The Intel 82426EX ISA Bridge (IB), a part of the Intel 82420EX PCIset,
implements PCI interrupt steering with a PIRQ router in the form of two
PIRQ Route Control registers, available in the PCI configuration space
at locations 0x66 and 0x67 for the PIRQ0# and PIRQ1# lines respectively.
The semantics is the same as with the PIIX router, however it is not
clear if BIOSes use register indices or line numbers as the cookie to
identify PCI interrupts in their routing tables and therefore support
either scheme.
The IB is directly attached to the Intel 82425EX PCI System Controller
(PSC) component of the chipset via a dedicated PSC/IB Link interface
rather than the host bus or PCI. Therefore it does not itself appear in
the PCI configuration space even though it responds to configuration
cycles addressing registers it implements. Use 82425EX's identification
then for determining the presence of the IB.
References:
[1] "82420EX PCIset Data Sheet, 82425EX PCI System Controller (PSC) and
82426EX ISA Bridge (IB)", Intel Corporation, Order Number:
290488-004, December 1995, Section 3.3.18 "PIRQ1RC/PIRQ0RC--PIRQ
Route Control Registers", p. 61
Signed-off-by: Maciej W. Rozycki <macro@xxxxxxxxxxx>
---
arch/x86/pci/irq.c | 49 ++++++++++++++++++++++++++++++++++++++++++++++++
include/linux/pci_ids.h | 1
2 files changed, 50 insertions(+)
linux-x86-pirq-router-ib.diff
Index: linux-macro-pirq/arch/x86/pci/irq.c
===================================================================
--- linux-macro-pirq.orig/arch/x86/pci/irq.c
+++ linux-macro-pirq/arch/x86/pci/irq.c
@@ -447,6 +447,50 @@ static int pirq_piix_set(struct pci_dev
}
/*
+ * PIRQ routing for the 82426EX ISA Bridge (IB) ASIC used with the
+ * Intel 82420EX PCIset.
+ *
+ * There are only two PIRQ Route Control registers, available in the
+ * combined 82425EX/82426EX PCI configuration space, at 0x66 and 0x67
+ * for the PIRQ0# and PIRQ1# lines respectively. The semantics is
+ * the same as with the PIIX router.
+ *
+ * References:
+ *
+ * "82420EX PCIset Data Sheet, 82425EX PCI System Controller (PSC)
+ * and 82426EX ISA Bridge (IB)", Intel Corporation, Order Number:
+ * 290488-004, December 1995
+ */
+
+#define PCI_I82426EX_PIRQ_ROUTE_CONTROL 0x66u
+
+static int pirq_ib_get(struct pci_dev *router, struct pci_dev *dev, int pirq)
+{
+ int reg;
+ u8 x;
+
+ reg = pirq;
+ if (reg >= 1 && reg <= 2)
+ reg += PCI_I82426EX_PIRQ_ROUTE_CONTROL - 1;
+
+ pci_read_config_byte(router, reg, &x);
+ return (x < 16) ? x : 0;
+}
+
+static int pirq_ib_set(struct pci_dev *router, struct pci_dev *dev, int pirq,
+ int irq)
+{
+ int reg;
+
+ reg = pirq;
+ if (reg >= 1 && reg <= 2)
+ reg += PCI_I82426EX_PIRQ_ROUTE_CONTROL - 1;
+
+ pci_write_config_byte(router, reg, irq);
+ return 1;
+}
+
+/*
* The VIA pirq rules are nibble-based, like ALI,
* but without the ugly irq number munging.
* However, PIRQD is in the upper instead of lower 4 bits.
@@ -892,6 +936,11 @@ static __init int intel_router_probe(str
r->get = pirq_piix_get;
r->set = pirq_piix_set;
return 1;
+ case PCI_DEVICE_ID_INTEL_82425:
+ r->name = "PSC/IB";
+ r->get = pirq_ib_get;
+ r->set = pirq_ib_set;
+ return 1;
}
if ((device >= PCI_DEVICE_ID_INTEL_5_3400_SERIES_LPC_MIN &&
Index: linux-macro-pirq/include/linux/pci_ids.h
===================================================================
--- linux-macro-pirq.orig/include/linux/pci_ids.h
+++ linux-macro-pirq/include/linux/pci_ids.h
@@ -2644,6 +2644,7 @@
#define PCI_DEVICE_ID_INTEL_82375 0x0482
#define PCI_DEVICE_ID_INTEL_82424 0x0483
#define PCI_DEVICE_ID_INTEL_82378 0x0484
+#define PCI_DEVICE_ID_INTEL_82425 0x0486
#define PCI_DEVICE_ID_INTEL_MRST_SD0 0x0807
#define PCI_DEVICE_ID_INTEL_MRST_SD1 0x0808
#define PCI_DEVICE_ID_INTEL_MFD_SD 0x0820
