[Qemu-devel] [PATCH] pci_bridge: factor out common code

["Michael S. Tsirkin" <mst@redhat.com>]

Reuse common code in pcie_port, override the hardwired-to-0
bits per PCI Express spec.
No functional change but makes the code easier to follow.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---

Alex, I applied the following on top of your patch and
did a dump of the config space to verify nothing changed.
Could you please also confirm this does not conflict with your vga
assignment work?

 hw/pci/pci.c        | 14 ++++----------
 hw/pci/pci_bridge.h |  7 +++++++
 hw/pci/pcie_port.c  | 22 +++++++++++++---------
 3 files changed, 24 insertions(+), 19 deletions(-)

diff --git a/hw/pci/pci.c b/hw/pci/pci.c
index a881602..8772707 100644
--- a/hw/pci/pci.c
+++ b/hw/pci/pci.c
@@ -668,16 +668,10 @@ static void pci_init_mask_bridge(PCIDevice *d)
     pci_word_test_and_set_mask(d->config + PCI_PREF_MEMORY_LIMIT,
                                PCI_PREF_RANGE_TYPE_64);
 
-/* TODO: add this define to pci_regs.h in linux and then in qemu. */
-#define  PCI_BRIDGE_CTL_VGA_16BIT	0x10	/* VGA 16-bit decode */
-#define  PCI_BRIDGE_CTL_DISCARD		0x100	/* Primary discard timer */
-#define  PCI_BRIDGE_CTL_SEC_DISCARD	0x200	/* Secondary discard timer */
-#define  PCI_BRIDGE_CTL_DISCARD_STATUS	0x400	/* Discard timer status */
-#define  PCI_BRIDGE_CTL_DISCARD_SERR	0x800	/* Discard timer SERR# enable */
-/*
- * TODO: Bridges default to 10-bit VGA decoding but we currently only
- * implement 16-bit decoding (no alias support).
- */
+    /*
+     * TODO: Bridges default to 10-bit VGA decoding but we currently only
+     * implement 16-bit decoding (no alias support).
+     */
     pci_set_word(d->wmask + PCI_BRIDGE_CONTROL,
                  PCI_BRIDGE_CTL_PARITY |
                  PCI_BRIDGE_CTL_SERR |
diff --git a/hw/pci/pci_bridge.h b/hw/pci/pci_bridge.h
index 455cb66..9d25c1b 100644
--- a/hw/pci/pci_bridge.h
+++ b/hw/pci/pci_bridge.h
@@ -55,6 +55,13 @@ void pci_bridge_exitfn(PCIDevice *pci_dev);
 void pci_bridge_map_irq(PCIBridge *br, const char* bus_name,
                         pci_map_irq_fn map_irq);
 
+/* TODO: add this define to pci_regs.h in linux and then in qemu. */
+#define  PCI_BRIDGE_CTL_VGA_16BIT	0x10	/* VGA 16-bit decode */
+#define  PCI_BRIDGE_CTL_DISCARD		0x100	/* Primary discard timer */
+#define  PCI_BRIDGE_CTL_SEC_DISCARD	0x200	/* Secondary discard timer */
+#define  PCI_BRIDGE_CTL_DISCARD_STATUS	0x400	/* Discard timer status */
+#define  PCI_BRIDGE_CTL_DISCARD_SERR	0x800	/* Discard timer SERR# enable */
+
 #endif  /* QEMU_PCI_BRIDGE_H */
 /*
  * Local variables:
diff --git a/hw/pci/pcie_port.c b/hw/pci/pcie_port.c
index 1be107b..5d39a2d 100644
--- a/hw/pci/pcie_port.c
+++ b/hw/pci/pcie_port.c
@@ -27,15 +27,17 @@ void pcie_port_init_reg(PCIDevice *d)
     pci_set_word(d->config + PCI_STATUS, 0);
     pci_set_word(d->config + PCI_SEC_STATUS, 0);
 
-    /* Unlike conventional pci bridge, some bits are hardwired to 0. */
-#define  PCI_BRIDGE_CTL_VGA_16BIT       0x10    /* VGA 16-bit decode */
-    pci_set_word(d->wmask + PCI_BRIDGE_CONTROL,
-                 PCI_BRIDGE_CTL_PARITY |
-                 PCI_BRIDGE_CTL_ISA |
-                 PCI_BRIDGE_CTL_VGA |
-                 PCI_BRIDGE_CTL_VGA_16BIT | /* Req, but no alias support yet */
-                 PCI_BRIDGE_CTL_SERR |
-                 PCI_BRIDGE_CTL_BUS_RESET);
+    /*
+     * Unlike conventional pci bridge, for some bits the spec states:
+     * Does not apply to PCI Express and must be hardwired to 0.
+     */
+    pci_word_test_and_clear_mask(d->wmask + PCI_BRIDGE_CONTROL,
+                                 PCI_BRIDGE_CTL_MASTER_ABORT |
+                                 PCI_BRIDGE_CTL_FAST_BACK |
+                                 PCI_BRIDGE_CTL_DISCARD |
+                                 PCI_BRIDGE_CTL_SEC_DISCARD |
+                                 PCI_BRIDGE_CTL_DISCARD_STATUS |
+                                 PCI_BRIDGE_CTL_DISCARD_SERR);
 }
 
 /**************************************************************************
-- 
MST