fdc: add function to determine drive chs limits

When populating ACPI objects for floppy drives one needs to provide the
maximum values for cylinder, sector, and head number the drive supports.

This patch adds a function that iterates through the array of predefined
floppy drive formats and returns the maximum values of c, h, s, out of
those matching the given floppy drive type.
Signed-off-by: NRoman Kagan <rkagan@virtuozzo.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Marcel Apfelbaum <marcel@redhat.com>
Cc: John Snow <jsnow@redhat.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Kevin O'Connor <kevin@koconnor.net>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Reviewed-by: NJohn Snow <jsnow@redhat.com>

hw/block/fdc.c

@@ -2557,6 +2557,29 @@ FloppyDriveType isa_fdc_get_drive_type(ISADevice *fdc, int i)
     return isa->state.drives[i].drive;
 }
 
+void isa_fdc_get_drive_max_chs(FloppyDriveType type,
+                               uint8_t *maxc, uint8_t *maxh, uint8_t *maxs)
+{
+    const FDFormat *fdf;
+
+    *maxc = *maxh = *maxs = 0;
+    for (fdf = fd_formats; fdf->drive != FLOPPY_DRIVE_TYPE_NONE; fdf++) {
+        if (fdf->drive != type) {
+            continue;
+        }
+        if (*maxc < fdf->max_track) {
+            *maxc = fdf->max_track;
+        }
+        if (*maxh < fdf->max_head) {
+            *maxh = fdf->max_head;
+        }
+        if (*maxs < fdf->last_sect) {
+            *maxs = fdf->last_sect;
+        }
+    }
+    (*maxc)--;
+}
+
 static const VMStateDescription vmstate_isa_fdc ={
     .name = "fdc",
     .version_id = 2,

include/hw/block/fdc.h

@@ -15,5 +15,7 @@ void sun4m_fdctrl_init(qemu_irq irq, hwaddr io_base,
                        DriveInfo **fds, qemu_irq *fdc_tc);
 
 FloppyDriveType isa_fdc_get_drive_type(ISADevice *fdc, int i);
+void isa_fdc_get_drive_max_chs(FloppyDriveType type,
+                               uint8_t *maxc, uint8_t *maxh, uint8_t *maxs);
 
 #endif