dlpar.c

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/*
 * Support for dynamic reconfiguration for PCI, Memory, and CPU
 * Hotplug and Dynamic Logical Partitioning on RPA platforms.
 *
 * Copyright (C) 2009 Nathan Fontenot
 * Copyright (C) 2009 IBM Corporation
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License version
 * 2 as published by the Free Software Foundation.
 */

#include <linux/kernel.h>
#include <linux/kref.h>
#include <linux/notifier.h>
#include <linux/proc_fs.h>
#include <linux/spinlock.h>
#include <linux/cpu.h>
#include <linux/slab.h>
#include "offline_states.h"

#include <asm/prom.h>
#include <asm/machdep.h>
#include <asm/uaccess.h>
#include <asm/rtas.h>
#include <asm/pSeries_reconfig.h>

struct cc_workarea {
    u32 drc_index;
    u32 zero;
    u32 name_offset;
    u32 prop_length;
    u32 prop_offset;
};

void dlpar_free_cc_property(struct property *prop)
{
    kfree(prop->name);
    kfree(prop->value);
    kfree(prop);
}

static struct property *dlpar_parse_cc_property(struct cc_workarea *ccwa)
{
    struct property *prop;
    char *name;
    char *value;

    prop = kzalloc(sizeof(*prop), GFP_KERNEL);
    if (!prop)
        return NULL;

    name = (char *)ccwa + ccwa->name_offset;
    prop->name = kstrdup(name, GFP_KERNEL);

    prop->length = ccwa->prop_length;
    value = (char *)ccwa + ccwa->prop_offset;
    prop->value = kmemdup(value, prop->length, GFP_KERNEL);
    if (!prop->value) {
        dlpar_free_cc_property(prop);
        return NULL;
    }

    return prop;
}

static struct device_node *dlpar_parse_cc_node(struct cc_workarea *ccwa)
{
    struct device_node *dn;
    char *name;

    dn = kzalloc(sizeof(*dn), GFP_KERNEL);
    if (!dn)
        return NULL;

    /* The configure connector reported name does not contain a
     * preceding '/', so we allocate a buffer large enough to
     * prepend this to the full_name.
     */
    name = (char *)ccwa + ccwa->name_offset;
    dn->full_name = kasprintf(GFP_KERNEL, "/%s", name);
    if (!dn->full_name) {
        kfree(dn);
        return NULL;
    }

    return dn;
}

static void dlpar_free_one_cc_node(struct device_node *dn)
{
    struct property *prop;

    while (dn->properties) {
        prop = dn->properties;
        dn->properties = prop->next;
        dlpar_free_cc_property(prop);
    }

    kfree(dn->full_name);
    kfree(dn);
}

void dlpar_free_cc_nodes(struct device_node *dn)
{
    if (dn->child)
        dlpar_free_cc_nodes(dn->child);

    if (dn->sibling)
        dlpar_free_cc_nodes(dn->sibling);

    dlpar_free_one_cc_node(dn);
}

#define COMPLETE    0
#define NEXT_SIBLING    1
#define NEXT_CHILD      2
#define NEXT_PROPERTY   3
#define PREV_PARENT     4
#define MORE_MEMORY     5
#define CALL_AGAIN  -2
#define ERR_CFG_USE     -9003

struct device_node *dlpar_configure_connector(u32 drc_index)
{
    struct device_node *dn;
    struct device_node *first_dn = NULL;
    struct device_node *last_dn = NULL;
    struct property *property;
    struct property *last_property = NULL;
    struct cc_workarea *ccwa;
    char *data_buf;
    int cc_token;
    int rc = -1;

    cc_token = rtas_token("ibm,configure-connector");
    if (cc_token == RTAS_UNKNOWN_SERVICE)
        return NULL;

    data_buf = kzalloc(RTAS_DATA_BUF_SIZE, GFP_KERNEL);
    if (!data_buf)
        return NULL;

