/*
 *
 * Copyright (c) 2011, Microsoft Corporation.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope 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., 59 Temple
 * Place - Suite 330, Boston, MA 02111-1307 USA.
 *
 * Authors:
 *   Haiyang Zhang <haiyangz@microsoft.com>
 *   Hank Janssen  <hjanssen@microsoft.com>
 *   K. Y. Srinivasan <kys@microsoft.com>
 *
 */

#ifndef _HYPERV_VMBUS_H
#define _HYPERV_VMBUS_H

#include <linux/list.h>
#include <asm/sync_bitops.h>
#include <asm/hyperv-tlfs.h>
#include <linux/atomic.h>
#include <linux/hyperv.h>
#include <linux/interrupt.h>

#include "hv_trace.h"

/*
 * Timeout for services such as KVP and fcopy.
 */
#define HV_UTIL_TIMEOUT 30

/*
 * Timeout for guest-host handshake for services.
 */
#define HV_UTIL_NEGO_TIMEOUT 55

/* Define synthetic interrupt controller flag constants. */
#define HV_EVENT_FLAGS_COUNT            (256 * 8)
#define HV_EVENT_FLAGS_LONG_COUNT       (256 / sizeof(unsigned long))

/*
 * Timer configuration register.
 */
union hv_timer_config {
        u64 as_uint64;
        struct {
                u64 enable:1;
                u64 periodic:1;
                u64 lazy:1;
                u64 auto_enable:1;
                u64 apic_vector:8;
                u64 direct_mode:1;
                u64 reserved_z0:3;
                u64 sintx:4;
                u64 reserved_z1:44;
        };
};


/* Define the synthetic interrupt controller event flags format. */
union hv_synic_event_flags {
        unsigned long flags[HV_EVENT_FLAGS_LONG_COUNT];
};

/* Define SynIC control register. */
union hv_synic_scontrol {
        u64 as_uint64;
        struct {
                u64 enable:1;
                u64 reserved:63;
        };
};

/* Define synthetic interrupt source. */
union hv_synic_sint {
        u64 as_uint64;
        struct {
                u64 vector:8;
                u64 reserved1:8;
                u64 masked:1;
                u64 auto_eoi:1;
                u64 reserved2:46;
        };
};

/* Define the format of the SIMP register */
union hv_synic_simp {
        u64 as_uint64;
        struct {
                u64 simp_enabled:1;
                u64 preserved:11;
                u64 base_simp_gpa:52;
        };
};

/* Define the format of the SIEFP register */
union hv_synic_siefp {
        u64 as_uint64;
        struct {
                u64 siefp_enabled:1;
                u64 preserved:11;
                u64 base_siefp_gpa:52;
        };
};

/* Definitions for the monitored notification facility */
union hv_monitor_trigger_group {
        u64 as_uint64;
        struct {
                u32 pending;
                u32 armed;
        };
};

struct hv_monitor_parameter {
        union hv_connection_id connectionid;
        u16 flagnumber;
        u16 rsvdz;
};

union hv_monitor_trigger_state {
        u32 asu32;

        struct {
                u32 group_enable:4;
                u32 rsvdz:28;
        };
};

/* struct hv_monitor_page Layout */
/* ------------------------------------------------------ */
/* | 0   | TriggerState (4 bytes) | Rsvd1 (4 bytes)     | */
/* | 8   | TriggerGroup[0]                              | */
/* | 10  | TriggerGroup[1]                              | */
/* | 18  | TriggerGroup[2]                              | */
/* | 20  | TriggerGroup[3]                              | */
/* | 28  | Rsvd2[0]                                     | */
/* | 30  | Rsvd2[1]                                     | */
/* | 38  | Rsvd2[2]                                     | */
/* | 40  | NextCheckTime[0][0]    | NextCheckTime[0][1] | */
/* | ...                                                | */
/* | 240 | Latency[0][0..3]                             | */
/* | 340 | Rsvz3[0]                                     | */
/* | 440 | Parameter[0][0]                              | */
/* | 448 | Parameter[0][1]                              | */
/* | ...                                                | */
/* | 840 | Rsvd4[0]                                     | */
/* ------------------------------------------------------ */
struct hv_monitor_page {
        union hv_monitor_trigger_state trigger_state;
        u32 rsvdz1;

        union hv_monitor_trigger_group trigger_group[4];
        u64 rsvdz2[3];

        s32 next_checktime[4][32];

        u16 latency[4][32];
        u64 rsvdz3[32];

        struct hv_monitor_parameter parameter[4][32];

        u8 rsvdz4[1984];
};

