/*
 * Remote Processor Framework
 *
 * Copyright (C) 2011 Texas Instruments, Inc.
 * Copyright (C) 2011 Google, Inc.
 *
 * Ohad Ben-Cohen <ohad@wizery.com>
 * Mark Grosen <mgrosen@ti.com>
 * Brian Swetland <swetland@google.com>
 * Fernando Guzman Lugo <fernando.lugo@ti.com>
 * Suman Anna <s-anna@ti.com>
 * Robert Tivy <rtivy@ti.com>
 * Armando Uribe De Leon <x0095078@ti.com>
 *
 * 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.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#define pr_fmt(fmt)    "%s: " fmt, __func__

#include <linux/kernel.h>
#include <linux/debugfs.h>
#include <linux/remoteproc.h>
#include <linux/device.h>
#include <linux/uaccess.h>

#include "remoteproc_internal.h"

/* remoteproc debugfs parent dir */
static struct dentry *rproc_dbg;

/*
 * Some remote processors may support dumping trace logs into a shared
 * memory buffer. We expose this trace buffer using debugfs, so users
 * can easily tell what's going on remotely.
 *
 * We will most probably improve the rproc tracing facilities later on,
 * but this kind of lightweight and simple mechanism is always good to have,
 * as it provides very early tracing with little to no dependencies at all.
 */
static ssize_t rproc_trace_read(struct file *filp, char __user *userbuf,
                                size_t count, loff_t *ppos)
{
        struct rproc_debug_trace *data = filp->private_data;
        struct rproc_mem_entry *trace = &data->trace_mem;
        void *va;
        char buf[100];
        int len;

        va = rproc_da_to_va(data->rproc, trace->da, trace->len);

        if (!va) {
                len = scnprintf(buf, sizeof(buf), "Trace %s not available\n",
                                trace->name);
                va = buf;
        } else {
                len = strnlen(va, trace->len);
        }

        return simple_read_from_buffer(userbuf, count, ppos, va, len);
}

static const struct file_operations trace_rproc_ops = {
        .read = rproc_trace_read,
        .open = simple_open,
        .llseek = generic_file_llseek,
};

/* expose the name of the remote processor via debugfs */
static ssize_t rproc_name_read(struct file *filp, char __user *userbuf,
                               size_t count, loff_t *ppos)
{
        struct rproc *rproc = filp->private_data;
        /* need room for the name, a newline and a terminating null */
        char buf[100];
        int i;

        i = scnprintf(buf, sizeof(buf), "%.98s\n", rproc->name);

        return simple_read_from_buffer(userbuf, count, ppos, buf, i);
}

static const struct file_operations rproc_name_ops = {
        .read = rproc_name_read,
        .open = simple_open,
        .llseek = generic_file_llseek,
};

/* expose recovery flag via debugfs */
static ssize_t rproc_recovery_read(struct file *filp, char __user *userbuf,
                                   size_t count, loff_t *ppos)
{
        struct rproc *rproc = filp->private_data;
        char *buf = rproc->recovery_disabled ? "disabled\n" : "enabled\n";

        return simple_read_from_buffer(userbuf, count, ppos, buf, strlen(buf));
}

/*
 * By writing to the 'recovery' debugfs entry, we control the behavior of the
 * recovery mechanism dynamically. The default value of this entry is "enabled".
 *
 * The 'recovery' debugfs entry supports these commands:
 *
 * enabled:     When enabled, the remote processor will be automatically
 *              recovered whenever it crashes. Moreover, if the remote
 *              processor crashes while recovery is disabled, it will
 *              be automatically recovered too as soon as recovery is enabled.
 *
 * disabled:    When disabled, a remote processor will remain in a crashed
 *              state if it crashes. This is useful for debugging purposes;
 *              without it, debugging a crash is substantially harder.
 *
 * recover:     This function will trigger an immediate recovery if the
 *              remote processor is in a crashed state, without changing
 *              or checking the recovery state (enabled/disabled).
 *              This is useful during debugging sessions, when one expects
 *              additional crashes to happen after enabling recovery. In this
 *              case, enabling recovery will make it hard to debug subsequent
 *              crashes, so it's recommended to keep recovery disabled, and
 *              instead use the "recover" command as needed.
 */
static ssize_t
rproc_recovery_write(struct file *filp, const char __user *user_buf,
                     size_t count, loff_t *ppos)
{
        struct rproc *rproc = filp->private_data;
        char buf[10];
        int ret;

        if (count < 1 || count > sizeof(buf))
                return -EINVAL;

        ret = copy_from_user(buf, user_buf, count);
        if (ret)
                return -EFAULT;

