From d791464dd01c09c300dca927bd0e629c85a401ba Mon Sep 17 00:00:00 2001
From: Tau <tau@nowhere>
Date: Thu, 8 Nov 2018 10:15:34 -0500
Subject: [PATCH] nu/gpio.c: Add emulated GPIO controller

---
 nu/gpio.c      | 184 +++++++++++++++++++++++++++++++++++++++++++++++++
 nu/gpio.h      |  12 ++++
 nu/guid.c      |   1 +
 nu/meson.build |   2 +
 4 files changed, 199 insertions(+)
 create mode 100644 nu/gpio.c
 create mode 100644 nu/gpio.h

diff --git a/nu/gpio.c b/nu/gpio.c
new file mode 100644
index 00000000..2060937b
--- /dev/null
+++ b/nu/gpio.c
@@ -0,0 +1,184 @@
+#include <windows.h>
+#include <ntstatus.h>
+
+#include <assert.h>
+#include <string.h>
+
+#include "hook/iohook.h"
+
+#include "nu/gpio.h"
+
+#include "util/dprintf.h"
+#include "util/setupapi.h"
+
+enum {
+    GPIO_IOCTL_SET_LEDS     = 0x8000A004,
+    GPIO_IOCTL_GET_PSW      = 0x80006008,
+    GPIO_IOCTL_GET_DIPSW    = 0x8000600C,
+    GPIO_IOCTL_DESCRIBE     = 0x80006014,
+};
+
+enum {
+    GPIO_TYPE_NONE  = 0,
+    GPIO_TYPE_LED   = 1,
+    GPIO_TYPE_DIPSW = 2,
+    GPIO_TYPE_PSW   = 3,
+};
+
+#pragma pack(push, 1)
+
+struct gpio_port {
+    uint8_t unknown;
+
+    /* Number of distinct instances of this thing..? */
+    uint8_t count;
+
+    /* Type of GPIO port */
+    uint16_t type;
+};
+
+struct gpio_ports {
+    uint8_t unknown; /* Maybe a count of valid items in the array idk */
+    struct gpio_port ports[32];
+};
+
+#pragma pack(pop)
+
+static HRESULT gpio_handle_irp(struct irp *irp);
+static HRESULT gpio_handle_open(struct irp *irp);
+static HRESULT gpio_handle_close(struct irp *irp);
+static HRESULT gpio_handle_ioctl(struct irp *irp);
+
+static HRESULT gpio_ioctl_get_psw(struct irp *irp);
+static HRESULT gpio_ioctl_get_dipsw(struct irp *irp);
+static HRESULT gpio_ioctl_describe(struct irp *irp);
+static HRESULT gpio_ioctl_set_leds(struct irp *irp);
+
+static HANDLE gpio_fd;
+
+static const struct gpio_ports gpio_ports = {
+    .ports = {
+        {
+            .type       = GPIO_TYPE_LED,
+            .count      = 2,
+        }, {
+            .type       = GPIO_TYPE_DIPSW,
+            .count      = 8,
+        }, {
+            .type       = GPIO_TYPE_PSW,
+            .count      = 2,
+        }
+    },
+};
+
+_Static_assert(sizeof(gpio_ports) == 129, "GPIO port map size");
+
+void gpio_hook_init(void)
+{
+    gpio_fd = iohook_open_dummy_fd();
+    iohook_push_handler(gpio_handle_irp);
+    setupapi_add_phantom_dev(&gpio_guid, L"$gpio");
+}
+
+static HRESULT gpio_handle_irp(struct irp *irp)
+{
+    assert(irp != NULL);
+
+    if (irp->op != IRP_OP_OPEN && irp->fd != gpio_fd) {
+        return iohook_invoke_next(irp);
+    }
+
+    switch (irp->op) {
+    case IRP_OP_OPEN:   return gpio_handle_open(irp);
+    case IRP_OP_CLOSE:  return gpio_handle_close(irp);
+    case IRP_OP_IOCTL:  return gpio_handle_ioctl(irp);
