/*
 * Copyright 2014 Cisco Systems, Inc.  All rights reserved.
 *
 * This program is free software; you may redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; version 2 of the License.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

#include <linux/module.h>
#include <linux/errno.h>
#include <linux/debugfs.h>

#include "snic.h"

/*
 * snic_debugfs_init - Initialize debugfs for snic debug logging
 *
 * Description:
 * When Debugfs is configured this routine sets up fnic debugfs
 * filesystem. If not already created. this routine will crate the
 * fnic directory and statistics directory for trace buffer and
 * stats logging
 */

int
snic_debugfs_init(void)
{
        int rc = -1;
        struct dentry *de = NULL;

        de = debugfs_create_dir("snic", NULL);
        if (!de) {
                SNIC_DBG("Cannot create debugfs root\n");

                return rc;
        }
        snic_glob->trc_root = de;

        de = debugfs_create_dir("statistics", snic_glob->trc_root);
        if (!de) {
                SNIC_DBG("Cannot create Statistics directory\n");

                return rc;
        }
        snic_glob->stats_root = de;

        rc = 0;

        return rc;
} /* end of snic_debugfs_init */

/*
 * snic_debugfs_term - Tear down debugfs intrastructure
 *
 * Description:
 * When Debufs is configured this routine removes debugfs file system
 * elements that are specific to snic
 */
void
snic_debugfs_term(void)
{
        debugfs_remove(snic_glob->stats_root);
        snic_glob->stats_root = NULL;

        debugfs_remove(snic_glob->trc_root);
        snic_glob->trc_root = NULL;
}

/*
 * snic_reset_stats_open - Open the reset_stats file
 */
static int
snic_reset_stats_open(struct inode *inode, struct file *filp)
{
        SNIC_BUG_ON(!inode->i_private);
        filp->private_data = inode->i_private;

        return 0;
}

/*
 * snic_reset_stats_read - Read a reset_stats debugfs file
 * @filp: The file pointer to read from.
 * @ubuf: The buffer tocopy the data to.
 * @cnt: The number of bytes to read.
 * @ppos: The position in the file to start reading frm.
 *
 * Description:
 * This routine reads value of variable reset_stats
 * and stores into local @buf. It will start reading file @ppos and
 * copy up to @cnt of data to @ubuf from @buf.
 *
 * Returns:
 * This function returns the amount of data that was read.
 */
static ssize_t
snic_reset_stats_read(struct file *filp,
                      char __user *ubuf,
                      size_t cnt,
                      loff_t *ppos)
{
        struct snic *snic = (struct snic *) filp->private_data;
        char buf[64];
        int len;

        len = sprintf(buf, "%u\n", snic->reset_stats);

        return simple_read_from_buffer(ubuf, cnt, ppos, buf, len);
}

/*
 * snic_reset_stats_write - Write to reset_stats debugfs file
 * @filp: The file pointer to write from
 * @ubuf: The buffer to copy the data from.
 * @cnt: The number of bytes to write.
 * @ppos: The position in the file to start writing to.
 *
 * Description:
 * This routine writes data from user buffer @ubuf to buffer @buf and
 * resets cumulative stats of snic.
 *
 * Returns:
 * This function returns the amount of data that was written.
 */
static ssize_t
snic_reset_stats_write(struct file *filp,
                       const char __user *ubuf,
                       size_t cnt,
                       loff_t *ppos)
{
        struct snic *snic = (struct snic *) filp->private_data;
        struct snic_stats *stats = &snic->s_stats;
        u64 *io_stats_p = (u64 *) &stats->io;
        u64 *fw_stats_p = (u64 *) &stats->fw;
        char buf[64];
        unsigned long val;
        int ret;

        if (cnt >= sizeof(buf))
                return -EINVAL;

        if (copy_from_user(&buf, ubuf, cnt))
                return -EFAULT;

        buf[cnt] = '\0';

        ret = kstrtoul(buf, 10, &val);
        if (ret < 0)
                return ret;

        snic->reset_stats = val;

        if (snic->reset_stats) {
                /* Skip variable is used to avoid descrepancies to Num IOs
                 * and IO Completions stats. Skip incrementing No IO Compls
                 * for pending active IOs after reset_stats
                 */
                atomic64_set(&snic->io_cmpl_skip,
                             atomic64_read(&stats->io.active));
                memset(&stats->abts, 0, sizeof(struct snic_abort_stats));
                memset(&stats->reset, 0, sizeof(struct snic_reset_stats));
                memset(&stats->misc, 0, sizeof(struct snic_misc_stats));
                memset(io_stats_p+1,
                        0,
                        sizeof(struct snic_io_stats) - sizeof(u64));
                memset(fw_stats_p+1,
                        0,
                        sizeof(struct snic_fw_stats) - sizeof(u64));
        }

