[Qemu-devel] [PATCH v8 3/4] fdc: add function to determine drive chs limits

[Roman Kagan <rkagan@virtuozzo.com>]

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: Roman 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>
---
changes since v7:
 - use drive max c,h,s rather than the current diskette geometry

 hw/block/fdc.c         | 23 +++++++++++++++++++++++
 include/hw/block/fdc.h |  2 ++
 2 files changed, 25 insertions(+)

diff --git a/hw/block/fdc.c b/hw/block/fdc.c
index 9838d21..fc3aef9 100644
--- a/hw/block/fdc.c
+++ b/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,
diff --git a/include/hw/block/fdc.h b/include/hw/block/fdc.h
index adce14f..1749dab 100644
--- a/include/hw/block/fdc.h
+++ b/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
-- 
2.5.0