/*
 * proc.c - procfs support for Protocol family CAN core module
 *
 * Copyright (c) 2002-2007 Volkswagen Group Electronic Research
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of Volkswagen nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * Alternatively, provided that this notice is retained in full, this
 * software may be distributed under the terms of the GNU General
 * Public License ("GPL") version 2, in which case the provisions of the
 * GPL apply INSTEAD OF those given above.
 *
 * The provided data structures and external interfaces from this code
 * are not restricted to be used by modules with a GPL compatible license.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
 * DAMAGE.
 *
 * Send feedback to <socketcan-users@lists.berlios.de>
 *
 */

#include <linux/module.h>
#include <linux/proc_fs.h>
#include <linux/list.h>
#include <linux/rcupdate.h>
#include <linux/can/core.h>

#include "af_can.h"

/*
 * proc filenames for the PF_CAN core
 */

#define CAN_PROC_VERSION     "version"
#define CAN_PROC_STATS       "stats"
#define CAN_PROC_RESET_STATS "reset_stats"
#define CAN_PROC_RCVLIST_ALL "rcvlist_all"
#define CAN_PROC_RCVLIST_FIL "rcvlist_fil"
#define CAN_PROC_RCVLIST_INV "rcvlist_inv"
#define CAN_PROC_RCVLIST_SFF "rcvlist_sff"
#define CAN_PROC_RCVLIST_EFF "rcvlist_eff"
#define CAN_PROC_RCVLIST_ERR "rcvlist_err"

static struct proc_dir_entry *can_dir;
static struct proc_dir_entry *pde_version;
static struct proc_dir_entry *pde_stats;
static struct proc_dir_entry *pde_reset_stats;
static struct proc_dir_entry *pde_rcvlist_all;
static struct proc_dir_entry *pde_rcvlist_fil;
static struct proc_dir_entry *pde_rcvlist_inv;
static struct proc_dir_entry *pde_rcvlist_sff;
static struct proc_dir_entry *pde_rcvlist_eff;
static struct proc_dir_entry *pde_rcvlist_err;

static int user_reset;

static const char rx_list_name[][8] = {
        [RX_ERR] = "rx_err",
        [RX_ALL] = "rx_all",
        [RX_FIL] = "rx_fil",
        [RX_INV] = "rx_inv",
        [RX_EFF] = "rx_eff",
};

/*
 * af_can statistics stuff
 */

static void can_init_stats(void)
{
        /*
         * This memset function is called from a timer context (when
         * can_stattimer is active which is the default) OR in a process
         * context (reading the proc_fs when can_stattimer is disabled).
         */
        memset(&can_stats, 0, sizeof(can_stats));
        can_stats.jiffies_init = jiffies;

        can_pstats.stats_reset++;

        if (user_reset) {
                user_reset = 0;
                can_pstats.user_reset++;
        }
}

static unsigned long calc_rate(unsigned long oldjif, unsigned long newjif,
                               unsigned long count)
{
        unsigned long rate;

        if (oldjif == newjif)
                return 0;

        /* see can_stat_update() - this should NEVER happen! */
        if (count > (ULONG_MAX / HZ)) {
                printk(KERN_ERR "can: calc_rate: count exceeded! %ld\n",
                       count);
                return 99999999;
        }

        rate = (count * HZ) / (newjif - oldjif);

        return rate;
}

void can_stat_update(unsigned long data)
{
        unsigned long j = jiffies; /* snapshot */

        /* restart counting in timer context on user request */
        if (user_reset)
                can_init_stats();

        /* restart counting on jiffies overflow */
        if (j < can_stats.jiffies_init)
                can_init_stats();

        /* prevent overflow in calc_rate() */
        if (can_stats.rx_frames > (ULONG_MAX / HZ))
                can_init_stats();

        /* prevent overflow in calc_rate() */
        if (can_stats.tx_frames > (ULONG_MAX / HZ))
                can_init_stats();

        /* matches overflow - very improbable */
        if (can_stats.matches > (ULONG_MAX / 100))
                can_init_stats();

