root/sys/dev/ic/ssdfb.c
/* $NetBSD: ssdfb.c,v 1.22 2021/08/21 17:50:02 tnn Exp $ */

/*
 * Copyright (c) 2019 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Tobias Nygren.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: ssdfb.c,v 1.22 2021/08/21 17:50:02 tnn Exp $");

#include "opt_ddb.h"

#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/conf.h>
#include <sys/condvar.h>
#include <sys/kmem.h>
#include <sys/kthread.h>

#include <uvm/uvm_device.h>
#include <uvm/uvm_extern.h>
#ifdef pmap_is_modified
#include <uvm/uvm_page.h>
#endif

#include <dev/wscons/wsdisplayvar.h>
#include <dev/rasops/rasops.h>
#include <dev/ic/ssdfbvar.h>

#if defined(DDB)
#include <machine/db_machdep.h>
#include <ddb/db_extern.h>
#endif

/* userland interface */
static int      ssdfb_ioctl(void *, void *, u_long, void *, int, struct lwp *);
static paddr_t  ssdfb_mmap(void *, void *, off_t, int);

/* wscons screen management */
static int      ssdfb_alloc_screen(void *, const struct wsscreen_descr *,
                                   void **, int *, int *, long *);
static void     ssdfb_free_screen(void *, void *);
static int      ssdfb_show_screen(void *, void *, int,
                                  void (*cb) (void *, int, int), void *);

/* rasops hooks */
static void     ssdfb_putchar(void *, int, int, u_int, long);
static void     ssdfb_copycols(void *, int, int, int, int);
static void     ssdfb_erasecols(void *, int, int, int, long);
static void     ssdfb_copyrows(void *, int, int, int);
static void     ssdfb_eraserows(void *, int, int, long);
static void     ssdfb_cursor(void *, int, int, int);

/* hardware interface */
static int      ssdfb_init_ssd1306(struct ssdfb_softc *);
static int      ssdfb_init_ssd1322(struct ssdfb_softc *);
static int      ssdfb_init_ssd1353(struct ssdfb_softc *);
static int      ssdfb_set_contrast(struct ssdfb_softc *, uint8_t, bool);
static int      ssdfb_set_display_on(struct ssdfb_softc *, bool, bool);
static int      ssdfb_set_mode(struct ssdfb_softc *, u_int);

/* frame buffer damage tracking and synchronization */
static void     ssdfb_udv_attach(struct ssdfb_softc *sc);
static bool     ssdfb_is_modified(struct ssdfb_softc *sc);
static bool     ssdfb_clear_modify(struct ssdfb_softc *sc);
static void     ssdfb_damage(struct ssdfb_softc *);
static void     ssdfb_thread(void *);
static void     ssdfb_set_usepoll(struct ssdfb_softc *, bool);
static int      ssdfb_sync(struct ssdfb_softc *, bool);
static int      ssdfb_sync_ssd1306(struct ssdfb_softc *, bool);
static int      ssdfb_sync_ssd1322(struct ssdfb_softc *, bool);
static int      ssdfb_sync_ssd1353(struct ssdfb_softc *, bool);
static uint64_t ssdfb_transpose_block(uint8_t *, size_t);

/* misc helpers */
static const struct ssdfb_product *
                ssdfb_lookup_product(ssdfb_product_id_t);
static int      ssdfb_pick_font(int *, struct wsdisplay_font **);
static void     ssdfb_clear_screen(struct ssdfb_softc *);
#if defined(DDB)
static void     ssdfb_ddb_trap_callback(int);
#endif

static const char *ssdfb_controller_names[] = {
        [SSDFB_CONTROLLER_UNKNOWN] =    "unknown",
        [SSDFB_CONTROLLER_SSD1306] =    "Solomon Systech SSD1306",
        [SSDFB_CONTROLLER_SH1106] =     "Sino Wealth SH1106",
        [SSDFB_CONTROLLER_SSD1322] =    "Solomon Systech SSD1322",
        [SSDFB_CONTROLLER_SSD1353] =    "Solomon Systech SSD1353"
};

