/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2006 IronPort Systems
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/ctype.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/mount.h>
#include <sys/sbuf.h>
#include <sys/smp.h>
#include <sys/bus.h>
#include <sys/pciio.h>

#include <dev/pci/pcivar.h>
#include <dev/pci/pcireg.h>

#include <compat/linux/linux_util.h>
#include <fs/pseudofs/pseudofs.h>

#include <compat/linsysfs/linsysfs.h>

MALLOC_DEFINE(M_LINSYSFS, "linsysfs", "Linsysfs structures");

struct scsi_host_queue {
        TAILQ_ENTRY(scsi_host_queue) scsi_host_next;
        char *path;
        char *name;
};

TAILQ_HEAD(,scsi_host_queue) scsi_host_q;

static int host_number = 0;

static int
atoi(const char *str)
{
        return (int)strtol(str, (char **)NULL, 10);
}

/*
 * Filler function for proc_name
 */
static int
linsysfs_scsiname(PFS_FILL_ARGS)
{
        struct scsi_host_queue *scsi_host;
        int index;

        if (strncmp(pn->pn_parent->pn_name, "host", 4) == 0) {
                index = atoi(&pn->pn_parent->pn_name[4]);
        } else {
                sbuf_printf(sb, "unknown\n");
                return (0);
        }
        TAILQ_FOREACH(scsi_host, &scsi_host_q, scsi_host_next) {
                if (index-- == 0) {
                        sbuf_printf(sb, "%s\n", scsi_host->name);
                        return (0);
                }
        }
        sbuf_printf(sb, "unknown\n");
        return (0);
}

/*
 * Filler function for device sym-link
 */
static int
linsysfs_link_scsi_host(PFS_FILL_ARGS)
{
        struct scsi_host_queue *scsi_host;
        int index;

        if (strncmp(pn->pn_parent->pn_name, "host", 4) == 0) {
                index = atoi(&pn->pn_parent->pn_name[4]);
        } else {
                sbuf_printf(sb, "unknown\n");
                return (0);
        }
        TAILQ_FOREACH(scsi_host, &scsi_host_q, scsi_host_next) {
                if (index-- == 0) {
                        sbuf_printf(sb, "../../../devices%s", scsi_host->path);
                        return(0);
                }
        }
        sbuf_printf(sb, "unknown\n");
        return (0);
}

static int
linsysfs_fill_data(PFS_FILL_ARGS)
{
        sbuf_printf(sb, "%s", (char *)pn->pn_data);
        return (0);
}

static int
linsysfs_fill_vendor(PFS_FILL_ARGS)
{
        sbuf_printf(sb, "0x%04x\n", pci_get_vendor((device_t)pn->pn_data));
        return (0);
}

static int
linsysfs_fill_device(PFS_FILL_ARGS)
{
        sbuf_printf(sb, "0x%04x\n", pci_get_device((device_t)pn->pn_data));
        return (0);
}

static int
linsysfs_fill_subvendor(PFS_FILL_ARGS)
{
        sbuf_printf(sb, "0x%04x\n", pci_get_subvendor((device_t)pn->pn_data));
        return (0);
}

static int
linsysfs_fill_subdevice(PFS_FILL_ARGS)
{
        sbuf_printf(sb, "0x%04x\n", pci_get_subdevice((device_t)pn->pn_data));
        return (0);
}

static int
linsysfs_fill_revid(PFS_FILL_ARGS)
{
        sbuf_printf(sb, "0x%x\n", pci_get_revid((device_t)pn->pn_data));
        return (0);
}

static int
linsysfs_fill_config(PFS_FILL_ARGS)
{
        uint8_t config[48];
        device_t dev;
        uint32_t reg;

        dev = (device_t)pn->pn_data;
        bzero(config, sizeof(config));
        reg = pci_get_vendor(dev);
        config[0] = reg;
        config[1] = reg >> 8;
        reg = pci_get_device(dev);
        config[2] = reg;
        config[3] = reg >> 8;
        reg = pci_get_revid(dev);
        config[8] = reg;
        reg = pci_get_subvendor(dev);
        config[44] = reg;
        config[45] = reg >> 8;
        reg = pci_get_subdevice(dev);
        config[46] = reg;
        config[47] = reg >> 8;
        sbuf_bcat(sb, config, sizeof(config));
        return (0);
}

