// SPDX-License-Identifier: GPL-2.0-or-later
/*

    bttv-risc.c  --  interfaces to other kernel modules

    bttv risc code handling
        - memory management
        - generation

    (c) 2000-2003 Gerd Knorr <kraxel@bytesex.org>


*/

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/pci.h>
#include <linux/vmalloc.h>
#include <linux/interrupt.h>
#include <linux/pgtable.h>
#include <asm/page.h>
#include <media/v4l2-ioctl.h>

#include "bttvp.h"

#define VCR_HACK_LINES 4

/* ---------------------------------------------------------- */
/* risc code generators                                       */

int
bttv_risc_packed(struct bttv *btv, struct btcx_riscmem *risc,
                 struct scatterlist *sglist,
                 unsigned int offset, unsigned int bpl,
                 unsigned int padding, unsigned int skip_lines,
                 unsigned int store_lines)
{
        u32 instructions,line,todo;
        struct scatterlist *sg;
        __le32 *rp;
        int rc;

        /* estimate risc mem: worst case is one write per page border +
           one write per scan line + sync + jump (all 2 dwords).  padding
           can cause next bpl to start close to a page border.  First DMA
           region may be smaller than PAGE_SIZE */
        instructions  = skip_lines * 4;
        instructions += (1 + ((bpl + padding) * store_lines)
                         / PAGE_SIZE + store_lines) * 8;
        instructions += 2 * 8;
        if ((rc = btcx_riscmem_alloc(btv->c.pci,risc,instructions)) < 0)
                return rc;

        /* sync instruction */
        rp = risc->cpu;
        *(rp++) = cpu_to_le32(BT848_RISC_SYNC|BT848_FIFO_STATUS_FM1);
        *(rp++) = cpu_to_le32(0);

        while (skip_lines-- > 0) {
                *(rp++) = cpu_to_le32(BT848_RISC_SKIP | BT848_RISC_SOL |
                                      BT848_RISC_EOL | bpl);
        }

        /* scan lines */
        sg = sglist;
        for (line = 0; line < store_lines; line++) {
                if ((line >= (store_lines - VCR_HACK_LINES)) &&
                    btv->opt_vcr_hack)
                        continue;
                while (offset && offset >= sg_dma_len(sg)) {
                        offset -= sg_dma_len(sg);
                        sg = sg_next(sg);
                }
                if (bpl <= sg_dma_len(sg)-offset) {
                        /* fits into current chunk */
                        *(rp++)=cpu_to_le32(BT848_RISC_WRITE|BT848_RISC_SOL|
                                            BT848_RISC_EOL|bpl);
                        *(rp++)=cpu_to_le32(sg_dma_address(sg)+offset);
                        offset+=bpl;
                } else {
                        /* scanline needs to be split */
                        todo = bpl;
                        *(rp++)=cpu_to_le32(BT848_RISC_WRITE|BT848_RISC_SOL|
                                            (sg_dma_len(sg)-offset));
                        *(rp++)=cpu_to_le32(sg_dma_address(sg)+offset);
                        todo -= (sg_dma_len(sg)-offset);
                        offset = 0;
                        sg = sg_next(sg);
                        while (todo > sg_dma_len(sg)) {
                                *(rp++)=cpu_to_le32(BT848_RISC_WRITE|
                                                    sg_dma_len(sg));
                                *(rp++)=cpu_to_le32(sg_dma_address(sg));
                                todo -= sg_dma_len(sg);
                                sg = sg_next(sg);
                        }
                        *(rp++)=cpu_to_le32(BT848_RISC_WRITE|BT848_RISC_EOL|
                                            todo);
                        *(rp++)=cpu_to_le32(sg_dma_address(sg));
                        offset += todo;
                }
                offset += padding;
        }