/*
 * Display module assemblies supported by this driver.
 */
static const struct ssdfb_product ssdfb_products[] = {
        {
                .p_product_id =         SSDFB_PRODUCT_SSD1306_GENERIC,
                .p_controller_id =      SSDFB_CONTROLLER_SSD1306,
                .p_name =               "generic",
                .p_width =              128,
                .p_height =             64,
                .p_bits_per_pixel =     1,
                .p_panel_shift =        0,
                .p_fosc =               0x8,
                .p_fosc_div =           0,
                .p_precharge =          0x1,
                .p_discharge =          0xf,
                .p_compin_cfg =         SSDFB_COM_PINS_A1_MASK
                                        | SSDFB_COM_PINS_ALTERNATIVE_MASK,
                .p_vcomh_deselect_level = SSD1306_VCOMH_DESELECT_LEVEL_0_77_VCC,
                .p_default_contrast =   0x7f,
                .p_multiplex_ratio =    0x3f,
                .p_init =               ssdfb_init_ssd1306,
                .p_sync =               ssdfb_sync_ssd1306
        },
        {
                .p_product_id =         SSDFB_PRODUCT_SH1106_GENERIC,
                .p_controller_id =      SSDFB_CONTROLLER_SH1106,
                .p_name =               "generic",
                .p_width =              128,
                .p_height =             64,
                .p_bits_per_pixel =     1,
                .p_panel_shift =        2,
                .p_fosc =               0x5,
                .p_fosc_div =           0,
                .p_precharge =          0x2,
                .p_discharge =          0x2,
                .p_compin_cfg =         SSDFB_COM_PINS_A1_MASK
                                        | SSDFB_COM_PINS_ALTERNATIVE_MASK,
                .p_vcomh_deselect_level = SH1106_VCOMH_DESELECT_LEVEL_DEFAULT,
                .p_default_contrast =   0x80,
                .p_multiplex_ratio =    0x3f,
                .p_init =               ssdfb_init_ssd1306,
                .p_sync =               ssdfb_sync_ssd1306
        },
        {
                .p_product_id =         SSDFB_PRODUCT_ADAFRUIT_938,
                .p_controller_id =      SSDFB_CONTROLLER_SSD1306,
                .p_name =               "Adafruit Industries, LLC product 938",
                .p_width =              128,
                .p_height =             64,
                .p_bits_per_pixel =     1,
                .p_panel_shift =        0,
                .p_fosc =               0x8,
                .p_fosc_div =           0,
                .p_precharge =          0x1,
                .p_discharge =          0xf,
                .p_compin_cfg =         0x12,
                .p_vcomh_deselect_level = 0x40,
                .p_default_contrast =   0x8f,
                .p_multiplex_ratio =    0x3f,
                .p_init =               ssdfb_init_ssd1306,
                .p_sync =               ssdfb_sync_ssd1306
        },
        {
                .p_product_id =         SSDFB_PRODUCT_ADAFRUIT_931,
                .p_controller_id =      SSDFB_CONTROLLER_SSD1306,
                .p_name =               "Adafruit Industries, LLC product 931",
                .p_width =              128,
                .p_height =             32,
                .p_bits_per_pixel =     1,
                .p_panel_shift =        0,
                .p_fosc =               0x8,
                .p_fosc_div =           0,
                .p_precharge =          0x1,
                .p_discharge =          0xf,
                .p_compin_cfg =         0x2,
                .p_vcomh_deselect_level = 0x40,
                .p_default_contrast =   0x8f,
                .p_multiplex_ratio =    0x1f,
                .p_init =               ssdfb_init_ssd1306,
                .p_sync =               ssdfb_sync_ssd1306
        },
        {
                .p_product_id =         SSDFB_PRODUCT_SSD1322_GENERIC,
                .p_controller_id =      SSDFB_CONTROLLER_SSD1322,
                .p_name =               "generic",
                .p_width =              256,
                .p_height =             64,
                .p_bits_per_pixel =     4,
                .p_panel_shift =        28,
                .p_vcomh_deselect_level = SSD1322_DEFAULT_VCOMH,
                .p_fosc =               SSD1322_DEFAULT_FREQUENCY,
                .p_fosc_div =           SSD1322_DEFAULT_DIVIDER,
                .p_default_contrast =   SSD1322_DEFAULT_CONTRAST_CURRENT,
                .p_multiplex_ratio =    0x3f,
                .p_init =               ssdfb_init_ssd1322,
                .p_sync =               ssdfb_sync_ssd1322
        },
        {
                .p_product_id =         SSDFB_PRODUCT_SSD1353_GENERIC,
                .p_controller_id =      SSDFB_CONTROLLER_SSD1353,
                .p_name =               "generic",
                .p_width =              160,
                .p_height =             132,
                .p_bits_per_pixel =     32,
                .p_rgb =                true,
                .p_panel_shift =        0,
                .p_compin_cfg = SSD1353_REMAP_RGB | SSD1353_REMAP_SPLIT_ODD_EVEN
                    | __SHIFTIN(2, SSD1353_REMAP_PIXEL_FORMAT_MASK),
                .p_vcomh_deselect_level = SSD1353_DEFAULT_VCOMH,
                .p_fosc =               SSD1353_DEFAULT_FREQUENCY,
                .p_fosc_div =           SSD1353_DEFAULT_DIVIDER,
                .p_default_contrast =   SSD1353_DEFAULT_CONTRAST_CONTROL,
                .p_multiplex_ratio =    0x83,
                .p_init =               ssdfb_init_ssd1353,
                .p_sync =               ssdfb_sync_ssd1353
        },
        {
                .p_product_id =         SSDFB_PRODUCT_DEP_160128A_RGB,
                .p_controller_id =      SSDFB_CONTROLLER_SSD1353,
                .p_name =               "Display Elektronik GmbH DEP 160128A(1)-RGB",
                .p_width =              160,
                .p_height =             128,
                .p_bits_per_pixel =     32,
                .p_rgb =                true,
                .p_panel_shift =        0,
                .p_compin_cfg = SSD1353_REMAP_RGB | SSD1353_REMAP_SPLIT_ODD_EVEN
                    | __SHIFTIN(2, SSD1353_REMAP_PIXEL_FORMAT_MASK),
                .p_vcomh_deselect_level = SSD1353_DEFAULT_VCOMH,
                .p_fosc =               SSD1353_DEFAULT_FREQUENCY,
                .p_fosc_div =           SSD1353_DEFAULT_DIVIDER,
                .p_default_contrast =   SSD1353_DEFAULT_CONTRAST_CONTROL,
                .p_multiplex_ratio =    0x83,
                .p_init =               ssdfb_init_ssd1353,
                .p_sync =               ssdfb_sync_ssd1353
        }
};

static const struct wsdisplay_accessops ssdfb_accessops = {
        .ioctl =        ssdfb_ioctl,
        .mmap =         ssdfb_mmap,
        .alloc_screen = ssdfb_alloc_screen,
        .free_screen =  ssdfb_free_screen,
        .show_screen =  ssdfb_show_screen
};

#define SSDFB_CMD1(c) do { cmd[0] = (c); error = sc->sc_cmd(sc->sc_cookie, cmd, 1, usepoll); } while(0)
#define SSDFB_CMD2(c, a) do { cmd[0] = (c); cmd[1] = (a); error = sc->sc_cmd(sc->sc_cookie, cmd, 2, usepoll); } while(0)
#define SSDFB_CMD3(c, a, b) do { cmd[0] = (c); cmd[1] = (a); cmd[2] = (b); error = sc->sc_cmd(sc->sc_cookie, cmd, 3, usepoll); } while(0)

void
ssdfb_attach(struct ssdfb_softc *sc, int flags)
{
        struct wsemuldisplaydev_attach_args aa;
        struct rasops_info *ri = &sc->sc_ri;
        int error = 0;
        long defattr;
        const struct ssdfb_product *p;
        int kt_flags;

        p = ssdfb_lookup_product(flags & SSDFB_ATTACH_FLAG_PRODUCT_MASK);
        if (p == NULL) {
                aprint_error(": unknown display assembly\n");
                return;
        }
        sc->sc_p = p;

        aprint_naive("\n");
        aprint_normal(": %s (%s)\n",
            ssdfb_controller_names[p->p_controller_id],
            p->p_name);

        sc->sc_mode = WSDISPLAYIO_MODE_EMUL;
        sc->sc_is_console = flags & SSDFB_ATTACH_FLAG_CONSOLE ? true : false;
        sc->sc_inverse = flags & SSDFB_ATTACH_FLAG_INVERSE ? true : false;
        sc->sc_upsidedown = flags & SSDFB_ATTACH_FLAG_UPSIDEDOWN ? true : false;
        sc->sc_backoff = 1;
        sc->sc_contrast = sc->sc_p->p_default_contrast;
        sc->sc_gddram_len = sc->sc_p->p_width * sc->sc_p->p_height
            * sc->sc_p->p_bits_per_pixel / 8;
        sc->sc_gddram = kmem_alloc(sc->sc_gddram_len, KM_SLEEP);
        if (sc->sc_gddram == NULL)
                goto out;

        aprint_normal_dev(sc->sc_dev, "%dx%d%s\n", sc->sc_p->p_width,
            sc->sc_p->p_height, sc->sc_is_console ? ", console" : "");

        /*
         * Initialize rasops. The native depth is 1-bit monochrome and we
         * support this in text emul mode via rasops1. But modern Xorg
         * userland has many rendering glitches when running with 1-bit depth
         * so to better support this use case we instead declare ourselves as
         * an 8-bit display with a two entry constant color map.
         */
        error = ssdfb_pick_font(&sc->sc_fontcookie, &sc->sc_font);
        if (error) {
                aprint_error_dev(sc->sc_dev, "no font\n");
                goto out;
        }
#ifdef SSDFB_USE_NATIVE_DEPTH
        ri->ri_depth = sc->sc_p->p_bits_per_pixel;
#else
        if (sc->sc_p->p_rgb && sc->sc_p->p_bits_per_pixel == 32) {
                ri->ri_depth = sc->sc_p->p_bits_per_pixel;
                ri->ri_rnum = 8;
                ri->ri_gnum = 8;
                ri->ri_bnum = 8;
#if _BYTE_ORDER == _LITTLE_ENDIAN
                ri->ri_rpos = 0;
                ri->ri_gpos = 8;
                ri->ri_bpos = 16;
#else
                ri->ri_rpos = 24;
                ri->ri_gpos = 16;
                ri->ri_bpos = 8;
#endif
        } else {
                ri->ri_depth = 8;
        }
#endif
        ri->ri_font =   sc->sc_font;
        ri->ri_width =  sc->sc_p->p_width;
        ri->ri_height = sc->sc_p->p_height;
        ri->ri_stride = ri->ri_width * ri->ri_depth / 8;
        ri->ri_hw =     sc;
        ri->ri_flg =    RI_FULLCLEAR;
        if (!sc->sc_p->p_rgb) {
                ri->ri_flg |= RI_FORCEMONO;
        }
        sc->sc_ri_bits_len = round_page(ri->ri_stride * ri->ri_height);
        ri->ri_bits     = (u_char *)uvm_km_alloc(kernel_map, sc->sc_ri_bits_len,
                                                 0, UVM_KMF_WIRED);
        if (ri->ri_bits == NULL)
                goto out;

