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