// SPDX-License-Identifier: GPL-2.0
/*
 *    SCLP OCF communication parameters sysfs interface
 *
 *    Copyright IBM Corp. 2011
 *    Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
 */

#define pr_fmt(fmt) "sclp_ocf: " fmt

#include <linux/export.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/stat.h>
#include <linux/device.h>
#include <linux/string.h>
#include <linux/ctype.h>
#include <linux/kmod.h>
#include <linux/timer.h>
#include <linux/err.h>
#include <asm/ebcdic.h>
#include <asm/sclp.h>

#include "sclp.h"

#define OCF_LENGTH_HMC_NETWORK 8UL
#define OCF_LENGTH_CPC_NAME 8UL

static char hmc_network[OCF_LENGTH_HMC_NETWORK + 1];
static char cpc_name[OCF_LENGTH_CPC_NAME]; /* in EBCDIC */

static DEFINE_SPINLOCK(sclp_ocf_lock);
static struct work_struct sclp_ocf_change_work;

static struct kset *ocf_kset;

static void sclp_ocf_change_notify(struct work_struct *work)
{
        kobject_uevent(&ocf_kset->kobj, KOBJ_CHANGE);
}

/* Handler for OCF event. Look for the CPC image name. */
static void sclp_ocf_handler(struct evbuf_header *evbuf)
{
        struct gds_vector *v;
        struct gds_subvector *sv, *netid, *cpc;
        size_t size;

        /* Find the 0x9f00 block. */
        v = sclp_find_gds_vector(evbuf + 1, (void *) evbuf + evbuf->length,
                                 0x9f00);
        if (!v)
                return;
        /* Find the 0x9f22 block inside the 0x9f00 block. */
        v = sclp_find_gds_vector(v + 1, (void *) v + v->length, 0x9f22);
        if (!v)
                return;
        /* Find the 0x81 block inside the 0x9f22 block. */
        sv = sclp_find_gds_subvector(v + 1, (void *) v + v->length, 0x81);
        if (!sv)
                return;
        /* Find the 0x01 block inside the 0x81 block. */
        netid = sclp_find_gds_subvector(sv + 1, (void *) sv + sv->length, 1);
        /* Find the 0x02 block inside the 0x81 block. */
        cpc = sclp_find_gds_subvector(sv + 1, (void *) sv + sv->length, 2);
        /* Copy network name and cpc name. */
        spin_lock(&sclp_ocf_lock);
        if (netid) {
                size = min(OCF_LENGTH_HMC_NETWORK, (size_t) netid->length);
                memcpy(hmc_network, netid + 1, size);
                EBCASC(hmc_network, size);
                hmc_network[size] = 0;
        }
        if (cpc) {
                size = min(OCF_LENGTH_CPC_NAME, (size_t) cpc->length);
                memset(cpc_name, 0, OCF_LENGTH_CPC_NAME);
                memcpy(cpc_name, cpc + 1, size);
        }
        spin_unlock(&sclp_ocf_lock);
        schedule_work(&sclp_ocf_change_work);
}

static struct sclp_register sclp_ocf_event = {
        .receive_mask = EVTYP_OCF_MASK,
        .receiver_fn = sclp_ocf_handler,
};

void sclp_ocf_cpc_name_copy(char *dst)
{
        spin_lock_irq(&sclp_ocf_lock);
        memcpy(dst, cpc_name, OCF_LENGTH_CPC_NAME);
        spin_unlock_irq(&sclp_ocf_lock);
}
EXPORT_SYMBOL(sclp_ocf_cpc_name_copy);

static ssize_t cpc_name_show(struct kobject *kobj,
                             struct kobj_attribute *attr, char *page)
{
        char name[OCF_LENGTH_CPC_NAME + 1];

        sclp_ocf_cpc_name_copy(name);
        name[OCF_LENGTH_CPC_NAME] = 0;
        EBCASC(name, OCF_LENGTH_CPC_NAME);
        return sysfs_emit(page, "%s\n", name);
}

static struct kobj_attribute cpc_name_attr =
        __ATTR(cpc_name, 0444, cpc_name_show, NULL);

static ssize_t hmc_network_show(struct kobject *kobj,
                                struct kobj_attribute *attr, char *page)
{
        int rc;

        spin_lock_irq(&sclp_ocf_lock);
        rc = sysfs_emit(page, "%s\n", hmc_network);
        spin_unlock_irq(&sclp_ocf_lock);
        return rc;
}

static struct kobj_attribute hmc_network_attr =
        __ATTR(hmc_network, 0444, hmc_network_show, NULL);

static struct attribute *ocf_attrs[] = {
        &cpc_name_attr.attr,
        &hmc_network_attr.attr,
        NULL,
};

static const struct attribute_group ocf_attr_group = {
        .attrs = ocf_attrs,
};

static int __init ocf_init(void)
{
        int rc;

        INIT_WORK(&sclp_ocf_change_work, sclp_ocf_change_notify);
        ocf_kset = kset_create_and_add("ocf", NULL, firmware_kobj);
        if (!ocf_kset)
                return -ENOMEM;

        rc = sysfs_create_group(&ocf_kset->kobj, &ocf_attr_group);
        if (rc) {
                kset_unregister(ocf_kset);
                return rc;
        }

        return sclp_register(&sclp_ocf_event);
}

device_initcall(ocf_init);