csky/kernel/setup.c

0001 // SPDX-License-Identifier: GPL-2.0
0002 // Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
0003
0004 #include <linux/console.h>
0005 #include <linux/memblock.h>
0006 #include <linux/initrd.h>
0007 #include <linux/of.h>
0008 #include <linux/of_fdt.h>
0009 #include <linux/start_kernel.h>
0010 #include <linux/dma-map-ops.h>
0011 #include <linux/screen_info.h>
0012 #include <asm/sections.h>
0013 #include <asm/mmu_context.h>
0014 #include <asm/pgalloc.h>
0015
0016 #ifdef CONFIG_DUMMY_CONSOLE
0017 struct screen_info screen_info = {
0018     .orig_video_lines   = 30,
0019     .orig_video_cols    = 80,
0020     .orig_video_mode    = 0,
0021     .orig_video_ega_bx  = 0,
0022     .orig_video_isVGA   = 1,
0023     .orig_video_points  = 8
0024 };
0025 #endif
0026
0027 static void __init csky_memblock_init(void)
0028 {
0029     unsigned long lowmem_size = PFN_DOWN(LOWMEM_LIMIT - PHYS_OFFSET_OFFSET);
0030     unsigned long sseg_size = PFN_DOWN(SSEG_SIZE - PHYS_OFFSET_OFFSET);
0031     unsigned long max_zone_pfn[MAX_NR_ZONES] = { 0 };
0032     signed long size;
0033
0034     memblock_reserve(__pa(_start), _end - _start);
0035
0036     early_init_fdt_reserve_self();
0037     early_init_fdt_scan_reserved_mem();
0038
0039     memblock_dump_all();
0040
0041     min_low_pfn = PFN_UP(memblock_start_of_DRAM());
0042     max_low_pfn = max_pfn = PFN_DOWN(memblock_end_of_DRAM());
0043
0044     size = max_pfn - min_low_pfn;
0045
0046     if (size >= lowmem_size) {
0047         max_low_pfn = min_low_pfn + lowmem_size;
0048 #ifdef CONFIG_PAGE_OFFSET_80000000
0049         write_mmu_msa1(read_mmu_msa0() + SSEG_SIZE);
0050 #endif
0051     } else if (size > sseg_size) {
0052         max_low_pfn = min_low_pfn + sseg_size;
0053     }
0054
0055     max_zone_pfn[ZONE_NORMAL] = max_low_pfn;
0056
0057     mmu_init(min_low_pfn, max_low_pfn);
0058
0059 #ifdef CONFIG_HIGHMEM
0060     max_zone_pfn[ZONE_HIGHMEM] = max_pfn;
0061
0062     highstart_pfn = max_low_pfn;
0063     highend_pfn   = max_pfn;
0064 #endif
0065     memblock_set_current_limit(PFN_PHYS(max_low_pfn));
0066
0067     dma_contiguous_reserve(0);
0068
0069     free_area_init(max_zone_pfn);
0070 }
0071
0072 void __init setup_arch(char **cmdline_p)
0073 {
0074     *cmdline_p = boot_command_line;
0075
0076     console_verbose();
0077
0078     pr_info("Phys. mem: %ldMB\n",
0079         (unsigned long) memblock_phys_mem_size()/1024/1024);
0080
0081     setup_initial_init_mm(_start, _etext, _edata, _end);
0082
0083     parse_early_param();
0084
0085     csky_memblock_init();
0086
0087     unflatten_and_copy_device_tree();
0088
0089 #ifdef CONFIG_SMP
0090     setup_smp();
0091 #endif
0092
0093     sparse_init();
0094
0095     fixaddr_init();
0096
0097 #ifdef CONFIG_HIGHMEM
0098     kmap_init();
0099 #endif
0100 }
0101
0102 unsigned long va_pa_offset;
0103 EXPORT_SYMBOL(va_pa_offset);
0104
0105 static inline unsigned long read_mmu_msa(void)
0106 {
0107 #ifdef CONFIG_PAGE_OFFSET_80000000
0108     return read_mmu_msa0();
0109 #endif
0110
0111 #ifdef CONFIG_PAGE_OFFSET_A0000000
0112     return read_mmu_msa1();
0113 #endif
0114 }
0115
0116 asmlinkage __visible void __init csky_start(unsigned int unused,
0117                         void *dtb_start)
0118 {
0119     /* Clean up bss section */
0120     memset(__bss_start, 0, __bss_stop - __bss_start);
0121
0122     va_pa_offset = read_mmu_msa() & ~(SSEG_SIZE - 1);
0123
0124     pre_trap_init();
0125
0126     if (dtb_start == NULL)
0127         early_init_dt_scan(__dtb_start);
0128     else
0129         early_init_dt_scan(dtb_start);
0130
0131     start_kernel();
0132
0133     asm volatile("br .\n");
0134 }