#define HV_HYPERCALL_PARAM_ALIGN        sizeof(u64)

/* Definition of the hv_post_message hypercall input structure. */
struct hv_input_post_message {
        union hv_connection_id connectionid;
        u32 reserved;
        u32 message_type;
        u32 payload_size;
        u64 payload[HV_MESSAGE_PAYLOAD_QWORD_COUNT];
};


enum {
        VMBUS_MESSAGE_CONNECTION_ID     = 1,
        VMBUS_MESSAGE_CONNECTION_ID_4   = 4,
        VMBUS_MESSAGE_PORT_ID           = 1,
        VMBUS_EVENT_CONNECTION_ID       = 2,
        VMBUS_EVENT_PORT_ID             = 2,
        VMBUS_MONITOR_CONNECTION_ID     = 3,
        VMBUS_MONITOR_PORT_ID           = 3,
        VMBUS_MESSAGE_SINT              = 2,
};

/*
 * Per cpu state for channel handling
 */
struct hv_per_cpu_context {
        void *synic_message_page;
        void *synic_event_page;
        /*
         * buffer to post messages to the host.
         */
        void *post_msg_page;

        /*
         * Starting with win8, we can take channel interrupts on any CPU;
         * we will manage the tasklet that handles events messages on a per CPU
         * basis.
         */
        struct tasklet_struct msg_dpc;

        /*
         * To optimize the mapping of relid to channel, maintain
         * per-cpu list of the channels based on their CPU affinity.
         */
        struct list_head chan_list;
        struct clock_event_device *clk_evt;
};

struct hv_context {
        /* We only support running on top of Hyper-V
         * So at this point this really can only contain the Hyper-V ID
         */
        u64 guestid;

        void *tsc_page;

        bool synic_initialized;

        struct hv_per_cpu_context __percpu *cpu_context;

        /*
         * To manage allocations in a NUMA node.
         * Array indexed by numa node ID.
         */
        struct cpumask *hv_numa_map;
};

extern struct hv_context hv_context;

/* Hv Interface */

extern int hv_init(void);

extern int hv_post_message(union hv_connection_id connection_id,
                         enum hv_message_type message_type,
                         void *payload, size_t payload_size);

extern int hv_synic_alloc(void);

extern void hv_synic_free(void);

extern int hv_synic_init(unsigned int cpu);

extern int hv_synic_cleanup(unsigned int cpu);

extern void hv_synic_clockevents_cleanup(void);

/* Interface */


int hv_ringbuffer_init(struct hv_ring_buffer_info *ring_info,
                       struct page *pages, u32 pagecnt);

void hv_ringbuffer_cleanup(struct hv_ring_buffer_info *ring_info);

int hv_ringbuffer_write(struct vmbus_channel *channel,
                        const struct kvec *kv_list, u32 kv_count);

int hv_ringbuffer_read(struct vmbus_channel *channel,
                       void *buffer, u32 buflen, u32 *buffer_actual_len,
                       u64 *requestid, bool raw);

/*
 * Maximum channels is determined by the size of the interrupt page
 * which is PAGE_SIZE. 1/2 of PAGE_SIZE is for send endpoint interrupt
 * and the other is receive endpoint interrupt
 */
#define MAX_NUM_CHANNELS        ((PAGE_SIZE >> 1) << 3) /* 16348 channels */

/* The value here must be in multiple of 32 */
/* TODO: Need to make this configurable */
#define MAX_NUM_CHANNELS_SUPPORTED      256


enum vmbus_connect_state {
        DISCONNECTED,
        CONNECTING,
        CONNECTED,
        DISCONNECTING
};

