/* SPDX-License-Identifier: GPL-2.0 */
/*
 * Private stuff for vfio_ccw driver
 *
 * Copyright IBM Corp. 2017
 * Copyright Red Hat, Inc. 2019
 *
 * Author(s): Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
 *            Xiao Feng Ren <renxiaof@linux.vnet.ibm.com>
 *            Cornelia Huck <cohuck@redhat.com>
 */

#ifndef _VFIO_CCW_PRIVATE_H_
#define _VFIO_CCW_PRIVATE_H_

#include <linux/completion.h>
#include <linux/eventfd.h>
#include <linux/workqueue.h>
#include <linux/vfio_ccw.h>
#include <linux/vfio.h>
#include <linux/mdev.h>
#include <asm/crw.h>
#include <asm/debug.h>

#include "css.h"
#include "vfio_ccw_cp.h"

#define VFIO_CCW_OFFSET_SHIFT   10
#define VFIO_CCW_OFFSET_TO_INDEX(off)   (off >> VFIO_CCW_OFFSET_SHIFT)
#define VFIO_CCW_INDEX_TO_OFFSET(index) ((u64)(index) << VFIO_CCW_OFFSET_SHIFT)
#define VFIO_CCW_OFFSET_MASK    (((u64)(1) << VFIO_CCW_OFFSET_SHIFT) - 1)

/* capability chain handling similar to vfio-pci */
struct vfio_ccw_private;
struct vfio_ccw_region;

struct vfio_ccw_regops {
        ssize_t (*read)(struct vfio_ccw_private *private, char __user *buf,
                        size_t count, loff_t *ppos);
        ssize_t (*write)(struct vfio_ccw_private *private,
                         const char __user *buf, size_t count, loff_t *ppos);
        void    (*release)(struct vfio_ccw_private *private,
                           struct vfio_ccw_region *region);
};

struct vfio_ccw_region {
        u32                             type;
        u32                             subtype;
        const struct vfio_ccw_regops    *ops;
        void                            *data;
        size_t                          size;
        u32                             flags;
};

int vfio_ccw_register_dev_region(struct vfio_ccw_private *private,
                                 unsigned int subtype,
                                 const struct vfio_ccw_regops *ops,
                                 size_t size, u32 flags, void *data);
void vfio_ccw_unregister_dev_regions(struct vfio_ccw_private *private);

int vfio_ccw_register_async_dev_regions(struct vfio_ccw_private *private);
int vfio_ccw_register_schib_dev_regions(struct vfio_ccw_private *private);
int vfio_ccw_register_crw_dev_regions(struct vfio_ccw_private *private);

struct vfio_ccw_crw {
        struct list_head        next;
        struct crw              crw;
};

/**
 * struct vfio_ccw_parent
 *
 * @dev: embedded device struct
 * @parent: parent data structures for mdevs created
 * @mdev_type(s): identifying information for mdevs created
 */
struct vfio_ccw_parent {
        struct device           dev;

        struct mdev_parent      parent;
        struct mdev_type        mdev_type;
        struct mdev_type        *mdev_types;
};

/**
 * struct vfio_ccw_private
 * @vdev: Embedded VFIO device
 * @state: internal state of the device
 * @completion: synchronization helper of the I/O completion
 * @io_region: MMIO region to input/output I/O arguments/results
 * @io_mutex: protect against concurrent update of I/O regions
 * @region: additional regions for other subchannel operations
 * @cmd_region: MMIO region for asynchronous I/O commands other than START
 * @schib_region: MMIO region for SCHIB information
 * @crw_region: MMIO region for getting channel report words
 * @num_regions: number of additional regions
 * @cp: channel program for the current I/O operation
 * @irb: irb info received from interrupt
 * @scsw: scsw info
 * @io_trigger: eventfd ctx for signaling userspace I/O results
 * @crw_trigger: eventfd ctx for signaling userspace CRW information
 * @req_trigger: eventfd ctx for signaling userspace to return device
 * @io_work: work for deferral process of I/O handling
 * @crw_work: work for deferral process of CRW handling
 */
struct vfio_ccw_private {
        struct vfio_device vdev;
        int                     state;
        struct completion       *completion;
        struct ccw_io_region    *io_region;
        struct mutex            io_mutex;
        struct vfio_ccw_region *region;
        struct ccw_cmd_region   *cmd_region;
        struct ccw_schib_region *schib_region;
        struct ccw_crw_region   *crw_region;
        int num_regions;

        struct channel_program  cp;
        struct irb              irb;
        union scsw              scsw;
        struct list_head        crw;

        struct eventfd_ctx      *io_trigger;
        struct eventfd_ctx      *crw_trigger;
        struct eventfd_ctx      *req_trigger;
        struct work_struct      io_work;
        struct work_struct      crw_work;
} __aligned(8);

int vfio_ccw_sch_quiesce(struct subchannel *sch);
void vfio_ccw_sch_io_todo(struct work_struct *work);
void vfio_ccw_crw_todo(struct work_struct *work);

extern struct mdev_driver vfio_ccw_mdev_driver;

/*
 * States of the device statemachine.
 */
enum vfio_ccw_state {
        VFIO_CCW_STATE_NOT_OPER,
        VFIO_CCW_STATE_STANDBY,
        VFIO_CCW_STATE_IDLE,
        VFIO_CCW_STATE_CP_PROCESSING,
        VFIO_CCW_STATE_CP_PENDING,
        /* last element! */
        NR_VFIO_CCW_STATES
};

/*
 * Asynchronous events of the device statemachine.
 */
enum vfio_ccw_event {
        VFIO_CCW_EVENT_NOT_OPER,
        VFIO_CCW_EVENT_IO_REQ,
        VFIO_CCW_EVENT_INTERRUPT,
        VFIO_CCW_EVENT_ASYNC_REQ,
        VFIO_CCW_EVENT_OPEN,
        VFIO_CCW_EVENT_CLOSE,
        /* last element! */
        NR_VFIO_CCW_EVENTS
};

/*
 * Action called through jumptable.
 */
typedef void (fsm_func_t)(struct vfio_ccw_private *, enum vfio_ccw_event);
extern fsm_func_t *vfio_ccw_jumptable[NR_VFIO_CCW_STATES][NR_VFIO_CCW_EVENTS];

static inline void vfio_ccw_fsm_event(struct vfio_ccw_private *private,
                                      enum vfio_ccw_event event)
{
        struct subchannel *sch = to_subchannel(private->vdev.dev->parent);

        if (sch)
                trace_vfio_ccw_fsm_event(sch->schid, private->state, event);
        vfio_ccw_jumptable[private->state][event](private, event);
}

extern struct workqueue_struct *vfio_ccw_work_q;
extern struct kmem_cache *vfio_ccw_io_region;
extern struct kmem_cache *vfio_ccw_cmd_region;
extern struct kmem_cache *vfio_ccw_schib_region;
extern struct kmem_cache *vfio_ccw_crw_region;

/* s390 debug feature, similar to base cio */
extern debug_info_t *vfio_ccw_debug_msg_id;
extern debug_info_t *vfio_ccw_debug_trace_id;

#define VFIO_CCW_TRACE_EVENT(imp, txt) \
                debug_text_event(vfio_ccw_debug_trace_id, imp, txt)

#define VFIO_CCW_MSG_EVENT(imp, args...) \
                debug_sprintf_event(vfio_ccw_debug_msg_id, imp, ##args)

static inline void VFIO_CCW_HEX_EVENT(int level, void *data, int length)
{
        debug_event(vfio_ccw_debug_trace_id, level, data, length);
}

#endif