        /* calc total values */
        if (can_stats.rx_frames)
                can_stats.total_rx_match_ratio = (can_stats.matches * 100) /
                        can_stats.rx_frames;

        can_stats.total_tx_rate = calc_rate(can_stats.jiffies_init, j,
                                            can_stats.tx_frames);
        can_stats.total_rx_rate = calc_rate(can_stats.jiffies_init, j,
                                            can_stats.rx_frames);

        /* calc current values */
        if (can_stats.rx_frames_delta)
                can_stats.current_rx_match_ratio =
                        (can_stats.matches_delta * 100) /
                        can_stats.rx_frames_delta;

        can_stats.current_tx_rate = calc_rate(0, HZ, can_stats.tx_frames_delta);
        can_stats.current_rx_rate = calc_rate(0, HZ, can_stats.rx_frames_delta);

        /* check / update maximum values */
        if (can_stats.max_tx_rate < can_stats.current_tx_rate)
                can_stats.max_tx_rate = can_stats.current_tx_rate;

        if (can_stats.max_rx_rate < can_stats.current_rx_rate)
                can_stats.max_rx_rate = can_stats.current_rx_rate;

        if (can_stats.max_rx_match_ratio < can_stats.current_rx_match_ratio)
                can_stats.max_rx_match_ratio = can_stats.current_rx_match_ratio;

        /* clear values for 'current rate' calculation */
        can_stats.tx_frames_delta = 0;
        can_stats.rx_frames_delta = 0;
        can_stats.matches_delta   = 0;

        /* restart timer (one second) */
        mod_timer(&can_stattimer, round_jiffies(jiffies + HZ));
}

/*
 * proc read functions
 *
 * From known use-cases we expect about 10 entries in a receive list to be
 * printed in the proc_fs. So PAGE_SIZE is definitely enough space here.
 *
 */

static void can_print_rcvlist(struct seq_file *m, struct hlist_head *rx_list,
                              struct net_device *dev)
{
        struct receiver *r;
        struct hlist_node *n;

        rcu_read_lock();
        hlist_for_each_entry_rcu(r, n, rx_list, list) {
                char *fmt = (r->can_id & CAN_EFF_FLAG)?
                        "   %-5s  %08X  %08x  %08x  %08x  %8ld  %s\n" :
                        "   %-5s     %03X    %08x  %08lx  %08lx  %8ld  %s\n";

                seq_printf(m, fmt, DNAME(dev), r->can_id, r->mask,
                                (unsigned long)r->func, (unsigned long)r->data,
                                r->matches, r->ident);
        }
        rcu_read_unlock();
}

static void can_print_recv_banner(struct seq_file *m)
{
        /*
         *                  can1.  00000000  00000000  00000000
         *                 .......          0  tp20
         */
        seq_puts(m, "  device   can_id   can_mask  function"
                        "  userdata   matches  ident\n");
}

static int can_stats_proc_show(struct seq_file *m, void *v)
{
        seq_putc(m, '\n');
        seq_printf(m, " %8ld transmitted frames (TXF)\n", can_stats.tx_frames);
        seq_printf(m, " %8ld received frames (RXF)\n", can_stats.rx_frames);
        seq_printf(m, " %8ld matched frames (RXMF)\n", can_stats.matches);

        seq_putc(m, '\n');

        if (can_stattimer.function == can_stat_update) {
                seq_printf(m, " %8ld %% total match ratio (RXMR)\n",
                                can_stats.total_rx_match_ratio);

                seq_printf(m, " %8ld frames/s total tx rate (TXR)\n",
                                can_stats.total_tx_rate);
                seq_printf(m, " %8ld frames/s total rx rate (RXR)\n",
                                can_stats.total_rx_rate);

                seq_putc(m, '\n');

                seq_printf(m, " %8ld %% current match ratio (CRXMR)\n",
                                can_stats.current_rx_match_ratio);

