// SPDX-License-Identifier: GPL-2.0
/*
 *    tape device driver for S/390 and zSeries tapes.
 *
 *  S390 and zSeries version
 *    Copyright IBM Corp. 2001
 *    Author(s): Carsten Otte <cotte@de.ibm.com>
 *               Michael Holzheu <holzheu@de.ibm.com>
 *               Tuan Ngo-Anh <ngoanh@de.ibm.com>
 *
 * PROCFS Functions
 */

#define pr_fmt(fmt) "tape: " fmt

#include <linux/module.h>
#include <linux/vmalloc.h>
#include <linux/seq_file.h>
#include <linux/proc_fs.h>

#define TAPE_DBF_AREA   tape_core_dbf

#include "tape.h"

static const char *tape_med_st_verbose[MS_SIZE] =
{
        [MS_UNKNOWN] = "UNKNOWN ",
        [MS_LOADED] = "LOADED  ",
        [MS_UNLOADED] = "UNLOADED"
};

/* our proc tapedevices entry */
static struct proc_dir_entry *tape_proc_devices;

/*
 * Show function for /proc/tapedevices
 */
static int tape_proc_show(struct seq_file *m, void *v)
{
        struct tape_device *device;
        struct tape_request *request;
        const char *str;
        unsigned long n;

        n = (unsigned long) v - 1;
        if (!n) {
                seq_printf(m, "TapeNo\tBusID      CuType/Model\t"
                        "DevType/Model\tBlkSize\tState\tOp\tMedState\n");
        }
        device = tape_find_device(n);
        if (IS_ERR(device))
                return 0;
        spin_lock_irq(get_ccwdev_lock(device->cdev));
        seq_printf(m, "%d\t", (int) n);
        seq_printf(m, "%-10.10s ", dev_name(&device->cdev->dev));
        seq_printf(m, "%04X/", device->cdev->id.cu_type);
        seq_printf(m, "%02X\t", device->cdev->id.cu_model);
        seq_printf(m, "%04X/", device->cdev->id.dev_type);
        seq_printf(m, "%02X\t\t", device->cdev->id.dev_model);
        if (device->char_data.block_size == 0)
                seq_printf(m, "auto\t");
        else
                seq_printf(m, "%i\t", device->char_data.block_size);
        if (device->tape_state >= 0 &&
            device->tape_state < TS_SIZE)
                str = tape_state_verbose[device->tape_state];
        else
                str = "UNKNOWN";
        seq_printf(m, "%s\t", str);
        if (!list_empty(&device->req_queue)) {
                request = list_entry(device->req_queue.next,
                                     struct tape_request, list);
                str = tape_op_verbose[request->op];
        } else
                str = "---";
        seq_printf(m, "%s\t", str);
        seq_printf(m, "%s\n", tape_med_st_verbose[device->medium_state]);
        spin_unlock_irq(get_ccwdev_lock(device->cdev));
        tape_put_device(device);
        return 0;
}

static void *tape_proc_start(struct seq_file *m, loff_t *pos)
{
        if (*pos >= 256 / TAPE_MINORS_PER_DEV)
                return NULL;
        return (void *)((unsigned long) *pos + 1);
}

static void *tape_proc_next(struct seq_file *m, void *v, loff_t *pos)
{
        ++*pos;
        return tape_proc_start(m, pos);
}

static void tape_proc_stop(struct seq_file *m, void *v)
{
}

static const struct seq_operations tape_proc_seq = {
        .start          = tape_proc_start,
        .next           = tape_proc_next,
        .stop           = tape_proc_stop,
        .show           = tape_proc_show,
};

/*
 * Initialize procfs stuff on startup
 */
void
tape_proc_init(void)
{
        tape_proc_devices = proc_create_seq("tapedevices", 0444, NULL,
                                            &tape_proc_seq);
}

/*
 * Cleanup all stuff registered to the procfs
 */
void
tape_proc_cleanup(void)
{
        if (tape_proc_devices != NULL)
                remove_proc_entry ("tapedevices", NULL);
}