        error = rasops_init(ri,
            sc->sc_p->p_height / sc->sc_font->fontheight,
            sc->sc_p->p_width  / sc->sc_font->fontwidth);
        if (error)
                goto out;

        if (!sc->sc_p->p_rgb) {
                ri->ri_caps &= ~WSSCREEN_WSCOLORS;
        }

        /*
         * Save original emul ops & insert our damage notification hooks.
         */
        sc->sc_orig_riops =     ri->ri_ops;
        ri->ri_ops.putchar =    ssdfb_putchar;
        ri->ri_ops.copycols =   ssdfb_copycols;
        ri->ri_ops.erasecols =  ssdfb_erasecols;
        ri->ri_ops.copyrows =   ssdfb_copyrows;
        ri->ri_ops.eraserows =  ssdfb_eraserows;
        ri->ri_ops.cursor =     ssdfb_cursor;

        /*
         * Set up the screen.
         */
        sc->sc_screen_descr = (struct wsscreen_descr){
                .name =         "default",
                .ncols =        ri->ri_cols,
                .nrows =        ri->ri_rows,
                .textops =      &ri->ri_ops,
                .fontwidth =    ri->ri_font->fontwidth,
                .fontheight =   ri->ri_font->fontheight,
                .capabilities = ri->ri_caps
        };
        sc->sc_screens[0] = &sc->sc_screen_descr;
        sc->sc_screenlist = (struct wsscreen_list){
                .nscreens =     1,
                .screens =      sc->sc_screens
        };

        /*
         * Initialize hardware.
         */
        error = p->p_init(sc);
        if (error)
                goto out;

        if (sc->sc_is_console)
                ssdfb_set_usepoll(sc, true);

        mutex_init(&sc->sc_cond_mtx, MUTEX_DEFAULT,
            ISSET(flags, SSDFB_ATTACH_FLAG_MPSAFE) ? IPL_SCHED : IPL_BIO);
        cv_init(&sc->sc_cond, "ssdfb");
        kt_flags = KTHREAD_MUSTJOIN;
        /* XXX spi(4) is not MPSAFE yet. */
        if (ISSET(flags, SSDFB_ATTACH_FLAG_MPSAFE))
                kt_flags |= KTHREAD_MPSAFE;
        error = kthread_create(PRI_SOFTCLOCK, kt_flags, NULL, ssdfb_thread, sc,
            &sc->sc_thread, "%s", device_xname(sc->sc_dev));
        if (error) {
                cv_destroy(&sc->sc_cond);
                mutex_destroy(&sc->sc_cond_mtx);
                goto out;
        }

        /*
         * Attach wsdisplay.
         */
        if (sc->sc_is_console) {
                (*ri->ri_ops.allocattr)(ri, 0, 0, 0, &defattr);
                wsdisplay_cnattach(&sc->sc_screen_descr, ri, 0, 0, defattr);
#if defined(DDB)
                db_trap_callback = ssdfb_ddb_trap_callback;
#endif
        }
        aa = (struct wsemuldisplaydev_attach_args){
                .console =      sc->sc_is_console,
                .scrdata =      &sc->sc_screenlist,
                .accessops =    &ssdfb_accessops,
                .accesscookie = sc
        };
        sc->sc_wsdisplay =
            config_found(sc->sc_dev, &aa, wsemuldisplaydevprint, CFARGS_NONE);

        return;
out:
        aprint_error_dev(sc->sc_dev, "attach failed: %d\n", error);
        if (sc->sc_gddram != NULL)
                kmem_free(sc->sc_gddram, sc->sc_gddram_len);
        if (ri->ri_bits != NULL)
                uvm_km_free(kernel_map, (vaddr_t)ri->ri_bits, sc->sc_ri_bits_len,
                    UVM_KMF_WIRED);
        if (sc->sc_fontcookie > 0)
                (void) wsfont_unlock(sc->sc_fontcookie);
}

int
ssdfb_detach(struct ssdfb_softc *sc)
{
        mutex_enter(&sc->sc_cond_mtx);
        sc->sc_detaching = true;
        cv_broadcast(&sc->sc_cond);
        mutex_exit(&sc->sc_cond_mtx);
        kthread_join(sc->sc_thread);

        if (sc->sc_uobj != NULL) {
                rw_enter(sc->sc_uobj->vmobjlock, RW_WRITER);
                sc->sc_uobj->uo_refs--;
                rw_exit(sc->sc_uobj->vmobjlock);
        }
        config_detach(sc->sc_wsdisplay, DETACH_FORCE);

        cv_destroy(&sc->sc_cond);
        mutex_destroy(&sc->sc_cond_mtx);
        uvm_km_free(kernel_map, (vaddr_t)sc->sc_ri.ri_bits, sc->sc_ri_bits_len,
            UVM_KMF_WIRED);
        kmem_free(sc->sc_gddram, sc->sc_gddram_len);
        (void) wsfont_unlock(sc->sc_fontcookie);
        return 0;
}

static int
ssdfb_ioctl(void *v, void *vs, u_long cmd, void *data, int flag, struct lwp *l)
{
        struct ssdfb_softc *sc = v;
        struct wsdisplay_param *wdp;
        struct wsdisplay_cmap *wc;
        u_char cmap[16];
        int cmaplen = 1 << sc->sc_p->p_bits_per_pixel;
        int i;
        struct wsdisplayio_fbinfo *fbi;
        int error;