        /* save pointer to jmp instruction address */
        risc->jmp = rp;
        WARN_ON((risc->jmp - risc->cpu + 2) * sizeof(*risc->cpu) > risc->size);
        return 0;
}

static int
bttv_risc_planar(struct bttv *btv, struct btcx_riscmem *risc,
                 struct scatterlist *sglist,
                 unsigned int yoffset,  unsigned int ybpl,
                 unsigned int ypadding, unsigned int ylines,
                 unsigned int uoffset,  unsigned int voffset,
                 unsigned int hshift,   unsigned int vshift,
                 unsigned int cpadding)
{
        unsigned int instructions,line,todo,ylen,chroma;
        __le32 *rp;
        u32 ri;
        struct scatterlist *ysg;
        struct scatterlist *usg;
        struct scatterlist *vsg;
        int topfield = (0 == yoffset);
        int rc;

        /* estimate risc mem: worst case is one write per page border +
           one write per scan line (5 dwords)
           plus sync + jump (2 dwords) */
        instructions  = ((3 + (ybpl + ypadding) * ylines * 2)
                         / PAGE_SIZE) + ylines;
        instructions += 2;
        if ((rc = btcx_riscmem_alloc(btv->c.pci,risc,instructions*4*5)) < 0)
                return rc;

        /* sync instruction */
        rp = risc->cpu;
        *(rp++) = cpu_to_le32(BT848_RISC_SYNC|BT848_FIFO_STATUS_FM3);
        *(rp++) = cpu_to_le32(0);

        /* scan lines */
        ysg = sglist;
        usg = sglist;
        vsg = sglist;
        for (line = 0; line < ylines; line++) {
                if ((btv->opt_vcr_hack) &&
                    (line >= (ylines - VCR_HACK_LINES)))
                        continue;
                switch (vshift) {
                case 0:
                        chroma = 1;
                        break;
                case 1:
                        if (topfield)
                                chroma = ((line & 1) == 0);
                        else
                                chroma = ((line & 1) == 1);
                        break;
                case 2:
                        if (topfield)
                                chroma = ((line & 3) == 0);
                        else
                                chroma = ((line & 3) == 2);
                        break;
                default:
                        chroma = 0;
                        break;
                }

                for (todo = ybpl; todo > 0; todo -= ylen) {
                        /* go to next sg entry if needed */
                        while (yoffset && yoffset >= sg_dma_len(ysg)) {
                                yoffset -= sg_dma_len(ysg);
                                ysg = sg_next(ysg);
                        }

                        /* calculate max number of bytes we can write */
                        ylen = todo;
                        if (yoffset + ylen > sg_dma_len(ysg))
                                ylen = sg_dma_len(ysg) - yoffset;
                        if (chroma) {
                                while (uoffset && uoffset >= sg_dma_len(usg)) {
                                        uoffset -= sg_dma_len(usg);
                                        usg = sg_next(usg);
                                }
                                while (voffset && voffset >= sg_dma_len(vsg)) {
                                        voffset -= sg_dma_len(vsg);
                                        vsg = sg_next(vsg);
                                }

                                if (uoffset + (ylen>>hshift) > sg_dma_len(usg))
                                        ylen = (sg_dma_len(usg) - uoffset) << hshift;
                                if (voffset + (ylen>>hshift) > sg_dma_len(vsg))
                                        ylen = (sg_dma_len(vsg) - voffset) << hshift;
                                ri = BT848_RISC_WRITE123;
                        } else {
                                ri = BT848_RISC_WRITE1S23;
                        }
                        if (ybpl == todo)
                                ri |= BT848_RISC_SOL;
                        if (ylen == todo)
                                ri |= BT848_RISC_EOL;

                        /* write risc instruction */
                        *(rp++)=cpu_to_le32(ri | ylen);
                        *(rp++)=cpu_to_le32(((ylen >> hshift) << 16) |
                                            (ylen >> hshift));
                        *(rp++)=cpu_to_le32(sg_dma_address(ysg)+yoffset);
                        yoffset += ylen;
                        if (chroma) {
                                *(rp++)=cpu_to_le32(sg_dma_address(usg)+uoffset);
                                uoffset += ylen >> hshift;
                                *(rp++)=cpu_to_le32(sg_dma_address(vsg)+voffset);
                                voffset += ylen >> hshift;
                        }
                }
                yoffset += ypadding;
                if (chroma) {
                        uoffset += cpadding;
                        voffset += cpadding;
                }
        }

        /* save pointer to jmp instruction address */
        risc->jmp = rp;
        WARN_ON((risc->jmp - risc->cpu + 2) * sizeof(*risc->cpu) > risc->size);
        return 0;
}

