circuitpython/shared-module/sharpdisplay/SharpMemoryFramebuffer.c

/*
 * This file is part of the MicroPython project, http://micropython.org/
 *
 * The MIT License (MIT)
 *
 * Copyright (c) 2020 Jeff Epler for Adafruit Industries
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

#include <string.h>

#include "py/gc.h"

#include "shared-bindings/board/__init__.h"
#include "shared-bindings/microcontroller/Pin.h"
#include "shared-bindings/sharpdisplay/SharpMemoryFramebuffer.h"
#include "shared-module/sharpdisplay/SharpMemoryFramebuffer.h"

#include "supervisor/memory.h"

#define SHARPMEM_BIT_WRITECMD_LSB (0x80)
#define SHARPMEM_BIT_VCOM_LSB (0x40)

STATIC uint8_t bitrev(uint8_t n) {
    uint8_t r = 0;
    for (int i = 0; i < 8; i++) {r |= ((n >> i) & 1) << (7 - i);
    }
    return r;
}

int common_hal_sharpdisplay_framebuffer_get_width(sharpdisplay_framebuffer_obj_t *self) {
    return self->width;
}

int common_hal_sharpdisplay_framebuffer_get_height(sharpdisplay_framebuffer_obj_t *self) {
    return self->height;
}

int common_hal_sharpdisplay_framebuffer_get_row_stride(sharpdisplay_framebuffer_obj_t *self) {
    return (self->width + 7) / 8 + 2;
}

int common_hal_sharpdisplay_framebuffer_get_first_pixel_offset(sharpdisplay_framebuffer_obj_t *self) {
    return 2;
}

bool common_hal_sharpdisplay_framebuffer_get_reverse_pixels_in_byte(sharpdisplay_framebuffer_obj_t *self) {
    return true;
}

bool common_hal_sharpdisplay_framebuffer_get_pixels_in_byte_share_row(sharpdisplay_framebuffer_obj_t *self) {
    return true;
}

void common_hal_sharpdisplay_framebuffer_reset(sharpdisplay_framebuffer_obj_t *self) {
    if (self->bus != &self->inline_bus
        #if BOARD_SPI
        && self->bus != common_hal_board_get_spi()
        #endif
        ) {
        memcpy(&self->inline_bus, self->bus, sizeof(busio_spi_obj_t));
        self->bus = &self->inline_bus;
    }
}

void common_hal_sharpdisplay_framebuffer_reconstruct(sharpdisplay_framebuffer_obj_t *self) {
    // Look up the allocation by the old pointer and get the new pointer from it.
    supervisor_allocation *alloc = allocation_from_ptr(self->bufinfo.buf);
    self->bufinfo.buf = alloc ? alloc->ptr : NULL;
}

void common_hal_sharpdisplay_framebuffer_get_bufinfo(sharpdisplay_framebuffer_obj_t *self, mp_buffer_info_t *bufinfo) {
    if (!self->bufinfo.buf) {
        int row_stride = common_hal_sharpdisplay_framebuffer_get_row_stride(self);
        int height = common_hal_sharpdisplay_framebuffer_get_height(self);
        self->bufinfo.len = row_stride * height + 2;
        supervisor_allocation *alloc = allocate_memory(align32_size(self->bufinfo.len), false, true);
        if (alloc == NULL) {
            m_malloc_fail(self->bufinfo.len);
        }
        self->bufinfo.buf = alloc->ptr;
        memset(alloc->ptr, 0, self->bufinfo.len);

        uint8_t *data = self->bufinfo.buf;
        *data++ = SHARPMEM_BIT_WRITECMD_LSB;

        for (int y = 0; y < height; y++) {
            *data = bitrev(y + 1);
            data += row_stride;
        }
        self->full_refresh = true;
    }
    if (bufinfo) {
        *bufinfo = self->bufinfo;
    }
}

void common_hal_sharpdisplay_framebuffer_deinit(sharpdisplay_framebuffer_obj_t *self) {
    if (self->base.type != &sharpdisplay_framebuffer_type) {
        return;
    }

    if (self->bus == &self->inline_bus) {
        common_hal_busio_spi_deinit(self->bus);
    }

    common_hal_reset_pin(self->chip_select.pin);

    free_memory(allocation_from_ptr(self->bufinfo.buf));

    memset(self, 0, sizeof(*self));
}

void common_hal_sharpdisplay_framebuffer_construct(sharpdisplay_framebuffer_obj_t *self, busio_spi_obj_t *spi, mcu_pin_obj_t *chip_select, int baudrate, int width, int height) {
    common_hal_digitalio_digitalinout_construct(&self->chip_select, chip_select);
    common_hal_digitalio_digitalinout_switch_to_output(&self->chip_select, true, DRIVE_MODE_PUSH_PULL);
    common_hal_never_reset_pin(chip_select);

    self->bus = spi;
    common_hal_busio_spi_never_reset(self->bus);

    self->width = width;
    self->height = height;
    self->baudrate = baudrate;

    common_hal_sharpdisplay_framebuffer_get_bufinfo(self, NULL);
}

void common_hal_sharpdisplay_framebuffer_swapbuffers(sharpdisplay_framebuffer_obj_t *self, uint8_t *dirty_row_bitmask) {
    // claim SPI bus
    if (!common_hal_busio_spi_try_lock(self->bus)) {
        return;
    }
    common_hal_busio_spi_configure(self->bus, self->baudrate, 0, 0, 8);

