From 41f26b57c2409a9827300a7d064f218309d46582 Mon Sep 17 00:00:00 2001
From: Cacodemon345 <wahil1976@outlook.com>
Date: Sat, 6 May 2023 23:19:55 +0600
Subject: [PATCH] usb: Start work on SOF generation and frame counting

---
 src/include/86box/usb.h |  8 +++++++-
 src/usb.c               | 44 ++++++++++++++++++++++++-----------------
 2 files changed, 33 insertions(+), 19 deletions(-)

diff --git a/src/include/86box/usb.h b/src/include/86box/usb.h
index 39ddf9cf6..af1922570 100644
--- a/src/include/86box/usb.h
+++ b/src/include/86box/usb.h
@@ -36,7 +36,13 @@ typedef struct
 /* USB Host Controller device struct */
 typedef struct usb_t
 {
-    uint8_t       uhci_io[32], ohci_mmio[4096];
+    union
+    {
+        uint8_t  ohci_mmio[4096];
+        uint16_t ohci_mmio_w[2048];
+        uint32_t ohci_mmio_l[1024];
+    };
+    uint8_t       uhci_io[32];
     uint16_t      uhci_io_base;
     int           uhci_enable, ohci_enable;
     uint32_t      ohci_mem_base;
diff --git a/src/usb.c b/src/usb.c
index 0951412d6..3310c0786 100644
--- a/src/usb.c
+++ b/src/usb.c
@@ -63,7 +63,7 @@ enum
     OHCI_HcBulkHeadED = 0x28,
     OHCI_HcBulkCurrentED = 0x2C,
     OHCI_HcDoneHead = 0x30,
-    OHCI_HcFMInterval = 0x34,
+    OHCI_HcFmInterval = 0x34,
     OHCI_HcFmRemaining = 0x38,
     OHCI_HcFmNumber = 0x3C,
     OHCI_HcPeriodicStart = 0x40,
@@ -223,10 +223,35 @@ ohci_mmio_read(uint32_t addr, void *p)
     return ret;
 }
 
+void
+ohci_set_interrupt(usb_t* usb, uint8_t bit)
+{
+    if (!(usb->ohci_mmio[OHCI_HcInterruptEnable + 3] & 0x80))
+        return;
+    
+    if (!(usb->ohci_mmio[OHCI_HcInterruptEnable] & bit))
+        return;
+
+    if (usb->ohci_mmio[OHCI_HcInterruptDisable] & bit)
+        return;
+
+    usb->ohci_mmio[OHCI_HcInterruptStatus] |= bit;
+    usb_interrupt_ohci(usb);
+}
+
 void
 ohci_update_frame_counter(void* priv)
 {
     usb_t *dev = (usb_t *) priv;
+
+    dev->ohci_mmio_w[OHCI_HcFmRemaining / 2] &= 0x3fff;
+    if (dev->ohci_mmio_w[OHCI_HcFmRemaining / 2] == 0) {
+        dev->ohci_mmio_w[OHCI_HcFmRemaining / 2] = dev->ohci_mmio_w[OHCI_HcFmInterval / 2] & 0x3fff;
+        dev->ohci_mmio_l[OHCI_HcFmRemaining / 4] &= ~(1 << 31);
+        dev->ohci_mmio_l[OHCI_HcFmRemaining / 4] |= dev->ohci_mmio_l[OHCI_HcFmInterval / 4] & (1 << 31);
+        ohci_set_interrupt(dev, OHCI_HcInterruptEnable_SO);
+    }
+    if (dev->ohci_mmio_w[OHCI_HcFmRemaining / 2]) dev->ohci_mmio_w[OHCI_HcFmRemaining / 2]--;
 }
 
 void
@@ -257,23 +282,6 @@ ohci_port_reset_callback_2(void* priv)
     dev->ohci_mmio[OHCI_HcRhPortStatus2] &= ~0x10;
     dev->ohci_mmio[OHCI_HcRhPortStatus2 + 2] |= 0x10;
 }
-
-void
-ohci_set_interrupt(usb_t* usb, uint8_t bit)
-{
-    if (!(usb->ohci_mmio[OHCI_HcInterruptEnable + 3] & 0x80))
-        return;
-    
-    if (!(usb->ohci_mmio[OHCI_HcInterruptEnable] & bit))
-        return;
-
-    if (usb->ohci_mmio[OHCI_HcInterruptDisable] & bit)
-        return;
-
-    usb->ohci_mmio[OHCI_HcInterruptStatus] |= bit;
-    usb_interrupt_ohci(usb);
-}
-
 static void
 ohci_mmio_write(uint32_t addr, uint8_t val, void *p)
 {