/* ---------------------------------------------------------- */

static void
bttv_calc_geo_old(struct bttv *btv, struct bttv_geometry *geo,
                  int width, int height, int interleaved,
                  const struct bttv_tvnorm *tvnorm)
{
        u32 xsf, sr;
        int vdelay;

        int swidth       = tvnorm->swidth;
        int totalwidth   = tvnorm->totalwidth;
        int scaledtwidth = tvnorm->scaledtwidth;

        if (btv->input == btv->dig) {
                swidth       = 720;
                totalwidth   = 858;
                scaledtwidth = 858;
        }

        vdelay = tvnorm->vdelay;

        xsf = (width*scaledtwidth)/swidth;
        geo->hscale =  ((totalwidth*4096UL)/xsf-4096);
        geo->hdelay =  tvnorm->hdelayx1;
        geo->hdelay =  (geo->hdelay*width)/swidth;
        geo->hdelay &= 0x3fe;
        sr = ((tvnorm->sheight >> (interleaved?0:1))*512)/height - 512;
        geo->vscale =  (0x10000UL-sr) & 0x1fff;
        geo->crop   =  ((width>>8)&0x03) | ((geo->hdelay>>6)&0x0c) |
                ((tvnorm->sheight>>4)&0x30) | ((vdelay>>2)&0xc0);
        geo->vscale |= interleaved ? (BT848_VSCALE_INT<<8) : 0;
        geo->vdelay  =  vdelay;
        geo->width   =  width;
        geo->sheight =  tvnorm->sheight;
        geo->vtotal  =  tvnorm->vtotal;

        if (btv->opt_combfilter) {
                geo->vtc  = (width < 193) ? 2 : ((width < 385) ? 1 : 0);
                geo->comb = (width < 769) ? 1 : 0;
        } else {
                geo->vtc  = 0;
                geo->comb = 0;
        }
}

static void
bttv_calc_geo           (struct bttv *                  btv,
                         struct bttv_geometry *         geo,
                         unsigned int                   width,
                         unsigned int                   height,
                         int                            both_fields,
                         const struct bttv_tvnorm *     tvnorm,
                         const struct v4l2_rect *       crop)
{
        unsigned int c_width;
        unsigned int c_height;
        u32 sr;

        if ((crop->left == tvnorm->cropcap.defrect.left
             && crop->top == tvnorm->cropcap.defrect.top
             && crop->width == tvnorm->cropcap.defrect.width
             && crop->height == tvnorm->cropcap.defrect.height
             && width <= tvnorm->swidth /* see PAL-Nc et al */)
            || btv->input == btv->dig) {
                bttv_calc_geo_old(btv, geo, width, height,
                                  both_fields, tvnorm);
                return;
        }

        /* For bug compatibility the image size checks permit scale
           factors > 16. See bttv_crop_calc_limits(). */
        c_width = min((unsigned int) crop->width, width * 16);
        c_height = min((unsigned int) crop->height, height * 16);

        geo->width = width;
        geo->hscale = (c_width * 4096U + (width >> 1)) / width - 4096;
        /* Even to store Cb first, odd for Cr. */
        geo->hdelay = ((crop->left * width + c_width) / c_width) & ~1;

        geo->sheight = c_height;
        geo->vdelay = crop->top - tvnorm->cropcap.bounds.top + MIN_VDELAY;
        sr = c_height >> !both_fields;
        sr = (sr * 512U + (height >> 1)) / height - 512;
        geo->vscale = (0x10000UL - sr) & 0x1fff;
        geo->vscale |= both_fields ? (BT848_VSCALE_INT << 8) : 0;
        geo->vtotal = tvnorm->vtotal;

        geo->crop = (((geo->width   >> 8) & 0x03) |
                     ((geo->hdelay  >> 6) & 0x0c) |
                     ((geo->sheight >> 4) & 0x30) |
                     ((geo->vdelay  >> 2) & 0xc0));

        if (btv->opt_combfilter) {
                geo->vtc  = (width < 193) ? 2 : ((width < 385) ? 1 : 0);
                geo->comb = (width < 769) ? 1 : 0;
        } else {
                geo->vtc  = 0;
                geo->comb = 0;
        }
}

