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/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                         strncpy(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                 strncpy(boot_command_line, cmdline_passed, COMMAND_LINE_SIZE);
 135 #ifdef CONFIG_NIOS2_CMDLINE_IGNORE_DTB
 136         else
 137                 strncpy(boot_command_line, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
 138 #endif
 139 #endif
 140 }
 141
 142 void __init setup_arch(char **cmdline_p)
 143 {
 144         int bootmap_size;
 145
 146         console_verbose();
 147
 148 #ifdef CONFIG_EARLY_PRINTK
 149         setup_early_printk();
 150 #endif
 151
 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         /*
 169          * give all the memory to the bootmap allocator,  tell it to put the
 170          * boot mem_map at the start of memory
 171          */
 172         pr_debug("init_bootmem_node(?,%#lx, %#x, %#lx)\n",
 173                 min_low_pfn, PFN_DOWN(PHYS_OFFSET), max_low_pfn);
 174         bootmap_size = init_bootmem_node(NODE_DATA(0),
 175                                         min_low_pfn, PFN_DOWN(PHYS_OFFSET),
 176                                         max_low_pfn);
 177
 178         /*
 179          * free the usable memory,  we have to make sure we do not free
 180          * the bootmem bitmap so we then reserve it after freeing it :-)
 181          */
 182         pr_debug("free_bootmem(%#lx, %#lx)\n",
 183                 memory_start, memory_end - memory_start);
 184         free_bootmem(memory_start, memory_end - memory_start);
 185
 186         /*
 187          * Reserve the bootmem bitmap itself as well. We do this in two
 188          * steps (first step was init_bootmem()) because this catches
 189          * the (very unlikely) case of us accidentally initializing the
 190          * bootmem allocator with an invalid RAM area.
 191          *
 192          * Arguments are start, size
 193          */
 194         pr_debug("reserve_bootmem(%#lx, %#x)\n", memory_start, bootmap_size);
 195         reserve_bootmem(memory_start, bootmap_size, BOOTMEM_DEFAULT);
 196
 197 #ifdef CONFIG_BLK_DEV_INITRD
 198         if (initrd_start) {
 199                 reserve_bootmem(virt_to_phys((void *)initrd_start),
 200                                 initrd_end - initrd_start, BOOTMEM_DEFAULT);
 201         }
 202 #endif /* CONFIG_BLK_DEV_INITRD */
 203
 204         unflatten_and_copy_device_tree();
 205
 206         setup_cpuinfo();
 207
 208         copy_exception_handler(cpuinfo.exception_addr);
 209
 210         mmu_init();
 211
 212         copy_fast_tlb_miss_handler(cpuinfo.fast_tlb_miss_exc_addr);
 213
 214         /*
 215          * Initialize MMU context handling here because data from cpuinfo is
 216          * needed for this.
 217          */
 218         mmu_context_init();
 219
 220         /*
 221          * get kmalloc into gear
 222          */
 223         paging_init();
 224
 225 #if defined(CONFIG_VT) && defined(CONFIG_DUMMY_CONSOLE)
 226         conswitchp = &dummy_con;
 227 #endif
 228 }