// SPDX-License-Identifier: GPL-2.0-only
/*
 * Support for Partition Mobility/Migration
 *
 * Copyright (C) 2010 Nathan Fontenot
 * Copyright (C) 2010 IBM Corporation
 */


#define pr_fmt(fmt) "mobility: " fmt

#include <linux/cpu.h>
#include <linux/kernel.h>
#include <linux/kobject.h>
#include <linux/sched.h>
#include <linux/smp.h>
#include <linux/stat.h>
#include <linux/completion.h>
#include <linux/device.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/stringify.h>

#include <asm/machdep.h>
#include <asm/rtas.h>
#include "pseries.h"
#include "../../kernel/cacheinfo.h"

static struct kobject *mobility_kobj;

struct update_props_workarea {
        __be32 phandle;
        __be32 state;
        __be64 reserved;
        __be32 nprops;
} __packed;

#define NODE_ACTION_MASK        0xff000000
#define NODE_COUNT_MASK         0x00ffffff

#define DELETE_DT_NODE  0x01000000
#define UPDATE_DT_NODE  0x02000000
#define ADD_DT_NODE     0x03000000

#define MIGRATION_SCOPE (1)
#define PRRN_SCOPE -2

static int mobility_rtas_call(int token, char *buf, s32 scope)
{
        int rc;

        spin_lock(&rtas_data_buf_lock);

        memcpy(rtas_data_buf, buf, RTAS_DATA_BUF_SIZE);
        rc = rtas_call(token, 2, 1, NULL, rtas_data_buf, scope);
        memcpy(buf, rtas_data_buf, RTAS_DATA_BUF_SIZE);

        spin_unlock(&rtas_data_buf_lock);
        return rc;
}

static int delete_dt_node(__be32 phandle)
{
        struct device_node *dn;

        dn = of_find_node_by_phandle(be32_to_cpu(phandle));
        if (!dn)
                return -ENOENT;

        pr_debug("removing node %pOFfp\n", dn);

        dlpar_detach_node(dn);
        of_node_put(dn);
        return 0;
}

static int update_dt_property(struct device_node *dn, struct property **prop,
                              const char *name, u32 vd, char *value)
{
        struct property *new_prop = *prop;
        int more = 0;

        /* A negative 'vd' value indicates that only part of the new property
         * value is contained in the buffer and we need to call
         * ibm,update-properties again to get the rest of the value.
         *
         * A negative value is also the two's compliment of the actual value.
         */
        if (vd & 0x80000000) {
                vd = ~vd + 1;
                more = 1;
        }

        if (new_prop) {
                /* partial property fixup */
                char *new_data = kzalloc(new_prop->length + vd, GFP_KERNEL);
                if (!new_data)
                        return -ENOMEM;

                memcpy(new_data, new_prop->value, new_prop->length);
                memcpy(new_data + new_prop->length, value, vd);

                kfree(new_prop->value);
                new_prop->value = new_data;
                new_prop->length += vd;
        } else {
                new_prop = kzalloc(sizeof(*new_prop), GFP_KERNEL);
                if (!new_prop)
                        return -ENOMEM;

                new_prop->name = kstrdup(name, GFP_KERNEL);
                if (!new_prop->name) {
                        kfree(new_prop);
                        return -ENOMEM;
                }

                new_prop->length = vd;
                new_prop->value = kzalloc(new_prop->length, GFP_KERNEL);
                if (!new_prop->value) {
                        kfree(new_prop->name);
                        kfree(new_prop);
                        return -ENOMEM;
                }

                memcpy(new_prop->value, value, vd);
                *prop = new_prop;
        }

        if (!more) {
                pr_debug("updating node %pOF property %s\n", dn, name);
                of_update_property(dn, new_prop);
                *prop = NULL;
        }

        return 0;
}

static int update_dt_node(__be32 phandle, s32 scope)
{
        struct update_props_workarea *upwa;
        struct device_node *dn;
        struct property *prop = NULL;
        int i, rc, rtas_rc;
        char *prop_data;
        char *rtas_buf;
        int update_properties_token;
        u32 nprops;
        u32 vd;

        update_properties_token = rtas_token("ibm,update-properties");
        if (update_properties_token == RTAS_UNKNOWN_SERVICE)
                return -EINVAL;

        rtas_buf = kzalloc(RTAS_DATA_BUF_SIZE, GFP_KERNEL);
        if (!rtas_buf)
                return -ENOMEM;

        dn = of_find_node_by_phandle(be32_to_cpu(phandle));
        if (!dn) {
                kfree(rtas_buf);
                return -ENOENT;
        }

        upwa = (struct update_props_workarea *)&rtas_buf[0];
        upwa->phandle = phandle;

        do {
                rtas_rc = mobility_rtas_call(update_properties_token, rtas_buf,
                                        scope);
                if (rtas_rc < 0)
                        break;

                prop_data = rtas_buf + sizeof(*upwa);
                nprops = be32_to_cpu(upwa->nprops);

                /* On the first call to ibm,update-properties for a node the
                 * the first property value descriptor contains an empty
                 * property name, the property value length encoded as u32,
                 * and the property value is the node path being updated.
                 */
                if (*prop_data == 0) {
                        prop_data++;
                        vd = be32_to_cpu(*(__be32 *)prop_data);
                        prop_data += vd + sizeof(vd);
                        nprops--;
                }

                for (i = 0; i < nprops; i++) {
                        char *prop_name;

                        prop_name = prop_data;
                        prop_data += strlen(prop_name) + 1;
                        vd = be32_to_cpu(*(__be32 *)prop_data);
                        prop_data += sizeof(vd);

                        switch (vd) {
                        case 0x00000000:
                                /* name only property, nothing to do */
                                break;