static void
bttv_apply_geo(struct bttv *btv, struct bttv_geometry *geo, int odd)
{
        int off = odd ? 0x80 : 0x00;

        if (geo->comb)
                btor(BT848_VSCALE_COMB, BT848_E_VSCALE_HI+off);
        else
                btand(~BT848_VSCALE_COMB, BT848_E_VSCALE_HI+off);

        btwrite(geo->vtc,             BT848_E_VTC+off);
        btwrite(geo->hscale >> 8,     BT848_E_HSCALE_HI+off);
        btwrite(geo->hscale & 0xff,   BT848_E_HSCALE_LO+off);
        btaor((geo->vscale>>8), 0xe0, BT848_E_VSCALE_HI+off);
        btwrite(geo->vscale & 0xff,   BT848_E_VSCALE_LO+off);
        btwrite(geo->width & 0xff,    BT848_E_HACTIVE_LO+off);
        btwrite(geo->hdelay & 0xff,   BT848_E_HDELAY_LO+off);
        btwrite(geo->sheight & 0xff,  BT848_E_VACTIVE_LO+off);
        btwrite(geo->vdelay & 0xff,   BT848_E_VDELAY_LO+off);
        btwrite(geo->crop,            BT848_E_CROP+off);
        btwrite(geo->vtotal>>8,       BT848_VTOTAL_HI);
        btwrite(geo->vtotal & 0xff,   BT848_VTOTAL_LO);
}

/* ---------------------------------------------------------- */
/* risc group / risc main loop / dma management               */

static void bttv_set_risc_status(struct bttv *btv)
{
        unsigned long cmd = BT848_RISC_JUMP;
        if (btv->loop_irq) {
                cmd |= BT848_RISC_IRQ;
                cmd |= (btv->loop_irq  & 0x0f) << 16;
                cmd |= (~btv->loop_irq & 0x0f) << 20;
        }
        btv->main.cpu[RISC_SLOT_LOOP] = cpu_to_le32(cmd);
}

static void bttv_set_irq_timer(struct bttv *btv)
{
        if (btv->curr.frame_irq || btv->loop_irq || btv->cvbi)
                mod_timer(&btv->timeout, jiffies + BTTV_TIMEOUT);
        else
                timer_delete(&btv->timeout);
}

static int bttv_set_capture_control(struct bttv *btv, int start_capture)
{
        int capctl = 0;

        if (btv->curr.top || btv->curr.bottom)
                capctl = BT848_CAP_CTL_CAPTURE_ODD |
                         BT848_CAP_CTL_CAPTURE_EVEN;

        if (btv->cvbi)
                capctl |= BT848_CAP_CTL_CAPTURE_VBI_ODD |
                          BT848_CAP_CTL_CAPTURE_VBI_EVEN;

        capctl |= start_capture;

        btaor(capctl, ~0x0f, BT848_CAP_CTL);

        return capctl;
}

static void bttv_start_dma(struct bttv *btv)
{
        if (btv->dma_on)
                return;
        btwrite(btv->main.dma, BT848_RISC_STRT_ADD);
        btor(BT848_GPIO_DMA_CTL_RISC_ENABLE | BT848_GPIO_DMA_CTL_FIFO_ENABLE,
             BT848_GPIO_DMA_CTL);
        btv->dma_on = 1;
}

static void bttv_stop_dma(struct bttv *btv)
{
        if (!btv->dma_on)
                return;
        btand(~(BT848_GPIO_DMA_CTL_RISC_ENABLE |
                BT848_GPIO_DMA_CTL_FIFO_ENABLE), BT848_GPIO_DMA_CTL);
        btv->dma_on = 0;
}

void bttv_set_dma(struct bttv *btv, int start_capture)
{
        int capctl = 0;

        bttv_set_risc_status(btv);
        bttv_set_irq_timer(btv);
        capctl = bttv_set_capture_control(btv, start_capture);

        if (capctl)
                bttv_start_dma(btv);
        else
                bttv_stop_dma(btv);

