m68k: Add NeXTcube framebuffer device emulation

The NeXTcube uses a linear framebuffer with 4 greyscale colors and
a fixed resolution of 1120 * 832.
This code has been taken from Bryce Lanham's GSoC 2011 NeXT branch at

 https://github.com/blanham/qemu-NeXT/blob/next-cube/hw/next-fb.c

and altered to fit the latest interface of the current QEMU (e.g.
the device has been "qdev"-ified etc.).

Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20190831074519.32613-2-huth@tuxfamily.org>
Signed-off-by: Thomas Huth <huth@tuxfamily.org>

default-configs/m68k-softmmu.mak

@@ -6,3 +6,4 @@ CONFIG_SEMIHOSTING=y
 #
 CONFIG_AN5206=y
 CONFIG_MCF5208=y
+CONFIG_NEXTCUBE=y

hw/display/Makefile.objs

@@ -38,6 +38,7 @@ common-obj-$(CONFIG_RASPI) += bcm2835_fb.o
 common-obj-$(CONFIG_SM501) += sm501.o
 common-obj-$(CONFIG_TCX) += tcx.o
 common-obj-$(CONFIG_CG3) += cg3.o
+common-obj-$(CONFIG_NEXTCUBE) += next-fb.o
 
 obj-$(CONFIG_VGA) += vga.o
 

hw/display/next-fb.c

@@ -0,0 +1,146 @@
+/*
+ * NeXT Cube/Station Framebuffer Emulation
+ *
+ * Copyright (c) 2011 Bryce Lanham
+ *
+ * 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 "qemu/osdep.h"
+#include "qapi/error.h"
+#include "ui/console.h"
+#include "hw/hw.h"
+#include "hw/boards.h"
+#include "hw/loader.h"
+#include "hw/display/framebuffer.h"
+#include "ui/pixel_ops.h"
+#include "hw/m68k/next-cube.h"
+
+#define NEXTFB(obj) OBJECT_CHECK(NeXTFbState, (obj), TYPE_NEXTFB)
+
+struct NeXTFbState {
+    SysBusDevice parent_obj;
+
+    MemoryRegion fb_mr;
+    MemoryRegionSection fbsection;
+    QemuConsole *con;
+
+    uint32_t cols;
+    uint32_t rows;
+    int invalidate;
+};
+typedef struct NeXTFbState NeXTFbState;
+
+static void nextfb_draw_line(void *opaque, uint8_t *d, const uint8_t *s,
+                             int width, int pitch)
+{
+    NeXTFbState *nfbstate = NEXTFB(opaque);
+    static const uint32_t pal[4] = {
+        0xFFFFFFFF, 0xFFAAAAAA, 0xFF555555, 0xFF000000
+    };
+    uint32_t *buf = (uint32_t *)d;
+    int i = 0;
+
+    for (i = 0; i < nfbstate->cols / 4; i++) {
+        int j = i * 4;
+        uint8_t src = s[i];
+        buf[j + 3] = pal[src & 0x3];
+        src >>= 2;
+        buf[j + 2] = pal[src & 0x3];
+        src >>= 2;
+        buf[j + 1] = pal[src & 0x3];
+        src >>= 2;
+        buf[j + 0] = pal[src & 0x3];
+    }
+}
+
+static void nextfb_update(void *opaque)
+{
+    NeXTFbState *s = NEXTFB(opaque);
+    int dest_width = 4;
+    int src_width;
+    int first = 0;
+    int last  = 0;
+    DisplaySurface *surface = qemu_console_surface(s->con);
+
+    src_width = s->cols / 4 + 8;
+    dest_width = s->cols * 4;
+
+    if (s->invalidate) {
+        framebuffer_update_memory_section(&s->fbsection, &s->fb_mr, 0,
+                                          s->cols, src_width);
+        s->invalidate = 0;
+    }
+
+    framebuffer_update_display(surface, &s->fbsection, s->cols, s->rows,
+                               src_width, dest_width, 0, 1, nextfb_draw_line,
+                               s, &first, &last);
+
+    dpy_gfx_update(s->con, 0, 0, s->cols, s->rows);
+}
+
+static void nextfb_invalidate(void *opaque)
+{
+    NeXTFbState *s = NEXTFB(opaque);
+    s->invalidate = 1;
+}
+
+static const GraphicHwOps nextfb_ops = {
+    .invalidate  = nextfb_invalidate,
+    .gfx_update  = nextfb_update,
+};
+
+static void nextfb_realize(DeviceState *dev, Error **errp)
+{
+    NeXTFbState *s = NEXTFB(dev);
+
+    memory_region_init_ram(&s->fb_mr, OBJECT(dev), "next-video", 0x1CB100,
+                           &error_fatal);
+    sysbus_init_mmio(SYS_BUS_DEVICE(dev), &s->fb_mr);
+
+    s->invalidate = 1;
+    s->cols = 1120;
+    s->rows = 832;
+
+    s->con = graphic_console_init(dev, 0, &nextfb_ops, s);
+    qemu_console_resize(s->con, s->cols, s->rows);
+}
+
+static void nextfb_class_init(ObjectClass *oc, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(oc);
+
+    set_bit(DEVICE_CATEGORY_DISPLAY, dc->categories);
+    dc->realize = nextfb_realize;
+
+    /* Note: This device does not any state that we have to reset or migrate */
+}
+
+static const TypeInfo nextfb_info = {
+    .name          = TYPE_NEXTFB,
+    .parent        = TYPE_SYS_BUS_DEVICE,
+    .instance_size = sizeof(NeXTFbState),
+    .class_init    = nextfb_class_init,
+};
+
+static void nextfb_register_types(void)
+{
+    type_register_static(&nextfb_info);
+}
+
+type_init(nextfb_register_types)

hw/m68k/Kconfig

@@ -7,3 +7,7 @@ config MCF5208
     bool
     select COLDFIRE
     select PTIMER
+
+config NEXTCUBE
+    bool
+    select FRAMEBUFFER

include/hw/m68k/next-cube.h

@@ -0,0 +1,7 @@
+
+#ifndef NEXT_CUBE_H
+#define NEXT_CUBE_H
+
+#define TYPE_NEXTFB "next-fb"
+
+#endif /* NEXT_CUBE_H */