/*
 * Filler function for PCI uevent file
 */
static int
linsysfs_fill_uevent_pci(PFS_FILL_ARGS)
{
        device_t dev;

        dev = (device_t)pn->pn_data;
        sbuf_printf(sb, "DRIVER=%s\nPCI_CLASS=%X\nPCI_ID=%04X:%04X\n"
            "PCI_SUBSYS_ID=%04X:%04X\nPCI_SLOT_NAME=%04d:%02x:%02x.%x\n",
            linux_driver_get_name_dev(dev), pci_get_class(dev),
            pci_get_vendor(dev), pci_get_device(dev), pci_get_subvendor(dev),
            pci_get_subdevice(dev), pci_get_domain(dev), pci_get_bus(dev),
            pci_get_slot(dev), pci_get_function(dev));
        return (0);
}

/*
 * Filler function for drm uevent file
 */
static int
linsysfs_fill_uevent_drm(PFS_FILL_ARGS)
{
        device_t dev;
        int unit;

        dev = (device_t)pn->pn_data;
        unit = device_get_unit(dev);
        sbuf_printf(sb,
            "MAJOR=226\nMINOR=%d\nDEVNAME=dri/card%d\nDEVTYPE=dri_minor\n",
            unit, unit);
        return (0);
}

static char *
get_full_pfs_path(struct pfs_node *cur)
{
        char *temp, *path;

        temp = malloc(MAXPATHLEN, M_TEMP, M_WAITOK);
        path = malloc(MAXPATHLEN, M_TEMP, M_WAITOK);
        path[0] = '\0';

        do {
                snprintf(temp, MAXPATHLEN, "%s/%s", cur->pn_name, path);
                strlcpy(path, temp, MAXPATHLEN);
                cur = cur->pn_parent;
        } while (cur->pn_parent != NULL);

        path[strlen(path) - 1] = '\0'; /* remove extra slash */
        free(temp, M_TEMP);
        return (path);
}

/*
 * Filler function for symlink from drm char device to PCI device
 */
static int
linsysfs_fill_vgapci(PFS_FILL_ARGS)
{
        char *path;

        path = get_full_pfs_path((struct pfs_node*)pn->pn_data);
        sbuf_printf(sb, "../../../%s", path);
        free(path, M_TEMP);
        return (0);
}

#undef PCI_DEV
#define PCI_DEV "pci"
#define DRMN_DEV "drmn"
static int
linsysfs_run_bus(device_t dev, struct pfs_node *dir, struct pfs_node *scsi,
    struct pfs_node *chardev, struct pfs_node *drm, char *path, char *prefix)
{
        struct scsi_host_queue *scsi_host;
        struct pfs_node *sub_dir, *cur_file;
        int i, nchildren, error;
        device_t *children, parent;
        devclass_t devclass;
        const char *name = NULL;
        struct pci_devinfo *dinfo;
        char *device, *host, *new_path, *devname;

        children = NULL;
        device = host = NULL;
        new_path = path;
        devname = malloc(16, M_TEMP, M_WAITOK);