        d2printk("%d: capctl=%x lirq=%d top=%08llx/%08llx even=%08llx/%08llx\n",
                 btv->c.nr,capctl,btv->loop_irq,
                 btv->cvbi         ? (unsigned long long)btv->cvbi->top.dma            : 0,
                 btv->curr.top     ? (unsigned long long)btv->curr.top->top.dma        : 0,
                 btv->cvbi         ? (unsigned long long)btv->cvbi->bottom.dma         : 0,
                 btv->curr.bottom  ? (unsigned long long)btv->curr.bottom->bottom.dma  : 0);
}

int
bttv_risc_init_main(struct bttv *btv)
{
        int rc;

        if ((rc = btcx_riscmem_alloc(btv->c.pci,&btv->main,PAGE_SIZE)) < 0)
                return rc;
        dprintk("%d: risc main @ %08llx\n",
                btv->c.nr, (unsigned long long)btv->main.dma);

        btv->main.cpu[0] = cpu_to_le32(BT848_RISC_SYNC | BT848_RISC_RESYNC |
                                       BT848_FIFO_STATUS_VRE);
        btv->main.cpu[1] = cpu_to_le32(0);
        btv->main.cpu[2] = cpu_to_le32(BT848_RISC_JUMP);
        btv->main.cpu[3] = cpu_to_le32(btv->main.dma + (4<<2));

        /* top field */
        btv->main.cpu[4] = cpu_to_le32(BT848_RISC_JUMP);
        btv->main.cpu[5] = cpu_to_le32(btv->main.dma + (6<<2));
        btv->main.cpu[6] = cpu_to_le32(BT848_RISC_JUMP);
        btv->main.cpu[7] = cpu_to_le32(btv->main.dma + (8<<2));

        btv->main.cpu[8] = cpu_to_le32(BT848_RISC_SYNC | BT848_RISC_RESYNC |
                                       BT848_FIFO_STATUS_VRO);
        btv->main.cpu[9] = cpu_to_le32(0);

        /* bottom field */
        btv->main.cpu[10] = cpu_to_le32(BT848_RISC_JUMP);
        btv->main.cpu[11] = cpu_to_le32(btv->main.dma + (12<<2));
        btv->main.cpu[12] = cpu_to_le32(BT848_RISC_JUMP);
        btv->main.cpu[13] = cpu_to_le32(btv->main.dma + (14<<2));

        /* jump back to top field */
        btv->main.cpu[14] = cpu_to_le32(BT848_RISC_JUMP);
        btv->main.cpu[15] = cpu_to_le32(btv->main.dma + (0<<2));

        return 0;
}

int
bttv_risc_hook(struct bttv *btv, int slot, struct btcx_riscmem *risc,
               int irqflags)
{
        unsigned long cmd;
        unsigned long next = btv->main.dma + ((slot+2) << 2);

        if (NULL == risc) {
                d2printk("%d: risc=%p slot[%d]=NULL\n", btv->c.nr, risc, slot);
                btv->main.cpu[slot+1] = cpu_to_le32(next);
        } else {
                d2printk("%d: risc=%p slot[%d]=%08llx irq=%d\n",
                         btv->c.nr, risc, slot,
                         (unsigned long long)risc->dma, irqflags);
                cmd = BT848_RISC_JUMP;
                if (irqflags) {
                        cmd |= BT848_RISC_IRQ;
                        cmd |= (irqflags  & 0x0f) << 16;
                        cmd |= (~irqflags & 0x0f) << 20;
                }
                risc->jmp[0] = cpu_to_le32(cmd);
                risc->jmp[1] = cpu_to_le32(next);
                btv->main.cpu[slot+1] = cpu_to_le32(risc->dma);
        }
        return 0;
}

int bttv_buffer_risc_vbi(struct bttv *btv, struct bttv_buffer *buf)
{
        int r = 0;
        unsigned int offset;
        unsigned int bpl = 2044; /* max. vbipack */
        unsigned int padding = VBI_BPL - bpl;
        unsigned int skip_lines0 = 0;
        unsigned int skip_lines1 = 0;
        unsigned int min_vdelay = MIN_VDELAY;

        const struct bttv_tvnorm *tvnorm = btv->vbi_fmt.tvnorm;
        struct sg_table *sgt = vb2_dma_sg_plane_desc(&buf->vbuf.vb2_buf, 0);
        struct scatterlist *list = sgt->sgl;

