Hi,
While working on the SiS85C497 PIRQ router I have noticed an odd
phenomenon with my venerable Tyan Tomcat IV S1564D board, where the PCI
INTD# line of the USB host controller included as function 3 of the PIIX3
southbridge cannot be routed in the `noapic' mode. As it turns out the
reason for this is the BIOS has two individual entries in its PIRQ table
for two of its three functions, and the wrong one is chosen for routing
said line.
Strictly speaking this violates the PCI BIOS specification, but it can be
easily worked around while preserving the semantics for compliant systems.
Therefore I have come up with this patch series, which addresses this
problem with 3/3, adds function reporting to the debug PIRQ table dump
with 2/3 and also prints a usable physical memory address of the PIRQ
table in a debug message with 1/3.
See individual change descriptions for further details.
Please apply.
Maciej
It makes no sense to hide the address of the $PIR table in a debug dump:
PCI: Interrupt Routing Table found at 0x(ptrval)
let alone print its virtual address, given that this is a BIOS entity at
a fixed location in the system's memory map. Show the physical address
instead then, e.g.:
PCI: Interrupt Routing Table found at 0xfde10
Signed-off-by: Maciej W. Rozycki <[email protected]>
---
arch/x86/pci/irq.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
linux-x86-debug-pirq-addr.diff
Index: linux-macro-ide/arch/x86/pci/irq.c
===================================================================
--- linux-macro-ide.orig/arch/x86/pci/irq.c
+++ linux-macro-ide/arch/x86/pci/irq.c
@@ -78,8 +78,8 @@ static inline struct irq_routing_table *
for (i = 0; i < rt->size; i++)
sum += addr[i];
if (!sum) {
- DBG(KERN_DEBUG "PCI: Interrupt Routing Table found at 0x%p\n",
- rt);
+ DBG(KERN_DEBUG "PCI: Interrupt Routing Table found at 0x%lx\n",
+ __pa(rt));
return rt;
}
return NULL;
Contrary to the PCI BIOS specification[1] some systems include the PCI
function number for motherboard devices in their $PIR table, e.g. this
is what the Tyan Tomcat IV S1564D board reports:
00:14 slot=01
0:60/deb8
1:61/deb8
2:62/deb8
3:63/deb8
00:13 slot=02
0:61/deb8
1:62/deb8
2:63/deb8
3:60/deb8
00:12 slot=03
0:62/deb8
1:63/deb8
2:60/deb8
3:61/deb8
00:11 slot=04
0:63/deb8
1:60/deb8
2:61/deb8
3:62/deb8
00:07 slot=00
0:00/deb8
1:00/deb8
2:00/deb8
3:00/deb8
00:07 slot=00
0:00/deb8
1:00/deb8
2:00/deb8
3:63/deb8
Print the function number then in the debug $PIR table dump:
00:14.0 slot=01
0:60/deb8
1:61/deb8
2:62/deb8
3:63/deb8
00:13.0 slot=02
0:61/deb8
1:62/deb8
2:63/deb8
3:60/deb8
00:12.0 slot=03
0:62/deb8
1:63/deb8
2:60/deb8
3:61/deb8
00:11.0 slot=04
0:63/deb8
1:60/deb8
2:61/deb8
3:62/deb8
00:07.1 slot=00
0:00/deb8
1:00/deb8
2:00/deb8
3:00/deb8
00:07.2 slot=00
0:00/deb8
1:00/deb8
2:00/deb8
3:63/deb8
References:
[1] "PCI BIOS Specification", Revision 2.1, PCI Special Interest Group,
August 26, 1994, Table 4-1 "Layout of IRQ routing table entry.", p.
12
Signed-off-by: Maciej W. Rozycki <[email protected]>
---
arch/x86/pci/irq.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
linux-x86-debug-pirq-fn.diff
Index: linux-macro-ide/arch/x86/pci/irq.c
===================================================================
--- linux-macro-ide.orig/arch/x86/pci/irq.c
+++ linux-macro-ide/arch/x86/pci/irq.c
@@ -129,7 +129,8 @@ static void __init pirq_peer_trick(void)
#ifdef DEBUG
{
int j;
- DBG(KERN_DEBUG "%02x:%02x slot=%02x", e->bus, e->devfn/8, e->slot);
+ DBG(KERN_DEBUG "%02x:%02x.%x slot=%02x",
+ e->bus, e->devfn / 8, e->devfn % 8, e->slot);
for (j = 0; j < 4; j++)
DBG(" %d:%02x/%04x", j, e->irq[j].link, e->irq[j].bitmap);
DBG("\n");
Contrary to the PCI BIOS specification[1] some systems include the PCI
function number for onboard devices in their $PIR table. Consequently
the wrong entry can be matched leading to interrupt routing failures.