        parent = device_get_parent(dev);
        if (parent) {
                devclass = device_get_devclass(parent);
                if (devclass != NULL)
                        name = devclass_get_name(devclass);
                if (name && strcmp(name, PCI_DEV) == 0) {
                        dinfo = device_get_ivars(dev);
                        if (dinfo) {
                                device = malloc(MAXPATHLEN, M_TEMP, M_WAITOK);
                                new_path = malloc(MAXPATHLEN, M_TEMP,
                                    M_WAITOK);
                                new_path[0] = '\000';
                                strcpy(new_path, path);
                                host = malloc(MAXPATHLEN, M_TEMP, M_WAITOK);
                                device[0] = '\000';
                                sprintf(device, "%s:%02x:%02x.%x",
                                    prefix,
                                    dinfo->cfg.bus,
                                    dinfo->cfg.slot,
                                    dinfo->cfg.func);
                                strcat(new_path, "/");
                                strcat(new_path, device);
                                error = pfs_create_dir(dir, &dir, device,
                                    NULL, NULL, NULL, 0);
                                if (error != 0)
                                        goto out;
                                pfs_create_dir(dir, &dir, device, NULL, NULL,
                                    NULL, 0);
                                pfs_create_file(dir, &cur_file, "vendor",
                                    &linsysfs_fill_vendor, NULL, NULL, NULL,
                                    PFS_RD);
                                cur_file->pn_data = (void*)dev;
                                pfs_create_file(dir, &cur_file, "device",
                                    &linsysfs_fill_device, NULL, NULL, NULL,
                                    PFS_RD);
                                cur_file->pn_data = (void*)dev;
                                pfs_create_file(dir, &cur_file,
                                    "subsystem_vendor",
                                    &linsysfs_fill_subvendor, NULL, NULL, NULL,
                                    PFS_RD);
                                cur_file->pn_data = (void*)dev;
                                pfs_create_file(dir, &cur_file,
                                    "subsystem_device",
                                    &linsysfs_fill_subdevice, NULL, NULL, NULL,
                                    PFS_RD);
                                cur_file->pn_data = (void*)dev;
                                pfs_create_file(dir, &cur_file, "revision",
                                    &linsysfs_fill_revid, NULL, NULL, NULL,
                                    PFS_RD);
                                cur_file->pn_data = (void*)dev;
                                pfs_create_file(dir, &cur_file, "config",
                                    &linsysfs_fill_config, NULL, NULL, NULL,
                                    PFS_RD);
                                cur_file->pn_data = (void*)dev;
                                pfs_create_file(dir, &cur_file, "uevent",
                                    &linsysfs_fill_uevent_pci, NULL, NULL, NULL,
                                    PFS_RD);
                                cur_file->pn_data = (void*)dev;
                                pfs_create_link(dir, &cur_file, "subsystem",
                                    &linsysfs_fill_data, NULL, NULL, NULL, 0);
                                /* libdrm just checks that the link ends in "/pci" */
                                cur_file->pn_data = "/sys/bus/pci";

                                if (dinfo->cfg.baseclass == PCIC_STORAGE) {
                                        /* DJA only make this if needed */
                                        sprintf(host, "host%d", host_number++);
                                        strcat(new_path, "/");
                                        strcat(new_path, host);
                                        pfs_create_dir(dir, NULL, host, NULL,
                                            NULL, NULL, 0);
                                        scsi_host = malloc(sizeof(
                                            struct scsi_host_queue),
                                            M_DEVBUF, M_WAITOK);
                                        scsi_host->path = malloc(
                                            strlen(new_path) + 1,
                                            M_DEVBUF, M_WAITOK);
                                        scsi_host->path[0] = '\000';
                                        bcopy(new_path, scsi_host->path,
                                            strlen(new_path) + 1);
                                        scsi_host->name = "unknown";

                                        pfs_create_dir(scsi, &sub_dir, host,
                                            NULL, NULL, NULL, 0);
                                        pfs_create_link(sub_dir, NULL, "device",
                                            &linsysfs_link_scsi_host, NULL,
                                            NULL, NULL, 0);
                                        pfs_create_file(sub_dir, NULL,
                                            "proc_name", &linsysfs_scsiname,
                                            NULL, NULL, NULL, PFS_RD);
                                        scsi_host->name
                                            = linux_driver_get_name_dev(dev);
                                        TAILQ_INSERT_TAIL(&scsi_host_q,
                                            scsi_host, scsi_host_next);
                                }
                        }
                }