        if (btv->vbi_fmt.fmt.count[0] > 0)
                skip_lines0 = max(0, (btv->vbi_fmt.fmt.start[0] -
                                        tvnorm->vbistart[0]));
        if (btv->vbi_fmt.fmt.count[1] > 0)
                skip_lines1 = max(0, (btv->vbi_fmt.fmt.start[1] -
                                        tvnorm->vbistart[1]));

        if (btv->vbi_fmt.fmt.count[0] > 0) {
                r = bttv_risc_packed(btv, &buf->top, list, 0, bpl, padding,
                                     skip_lines0, btv->vbi_fmt.fmt.count[0]);
                if (r)
                        return r;
        }

        if (btv->vbi_fmt.fmt.count[1] > 0) {
                offset = btv->vbi_fmt.fmt.count[0] * VBI_BPL;
                r = bttv_risc_packed(btv, &buf->bottom, list, offset, bpl,
                                     padding, skip_lines1,
                                     btv->vbi_fmt.fmt.count[1]);
                if (r)
                        return r;
        }

        if (btv->vbi_fmt.end >= tvnorm->cropcap.bounds.top)
                min_vdelay += btv->vbi_fmt.end - tvnorm->cropcap.bounds.top;

        /* For bttv_buffer_activate_vbi(). */
        buf->geo.vdelay = min_vdelay;

        return r;
}

int
bttv_buffer_activate_vbi(struct bttv *btv,
                         struct bttv_buffer *vbi)
{
        struct btcx_riscmem *top;
        struct btcx_riscmem *bottom;
        int top_irq_flags;
        int bottom_irq_flags;

        top = NULL;
        bottom = NULL;
        top_irq_flags = 0;
        bottom_irq_flags = 0;

        if (vbi) {
                unsigned int crop, vdelay;

                list_del(&vbi->list);

                /* VDELAY is start of video, end of VBI capturing. */
                crop = btread(BT848_E_CROP);
                vdelay = btread(BT848_E_VDELAY_LO) + ((crop & 0xc0) << 2);

                if (vbi->geo.vdelay > vdelay) {
                        vdelay = vbi->geo.vdelay & 0xfe;
                        crop = (crop & 0x3f) | ((vbi->geo.vdelay >> 2) & 0xc0);

                        btwrite(vdelay, BT848_E_VDELAY_LO);
                        btwrite(crop,   BT848_E_CROP);
                        btwrite(vdelay, BT848_O_VDELAY_LO);
                        btwrite(crop,   BT848_O_CROP);
                }

                if (btv->vbi_count[0] > 0) {
                        top = &vbi->top;
                        top_irq_flags = 4;
                }

                if (btv->vbi_count[1] > 0) {
                        top_irq_flags = 0;
                        bottom = &vbi->bottom;
                        bottom_irq_flags = 4;
                }
        }

        bttv_risc_hook(btv, RISC_SLOT_O_VBI, top, top_irq_flags);
        bttv_risc_hook(btv, RISC_SLOT_E_VBI, bottom, bottom_irq_flags);

