linux-imx

// SPDX-License-Identifier: GPL-2.0

/* Copyright(c) 2016-2019 Intel Corporation. All rights reserved. */

#include <linux/memremap.h>

#include <linux/pagemap.h>

#include <linux/memory.h>

#include <linux/module.h>

#include <linux/device.h>

#include <linux/pfn_t.h>

#include <linux/slab.h>

#include <linux/dax.h>

#include <linux/fs.h>

#include <linux/mm.h>

#include <linux/mman.h>

#include "dax-private.h"

#include "bus.h"

​

int dev_dax_kmem_probe(struct device *dev)

{

    struct dev_dax *dev_dax = to_dev_dax(dev);

    struct resource *res = &dev_dax->region->res;

    resource_size_t kmem_start;

    resource_size_t kmem_size;

    resource_size_t kmem_end;

    struct resource *new_res;

    int numa_node;

    int rc;

​

    /*

     * Ensure good NUMA information for the persistent memory.

     * Without this check, there is a risk that slow memory

     * could be mixed in a node with faster memory, causing

     * unavoidable performance issues.

     */

    numa_node = dev_dax->target_node;

    if (numa_node < 0) {

        dev_warn(dev, "rejecting DAX region %pR with invalid node: %d\n",

             res, numa_node);

        return -EINVAL;

    }

​

    /* Hotplug starting at the beginning of the next block: */

    kmem_start = ALIGN(res->start, memory_block_size_bytes());

​

    kmem_size = resource_size(res);

    /* Adjust the size down to compensate for moving up kmem_start: */

    kmem_size -= kmem_start - res->start;

    /* Align the size down to cover only complete blocks: */

    kmem_size &= ~(memory_block_size_bytes() - 1);

    kmem_end = kmem_start + kmem_size;

​

    /* Region is permanently reserved.  Hot-remove not yet implemented. */

    new_res = request_mem_region(kmem_start, kmem_size, dev_name(dev));

    if (!new_res) {

        dev_warn(dev, "could not reserve region [%pa-%pa]\n",

             &kmem_start, &kmem_end);

        return -EBUSY;

    }

​

    /*

     * Set flags appropriate for System RAM.  Leave ..._BUSY clear

     * so that add_memory() can add a child resource.  Do not

     * inherit flags from the parent since it may set new flags

     * unknown to us that will break add_memory() below.