                seq_printf(m, " %8ld frames/s current tx rate (CTXR)\n",
                                can_stats.current_tx_rate);
                seq_printf(m, " %8ld frames/s current rx rate (CRXR)\n",
                                can_stats.current_rx_rate);

                seq_putc(m, '\n');

                seq_printf(m, " %8ld %% max match ratio (MRXMR)\n",
                                can_stats.max_rx_match_ratio);

                seq_printf(m, " %8ld frames/s max tx rate (MTXR)\n",
                                can_stats.max_tx_rate);
                seq_printf(m, " %8ld frames/s max rx rate (MRXR)\n",
                                can_stats.max_rx_rate);

                seq_putc(m, '\n');
        }

        seq_printf(m, " %8ld current receive list entries (CRCV)\n",
                        can_pstats.rcv_entries);
        seq_printf(m, " %8ld maximum receive list entries (MRCV)\n",
                        can_pstats.rcv_entries_max);

        if (can_pstats.stats_reset)
                seq_printf(m, "\n %8ld statistic resets (STR)\n",
                                can_pstats.stats_reset);

        if (can_pstats.user_reset)
                seq_printf(m, " %8ld user statistic resets (USTR)\n",
                                can_pstats.user_reset);

        seq_putc(m, '\n');
        return 0;
}

static int can_stats_proc_open(struct inode *inode, struct file *file)
{
        return single_open(file, can_stats_proc_show, NULL);
}

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

static int can_reset_stats_proc_show(struct seq_file *m, void *v)
{
        user_reset = 1;

        if (can_stattimer.function == can_stat_update) {
                seq_printf(m, "Scheduled statistic reset #%ld.\n",
                                can_pstats.stats_reset + 1);

        } else {
                if (can_stats.jiffies_init != jiffies)
                        can_init_stats();

                seq_printf(m, "Performed statistic reset #%ld.\n",
                                can_pstats.stats_reset);
        }
        return 0;
}

static int can_reset_stats_proc_open(struct inode *inode, struct file *file)
{
        return single_open(file, can_reset_stats_proc_show, NULL);
}

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

static int can_version_proc_show(struct seq_file *m, void *v)
{
        seq_printf(m, "%s\n", CAN_VERSION_STRING);
        return 0;
}

static int can_version_proc_open(struct inode *inode, struct file *file)
{
        return single_open(file, can_version_proc_show, NULL);
}

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

static int can_rcvlist_proc_show(struct seq_file *m, void *v)
{
        /* double cast to prevent GCC warning */
        int idx = (int)(long)m->private;
        struct dev_rcv_lists *d;
        struct hlist_node *n;

        seq_printf(m, "\nreceive list '%s':\n", rx_list_name[idx]);

        rcu_read_lock();
        hlist_for_each_entry_rcu(d, n, &can_rx_dev_list, list) {

                if (!hlist_empty(&d->rx[idx])) {
                        can_print_recv_banner(m);
                        can_print_rcvlist(m, &d->rx[idx], d->dev);
                } else
                        seq_printf(m, "  (%s: no entry)\n", DNAME(d->dev));
        }
        rcu_read_unlock();

        seq_putc(m, '\n');
        return 0;
}

static int can_rcvlist_proc_open(struct inode *inode, struct file *file)
{
        return single_open(file, can_rcvlist_proc_show, PDE(inode)->data);
}

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

static int can_rcvlist_sff_proc_show(struct seq_file *m, void *v)
{
        struct dev_rcv_lists *d;
        struct hlist_node *n;

