arch/csky/kernel/setup.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 // Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
   3
   4 #include <linux/console.h>
   5 #include <linux/memblock.h>
   6 #include <linux/initrd.h>
   7 #include <linux/of.h>
   8 #include <linux/of_fdt.h>
   9 #include <linux/start_kernel.h>
  10 #include <linux/dma-map-ops.h>
  11 #include <linux/screen_info.h>
  12 #include <asm/sections.h>
  13 #include <asm/mmu_context.h>
  14 #include <asm/pgalloc.h>
  15
  16 #ifdef CONFIG_DUMMY_CONSOLE
  17 struct screen_info screen_info = {
  18         .orig_video_lines       = 30,
  19         .orig_video_cols        = 80,
  20         .orig_video_mode        = 0,
  21         .orig_video_ega_bx      = 0,
  22         .orig_video_isVGA       = 1,
  23         .orig_video_points      = 8
  24 };
  25 #endif
  26
  27 static void __init csky_memblock_init(void)
  28 {
  29         unsigned long lowmem_size = PFN_DOWN(LOWMEM_LIMIT - PHYS_OFFSET_OFFSET);
  30         unsigned long sseg_size = PFN_DOWN(SSEG_SIZE - PHYS_OFFSET_OFFSET);
  31         unsigned long max_zone_pfn[MAX_NR_ZONES] = { 0 };
  32         signed long size;
  33
  34         memblock_reserve(__pa(_start), _end - _start);
  35
  36         early_init_fdt_reserve_self();
  37         early_init_fdt_scan_reserved_mem();
  38
  39         memblock_dump_all();
  40
  41         min_low_pfn = PFN_UP(memblock_start_of_DRAM());
  42         max_low_pfn = max_pfn = PFN_DOWN(memblock_end_of_DRAM());
  43
  44         size = max_pfn - min_low_pfn;
  45
  46         if (size >= lowmem_size) {
  47                 max_low_pfn = min_low_pfn + lowmem_size;
  48 #ifdef CONFIG_PAGE_OFFSET_80000000
  49                 write_mmu_msa1(read_mmu_msa0() + SSEG_SIZE);
  50 #endif
  51         } else if (size > sseg_size) {
  52                 max_low_pfn = min_low_pfn + sseg_size;
  53         }
  54
  55         max_zone_pfn[ZONE_NORMAL] = max_low_pfn;
  56
  57         mmu_init(min_low_pfn, max_low_pfn);
  58
  59 #ifdef CONFIG_HIGHMEM
  60         max_zone_pfn[ZONE_HIGHMEM] = max_pfn;
  61
  62         highstart_pfn = max_low_pfn;
  63         highend_pfn   = max_pfn;
  64 #endif
  65         memblock_set_current_limit(PFN_PHYS(max_low_pfn));
  66
  67         dma_contiguous_reserve(0);
  68
  69         free_area_init(max_zone_pfn);
  70 }
  71
  72 void __init setup_arch(char **cmdline_p)
  73 {
  74         *cmdline_p = boot_command_line;
  75
  76         console_verbose();
  77
  78         pr_info("Phys. mem: %ldMB\n",
  79                 (unsigned long) memblock_phys_mem_size()/1024/1024);
  80
  81         setup_initial_init_mm(_start, _etext, _edata, _end);
  82
  83         parse_early_param();
  84
  85         csky_memblock_init();
  86
  87         unflatten_and_copy_device_tree();
  88
  89 #ifdef CONFIG_SMP
  90         setup_smp();
  91 #endif
  92
  93         sparse_init();
  94
  95         fixaddr_init();
  96
  97 #ifdef CONFIG_HIGHMEM
  98         kmap_init();
  99 #endif
 100 }
 101
 102 unsigned long va_pa_offset;
 103 EXPORT_SYMBOL(va_pa_offset);
 104
 105 static inline unsigned long read_mmu_msa(void)
 106 {
 107 #ifdef CONFIG_PAGE_OFFSET_80000000
 108         return read_mmu_msa0();
 109 #endif
 110
 111 #ifdef CONFIG_PAGE_OFFSET_A0000000
 112         return read_mmu_msa1();
 113 #endif
 114 }
 115
 116 asmlinkage __visible void __init csky_start(unsigned int unused,
 117                                             void *dtb_start)
 118 {
 119         /* Clean up bss section */
 120         memset(__bss_start, 0, __bss_stop - __bss_start);
 121
 122         va_pa_offset = read_mmu_msa() & ~(SSEG_SIZE - 1);
 123
 124         pre_trap_init();
 125
 126         if (dtb_start == NULL)
 127                 early_init_dt_scan(__dtb_start);
 128         else
 129                 early_init_dt_scan(dtb_start);
 130
 131         start_kernel();
 132
 133         asm volatile("br .\n");
 134 }