    // set chip select high
    common_hal_digitalio_digitalinout_set_value(&self->chip_select, true);

    // output the toggling signal
    uint8_t *data = self->bufinfo.buf;
    data[0] ^= SHARPMEM_BIT_VCOM_LSB;

    common_hal_busio_spi_write(self->bus, data++, 1);

    // output each changed row
    size_t row_stride = common_hal_sharpdisplay_framebuffer_get_row_stride(self);
    for (int y = 0; y < self->height; y++) {
        if (self->full_refresh || (dirty_row_bitmask[y / 8] & (1 << (y & 7)))) {
            common_hal_busio_spi_write(self->bus, data, row_stride);
        }
        data += row_stride;
    }

    // output a trailing zero
    common_hal_busio_spi_write(self->bus, data, 1);

    // set chip select low
    common_hal_digitalio_digitalinout_set_value(&self->chip_select, false);

    // release SPI bus
    common_hal_busio_spi_unlock(self->bus);

    self->full_refresh = false;
}

STATIC void sharpdisplay_framebuffer_deinit(mp_obj_t self_in) {
    sharpdisplay_framebuffer_obj_t *self = self_in;
    common_hal_sharpdisplay_framebuffer_deinit(self);
}

STATIC void sharpdisplay_framebuffer_get_bufinfo(mp_obj_t self_in, mp_buffer_info_t *bufinfo) {
    sharpdisplay_framebuffer_obj_t *self = self_in;
    common_hal_sharpdisplay_framebuffer_get_bufinfo(self, bufinfo);
}

STATIC int sharpdisplay_framebuffer_get_color_depth(mp_obj_t self_in) {
    return 1;
}

STATIC int sharpdisplay_framebuffer_get_height(mp_obj_t self_in) {
    sharpdisplay_framebuffer_obj_t *self = self_in;
    return common_hal_sharpdisplay_framebuffer_get_height(self);
}

STATIC int sharpdisplay_framebuffer_get_width(mp_obj_t self_in) {
    sharpdisplay_framebuffer_obj_t *self = self_in;
    return common_hal_sharpdisplay_framebuffer_get_width(self);
}

STATIC int sharpdisplay_framebuffer_get_first_pixel_offset(mp_obj_t self_in) {
    sharpdisplay_framebuffer_obj_t *self = self_in;
    return common_hal_sharpdisplay_framebuffer_get_first_pixel_offset(self);
}

STATIC bool sharpdisplay_framebuffer_get_pixels_in_byte_share_row(mp_obj_t self_in) {
    sharpdisplay_framebuffer_obj_t *self = self_in;
    return common_hal_sharpdisplay_framebuffer_get_pixels_in_byte_share_row(self);
}

STATIC bool sharpdisplay_framebuffer_get_reverse_pixels_in_byte(mp_obj_t self_in) {
    sharpdisplay_framebuffer_obj_t *self = self_in;
    return common_hal_sharpdisplay_framebuffer_get_reverse_pixels_in_byte(self);
}

STATIC int sharpdisplay_framebuffer_get_row_stride(mp_obj_t self_in) {
    sharpdisplay_framebuffer_obj_t *self = self_in;
    return common_hal_sharpdisplay_framebuffer_get_row_stride(self);
}

STATIC void sharpdisplay_framebuffer_swapbuffers(mp_obj_t self_in, uint8_t *dirty_row_bitmask) {
    sharpdisplay_framebuffer_obj_t *self = self_in;
    common_hal_sharpdisplay_framebuffer_swapbuffers(self, dirty_row_bitmask);
}

const framebuffer_p_t sharpdisplay_framebuffer_proto = {
    MP_PROTO_IMPLEMENT(MP_QSTR_protocol_framebuffer)
    .deinit = sharpdisplay_framebuffer_deinit,
    .get_bufinfo = sharpdisplay_framebuffer_get_bufinfo,
    .get_color_depth = sharpdisplay_framebuffer_get_color_depth,
    .get_height = sharpdisplay_framebuffer_get_height,
    .get_width = sharpdisplay_framebuffer_get_width,
    .swapbuffers = sharpdisplay_framebuffer_swapbuffers,

    .get_first_pixel_offset = sharpdisplay_framebuffer_get_first_pixel_offset,
    .get_pixels_in_byte_share_row = sharpdisplay_framebuffer_get_pixels_in_byte_share_row,
    .get_reverse_pixels_in_byte = sharpdisplay_framebuffer_get_reverse_pixels_in_byte,
    .get_row_stride = sharpdisplay_framebuffer_get_row_stride,
};

void common_hal_sharpdisplay_framebuffer_collect_ptrs(sharpdisplay_framebuffer_obj_t *self) {
    gc_collect_ptr(self->bus);
}