// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright(c) 2013-2015 Intel Corporation. All rights reserved.
 */
#include <linux/memregion.h>
#include <linux/cpumask.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/nd.h>
#include "nd-core.h"
#include "nd.h"

static int nd_region_probe(struct device *dev)
{
        int err, rc;
        static unsigned long once;
        struct nd_region_data *ndrd;
        struct nd_region *nd_region = to_nd_region(dev);
        struct range range = {
                .start = nd_region->ndr_start,
                .end = nd_region->ndr_start + nd_region->ndr_size - 1,
        };

        if (nd_region->num_lanes > num_online_cpus()
                        && nd_region->num_lanes < num_possible_cpus()
                        && !test_and_set_bit(0, &once)) {
                dev_dbg(dev, "online cpus (%d) < concurrent i/o lanes (%d) < possible cpus (%d)\n",
                                num_online_cpus(), nd_region->num_lanes,
                                num_possible_cpus());
                dev_dbg(dev, "setting nr_cpus=%d may yield better libnvdimm device performance\n",
                                nd_region->num_lanes);
        }

        rc = nd_region_activate(nd_region);
        if (rc)
                return rc;

        if (devm_init_badblocks(dev, &nd_region->bb))
                return -ENODEV;
        nd_region->bb_state =
                sysfs_get_dirent(nd_region->dev.kobj.sd, "badblocks");
        if (!nd_region->bb_state)
                dev_warn(dev, "'badblocks' notification disabled\n");
        nvdimm_badblocks_populate(nd_region, &nd_region->bb, &range);

        rc = nd_region_register_namespaces(nd_region, &err);
        if (rc < 0)
                return rc;

        ndrd = dev_get_drvdata(dev);
        ndrd->ns_active = rc;
        ndrd->ns_count = rc + err;

        if (rc && err && rc == err)
                return -ENODEV;

        nd_region->btt_seed = nd_btt_create(nd_region);
        nd_region->pfn_seed = nd_pfn_create(nd_region);
        nd_region->dax_seed = nd_dax_create(nd_region);
        if (err == 0)
                return 0;

        /*
         * Given multiple namespaces per region, we do not want to
         * disable all the successfully registered peer namespaces upon
         * a single registration failure.  If userspace is missing a
         * namespace that it expects it can disable/re-enable the region
         * to retry discovery after correcting the failure.
         * <regionX>/namespaces returns the current
         * "<async-registered>/<total>" namespace count.
         */
        dev_err(dev, "failed to register %d namespace%s, continuing...\n",
                        err, str_plural(err));
        return 0;
}

static int child_unregister(struct device *dev, void *data)
{
        nd_device_unregister(dev, ND_SYNC);
        return 0;
}

static void nd_region_remove(struct device *dev)
{
        struct nd_region *nd_region = to_nd_region(dev);

        device_for_each_child(dev, NULL, child_unregister);

        /* flush attribute readers and disable */
        scoped_guard(nvdimm_bus, dev) {
                nd_region->ns_seed = NULL;
                nd_region->btt_seed = NULL;
                nd_region->pfn_seed = NULL;
                nd_region->dax_seed = NULL;
                dev_set_drvdata(dev, NULL);
        }

        /*
         * Note, this assumes device_lock() context to not race
         * nd_region_notify()
         */
        sysfs_put(nd_region->bb_state);
        nd_region->bb_state = NULL;

        /*
         * Try to flush caches here since a disabled region may be subject to
         * secure erase while disabled, and previous dirty data should not be
         * written back to a new instance of the region. This only matters on
         * bare metal where security commands are available, so silent failure
         * here is ok.
         */
        if (cpu_cache_has_invalidate_memregion())
                cpu_cache_invalidate_all();
}

static int child_notify(struct device *dev, void *data)
{
        nd_device_notify(dev, *(enum nvdimm_event *) data);
        return 0;
}

static void nd_region_notify(struct device *dev, enum nvdimm_event event)
{
        if (event == NVDIMM_REVALIDATE_POISON) {
                struct nd_region *nd_region = to_nd_region(dev);

                if (is_memory(&nd_region->dev)) {
                        struct range range = {
                                .start = nd_region->ndr_start,
                                .end = nd_region->ndr_start +
                                        nd_region->ndr_size - 1,
                        };

                        nvdimm_badblocks_populate(nd_region,
                                        &nd_region->bb, &range);
                        if (nd_region->bb_state)
                                sysfs_notify_dirent(nd_region->bb_state);
                }
        }
        device_for_each_child(dev, &event, child_notify);
}

static struct nd_device_driver nd_region_driver = {
        .probe = nd_region_probe,
        .remove = nd_region_remove,
        .notify = nd_region_notify,
        .drv = {
                .name = "nd_region",
        },
        .type = ND_DRIVER_REGION_BLK | ND_DRIVER_REGION_PMEM,
};

int __init nd_region_init(void)
{
        return nd_driver_register(&nd_region_driver);
}

void nd_region_exit(void)
{
        driver_unregister(&nd_region_driver.drv);
}

MODULE_ALIAS_ND_DEVICE(ND_DEVICE_REGION_PMEM);