        switch (cmd) {
        case WSDISPLAYIO_GTYPE:
                 *(u_int *)data = WSDISPLAY_TYPE_SSDFB;
                return 0;
        case WSDISPLAYIO_GINFO:
                *(struct wsdisplay_fbinfo *)data = (struct wsdisplay_fbinfo){
                        .width =        sc->sc_ri.ri_width,
                        .height =       sc->sc_ri.ri_height,
                        .depth =        sc->sc_ri.ri_depth,
                        .cmsize =       cmaplen
                };
                return 0;
        case WSDISPLAYIO_GET_FBINFO:
                fbi = (struct wsdisplayio_fbinfo *)data;
                error = wsdisplayio_get_fbinfo(&sc->sc_ri, fbi);
                if (!sc->sc_p->p_rgb) {
                        fbi->fbi_subtype.fbi_cmapinfo.cmap_entries = cmaplen;
                        /* fbi->fbi_pixeltype = WSFB_GREYSCALE */;
                }
                return error;
        case WSDISPLAYIO_LINEBYTES:
                *(u_int *)data = sc->sc_ri.ri_stride;
                return 0;
        case WSDISPLAYIO_GETPARAM:
                wdp = (struct wsdisplay_param *)data;
                if (wdp->param != WSDISPLAYIO_PARAM_CONTRAST)
                        return EINVAL;
                wdp->min = 0;
                wdp->max = 0xff;
                wdp->curval = sc->sc_contrast;
                return 0;
        case WSDISPLAYIO_SETPARAM:
                wdp = (struct wsdisplay_param *)data;
                if (wdp->param != WSDISPLAYIO_PARAM_CONTRAST)
                        return EINVAL;
                if (wdp->curval < 0 || wdp->curval > 0xff)
                        return EINVAL;
                return ssdfb_set_contrast(sc, wdp->curval, sc->sc_usepoll);
        case WSDISPLAYIO_GMODE:
                *(u_int *)data = sc->sc_mode;
                return 0;
        case WSDISPLAYIO_SMODE:
                return ssdfb_set_mode(sc, *(u_int *)data);
        case WSDISPLAYIO_GVIDEO:
                *(u_int *)data = sc->sc_display_on
                        ? WSDISPLAYIO_VIDEO_ON
                        : WSDISPLAYIO_VIDEO_OFF;
                return 0;
        case WSDISPLAYIO_SVIDEO:
                switch (*(u_int *)data) {
                case WSDISPLAYIO_VIDEO_ON:
                case WSDISPLAYIO_VIDEO_OFF:
                        break;
                default:
                        return EINVAL;
                }
                return ssdfb_set_display_on(sc,
                    *(u_int *)data == WSDISPLAYIO_VIDEO_ON ? true : false,
                    sc->sc_usepoll);
#if 0 /* don't let userland mess with polling yet */
        case WSDISPLAYIO_SET_POLLING:
                switch (*(u_int *)data) {
                case 0:
                case 1:
                        break;
                default:
                        return EINVAL;
                }
                mutex_enter(&sc->sc_cond_mtx);
                ssdfb_set_usepoll(sc, *(u_int *)data ? true : false);
                cv_broadcast(&sc->sc_cond);
                mutex_exit(&sc->sc_cond_mtx);
                return 0;
#endif
        case WSDISPLAYIO_GETCMAP:
                if (sc->sc_p->p_rgb)
                        return ENOTSUP;
                wc = (struct wsdisplay_cmap *)data;
                if (wc->index >= cmaplen ||
                    wc->count > cmaplen - wc->index)
                        return EINVAL;
                for(i = 0; i < cmaplen; i++) {
                        cmap[i] = 255 * i / (cmaplen - 1);
                }
                error = copyout(&cmap[wc->index], wc->red, wc->count);
                if (error)
                        return error;
                error = copyout(&cmap[wc->index], wc->green, wc->count);
                if (error)
                        return error;
                error = copyout(&cmap[wc->index], wc->blue, wc->count);
                return error;
        case WSDISPLAYIO_PUTCMAP:
                return ENODEV;
        }

        return EPASSTHROUGH;
}

static paddr_t
ssdfb_mmap(void *v, void *vs, off_t off, int prot)
{
        struct ssdfb_softc *sc = (struct ssdfb_softc *)v;
        struct rasops_info *ri = &sc->sc_ri;
        vaddr_t va_base = (vaddr_t)ri->ri_bits;
        paddr_t pa;

        if (off < 0 || off >= sc->sc_ri_bits_len || (off & PAGE_MASK) != 0)
                return -1;

        if (!pmap_extract(pmap_kernel(), va_base + off, &pa))
                return -1;

        return atop(pa);
}

static int
ssdfb_alloc_screen(void *v, const struct wsscreen_descr *descr, void **cookiep,
                   int *curxp, int *curyp, long *attrp)
{
        struct ssdfb_softc *sc = v;
        struct rasops_info *ri = &sc->sc_ri;

        if (sc->sc_nscreens > 0)
                return ENOMEM;

        ri->ri_ops.allocattr(ri, 0, 0, 0, attrp);
        *cookiep = &sc->sc_ri;
        *curxp = 0;
        *curyp = 0;
        sc->sc_nscreens++;

        return 0;
}

static void
ssdfb_free_screen(void *v, void *cookie)
{
        struct ssdfb_softc *sc = v;

        if (sc->sc_is_console)
                panic("ssdfb_free_screen: is console");

        sc->sc_nscreens--;
}

static int
ssdfb_show_screen(void *v, void *cookie, int waitok,
                  void (*cb) (void *, int, int), void *cb_arg)
{
        return 0;
}

static void
ssdfb_putchar(void *cookie, int row, int col, u_int c, long attr)
{
        struct rasops_info *ri = (struct rasops_info *)cookie;
        struct ssdfb_softc *sc = ri->ri_hw;

        sc->sc_orig_riops.putchar(cookie, row, col, c, attr);
        ssdfb_damage(sc);
}

static void
ssdfb_copycols(void *cookie, int row, int srccol, int dstcol, int ncols)
{
        struct rasops_info *ri = (struct rasops_info *)cookie;
        struct ssdfb_softc *sc = ri->ri_hw;

        sc->sc_orig_riops.copycols(cookie, row, srccol, dstcol, ncols);
        ssdfb_damage(sc);
}

static void
ssdfb_erasecols(void *cookie, int row, int startcol, int ncols, long fillattr)
{
        struct rasops_info *ri = (struct rasops_info *)cookie;
        struct ssdfb_softc *sc = ri->ri_hw;

        sc->sc_orig_riops.erasecols(cookie, row, startcol, ncols, fillattr);
        ssdfb_damage(sc);
}

static void
ssdfb_copyrows(void *cookie, int srcrow, int dstrow, int nrows)
{
        struct rasops_info *ri = (struct rasops_info *)cookie;
        struct ssdfb_softc *sc = ri->ri_hw;

        sc->sc_orig_riops.copyrows(cookie, srcrow, dstrow, nrows);
        ssdfb_damage(sc);
}

static void
ssdfb_eraserows(void *cookie, int row, int nrows, long fillattr)
{
        struct rasops_info *ri = (struct rasops_info *)cookie;
        struct ssdfb_softc *sc = ri->ri_hw;

        sc->sc_orig_riops.eraserows(cookie, row, nrows, fillattr);
        ssdfb_damage(sc);
}

static void
ssdfb_cursor(void *cookie, int on, int row, int col)
{
        struct rasops_info *ri = (struct rasops_info *)cookie;
        struct ssdfb_softc *sc = ri->ri_hw;

        sc->sc_orig_riops.cursor(cookie, on, row, col);
        ssdfb_damage(sc);
}

static int
ssdfb_init_ssd1306(struct ssdfb_softc *sc)
{
        int error;
        uint8_t cmd[2];
        bool usepoll = true;

        /*
         * Enter sleep.
         */
        SSDFB_CMD1(SSDFB_CMD_SET_DISPLAY_OFF);
        if (error)
                return error;
        SSDFB_CMD1(SSDFB_CMD_DEACTIVATE_SCROLL);
        if (error)
                return error;
        SSDFB_CMD1(SSDFB_CMD_ENTIRE_DISPLAY_OFF);
        if (error)
                return error;