    ccwa = (struct cc_workarea *)&data_buf[0];
    ccwa->drc_index = drc_index;
    ccwa->zero = 0;

    do {
        /* Since we release the rtas_data_buf lock between configure
         * connector calls we want to re-populate the rtas_data_buffer
         * with the contents of the previous call.
         */
        spin_lock(&rtas_data_buf_lock);

        memcpy(rtas_data_buf, data_buf, RTAS_DATA_BUF_SIZE);
        rc = rtas_call(cc_token, 2, 1, NULL, rtas_data_buf, NULL);
        memcpy(data_buf, rtas_data_buf, RTAS_DATA_BUF_SIZE);

        spin_unlock(&rtas_data_buf_lock);

        switch (rc) {
        case COMPLETE:
            break;

        case NEXT_SIBLING:
            dn = dlpar_parse_cc_node(ccwa);
            if (!dn)
                goto cc_error;

            dn->parent = last_dn->parent;
            last_dn->sibling = dn;
            last_dn = dn;
            break;

        case NEXT_CHILD:
            dn = dlpar_parse_cc_node(ccwa);
            if (!dn)
                goto cc_error;

            if (!first_dn)
                first_dn = dn;
            else {
                dn->parent = last_dn;
                if (last_dn)
                    last_dn->child = dn;
            }

            last_dn = dn;
            break;

        case NEXT_PROPERTY:
            property = dlpar_parse_cc_property(ccwa);
            if (!property)
                goto cc_error;

            if (!last_dn->properties)
                last_dn->properties = property;
            else
                last_property->next = property;

            last_property = property;
            break;

        case PREV_PARENT:
            last_dn = last_dn->parent;
            break;

        case CALL_AGAIN:
            break;

        case MORE_MEMORY:
        case ERR_CFG_USE:
        default:
            printk(KERN_ERR "Unexpected Error (%d) "
                   "returned from configure-connector\n", rc);
            goto cc_error;
        }
    } while (rc);

cc_error:
    kfree(data_buf);

    if (rc) {
        if (first_dn)
            dlpar_free_cc_nodes(first_dn);

        return NULL;
    }

    return first_dn;
}

static struct device_node *derive_parent(const char *path)
{
    struct device_node *parent;
    char *last_slash;

    last_slash = strrchr(path, '/');
    if (last_slash == path) {
        parent = of_find_node_by_path("/");
    } else {
        char *parent_path;
        int parent_path_len = last_slash - path + 1;
        parent_path = kmalloc(parent_path_len, GFP_KERNEL);
        if (!parent_path)
            return NULL;

        strlcpy(parent_path, path, parent_path_len);
        parent = of_find_node_by_path(parent_path);
        kfree(parent_path);
    }

    return parent;
}

int dlpar_attach_node(struct device_node *dn)
{
#ifdef CONFIG_PROC_DEVICETREE
    struct proc_dir_entry *ent;
#endif
    int rc;

    of_node_set_flag(dn, OF_DYNAMIC);
    kref_init(&dn->kref);
    dn->parent = derive_parent(dn->full_name);
    if (!dn->parent)
        return -ENOMEM;

    rc = pSeries_reconfig_notify(PSERIES_RECONFIG_ADD, dn);
    if (rc) {
        printk(KERN_ERR "Failed to add device node %s\n",
               dn->full_name);
        return rc;
    }

    of_attach_node(dn);

