/*-
 * GPL LICENSE SUMMARY
 *
 *   Copyright(c) 2010-2014 Intel Corporation. All rights reserved.
 *
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of version 2 of the GNU General Public License 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.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program; if not, write to the Free Software
 *   Foundation, Inc., 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
 *   The full GNU General Public License is included in this distribution
 *   in the file called LICENSE.GPL.
 *
 *   Contact Information:
 *   Intel Corporation
 */

#include <linux/version.h>
#include <linux/module.h>
#include <linux/miscdevice.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/pci.h>
#include <linux/kthread.h>
#include <linux/rwsem.h>
#include <linux/nsproxy.h>
#include <net/net_namespace.h>
#include <net/netns/generic.h>

#include <exec-env/rte_kni_common.h>

#include "compat.h"
#include "kni_dev.h"

MODULE_LICENSE("Dual BSD/GPL");
MODULE_AUTHOR("Intel Corporation");
MODULE_DESCRIPTION("Kernel Module for managing kni devices");

#define KNI_RX_LOOP_NUM 1000

#define KNI_MAX_DEVICES 32

extern void kni_net_rx(struct kni_dev *kni);
extern void kni_net_init(struct net_device *dev);
extern void kni_net_config_lo_mode(char *lo_str);
extern void kni_net_poll_resp(struct kni_dev *kni);
extern void kni_set_ethtool_ops(struct net_device *netdev);

extern int ixgbe_kni_probe(struct pci_dev *pdev, struct net_device **lad_dev);
extern void ixgbe_kni_remove(struct pci_dev *pdev);
extern int igb_kni_probe(struct pci_dev *pdev, struct net_device **lad_dev);
extern void igb_kni_remove(struct pci_dev *pdev);

static int kni_open(struct inode *inode, struct file *file);
static int kni_release(struct inode *inode, struct file *file);
static int kni_ioctl(struct inode *inode, unsigned int ioctl_num,
					unsigned long ioctl_param);
static int kni_compat_ioctl(struct inode *inode, unsigned int ioctl_num,
						unsigned long ioctl_param);
static int kni_dev_remove(struct kni_dev *dev);

static int __init kni_parse_kthread_mode(void);

/* KNI processing for single kernel thread mode */
static int kni_thread_single(void *unused);
/* KNI processing for multiple kernel thread mode */
static int kni_thread_multiple(void *param);

static struct file_operations kni_fops = {
	.owner = THIS_MODULE,
	.open = kni_open,
	.release = kni_release,
	.unlocked_ioctl = (void *)kni_ioctl,
	.compat_ioctl = (void *)kni_compat_ioctl,
};

static struct miscdevice kni_misc = {
	.minor = MISC_DYNAMIC_MINOR,
	.name = KNI_DEVICE,
	.fops = &kni_fops,
};

/* loopback mode */
static char *lo_mode = NULL;

/* Kernel thread mode */
static char *kthread_mode = NULL;
static unsigned multiple_kthread_on = 0;

#define KNI_DEV_IN_USE_BIT_NUM 0 /* Bit number for device in use */

static int kni_net_id;

struct kni_net {
	unsigned long device_in_use; /* device in use flag */
	struct task_struct *kni_kthread;
	struct rw_semaphore kni_list_lock;
	struct list_head kni_list_head;
};

static int __net_init kni_init_net(struct net *net)
{
#ifdef HAVE_SIMPLIFIED_PERNET_OPERATIONS
	struct kni_net *knet = net_generic(net, kni_net_id);
#else
	struct kni_net *knet;
	int ret;

	knet = kmalloc(sizeof(struct kni_net), GFP_KERNEL);
	if (!knet) {
		ret = -ENOMEM;
		return ret;
	}
#endif

	/* Clear the bit of device in use */
	clear_bit(KNI_DEV_IN_USE_BIT_NUM, &knet->device_in_use);

	init_rwsem(&knet->kni_list_lock);
	INIT_LIST_HEAD(&knet->kni_list_head);

#ifdef HAVE_SIMPLIFIED_PERNET_OPERATIONS
	return 0;
#else
	ret = net_assign_generic(net, kni_net_id, knet);
	if (ret < 0)
		kfree(knet);

	return ret;
#endif
}

static void __net_exit kni_exit_net(struct net *net)
{
#ifndef HAVE_SIMPLIFIED_PERNET_OPERATIONS
	struct kni_net *knet = net_generic(net, kni_net_id);

	kfree(knet);
#endif
}

static struct pernet_operations kni_net_ops = {
	.init = kni_init_net,
	.exit = kni_exit_net,
#ifdef HAVE_SIMPLIFIED_PERNET_OPERATIONS
	.id   = &kni_net_id,
	.size = sizeof(struct kni_net),
#endif
};

static int __init
kni_init(void)
{
	int rc;

