linux-imx

// SPDX-License-Identifier: GPL-2.0

/*

 *  linux/drivers/char/mem.c

 *

 *  Copyright (C) 1991, 1992  Linus Torvalds

 *

 *  Added devfs support.

 *    Jan-11-1998, C. Scott Ananian <cananian@alumni.princeton.edu>

 *  Shared /dev/zero mmapping support, Feb 2000, Kanoj Sarcar <kanoj@sgi.com>

 */

​

#include <linux/mm.h>

#include <linux/miscdevice.h>

#include <linux/slab.h>

#include <linux/vmalloc.h>

#include <linux/mman.h>

#include <linux/random.h>

#include <linux/init.h>

#include <linux/raw.h>

#include <linux/tty.h>

#include <linux/capability.h>

#include <linux/ptrace.h>

#include <linux/device.h>

#include <linux/highmem.h>

#include <linux/backing-dev.h>

#include <linux/shmem_fs.h>

#include <linux/splice.h>

#include <linux/pfn.h>

#include <linux/export.h>

#include <linux/io.h>

#include <linux/uio.h>

​

#include <linux/uaccess.h>

​

#ifdef CONFIG_IA64

# include <linux/efi.h>

#endif

​

#define DEVPORT_MINOR   4

​

static inline unsigned long size_inside_page(unsigned long start,

                         unsigned long size)

{

    unsigned long sz;

​

    sz = PAGE_SIZE - (start & (PAGE_SIZE - 1));

​

    return min(sz, size);

}

​

#ifndef ARCH_HAS_VALID_PHYS_ADDR_RANGE

static inline int valid_phys_addr_range(phys_addr_t addr, size_t count)

{

    return addr + count <= __pa(high_memory);

}

​

static inline int valid_mmap_phys_addr_range(unsigned long pfn, size_t size)

{

    return 1;

}

#endif

​

#ifdef CONFIG_STRICT_DEVMEM

static inline int page_is_allowed(unsigned long pfn)

{

    return devmem_is_allowed(pfn);

}

static inline int range_is_allowed(unsigned long pfn, unsigned long size)

{

    u64 from = ((u64)pfn) << PAGE_SHIFT;

    u64 to = from + size;

    u64 cursor = from;

​

    while (cursor < to) {

        if (!devmem_is_allowed(pfn))

            return 0;

        cursor += PAGE_SIZE;

        pfn++;

    }

    return 1;

}

#else

static inline int page_is_allowed(unsigned long pfn)

{

    return 1;

}

static inline int range_is_allowed(unsigned long pfn, unsigned long size)

{

    return 1;

}

#endif

​