// SPDX-License-Identifier: GPL-2.0+
/*
 * vsp1_uds.c  --  R-Car VSP1 Up and Down Scaler
 *
 * Copyright (C) 2013-2014 Renesas Electronics Corporation
 *
 * Contact: Laurent Pinchart (laurent.pinchart@ideasonboard.com)
 */

#include <linux/device.h>
#include <linux/gfp.h>

#include <media/v4l2-subdev.h>

#include "vsp1.h"
#include "vsp1_dl.h"
#include "vsp1_entity.h"
#include "vsp1_pipe.h"
#include "vsp1_uds.h"

#define UDS_MIN_SIZE                            4U
#define UDS_MAX_SIZE                            8190U

#define UDS_MIN_FACTOR                          0x0100
#define UDS_MAX_FACTOR                          0xffff

/* -----------------------------------------------------------------------------
 * Device Access
 */

static inline void vsp1_uds_write(struct vsp1_uds *uds,
                                  struct vsp1_dl_body *dlb, u32 reg, u32 data)
{
        vsp1_dl_body_write(dlb, reg + uds->entity.index * VI6_UDS_OFFSET, data);
}

/* -----------------------------------------------------------------------------
 * Scaling Computation
 */

void vsp1_uds_set_alpha(struct vsp1_entity *entity, struct vsp1_dl_body *dlb,
                        unsigned int alpha)
{
        struct vsp1_uds *uds = to_uds(&entity->subdev);

        vsp1_uds_write(uds, dlb, VI6_UDS_ALPVAL,
                       alpha << VI6_UDS_ALPVAL_VAL0_SHIFT);
}

/*
 * uds_output_size - Return the output size for an input size and scaling ratio
 * @input: input size in pixels
 * @ratio: scaling ratio in U4.12 fixed-point format
 */
static unsigned int uds_output_size(unsigned int input, unsigned int ratio)
{
        if (ratio > 4096) {
                /* Down-scaling */
                unsigned int mp;

                mp = ratio / 4096;
                mp = mp < 4 ? 1 : (mp < 8 ? 2 : 4);

                return (input - 1) / mp * mp * 4096 / ratio + 1;
        } else {
                /* Up-scaling */
                return (input - 1) * 4096 / ratio + 1;
        }
}

/*
 * uds_output_limits - Return the min and max output sizes for an input size
 * @input: input size in pixels
 * @minimum: minimum output size (returned)
 * @maximum: maximum output size (returned)
 */
static void uds_output_limits(unsigned int input,
                              unsigned int *minimum, unsigned int *maximum)
{
        *minimum = max(uds_output_size(input, UDS_MAX_FACTOR), UDS_MIN_SIZE);
        *maximum = min(uds_output_size(input, UDS_MIN_FACTOR), UDS_MAX_SIZE);
}

/*
 * uds_passband_width - Return the passband filter width for a scaling ratio
 * @ratio: scaling ratio in U4.12 fixed-point format
 */
static unsigned int uds_passband_width(unsigned int ratio)
{
        if (ratio >= 4096) {
                /* Down-scaling */
                unsigned int mp;

                mp = ratio / 4096;
                mp = mp < 4 ? 1 : (mp < 8 ? 2 : 4);

                return 64 * 4096 * mp / ratio;
        } else {
                /* Up-scaling */
                return 64;
        }
}

static unsigned int uds_compute_ratio(unsigned int input, unsigned int output)
{
        /* TODO: This is an approximation that will need to be refined. */
        return (input - 1) * 4096 / (output - 1);
}

/* -----------------------------------------------------------------------------
 * V4L2 Subdevice Pad Operations
 */

static int uds_enum_mbus_code(struct v4l2_subdev *subdev,
                              struct v4l2_subdev_state *sd_state,
                              struct v4l2_subdev_mbus_code_enum *code)
{
        static const unsigned int codes[] = {
                MEDIA_BUS_FMT_ARGB8888_1X32,
                MEDIA_BUS_FMT_AYUV8_1X32,
        };

        return vsp1_subdev_enum_mbus_code(subdev, sd_state, code, codes,
                                          ARRAY_SIZE(codes));
}

static int uds_enum_frame_size(struct v4l2_subdev *subdev,
                               struct v4l2_subdev_state *sd_state,
                               struct v4l2_subdev_frame_size_enum *fse)
{
        struct vsp1_uds *uds = to_uds(subdev);
        struct v4l2_subdev_state *state;
        struct v4l2_mbus_framefmt *format;
        int ret = 0;

        state = vsp1_entity_get_state(&uds->entity, sd_state, fse->which);
        if (!state)
                return -EINVAL;

        format = v4l2_subdev_state_get_format(state, UDS_PAD_SINK);

        mutex_lock(&uds->entity.lock);

        if (fse->index || fse->code != format->code) {
                ret = -EINVAL;
                goto done;
        }

