/*
 * Copyright © 2016 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.
 *
 */

#ifndef __I915_GEM_CONTEXT_H__
#define __I915_GEM_CONTEXT_H__

#include <linux/bitops.h>
#include <linux/list.h>
#include <linux/radix-tree.h>

#include "i915_gem.h"
#include "i915_scheduler.h"

struct pid;

struct drm_device;
struct drm_file;

struct drm_i915_private;
struct drm_i915_file_private;
struct i915_hw_ppgtt;
struct i915_request;
struct i915_vma;
struct intel_ring;

#define DEFAULT_CONTEXT_HANDLE 0

struct intel_context;

struct intel_context_ops {
        void (*unpin)(struct intel_context *ce);
        void (*destroy)(struct intel_context *ce);
};

/**
 * struct i915_gem_context - client state
 *
 * The struct i915_gem_context represents the combined view of the driver and
 * logical hardware state for a particular client.
 */
struct i915_gem_context {
        /** i915: i915 device backpointer */
        struct drm_i915_private *i915;

        /** file_priv: owning file descriptor */
        struct drm_i915_file_private *file_priv;

        /**
         * @ppgtt: unique address space (GTT)
         *
         * In full-ppgtt mode, each context has its own address space ensuring
         * complete seperation of one client from all others.
         *
         * In other modes, this is a NULL pointer with the expectation that
         * the caller uses the shared global GTT.
         */
        struct i915_hw_ppgtt *ppgtt;

        /**
         * @pid: process id of creator
         *
         * Note that who created the context may not be the principle user,
         * as the context may be shared across a local socket. However,
         * that should only affect the default context, all contexts created
         * explicitly by the client are expected to be isolated.
         */
        pid_t pid;

        /**
         * @name: arbitrary name
         *
         * A name is constructed for the context from the creator's process
         * name, pid and user handle in order to uniquely identify the
         * context in messages.
         */
        const char *name;

        /** link: place with &drm_i915_private.context_list */
        struct list_head link;
        struct llist_node free_link;

        /**
         * @ref: reference count
         *
         * A reference to a context is held by both the client who created it
         * and on each request submitted to the hardware using the request
         * (to ensure the hardware has access to the state until it has
         * finished all pending writes). See i915_gem_context_get() and
         * i915_gem_context_put() for access.
         */
        struct kref ref;

        /**
         * @rcu: rcu_head for deferred freeing.
         */
        struct rcu_head rcu;

        /**
         * @user_flags: small set of booleans controlled by the user
         */
        unsigned long user_flags;
#define UCONTEXT_NO_ZEROMAP             0
#define UCONTEXT_NO_ERROR_CAPTURE       1
#define UCONTEXT_BANNABLE               2

        /**
         * @flags: small set of booleans
         */
        unsigned long flags;
#define CONTEXT_BANNED                  0
#define CONTEXT_CLOSED                  1
#define CONTEXT_FORCE_SINGLE_SUBMISSION 2

        /**
         * @hw_id: - unique identifier for the context
         *
         * The hardware needs to uniquely identify the context for a few
         * functions like fault reporting, PASID, scheduling. The
         * &drm_i915_private.context_hw_ida is used to assign a unqiue
         * id for the lifetime of the context.
         *
         * @hw_id_pin_count: - number of times this context had been pinned
         * for use (should be, at most, once per engine).
         *
         * @hw_id_link: - all contexts with an assigned id are tracked
         * for possible repossession.
         */
        unsigned int hw_id;
        atomic_t hw_id_pin_count;
        struct list_head hw_id_link;

        /**
         * @user_handle: userspace identifier
         *
         * A unique per-file identifier is generated from
         * &drm_i915_file_private.contexts.
         */
        u32 user_handle;

        struct i915_sched_attr sched;

        /** engine: per-engine logical HW state */
        struct intel_context {
                struct i915_gem_context *gem_context;
                struct i915_vma *state;
                struct intel_ring *ring;
                u32 *lrc_reg_state;
                u64 lrc_desc;
                int pin_count;

                const struct intel_context_ops *ops;
        } __engine[I915_NUM_ENGINES];

        /** ring_size: size for allocating the per-engine ring buffer */
        u32 ring_size;
        /** desc_template: invariant fields for the HW context descriptor */
        u32 desc_template;

        /** guilty_count: How many times this context has caused a GPU hang. */
        atomic_t guilty_count;
        /**
         * @active_count: How many times this context was active during a GPU
         * hang, but did not cause it.
         */
        atomic_t active_count;

#define CONTEXT_SCORE_GUILTY            10
#define CONTEXT_SCORE_BAN_THRESHOLD     40
        /** ban_score: Accumulated score of all hangs caused by this context. */
        atomic_t ban_score;

        /** remap_slice: Bitmask of cache lines that need remapping */
        u8 remap_slice;

        /** handles_vma: rbtree to look up our context specific obj/vma for
         * the user handle. (user handles are per fd, but the binding is
         * per vm, which may be one per context or shared with the global GTT)
         */
        struct radix_tree_root handles_vma;

