/* SPDX-License-Identifier: BSD-3-Clause
 * Copyright (c) 2018, Microsoft Corporation.
 * All Rights Reserved.
 */

#include <string.h>
#include <unistd.h>
#include <dirent.h>
#include <fcntl.h>
#include <sys/queue.h>
#include <sys/mman.h>

#include <rte_log.h>
#include <rte_bus.h>
#include <rte_eal.h>
#include <rte_tailq.h>
#include <rte_devargs.h>
#include <rte_lcore.h>
#include <rte_malloc.h>
#include <rte_errno.h>
#include <rte_memory.h>
#include <rte_bus_vmbus.h>

#include "private.h"

extern struct rte_vmbus_bus rte_vmbus_bus;

/* map a particular resource from a file */
void *
vmbus_map_resource(void *requested_addr, int fd, off_t offset, size_t size,
                   int flags)
{
        void *mapaddr;

        /* Map the memory resource of device */
        mapaddr = mmap(requested_addr, size, PROT_READ | PROT_WRITE,
                       MAP_SHARED | flags, fd, offset);
        if (mapaddr == MAP_FAILED) {
                VMBUS_LOG(ERR,
                          "mmap(%d, %p, %zu, %ld) failed: %s",
                          fd, requested_addr, size, (long)offset,
                          strerror(errno));
        }
        return mapaddr;
}

/* unmap a particular resource */
void
vmbus_unmap_resource(void *requested_addr, size_t size)
{
        if (requested_addr == NULL)
                return;

        /* Unmap the VMBUS memory resource of device */
        if (munmap(requested_addr, size)) {
                VMBUS_LOG(ERR, "munmap(%p, 0x%lx) failed: %s",
                        requested_addr, (unsigned long)size,
                        strerror(errno));
        } else
                VMBUS_LOG(DEBUG, "  VMBUS memory unmapped at %p",
                          requested_addr);
}

/**
 * Match the VMBUS driver and device using UUID table
 *
 * @param drv
 *      VMBUS driver from which ID table would be extracted
 * @param pci_dev
 *      VMBUS device to match against the driver
 * @return
 *      true for successful match
 *      false for unsuccessful match
 */
static bool
vmbus_match(const struct rte_vmbus_driver *dr,
            const struct rte_vmbus_device *dev)
{
        const rte_uuid_t *id_table;

        for (id_table = dr->id_table; !rte_uuid_is_null(*id_table); ++id_table) {
                if (rte_uuid_compare(*id_table, dev->class_id) == 0)
                        return true;
        }

        return false;
}
/*
 * If device ID match, call the devinit() function of the driver.
 */
static int
vmbus_probe_one_driver(struct rte_vmbus_driver *dr,
                       struct rte_vmbus_device *dev)
{
        char guid[RTE_UUID_STRLEN];
        int ret;

        if (!vmbus_match(dr, dev))
                return 1;        /* not supported */

        rte_uuid_unparse(dev->device_id, guid, sizeof(guid));
        VMBUS_LOG(INFO, "VMBUS device %s on NUMA socket %i",
                  guid, dev->device.numa_node);

        /* TODO add block/allow logic */

        /* map resources for device */
        ret = rte_vmbus_map_device(dev);
        if (ret != 0)
                return ret;

        /* reference driver structure */
        dev->driver = dr;

        if (dev->device.numa_node < 0) {
                if (rte_socket_count() > 1)
                        VMBUS_LOG(INFO, "Device %s is not NUMA-aware, defaulting socket to 0",
                                        guid);
                dev->device.numa_node = 0;
        }

        /* call the driver probe() function */
        VMBUS_LOG(INFO, "  probe driver: %s", dr->driver.name);
        ret = dr->probe(dr, dev);
        if (ret) {
                dev->driver = NULL;
                rte_vmbus_unmap_device(dev);
        } else {
                dev->device.driver = &dr->driver;
        }

        return ret;
}

/*
 * If device class GUID matches, call the probe function of
 * register drivers for the vmbus device.
 * Return -1 if initialization failed,
 * and 1 if no driver found for this device.
 */
static int
vmbus_probe_all_drivers(struct rte_vmbus_device *dev)
{
        struct rte_vmbus_driver *dr;
        int rc;

        /* Check if a driver is already loaded */
        if (rte_dev_is_probed(&dev->device)) {
                VMBUS_LOG(DEBUG, "VMBUS driver already loaded");
                return 0;
        }

