idac: add ffb emulation

board/config.c

@@ -93,3 +93,11 @@ void vfd_config_load(struct vfd_config *cfg, const wchar_t *filename)
     cfg->port = GetPrivateProfileIntW(L"vfd", L"portNo", 0, filename);
     cfg->utf_conversion = GetPrivateProfileIntW(L"vfd", L"utfConversion", 0, filename);
 }
+
+void ffb_config_load(struct ffb_config *cfg, const wchar_t *filename)
+{
+    assert(cfg != NULL);
+    assert(filename != NULL);
+
+    cfg->enable = GetPrivateProfileIntW(L"ffb", L"enable", 1, filename);
+}

board/config.h

@@ -6,7 +6,9 @@
 #include "board/io4.h"
 #include "board/sg-reader.h"
 #include "board/vfd.h"
+#include "board/ffb.h"
 
 void aime_config_load(struct aime_config *cfg, const wchar_t *filename);
 void io4_config_load(struct io4_config *cfg, const wchar_t *filename);
 void vfd_config_load(struct vfd_config *cfg, const wchar_t *filename);
+void ffb_config_load(struct ffb_config *cfg, const wchar_t *filename);

board/ffb.c

@@ -0,0 +1,234 @@
+/*
+    Force Feedback Board (FFB)
+
+    This board is used by many SEGA games to provide force feedback to the player.
+    It is driven by the game software over a serial connection and is used by many
+    games such as SEGA World Drivers Championship, Initial D Arcade, ...
+
+    Part number in schematics is "838-15069 MOTOR DRIVE BD RS232/422 Board".
+
+    Some observations:
+    The maximal strength for any effect is 127, except Damper which maxes out at 40.
+    The period for rumble effects is in the range 0-40.
+*/
+
+#include "board/ffb.h"
+
+#include <assert.h>
+#include <stdint.h>
+#include <windows.h>
+
+#include "hook/iohook.h"
+#include "hooklib/uart.h"
+#include "util/dprintf.h"
+#include "util/dump.h"
+
+
+// request format:
+// 0x?? - sync + command
+// 0x?? - direction/additional command
+// 0x?? - strength
+// 0x?? - checksum (sum of everything except the sync byte)
+
+enum {
+    FFB_CMD_TOGGLE = 0x80,
+    FFB_CMD_CONSTANT_FORCE = 0x84,
+    FFB_CMD_RUMBLE = 0x85,
+    FFB_CMD_DAMPER = 0x86,
+};
+
+struct ffb_hdr {
+    uint8_t cmd;
+};
+
+union ffb_req_any {
+    struct ffb_hdr hdr;
+    uint8_t bytes[3];
+};
+
+static HRESULT ffb_handle_irp(struct irp *irp);
+
+static HRESULT ffb_req_dispatch(const union ffb_req_any *req);
+static HRESULT ffb_req_toggle(const uint8_t *bytes);
+static HRESULT ffb_req_constant_force(const uint8_t *bytes);
+static HRESULT ffb_req_rumble(const uint8_t *bytes);
+static HRESULT ffb_req_damper(const uint8_t *bytes);
+
+static const struct ffb_ops *ffb_ops;
+static struct uart ffb_uart;
+
+static bool ffb_started;
+static HRESULT ffb_start_hr;
+static uint8_t ffb_written[4];
+static uint8_t ffb_readable[4];
+
+/* Static variables to store maximum strength values */
+static uint8_t max_constant_force = 0;
+static uint8_t max_rumble = 0;
+static uint8_t max_period = 0;
+static uint8_t max_damper = 0;
+
+HRESULT ffb_hook_init(
+        const struct ffb_config *cfg,
+        const struct ffb_ops *ops,
+        unsigned int port_no)
+{
+    assert(cfg != NULL);
+    assert(ops != NULL);
+
+    if (!cfg->enable) {
+        return S_FALSE;
+    }
+
+    ffb_ops = ops;
+
+    uart_init(&ffb_uart, port_no);
+    ffb_uart.written.bytes = ffb_written;
+    ffb_uart.written.nbytes = sizeof(ffb_written);
+    ffb_uart.readable.bytes = ffb_readable;
+    ffb_uart.readable.nbytes = sizeof(ffb_readable);
+
+    dprintf("FFB: hook enabled.\n");
+
+    return iohook_push_handler(ffb_handle_irp);
+}
+
+static HRESULT ffb_handle_irp(struct irp *irp)
+{
+    HRESULT hr;
+
+    assert(irp != NULL);
+
+    if (!uart_match_irp(&ffb_uart, irp)) {
+        return iohook_invoke_next(irp);
+    }
+
+    hr = uart_handle_irp(&ffb_uart, irp);
+
+    if (FAILED(hr) || irp->op != IRP_OP_WRITE) {
+        return hr;
+    }
+