        /* remove end of line */
        if (buf[count - 1] == '\n')
                buf[count - 1] = '\0';

        if (!strncmp(buf, "enabled", count)) {
                rproc->recovery_disabled = false;
                /* if rproc has crashed, trigger recovery */
                if (rproc->state == RPROC_CRASHED)
                        rproc_trigger_recovery(rproc);
        } else if (!strncmp(buf, "disabled", count)) {
                rproc->recovery_disabled = true;
        } else if (!strncmp(buf, "recover", count)) {
                /* if rproc has crashed, trigger recovery */
                if (rproc->state == RPROC_CRASHED)
                        rproc_trigger_recovery(rproc);
        }

        return count;
}

static const struct file_operations rproc_recovery_ops = {
        .read = rproc_recovery_read,
        .write = rproc_recovery_write,
        .open = simple_open,
        .llseek = generic_file_llseek,
};

/* expose the crash trigger via debugfs */
static ssize_t
rproc_crash_write(struct file *filp, const char __user *user_buf,
                  size_t count, loff_t *ppos)
{
        struct rproc *rproc = filp->private_data;
        unsigned int type;
        int ret;

        ret = kstrtouint_from_user(user_buf, count, 0, &type);
        if (ret < 0)
                return ret;

        rproc_report_crash(rproc, type);

        return count;
}

static const struct file_operations rproc_crash_ops = {
        .write = rproc_crash_write,
        .open = simple_open,
        .llseek = generic_file_llseek,
};

/* Expose resource table content via debugfs */
static int rproc_rsc_table_show(struct seq_file *seq, void *p)
{
        static const char * const types[] = {"carveout", "devmem", "trace", "vdev"};
        struct rproc *rproc = seq->private;
        struct resource_table *table = rproc->table_ptr;
        struct fw_rsc_carveout *c;
        struct fw_rsc_devmem *d;
        struct fw_rsc_trace *t;
        struct fw_rsc_vdev *v;
        int i, j;

        if (!table) {
                seq_puts(seq, "No resource table found\n");
                return 0;
        }

        for (i = 0; i < table->num; i++) {
                int offset = table->offset[i];
                struct fw_rsc_hdr *hdr = (void *)table + offset;
                void *rsc = (void *)hdr + sizeof(*hdr);

                switch (hdr->type) {
                case RSC_CARVEOUT:
                        c = rsc;
                        seq_printf(seq, "Entry %d is of type %s\n", i, types[hdr->type]);
                        seq_printf(seq, "  Device Address 0x%x\n", c->da);
                        seq_printf(seq, "  Physical Address 0x%x\n", c->pa);
                        seq_printf(seq, "  Length 0x%x Bytes\n", c->len);
                        seq_printf(seq, "  Flags 0x%x\n", c->flags);
                        seq_printf(seq, "  Reserved (should be zero) [%d]\n", c->reserved);
                        seq_printf(seq, "  Name %s\n\n", c->name);
                        break;
                case RSC_DEVMEM:
                        d = rsc;
                        seq_printf(seq, "Entry %d is of type %s\n", i, types[hdr->type]);
                        seq_printf(seq, "  Device Address 0x%x\n", d->da);
                        seq_printf(seq, "  Physical Address 0x%x\n", d->pa);
                        seq_printf(seq, "  Length 0x%x Bytes\n", d->len);
                        seq_printf(seq, "  Flags 0x%x\n", d->flags);
                        seq_printf(seq, "  Reserved (should be zero) [%d]\n", d->reserved);
                        seq_printf(seq, "  Name %s\n\n", d->name);
                        break;
                case RSC_TRACE:
                        t = rsc;
                        seq_printf(seq, "Entry %d is of type %s\n", i, types[hdr->type]);
                        seq_printf(seq, "  Device Address 0x%x\n", t->da);
                        seq_printf(seq, "  Length 0x%x Bytes\n", t->len);
                        seq_printf(seq, "  Reserved (should be zero) [%d]\n", t->reserved);
                        seq_printf(seq, "  Name %s\n\n", t->name);
                        break;
                case RSC_VDEV:
                        v = rsc;
                        seq_printf(seq, "Entry %d is of type %s\n", i, types[hdr->type]);

                        seq_printf(seq, "  ID %d\n", v->id);
                        seq_printf(seq, "  Notify ID %d\n", v->notifyid);
                        seq_printf(seq, "  Device features 0x%x\n", v->dfeatures);
                        seq_printf(seq, "  Guest features 0x%x\n", v->gfeatures);
                        seq_printf(seq, "  Config length 0x%x\n", v->config_len);
                        seq_printf(seq, "  Status 0x%x\n", v->status);
                        seq_printf(seq, "  Number of vrings %d\n", v->num_of_vrings);
                        seq_printf(seq, "  Reserved (should be zero) [%d][%d]\n\n",
                                   v->reserved[0], v->reserved[1]);

