/*
 * tcm.h
 *
 * TILER container manager specification and support functions for TI
 * TILER driver.
 *
 * Author: Lajos Molnar <molnar@ti.com>
 *
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * * Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 *
 * * Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 *
 * * Neither the name of Texas Instruments Incorporated nor the names of
 *   its contributors may be used to endorse or promote products derived
 *   from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
 * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef TCM_H
#define TCM_H

struct tcm;

/* point */
struct tcm_pt {
        u16 x;
        u16 y;
};

/* 1d or 2d area */
struct tcm_area {
        bool is2d;              /* whether area is 1d or 2d */
        struct tcm    *tcm;     /* parent */
        struct tcm_pt  p0;
        struct tcm_pt  p1;
};

struct tcm {
        u16 width, height;      /* container dimensions */
        int lut_id;             /* Lookup table identifier */

        unsigned int y_offset;  /* offset to use for y coordinates */

        spinlock_t lock;
        unsigned long *bitmap;
        size_t map_size;

        /* function table */
        s32 (*reserve_2d)(struct tcm *tcm, u16 height, u16 width, u16 align,
                          int16_t offset, uint16_t slot_bytes,
                          struct tcm_area *area);
        s32 (*reserve_1d)(struct tcm *tcm, u32 slots, struct tcm_area *area);
        s32 (*free)(struct tcm *tcm, struct tcm_area *area);
        void (*deinit)(struct tcm *tcm);
};

/*=============================================================================
    BASIC TILER CONTAINER MANAGER INTERFACE
=============================================================================*/

/*
 * NOTE:
 *
 * Since some basic parameter checking is done outside the TCM algorithms,
 * TCM implementation do NOT have to check the following:
 *
 *   area pointer is NULL
 *   width and height fits within container
 *   number of pages is more than the size of the container
 *
 */

struct tcm *sita_init(u16 width, u16 height);


/**
 * Deinitialize tiler container manager.
 *
 * @param tcm   Pointer to container manager.
 *
 * @return 0 on success, non-0 error value on error.  The call
 *         should free as much memory as possible and meaningful
 *         even on failure.  Some error codes: -ENODEV: invalid
 *         manager.
 */
static inline void tcm_deinit(struct tcm *tcm)
{
        if (tcm)
                tcm->deinit(tcm);
}

/**
 * Reserves a 2D area in the container.
 *
 * @param tcm           Pointer to container manager.
 * @param height        Height(in pages) of area to be reserved.
 * @param width         Width(in pages) of area to be reserved.
 * @param align         Alignment requirement for top-left corner of area. Not
 *                      all values may be supported by the container manager,
 *                      but it must support 0 (1), 32 and 64.
 *                      0 value is equivalent to 1.
 * @param offset        Offset requirement, in bytes.  This is the offset
 *                      from a 4KiB aligned virtual address.
 * @param slot_bytes    Width of slot in bytes
 * @param area          Pointer to where the reserved area should be stored.
 *
 * @return 0 on success.  Non-0 error code on failure.  Also,
 *         the tcm field of the area will be set to NULL on
 *         failure.  Some error codes: -ENODEV: invalid manager,
 *         -EINVAL: invalid area, -ENOMEM: not enough space for
 *          allocation.
 */
static inline s32 tcm_reserve_2d(struct tcm *tcm, u16 width, u16 height,
                                u16 align, int16_t offset, uint16_t slot_bytes,
                                struct tcm_area *area)
{
        /* perform rudimentary error checking */
        s32 res = tcm  == NULL ? -ENODEV :
                (area == NULL || width == 0 || height == 0 ||
                 /* align must be a 2 power */
                 (align & (align - 1))) ? -EINVAL :
                (height > tcm->height || width > tcm->width) ? -ENOMEM : 0;

        if (!res) {
                area->is2d = true;
                res = tcm->reserve_2d(tcm, height, width, align, offset,
                                        slot_bytes, area);
                area->tcm = res ? NULL : tcm;
        }

        return res;
}

/**
 * Reserves a 1D area in the container.
 *
 * @param tcm           Pointer to container manager.
 * @param slots         Number of (contiguous) slots to reserve.
 * @param area          Pointer to where the reserved area should be stored.
 *
 * @return 0 on success.  Non-0 error code on failure.  Also,
 *         the tcm field of the area will be set to NULL on
 *         failure.  Some error codes: -ENODEV: invalid manager,
 *         -EINVAL: invalid area, -ENOMEM: not enough space for
 *          allocation.
 */
static inline s32 tcm_reserve_1d(struct tcm *tcm, u32 slots,
                                 struct tcm_area *area)
{
        /* perform rudimentary error checking */
        s32 res = tcm  == NULL ? -ENODEV :
                (area == NULL || slots == 0) ? -EINVAL :
                slots > (tcm->width * (u32) tcm->height) ? -ENOMEM : 0;

        if (!res) {
                area->is2d = false;
                res = tcm->reserve_1d(tcm, slots, area);
                area->tcm = res ? NULL : tcm;
        }