#define MAX_SIZE_CHANNEL_MESSAGE        HV_MESSAGE_PAYLOAD_BYTE_COUNT

struct vmbus_connection {
        /*
         * CPU on which the initial host contact was made.
         */
        int connect_cpu;

        u32 msg_conn_id;

        atomic_t offer_in_progress;

        enum vmbus_connect_state conn_state;

        atomic_t next_gpadl_handle;

        struct completion  unload_event;
        /*
         * Represents channel interrupts. Each bit position represents a
         * channel.  When a channel sends an interrupt via VMBUS, it finds its
         * bit in the sendInterruptPage, set it and calls Hv to generate a port
         * event. The other end receives the port event and parse the
         * recvInterruptPage to see which bit is set
         */
        void *int_page;
        void *send_int_page;
        void *recv_int_page;

        /*
         * 2 pages - 1st page for parent->child notification and 2nd
         * is child->parent notification
         */
        struct hv_monitor_page *monitor_pages[2];
        struct list_head chn_msg_list;
        spinlock_t channelmsg_lock;

        /* List of channels */
        struct list_head chn_list;
        struct mutex channel_mutex;

        struct workqueue_struct *work_queue;
};


struct vmbus_msginfo {
        /* Bookkeeping stuff */
        struct list_head msglist_entry;

        /* The message itself */
        unsigned char msg[0];
};


extern struct vmbus_connection vmbus_connection;

static inline void vmbus_send_interrupt(u32 relid)
{
        sync_set_bit(relid, vmbus_connection.send_int_page);
}

enum vmbus_message_handler_type {
        /* The related handler can sleep. */
        VMHT_BLOCKING = 0,

        /* The related handler must NOT sleep. */
        VMHT_NON_BLOCKING = 1,
};

struct vmbus_channel_message_table_entry {
        enum vmbus_channel_message_type message_type;
        enum vmbus_message_handler_type handler_type;
        void (*message_handler)(struct vmbus_channel_message_header *msg);
};

extern const struct vmbus_channel_message_table_entry
        channel_message_table[CHANNELMSG_COUNT];


/* General vmbus interface */

struct hv_device *vmbus_device_create(const uuid_le *type,
                                      const uuid_le *instance,
                                      struct vmbus_channel *channel);

int vmbus_device_register(struct hv_device *child_device_obj);
void vmbus_device_unregister(struct hv_device *device_obj);
int vmbus_add_channel_kobj(struct hv_device *device_obj,
                           struct vmbus_channel *channel);

struct vmbus_channel *relid2channel(u32 relid);

void vmbus_free_channels(void);

/* Connection interface */

int vmbus_connect(void);
void vmbus_disconnect(void);

int vmbus_post_msg(void *buffer, size_t buflen, bool can_sleep);

void vmbus_on_event(unsigned long data);
void vmbus_on_msg_dpc(unsigned long data);

int hv_kvp_init(struct hv_util_service *srv);
void hv_kvp_deinit(void);
void hv_kvp_onchannelcallback(void *context);

int hv_vss_init(struct hv_util_service *srv);
void hv_vss_deinit(void);
void hv_vss_onchannelcallback(void *context);

int hv_fcopy_init(struct hv_util_service *srv);
void hv_fcopy_deinit(void);
void hv_fcopy_onchannelcallback(void *context);
void vmbus_initiate_unload(bool crash);

static inline void hv_poll_channel(struct vmbus_channel *channel,
                                   void (*cb)(void *))
{
        if (!channel)
                return;

        if (in_interrupt() && (channel->target_cpu == smp_processor_id())) {
                cb(channel);
                return;
        }
        smp_call_function_single(channel->target_cpu, cb, channel, true);
}

enum hvutil_device_state {
        HVUTIL_DEVICE_INIT = 0,  /* driver is loaded, waiting for userspace */
        HVUTIL_READY,            /* userspace is registered */
        HVUTIL_HOSTMSG_RECEIVED, /* message from the host was received */
        HVUTIL_USERSPACE_REQ,    /* request to userspace was sent */
        HVUTIL_USERSPACE_RECV,   /* reply from userspace was received */
        HVUTIL_DEVICE_DYING,     /* driver unload is in progress */
};

#endif /* _HYPERV_VMBUS_H */