        /* RX_SFF */
        seq_puts(m, "\nreceive list 'rx_sff':\n");

        rcu_read_lock();
        hlist_for_each_entry_rcu(d, n, &can_rx_dev_list, list) {
                int i, all_empty = 1;
                /* check wether at least one list is non-empty */
                for (i = 0; i < 0x800; i++)
                        if (!hlist_empty(&d->rx_sff[i])) {
                                all_empty = 0;
                                break;
                        }

                if (!all_empty) {
                        can_print_recv_banner(m);
                        for (i = 0; i < 0x800; i++) {
                                if (!hlist_empty(&d->rx_sff[i]))
                                        can_print_rcvlist(m, &d->rx_sff[i],
                                                          d->dev);
                        }
                } else
                        seq_printf(m, "  (%s: no entry)\n", DNAME(d->dev));
        }
        rcu_read_unlock();

        seq_putc(m, '\n');
        return 0;
}

static int can_rcvlist_sff_proc_open(struct inode *inode, struct file *file)
{
        return single_open(file, can_rcvlist_sff_proc_show, NULL);
}

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

/*
 * proc utility functions
 */

static void can_remove_proc_readentry(const char *name)
{
        if (can_dir)
                remove_proc_entry(name, can_dir);
}

/*
 * can_init_proc - create main CAN proc directory and procfs entries
 */
void can_init_proc(void)
{
        /* create /proc/net/can directory */
        can_dir = proc_mkdir("can", init_net.proc_net);

        if (!can_dir) {
                printk(KERN_INFO "can: failed to create /proc/net/can . "
                       "CONFIG_PROC_FS missing?\n");
                return;
        }

        /* own procfs entries from the AF_CAN core */
        pde_version     = proc_create(CAN_PROC_VERSION, 0644, can_dir,
                                      &can_version_proc_fops);
        pde_stats       = proc_create(CAN_PROC_STATS, 0644, can_dir,
                                      &can_stats_proc_fops);
        pde_reset_stats = proc_create(CAN_PROC_RESET_STATS, 0644, can_dir,
                                      &can_reset_stats_proc_fops);
        pde_rcvlist_err = proc_create_data(CAN_PROC_RCVLIST_ERR, 0644, can_dir,
                                           &can_rcvlist_proc_fops, (void *)RX_ERR);
        pde_rcvlist_all = proc_create_data(CAN_PROC_RCVLIST_ALL, 0644, can_dir,
                                           &can_rcvlist_proc_fops, (void *)RX_ALL);
        pde_rcvlist_fil = proc_create_data(CAN_PROC_RCVLIST_FIL, 0644, can_dir,
                                           &can_rcvlist_proc_fops, (void *)RX_FIL);
        pde_rcvlist_inv = proc_create_data(CAN_PROC_RCVLIST_INV, 0644, can_dir,
                                           &can_rcvlist_proc_fops, (void *)RX_INV);
        pde_rcvlist_eff = proc_create_data(CAN_PROC_RCVLIST_EFF, 0644, can_dir,
                                           &can_rcvlist_proc_fops, (void *)RX_EFF);
        pde_rcvlist_sff = proc_create(CAN_PROC_RCVLIST_SFF, 0644, can_dir,
                                      &can_rcvlist_sff_proc_fops);
}

/*
 * can_remove_proc - remove procfs entries and main CAN proc directory
 */
void can_remove_proc(void)
{
        if (pde_version)
                can_remove_proc_readentry(CAN_PROC_VERSION);

        if (pde_stats)
                can_remove_proc_readentry(CAN_PROC_STATS);

        if (pde_reset_stats)
                can_remove_proc_readentry(CAN_PROC_RESET_STATS);

        if (pde_rcvlist_err)
                can_remove_proc_readentry(CAN_PROC_RCVLIST_ERR);

        if (pde_rcvlist_all)
                can_remove_proc_readentry(CAN_PROC_RCVLIST_ALL);

        if (pde_rcvlist_fil)
                can_remove_proc_readentry(CAN_PROC_RCVLIST_FIL);

        if (pde_rcvlist_inv)
                can_remove_proc_readentry(CAN_PROC_RCVLIST_INV);

        if (pde_rcvlist_eff)
                can_remove_proc_readentry(CAN_PROC_RCVLIST_EFF);

        if (pde_rcvlist_sff)
                can_remove_proc_readentry(CAN_PROC_RCVLIST_SFF);

        if (can_dir)
                proc_net_remove(&init_net, "can");
}