/*
 * blktap.h
 * 
 * Interfaces for the Xen block tap driver.
 * 
 * (c) 2004, Andrew Warfield, University of Cambridge
 * 
 */

#ifndef __BLKTAP_H__
#define __BLKTAP_H__

#include <linux/version.h>
#include <linux/blkdev.h>
#include <linux/config.h>
#include <linux/sched.h>
#include <linux/interrupt.h>
#include <asm-xen/ctrl_if.h>
#include <linux/slab.h>
#include <linux/blkdev.h>
#include <asm/io.h>
#include <asm/setup.h>
#include <asm/pgalloc.h>
#include <asm-xen/hypervisor.h>
#include <asm-xen/xen-public/io/blkif.h>
#include <asm-xen/xen-public/io/ring.h>

/* Used to signal to the backend that this is a tap domain. */
#define BLKTAP_COOKIE 0xbeadfeed

/* -------[ debug / pretty printing ]--------------------------------- */

#define PRINTK(_f, _a...) printk(KERN_ALERT "(file=%s, line=%d) " _f, \
                           __FILE__ , __LINE__ , ## _a )
#if 0
#define DPRINTK(_f, _a...) printk(KERN_ALERT "(file=%s, line=%d) " _f, \
                           __FILE__ , __LINE__ , ## _a )
#else
#define DPRINTK(_f, _a...) ((void)0)
#endif

#if 1
#define ASSERT(_p) \
    if ( !(_p) ) { printk("Assertion '%s' failed, line %d, file %s", #_p , \
    __LINE__, __FILE__); *(int*)0=0; }
#else
#define ASSERT(_p) ((void)0)
#endif

#define WPRINTK(fmt, args...) printk(KERN_WARNING "blk_tap: " fmt, ##args)


/* -------[ state descriptors ]--------------------------------------- */

#define BLKIF_STATE_CLOSED       0
#define BLKIF_STATE_DISCONNECTED 1
#define BLKIF_STATE_CONNECTED    2

/* -------[ connection tracking ]------------------------------------- */

#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,0)
#define VMALLOC_VMADDR(x) ((unsigned long)(x))
#endif

extern spinlock_t blkif_io_lock;

typedef struct blkif_st {
    /* Unique identifier for this interface. */
    domid_t             domid;
    unsigned int        handle;
    /* Physical parameters of the comms window. */
    unsigned long       shmem_frame;
    unsigned int        evtchn;
    /* Comms information. */
    blkif_back_ring_t   blk_ring;
    
    enum { DISCONNECTED, DISCONNECTING, CONNECTED } status;
    /*
     * DISCONNECT response is deferred until pending requests are ack'ed.
     * We therefore need to store the id from the original request.
     */    
    u8                  disconnect_rspid;
    struct blkif_st    *hash_next;
    struct list_head    blkdev_list;
    spinlock_t          blk_ring_lock;
    atomic_t            refcnt;
    struct work_struct work;
#ifdef CONFIG_XEN_BLKDEV_GRANT
    u16 shmem_handle;
    memory_t shmem_vaddr;
    grant_ref_t shmem_ref;
#endif
} blkif_t;

blkif_t *blkif_find_by_handle(domid_t domid, unsigned int handle);
void blkif_disconnect_complete(blkif_t *blkif);
#define blkif_get(_b) (atomic_inc(&(_b)->refcnt))
#define blkif_put(_b)                             \
    do {                                          \
        if ( atomic_dec_and_test(&(_b)->refcnt) ) \
            blkif_disconnect_complete(_b);        \
    } while (0)


/* -------[ active request tracking ]--------------------------------- */

typedef struct {
    blkif_t       *blkif;
    unsigned long  id;
    int            nr_pages;
    int            next_free;
} active_req_t;

typedef unsigned int ACTIVE_RING_IDX;

active_req_t *lookup_active_req(ACTIVE_RING_IDX idx);

extern inline unsigned int ID_TO_IDX(unsigned long id) 
{ 
    return ( id & 0x0000ffff );
}

extern inline domid_t ID_TO_DOM(unsigned long id) 
{ 
    return (id >> 16); 
}

void active_reqs_init(void);

/* -------[ interposition -> character device interface ]------------- */

/* /dev/xen/blktap resides at device number major=10, minor=200        */ 
#define BLKTAP_MINOR 202

/* size of the extra VMA area to map in attached pages. */
#define BLKTAP_VMA_PAGES BLKIF_RING_SIZE

/* blktap IOCTLs:                                                      */
#define BLKTAP_IOCTL_KICK_FE         1
#define BLKTAP_IOCTL_KICK_BE         2
#define BLKTAP_IOCTL_SETMODE         3
#define BLKTAP_IOCTL_PRINT_IDXS      100  

/* blktap switching modes: (Set with BLKTAP_IOCTL_SETMODE)             */
#define BLKTAP_MODE_PASSTHROUGH      0x00000000  /* default            */
#define BLKTAP_MODE_INTERCEPT_FE     0x00000001
#define BLKTAP_MODE_INTERCEPT_BE     0x00000002
#define BLKTAP_MODE_COPY_FE          0x00000004
#define BLKTAP_MODE_COPY_BE          0x00000008
#define BLKTAP_MODE_COPY_FE_PAGES    0x00000010
#define BLKTAP_MODE_COPY_BE_PAGES    0x00000020

#define BLKTAP_MODE_INTERPOSE \