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#ifdef CONFIG_BLK_DEV_INITRD
 16static void __init setup_initrd(void)
 17{
 18	unsigned long size;
 19
 20	if (initrd_start >= initrd_end) {
 21		pr_err("initrd not found or empty");
 22		goto disable;
 23	}
 24
 25	if (__pa(initrd_end) > PFN_PHYS(max_low_pfn)) {
 26		pr_err("initrd extends beyond end of memory");
 27		goto disable;
 28	}
 29
 30	size = initrd_end - initrd_start;
 31
 32	if (memblock_is_region_reserved(__pa(initrd_start), size)) {
 33		pr_err("INITRD: 0x%08lx+0x%08lx overlaps in-use memory region",
 34		       __pa(initrd_start), size);
 35		goto disable;
 36	}
 37
 38	memblock_reserve(__pa(initrd_start), size);
 39
 40	pr_info("Initial ramdisk at: 0x%p (%lu bytes)\n",
 41		(void *)(initrd_start), size);
 42
 43	initrd_below_start_ok = 1;
 44
 45	return;
 46
 47disable:
 48	initrd_start = initrd_end = 0;
 49
 50	pr_err(" - disabling initrd\n");
 51}
 52#endif
 53
 54static void __init csky_memblock_init(void)
 55{
 56	unsigned long lowmem_size = PFN_DOWN(LOWMEM_LIMIT - PHYS_OFFSET_OFFSET);
 57	unsigned long sseg_size = PFN_DOWN(SSEG_SIZE - PHYS_OFFSET_OFFSET);
 58	unsigned long max_zone_pfn[MAX_NR_ZONES] = { 0 };
 59	signed long size;
 60
 61	memblock_reserve(__pa(_start), _end - _start);
 62
 63	early_init_fdt_reserve_self();
 64	early_init_fdt_scan_reserved_mem();
 65
 66	memblock_dump_all();
 67
 68	min_low_pfn = PFN_UP(memblock_start_of_DRAM());
 69	max_low_pfn = max_pfn = PFN_DOWN(memblock_end_of_DRAM());
 70
 71	size = max_pfn - min_low_pfn;
 72
 73	if (size >= lowmem_size) {
 74		max_low_pfn = min_low_pfn + lowmem_size;
 75#ifdef CONFIG_PAGE_OFFSET_80000000
 76		write_mmu_msa1(read_mmu_msa0() + SSEG_SIZE);
 77#endif
 78	} else if (size > sseg_size) {
 79		max_low_pfn = min_low_pfn + sseg_size;
 80	}
 81
 82#ifdef CONFIG_BLK_DEV_INITRD
 83	setup_initrd();
 84#endif
 85
 86	max_zone_pfn[ZONE_NORMAL] = max_low_pfn;
 87
 88	mmu_init(min_low_pfn, max_low_pfn);
 89
 90#ifdef CONFIG_HIGHMEM
 91	max_zone_pfn[ZONE_HIGHMEM] = max_pfn;
 92
 93	highstart_pfn = max_low_pfn;
 94	highend_pfn   = max_pfn;
 95#endif
 96	memblock_set_current_limit(PFN_PHYS(max_low_pfn));
 97
 98	dma_contiguous_reserve(0);
 99
100	free_area_init(max_zone_pfn);
101}
102
103void __init setup_arch(char **cmdline_p)
104{
105	*cmdline_p = boot_command_line;
106
107	console_verbose();
108
109	pr_info("Phys. mem: %ldMB\n",
110		(unsigned long) memblock_phys_mem_size()/1024/1024);
111
112	setup_initial_init_mm(_start, _etext, _edata, _end);
113
114	parse_early_param();
115
116	csky_memblock_init();
117
118	unflatten_and_copy_device_tree();
119
120#ifdef CONFIG_SMP
121	setup_smp();
122#endif
123
124	sparse_init();
125
126	fixaddr_init();
127
128#ifdef CONFIG_HIGHMEM
129	kmap_init();
130#endif
131}
132
133unsigned long va_pa_offset;
134EXPORT_SYMBOL(va_pa_offset);
135
136static inline unsigned long read_mmu_msa(void)
137{
138#ifdef CONFIG_PAGE_OFFSET_80000000
139	return read_mmu_msa0();
140#endif
141
142#ifdef CONFIG_PAGE_OFFSET_A0000000
143	return read_mmu_msa1();
144#endif
145}
146
147asmlinkage __visible void __init csky_start(unsigned int unused,
148					    void *dtb_start)
149{
150	/* Clean up bss section */
151	memset(__bss_start, 0, __bss_stop - __bss_start);
152
153	va_pa_offset = read_mmu_msa() & ~(SSEG_SIZE - 1);
154
155	pre_trap_init();
156
157	if (dtb_start == NULL)
158		early_init_dt_scan(__dtb_start, __pa(dtb_start));
159	else
160		early_init_dt_scan(dtb_start, __pa(dtb_start));
161
162	start_kernel();
163
164	asm volatile("br .\n");
165}