+    assert(&ffb_uart.written != NULL);
+    assert(ffb_uart.written.bytes != NULL || ffb_uart.written.nbytes == 0);
+    assert(ffb_uart.written.pos <= ffb_uart.written.nbytes);
+
+    // dprintf("FFB TX:\n");
+
+    hr = ffb_req_dispatch((const union ffb_req_any *) ffb_uart.written.bytes);
+
+    if (FAILED(hr)) {
+        dprintf("FFB: Processing error: %x\n", (int)hr);
+    }
+
+    // dump_iobuf(&ffb_uart.written);
+    ffb_uart.written.pos = 0;
+
+    return hr;
+}
+
+static HRESULT ffb_req_dispatch(const union ffb_req_any *req)
+{
+    switch (req->hdr.cmd) {
+    case FFB_CMD_TOGGLE:
+        return ffb_req_toggle(req->bytes);
+    case FFB_CMD_CONSTANT_FORCE:
+        return ffb_req_constant_force(req->bytes);
+    case FFB_CMD_RUMBLE:
+        return ffb_req_rumble(req->bytes);
+    case FFB_CMD_DAMPER:
+        return ffb_req_damper(req->bytes);
+    /* There are some test mode specfic commands which doesn't seem to be used in
+       game at all. The same is true for the initialization phase. */
+
+    default:
+        dprintf("FFB: Unhandled command %02x\n", req->hdr.cmd);
+
+        return S_OK;
+    }
+}
+
+static HRESULT ffb_req_toggle(const uint8_t *bytes)
+{
+    uint8_t activate = bytes[2];
+
+    if (activate == 0x01) {
+        dprintf("FFB: Activated\n");
+    } else {
+        dprintf("FFB: Deactivated\n");
+    }
+
+    if (ffb_ops->toggle != NULL) {
+        ffb_ops->toggle(activate == 0x01);
+    }
+
+    return S_OK;
+}
+
+static HRESULT ffb_req_constant_force(const uint8_t *bytes)
+{
+    // dprintf("FFB: Constant force\n");
+
+    uint8_t direction = bytes[1];
+    uint8_t force = bytes[2];
+
+    if (direction == 0x0) {
+        // Right
+        force = 128 - force;
+    }
+
+    // Update max strength if the current force is greater
+    if (force > max_constant_force) {
+        max_constant_force = force;
+    }
+
+    // dprintf("FFB: Constant Force Strength: %d (Max: %d)\n", force, max_constant_force);
+    if (ffb_ops->constant_force != NULL) {
+        ffb_ops->constant_force(direction, force);
+    }
+
+    return S_OK;
+}
+
+static HRESULT ffb_req_rumble(const uint8_t *bytes)
+{
+    // dprintf("FFB: Rumble\n");
+
+    uint8_t force = bytes[1];
+    uint8_t period = bytes[2];
+
+    // Update max strength if the current force is greater
+    if (force > max_rumble) {
+        max_rumble = force;
+    }
+
+    if (period > max_period) {
+        max_period = period;
+    }
+
+    // dprintf("FFB: Rumble Period: %d (Min %d, Max %d), Strength: %d (Max: %d)\n", period, min_period, max_period, force, max_rumble);
+    if (ffb_ops->rumble != NULL) {
+        ffb_ops->rumble(force, period);
+    }
+
+    return S_OK;
+}
+
+static HRESULT ffb_req_damper(const uint8_t *bytes)
+{
+    // dprintf("FFB: Damper\n");
+
+    uint8_t force = bytes[2];
+
+    // Update max strength if the current force is greater
+    if (force > max_damper) {
+        max_damper = force;
+    }
+
+    // dprintf("FFB: Damper Strength: %d (Max: %d)\n", force, max_damper);
+    if (ffb_ops->damper != NULL) {
+        ffb_ops->damper(force);
+    }
+
+    return S_OK;
+}

board/ffb.h

@@ -0,0 +1,20 @@
+#pragma once
+
+#include <windows.h>
+#include <stdbool.h>
+
+struct ffb_config {
+    bool enable;
+};
+
+struct ffb_ops {
+    void (*toggle)(bool active);
+    void (*constant_force)(uint8_t direction, uint8_t force);
+    void (*rumble)(uint8_t force, uint8_t period);
+    void (*damper)(uint8_t force);
+};
+
+HRESULT ffb_hook_init(
+        const struct ffb_config *cfg,
+        const struct ffb_ops *ops,
+        unsigned int port_no);

board/meson.build

@@ -50,5 +50,7 @@ board_lib = static_library(
         'vfd-cmd.h',
         'vfd-frame.c',
         'vfd-frame.h',
+        'ffb.c',
+        'ffb.h'
     ],
 )