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
 17struct 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
 27static 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
 72void __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
102unsigned long va_pa_offset;
103EXPORT_SYMBOL(va_pa_offset);
104
105static 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
116asmlinkage __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}