Re: [PATCH v5 05/20] nubus: move slot bitmap checks from NubusDevice realize() to BusClass check_address()

[Philippe Mathieu-Daudé]

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

Allow Nubus to manage the slot allocations itself using the BusClass 
check_address()
virtual function rather than managing this during NubusDevice realize().

Signed-off-by: Mark Cave-Ayland <mark.cave-ayl...@ilande.co.uk>
Reviewed-by: Laurent Vivier <laur...@vivier.eu>
---
  hw/nubus/nubus-bus.c    | 30 ++++++++++++++++++++++++++++++
  hw/nubus/nubus-device.c | 22 ----------------------
  2 files changed, 30 insertions(+), 22 deletions(-)

diff --git a/hw/nubus/nubus-bus.c b/hw/nubus/nubus-bus.c
index 3cd7534864..d4daaa36f2 100644
--- a/hw/nubus/nubus-bus.c
+++ b/hw/nubus/nubus-bus.c
@@ -96,11 +96,41 @@ static void nubus_init(Object *obj)
                                                   NUBUS_SLOT_NB);
  }

+static bool nubus_check_address(BusState *bus, DeviceState *dev, Error **errp)

+{
+    NubusDevice *nd = NUBUS_DEVICE(dev);
+    NubusBus *nubus = NUBUS_BUS(bus);
+    uint16_t s;
+
+    if (nd->slot == -1) {
+        /* No slot specified, find first available free slot */
+        s = ctz32(nubus->slot_available_mask);

Same comment than previous patch:

           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 false;
+        }
+    } 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 false;
+        }
+    }
+
+    nubus->slot_available_mask &= ~BIT(nd->slot);
+    return true;
+}