board/vfd.c: Add stub emu for "VFD" LCD

board/meson.build

@@ -30,5 +30,7 @@ board_lib = static_library(
         'slider-cmd.h',
         'slider-frame.c',
         'slider-frame.h',
+        'vfd.c',
+        'vfd.h',
     ],
 )

board/vfd.c

@@ -0,0 +1,62 @@
+/* This is some sort of LCD display found on various cabinets. It is driven
+   directly by amdaemon, and it has something to do with displaying the status
+   of electronic payments.
+
+   Part number in schematics is "VFD GP1232A02A FUTABA".
+
+   Little else about this board is known. Black-holing the RS232 comms that it
+   receives seems to be sufficient for the time being. */
+
+#include <windows.h>
+
+#include <assert.h>
+#include <stdint.h>
+
+#include "board/vfd.h"
+
+#include "hook/iohook.h"
+
+#include "hooklib/uart.h"
+
+#include "util/dprintf.h"
+#include "util/dump.h"
+
+static HRESULT vfd_handle_irp(struct irp *irp);
+
+static struct uart vfd_uart;
+static uint8_t vfd_written[512];
+static uint8_t vfd_readable[512];
+
+HRESULT vfd_hook_init(unsigned int port_no)
+{
+    uart_init(&vfd_uart, port_no);
+    vfd_uart.written.bytes = vfd_written;
+    vfd_uart.written.nbytes = sizeof(vfd_written);
+    vfd_uart.readable.bytes = vfd_readable;
+    vfd_uart.readable.nbytes = sizeof(vfd_readable);
+
+    return iohook_push_handler(vfd_handle_irp);
+}
+
+static HRESULT vfd_handle_irp(struct irp *irp)
+{
+    HRESULT hr;
+
+    assert(irp != NULL);
+
+    if (!uart_match_irp(&vfd_uart, irp)) {
+        return iohook_invoke_next(irp);
+    }
+
+    hr = uart_handle_irp(&vfd_uart, irp);
+
+    if (FAILED(hr) || irp->op != IRP_OP_WRITE) {
+        return hr;
+    }
+
+    dprintf("VFD TX:\n");
+    dump(vfd_uart.written.bytes, vfd_uart.written.pos);
+    vfd_uart.written.pos = 0;
+
+    return hr;
+}

board/vfd.h

@@ -0,0 +1,5 @@
+#pragma once
+
+#include <windows.h>
+
+HRESULT vfd_hook_init(unsigned int port_no);