        /*
         * Configure physical display panel layout.
         */
        SSDFB_CMD2(SSDFB_CMD_SET_MULTIPLEX_RATIO, sc->sc_p->p_multiplex_ratio);
        if (error)
                return error;
        SSDFB_CMD2(SSDFB_CMD_SET_DISPLAY_OFFSET, 0);
        if (error)
                return error;
        SSDFB_CMD1(SSDFB_CMD_SET_DISPLAY_START_LINE_BASE + 0x00);
        if (error)
                return error;
        SSDFB_CMD2(SSDFB_CMD_SET_COM_PINS_HARDWARE_CFG, sc->sc_p->p_compin_cfg);
        if (error)
                return error;
        if (sc->sc_upsidedown) {
                SSDFB_CMD1(SSDFB_CMD_SET_SEGMENT_REMAP_REVERSE);
                if (error)
                        return error;
                SSDFB_CMD1(SSDFB_CMD_SET_COM_OUTPUT_DIRECTION_REMAP);
                if (error)
                        return error;
        } else {
                SSDFB_CMD1(SSDFB_CMD_SET_SEGMENT_REMAP_NORMAL);
                if (error)
                        return error;
                SSDFB_CMD1(SSDFB_CMD_SET_COM_OUTPUT_DIRECTION_NORMAL);
                if (error)
                        return error;
        }
        SSDFB_CMD1(SSDFB_CMD_SET_NORMAL_DISPLAY + (uint8_t)sc->sc_inverse);
        if (error)
                return error;

        /*
         * Configure timing characteristics.
         */
        SSDFB_CMD2(SSDFB_CMD_SET_DISPLAY_CLOCK_RATIO,
            __SHIFTIN(sc->sc_p->p_fosc, SSDFB_DISPLAY_CLOCK_OSCILLATOR_MASK) |
            __SHIFTIN(sc->sc_p->p_fosc_div, SSDFB_DISPLAY_CLOCK_DIVIDER_MASK));
        if (error)
                return error;
        SSDFB_CMD2(SSDFB_CMD_SET_CONTRAST_CONTROL, sc->sc_contrast);
        if (error)
                return error;
        SSDFB_CMD2(SSDFB_CMD_SET_PRECHARGE_PERIOD,
            __SHIFTIN(sc->sc_p->p_precharge, SSDFB_PRECHARGE_MASK) |
            __SHIFTIN(sc->sc_p->p_discharge, SSDFB_DISCHARGE_MASK));
        if (error)
                return error;
        SSDFB_CMD2(SSDFB_CMD_SET_VCOMH_DESELECT_LEVEL,
            sc->sc_p->p_vcomh_deselect_level);
        if (error)
                return error;

        /*
         * Start charge pumps.
         */
        if (sc->sc_p->p_controller_id == SSDFB_CONTROLLER_SH1106) {
                SSDFB_CMD1(SH1106_CMD_SET_CHARGE_PUMP_7V4);
                if (error)
                        return error;
                SSDFB_CMD2(SH1106_CMD_SET_DC_DC, SH1106_DC_DC_ON);
                if (error)
                        return error;
        } else {
                SSDFB_CMD2(SSD1306_CMD_SET_CHARGE_PUMP,
                    SSD1306_CHARGE_PUMP_ENABLE);
                if (error)
                        return error;
        }

        ssdfb_clear_screen(sc);
        error = sc->sc_p->p_sync(sc, usepoll);
        if (error)
                return error;
        error = ssdfb_set_display_on(sc, true, usepoll);

        return error;
}

static int
ssdfb_init_ssd1322(struct ssdfb_softc *sc)
{
        int error;
        uint8_t cmd[3];
        bool usepoll = true;
        uint8_t remap;
        uint8_t dualcom;

        /*
         * Enter sleep.
         */
        SSDFB_CMD2(SSD1322_CMD_SET_COMMAND_LOCK, SSD1322_COMMAND_UNLOCK_MAGIC);
        if (error)
                return error;
        SSDFB_CMD1(SSD1322_CMD_SET_SLEEP_MODE_ON);
        if (error)
                return error;

        /*
         * Start charge pumps.
         */
        SSDFB_CMD2(SSD1322_CMD_FUNCTION_SELECTION,
            SSD1322_FUNCTION_SELECTION_INTERNAL_VDD);
        if (error)
                return error;
        SSDFB_CMD2(SSD1322_CMD_SET_VCOMH, sc->sc_p->p_vcomh_deselect_level);
        if (error)
                return error;
        SSDFB_CMD2(SSD1322_CMD_SET_PRE_CHARGE_VOLTAGE_LEVEL,
            SSD1322_DEFAULT_PRE_CHARGE_VOLTAGE_LEVEL);
        if (error)
                return error;
        SSDFB_CMD2(SSD1322_CMD_SET_GPIO,
            SSD1322_GPIO0_DISABLED | SSD1322_GPIO1_DISABLED);
        if (error)
                return error;

        /*
         * Configure timing characteristics.
         */
        SSDFB_CMD2(SSD1322_CMD_SET_FRONT_CLOCK_DIVIDER,
           __SHIFTIN(sc->sc_p->p_fosc, SSD1322_FREQUENCY_MASK) |
           __SHIFTIN(sc->sc_p->p_fosc_div, SSD1322_DIVIDER_MASK));
        if (error)
                return error;
        SSDFB_CMD2(SSD1322_CMD_SET_PHASE_LENGTH,
           __SHIFTIN(SSD1322_DEFAULT_PHASE_2,
            SSD1322_PHASE_LENGTH_PHASE_2_MASK) |
            __SHIFTIN(SSD1322_DEFAULT_PHASE_1,
            SSD1322_PHASE_LENGTH_PHASE_1_MASK));
        if (error)
                return error;
        SSDFB_CMD2(SSD1322_CMD_SET_SECOND_PRECHARGE_PERIOD,
            SSD1322_DEFAULT_SECOND_PRECHARGE_PERIOD);
        if (error)
                return error;

        /*
         * Configure physical display panel layout.
         */
        SSDFB_CMD2(SSD1322_CMD_SET_MULTIPLEX_RATIO, sc->sc_p->p_multiplex_ratio);
        if (error)
                return error;
        if (sc->sc_upsidedown)
                remap = 0x10;
        else
                remap = 0x2;
        dualcom = 0x1;
        if (sc->sc_p->p_multiplex_ratio <= 63)
                dualcom |= 0x10;
        SSDFB_CMD3(SSD1322_CMD_SET_REMAP_AND_DUAL_COM_LINE_MODE, remap, dualcom);
        if (error)
                return error;

        /*
         * Contrast settings.
         */
        SSDFB_CMD1(SSD1322_CMD_SET_DEFAULT_GRAY_SCALE_TABLE);
        if (error)
                return error;
        SSDFB_CMD3(SSD1322_CMD_DISPLAY_ENHANCEMENT_A,
            SSD1322_DISPLAY_ENHANCEMENT_A_MAGIC1,
            SSD1322_DISPLAY_ENHANCEMENT_A_MAGIC2);
        if (error)
                return error;
        SSDFB_CMD3(SSD1322_CMD_DISPLAY_ENHANCEMENT_B,
            SSD1322_DISPLAY_ENHANCEMENT_B_MAGIC1,
            SSD1322_DISPLAY_ENHANCEMENT_B_MAGIC2);
        if (error)
                return error;
        SSDFB_CMD2(SSD1322_CMD_SET_CONTRAST_CURRENT,
            sc->sc_contrast);
        if (error)
                return error;
        SSDFB_CMD2(SSD1322_CMD_MASTER_CONTRAST_CURRENT_CONTROL,
            SSD1322_DEFAULT_MASTER_CONTRAST_CURRENT_CONTROL);
        if (error)
                return error;