                devclass = device_get_devclass(dev);
                if (devclass != NULL)
                        name = devclass_get_name(devclass);
                else
                        name = NULL;
                if (name != NULL && strcmp(name, DRMN_DEV) == 0 &&
                    device_get_unit(dev) >= 0) {
                        dinfo = device_get_ivars(parent);
                        if (dinfo != NULL && dinfo->cfg.baseclass == PCIC_DISPLAY) {
                                pfs_create_dir(dir, NULL, "drm", NULL, NULL,
                                    NULL, 0);
                                sprintf(devname, "226:%d",
                                    device_get_unit(dev));
                                pfs_create_dir(chardev, &sub_dir, devname, NULL,
                                    NULL, NULL, 0);
                                pfs_create_link(sub_dir, &cur_file, "device",
                                    &linsysfs_fill_vgapci, NULL, NULL, NULL,
                                    PFS_RD);
                                cur_file->pn_data = (void*)dir;
                                pfs_create_file(sub_dir, &cur_file, "uevent",
                                    &linsysfs_fill_uevent_drm, NULL, NULL, NULL,
                                    PFS_RD);
                                cur_file->pn_data = (void*)dev;
                                sprintf(devname, "card%d",
                                    device_get_unit(dev));
                                pfs_create_dir(drm, &sub_dir, devname, NULL,
                                    NULL, NULL, 0);
                                pfs_create_link(sub_dir, &cur_file, "device",
                                    &linsysfs_fill_vgapci, NULL, NULL, NULL,
                                    PFS_RD);
                                cur_file->pn_data = (void*)dir;
                        }
                }
        }

        error = device_get_children(dev, &children, &nchildren);
        if (error == 0) {
                for (i = 0; i < nchildren; i++) {
                        if (children[i]) {
                                error = linsysfs_run_bus(children[i], dir, scsi,
                                    chardev, drm, new_path, prefix);
                                if (error != 0) {
                                        printf(
                                            "linsysfs_run_bus: %s omitted from sysfs tree, error %d\n",
                                            device_get_nameunit(children[i]),
                                            error);
                                }
                        }
                }

                /*
                 * We override the error to avoid cascading failures; the
                 * innermost device that failed in a tree is probably the most
                 * significant one for diagnostics, its parents would be noise.
                 */
                error = 0;
        }

out:
        free(host, M_TEMP);
        free(device, M_TEMP);
        if (children != NULL)
                free(children, M_TEMP);
        if (new_path != path)
                free(new_path, M_TEMP);
        free(devname, M_TEMP);

        return (error);
}

/*
 * Filler function for sys/devices/system/cpu/{online,possible,present}
 */
static int
linsysfs_cpuonline(PFS_FILL_ARGS)
{

        sbuf_printf(sb, "%d-%d\n", CPU_FIRST(), mp_maxid);
        return (0);
}

/*
 * Filler function for sys/devices/system/cpu/cpuX/online
 */
static int
linsysfs_cpuxonline(PFS_FILL_ARGS)
{

        sbuf_printf(sb, "1\n");
        return (0);
}

static void
linsysfs_listcpus(struct pfs_node *dir)
{
        struct pfs_node *cpu;
        char *name;
        int i, count, len;

        len = 1;
        count = mp_maxcpus;
        while (count > 10) {
                count /= 10;
                len++;
        }
        len += sizeof("cpu");
        name = malloc(len, M_TEMP, M_WAITOK);

        for (i = 0; i < mp_ncpus; ++i) {
                /* /sys/devices/system/cpu/cpuX */
                sprintf(name, "cpu%d", i);
                pfs_create_dir(dir, &cpu, name, NULL, NULL, NULL, 0);

                pfs_create_file(cpu, NULL, "online", &linsysfs_cpuxonline, NULL,
                    NULL, NULL, PFS_RD);
        }
        free(name, M_TEMP);
}

