qemu: add bochs-display support

Use coreboot text mode emulation to also support the qemu bochs-display
device.  This is a new display device supporting simple linear
framebuffers, using the bochs register interface.  No support for legacy
vga (text modes, planar modes, cga modes, 8bpp palette modes all
dropped).  The bochs interface is compatible with the qemu stdvga.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

1 files changed, 59 insertions, 0 deletions

diff --git a/vgasrc/bochsdisplay.c b/vgasrc/bochsdisplay.c
new file mode 100644
index 00000000..e1f90f96
--- /dev/null
+++ b/vgasrc/bochsdisplay.c
@@ -0,0 +1,59 @@
+#include "biosvar.h" // GET_BDA
+#include "output.h" // dprintf
+#include "string.h" // memset16_far
+#include "bochsvga.h" // VBE_BOCHS_*
+#include "hw/pci.h" // pci_config_readl
+#include "hw/pci_regs.h" // PCI_BASE_ADDRESS_0
+#include "vgautil.h" // VBE_total_memory
+
+#define FRAMEBUFFER_WIDTH      1024
+#define FRAMEBUFFER_HEIGHT     768
+#define FRAMEBUFFER_BPP        4
+#define FRAMEBUFFER_STRIDE     (FRAMEBUFFER_BPP * FRAMEBUFFER_WIDTH)
+#define FRAMEBUFFER_SIZE       (FRAMEBUFFER_STRIDE * FRAMEBUFFER_HEIGHT)
+
+int
+bochs_display_setup(void)
+{
+    dprintf(1, "bochs-display: setup called\n");
+
+    if (GET_GLOBAL(HaveRunInit))
+        return 0;
+
+    int bdf = GET_GLOBAL(VgaBDF);
+    if (bdf == 0)
+        return 0;
+
+    u32 bar = pci_config_readl(bdf, PCI_BASE_ADDRESS_0);
+    u32 lfb_addr = bar & PCI_BASE_ADDRESS_MEM_MASK;
+    bar = pci_config_readl(bdf, PCI_BASE_ADDRESS_2);
+    u32 io_addr = bar & PCI_BASE_ADDRESS_IO_MASK;
+    dprintf(1, "bochs-display: bdf %02x:%02x.%x, bar 0 at 0x%x, bar 1 at 0x%x\n"
+            , pci_bdf_to_bus(bdf) , pci_bdf_to_dev(bdf), pci_bdf_to_fn(bdf),
+            lfb_addr, io_addr);
+
+    u16 *dispi = (void*)(io_addr + 0x500);
+    u8 *vga = (void*)(io_addr + 0x400);
+    u16 id = readw(dispi + VBE_DISPI_INDEX_ID);
+    dprintf(1, "bochs-display: id is 0x%x, %s\n", id
+            , id == VBE_DISPI_ID5 ? "good" : "FAIL");
+    if (id != VBE_DISPI_ID5)
+        return 0;
+
+     dprintf(1, "bochs-display: using %dx%d, %d bpp (%d stride)\n"
+            , FRAMEBUFFER_WIDTH, FRAMEBUFFER_HEIGHT
+            , FRAMEBUFFER_BPP * 8, FRAMEBUFFER_STRIDE);
+
+    cbvga_setup_modes(lfb_addr, FRAMEBUFFER_BPP * 8,
+                      FRAMEBUFFER_WIDTH, FRAMEBUFFER_HEIGHT,
+                      FRAMEBUFFER_STRIDE);
+
+    writew(dispi + VBE_DISPI_INDEX_XRES,   FRAMEBUFFER_WIDTH);
+    writew(dispi + VBE_DISPI_INDEX_YRES,   FRAMEBUFFER_HEIGHT);
+    writew(dispi + VBE_DISPI_INDEX_BPP,    FRAMEBUFFER_BPP * 8);
+    writew(dispi + VBE_DISPI_INDEX_ENABLE, VBE_DISPI_ENABLED);
+
+    writeb(vga, 0x20); /* unblank (for qemu -device VGA) */
+
+    return 0;
+}