// SPDX-License-Identifier: GPL-2.0
/*
 *  linux/arch/sparc/mm/init.c
 *
 *  Copyright (C) 1995 David S. Miller (davem@caip.rutgers.edu)
 *  Copyright (C) 1995 Eddie C. Dost (ecd@skynet.be)
 *  Copyright (C) 1998 Jakub Jelinek (jj@sunsite.mff.cuni.cz)
 *  Copyright (C) 2000 Anton Blanchard (anton@samba.org)
 */

#include <linux/module.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/ptrace.h>
#include <linux/mman.h>
#include <linux/mm.h>
#include <linux/swap.h>
#include <linux/initrd.h>
#include <linux/init.h>
#include <linux/highmem.h>
#include <linux/memblock.h>
#include <linux/pagemap.h>
#include <linux/poison.h>
#include <linux/gfp.h>

#include <asm/sections.h>
#include <asm/page.h>
#include <asm/vaddrs.h>
#include <asm/setup.h>
#include <asm/tlb.h>
#include <asm/prom.h>
#include <asm/leon.h>

#include "mm_32.h"

static unsigned long *sparc_valid_addr_bitmap;

unsigned long phys_base;
EXPORT_SYMBOL(phys_base);

unsigned long pfn_base;
EXPORT_SYMBOL(pfn_base);

struct sparc_phys_banks sp_banks[SPARC_PHYS_BANKS+1];

/* Initial ramdisk setup */
extern unsigned int sparc_ramdisk_image;
extern unsigned int sparc_ramdisk_size;

unsigned long highstart_pfn, highend_pfn;

unsigned long last_valid_pfn;

unsigned long calc_highpages(void)
{
        int i;
        int nr = 0;

        for (i = 0; sp_banks[i].num_bytes != 0; i++) {
                unsigned long start_pfn = sp_banks[i].base_addr >> PAGE_SHIFT;
                unsigned long end_pfn = (sp_banks[i].base_addr + sp_banks[i].num_bytes) >> PAGE_SHIFT;

                if (end_pfn <= max_low_pfn)
                        continue;

                if (start_pfn < max_low_pfn)
                        start_pfn = max_low_pfn;

                nr += end_pfn - start_pfn;
        }

        return nr;
}

static unsigned long calc_max_low_pfn(void)
{
        int i;
        unsigned long tmp = pfn_base + (SRMMU_MAXMEM >> PAGE_SHIFT);
        unsigned long curr_pfn, last_pfn;

        last_pfn = (sp_banks[0].base_addr + sp_banks[0].num_bytes) >> PAGE_SHIFT;
        for (i = 1; sp_banks[i].num_bytes != 0; i++) {
                curr_pfn = sp_banks[i].base_addr >> PAGE_SHIFT;

                if (curr_pfn >= tmp) {
                        if (last_pfn < tmp)
                                tmp = last_pfn;
                        break;
                }

                last_pfn = (sp_banks[i].base_addr + sp_banks[i].num_bytes) >> PAGE_SHIFT;
        }

        return tmp;
}

static void __init find_ramdisk(unsigned long end_of_phys_memory)
{
#ifdef CONFIG_BLK_DEV_INITRD
        unsigned long size;

        /* Now have to check initial ramdisk, so that it won't pass
         * the end of memory
         */
        if (sparc_ramdisk_image) {
                if (sparc_ramdisk_image >= (unsigned long)&_end - 2 * PAGE_SIZE)
                        sparc_ramdisk_image -= KERNBASE;
                initrd_start = sparc_ramdisk_image + phys_base;
                initrd_end = initrd_start + sparc_ramdisk_size;
                if (initrd_end > end_of_phys_memory) {
                        printk(KERN_CRIT "initrd extends beyond end of memory "
                               "(0x%016lx > 0x%016lx)\ndisabling initrd\n",
                               initrd_end, end_of_phys_memory);
                        initrd_start = 0;
                } else {
                        /* Reserve the initrd image area. */
                        size = initrd_end - initrd_start;
                        memblock_reserve(initrd_start, size);

                        initrd_start = (initrd_start - phys_base) + PAGE_OFFSET;
                        initrd_end = (initrd_end - phys_base) + PAGE_OFFSET;
                }
        }
#endif
}

unsigned long __init bootmem_init(unsigned long *pages_avail)
{
        unsigned long start_pfn, bytes_avail, size;
        unsigned long end_of_phys_memory = 0;
        unsigned long high_pages = 0;
        int i;

        memblock_set_bottom_up(true);
        memblock_allow_resize();

        bytes_avail = 0UL;
        for (i = 0; sp_banks[i].num_bytes != 0; i++) {
                end_of_phys_memory = sp_banks[i].base_addr +
                        sp_banks[i].num_bytes;
                bytes_avail += sp_banks[i].num_bytes;
                if (cmdline_memory_size) {
                        if (bytes_avail > cmdline_memory_size) {
                                unsigned long slack = bytes_avail - cmdline_memory_size;