#ifdef CONFIG_PROC_DEVICETREE
    ent = proc_mkdir(strrchr(dn->full_name, '/') + 1, dn->parent->pde);
    if (ent)
        proc_device_tree_add_node(dn, ent);
#endif

    of_node_put(dn->parent);
    return 0;
}

int dlpar_detach_node(struct device_node *dn)
{
#ifdef CONFIG_PROC_DEVICETREE
    struct device_node *parent = dn->parent;
    struct property *prop = dn->properties;

    while (prop) {
        remove_proc_entry(prop->name, dn->pde);
        prop = prop->next;
    }

    if (dn->pde)
        remove_proc_entry(dn->pde->name, parent->pde);
#endif

    pSeries_reconfig_notify(PSERIES_RECONFIG_REMOVE, dn);
    of_detach_node(dn);
    of_node_put(dn); /* Must decrement the refcount */

    return 0;
}

#define DR_ENTITY_SENSE     9003
#define DR_ENTITY_PRESENT   1
#define DR_ENTITY_UNUSABLE  2
#define ALLOCATION_STATE    9003
#define ALLOC_UNUSABLE      0
#define ALLOC_USABLE        1
#define ISOLATION_STATE     9001
#define ISOLATE         0
#define UNISOLATE       1

int dlpar_acquire_drc(u32 drc_index)
{
    int dr_status, rc;

    rc = rtas_call(rtas_token("get-sensor-state"), 2, 2, &dr_status,
               DR_ENTITY_SENSE, drc_index);
    if (rc || dr_status != DR_ENTITY_UNUSABLE)
        return -1;

    rc = rtas_set_indicator(ALLOCATION_STATE, drc_index, ALLOC_USABLE);
    if (rc)
        return rc;

    rc = rtas_set_indicator(ISOLATION_STATE, drc_index, UNISOLATE);
    if (rc) {
        rtas_set_indicator(ALLOCATION_STATE, drc_index, ALLOC_UNUSABLE);
        return rc;
    }

    return 0;
}

int dlpar_release_drc(u32 drc_index)
{
    int dr_status, rc;

    rc = rtas_call(rtas_token("get-sensor-state"), 2, 2, &dr_status,
               DR_ENTITY_SENSE, drc_index);
    if (rc || dr_status != DR_ENTITY_PRESENT)
        return -1;

    rc = rtas_set_indicator(ISOLATION_STATE, drc_index, ISOLATE);
    if (rc)
        return rc;

    rc = rtas_set_indicator(ALLOCATION_STATE, drc_index, ALLOC_UNUSABLE);
    if (rc) {
        rtas_set_indicator(ISOLATION_STATE, drc_index, UNISOLATE);
        return rc;
    }

    return 0;
}

#ifdef CONFIG_ARCH_CPU_PROBE_RELEASE

static int dlpar_online_cpu(struct device_node *dn)
{
    int rc = 0;
    unsigned int cpu;
    int len, nthreads, i;
    const u32 *intserv;

    intserv = of_get_property(dn, "ibm,ppc-interrupt-server#s", &len);
    if (!intserv)
        return -EINVAL;

    nthreads = len / sizeof(u32);

    cpu_maps_update_begin();
    for (i = 0; i < nthreads; i++) {
        for_each_present_cpu(cpu) {
            if (get_hard_smp_processor_id(cpu) != intserv[i])
                continue;
            BUG_ON(get_cpu_current_state(cpu)
                    != CPU_STATE_OFFLINE);
            cpu_maps_update_done();
            rc = cpu_up(cpu);
            if (rc)
                goto out;
            cpu_maps_update_begin();

            break;
        }
        if (cpu == num_possible_cpus())
            printk(KERN_WARNING "Could not find cpu to online "
                   "with physical id 0x%x\n", intserv[i]);
    }
    cpu_maps_update_done();

out:
    return rc;

}

static ssize_t dlpar_cpu_probe(const char *buf, size_t count)
{
    struct device_node *dn;
    unsigned long drc_index;
    char *cpu_name;
    int rc;

    cpu_hotplug_driver_lock();
    rc = strict_strtoul(buf, 0, &drc_index);
    if (rc) {
        rc = -EINVAL;
        goto out;
    }

    dn = dlpar_configure_connector(drc_index);
    if (!dn) {
        rc = -EINVAL;
        goto out;
    }