        FOREACH_DRIVER_ON_VMBUS(dr) {
                rc = vmbus_probe_one_driver(dr, dev);
                if (rc < 0) /* negative is an error */
                        return -1;

                if (rc > 0) /* positive driver doesn't support it */
                        continue;

                return 0;
        }
        return 1;
}

/*
 * Scan the vmbus, and call the devinit() function for
 * all registered drivers that have a matching entry in its id_table
 * for discovered devices.
 */
int
rte_vmbus_probe(void)
{
        struct rte_vmbus_device *dev;
        size_t probed = 0, failed = 0;
        char ubuf[RTE_UUID_STRLEN];

        FOREACH_DEVICE_ON_VMBUS(dev) {
                probed++;

                rte_uuid_unparse(dev->device_id, ubuf, sizeof(ubuf));

                /* TODO: add allowlist/blocklist */

                if (vmbus_probe_all_drivers(dev) < 0) {
                        VMBUS_LOG(NOTICE,
                                "Requested device %s cannot be used", ubuf);
                        rte_errno = errno;
                        failed++;
                }
        }

        return (probed && probed == failed) ? -1 : 0;
}

static int
vmbus_parse(const char *name, void *addr)
{
        rte_uuid_t guid;
        int ret;

        ret = rte_uuid_parse(name, guid);
        if (ret == 0 && addr)
                memcpy(addr, &guid, sizeof(guid));

        return ret;
}

/*
 * scan for matching device args on command line
 * example:
 *      -a 'vmbus:635a7ae3-091e-4410-ad59-667c4f8c04c3,latency=20'
 */
struct rte_devargs *
vmbus_devargs_lookup(struct rte_vmbus_device *dev)
{
        struct rte_devargs *devargs;
        rte_uuid_t addr;

        RTE_EAL_DEVARGS_FOREACH("vmbus", devargs) {
                vmbus_parse(devargs->name, &addr);

                if (rte_uuid_compare(dev->device_id, addr) == 0)
                        return devargs;
        }
        return NULL;

}

/* register vmbus driver */
void
rte_vmbus_register(struct rte_vmbus_driver *driver)
{
        VMBUS_LOG(DEBUG,
                "Registered driver %s", driver->driver.name);

        TAILQ_INSERT_TAIL(&rte_vmbus_bus.driver_list, driver, next);
        driver->bus = &rte_vmbus_bus;
}

/* unregister vmbus driver */
void
rte_vmbus_unregister(struct rte_vmbus_driver *driver)
{
        TAILQ_REMOVE(&rte_vmbus_bus.driver_list, driver, next);
        driver->bus = NULL;
}

/* Add a device to VMBUS bus */
void
vmbus_add_device(struct rte_vmbus_device *vmbus_dev)
{
        TAILQ_INSERT_TAIL(&rte_vmbus_bus.device_list, vmbus_dev, next);
}

/* Insert a device into a predefined position in VMBUS bus */
void
vmbus_insert_device(struct rte_vmbus_device *exist_vmbus_dev,
                      struct rte_vmbus_device *new_vmbus_dev)
{
        TAILQ_INSERT_BEFORE(exist_vmbus_dev, new_vmbus_dev, next);
}

/* Remove a device from VMBUS bus */
void
vmbus_remove_device(struct rte_vmbus_device *vmbus_dev)
{
        TAILQ_REMOVE(&rte_vmbus_bus.device_list, vmbus_dev, next);
}

/* VMBUS doesn't support hotplug */
static struct rte_device *
vmbus_find_device(const struct rte_device *start, rte_dev_cmp_t cmp,
                  const void *data)
{
        struct rte_vmbus_device *dev;

        FOREACH_DEVICE_ON_VMBUS(dev) {
                if (start && &dev->device == start) {
                        start = NULL;
                        continue;
                }
                if (cmp(&dev->device, data) == 0)
                        return &dev->device;
        }

        return NULL;
}


struct rte_vmbus_bus rte_vmbus_bus = {
        .bus = {
                .scan = rte_vmbus_scan,
                .probe = rte_vmbus_probe,
                .find_device = vmbus_find_device,
                .parse = vmbus_parse,
        },
        .device_list = TAILQ_HEAD_INITIALIZER(rte_vmbus_bus.device_list),
        .driver_list = TAILQ_HEAD_INITIALIZER(rte_vmbus_bus.driver_list),
};

RTE_REGISTER_BUS(vmbus, rte_vmbus_bus.bus);
RTE_LOG_REGISTER_DEFAULT(vmbus_logtype_bus, NOTICE);