                        case 0x80000000:
                                of_remove_property(dn, of_find_property(dn,
                                                        prop_name, NULL));
                                prop = NULL;
                                break;

                        default:
                                rc = update_dt_property(dn, &prop, prop_name,
                                                        vd, prop_data);
                                if (rc) {
                                        printk(KERN_ERR "Could not update %s"
                                               " property\n", prop_name);
                                }

                                prop_data += vd;
                        }

                        cond_resched();
                }

                cond_resched();
        } while (rtas_rc == 1);

        of_node_put(dn);
        kfree(rtas_buf);
        return 0;
}

static int add_dt_node(__be32 parent_phandle, __be32 drc_index)
{
        struct device_node *dn;
        struct device_node *parent_dn;
        int rc;

        parent_dn = of_find_node_by_phandle(be32_to_cpu(parent_phandle));
        if (!parent_dn)
                return -ENOENT;

        dn = dlpar_configure_connector(drc_index, parent_dn);
        if (!dn) {
                of_node_put(parent_dn);
                return -ENOENT;
        }

        rc = dlpar_attach_node(dn, parent_dn);
        if (rc)
                dlpar_free_cc_nodes(dn);

        pr_debug("added node %pOFfp\n", dn);

        of_node_put(parent_dn);
        return rc;
}

int pseries_devicetree_update(s32 scope)
{
        char *rtas_buf;
        __be32 *data;
        int update_nodes_token;
        int rc;

        update_nodes_token = rtas_token("ibm,update-nodes");
        if (update_nodes_token == RTAS_UNKNOWN_SERVICE)
                return -EINVAL;

        rtas_buf = kzalloc(RTAS_DATA_BUF_SIZE, GFP_KERNEL);
        if (!rtas_buf)
                return -ENOMEM;

        do {
                rc = mobility_rtas_call(update_nodes_token, rtas_buf, scope);
                if (rc && rc != 1)
                        break;

                data = (__be32 *)rtas_buf + 4;
                while (be32_to_cpu(*data) & NODE_ACTION_MASK) {
                        int i;
                        u32 action = be32_to_cpu(*data) & NODE_ACTION_MASK;
                        u32 node_count = be32_to_cpu(*data) & NODE_COUNT_MASK;

                        data++;

                        for (i = 0; i < node_count; i++) {
                                __be32 phandle = *data++;
                                __be32 drc_index;

                                switch (action) {
                                case DELETE_DT_NODE:
                                        delete_dt_node(phandle);
                                        break;
                                case UPDATE_DT_NODE:
                                        update_dt_node(phandle, scope);
                                        break;
                                case ADD_DT_NODE:
                                        drc_index = *data++;
                                        add_dt_node(phandle, drc_index);
                                        break;
                                }

                                cond_resched();
                        }
                }

                cond_resched();
        } while (rc == 1);

        kfree(rtas_buf);
        return rc;
}

void post_mobility_fixup(void)
{
        int rc;
        int activate_fw_token;

        activate_fw_token = rtas_token("ibm,activate-firmware");
        if (activate_fw_token == RTAS_UNKNOWN_SERVICE) {
                printk(KERN_ERR "Could not make post-mobility "
                       "activate-fw call.\n");
                return;
        }

        do {
                rc = rtas_call(activate_fw_token, 0, 1, NULL);
        } while (rtas_busy_delay(rc));

        if (rc)
                printk(KERN_ERR "Post-mobility activate-fw failed: %d\n", rc);

        /*
         * We don't want CPUs to go online/offline while the device
         * tree is being updated.
         */
        cpus_read_lock();

        /*
         * It's common for the destination firmware to replace cache
         * nodes.  Release all of the cacheinfo hierarchy's references
         * before updating the device tree.
         */
        cacheinfo_teardown();

        rc = pseries_devicetree_update(MIGRATION_SCOPE);
        if (rc)
                printk(KERN_ERR "Post-mobility device tree update "
                        "failed: %d\n", rc);

        cacheinfo_rebuild();

        cpus_read_unlock();

        /* Possibly switch to a new RFI flush type */
        pseries_setup_rfi_flush();

        /* Reinitialise system information for hv-24x7 */
        read_24x7_sys_info();

        return;
}

static ssize_t migration_store(struct class *class,
                               struct class_attribute *attr, const char *buf,
                               size_t count)
{
        u64 streamid;
        int rc;

        rc = kstrtou64(buf, 0, &streamid);
        if (rc)
                return rc;

        do {
                rc = rtas_ibm_suspend_me(streamid);
                if (rc == -EAGAIN)
                        ssleep(1);
        } while (rc == -EAGAIN);

        if (rc)
                return rc;

        post_mobility_fixup();

        return count;
}

/*
 * Used by drmgr to determine the kernel behavior of the migration interface.
 *
 * Version 1: Performs all PAPR requirements for migration including
 *      firmware activation and device tree update.
 */
#define MIGRATION_API_VERSION   1

static CLASS_ATTR_WO(migration);
static CLASS_ATTR_STRING(api_version, 0444, __stringify(MIGRATION_API_VERSION));

static int __init mobility_sysfs_init(void)
{
        int rc;

        mobility_kobj = kobject_create_and_add("mobility", kernel_kobj);
        if (!mobility_kobj)
                return -ENOMEM;

        rc = sysfs_create_file(mobility_kobj, &class_attr_migration.attr);
        if (rc)
                pr_err("unable to create migration sysfs file (%d)\n", rc);

        rc = sysfs_create_file(mobility_kobj, &class_attr_api_version.attr.attr);
        if (rc)
                pr_err("unable to create api_version sysfs file (%d)\n", rc);

        return 0;
}
machine_device_initcall(pseries, mobility_sysfs_init);