                        for (j = 0; j < v->num_of_vrings; j++) {
                                seq_printf(seq, "  Vring %d\n", j);
                                seq_printf(seq, "    Device Address 0x%x\n", v->vring[j].da);
                                seq_printf(seq, "    Alignment %d\n", v->vring[j].align);
                                seq_printf(seq, "    Number of buffers %d\n", v->vring[j].num);
                                seq_printf(seq, "    Notify ID %d\n", v->vring[j].notifyid);
                                seq_printf(seq, "    Physical Address 0x%x\n\n",
                                           v->vring[j].pa);
                        }
                        break;
                default:
                        seq_printf(seq, "Unknown resource type found: %d [hdr: %pK]\n",
                                   hdr->type, hdr);
                        break;
                }
        }

        return 0;
}

static int rproc_rsc_table_open(struct inode *inode, struct file *file)
{
        return single_open(file, rproc_rsc_table_show, inode->i_private);
}

static const struct file_operations rproc_rsc_table_ops = {
        .open           = rproc_rsc_table_open,
        .read           = seq_read,
        .llseek         = seq_lseek,
        .release        = single_release,
};

/* Expose carveout content via debugfs */
static int rproc_carveouts_show(struct seq_file *seq, void *p)
{
        struct rproc *rproc = seq->private;
        struct rproc_mem_entry *carveout;

        list_for_each_entry(carveout, &rproc->carveouts, node) {
                seq_puts(seq, "Carveout memory entry:\n");
                seq_printf(seq, "\tName: %s\n", carveout->name);
                seq_printf(seq, "\tVirtual address: %pK\n", carveout->va);
                seq_printf(seq, "\tDMA address: %pad\n", &carveout->dma);
                seq_printf(seq, "\tDevice address: 0x%x\n", carveout->da);
                seq_printf(seq, "\tLength: 0x%x Bytes\n\n", carveout->len);
        }

        return 0;
}

static int rproc_carveouts_open(struct inode *inode, struct file *file)
{
        return single_open(file, rproc_carveouts_show, inode->i_private);
}

static const struct file_operations rproc_carveouts_ops = {
        .open           = rproc_carveouts_open,
        .read           = seq_read,
        .llseek         = seq_lseek,
        .release        = single_release,
};

void rproc_remove_trace_file(struct dentry *tfile)
{
        debugfs_remove(tfile);
}

struct dentry *rproc_create_trace_file(const char *name, struct rproc *rproc,
                                       struct rproc_debug_trace *trace)
{
        struct dentry *tfile;

        tfile = debugfs_create_file(name, 0400, rproc->dbg_dir, trace,
                                    &trace_rproc_ops);
        if (!tfile) {
                dev_err(&rproc->dev, "failed to create debugfs trace entry\n");
                return NULL;
        }

        return tfile;
}

void rproc_delete_debug_dir(struct rproc *rproc)
{
        if (!rproc->dbg_dir)
                return;

        debugfs_remove_recursive(rproc->dbg_dir);
}

void rproc_create_debug_dir(struct rproc *rproc)
{
        struct device *dev = &rproc->dev;

        if (!rproc_dbg)
                return;

        rproc->dbg_dir = debugfs_create_dir(dev_name(dev), rproc_dbg);
        if (!rproc->dbg_dir)
                return;

        debugfs_create_file("name", 0400, rproc->dbg_dir,
                            rproc, &rproc_name_ops);
        debugfs_create_file("recovery", 0400, rproc->dbg_dir,
                            rproc, &rproc_recovery_ops);
        debugfs_create_file("crash", 0200, rproc->dbg_dir,
                            rproc, &rproc_crash_ops);
        debugfs_create_file("resource_table", 0400, rproc->dbg_dir,
                            rproc, &rproc_rsc_table_ops);
        debugfs_create_file("carveout_memories", 0400, rproc->dbg_dir,
                            rproc, &rproc_carveouts_ops);
}

void __init rproc_init_debugfs(void)
{
        if (debugfs_initialized()) {
                rproc_dbg = debugfs_create_dir(KBUILD_MODNAME, NULL);
                if (!rproc_dbg)
                        pr_err("can't create debugfs dir\n");
        }
}

void __exit rproc_exit_debugfs(void)
{
        debugfs_remove(rproc_dbg);
}