pci: prepare irq code for interrupt state

This rearranges code in preparation for interrupt state
implementation.
Changes:
	- split up bus walk away from interrupt handling
          into a subroutine
	- change irq_state from an array to bitmask
	- verify that irq_state values are 0 or 1 on load

There are no functional changes.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Isaku Yamahata <yamahata@valinux.co.jp>

2 files changed, 74 insertions, 17 deletions

diff --git a/hw/pci.c b/hw/pci.c
index f2b6cff38c..a0df618e53 100644
--- a/hw/pci.c
+++ b/hw/pci.c
@@ -103,11 +103,36 @@ static int pci_bar(PCIDevice *d, int reg)
     return type == PCI_HEADER_TYPE_BRIDGE ? PCI_ROM_ADDRESS1 : PCI_ROM_ADDRESS;
 }
 
+static inline int pci_irq_state(PCIDevice *d, int irq_num)
+{
+	return (d->irq_state >> irq_num) & 0x1;
+}
+
+static inline void pci_set_irq_state(PCIDevice *d, int irq_num, int level)
+{
+	d->irq_state &= ~(0x1 << irq_num);
+	d->irq_state |= level << irq_num;
+}
+
+static void pci_change_irq_level(PCIDevice *pci_dev, int irq_num, int change)
+{
+    PCIBus *bus;
+    for (;;) {
+        bus = pci_dev->bus;
+        irq_num = bus->map_irq(pci_dev, irq_num);
+        if (bus->set_irq)
+            break;
+        pci_dev = bus->parent_dev;
+    }
+    bus->irq_count[irq_num] += change;
+    bus->set_irq(bus->irq_opaque, irq_num, bus->irq_count[irq_num] != 0);
+}
+
 static void pci_device_reset(PCIDevice *dev)
 {
     int r;
 
-    memset(dev->irq_state, 0, sizeof dev->irq_state);
+    dev->irq_state = 0;
     dev->config[PCI_COMMAND] &= ~(PCI_COMMAND_IO | PCI_COMMAND_MEMORY |
                                   PCI_COMMAND_MASTER);
     dev->config[PCI_CACHE_LINE_SIZE] = 0x0;
@@ -274,6 +299,43 @@ static VMStateInfo vmstate_info_pci_config = {
     .put  = put_pci_config_device,
 };
 
+static int get_pci_irq_state(QEMUFile *f, void *pv, size_t size)
+{
+    PCIDevice *s = container_of(pv, PCIDevice, config);
+    uint32_t irq_state[PCI_NUM_PINS];
+    int i;
+    for (i = 0; i < PCI_NUM_PINS; ++i) {
+        irq_state[i] = qemu_get_be32(f);
+        if (irq_state[i] != 0x1 && irq_state[i] != 0) {
+            fprintf(stderr, "irq state %d: must be 0 or 1.\n",
+                    irq_state[i]);
+            return -EINVAL;
+        }
+    }
+
+    for (i = 0; i < PCI_NUM_PINS; ++i) {
+        pci_set_irq_state(s, i, irq_state[i]);
+    }
+
+    return 0;
+}
+
+static void put_pci_irq_state(QEMUFile *f, void *pv, size_t size)
+{
+    int i;
+    PCIDevice *s = container_of(pv, PCIDevice, config);
+
+    for (i = 0; i < PCI_NUM_PINS; ++i) {
+        qemu_put_be32(f, pci_irq_state(s, i));
+    }
+}
+
+static VMStateInfo vmstate_info_pci_irq_state = {
+    .name = "pci irq state",
+    .get  = get_pci_irq_state,
+    .put  = put_pci_irq_state,
+};
+
 const VMStateDescription vmstate_pci_device = {
     .name = "PCIDevice",
     .version_id = 2,
@@ -284,7 +346,9 @@ const VMStateDescription vmstate_pci_device = {
         VMSTATE_BUFFER_UNSAFE_INFO(config, PCIDevice, 0,
                                    vmstate_info_pci_config,
                                    PCI_CONFIG_SPACE_SIZE),
-        VMSTATE_INT32_ARRAY_V(irq_state, PCIDevice, PCI_NUM_PINS, 2),
+        VMSTATE_BUFFER_UNSAFE_INFO(irq_state, PCIDevice, 2,
+				   vmstate_info_pci_irq_state,
+				   PCI_NUM_PINS * sizeof(int32_t)),
         VMSTATE_END_OF_LIST()
     }
 };
@@ -299,7 +363,9 @@ const VMStateDescription vmstate_pcie_device = {
         VMSTATE_BUFFER_UNSAFE_INFO(config, PCIDevice, 0,
                                    vmstate_info_pci_config,
                                    PCIE_CONFIG_SPACE_SIZE),
-        VMSTATE_INT32_ARRAY_V(irq_state, PCIDevice, PCI_NUM_PINS, 2),
+        VMSTATE_BUFFER_UNSAFE_INFO(irq_state, PCIDevice, 2,
+				   vmstate_info_pci_irq_state,
+				   PCI_NUM_PINS * sizeof(int32_t)),
         VMSTATE_END_OF_LIST()
     }
 };
@@ -499,7 +565,7 @@ static PCIDevice *do_pci_register_device(PCIDevice *pci_dev, PCIBus *bus,
     pci_dev->bus = bus;
     pci_dev->devfn = devfn;
     pstrcpy(pci_dev->name, sizeof(pci_dev->name), name);
-    memset(pci_dev->irq_state, 0, sizeof(pci_dev->irq_state));
+    pci_dev->irq_state = 0;
     pci_config_alloc(pci_dev);
 
     header_type &= ~PCI_HEADER_TYPE_MULTI_FUNCTION;
@@ -882,23 +948,14 @@ void pci_default_write_config(PCIDevice *d, uint32_t addr, uint32_t val, int l)
 static void pci_set_irq(void *opaque, int irq_num, int level)
 {
     PCIDevice *pci_dev = opaque;
-    PCIBus *bus;
     int change;
 
-    change = level - pci_dev->irq_state[irq_num];
+    change = level - pci_irq_state(pci_dev, irq_num);
     if (!change)
         return;
 
-    pci_dev->irq_state[irq_num] = level;
-    for (;;) {
-        bus = pci_dev->bus;
-        irq_num = bus->map_irq(pci_dev, irq_num);
-        if (bus->set_irq)
-            break;
-        pci_dev = bus->parent_dev;
-    }
-    bus->irq_count[irq_num] += change;
-    bus->set_irq(bus->irq_opaque, irq_num, bus->irq_count[irq_num] != 0);
+    pci_set_irq_state(pci_dev, irq_num, level);
+    pci_change_irq_level(pci_dev, irq_num, change);
 }
 
 /***********************************************************/
diff --git a/hw/pci.h b/hw/pci.h
index 3e8abad222..ebf6c39d52 100644
--- a/hw/pci.h
+++ b/hw/pci.h
@@ -220,7 +220,7 @@ struct PCIDevice {
     qemu_irq *irq;
 
     /* Current IRQ levels.  Used internally by the generic PCI code.  */
-    int irq_state[PCI_NUM_PINS];
+    uint8_t irq_state;
 
     /* Capability bits */
     uint32_t cap_present;