    /* configure-connector reports cpus as living in the base
     * directory of the device tree.  CPUs actually live in the
     * cpus directory so we need to fixup the full_name.
     */
    cpu_name = kasprintf(GFP_KERNEL, "/cpus%s", dn->full_name);
    if (!cpu_name) {
        dlpar_free_cc_nodes(dn);
        rc = -ENOMEM;
        goto out;
    }

    kfree(dn->full_name);
    dn->full_name = cpu_name;

    rc = dlpar_acquire_drc(drc_index);
    if (rc) {
        dlpar_free_cc_nodes(dn);
        rc = -EINVAL;
        goto out;
    }

    rc = dlpar_attach_node(dn);
    if (rc) {
        dlpar_release_drc(drc_index);
        dlpar_free_cc_nodes(dn);
        goto out;
    }

    rc = dlpar_online_cpu(dn);
out:
    cpu_hotplug_driver_unlock();

    return rc ? rc : count;
}

static int dlpar_offline_cpu(struct device_node *dn)
{
    int rc = 0;
    unsigned int cpu;
    int len, nthreads, i;
    const u32 *intserv;

    intserv = of_get_property(dn, "ibm,ppc-interrupt-server#s", &len);
    if (!intserv)
        return -EINVAL;

    nthreads = len / sizeof(u32);

    cpu_maps_update_begin();
    for (i = 0; i < nthreads; i++) {
        for_each_present_cpu(cpu) {
            if (get_hard_smp_processor_id(cpu) != intserv[i])
                continue;

            if (get_cpu_current_state(cpu) == CPU_STATE_OFFLINE)
                break;

            if (get_cpu_current_state(cpu) == CPU_STATE_ONLINE) {
                set_preferred_offline_state(cpu, CPU_STATE_OFFLINE);
                cpu_maps_update_done();
                rc = cpu_down(cpu);
                if (rc)
                    goto out;
                cpu_maps_update_begin();
                break;

            }

            /*
             * The cpu is in CPU_STATE_INACTIVE.
             * Upgrade it's state to CPU_STATE_OFFLINE.
             */
            set_preferred_offline_state(cpu, CPU_STATE_OFFLINE);
            BUG_ON(plpar_hcall_norets(H_PROD, intserv[i])
                                != H_SUCCESS);
            __cpu_die(cpu);
            break;
        }
        if (cpu == num_possible_cpus())
            printk(KERN_WARNING "Could not find cpu to offline "
                   "with physical id 0x%x\n", intserv[i]);
    }
    cpu_maps_update_done();

out:
    return rc;

}

static ssize_t dlpar_cpu_release(const char *buf, size_t count)
{
    struct device_node *dn;
    const u32 *drc_index;
    int rc;

    dn = of_find_node_by_path(buf);
    if (!dn)
        return -EINVAL;

    drc_index = of_get_property(dn, "ibm,my-drc-index", NULL);
    if (!drc_index) {
        of_node_put(dn);
        return -EINVAL;
    }

    cpu_hotplug_driver_lock();
    rc = dlpar_offline_cpu(dn);
    if (rc) {
        of_node_put(dn);
        rc = -EINVAL;
        goto out;
    }

    rc = dlpar_release_drc(*drc_index);
    if (rc) {
        of_node_put(dn);
        goto out;
    }

    rc = dlpar_detach_node(dn);
    if (rc) {
        dlpar_acquire_drc(*drc_index);
        goto out;
    }

    of_node_put(dn);
out:
    cpu_hotplug_driver_unlock();
    return rc ? rc : count;
}

static int __init pseries_dlpar_init(void)
{
    ppc_md.cpu_probe = dlpar_cpu_probe;
    ppc_md.cpu_release = dlpar_cpu_release;

    return 0;
}
machine_device_initcall(pseries, pseries_dlpar_init);

#endif /* CONFIG_ARCH_CPU_PROBE_RELEASE */