/*
 * Copyright © 2017 Intel Corporation
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice (including the next
 * paragraph) shall be included in all copies or substantial portions of the
 * Software.
 *
 * 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 <sys/types.h>
#include <fcntl.h>
#include <limits.h>

#include <sys/stat.h>
#ifdef __linux__
#include <sys/sysmacros.h>
#endif
#include "igt.h"
#include "igt_device.h"
#include "igt_sysfs.h"

int __igt_device_set_master(int fd)
{
	int err;

	err = 0;
	if (drmIoctl(fd, DRM_IOCTL_SET_MASTER, NULL)) {
		err = -errno;
		igt_assume(err);
	}

	errno = 0;
	return err;
}

static void show_clients(int fd)
{
	__igt_debugfs_dump(fd, "clients", IGT_LOG_WARN);
}

/**
 * igt_device_set_master: Set the device fd to be DRM master
 * @fd: the device
 *
 * Tell the kernel to make this device fd become DRM master or skip the test.
 */
void igt_device_set_master(int fd)
{
	if (__igt_device_set_master(fd)) {
		show_clients(fd);
		igt_require_f(__igt_device_set_master(fd) == 0,
			      "Can't become DRM master, "
			      "please check if no other DRM client is running.\n");
	}
}

int __igt_device_drop_master(int fd)
{
	int err;

	err = 0;
	if (drmIoctl(fd, DRM_IOCTL_DROP_MASTER, NULL)) {
		err = -errno;
		igt_assume(err);
	}

	errno = 0;
	return err;
}

/**
 * igt_device_drop_master: Drop DRM master
 * @fd: the device
 *
 * Tell the kernel we no longer want this device fd to be the DRM master;
 * asserting that we lose the privilege. Return if we are master already.
 */
void igt_device_drop_master(int fd)
{
	/* Check if we are master before dropping */
	if (__igt_device_set_master(fd))
		return;

	if (__igt_device_drop_master(fd)) {
		show_clients(fd);
		igt_assert_f(__igt_device_drop_master(fd) == 0,
			      "Failed to drop DRM master.\n");
	}
}

/**
 * igt_device_get_card_index:
 * @fd: the device
 *
 * Returns:
 * Index (N) of /dev/dri/cardN or /dev/dri/renderDN corresponding with fd.
 *
 */
int igt_device_get_card_index(int fd)
{
	struct stat st;

	igt_fail_on(fstat(fd, &st) || !S_ISCHR(st.st_mode));

	return minor(st.st_rdev);
}

#define IGT_DEV_PATH_LEN 80

static bool igt_device_is_pci(int fd)
{
	char path[IGT_DEV_PATH_LEN];
	char *subsystem;
	int sysfs;
	int len;

	sysfs = igt_sysfs_open(fd);
	if (sysfs == -1)
		return false;

	len = readlinkat(sysfs, "device/subsystem", path, sizeof(path) - 1);
	close(sysfs);
	if (len == -1)
		return false;
	path[len] = '\0';

	subsystem = strrchr(path, '/');
	if (!subsystem)
		return false;

	return strcmp(subsystem, "/pci") == 0;
}

struct igt_pci_addr {
	unsigned int domain;
	unsigned int bus;
	unsigned int device;
	unsigned int function;
};

static int igt_device_get_pci_addr(int fd, unsigned int vf_id, struct igt_pci_addr *pci)
{
	char link[20], path[IGT_DEV_PATH_LEN];
	char *buf;
	int sysfs;
	int len;

	if (!igt_device_is_pci(fd))
		return -ENODEV;

	if (vf_id)
		len = snprintf(link, sizeof(link), "device/virtfn%u", vf_id - 1);
	else
		len = snprintf(link, sizeof(link), "device");
	if (igt_warn_on_f(len >= sizeof(link),
			  "IGT bug: insufficient buffer space for rendering PCI device link name\n"))
		return -ENOSPC;
	else if (igt_debug_on_f(len < 0, "unexpected failure from snprintf()\n"))
		return len;