/*
 * Constructor
 */
static int
linsysfs_init(PFS_INIT_ARGS)
{
        struct pfs_node *root;
        struct pfs_node *class;
        struct pfs_node *dir, *sys, *cpu;
        struct pfs_node *drm;
        struct pfs_node *pci;
        struct pfs_node *scsi;
        struct pfs_node *devdir, *chardev;
        struct pfs_node *kernel;
        devclass_t devclass;
        device_t dev;

        TAILQ_INIT(&scsi_host_q);

        root = pi->pi_root;

        /* /sys/bus/... */
        pfs_create_dir(root, &dir, "bus", NULL, NULL, NULL, 0);

        /* /sys/class/... */
        pfs_create_dir(root, &class, "class", NULL, NULL, NULL, 0);
        pfs_create_dir(class, &scsi, "scsi_host", NULL, NULL, NULL, 0);
        pfs_create_dir(class, &drm, "drm", NULL, NULL, NULL, 0);
        pfs_create_dir(class, NULL, "power_supply", NULL, NULL, NULL, 0);

        /* /sys/class/net/.. */
        pfs_create_dir(class, &net, "net", NULL, NULL, NULL, 0);

        /* /sys/dev/... */
        pfs_create_dir(root, &devdir, "dev", NULL, NULL, NULL, 0);
        pfs_create_dir(devdir, &chardev, "char", NULL, NULL, NULL, 0);

        /* /sys/devices/... */
        pfs_create_dir(root, &dir, "devices", NULL, NULL, NULL, 0);
        pfs_create_dir(dir, &pci, "pci0000:00", NULL, NULL, NULL, 0);

        devclass = devclass_find("root");
        if (devclass == NULL) {
                return (0);
        }

        /*
         * This assumes that the root node is unlikely to error out in
         * linsysfs_run_bus, which may or may not be true.
         */
        dev = devclass_get_device(devclass, 0);
        linsysfs_run_bus(dev, pci, scsi, chardev, drm, "/pci0000:00", "0000");

        /* /sys/devices/system */
        pfs_create_dir(dir, &sys, "system", NULL, NULL, NULL, 0);

        /* /sys/devices/system/cpu */
        pfs_create_dir(sys, &cpu, "cpu", NULL, NULL, NULL, 0);

        pfs_create_file(cpu, NULL, "online", &linsysfs_cpuonline, NULL, NULL,
            NULL, PFS_RD);
        pfs_create_file(cpu, NULL, "possible", &linsysfs_cpuonline, NULL, NULL,
            NULL, PFS_RD);
        pfs_create_file(cpu, NULL, "present", &linsysfs_cpuonline, NULL, NULL,
            NULL, PFS_RD);

        linsysfs_listcpus(cpu);

        /* /sys/kernel */
        pfs_create_dir(root, &kernel, "kernel", NULL, NULL, NULL, 0);
        /* /sys/kernel/debug, mountpoint for lindebugfs. */
        pfs_create_dir(kernel, NULL, "debug", NULL, NULL, NULL, 0);

        linsysfs_net_init();

        return (0);
}

/*
 * Destructor
 */
static int
linsysfs_uninit(PFS_INIT_ARGS)
{
        struct scsi_host_queue *scsi_host, *scsi_host_tmp;

        TAILQ_FOREACH_SAFE(scsi_host, &scsi_host_q, scsi_host_next,
            scsi_host_tmp) {
                TAILQ_REMOVE(&scsi_host_q, scsi_host, scsi_host_next);
                free(scsi_host->path, M_TEMP);
                free(scsi_host, M_TEMP);
        }

        linsysfs_net_uninit();

        return (0);
}

PSEUDOFS(linsysfs, 1, VFCF_JAIL);
#if defined(__aarch64__) || defined(__amd64__)
MODULE_DEPEND(linsysfs, linux_common, 1, 1, 1);
#else
MODULE_DEPEND(linsysfs, linux, 1, 1, 1);
#endif