        /** handles_list: reverse list of all the rbtree entries in use for
         * this context, which allows us to free all the allocations on
         * context close.
         */
        struct list_head handles_list;
};

static inline bool i915_gem_context_is_closed(const struct i915_gem_context *ctx)
{
        return test_bit(CONTEXT_CLOSED, &ctx->flags);
}

static inline void i915_gem_context_set_closed(struct i915_gem_context *ctx)
{
        GEM_BUG_ON(i915_gem_context_is_closed(ctx));
        set_bit(CONTEXT_CLOSED, &ctx->flags);
}

static inline bool i915_gem_context_no_error_capture(const struct i915_gem_context *ctx)
{
        return test_bit(UCONTEXT_NO_ERROR_CAPTURE, &ctx->user_flags);
}

static inline void i915_gem_context_set_no_error_capture(struct i915_gem_context *ctx)
{
        set_bit(UCONTEXT_NO_ERROR_CAPTURE, &ctx->user_flags);
}

static inline void i915_gem_context_clear_no_error_capture(struct i915_gem_context *ctx)
{
        clear_bit(UCONTEXT_NO_ERROR_CAPTURE, &ctx->user_flags);
}

static inline bool i915_gem_context_is_bannable(const struct i915_gem_context *ctx)
{
        return test_bit(UCONTEXT_BANNABLE, &ctx->user_flags);
}

static inline void i915_gem_context_set_bannable(struct i915_gem_context *ctx)
{
        set_bit(UCONTEXT_BANNABLE, &ctx->user_flags);
}

static inline void i915_gem_context_clear_bannable(struct i915_gem_context *ctx)
{
        clear_bit(UCONTEXT_BANNABLE, &ctx->user_flags);
}

static inline bool i915_gem_context_is_banned(const struct i915_gem_context *ctx)
{
        return test_bit(CONTEXT_BANNED, &ctx->flags);
}

static inline void i915_gem_context_set_banned(struct i915_gem_context *ctx)
{
        set_bit(CONTEXT_BANNED, &ctx->flags);
}

static inline bool i915_gem_context_force_single_submission(const struct i915_gem_context *ctx)
{
        return test_bit(CONTEXT_FORCE_SINGLE_SUBMISSION, &ctx->flags);
}

static inline void i915_gem_context_set_force_single_submission(struct i915_gem_context *ctx)
{
        __set_bit(CONTEXT_FORCE_SINGLE_SUBMISSION, &ctx->flags);
}

int __i915_gem_context_pin_hw_id(struct i915_gem_context *ctx);
static inline int i915_gem_context_pin_hw_id(struct i915_gem_context *ctx)
{
        if (atomic_inc_not_zero(&ctx->hw_id_pin_count))
                return 0;

        return __i915_gem_context_pin_hw_id(ctx);
}

static inline void i915_gem_context_unpin_hw_id(struct i915_gem_context *ctx)
{
        GEM_BUG_ON(atomic_read(&ctx->hw_id_pin_count) == 0u);
        atomic_dec(&ctx->hw_id_pin_count);
}

static inline bool i915_gem_context_is_default(const struct i915_gem_context *c)
{
        return c->user_handle == DEFAULT_CONTEXT_HANDLE;
}

static inline bool i915_gem_context_is_kernel(struct i915_gem_context *ctx)
{
        return !ctx->file_priv;
}

static inline struct intel_context *
to_intel_context(struct i915_gem_context *ctx,
                 const struct intel_engine_cs *engine)
{
        return &ctx->__engine[engine->id];
}

static inline struct intel_context *
intel_context_pin(struct i915_gem_context *ctx, struct intel_engine_cs *engine)
{
        return engine->context_pin(engine, ctx);
}

static inline void __intel_context_pin(struct intel_context *ce)
{
        GEM_BUG_ON(!ce->pin_count);
        ce->pin_count++;
}

static inline void intel_context_unpin(struct intel_context *ce)
{
        GEM_BUG_ON(!ce->pin_count);
        if (--ce->pin_count)
                return;

        GEM_BUG_ON(!ce->ops);
        ce->ops->unpin(ce);
}

/* i915_gem_context.c */
int __must_check i915_gem_contexts_init(struct drm_i915_private *dev_priv);
void i915_gem_contexts_lost(struct drm_i915_private *dev_priv);
void i915_gem_contexts_fini(struct drm_i915_private *dev_priv);

int i915_gem_context_open(struct drm_i915_private *i915,
                          struct drm_file *file);
void i915_gem_context_close(struct drm_file *file);

int i915_switch_context(struct i915_request *rq);
int i915_gem_switch_to_kernel_context(struct drm_i915_private *dev_priv);

void i915_gem_context_release(struct kref *ctx_ref);
struct i915_gem_context *
i915_gem_context_create_gvt(struct drm_device *dev);

int i915_gem_context_create_ioctl(struct drm_device *dev, void *data,
                                  struct drm_file *file);
int i915_gem_context_destroy_ioctl(struct drm_device *dev, void *data,
                                   struct drm_file *file);
int i915_gem_context_getparam_ioctl(struct drm_device *dev, void *data,
                                    struct drm_file *file_priv);
int i915_gem_context_setparam_ioctl(struct drm_device *dev, void *data,
                                    struct drm_file *file_priv);
int i915_gem_context_reset_stats_ioctl(struct drm_device *dev, void *data,
                                       struct drm_file *file);

struct i915_gem_context *
i915_gem_context_create_kernel(struct drm_i915_private *i915, int prio);

static inline struct i915_gem_context *
i915_gem_context_get(struct i915_gem_context *ctx)
{
        kref_get(&ctx->ref);
        return ctx;
}

static inline void i915_gem_context_put(struct i915_gem_context *ctx)
{
        kref_put(&ctx->ref, i915_gem_context_release);
}

#endif /* !__I915_GEM_CONTEXT_H__ */