	KNI_PRINT("######## DPDK kni module loading ########\n");

	if (kni_parse_kthread_mode() < 0) {
		KNI_ERR("Invalid parameter for kthread_mode\n");
		return -EINVAL;
	}

#ifdef HAVE_SIMPLIFIED_PERNET_OPERATIONS
	rc = register_pernet_subsys(&kni_net_ops);
#else
	rc = register_pernet_gen_subsys(&kni_net_id, &kni_net_ops);
#endif
	if (rc)
		return -EPERM;

	rc = misc_register(&kni_misc);
	if (rc != 0) {
		KNI_ERR("Misc registration failed\n");
		goto out;
	}

	/* Configure the lo mode according to the input parameter */
	kni_net_config_lo_mode(lo_mode);

	KNI_PRINT("######## DPDK kni module loaded  ########\n");

	return 0;

out:
#ifdef HAVE_SIMPLIFIED_PERNET_OPERATIONS
	unregister_pernet_subsys(&kni_net_ops);
#else
	register_pernet_gen_subsys(&kni_net_id, &kni_net_ops);
#endif
	return rc;
}

static void __exit
kni_exit(void)
{
	misc_deregister(&kni_misc);
#ifdef HAVE_SIMPLIFIED_PERNET_OPERATIONS
	unregister_pernet_subsys(&kni_net_ops);
#else
	register_pernet_gen_subsys(&kni_net_id, &kni_net_ops);
#endif
	KNI_PRINT("####### DPDK kni module unloaded  #######\n");
}

static int __init
kni_parse_kthread_mode(void)
{
	if (!kthread_mode)
		return 0;

	if (strcmp(kthread_mode, "single") == 0)
		return 0;
	else if (strcmp(kthread_mode, "multiple") == 0)
		multiple_kthread_on = 1;
	else
		return -1;

	return 0;
}

static int
kni_open(struct inode *inode, struct file *file)
{
	struct net *net = current->nsproxy->net_ns;
	struct kni_net *knet = net_generic(net, kni_net_id);

	/* kni device can be opened by one user only per netns */
	if (test_and_set_bit(KNI_DEV_IN_USE_BIT_NUM, &knet->device_in_use))
		return -EBUSY;

	/* Create kernel thread for single mode */
	if (multiple_kthread_on == 0) {
		KNI_PRINT("Single kernel thread for all KNI devices\n");
		/* Create kernel thread for RX */
		knet->kni_kthread = kthread_run(kni_thread_single, (void *)knet,
						"kni_single");
		if (IS_ERR(knet->kni_kthread)) {
			KNI_ERR("Unable to create kernel threaed\n");
			return PTR_ERR(knet->kni_kthread);
		}
	} else
		KNI_PRINT("Multiple kernel thread mode enabled\n");

	file->private_data = get_net(net);
	KNI_PRINT("/dev/kni opened\n");

	return 0;
}

static int
kni_release(struct inode *inode, struct file *file)
{
	struct net *net = file->private_data;
	struct kni_net *knet = net_generic(net, kni_net_id);
	struct kni_dev *dev, *n;

	/* Stop kernel thread for single mode */
	if (multiple_kthread_on == 0) {
		/* Stop kernel thread */
		kthread_stop(knet->kni_kthread);
		knet->kni_kthread = NULL;
	}

	down_write(&knet->kni_list_lock);
	list_for_each_entry_safe(dev, n, &knet->kni_list_head, list) {
		/* Stop kernel thread for multiple mode */
		if (multiple_kthread_on && dev->pthread != NULL) {
			kthread_stop(dev->pthread);
			dev->pthread = NULL;
		}

#ifdef RTE_KNI_VHOST
		kni_vhost_backend_release(dev);
#endif
		kni_dev_remove(dev);
		list_del(&dev->list);
	}
	up_write(&knet->kni_list_lock);