        return 0;
}

int
bttv_buffer_activate_video(struct bttv *btv,
                           struct bttv_buffer_set *set)
{
        /* video capture */
        if (NULL != set->top  &&  NULL != set->bottom) {
                if (set->top == set->bottom) {
                        if (set->top->list.next)
                                list_del(&set->top->list);
                } else {
                        if (set->top->list.next)
                                list_del(&set->top->list);
                        if (set->bottom->list.next)
                                list_del(&set->bottom->list);
                }
                bttv_apply_geo(btv, &set->top->geo, 1);
                bttv_apply_geo(btv, &set->bottom->geo,0);
                bttv_risc_hook(btv, RISC_SLOT_O_FIELD, &set->top->top,
                               set->top_irq);
                bttv_risc_hook(btv, RISC_SLOT_E_FIELD, &set->bottom->bottom,
                               set->frame_irq);
                btaor((set->top->btformat & 0xf0) | (set->bottom->btformat & 0x0f),
                      ~0xff, BT848_COLOR_FMT);
                btaor((set->top->btswap & 0x0a) | (set->bottom->btswap & 0x05),
                      ~0x0f, BT848_COLOR_CTL);
        } else if (NULL != set->top) {
                if (set->top->list.next)
                        list_del(&set->top->list);
                bttv_apply_geo(btv, &set->top->geo,1);
                bttv_apply_geo(btv, &set->top->geo,0);
                bttv_risc_hook(btv, RISC_SLOT_O_FIELD, &set->top->top,
                               set->frame_irq);
                bttv_risc_hook(btv, RISC_SLOT_E_FIELD, NULL,           0);
                btaor(set->top->btformat & 0xff, ~0xff, BT848_COLOR_FMT);
                btaor(set->top->btswap & 0x0f,   ~0x0f, BT848_COLOR_CTL);
        } else if (NULL != set->bottom) {
                if (set->bottom->list.next)
                        list_del(&set->bottom->list);
                bttv_apply_geo(btv, &set->bottom->geo,1);
                bttv_apply_geo(btv, &set->bottom->geo,0);
                bttv_risc_hook(btv, RISC_SLOT_O_FIELD, NULL, 0);
                bttv_risc_hook(btv, RISC_SLOT_E_FIELD, &set->bottom->bottom,
                               set->frame_irq);
                btaor(set->bottom->btformat & 0xff, ~0xff, BT848_COLOR_FMT);
                btaor(set->bottom->btswap & 0x0f,   ~0x0f, BT848_COLOR_CTL);
        } else {
                bttv_risc_hook(btv, RISC_SLOT_O_FIELD, NULL, 0);
                bttv_risc_hook(btv, RISC_SLOT_E_FIELD, NULL, 0);
        }
        return 0;
}

/* ---------------------------------------------------------- */

/* calculate geometry, build risc code */
int
bttv_buffer_risc(struct bttv *btv, struct bttv_buffer *buf)
{
        int r = 0;
        const struct bttv_tvnorm *tvnorm = bttv_tvnorms + btv->tvnorm;
        struct sg_table *sgt = vb2_dma_sg_plane_desc(&buf->vbuf.vb2_buf, 0);
        struct scatterlist *list = sgt->sgl;
        unsigned long size = (btv->fmt->depth * btv->width * btv->height) >> 3;

        /* packed pixel modes */
        if (btv->fmt->flags & FORMAT_FLAGS_PACKED) {
                int bpl = (btv->fmt->depth >> 3) * btv->width;
                int bpf = bpl * (btv->height >> 1);

                bttv_calc_geo(btv, &buf->geo, btv->width, btv->height,
                              V4L2_FIELD_HAS_BOTH(buf->vbuf.field), tvnorm,
                              &btv->crop[!!btv->do_crop].rect);
                switch (buf->vbuf.field) {
                case V4L2_FIELD_TOP:
                        r = bttv_risc_packed(btv, &buf->top, list, 0, bpl, 0,
                                             0, btv->height);
                        break;
                case V4L2_FIELD_BOTTOM:
                        r = bttv_risc_packed(btv, &buf->bottom, list, 0, bpl,
                                             0, 0, btv->height);
                        break;
                case V4L2_FIELD_INTERLACED:
                        r = bttv_risc_packed(btv, &buf->top, list, 0, bpl,
                                             bpl, 0, btv->height >> 1);
                        r = bttv_risc_packed(btv, &buf->bottom, list, bpl,
                                             bpl, bpl, 0, btv->height >> 1);
                        break;
                case V4L2_FIELD_SEQ_TB:
                        r = bttv_risc_packed(btv, &buf->top, list, 0, bpl, 0,
                                             0, btv->height >> 1);
                        r = bttv_risc_packed(btv, &buf->bottom, list, bpf,
                                             bpl, 0, 0, btv->height >> 1);
                        break;
                default:
                        WARN_ON(1);
                        return -EINVAL;
                }
        }
        /* planar modes */
        if (btv->fmt->flags & FORMAT_FLAGS_PLANAR) {
                int uoffset, voffset;
                int ypadding, cpadding, lines;