        (*ppos)++;

        SNIC_HOST_INFO(snic->shost, "Reset Op: Driver statistics.\n");

        return cnt;
}

static int
snic_reset_stats_release(struct inode *inode, struct file *filp)
{
        filp->private_data = NULL;

        return 0;
}

/*
 * snic_stats_show - Formats and prints per host specific driver stats.
 */
static int
snic_stats_show(struct seq_file *sfp, void *data)
{
        struct snic *snic = (struct snic *) sfp->private;
        struct snic_stats *stats = &snic->s_stats;
        struct timespec last_isr_tms, last_ack_tms;
        u64 maxio_tm;
        int i;

        /* Dump IO Stats */
        seq_printf(sfp,
                   "------------------------------------------\n"
                   "\t\t IO Statistics\n"
                   "------------------------------------------\n");

        maxio_tm = (u64) atomic64_read(&stats->io.max_time);
        seq_printf(sfp,
                   "Active IOs                  : %lld\n"
                   "Max Active IOs              : %lld\n"
                   "Total IOs                   : %lld\n"
                   "IOs Completed               : %lld\n"
                   "IOs Failed                  : %lld\n"
                   "IOs Not Found               : %lld\n"
                   "Memory Alloc Failures       : %lld\n"
                   "REQs Null                   : %lld\n"
                   "SCSI Cmd Pointers Null      : %lld\n"
                   "Max SGL for any IO          : %lld\n"
                   "Max IO Size                 : %lld Sectors\n"
                   "Max Queuing Time            : %lld\n"
                   "Max Completion Time         : %lld\n"
                   "Max IO Process Time(FW)     : %lld (%u msec)\n",
                   (u64) atomic64_read(&stats->io.active),
                   (u64) atomic64_read(&stats->io.max_active),
                   (u64) atomic64_read(&stats->io.num_ios),
                   (u64) atomic64_read(&stats->io.compl),
                   (u64) atomic64_read(&stats->io.fail),
                   (u64) atomic64_read(&stats->io.io_not_found),
                   (u64) atomic64_read(&stats->io.alloc_fail),
                   (u64) atomic64_read(&stats->io.req_null),
                   (u64) atomic64_read(&stats->io.sc_null),
                   (u64) atomic64_read(&stats->io.max_sgl),
                   (u64) atomic64_read(&stats->io.max_io_sz),
                   (u64) atomic64_read(&stats->io.max_qtime),
                   (u64) atomic64_read(&stats->io.max_cmpl_time),
                   maxio_tm,
                   jiffies_to_msecs(maxio_tm));

        seq_puts(sfp, "\nSGL Counters\n");

        for (i = 0; i < SNIC_MAX_SG_DESC_CNT; i++) {
                seq_printf(sfp,
                           "%10lld ",
                           (u64) atomic64_read(&stats->io.sgl_cnt[i]));

                if ((i + 1) % 8 == 0)
                        seq_puts(sfp, "\n");
        }

        /* Dump Abort Stats */
        seq_printf(sfp,
                   "\n-------------------------------------------\n"
                   "\t\t Abort Statistics\n"
                   "---------------------------------------------\n");

        seq_printf(sfp,
                   "Aborts                      : %lld\n"
                   "Aborts Fail                 : %lld\n"
                   "Aborts Driver Timeout       : %lld\n"
                   "Abort FW Timeout            : %lld\n"
                   "Abort IO NOT Found          : %lld\n",
                   (u64) atomic64_read(&stats->abts.num),
                   (u64) atomic64_read(&stats->abts.fail),
                   (u64) atomic64_read(&stats->abts.drv_tmo),
                   (u64) atomic64_read(&stats->abts.fw_tmo),
                   (u64) atomic64_read(&stats->abts.io_not_found));

