floppy: Use timer_check() in floppy_wait_irq()

Use timer_check() instead of using floppy_motor_counter in BDA for the
timeout check in floppy_wait_irq().

The problem with using floppy_motor_counter was that, after it reaches
0, it immediately stops the floppy motors, which is not what is
supposed to happen on real hardware. Instead, after a timeout (like in
the end of every floppy operation, regardless of the result - success,
timeout or error), the floppy motors must be kept spinning for
additional 2 seconds (the FLOPPY_MOTOR_TICKS). So, now the
floppy_motor_counter is initialized to 255 (the max value) in the
beginning of the floppy operation. For IRQ timeouts, a different
timeout is used, specified by the new FLOPPY_IRQ_TIMEOUT constant
(currently set to 5 seconds - a fairly conservative value, but should
work reliably on most floppies).

After the floppy operation, floppy_drive_pio() resets the
floppy_motor_counter to 2 seconds (FLOPPY_MOTOR_TICKS).

This is also consistent with what other PC BIOSes do.

Signed-off-by: Nikolay Nikolov <nickysn@users.sourceforge.net>

diff --git a/src/hw/floppy.c b/src/hw/floppy.c
index 77dbade3153dfc0933300423256f210539bb6cb4..3012b3aab072b4a99dcce32f918e5efd73300432 100644 (file)
--- a/src/hw/floppy.c
+++ b/src/hw/floppy.c
@@ -34,6 +34,7 @@
 #define FLOPPY_GAPLEN 0x1B
 #define FLOPPY_FORMAT_GAPLEN 0x6c
 #define FLOPPY_PIO_TIMEOUT 1000
+#define FLOPPY_IRQ_TIMEOUT 5000
 
 #define FLOPPY_DOR_MOTOR_D     0x80 // Set to turn drive 3's motor ON
 #define FLOPPY_DOR_MOTOR_C     0x40 // Set to turn drive 2's motor ON
@@ -221,8 +222,9 @@ floppy_wait_irq(void)
 {
     u8 frs = GET_BDA(floppy_recalibration_status);
     SET_BDA(floppy_recalibration_status, frs & ~FRS_IRQ);
+    u32 end = timer_calc(FLOPPY_IRQ_TIMEOUT);
     for (;;) {
-        if (!GET_BDA(floppy_motor_counter)) {
+        if (timer_check(end)) {
             warn_timeout();
             floppy_disable_controller();
             return DISK_RET_ETIMEOUT;
@@ -324,7 +326,6 @@ static int
 floppy_enable_controller(void)
 {
     dprintf(2, "Floppy_enable_controller\n");
-    SET_BDA(floppy_motor_counter, FLOPPY_MOTOR_TICKS);
     // Clear the reset bit (enter reset state), but set 'enable IRQ and DMA'
     floppy_dor_mask(FLOPPY_DOR_RESET, FLOPPY_DOR_IRQ);
     // Set the reset bit (normal operation) and keep 'enable IRQ and DMA' on
@@ -348,8 +349,8 @@ floppy_drive_pio(u8 floppyid, int command, u8 *param)
             return ret;
     }
 
-    // reset the disk motor timeout value of INT 08
-    SET_BDA(floppy_motor_counter, FLOPPY_MOTOR_TICKS);
+    // set the disk motor timeout value of INT 08 to the highest value
+    SET_BDA(floppy_motor_counter, 255);
 
     // Turn on motor of selected drive, DMA & int enabled, normal operation
     floppy_dor_write((floppyid ? FLOPPY_DOR_MOTOR_B : FLOPPY_DOR_MOTOR_A) | FLOPPY_DOR_IRQ | FLOPPY_DOR_RESET | floppyid);