        /*
         * Reset display engine state.
         */
        SSDFB_CMD2(SSD1322_CMD_SET_DISPLAY_OFFSET, 0x00);
        if (error)
                return error;
        SSDFB_CMD2(SSD1322_CMD_SET_DISPLAY_START_LINE, 0x00);
        if (error)
                return error;
        SSDFB_CMD1(SSD1322_CMD_NORMAL_DISPLAY + (uint8_t)sc->sc_inverse);
        if (error)
                return error;
        SSDFB_CMD1(SSD1322_CMD_EXIT_PARTIAL_DISPLAY);
        if (error)
                return error;

        ssdfb_clear_screen(sc);
        error = ssdfb_sync(sc, usepoll);
        if (error)
                return error;

        error = ssdfb_set_display_on(sc, true, usepoll);

        return error;
}

static int
ssdfb_init_ssd1353(struct ssdfb_softc *sc)
{
        int error;
        uint8_t cmd[3];
        bool usepoll = true;
        uint8_t remap;

        /*
         * Enter sleep.
         */
        SSDFB_CMD2(SSD1353_CMD_SET_COMMAND_LOCK, SSD1353_COMMAND_UNLOCK_MAGIC);
        if (error)
                return error;
        SSDFB_CMD1(SSD1353_CMD_RESET);
        if (error)
                return error;
        SSDFB_CMD1(SSD1353_CMD_DEACTIVATE_SCROLL);
        if (error)
                return error;
        SSDFB_CMD1(SSD1353_CMD_SET_DISPLAY_OFF);
        if (error)
                return error;

        /*
         * Start charge pumps.
         */
        SSDFB_CMD2(SSD1353_CMD_SET_VCOMH, sc->sc_p->p_vcomh_deselect_level);
        if (error)
                return error;
        SSDFB_CMD2(SSD1353_CMD_SET_PRE_CHARGE_VOLTAGE_LEVEL,
            SSD1353_DEFAULT_PRE_CHARGE_VOLTAGE_LEVEL);
        if (error)
                return error;

        /*
         * Configure timing characteristics.
         */
        SSDFB_CMD2(SSD1353_CMD_SET_FRONT_CLOCK_DIVIDER,
           __SHIFTIN(sc->sc_p->p_fosc, SSD1322_FREQUENCY_MASK) |
           __SHIFTIN(sc->sc_p->p_fosc_div, SSD1322_DIVIDER_MASK));
        if (error)
                return error;
        SSDFB_CMD2(SSD1353_CMD_SET_PHASE_LENGTH,
           __SHIFTIN(SSD1353_DEFAULT_PHASE_2,
            SSD1322_PHASE_LENGTH_PHASE_2_MASK) |
            __SHIFTIN(SSD1353_DEFAULT_PHASE_1,
            SSD1322_PHASE_LENGTH_PHASE_1_MASK));
        if (error)
                return error;
        SSDFB_CMD2(SSD1353_CMD_SET_SECOND_PRECHARGE_PERIOD,
            SSD1353_DEFAULT_SECOND_PRECHARGE_PERIOD);
        if (error)
                return error;
        SSDFB_CMD2(SSD1353_CMD_SET_SECOND_PRECHARGE_SPEED,
            SSD1353_DEFAULT_SECOND_PRECHARGE_SPEED);
        if (error)
                return error;

        /*
         * Configure physical display panel layout.
         */
        SSDFB_CMD2(SSD1353_CMD_SET_MULTIPLEX_RATIO, sc->sc_p->p_multiplex_ratio);
        if (error)
                return error;
        remap = sc->sc_p->p_compin_cfg;
        if (sc->sc_upsidedown)
                remap ^= SSD1353_REMAP_COM_DIRECTION;
        else
                remap ^= SSD1353_REMAP_SEG_DIRECTION;
        SSDFB_CMD2(SSD1353_CMD_REMAP_COLOR_DEPTH, remap);
        if (error)
                return error;

        /*
         * Contrast settings.
         */
        SSDFB_CMD1(SSD1353_CMD_SET_DEFAULT_GRAY_SCALE_TABLE);
        if (error)
                return error;
        SSDFB_CMD2(SSD1353_CMD_SET_CONTRAST_CONTROL_A, sc->sc_contrast);
        if (error)
                return error;
        SSDFB_CMD2(SSD1353_CMD_SET_CONTRAST_CONTROL_B, sc->sc_contrast);
        if (error)
                return error;
        SSDFB_CMD2(SSD1353_CMD_SET_CONTRAST_CONTROL_C, sc->sc_contrast);
        if (error)
                return error;
        SSDFB_CMD2(SSD1353_CMD_MASTER_CURRENT_CONTROL,
            SSD1353_DEFAULT_MASTER_CURRENT_ATTENUATION);
        if (error)
                return error;

        /*
         * Reset display engine state.
         */
        SSDFB_CMD2(SSD1353_CMD_SET_DISPLAY_OFFSET, 0x00);
        if (error)
                return error;
        SSDFB_CMD2(SSD1353_CMD_SET_DISPLAY_START_LINE, 0x00);
        if (error)
                return error;
        SSDFB_CMD1(sc->sc_inverse
            ? SSD1353_CMD_INVERSE_DISPLAY
            : SSD1353_CMD_NORMAL_DISPLAY);
        if (error)
                return error;

        ssdfb_clear_screen(sc);
        error = ssdfb_sync(sc, usepoll);
        if (error)
                return error;

        error = ssdfb_set_display_on(sc, true, usepoll);

        return error;
}

static int
ssdfb_set_contrast(struct ssdfb_softc *sc, uint8_t value, bool usepoll)
{
        uint8_t cmd[2];
        int error;

        cmd[1] = sc->sc_contrast = value;
        switch (sc->sc_p->p_controller_id) {
        case SSDFB_CONTROLLER_SSD1322:
                cmd[0] = SSD1322_CMD_SET_CONTRAST_CURRENT;
                break;
        case SSDFB_CONTROLLER_SSD1353:
                cmd[0] = SSD1353_CMD_SET_CONTRAST_CONTROL_A;
                error = sc->sc_cmd(sc->sc_cookie, cmd, sizeof(cmd), usepoll);
                if (error)
                        return error;
                cmd[0] = SSD1353_CMD_SET_CONTRAST_CONTROL_B;
                error = sc->sc_cmd(sc->sc_cookie, cmd, sizeof(cmd), usepoll);
                if (error)
                        return error;
                cmd[0] = SSD1353_CMD_SET_CONTRAST_CONTROL_C;
                break;
        default:
                cmd[0] = SSDFB_CMD_SET_CONTRAST_CONTROL;
                break;
        }

        return sc->sc_cmd(sc->sc_cookie, cmd, sizeof(cmd), usepoll);
}

static int
ssdfb_set_display_on(struct ssdfb_softc *sc, bool value, bool usepoll)
{
        uint8_t cmd[1];
        int error;
        sc->sc_display_on = value;