	/* Clear the bit of device in use */
	clear_bit(KNI_DEV_IN_USE_BIT_NUM, &knet->device_in_use);

	put_net(net);
	KNI_PRINT("/dev/kni closed\n");

	return 0;
}

static int
kni_thread_single(void *data)
{
	struct kni_net *knet = data;
	int j;
	struct kni_dev *dev;

	while (!kthread_should_stop()) {
		down_read(&knet->kni_list_lock);
		for (j = 0; j < KNI_RX_LOOP_NUM; j++) {
			list_for_each_entry(dev, &knet->kni_list_head, list) {
#ifdef RTE_KNI_VHOST
				kni_chk_vhost_rx(dev);
#else
				kni_net_rx(dev);
#endif
				kni_net_poll_resp(dev);
			}
		}
		up_read(&knet->kni_list_lock);
#ifdef RTE_KNI_PREEMPT_DEFAULT
		/* reschedule out for a while */
		schedule_timeout_interruptible(usecs_to_jiffies( \
				KNI_KTHREAD_RESCHEDULE_INTERVAL));
#endif
	}

	return 0;
}

static int
kni_thread_multiple(void *param)
{
	int j;
	struct kni_dev *dev = (struct kni_dev *)param;

	while (!kthread_should_stop()) {
		for (j = 0; j < KNI_RX_LOOP_NUM; j++) {
#ifdef RTE_KNI_VHOST
			kni_chk_vhost_rx(dev);
#else
			kni_net_rx(dev);
#endif
			kni_net_poll_resp(dev);
		}
#ifdef RTE_KNI_PREEMPT_DEFAULT
		schedule_timeout_interruptible(usecs_to_jiffies( \
				KNI_KTHREAD_RESCHEDULE_INTERVAL));
#endif
	}

	return 0;
}

static int
kni_dev_remove(struct kni_dev *dev)
{
	if (!dev)
		return -ENODEV;

	switch (dev->device_id) {
	#define RTE_PCI_DEV_ID_DECL_IGB(vend, dev) case (dev):
	#include <rte_pci_dev_ids.h>
		igb_kni_remove(dev->pci_dev);
		break;
	#define RTE_PCI_DEV_ID_DECL_IXGBE(vend, dev) case (dev):
	#include <rte_pci_dev_ids.h>
		ixgbe_kni_remove(dev->pci_dev);
		break;
	default:
		break;
	}

	if (dev->net_dev) {
		unregister_netdev(dev->net_dev);
		free_netdev(dev->net_dev);
	}

	return 0;
}

static int
kni_check_param(struct kni_dev *kni, struct rte_kni_device_info *dev)
{
	if (!kni || !dev)
		return -1;

	/* Check if network name has been used */
	if (!strncmp(kni->name, dev->name, RTE_KNI_NAMESIZE)) {
		KNI_ERR("KNI name %s duplicated\n", dev->name);
		return -1;
	}

	return 0;
}

static int
kni_ioctl_create(struct net *net,
		unsigned int ioctl_num, unsigned long ioctl_param)
{
	struct kni_net *knet = net_generic(net, kni_net_id);
	int ret;
	struct rte_kni_device_info dev_info;
	struct pci_dev *pci = NULL;
	struct pci_dev *found_pci = NULL;
	struct net_device *net_dev = NULL;
	struct net_device *lad_dev = NULL;
	struct kni_dev *kni, *dev, *n;

	printk(KERN_INFO "KNI: Creating kni...\n");
	/* Check the buffer size, to avoid warning */
	if (_IOC_SIZE(ioctl_num) > sizeof(dev_info))
		return -EINVAL;

	/* Copy kni info from user space */
	ret = copy_from_user(&dev_info, (void *)ioctl_param, sizeof(dev_info));
	if (ret) {
		KNI_ERR("copy_from_user in kni_ioctl_create");
		return -EIO;
	}

	/**
	 * Check if the cpu core id is valid for binding,
	 * for multiple kernel thread mode.
	 */
	if (multiple_kthread_on && dev_info.force_bind &&
				!cpu_online(dev_info.core_id)) {
		KNI_ERR("cpu %u is not online\n", dev_info.core_id);
		return -EINVAL;
	}

	/* Check if it has been created */
	down_read(&knet->kni_list_lock);
	list_for_each_entry_safe(dev, n, &knet->kni_list_head, list) {
		if (kni_check_param(dev, &dev_info) < 0) {
			up_read(&knet->kni_list_lock);
			return -EINVAL;
		}
	}
	up_read(&knet->kni_list_lock);

	net_dev = alloc_netdev(sizeof(struct kni_dev), dev_info.name,
#ifdef NET_NAME_UNKNOWN
							NET_NAME_UNKNOWN,
#endif
							kni_net_init);
	if (net_dev == NULL) {
		KNI_ERR("error allocating device \"%s\"\n", dev_info.name);
		return -EBUSY;
	}

	dev_net_set(net_dev, net);

	kni = netdev_priv(net_dev);

	kni->net_dev = net_dev;
	kni->group_id = dev_info.group_id;
	kni->core_id = dev_info.core_id;
	strncpy(kni->name, dev_info.name, RTE_KNI_NAMESIZE);