                /* calculate chroma offsets */
                uoffset = btv->width * btv->height;
                voffset = btv->width * btv->height;
                if (btv->fmt->flags & FORMAT_FLAGS_CrCb) {
                        /* Y-Cr-Cb plane order */
                        uoffset >>= btv->fmt->hshift;
                        uoffset >>= btv->fmt->vshift;
                        uoffset  += voffset;
                } else {
                        /* Y-Cb-Cr plane order */
                        voffset >>= btv->fmt->hshift;
                        voffset >>= btv->fmt->vshift;
                        voffset  += uoffset;
                }
                switch (buf->vbuf.field) {
                case V4L2_FIELD_TOP:
                        bttv_calc_geo(btv, &buf->geo, btv->width, btv->height,
                                      0, tvnorm,
                                      &btv->crop[!!btv->do_crop].rect);
                        r = bttv_risc_planar(btv, &buf->top, list, 0,
                                             btv->width, 0, btv->height,
                                             uoffset, voffset,
                                             btv->fmt->hshift,
                                             btv->fmt->vshift, 0);
                        break;
                case V4L2_FIELD_BOTTOM:
                        bttv_calc_geo(btv, &buf->geo, btv->width, btv->height,
                                      0, tvnorm,
                                      &btv->crop[!!btv->do_crop].rect);
                        r = bttv_risc_planar(btv, &buf->bottom, list, 0,
                                             btv->width, 0, btv->height,
                                             uoffset, voffset,
                                             btv->fmt->hshift,
                                             btv->fmt->vshift, 0);
                        break;
                case V4L2_FIELD_INTERLACED:
                        bttv_calc_geo(btv, &buf->geo, btv->width, btv->height,
                                      1, tvnorm,
                                      &btv->crop[!!btv->do_crop].rect);
                        lines = btv->height >> 1;
                        ypadding = btv->width;
                        cpadding = btv->width >> btv->fmt->hshift;
                        r = bttv_risc_planar(btv, &buf->top, list, 0,
                                             btv->width, ypadding, lines,
                                             uoffset, voffset,
                                             btv->fmt->hshift,
                                             btv->fmt->vshift, cpadding);

                        r = bttv_risc_planar(btv, &buf->bottom, list,
                                             ypadding, btv->width, ypadding,
                                             lines,  uoffset + cpadding,
                                             voffset + cpadding,
                                             btv->fmt->hshift,
                                             btv->fmt->vshift, cpadding);
                        break;
                case V4L2_FIELD_SEQ_TB:
                        bttv_calc_geo(btv, &buf->geo, btv->width, btv->height,
                                      1, tvnorm,
                                      &btv->crop[!!btv->do_crop].rect);
                        lines = btv->height >> 1;
                        ypadding = btv->width;
                        cpadding = btv->width >> btv->fmt->hshift;
                        r = bttv_risc_planar(btv, &buf->top, list, 0,
                                             btv->width, 0, lines,
                                             uoffset >> 1, voffset >> 1,
                                             btv->fmt->hshift,
                                             btv->fmt->vshift, 0);
                        r = bttv_risc_planar(btv, &buf->bottom, list,
                                             lines * ypadding,
                                             btv->width, 0, lines,
                                             lines * ypadding + (uoffset >> 1),
                                             lines * ypadding + (voffset >> 1),
                                             btv->fmt->hshift,
                                             btv->fmt->vshift, 0);
                        break;
                default:
                        WARN_ON(1);
                        return -EINVAL;
                }
        }
        /* raw data */
        if (btv->fmt->flags & FORMAT_FLAGS_RAW) {
                /* build risc code */
                buf->vbuf.field = V4L2_FIELD_SEQ_TB;
                bttv_calc_geo(btv, &buf->geo, tvnorm->swidth, tvnorm->sheight,
                              1, tvnorm, &btv->crop[!!btv->do_crop].rect);
                r = bttv_risc_packed(btv, &buf->top, list, 0, RAW_BPL, 0, 0,
                                     RAW_LINES);
                r = bttv_risc_packed(btv, &buf->bottom, list, size / 2,
                                     RAW_BPL, 0, 0, RAW_LINES);
        }

        /* copy format info */
        buf->btformat = btv->fmt->btformat;
        buf->btswap   = btv->fmt->btswap;

        return r;
}