	sysfs = igt_sysfs_open(fd);
	if (sysfs == -1)
		return -ENOENT;

	len = readlinkat(sysfs, link, path, sizeof(path) - 1);
	close(sysfs);
	if (len == -1)
		return -ENOENT;
	path[len] = '\0';

	buf = strrchr(path, '/');
	if (!buf)
		return -ENOENT;

	if (sscanf(buf, "/%4x:%2x:%2x.%2x",
		   &pci->domain, &pci->bus,
		   &pci->device, &pci->function) != 4) {
		igt_warn("Unable to extract PCI device address from '%s'\n", buf);
		return -ENOENT;
	}

	return 0;
}

/**
 * __igt_device_get_pci_device:
 *
 * @fd: DRM device file descriptor
 * @vf_id: PCI virtual function number (0 if native or PF itself)
 *
 * Looks up a PCI interface of a DRM device or a VF PCI device of the DRM PF using libpciaccess.
 *
 * Returns:
 * The pci_device, NULL on any failures.
 */
struct pci_device *__igt_device_get_pci_device(int fd, unsigned int vf_id)
{
	struct igt_pci_addr pci_addr;
	struct pci_device *pci_dev;

	if (igt_device_get_pci_addr(fd, vf_id, &pci_addr)) {
		igt_warn("Unable to find device PCI address\n");
		return NULL;
	}

	if (igt_pci_system_init()) {
		igt_warn("Couldn't initialize PCI system\n");
		return NULL;
	}

	pci_dev = pci_device_find_by_slot(pci_addr.domain,
					  pci_addr.bus,
					  pci_addr.device,
					  pci_addr.function);
	if (!pci_dev) {
		igt_warn("Couldn't find PCI device %04x:%02x:%02x:%02x\n",
			 pci_addr.domain, pci_addr.bus,
			 pci_addr.device, pci_addr.function);
		return NULL;
	}

	if (pci_device_probe(pci_dev)) {
		igt_warn("Couldn't probe PCI device\n");
		return NULL;
	}

	return pci_dev;
}

/**
 * igt_device_get_pci_device:
 *
 * @fd: the device
 *
 * Looks up the main graphics pci device using libpciaccess.
 *
 * Returns:
 * The pci_device, skips the test on any failures.
 */
struct pci_device *igt_device_get_pci_device(int fd)
{
	struct pci_device *pci_dev;

	pci_dev = __igt_device_get_pci_device(fd, 0);
	igt_require(pci_dev);

	return pci_dev;
}

/**
 * igt_device_get_pci_root_port:
 * @fd: the device.
 *
 * Looks up the graphics pci device root port using libpciaccess.
 *
 * Returns:
 * The root port pci_device.
 */
struct pci_device *
igt_device_get_pci_root_port(int fd)
{
	struct pci_device *pci_dev, *prev;

	pci_dev = __igt_device_get_pci_device(fd, 0);
	igt_require(pci_dev);

	while (pci_dev) {
		prev = pci_dev;
		pci_dev = pci_device_get_parent_bridge(pci_dev);
	}

	igt_debug("Root Port PCI device %04x:%02x:%02x.%01x\n",
		  prev->domain, prev->bus, prev->dev, prev->func);

	return prev;
}

/**
 * igt_device_get_pci_slot_name:
 * @fd: the device.
 * @pci_slot_name: pci slot name
 *
 * Looks up the graphics pci device using libpciaccess
 * and gets the slot name
 */
void igt_device_get_pci_slot_name(int fd, char *pci_slot_name)
{
	struct pci_device *pci_dev;

	pci_dev = __igt_device_get_pci_device(fd, 0);
	igt_require(pci_dev);

	igt_assert(pci_slot_name);
	snprintf(pci_slot_name, NAME_MAX, "%04x:%02x:%02x.%01x",
		 pci_dev->domain, pci_dev->bus, pci_dev->dev, pci_dev->func);
}