handler(cpuinfo.exception_addr);
 185
 186         mmu_init();
 187
 188         copy_fast_tlb_miss_handler(cpuinfo.fast_tlb_miss_exc_addr);
 189
 190         /*
 191          * Initialize MMU context handling here because data from cpuinfo is
 192          * needed for this.
 193          */
 194         mmu_context_init();
 195
 196         /*
 197          * get kmalloc into gear
 198          */
 199         paging_init();
 200
 201 #if defined(CONFIG_VT) && defined(CONFIG_DUMMY_CONSOLE)
 202         conswitchp = &dummy_con;
 203 #endif
 204 }