[Qemu-ppc] [PATCH 46/77] pci: Use the new pci_can_add_device() to enforce devfn_min/max

[Benjamin Herrenschmidt]

This adds a devfn_max field to PCIBus and adds a pci_can_add_device()
function which, if no "addr" (aka devfn) is specified, will tell whether
there is any slot free between devfn_min and devfn_max.

This will be used by some PCI root complex implementations that support
only one direct child to avoid having qemu put dumb devices at different
slot numbers.

Signed-off-by: Benjamin Herrenschmidt <address@hidden>
---
 hw/pci/pci.c             | 22 ++++++++++++++++++++++
 include/hw/pci/pci_bus.h |  1 +
 2 files changed, 23 insertions(+)

diff --git a/hw/pci/pci.c b/hw/pci/pci.c
index 168b9cc..7003f7c 100644
--- a/hw/pci/pci.c
+++ b/hw/pci/pci.c
@@ -108,6 +108,27 @@ static uint16_t pcibus_numa_node(PCIBus *bus)
     return NUMA_NODE_UNASSIGNED;
 }
 
+static bool pci_can_add_device(BusState *bus, QemuOpts *opts)
+{
+    unsigned int devfn, max;
+    PCIBus *pbus = PCI_BUS(bus);
+
+    /* If address is specified, say yes and let it fail if that doesn't work */
+    if (qemu_opt_get(opts, "addr") != NULL) {
+        return true;
+    }
+    max = ARRAY_SIZE(pbus->devices);
+    if (pbus->devfn_max && pbus->devfn_max < max) {
+       max = pbus->devfn_max;
+    }
+    for (devfn = pbus->devfn_min ; devfn < max; devfn += PCI_FUNC_MAX) {
+        if (!pbus->devices[devfn]) {
+            break;
+        }
+    }
+    return devfn < max;
+}
+
 static void pci_bus_class_init(ObjectClass *klass, void *data)
 {
     BusClass *k = BUS_CLASS(klass);
@@ -119,6 +140,7 @@ static void pci_bus_class_init(ObjectClass *klass, void 
*data)
     k->realize = pci_bus_realize;
     k->unrealize = pci_bus_unrealize;
     k->reset = pcibus_reset;
+    k->can_add_device = pci_can_add_device;
 
     pbc->is_root = pcibus_is_root;
     pbc->bus_num = pcibus_num;
diff --git a/include/hw/pci/pci_bus.h b/include/hw/pci/pci_bus.h
index 403fec6..02055d4 100644
--- a/include/hw/pci/pci_bus.h
+++ b/include/hw/pci/pci_bus.h
@@ -23,6 +23,7 @@ struct PCIBus {
     PCIIOMMUFunc iommu_fn;
     void *iommu_opaque;
     uint8_t devfn_min;
+    uint8_t devfn_max;
     pci_set_irq_fn set_irq;
     pci_map_irq_fn map_irq;
     pci_route_irq_fn route_intx_to_irq;
-- 
2.5.0