For example the Tyan Tomcat IV S1564D board has:
00:07.1 slot=00
0:00/deb8
1:00/deb8
2:00/deb8
3:00/deb8
00:07.2 slot=00
0:00/deb8
1:00/deb8
2:00/deb8
3:63/deb8
for its IDE interface and USB controller functions of the 82371SB PIIX3
southbridge. Consequently the first entry matches causing the inability
to route the USB interrupt in the `noapic' mode, in which case we need
to rely on the interrupt line set by the BIOS:
uhci_hcd 0000:00:07.2: runtime IRQ mapping not provided by arch
uhci_hcd 0000:00:07.2: PCI INT D not routed
uhci_hcd 0000:00:07.2: enabling bus mastering
uhci_hcd 0000:00:07.2: UHCI Host Controller
uhci_hcd 0000:00:07.2: new USB bus registered, assigned bus number 1
uhci_hcd 0000:00:07.2: irq 11, io base 0x00006000
Try to match the PCI device and function combined then and if that fails
move on to PCI device matching only. Compliant systems will only have a
single $PIR table entry per PCI device, so this update does not change
the semantics with them, while systems that have several entries for
individual functions of a single PCI device each will match the correct
entry:
uhci_hcd 0000:00:07.2: runtime IRQ mapping not provided by arch
uhci_hcd 0000:00:07.2: PCI INT D -> PIRQ 63, mask deb8, excl 0c20
uhci_hcd 0000:00:07.2: PCI INT D -> newirq 11
uhci_hcd 0000:00:07.2: found PCI INT D -> IRQ 11
uhci_hcd 0000:00:07.2: sharing IRQ 11 with 0000:00:11.0
uhci_hcd 0000:00:07.2: enabling bus mastering
uhci_hcd 0000:00:07.2: UHCI Host Controller
uhci_hcd 0000:00:07.2: new USB bus registered, assigned bus number 1
uhci_hcd 0000:00:07.2: irq 11, io base 0x00006000
[1] "PCI BIOS Specification", Revision 2.1, PCI Special Interest Group,
August 26, 1994, Table 4-1 "Layout of IRQ routing table entry.", p.
12
Signed-off-by: Maciej W. Rozycki <[email protected]>
---
arch/x86/pci/irq.c | 19 +++++++++++++++----
1 file changed, 15 insertions(+), 4 deletions(-)
linux-x86-pirq-fn.diff
Index: linux-macro-ide/arch/x86/pci/irq.c
===================================================================
--- linux-macro-ide.orig/arch/x86/pci/irq.c
+++ linux-macro-ide/arch/x86/pci/irq.c
@@ -948,18 +948,29 @@ static void __init pirq_find_router(stru
/* The device remains referenced for the kernel lifetime */
}
+/*
+ * We're supposed to match on the PCI device only and not the function,
+ * but some BIOSes build their tables with the PCI function included
+ * for motherboard devices, so if a complete match is found, then give
+ * it precedence over a slot match.
+ */
static struct irq_info *pirq_get_info(struct pci_dev *dev)
{
struct irq_routing_table *rt = pirq_table;
int entries = (rt->size - sizeof(struct irq_routing_table)) /
sizeof(struct irq_info);
+ struct irq_info *slotinfo = NULL;
struct irq_info *info;
for (info = rt->slots; entries--; info++)
- if (info->bus == dev->bus->number &&
- PCI_SLOT(info->devfn) == PCI_SLOT(dev->devfn))
- return info;
- return NULL;
+ if (info->bus == dev->bus->number) {
+ if (info->devfn == dev->devfn)
+ return info;
+ if (!slotinfo &&
+ PCI_SLOT(info->devfn) == PCI_SLOT(dev->devfn))
+ slotinfo = info;
+ }
+ return slotinfo;
}
static int pcibios_lookup_irq(struct pci_dev *dev, int assign)