        if (fse->pad == UDS_PAD_SINK) {
                fse->min_width = UDS_MIN_SIZE;
                fse->max_width = UDS_MAX_SIZE;
                fse->min_height = UDS_MIN_SIZE;
                fse->max_height = UDS_MAX_SIZE;
        } else {
                uds_output_limits(format->width, &fse->min_width,
                                  &fse->max_width);
                uds_output_limits(format->height, &fse->min_height,
                                  &fse->max_height);
        }

done:
        mutex_unlock(&uds->entity.lock);
        return ret;
}

static void uds_try_format(struct vsp1_uds *uds,
                           struct v4l2_subdev_state *sd_state,
                           unsigned int pad, struct v4l2_mbus_framefmt *fmt)
{
        struct v4l2_mbus_framefmt *format;
        unsigned int minimum;
        unsigned int maximum;

        switch (pad) {
        case UDS_PAD_SINK:
                /* Default to YUV if the requested format is not supported. */
                if (fmt->code != MEDIA_BUS_FMT_ARGB8888_1X32 &&
                    fmt->code != MEDIA_BUS_FMT_AYUV8_1X32)
                        fmt->code = MEDIA_BUS_FMT_AYUV8_1X32;

                vsp1_entity_adjust_color_space(fmt);

                fmt->width = clamp(fmt->width, UDS_MIN_SIZE, UDS_MAX_SIZE);
                fmt->height = clamp(fmt->height, UDS_MIN_SIZE, UDS_MAX_SIZE);
                break;

        case UDS_PAD_SOURCE:
                /* The UDS scales but can't perform format conversion. */
                format = v4l2_subdev_state_get_format(sd_state, UDS_PAD_SINK);
                fmt->code = format->code;

                fmt->colorspace = format->colorspace;
                fmt->xfer_func = format->xfer_func;
                fmt->ycbcr_enc = format->ycbcr_enc;
                fmt->quantization = format->quantization;

                uds_output_limits(format->width, &minimum, &maximum);
                fmt->width = clamp(fmt->width, minimum, maximum);
                uds_output_limits(format->height, &minimum, &maximum);
                fmt->height = clamp(fmt->height, minimum, maximum);
                break;
        }

        fmt->field = V4L2_FIELD_NONE;
}

static int uds_set_format(struct v4l2_subdev *subdev,
                          struct v4l2_subdev_state *sd_state,
                          struct v4l2_subdev_format *fmt)
{
        struct vsp1_uds *uds = to_uds(subdev);
        struct v4l2_subdev_state *state;
        struct v4l2_mbus_framefmt *format;
        int ret = 0;

        mutex_lock(&uds->entity.lock);

        state = vsp1_entity_get_state(&uds->entity, sd_state, fmt->which);
        if (!state) {
                ret = -EINVAL;
                goto done;
        }

        uds_try_format(uds, state, fmt->pad, &fmt->format);

        format = v4l2_subdev_state_get_format(state, fmt->pad);
        *format = fmt->format;

        if (fmt->pad == UDS_PAD_SINK) {
                /* Propagate the format to the source pad. */
                format = v4l2_subdev_state_get_format(state, UDS_PAD_SOURCE);
                *format = fmt->format;

                uds_try_format(uds, state, UDS_PAD_SOURCE, format);
        }

done:
        mutex_unlock(&uds->entity.lock);
        return ret;
}

/* -----------------------------------------------------------------------------
 * V4L2 Subdevice Operations
 */

static const struct v4l2_subdev_pad_ops uds_pad_ops = {
        .enum_mbus_code = uds_enum_mbus_code,
        .enum_frame_size = uds_enum_frame_size,
        .get_fmt = vsp1_subdev_get_pad_format,
        .set_fmt = uds_set_format,
};

static const struct v4l2_subdev_ops uds_ops = {
        .pad    = &uds_pad_ops,
};

/* -----------------------------------------------------------------------------
 * VSP1 Entity Operations
 */

static void uds_configure_stream(struct vsp1_entity *entity,
                                 struct v4l2_subdev_state *state,
                                 struct vsp1_pipeline *pipe,
                                 struct vsp1_dl_list *dl,
                                 struct vsp1_dl_body *dlb)
{
        struct vsp1_uds *uds = to_uds(&entity->subdev);
        const struct v4l2_mbus_framefmt *output;
        const struct v4l2_mbus_framefmt *input;
        unsigned int hscale;
        unsigned int vscale;
        bool multitap;

        input = v4l2_subdev_state_get_format(state, UDS_PAD_SINK);
        output = v4l2_subdev_state_get_format(state, UDS_PAD_SOURCE);

        hscale = uds_compute_ratio(input->width, output->width);
        vscale = uds_compute_ratio(input->height, output->height);

        dev_dbg(uds->entity.vsp1->dev, "hscale %u vscale %u\n", hscale, vscale);