        return res;
}

/**
 * Free a previously reserved area from the container.
 *
 * @param area  Pointer to area reserved by a prior call to
 *              tcm_reserve_1d or tcm_reserve_2d call, whether
 *              it was successful or not. (Note: all fields of
 *              the structure must match.)
 *
 * @return 0 on success.  Non-0 error code on failure.  Also, the tcm
 *         field of the area is set to NULL on success to avoid subsequent
 *         freeing.  This call will succeed even if supplying
 *         the area from a failed reserved call.
 */
static inline s32 tcm_free(struct tcm_area *area)
{
        s32 res = 0; /* free succeeds by default */

        if (area && area->tcm) {
                res = area->tcm->free(area->tcm, area);
                if (res == 0)
                        area->tcm = NULL;
        }

        return res;
}

/*=============================================================================
    HELPER FUNCTION FOR ANY TILER CONTAINER MANAGER
=============================================================================*/

/**
 * This method slices off the topmost 2D slice from the parent area, and stores
 * it in the 'slice' parameter.  The 'parent' parameter will get modified to
 * contain the remaining portion of the area.  If the whole parent area can
 * fit in a 2D slice, its tcm pointer is set to NULL to mark that it is no
 * longer a valid area.
 *
 * @param parent        Pointer to a VALID parent area that will get modified
 * @param slice         Pointer to the slice area that will get modified
 */
static inline void tcm_slice(struct tcm_area *parent, struct tcm_area *slice)
{
        *slice = *parent;

        /* check if we need to slice */
        if (slice->tcm && !slice->is2d &&
                slice->p0.y != slice->p1.y &&
                (slice->p0.x || (slice->p1.x != slice->tcm->width - 1))) {
                /* set end point of slice (start always remains) */
                slice->p1.x = slice->tcm->width - 1;
                slice->p1.y = (slice->p0.x) ? slice->p0.y : slice->p1.y - 1;
                /* adjust remaining area */
                parent->p0.x = 0;
                parent->p0.y = slice->p1.y + 1;
        } else {
                /* mark this as the last slice */
                parent->tcm = NULL;
        }
}

/* Verify if a tcm area is logically valid */
static inline bool tcm_area_is_valid(struct tcm_area *area)
{
        return area && area->tcm &&
                /* coordinate bounds */
                area->p1.x < area->tcm->width &&
                area->p1.y < area->tcm->height &&
                area->p0.y <= area->p1.y &&
                /* 1D coordinate relationship + p0.x check */
                ((!area->is2d &&
                  area->p0.x < area->tcm->width &&
                  area->p0.x + area->p0.y * area->tcm->width <=
                  area->p1.x + area->p1.y * area->tcm->width) ||
                 /* 2D coordinate relationship */
                 (area->is2d &&
                  area->p0.x <= area->p1.x));
}

/* see if a coordinate is within an area */
static inline bool __tcm_is_in(struct tcm_pt *p, struct tcm_area *a)
{
        u16 i;

        if (a->is2d) {
                return p->x >= a->p0.x && p->x <= a->p1.x &&
                       p->y >= a->p0.y && p->y <= a->p1.y;
        } else {
                i = p->x + p->y * a->tcm->width;
                return i >= a->p0.x + a->p0.y * a->tcm->width &&
                       i <= a->p1.x + a->p1.y * a->tcm->width;
        }
}

/* calculate area width */
static inline u16 __tcm_area_width(struct tcm_area *area)
{
        return area->p1.x - area->p0.x + 1;
}

/* calculate area height */
static inline u16 __tcm_area_height(struct tcm_area *area)
{
        return area->p1.y - area->p0.y + 1;
}

/* calculate number of slots in an area */
static inline u16 __tcm_sizeof(struct tcm_area *area)
{
        return area->is2d ?
                __tcm_area_width(area) * __tcm_area_height(area) :
                (area->p1.x - area->p0.x + 1) + (area->p1.y - area->p0.y) *
                                                        area->tcm->width;
}
#define tcm_sizeof(area) __tcm_sizeof(&(area))
#define tcm_awidth(area) __tcm_area_width(&(area))
#define tcm_aheight(area) __tcm_area_height(&(area))
#define tcm_is_in(pt, area) __tcm_is_in(&(pt), &(area))

/* limit a 1D area to the first N pages */
static inline s32 tcm_1d_limit(struct tcm_area *a, u32 num_pg)
{
        if (__tcm_sizeof(a) < num_pg)
                return -ENOMEM;
        if (!num_pg)
                return -EINVAL;

        a->p1.x = (a->p0.x + num_pg - 1) % a->tcm->width;
        a->p1.y = a->p0.y + ((a->p0.x + num_pg - 1) / a->tcm->width);
        return 0;
}

/**
 * Iterate through 2D slices of a valid area. Behaves
 * syntactically as a for(;;) statement.
 *
 * @param var           Name of a local variable of type 'struct
 *                      tcm_area *' that will get modified to
 *                      contain each slice.
 * @param area          Pointer to the VALID parent area. This
 *                      structure will not get modified
 *                      throughout the loop.
 *
 */
#define tcm_for_each_slice(var, area, safe) \
        for (safe = area, \
             tcm_slice(&safe, &var); \
             var.tcm; tcm_slice(&safe, &var))

#endif