Re: [PATCH v5 04/20] nubus: use bitmap to manage available slots

[Philippe Mathieu-Daudé]

On 9/23/21 11:12, Mark Cave-Ayland wrote:

Convert nubus_device_realize() to use a bitmap to manage available slots to 
allow
for future Nubus devices to be plugged into arbitrary slots from the command 
line
using a new qdev "slot" parameter for nubus devices.

Update mac_nubus_bridge_init() to only allow slots 0x9 to 0xe on a Macintosh
machines as documented in "Desigining Cards and Drivers for the Macintosh 
Family".

Signed-off-by: Mark Cave-Ayland <mark.cave-ayl...@ilande.co.uk>
---
  hw/nubus/mac-nubus-bridge.c         |  4 ++++
  hw/nubus/nubus-bus.c                |  5 +++--
  hw/nubus/nubus-device.c             | 32 +++++++++++++++++++++++------
  include/hw/nubus/mac-nubus-bridge.h |  4 ++++
  include/hw/nubus/nubus.h            | 13 ++++++------
  5 files changed, 43 insertions(+), 15 deletions(-)

diff --git a/hw/nubus/nubus-device.c b/hw/nubus/nubus-device.c
index 4e23df1280..562650a05b 100644
--- a/hw/nubus/nubus-device.c
+++ b/hw/nubus/nubus-device.c
@@ -160,14 +160,28 @@ static void nubus_device_realize(DeviceState *dev, Error 
**errp)
      NubusDevice *nd = NUBUS_DEVICE(dev);
      char *name;
      hwaddr slot_offset;
-
-    if (nubus->current_slot < NUBUS_FIRST_SLOT ||
-            nubus->current_slot > NUBUS_LAST_SLOT) {
-        error_setg(errp, "Cannot register nubus card, not enough slots");
-        return;
+    uint16_t s;
+
+    if (nd->slot == -1) {
+        /* No slot specified, find first available free slot */
+        s = ctz32(nubus->slot_available_mask);

Nitpicking:

           int s = ctz32(nubus->slot_available_mask);

Otherwise,
Reviewed-by: Philippe Mathieu-Daudé <f4...@amsat.org>

+        if (s != 32) {
+            nd->slot = s;
+        } else {
+            error_setg(errp, "Cannot register nubus card, no free slot "
+                             "available");
+            return;
+        }
+    } else {
+        /* Slot specified, make sure the slot is available */
+        if (!(nubus->slot_available_mask & BIT(nd->slot))) {
+            error_setg(errp, "Cannot register nubus card, slot %d is "
+                             "unavailable or already occupied", nd->slot);
+            return;
+        }
      }