From f98dc1f79469dca98c6ff666ce6a5ba0fe280ad7 Mon Sep 17 00:00:00 2001
From: RichardG867 <richardg867@gmail.com>
Date: Sat, 18 Apr 2020 14:43:46 -0300
Subject: [PATCH] Sync floppy drive types to CMOS on coreboot machines

---
 src/floppy/fdd.c        |  7 ++++++
 src/include/86box/fdd.h |  1 +
 src/nvr_at.c            | 49 ++++++++++++++++++++++++++++++++++++++++-
 3 files changed, 56 insertions(+), 1 deletion(-)

diff --git a/src/floppy/fdd.c b/src/floppy/fdd.c
index 791c82abd..a2a5342af 100644
--- a/src/floppy/fdd.c
+++ b/src/floppy/fdd.c
@@ -407,6 +407,13 @@ fdd_is_dd(int drive)
 }
 
 
+int
+fdd_is_hd(int drive)
+{
+    return drive_types[fdd[drive].type].flags & FLAG_HOLE1;
+}
+
+
 int
 fdd_is_ed(int drive)
 {
diff --git a/src/include/86box/fdd.h b/src/include/86box/fdd.h
index b486b617d..ccd420924 100644
--- a/src/include/86box/fdd.h
+++ b/src/include/86box/fdd.h
@@ -43,6 +43,7 @@ extern int	fdd_can_read_medium(int drive);
 extern int	fdd_doublestep_40(int drive);
 extern int	fdd_is_525(int drive);
 extern int	fdd_is_dd(int drive);
+extern int	fdd_is_hd(int drive);
 extern int	fdd_is_ed(int drive);
 extern int	fdd_is_double_sided(int drive);
 extern void	fdd_set_head(int drive, int head);
diff --git a/src/nvr_at.c b/src/nvr_at.c
index d95a6d7c0..403fc62f7 100644
--- a/src/nvr_at.c
+++ b/src/nvr_at.c
@@ -237,6 +237,7 @@
 #include <86box/rom.h>
 #include <86box/device.h>
 #include <86box/nvr.h>
+#include <86box/fdd.h>
 
 
 /* RTC registers and bit definitions. */
@@ -279,6 +280,8 @@
 # define REGC_UF	0x10
 #define RTC_REGD	13
 # define REGD_VRT	0x80
+#define RTC_FDD_TYPES	0x10
+#define RTC_INST_EQUIP	0x14
 #define RTC_CENTURY_AT	0x32		/* century register for AT etc */
 #define RTC_CENTURY_PS	0x37		/* century register for PS/1 PS/2 */
 #define RTC_ALDAY	0x7D		/* VIA VT82C586B - alarm day */
@@ -753,7 +756,7 @@ nvr_reset(nvr_t *nvr)
 static void
 nvr_start(nvr_t *nvr)
 {
-    int i;
+    int i, fdd;
     local_t *local = (local_t *) nvr->data;
 
     struct tm tm;
@@ -768,6 +771,50 @@ nvr_start(nvr_t *nvr)
 	nvr->regs[0x0e] = 0xff;		/* If load failed or it loaded an uninitialized NVR,
 					   mark everything as bad. */
 
+    if (machines[machine].flags & MACHINE_COREBOOT) {
+    	/* Sync floppy drive types on coreboot machines, as SeaBIOS lacks a setup
+    	   utility and just leaves these untouched. */
+
+    	nvr->regs[RTC_FDD_TYPES] = 0x00;
+    	nvr->regs[RTC_INST_EQUIP] |= 0xc0;
+
+    	for (i = 0; i <= 1; i++) {
+    		fdd = fdd_get_type(i);
+    		if (fdd) {
+    			if (fdd_is_525(i)) {
+    				if (fdd_is_hd(i))
+    					fdd = 2;
+    				else if (fdd_doublestep_40(i))
+    					fdd = 3;
+    				else
+    					fdd = 1;
+    			} else {
+    				if (fdd_is_hd(i))
+    					fdd = 4;
+    				else if (fdd_is_double_sided(i))
+    					fdd = 3;
+    				else
+    					fdd = 1;
+    			}
+
+    			nvr->regs[RTC_FDD_TYPES] |= (fdd << ((1 - i) * 4));
+    			nvr->regs[RTC_INST_EQUIP] &= 0x3f; /* At least one drive installed. */
+    		}
+    	}
+
+    	if ((nvr->regs[RTC_FDD_TYPES] >> 4) && (nvr->regs[RTC_FDD_TYPES] & 0xf))
+    		nvr->regs[RTC_INST_EQUIP] |= 0x40; /* Two drives installed. */
+
+    	/* Re-compute CMOS checksum. SeaBIOS also doesn't care about the checksum,
+    	   but Windows does. */
+    	uint16_t checksum = 0;
+    	for (i = 0x10; i <= 0x2d; i++) {
+	    	checksum += nvr->regs[i];
+    	}
+    	nvr->regs[0x2e] = checksum >> 8;
+    	nvr->regs[0x2f] = checksum;
+    }
+
     /* Initialize the internal and chip times. */
     if (time_sync & TIME_SYNC_ENABLED) {
 	/* Use the internal clock's time. */