        /* Dump Reset Stats */
        seq_printf(sfp,
                   "\n-------------------------------------------\n"
                   "\t\t Reset Statistics\n"
                   "---------------------------------------------\n");

        seq_printf(sfp,
                   "HBA Resets                  : %lld\n"
                   "HBA Reset Cmpls             : %lld\n"
                   "HBA Reset Fail              : %lld\n",
                   (u64) atomic64_read(&stats->reset.hba_resets),
                   (u64) atomic64_read(&stats->reset.hba_reset_cmpl),
                   (u64) atomic64_read(&stats->reset.hba_reset_fail));

        /* Dump Firmware Stats */
        seq_printf(sfp,
                   "\n-------------------------------------------\n"
                   "\t\t Firmware Statistics\n"
                   "---------------------------------------------\n");

        seq_printf(sfp,
                "Active FW Requests             : %lld\n"
                "Max FW Requests                : %lld\n"
                "FW Out Of Resource Errs        : %lld\n"
                "FW IO Errors                   : %lld\n"
                "FW SCSI Errors                 : %lld\n",
                (u64) atomic64_read(&stats->fw.actv_reqs),
                (u64) atomic64_read(&stats->fw.max_actv_reqs),
                (u64) atomic64_read(&stats->fw.out_of_res),
                (u64) atomic64_read(&stats->fw.io_errs),
                (u64) atomic64_read(&stats->fw.scsi_errs));


        /* Dump Miscellenous Stats */
        seq_printf(sfp,
                   "\n---------------------------------------------\n"
                   "\t\t Other Statistics\n"
                   "\n---------------------------------------------\n");

        jiffies_to_timespec(stats->misc.last_isr_time, &last_isr_tms);
        jiffies_to_timespec(stats->misc.last_ack_time, &last_ack_tms);

        seq_printf(sfp,
                   "Last ISR Time               : %llu (%8lu.%8lu)\n"
                   "Last Ack Time               : %llu (%8lu.%8lu)\n"
                   "ISRs                        : %llu\n"
                   "Max CQ Entries              : %lld\n"
                   "Data Count Mismatch         : %lld\n"
                   "IOs w/ Timeout Status       : %lld\n"
                   "IOs w/ Aborted Status       : %lld\n"
                   "IOs w/ SGL Invalid Stat     : %lld\n"
                   "WQ Desc Alloc Fail          : %lld\n"
                   "Queue Full                  : %lld\n"
                   "Target Not Ready            : %lld\n",
                   (u64) stats->misc.last_isr_time,
                   last_isr_tms.tv_sec, last_isr_tms.tv_nsec,
                   (u64)stats->misc.last_ack_time,
                   last_ack_tms.tv_sec, last_ack_tms.tv_nsec,
                   (u64) atomic64_read(&stats->misc.isr_cnt),
                   (u64) atomic64_read(&stats->misc.max_cq_ents),
                   (u64) atomic64_read(&stats->misc.data_cnt_mismat),
                   (u64) atomic64_read(&stats->misc.io_tmo),
                   (u64) atomic64_read(&stats->misc.io_aborted),
                   (u64) atomic64_read(&stats->misc.sgl_inval),
                   (u64) atomic64_read(&stats->misc.wq_alloc_fail),
                   (u64) atomic64_read(&stats->misc.qfull),
                   (u64) atomic64_read(&stats->misc.tgt_not_rdy));

        return 0;
}

/*
 * snic_stats_open - Open the stats file for specific host
 *
 * Description:
 * This routine opens a debugfs file stats of specific host
 */
static int
snic_stats_open(struct inode *inode, struct file *filp)
{
        return single_open(filp, snic_stats_show, inode->i_private);
}

static const struct file_operations snic_stats_fops = {
        .owner  = THIS_MODULE,
        .open   = snic_stats_open,
        .read   = seq_read,
        .llseek = seq_lseek,
        .release = single_release,
};

static const struct file_operations snic_reset_stats_fops = {
        .owner = THIS_MODULE,
        .open = snic_reset_stats_open,
        .read = snic_reset_stats_read,
        .write = snic_reset_stats_write,
        .release = snic_reset_stats_release,
};

