From fc345a46a726c545acfbdc5f625fb0d08a76094f Mon Sep 17 00:00:00 2001
From: Tau <tau@nowhere>
Date: Sun, 3 Nov 2019 15:37:29 -0500
Subject: [PATCH] board/sg-reader.c: Improve life cycle

---
 board/sg-reader.c | 35 +++++++++++++++++++++++++++--------
 1 file changed, 27 insertions(+), 8 deletions(-)

diff --git a/board/sg-reader.c b/board/sg-reader.c
index 8274e26..518e5ea 100644
--- a/board/sg-reader.c
+++ b/board/sg-reader.c
@@ -39,6 +39,8 @@ static const struct sg_led_ops sg_reader_led_ops = {
 };
 
 static CRITICAL_SECTION sg_reader_lock;
+static bool sg_reader_started;
+static HRESULT sg_reader_start_hr;
 static struct uart sg_reader_uart;
 static uint8_t sg_reader_written_bytes[520];
 static uint8_t sg_reader_readable_bytes[520];
@@ -49,20 +51,12 @@ HRESULT sg_reader_hook_init(
         const struct aime_config *cfg,
         unsigned int port_no)
 {
-    HRESULT hr;
-
     assert(cfg != NULL);
 
     if (!cfg->enable) {
         return S_FALSE;
     }
 
-    hr = aime_io_init();
-
-    if (FAILED(hr)) {
-        return hr;
-    }
-
     sg_nfc_init(&sg_reader_nfc, 0x00, &sg_reader_nfc_ops, NULL);
     sg_led_init(&sg_reader_led, 0x08, &sg_reader_led_ops, NULL);
 
@@ -112,6 +106,31 @@ static HRESULT sg_reader_handle_irp_locked(struct irp *irp)
     }
 #endif
 
+    if (irp->op == IRP_OP_OPEN) {
+        /* Unfortunately the card reader UART gets opened and closed
+           repeatedly */
+
+        if (!sg_reader_started) {
+            dprintf("NFC Assembly: Starting backend DLL\n");
+            hr = aime_io_init();
+
+            sg_reader_started = true;
+            sg_reader_start_hr = hr;
+
+            if (FAILED(hr)) {
+                dprintf("NFC Assembly: Backend error: %x\n", (int) hr);
+
+                return hr;
+            }
+        } else {
+            hr = sg_reader_start_hr;
+
+            if (FAILED(hr)) {
+                return hr;
+            }
+        }
+    }
+
     hr = uart_handle_irp(&sg_reader_uart, irp);
 
     if (FAILED(hr) || irp->op != IRP_OP_WRITE) {