        SSDFB_CMD1(value ? SSDFB_CMD_SET_DISPLAY_ON : SSDFB_CMD_SET_DISPLAY_OFF);

        return error;
}

static int
ssdfb_set_mode(struct ssdfb_softc *sc, u_int mode)
{
        switch (mode) {
        case WSDISPLAYIO_MODE_EMUL:
        case WSDISPLAYIO_MODE_DUMBFB:
                break;
        default:
                return EINVAL;
        }
        if (mode == sc->sc_mode)
                return 0;
        mutex_enter(&sc->sc_cond_mtx);
        sc->sc_mode = mode;
        cv_broadcast(&sc->sc_cond);
        mutex_exit(&sc->sc_cond_mtx);
        ssdfb_clear_screen(sc);
        ssdfb_damage(sc);

        return 0;
}

static void
ssdfb_damage(struct ssdfb_softc *sc)
{
        int s;

        if (sc->sc_usepoll) {
                (void) ssdfb_sync(sc, true);
        } else {
                /*
                 * kernel code isn't permitted to call us via kprintf at
                 * splhigh. In case misbehaving code calls us anyway we can't
                 * safely take the mutex so we skip the damage notification.
                 */
                if (sc->sc_is_console) {
                        s = splhigh();
                        splx(s);
                        if (s == IPL_HIGH)
                                return;
                }
                mutex_enter(&sc->sc_cond_mtx);
                sc->sc_modified = true;
                cv_broadcast(&sc->sc_cond);
                mutex_exit(&sc->sc_cond_mtx);
        }
}

static void
ssdfb_udv_attach(struct ssdfb_softc *sc)
{
        extern const struct cdevsw wsdisplay_cdevsw;
        dev_t dev;
#define WSDISPLAYMINOR(unit, screen)    (((unit) << 8) | (screen))
        dev = makedev(cdevsw_lookup_major(&wsdisplay_cdevsw),
            WSDISPLAYMINOR(device_unit(sc->sc_wsdisplay), 0));
        sc->sc_uobj = udv_attach(dev, VM_PROT_READ|VM_PROT_WRITE, 0,
            sc->sc_ri_bits_len);
}

static bool
ssdfb_is_modified(struct ssdfb_softc *sc)
{
        vaddr_t va, va_end;

        if (sc->sc_mode == WSDISPLAYIO_MODE_EMUL)
                return sc->sc_modified;

        if (sc->sc_uobj == NULL)
                return false;

        va = (vaddr_t)sc->sc_ri.ri_bits;
        va_end = va + sc->sc_ri_bits_len;
        while (va < va_end) {
                if (pmap_is_modified(uvm_pageratop(va)))
                        return true;
                va += PAGE_SIZE;
        }

        return false;
}

static bool
ssdfb_clear_modify(struct ssdfb_softc *sc)
{
        vaddr_t va, va_end;
        bool ret;

        if (sc->sc_mode == WSDISPLAYIO_MODE_EMUL) {
                mutex_enter(&sc->sc_cond_mtx);
                ret = sc->sc_modified;
                sc->sc_modified = false;
                mutex_exit(&sc->sc_cond_mtx);
                return ret;
        }

        if (sc->sc_uobj == NULL)
                return false;

        va = (vaddr_t)sc->sc_ri.ri_bits;
        va_end = va + sc->sc_ri_bits_len;
        ret = false;
        while (va < va_end) {
                if (pmap_clear_modify(uvm_pageratop(va)))
                        ret = true;
                va += PAGE_SIZE;
        }

        return ret;
}

static void
ssdfb_thread(void *arg)
{
        struct ssdfb_softc *sc = (struct ssdfb_softc *)arg;
        int error;

        mutex_enter(&sc->sc_cond_mtx);

        if (sc->sc_usepoll)
                ssdfb_set_usepoll(sc, false);

        while(!sc->sc_detaching) {
                if (sc->sc_mode == WSDISPLAYIO_MODE_DUMBFB &&
                    sc->sc_uobj == NULL) {
                        mutex_exit(&sc->sc_cond_mtx);
                        ssdfb_udv_attach(sc);
                        mutex_enter(&sc->sc_cond_mtx);
                }
                if (!ssdfb_is_modified(sc)) {
                        if (cv_timedwait(&sc->sc_cond, &sc->sc_cond_mtx,
                            sc->sc_mode == WSDISPLAYIO_MODE_EMUL
                            ? 0 : sc->sc_backoff) == EWOULDBLOCK
                            && sc->sc_backoff < mstohz(200)) {
                                sc->sc_backoff <<= 1;
                        }
                        continue;
                }
                sc->sc_backoff = 1;
                mutex_exit(&sc->sc_cond_mtx);
                (void) ssdfb_clear_modify(sc);
                if (!sc->sc_usepoll) {
                        error = ssdfb_sync(sc, false);
                        if (error)
                                device_printf(sc->sc_dev,
                                    "ssdfb_sync: error %d\n",
                                    error);
                }
                mutex_enter(&sc->sc_cond_mtx);
        }

        mutex_exit(&sc->sc_cond_mtx);
        kthread_exit(0);
}

static void
ssdfb_set_usepoll(struct ssdfb_softc *sc, bool enable)
{
        sc->sc_usepoll = enable;
}

static int
ssdfb_sync(struct ssdfb_softc *sc, bool usepoll)
{
        return sc->sc_p->p_sync(sc, usepoll);
}

static int
ssdfb_sync_ssd1306(struct ssdfb_softc *sc, bool usepoll)
{
        struct rasops_info *ri = &sc->sc_ri;
        int block_size = 8;
        int ri_block_stride = ri->ri_stride * block_size;
        int height_in_blocks = sc->sc_p->p_height / block_size;
        int width_in_blocks  = sc->sc_p->p_width / block_size;
        int ri_block_step = block_size * ri->ri_depth / 8;
        int x, y;
        union ssdfb_block *blockp;
        uint64_t raw_block;
        uint8_t *src;
        int x1, x2, y1, y2;

        /*
         * Transfer rasops bitmap into gddram shadow buffer while keeping track
         * of the bounding box of the dirty region we scribbled over.
         */
        x1 = width_in_blocks;
        x2 = -1;
        y1 = height_in_blocks;
        y2 = -1;
        for (y = 0; y < height_in_blocks; y++) {
                src = &ri->ri_bits[y * ri_block_stride];
                blockp = &sc->sc_gddram[y * width_in_blocks];
                for (x = 0; x < width_in_blocks; x++) {
                        raw_block = ssdfb_transpose_block(src, ri->ri_stride);
                        if (raw_block != blockp->raw) {
                                blockp->raw = raw_block;
                                if (x1 > x)
                                        x1 = x;
                                if (x2 < x)
                                        x2 = x;
                                if (y1 > y)
                                        y1 = y;
                                if (y2 < y)
                                        y2 = y;
                        }
                        src += ri_block_step;
                        blockp++;
                }
        }
        if (x2 != -1)
                return sc->sc_transfer_rect(sc->sc_cookie,
                    x1 * block_size + sc->sc_p->p_panel_shift,
                    (x2 + 1) * block_size - 1 + sc->sc_p->p_panel_shift,
                    y1,
                    y2,
                    &sc->sc_gddram[y1 * width_in_blocks + x1].col[0],
                    sc->sc_p->p_width,
                    usepoll);

        return 0;
}

static int
ssdfb_sync_ssd1322(struct ssdfb_softc *sc, bool usepoll)
{
        struct rasops_info *ri = &sc->sc_ri;
        int block_size_w = 4;
        int width = sc->sc_p->p_width;
        int height = sc->sc_p->p_height;
        int width_in_blocks = width / block_size_w;
        int x, y;
        uint16_t *blockp;
        uint16_t raw_block;
        uint16_t *src;
        uint32_t *src32;
        int x1, x2, y1, y2;

