system/dev/display/astro-display/canvas.c

// Copyright 2018 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "astro-display.h"

void config_canvas(astro_display_t* display) {
    uint32_t fbh = display->disp_info.height * 2;
    uint32_t fbw = display->disp_info.stride * 2;

    DISP_INFO("Canvas Diminsions: w=%d h=%d\n", fbw, fbh);

    // set framebuffer address in DMC, read/modify/write
    WRITE32_DMC_REG(DMC_CAV_LUT_DATAL,
        (((io_buffer_phys(&display->fbuffer) + 7) >> 3) & DMC_CAV_ADDR_LMASK) |
             ((((fbw + 7) >> 3) & DMC_CAV_WIDTH_LMASK) << DMC_CAV_WIDTH_LBIT));

    WRITE32_DMC_REG(DMC_CAV_LUT_DATAH,
        ((((fbw + 7) >> 3) >> DMC_CAV_WIDTH_LWID) << DMC_CAV_WIDTH_HBIT) |
             ((fbh & DMC_CAV_HEIGHT_MASK) << DMC_CAV_HEIGHT_BIT));

    WRITE32_DMC_REG(DMC_CAV_LUT_ADDR, DMC_CAV_LUT_ADDR_WR_EN | OSD2_DMC_CAV_INDEX );
    // read a cbus to make sure last write finish.
    READ32_DMC_REG(DMC_CAV_LUT_DATAH);

}