/*
 * snic_stats_init - Initialize stats struct and create stats file
 * per snic
 *
 * Description:
 * When debugfs is cofigured this routine sets up the stats file per snic
 * It will create file stats and reset_stats under statistics/host# directory
 * to log per snic stats
 */
int
snic_stats_debugfs_init(struct snic *snic)
{
        int rc = -1;
        char name[16];
        struct dentry *de = NULL;

        snprintf(name, sizeof(name), "host%d", snic->shost->host_no);
        if (!snic_glob->stats_root) {
                SNIC_DBG("snic_stats root doesn't exist\n");

                return rc;
        }

        de = debugfs_create_dir(name, snic_glob->stats_root);
        if (!de) {
                SNIC_DBG("Cannot create host directory\n");

                return rc;
        }
        snic->stats_host = de;

        de = debugfs_create_file("stats",
                                S_IFREG|S_IRUGO,
                                snic->stats_host,
                                snic,
                                &snic_stats_fops);
        if (!de) {
                SNIC_DBG("Cannot create host's stats file\n");

                return rc;
        }
        snic->stats_file = de;

        de = debugfs_create_file("reset_stats",
                                S_IFREG|S_IRUGO|S_IWUSR,
                                snic->stats_host,
                                snic,
                                &snic_reset_stats_fops);

        if (!de) {
                SNIC_DBG("Cannot create host's reset_stats file\n");

                return rc;
        }
        snic->reset_stats_file = de;
        rc = 0;

        return rc;
} /* end of snic_stats_debugfs_init */

/*
 * snic_stats_debugfs_remove - Tear down debugfs infrastructure of stats
 *
 * Description:
 * When Debufs is configured this routine removes debugfs file system
 * elements that are specific to to snic stats
 */
void
snic_stats_debugfs_remove(struct snic *snic)
{
        debugfs_remove(snic->stats_file);
        snic->stats_file = NULL;

        debugfs_remove(snic->reset_stats_file);
        snic->reset_stats_file = NULL;

        debugfs_remove(snic->stats_host);
        snic->stats_host = NULL;
}

/* Trace Facility related API */
static void *
snic_trc_seq_start(struct seq_file *sfp, loff_t *pos)
{
        return &snic_glob->trc;
}

static void *
snic_trc_seq_next(struct seq_file *sfp, void *data, loff_t *pos)
{
        return NULL;
}

static void
snic_trc_seq_stop(struct seq_file *sfp, void *data)
{
}

#define SNIC_TRC_PBLEN  256
static int
snic_trc_seq_show(struct seq_file *sfp, void *data)
{
        char buf[SNIC_TRC_PBLEN];

        if (snic_get_trc_data(buf, SNIC_TRC_PBLEN) > 0)
                seq_printf(sfp, "%s\n", buf);

        return 0;
}

static const struct seq_operations snic_trc_seq_ops = {
        .start  = snic_trc_seq_start,
        .next   = snic_trc_seq_next,
        .stop   = snic_trc_seq_stop,
        .show   = snic_trc_seq_show,
};

static int
snic_trc_open(struct inode *inode, struct file *filp)
{
        return seq_open(filp, &snic_trc_seq_ops);
}

static const struct file_operations snic_trc_fops = {
        .owner  = THIS_MODULE,
        .open   = snic_trc_open,
        .read   = seq_read,
        .llseek = seq_lseek,
        .release = seq_release,
};

/*
 * snic_trc_debugfs_init : creates trace/tracing_enable files for trace
 * under debugfs
 */
int
snic_trc_debugfs_init(void)
{
        struct dentry *de = NULL;
        int ret = -1;

        if (!snic_glob->trc_root) {
                SNIC_ERR("Debugfs root directory for snic doesn't exist.\n");

                return ret;
        }

        de = debugfs_create_bool("tracing_enable",
                                 S_IFREG | S_IRUGO | S_IWUSR,
                                 snic_glob->trc_root,
                                 &snic_glob->trc.enable);

        if (!de) {
                SNIC_ERR("Can't create trace_enable file.\n");

                return ret;
        }
        snic_glob->trc.trc_enable = de;

        de = debugfs_create_file("trace",
                                 S_IFREG | S_IRUGO | S_IWUSR,
                                 snic_glob->trc_root,
                                 NULL,
                                 &snic_trc_fops);

        if (!de) {
                SNIC_ERR("Cann't create trace file.\n");

                return ret;
        }
        snic_glob->trc.trc_file = de;
        ret = 0;

        return ret;
} /* end of snic_trc_debugfs_init */

/*
 * snic_trc_debugfs_term : cleans up the files created for trace under debugfs
 */
void
snic_trc_debugfs_term(void)
{
        debugfs_remove(snic_glob->trc.trc_file);
        snic_glob->trc.trc_file = NULL;

        debugfs_remove(snic_glob->trc.trc_enable);
        snic_glob->trc.trc_enable = NULL;
}