// SPDX-License-Identifier: GPL-2.0// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd. #include <linux/console.h>#include <linux/memblock.h>#include <linux/initrd.h>#include <linux/of.h>#include <linux/of_fdt.h>#include <linux/start_kernel.h>#include <linux/dma-map-ops.h>#include <asm/sections.h>#include <asm/mmu_context.h>#include <asm/pgalloc.h> #ifdef CONFIG_BLK_DEV_INITRDstatic void __init setup_initrd(void){	unsigned long size; 	if (initrd_start >= initrd_end) {		pr_err("initrd not found or empty");		goto disable;	} 	if (__pa(initrd_end) > PFN_PHYS(max_low_pfn)) {		pr_err("initrd extends beyond end of memory");		goto disable;	} 	size = initrd_end - initrd_start; 	if (memblock_is_region_reserved(__pa(initrd_start), size)) {		pr_err("INITRD: 0x%08lx+0x%08lx overlaps in-use memory region",		       __pa(initrd_start), size);		goto disable;	} 	memblock_reserve(__pa(initrd_start), size); 	pr_info("Initial ramdisk at: 0x%p (%lu bytes)\n",		(void *)(initrd_start), size); 	initrd_below_start_ok = 1; 	return; disable:	initrd_start = initrd_end = 0; 	pr_err(" - disabling initrd\n");}#endif void __init arch_zone_limits_init(unsigned long *max_zone_pfns){	max_zone_pfns[ZONE_NORMAL] = max_low_pfn;#ifdef CONFIG_HIGHMEM	max_zone_pfns[ZONE_HIGHMEM] = max_pfn;#endif} static void __init csky_memblock_init(void){	unsigned long lowmem_size = PFN_DOWN(LOWMEM_LIMIT - PHYS_OFFSET_OFFSET);	unsigned long sseg_size = PFN_DOWN(SSEG_SIZE - PHYS_OFFSET_OFFSET);	signed long size; 	memblock_reserve(__pa(_start), _end - _start); 	early_init_fdt_reserve_self();	early_init_fdt_scan_reserved_mem(); 	memblock_dump_all(); 	min_low_pfn = PFN_UP(memblock_start_of_DRAM());	max_low_pfn = max_pfn = PFN_DOWN(memblock_end_of_DRAM()); 	size = max_pfn - min_low_pfn; 	if (size >= lowmem_size) {		max_low_pfn = min_low_pfn + lowmem_size;#ifdef CONFIG_PAGE_OFFSET_80000000		write_mmu_msa1(read_mmu_msa0() + SSEG_SIZE);#endif	} else if (size > sseg_size) {		max_low_pfn = min_low_pfn + sseg_size;	} #ifdef CONFIG_BLK_DEV_INITRD	setup_initrd();#endif 	mmu_init(min_low_pfn, max_low_pfn); #ifdef CONFIG_HIGHMEM 	highstart_pfn = max_low_pfn;	highend_pfn   = max_pfn;#endif	memblock_set_current_limit(PFN_PHYS(max_low_pfn)); 	dma_contiguous_reserve(0);} void __init setup_arch(char **cmdline_p){	*cmdline_p = boot_command_line; 	console_verbose(); 	pr_info("Phys. mem: %ldMB\n",		(unsigned long) memblock_phys_mem_size()/1024/1024); 	setup_initial_init_mm(_start, _etext, _edata, _end); 	parse_early_param(); 	csky_memblock_init(); 	unflatten_and_copy_device_tree(); #ifdef CONFIG_SMP	setup_smp();#endif 	fixaddr_init(); #ifdef CONFIG_HIGHMEM	kmap_init();#endif} unsigned long va_pa_offset;EXPORT_SYMBOL(va_pa_offset); static inline unsigned long read_mmu_msa(void){#ifdef CONFIG_PAGE_OFFSET_80000000	return read_mmu_msa0();#endif #ifdef CONFIG_PAGE_OFFSET_A0000000	return read_mmu_msa1();#endif} asmlinkage __visible void __init csky_start(unsigned int unused,					    void *dtb_start){	/* Clean up bss section */	memset(__bss_start, 0, __bss_stop - __bss_start); 	va_pa_offset = read_mmu_msa() & ~(SSEG_SIZE - 1); 	pre_trap_init(); 	if (dtb_start == NULL)		early_init_dt_scan(__dtb_start, __pa(dtb_start));	else		early_init_dt_scan(dtb_start, __pa(dtb_start)); 	start_kernel(); 	asm volatile("br .\n");}