// SPDX-License-Identifier: GPL-2.0
// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.

#include <linux/bug.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/pagemap.h>
#include <linux/ptrace.h>
#include <linux/mman.h>
#include <linux/mm.h>
#include <linux/highmem.h>
#include <linux/memblock.h>
#include <linux/swap.h>
#include <linux/proc_fs.h>
#include <linux/pfn.h>
#include <linux/initrd.h>

#include <asm/setup.h>
#include <asm/cachectl.h>
#include <asm/dma.h>
#include <asm/pgalloc.h>
#include <asm/mmu_context.h>
#include <asm/sections.h>
#include <asm/tlb.h>
#include <asm/cacheflush.h>

#define PTRS_KERN_TABLE \
                ((PTRS_PER_PGD - USER_PTRS_PER_PGD) * PTRS_PER_PTE)

pgd_t swapper_pg_dir[PTRS_PER_PGD] __page_aligned_bss;
pte_t invalid_pte_table[PTRS_PER_PTE] __page_aligned_bss;
pte_t kernel_pte_tables[PTRS_KERN_TABLE] __page_aligned_bss;

EXPORT_SYMBOL(invalid_pte_table);
unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)]
                                                __page_aligned_bss;
EXPORT_SYMBOL(empty_zero_page);

void free_initmem(void)
{
        free_initmem_default(-1);
}

void pgd_init(unsigned long *p)
{
        int i;

        for (i = 0; i < PTRS_PER_PGD; i++)
                p[i] = __pa(invalid_pte_table);

        flush_tlb_all();
        local_icache_inv_all(NULL);
}

void __init mmu_init(unsigned long min_pfn, unsigned long max_pfn)
{
        int i;

        for (i = 0; i < USER_PTRS_PER_PGD; i++)
                swapper_pg_dir[i].pgd = __pa(invalid_pte_table);

        for (i = USER_PTRS_PER_PGD; i < PTRS_PER_PGD; i++)
                swapper_pg_dir[i].pgd =
                        __pa(kernel_pte_tables + (PTRS_PER_PTE * (i - USER_PTRS_PER_PGD)));

        for (i = 0; i < PTRS_KERN_TABLE; i++)
                set_pte(&kernel_pte_tables[i], __pte(_PAGE_GLOBAL));

        for (i = min_pfn; i < max_pfn; i++)
                set_pte(&kernel_pte_tables[i - PFN_DOWN(va_pa_offset)], pfn_pte(i, PAGE_KERNEL));

        flush_tlb_all();
        local_icache_inv_all(NULL);

        /* Setup page mask to 4k */
        write_mmu_pagemask(0);

        setup_pgd(swapper_pg_dir, 0);
}

void __init fixrange_init(unsigned long start, unsigned long end,
                        pgd_t *pgd_base)
{
        pgd_t *pgd;
        pud_t *pud;
        pmd_t *pmd;
        pte_t *pte;
        int i, j, k;
        unsigned long vaddr;

        vaddr = start;
        i = pgd_index(vaddr);
        j = pud_index(vaddr);
        k = pmd_index(vaddr);
        pgd = pgd_base + i;

        for ( ; (i < PTRS_PER_PGD) && (vaddr != end); pgd++, i++) {
                pud = (pud_t *)pgd;
                for ( ; (j < PTRS_PER_PUD) && (vaddr != end); pud++, j++) {
                        pmd = (pmd_t *)pud;
                        for (; (k < PTRS_PER_PMD) && (vaddr != end); pmd++, k++) {
                                if (pmd_none(*pmd)) {
                                        pte = (pte_t *) memblock_alloc_low(PAGE_SIZE, PAGE_SIZE);
                                        if (!pte)
                                                panic("%s: Failed to allocate %lu bytes align=%lx\n",
                                                      __func__, PAGE_SIZE,
                                                      PAGE_SIZE);

                                        set_pmd(pmd, __pmd(__pa(pte)));
                                        BUG_ON(pte != pte_offset_kernel(pmd, 0));
                                }
                                vaddr += PMD_SIZE;
                        }
                        k = 0;
                }
                j = 0;
        }
}

void __init fixaddr_init(void)
{
        unsigned long vaddr;

        vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK;
        fixrange_init(vaddr, vaddr + PMD_SIZE, swapper_pg_dir);
}

static const pgprot_t protection_map[16] = {
        [VM_NONE]                                       = PAGE_NONE,
        [VM_READ]                                       = PAGE_READ,
        [VM_WRITE]                                      = PAGE_READ,
        [VM_WRITE | VM_READ]                            = PAGE_READ,
        [VM_EXEC]                                       = PAGE_READ,
        [VM_EXEC | VM_READ]                             = PAGE_READ,
        [VM_EXEC | VM_WRITE]                            = PAGE_READ,
        [VM_EXEC | VM_WRITE | VM_READ]                  = PAGE_READ,
        [VM_SHARED]                                     = PAGE_NONE,
        [VM_SHARED | VM_READ]                           = PAGE_READ,
        [VM_SHARED | VM_WRITE]                          = PAGE_WRITE,
        [VM_SHARED | VM_WRITE | VM_READ]                = PAGE_WRITE,
        [VM_SHARED | VM_EXEC]                           = PAGE_READ,
        [VM_SHARED | VM_EXEC | VM_READ]                 = PAGE_READ,
        [VM_SHARED | VM_EXEC | VM_WRITE]                = PAGE_WRITE,
        [VM_SHARED | VM_EXEC | VM_WRITE | VM_READ]      = PAGE_WRITE
};
DECLARE_VM_GET_PAGE_PROT