	/* Translate user space info into kernel space info */
	kni->tx_q = phys_to_virt(dev_info.tx_phys);
	kni->rx_q = phys_to_virt(dev_info.rx_phys);
	kni->alloc_q = phys_to_virt(dev_info.alloc_phys);
	kni->free_q = phys_to_virt(dev_info.free_phys);

	kni->req_q = phys_to_virt(dev_info.req_phys);
	kni->resp_q = phys_to_virt(dev_info.resp_phys);
	kni->sync_va = dev_info.sync_va;
	kni->sync_kva = phys_to_virt(dev_info.sync_phys);

	kni->mbuf_kva = phys_to_virt(dev_info.mbuf_phys);
	kni->mbuf_va = dev_info.mbuf_va;

#ifdef RTE_KNI_VHOST
	kni->vhost_queue = NULL;
	kni->vq_status = BE_STOP;
#endif
	kni->mbuf_size = dev_info.mbuf_size;

	KNI_PRINT("tx_phys:      0x%016llx, tx_q addr:      0x%p\n",
		(unsigned long long) dev_info.tx_phys, kni->tx_q);
	KNI_PRINT("rx_phys:      0x%016llx, rx_q addr:      0x%p\n",
		(unsigned long long) dev_info.rx_phys, kni->rx_q);
	KNI_PRINT("alloc_phys:   0x%016llx, alloc_q addr:   0x%p\n",
		(unsigned long long) dev_info.alloc_phys, kni->alloc_q);
	KNI_PRINT("free_phys:    0x%016llx, free_q addr:    0x%p\n",
		(unsigned long long) dev_info.free_phys, kni->free_q);
	KNI_PRINT("req_phys:     0x%016llx, req_q addr:     0x%p\n",
		(unsigned long long) dev_info.req_phys, kni->req_q);
	KNI_PRINT("resp_phys:    0x%016llx, resp_q addr:    0x%p\n",
		(unsigned long long) dev_info.resp_phys, kni->resp_q);
	KNI_PRINT("mbuf_phys:    0x%016llx, mbuf_kva:       0x%p\n",
		(unsigned long long) dev_info.mbuf_phys, kni->mbuf_kva);
	KNI_PRINT("mbuf_va:      0x%p\n", dev_info.mbuf_va);
	KNI_PRINT("mbuf_size:    %u\n", kni->mbuf_size);

	KNI_DBG("PCI: %02x:%02x.%02x %04x:%04x\n",
					dev_info.bus,
					dev_info.devid,
					dev_info.function,
					dev_info.vendor_id,
					dev_info.device_id);

	pci = pci_get_device(dev_info.vendor_id, dev_info.device_id, NULL);

	/* Support Ethtool */
	while (pci) {
		KNI_PRINT("pci_bus: %02x:%02x:%02x \n",
					pci->bus->number,
					PCI_SLOT(pci->devfn),
					PCI_FUNC(pci->devfn));

		if ((pci->bus->number == dev_info.bus) &&
			(PCI_SLOT(pci->devfn) == dev_info.devid) &&
			(PCI_FUNC(pci->devfn) == dev_info.function)) {
			found_pci = pci;
			switch (dev_info.device_id) {
			#define RTE_PCI_DEV_ID_DECL_IGB(vend, dev) case (dev):
			#include <rte_pci_dev_ids.h>
				ret = igb_kni_probe(found_pci, &lad_dev);
				break;
			#define RTE_PCI_DEV_ID_DECL_IXGBE(vend, dev) \
							case (dev):
			#include <rte_pci_dev_ids.h>
				ret = ixgbe_kni_probe(found_pci, &lad_dev);
				break;
			default:
				ret = -1;
				break;
			}

			KNI_DBG("PCI found: pci=0x%p, lad_dev=0x%p\n",
							pci, lad_dev);
			if (ret == 0) {
				kni->lad_dev = lad_dev;
				kni_set_ethtool_ops(kni->net_dev);
			} else {
				KNI_ERR("Device not supported by ethtool");
				kni->lad_dev = NULL;
			}

			kni->pci_dev = found_pci;
			kni->device_id = dev_info.device_id;
			break;
		}
		pci = pci_get_device(dev_info.vendor_id,
				dev_info.device_id, pci);
	}
	if (pci)
		pci_dev_put(pci);

	if (kni->lad_dev)
		memcpy(net_dev->dev_addr, kni->lad_dev->dev_addr, ETH_ALEN);
	else
		/*
		 * Generate random mac address. eth_random_addr() is the newer
		 * version of generating mac address in linux kernel.
		 */
		random_ether_addr(net_dev->dev_addr);

	ret = register_netdev(net_dev);
	if (ret) {
		KNI_ERR("error %i registering device \"%s\"\n",
					ret, dev_info.name);
		kni_dev_remove(kni);
		return -ENODEV;
	}