        /*
         * Transfer rasops bitmap into gddram shadow buffer while keeping track
         * of the bounding box of the dirty region we scribbled over.
         */
        x1 = width;
        x2 = -1;
        y1 = height;
        y2 = -1;
        blockp = (uint16_t*)sc->sc_gddram;
        for (y = 0; y < height; y++) {
                src = (uint16_t*)&ri->ri_bits[y * ri->ri_stride];
                src32 = (uint32_t*)src;
                for (x = 0; x < width_in_blocks; x++) {
#ifdef SSDFB_USE_NATIVE_DEPTH
                        raw_block =
                            ((*src << 12) & 0xf000) |
                            ((*src << 4)  & 0x0f00) |
                            ((*src >> 4)  & 0x00f0) |
                            ((*src >> 12) & 0x000f);
                        src++;
#else
                        raw_block =
#  if _BYTE_ORDER == _LITTLE_ENDIAN
                            ((*src32 <<  8) & 0x0f00) |
                            ((*src32 <<  4) & 0xf000) |
                            ((*src32 >> 16) & 0x000f) |
                            ((*src32 >> 20) & 0x00f0);
#  else
                            ((*src32 >> 24) & 0x000f) |
                            ((*src32 >> 12) & 0x00f0) |
                            ((*src32      ) & 0x0f00) |
                            ((*src32 << 12) & 0xf000);
#  endif
                        src32++;
#endif
                        if (raw_block != *blockp) {
                                *blockp = raw_block;
                                if (x1 > x)
                                        x1 = x;
                                if (x2 < x)
                                        x2 = x;
                                if (y1 > y)
                                        y1 = y;
                                if (y2 < y)
                                        y2 = y;
                        }
                        blockp++;
                }
        }
        blockp = (uint16_t*)sc->sc_gddram;
        if (x2 != -1)
                return sc->sc_transfer_rect(sc->sc_cookie,
                    x1 + sc->sc_p->p_panel_shift,
                    x2 + sc->sc_p->p_panel_shift,
                    y1,
                    y2,
                    (uint8_t*)&blockp[y1 * width_in_blocks + x1],
                    width * sc->sc_p->p_bits_per_pixel / 8,
                    usepoll);
        return 0;
}

static int
ssdfb_sync_ssd1353(struct ssdfb_softc *sc, bool usepoll)
{
        int width = sc->sc_p->p_width;
        int height = sc->sc_p->p_height;
        struct rasops_info *ri = &sc->sc_ri;
        int x, y;
        uint32_t *src, *blockp;
        int x1, x2, y1, y2;

        /*
         * Transfer rasops bitmap into gddram shadow buffer while keeping track
         * of the bounding box of the dirty region we scribbled over.
         */
        x1 = width;
        x2 = -1;
        y1 = height;
        y2 = -1;
        blockp = (uint32_t*)sc->sc_gddram;
        for (y = 0; y < height; y++) {
                src = (uint32_t*)&ri->ri_bits[y * ri->ri_stride];
                for (x = 0; x < width; x++) {
                        if (*blockp != *src) {
                                *blockp = *src;
                                if (x1 > x)
                                        x1 = x;
                                if (x2 < x)
                                        x2 = x;
                                if (y1 > y)
                                        y1 = y;
                                if (y2 < y)
                                        y2 = y;
                        }
                        blockp++;
                        src++;
                }
        }

        blockp = (uint32_t*)sc->sc_gddram;
        if (x2 != -1)
                return sc->sc_transfer_rect(sc->sc_cookie,
                    x1 + sc->sc_p->p_panel_shift,
                    x2 + sc->sc_p->p_panel_shift,
                    y1,
                    y2,
                    (uint8_t*)&blockp[y1 * width + x1],
                    width * sc->sc_p->p_bits_per_pixel / 8,
                    usepoll);
        return 0;
}

static uint64_t
ssdfb_transpose_block(uint8_t *src, size_t src_stride)
{
        uint64_t x = 0;
#ifdef SSDFB_USE_NATIVE_DEPTH
        uint64_t t;
        int i;

        /*
         * collect the 8x8 block.
         */
        for (i = 0; i < 8; i++) {
                x >>= 8;
                x |= (uint64_t)src[i * src_stride] << 56;
        }

        /*
         * Transpose it into gddram layout.
         * Post-transpose bswap is the same as pre-transpose bit order reversal.
         * We do this to match rasops1 bit order.
         */
        t = (x ^ (x >> 28)) & 0x00000000F0F0F0F0ULL;
        x = x ^ t ^ (t << 28);
        t = (x ^ (x >> 14)) & 0x0000CCCC0000CCCCULL;
        x = x ^ t ^ (t << 14);
        t = (x ^ (x >>  7)) & 0x00AA00AA00AA00AAULL;
        x = x ^ t ^ (t <<  7);
        x = bswap64(x);
#else
        int m, n;

        for (m = 0; m < 8; m++) {
                for (n = 0; n < 8; n++) {
                        x >>= 1;
                        x |= src[n * src_stride + m] ? (1ULL << 63) : 0;
                }
        }
#endif
        return htole64(x);
}

static const struct ssdfb_product *
ssdfb_lookup_product(ssdfb_product_id_t id)
{
        int i;

        for (i = 0; i < __arraycount(ssdfb_products); i++) {
                if (ssdfb_products[i].p_product_id == id)
                        return &ssdfb_products[i];
        }

        return NULL;
}

static int
ssdfb_pick_font(int *cookiep, struct wsdisplay_font **fontp)
{
        int error;
        int c;
        struct wsdisplay_font *f;
        int i;
        uint8_t d[4][2] = {{5, 8}, {8, 8}, {8, 10} ,{8, 16}};

        /*
         * Try to find fonts in order of increasing size.
         */
        wsfont_init();
        for(i = 0; i < __arraycount(d); i++) {
                c = wsfont_find(NULL, d[i][0], d[i][1], 0,
                    WSDISPLAY_FONTORDER_L2R, WSDISPLAY_FONTORDER_L2R,
                    WSFONT_FIND_BITMAP);
                if (c > 0)
                        break;
        }
        if (c <= 0)
                return ENOENT;
        error = wsfont_lock(c, &f);
        if (error)
                return error;
        *cookiep = c;
        *fontp = f;

        return 0;
}

static void
ssdfb_clear_screen(struct ssdfb_softc *sc)
{
        struct rasops_info *ri = &sc->sc_ri;

        memset(sc->sc_gddram, 0xff, sc->sc_gddram_len);
        memset(ri->ri_bits, 0, sc->sc_ri_bits_len);
}

#if defined(DDB)
static void
ssdfb_ddb_trap_callback(int enable)
{
        extern struct cfdriver ssdfb_cd;
        struct ssdfb_softc *sc;
        int i;

        for (i = 0; i < ssdfb_cd.cd_ndevs; i++) {
                sc = device_lookup_private(&ssdfb_cd, i);
                if (sc != NULL && sc->sc_is_console) {
                        ssdfb_set_usepoll(sc, (bool)enable);
                }
        }
}
#endif