+    default:            return HRESULT_FROM_WIN32(ERROR_INVALID_FUNCTION);
+    }
+}
+
+static HRESULT gpio_handle_open(struct irp *irp)
+{
+    if (wcscmp(irp->open_filename, L"$gpio") != 0) {
+        return iohook_invoke_next(irp);
+    }
+
+    dprintf("GPIO: Open device\n");
+    irp->fd = gpio_fd;
+
+    return S_OK;
+}
+
+static HRESULT gpio_handle_close(struct irp *irp)
+{
+    dprintf("GPIO: Close device\n");
+
+    return S_OK;
+}
+
+static HRESULT gpio_handle_ioctl(struct irp *irp)
+{
+    switch (irp->ioctl) {
+    case GPIO_IOCTL_SET_LEDS:
+        return gpio_ioctl_set_leds(irp);
+
+    case GPIO_IOCTL_GET_PSW:
+        return gpio_ioctl_get_psw(irp);
+
+    case GPIO_IOCTL_GET_DIPSW:
+        return gpio_ioctl_get_dipsw(irp);
+
+    case GPIO_IOCTL_DESCRIBE:
+        return gpio_ioctl_describe(irp);
+
+    default:
+        dprintf("GPIO: IOCTL %08x write %i read %i\n",
+                irp->ioctl,
+                irp->write.nbytes,
+                irp->read.nbytes);
+
+        return HRESULT_FROM_WIN32(ERROR_INVALID_FUNCTION);
+    }
+}
+
+static HRESULT gpio_ioctl_get_dipsw(struct irp *irp)
+{
+    uint32_t dipsw;
+
+    dipsw = 0xff;
+    //dprintf("GPIO: Get dipsw %08x\n", dipsw);
+
+    return iobuf_write_le32(&irp->read, dipsw);
+}
+
+static HRESULT gpio_ioctl_get_psw(struct irp *irp)
+{
+    uint32_t result;
+
+    result = 0;
+
+    /* Bit 0 == SW1 == Alt. Test */
+    /* Bit 1 == SW2 == Alt. Service */
+
+    return iobuf_write_le32(&irp->read, result);
+}
+
+static HRESULT gpio_ioctl_describe(struct irp *irp)
+{
+    dprintf("GPIO: Describe GPIO ports\n");
+
+    if (irp->read.nbytes < sizeof(gpio_ports)) {
+        dprintf("GPIO: Descriptor read buffer too small\n");
+
+        return HRESULT_FROM_WIN32(ERROR_INSUFFICIENT_BUFFER);
+    }
+
+    memcpy(irp->read.bytes, &gpio_ports, sizeof(gpio_ports));
+    irp->read.pos = sizeof(gpio_ports);
+
+    return S_OK;
+}
+
+static HRESULT gpio_ioctl_set_leds(struct irp *irp)
+{
+    return S_OK;
+}
diff --git a/nu/gpio.h b/nu/gpio.h
new file mode 100644
index 00000000..e09da753
--- /dev/null
+++ b/nu/gpio.h
@@ -0,0 +1,12 @@
+#pragma once
+
+#include <windows.h>
+
+DEFINE_GUID(
+        gpio_guid,
+        0xE9A26688,
+        0xF522,
+        0x44FA,
+        0xBF, 0xEE, 0x59, 0xDD, 0x16, 0x15, 0x56, 0x6C);
+
+void gpio_hook_init(void);
diff --git a/nu/guid.c b/nu/guid.c
index 75a8ab64..c01c1b63 100644
--- a/nu/guid.c
+++ b/nu/guid.c
@@ -3,4 +3,5 @@
 
 #include "nu/ds.h"
 #include "nu/eeprom.h"
+#include "nu/gpio.h"
 #include "nu/sram.h"
diff --git a/nu/meson.build b/nu/meson.build
index 301db403..a7b3a712 100644
--- a/nu/meson.build
+++ b/nu/meson.build
@@ -12,6 +12,8 @@ nu_lib = static_library(
         'ds.h',
         'eeprom.c',
         'eeprom.h',
+        'gpio.c',
+        'gpio.h',
         'guid.c',
         'nvram.c',
         'nvram.h',