        /*
         * Multi-tap scaling can't be enabled along with alpha scaling when
         * scaling down with a factor lower than or equal to 1/2 in either
         * direction.
         */
        if (uds->scale_alpha && (hscale >= 8192 || vscale >= 8192))
                multitap = false;
        else
                multitap = true;

        vsp1_uds_write(uds, dlb, VI6_UDS_CTRL,
                       (uds->scale_alpha ? VI6_UDS_CTRL_AON : 0) |
                       (multitap ? VI6_UDS_CTRL_BC : 0));

        vsp1_uds_write(uds, dlb, VI6_UDS_PASS_BWIDTH,
                       (uds_passband_width(hscale)
                                << VI6_UDS_PASS_BWIDTH_H_SHIFT) |
                       (uds_passband_width(vscale)
                                << VI6_UDS_PASS_BWIDTH_V_SHIFT));

        /* Set the scaling ratios. */
        vsp1_uds_write(uds, dlb, VI6_UDS_SCALE,
                       (hscale << VI6_UDS_SCALE_HFRAC_SHIFT) |
                       (vscale << VI6_UDS_SCALE_VFRAC_SHIFT));
}

static void uds_configure_partition(struct vsp1_entity *entity,
                                    struct vsp1_pipeline *pipe,
                                    const struct vsp1_partition *partition,
                                    struct vsp1_dl_list *dl,
                                    struct vsp1_dl_body *dlb)
{
        struct vsp1_uds *uds = to_uds(&entity->subdev);

        /* Input size clipping. */
        vsp1_uds_write(uds, dlb, VI6_UDS_HSZCLIP, VI6_UDS_HSZCLIP_HCEN |
                       (0 << VI6_UDS_HSZCLIP_HCL_OFST_SHIFT) |
                       (partition->uds_sink.width
                                << VI6_UDS_HSZCLIP_HCL_SIZE_SHIFT));

        /* Output size clipping. */
        vsp1_uds_write(uds, dlb, VI6_UDS_CLIP_SIZE,
                       (partition->uds_source.width
                                << VI6_UDS_CLIP_SIZE_HSIZE_SHIFT) |
                       (partition->uds_source.height
                                << VI6_UDS_CLIP_SIZE_VSIZE_SHIFT));
}

static unsigned int uds_max_width(struct vsp1_entity *entity,
                                  struct v4l2_subdev_state *state,
                                  struct vsp1_pipeline *pipe)
{
        const struct v4l2_mbus_framefmt *output;
        const struct v4l2_mbus_framefmt *input;
        unsigned int hscale;

        input = v4l2_subdev_state_get_format(state, UDS_PAD_SINK);
        output = v4l2_subdev_state_get_format(state, UDS_PAD_SOURCE);
        hscale = output->width / input->width;

        /*
         * The maximum width of the UDS is 304 pixels. These are input pixels
         * in the event of up-scaling, and output pixels in the event of
         * downscaling.
         *
         * To support overlapping partition windows we clamp at units of 256 and
         * the remaining pixels are reserved.
         */
        if (hscale <= 2)
                return 256;
        else if (hscale <= 4)
                return 512;
        else if (hscale <= 8)
                return 1024;
        else
                return 2048;
}

/* -----------------------------------------------------------------------------
 * Partition Algorithm Support
 */

static void uds_partition(struct vsp1_entity *entity,
                          struct v4l2_subdev_state *state,
                          struct vsp1_pipeline *pipe,
                          struct vsp1_partition *partition,
                          unsigned int partition_idx,
                          struct v4l2_rect *window)
{
        const struct v4l2_mbus_framefmt *output;
        const struct v4l2_mbus_framefmt *input;

        input = v4l2_subdev_state_get_format(state, UDS_PAD_SINK);
        output = v4l2_subdev_state_get_format(state, UDS_PAD_SOURCE);

        partition->uds_sink.width = window->width * input->width
                                  / output->width;
        partition->uds_sink.left = window->left * input->width
                                 / output->width;
        partition->uds_sink.height = input->height;
        partition->uds_sink.top = 0;

        partition->uds_source = *window;

        *window = partition->uds_sink;
}

static const struct vsp1_entity_operations uds_entity_ops = {
        .configure_stream = uds_configure_stream,
        .configure_partition = uds_configure_partition,
        .max_width = uds_max_width,
        .partition = uds_partition,
};

/* -----------------------------------------------------------------------------
 * Initialization and Cleanup
 */

struct vsp1_uds *vsp1_uds_create(struct vsp1_device *vsp1, unsigned int index)
{
        struct vsp1_uds *uds;
        char name[6];
        int ret;

        uds = devm_kzalloc(vsp1->dev, sizeof(*uds), GFP_KERNEL);
        if (uds == NULL)
                return ERR_PTR(-ENOMEM);

        uds->entity.ops = &uds_entity_ops;
        uds->entity.type = VSP1_ENTITY_UDS;
        uds->entity.index = index;

        sprintf(name, "uds.%u", index);
        ret = vsp1_entity_init(vsp1, &uds->entity, name, 2, &uds_ops,
                               MEDIA_ENT_F_PROC_VIDEO_SCALER);
        if (ret < 0)
                return ERR_PTR(ret);

        return uds;
}