                                bytes_avail -= slack;
                                end_of_phys_memory -= slack;

                                sp_banks[i].num_bytes -= slack;
                                if (sp_banks[i].num_bytes == 0) {
                                        sp_banks[i].base_addr = 0xdeadbeef;
                                } else {
                                        memblock_add(sp_banks[i].base_addr,
                                                     sp_banks[i].num_bytes);
                                        sp_banks[i+1].num_bytes = 0;
                                        sp_banks[i+1].base_addr = 0xdeadbeef;
                                }
                                break;
                        }
                }
                memblock_add(sp_banks[i].base_addr, sp_banks[i].num_bytes);
        }

        /* Start with page aligned address of last symbol in kernel
         * image.
         */
        start_pfn  = (unsigned long)__pa(PAGE_ALIGN((unsigned long) &_end));

        /* Now shift down to get the real physical page frame number. */
        start_pfn >>= PAGE_SHIFT;

        max_pfn = end_of_phys_memory >> PAGE_SHIFT;

        max_low_pfn = max_pfn;
        highstart_pfn = highend_pfn = max_pfn;

        if (max_low_pfn > pfn_base + (SRMMU_MAXMEM >> PAGE_SHIFT)) {
                highstart_pfn = pfn_base + (SRMMU_MAXMEM >> PAGE_SHIFT);
                max_low_pfn = calc_max_low_pfn();
                high_pages = calc_highpages();
                printk(KERN_NOTICE "%ldMB HIGHMEM available.\n",
                    high_pages >> (20 - PAGE_SHIFT));
        }

        find_ramdisk(end_of_phys_memory);

        /* Reserve the kernel text/data/bss. */
        size = (start_pfn << PAGE_SHIFT) - phys_base;
        memblock_reserve(phys_base, size);
        memblock_add(phys_base, size);

        size = memblock_phys_mem_size() - memblock_reserved_size();
        *pages_avail = (size >> PAGE_SHIFT) - high_pages;

        /* Only allow low memory to be allocated via memblock allocation */
        memblock_set_current_limit(max_low_pfn << PAGE_SHIFT);

        return max_pfn;
}

/*
 * paging_init() sets up the page tables: We call the MMU specific
 * init routine based upon the Sun model type on the Sparc.
 *
 */
void __init paging_init(void)
{
        srmmu_paging_init();
        prom_build_devicetree();
        of_fill_in_cpu_data();
        device_scan();
}

static void __init taint_real_pages(void)
{
        int i;

        for (i = 0; sp_banks[i].num_bytes; i++) {
                unsigned long start, end;

                start = sp_banks[i].base_addr;
                end = start + sp_banks[i].num_bytes;

                while (start < end) {
                        set_bit(start >> 20, sparc_valid_addr_bitmap);
                        start += PAGE_SIZE;
                }
        }
}

void __init arch_mm_preinit(void)
{
        int i;

        if (PKMAP_BASE+LAST_PKMAP*PAGE_SIZE >= FIXADDR_START) {
                prom_printf("BUG: fixmap and pkmap areas overlap\n");
                prom_printf("pkbase: 0x%lx pkend: 0x%lx fixstart 0x%lx\n",
                       PKMAP_BASE,
                       (unsigned long)PKMAP_BASE+LAST_PKMAP*PAGE_SIZE,
                       FIXADDR_START);
                prom_printf("Please mail sparclinux@vger.kernel.org.\n");
                prom_halt();
        }


        /* Saves us work later. */
        memset((void *)empty_zero_page, 0, PAGE_SIZE);

        i = last_valid_pfn >> ((20 - PAGE_SHIFT) + 5);
        i += 1;
        sparc_valid_addr_bitmap = (unsigned long *)
                memblock_alloc(i << 2, SMP_CACHE_BYTES);

        if (sparc_valid_addr_bitmap == NULL) {
                prom_printf("mem_init: Cannot alloc valid_addr_bitmap.\n");
                prom_halt();
        }
        memset(sparc_valid_addr_bitmap, 0, i << 2);

        taint_real_pages();
}

void sparc_flush_page_to_ram(struct page *page)
{
        unsigned long vaddr = (unsigned long)page_address(page);

        __flush_page_to_ram(vaddr);
}
EXPORT_SYMBOL(sparc_flush_page_to_ram);

void sparc_flush_folio_to_ram(struct folio *folio)
{
        unsigned long vaddr = (unsigned long)folio_address(folio);
        unsigned int i, nr = folio_nr_pages(folio);

        for (i = 0; i < nr; i++)
                __flush_page_to_ram(vaddr + i * PAGE_SIZE);
}
EXPORT_SYMBOL(sparc_flush_folio_to_ram);

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