#ifdef RTE_KNI_VHOST
	kni_vhost_init(kni);
#endif

	/**
	 * Create a new kernel thread for multiple mode, set its core affinity,
	 * and finally wake it up.
	 */
	if (multiple_kthread_on) {
		kni->pthread = kthread_create(kni_thread_multiple,
					      (void *)kni,
					      "kni_%s", kni->name);
		if (IS_ERR(kni->pthread)) {
			kni_dev_remove(kni);
			return -ECANCELED;
		}
		if (dev_info.force_bind)
			kthread_bind(kni->pthread, kni->core_id);
		wake_up_process(kni->pthread);
	}

	down_write(&knet->kni_list_lock);
	list_add(&kni->list, &knet->kni_list_head);
	up_write(&knet->kni_list_lock);

	return 0;
}

static int
kni_ioctl_release(struct net *net,
		unsigned int ioctl_num, unsigned long ioctl_param)
{
	struct kni_net *knet = net_generic(net, kni_net_id);
	int ret = -EINVAL;
	struct kni_dev *dev, *n;
	struct rte_kni_device_info dev_info;

	if (_IOC_SIZE(ioctl_num) > sizeof(dev_info))
			return -EINVAL;

	ret = copy_from_user(&dev_info, (void *)ioctl_param, sizeof(dev_info));
	if (ret) {
		KNI_ERR("copy_from_user in kni_ioctl_release");
		return -EIO;
	}

	/* Release the network device according to its name */
	if (strlen(dev_info.name) == 0)
		return ret;

	down_write(&knet->kni_list_lock);
	list_for_each_entry_safe(dev, n, &knet->kni_list_head, list) {
		if (strncmp(dev->name, dev_info.name, RTE_KNI_NAMESIZE) != 0)
			continue;

		if (multiple_kthread_on && dev->pthread != NULL) {
			kthread_stop(dev->pthread);
			dev->pthread = NULL;
		}

#ifdef RTE_KNI_VHOST
		kni_vhost_backend_release(dev);
#endif
		kni_dev_remove(dev);
		list_del(&dev->list);
		ret = 0;
		break;
	}
	up_write(&knet->kni_list_lock);
	printk(KERN_INFO "KNI: %s release kni named %s\n",
		(ret == 0 ? "Successfully" : "Unsuccessfully"), dev_info.name);

	return ret;
}

static int
kni_ioctl(struct inode *inode,
	unsigned int ioctl_num,
	unsigned long ioctl_param)
{
	int ret = -EINVAL;
	struct net *net = current->nsproxy->net_ns;

	KNI_DBG("IOCTL num=0x%0x param=0x%0lx\n", ioctl_num, ioctl_param);

	/*
	 * Switch according to the ioctl called
	 */
	switch (_IOC_NR(ioctl_num)) {
	case _IOC_NR(RTE_KNI_IOCTL_TEST):
		/* For test only, not used */
		break;
	case _IOC_NR(RTE_KNI_IOCTL_CREATE):
		ret = kni_ioctl_create(net, ioctl_num, ioctl_param);
		break;
	case _IOC_NR(RTE_KNI_IOCTL_RELEASE):
		ret = kni_ioctl_release(net, ioctl_num, ioctl_param);
		break;
	default:
		KNI_DBG("IOCTL default\n");
		break;
	}

	return ret;
}

static int
kni_compat_ioctl(struct inode *inode,
		unsigned int ioctl_num,
		unsigned long ioctl_param)
{
	/* 32 bits app on 64 bits OS to be supported later */
	KNI_PRINT("Not implemented.\n");

	return -EINVAL;
}

module_init(kni_init);
module_exit(kni_exit);

module_param(lo_mode, charp, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(lo_mode,
"KNI loopback mode (default=lo_mode_none):\n"
"    lo_mode_none        Kernel loopback disabled\n"
"    lo_mode_fifo        Enable kernel loopback with fifo\n"
"    lo_mode_fifo_skb    Enable kernel loopback with fifo and skb buffer\n"
"\n"
);

module_param(kthread_mode, charp, S_IRUGO);
MODULE_PARM_DESC(kthread_mode,
"Kernel thread mode (default=single):\n"
"    single    Single kernel thread mode enabled.\n"
"    multiple  Multiple kernel thread mode enabled.\n"
"\n"
);