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Rework the _BBN handling for Host-PCI bridges. Previously we only trusted

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a _BBN value of 0 if it was for the first bridge encountered since some
older systems returned _BBN of 0 for all bridges.  However, some newer
systems enumerate bridges with non-zero _BBN before bus 0 which is
perfectly valid.  Handle both cases by trusting the first bridge that has
a _BBN of 0 and falling back to reading from non-standard config registers
only for subsequent bridges with a _BBN of 0.  We also only perform this
check for segment (domain) 0.  We assume that _BBN is always correct
for segments other than 0.

Tested by:	Josef Moellers  josef.moellers at fujitsu
MFC after:	1 week
This commit is contained in:
John Baldwin 2009-06-09 13:44:17 +00:00
parent 3e7865bcfc
commit 0668724b99
1 changed files with 25 additions and 18 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

43
sys/dev/acpica/acpi_pcib_acpi.c
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@ -148,6 +148,7 @@ acpi_pcib_acpi_attach(device_t dev)
{
struct acpi_hpcib_softc *sc;
ACPI_STATUS status;
static int bus0_seen = 0;
u_int addr, slot, func, busok;
uint8_t busno;
@ -157,6 +158,21 @@ acpi_pcib_acpi_attach(device_t dev)
sc->ap_dev = dev;
sc->ap_handle = acpi_get_handle(dev);
/*
* Get our segment number by evaluating _SEG
* It's OK for this to not exist.
*/
status = acpi_GetInteger(sc->ap_handle, "_SEG", &sc->ap_segment);
if (ACPI_FAILURE(status)) {
if (status != AE_NOT_FOUND) {
device_printf(dev, "could not evaluate _SEG - %s\n",
AcpiFormatException(status));
return_VALUE (ENXIO);
}
/* If it's not found, assume 0. */
sc->ap_segment = 0;
}
/*
* Get our base bus number by evaluating _BBN.
* If this doesn't work, we assume we're bus number 0.
@ -171,8 +187,10 @@ acpi_pcib_acpi_attach(device_t dev)
* XXX invoke _REG on this for the PCI config space address space?
* XXX It seems many BIOS's with multiple Host-PCI bridges do not set
* _BBN correctly. They set _BBN to zero for all bridges. Thus,
* if _BBN is zero and pcib0 already exists, we try to read our
* if _BBN is zero and PCI bus 0 already exists, we try to read our
* bus number from the configuration registers at address _ADR.
* We only do this for domain/segment 0 in the hopes that this is
* only needed for old single-domain machines.
*/
status = acpi_GetInteger(sc->ap_handle, "_BBN", &sc->ap_bus);
if (ACPI_FAILURE(status)) {
@ -187,11 +205,11 @@ acpi_pcib_acpi_attach(device_t dev)
}
/*
* If the bus is zero and pcib0 already exists, read the bus number
* via PCI config space.
* If this is segment 0, the bus is zero, and PCI bus 0 already
* exists, read the bus number via PCI config space.
*/
busok = 1;
if (sc->ap_bus == 0 && devclass_get_device(pcib_devclass, 0) != dev) {
if (sc->ap_segment == 0 && sc->ap_bus == 0 && bus0_seen) {
busok = 0;
status = acpi_GetInteger(sc->ap_handle, "_ADR", &addr);
if (ACPI_FAILURE(status)) {
@ -228,20 +246,9 @@ acpi_pcib_acpi_attach(device_t dev)
device_printf(dev, "trying bus number %d\n", sc->ap_bus);
}
/*
* Get our segment number by evaluating _SEG
* It's OK for this to not exist.
*/
status = acpi_GetInteger(sc->ap_handle, "_SEG", &sc->ap_segment);
if (ACPI_FAILURE(status)) {
if (status != AE_NOT_FOUND) {
device_printf(dev, "could not evaluate _SEG - %s\n",
AcpiFormatException(status));
return_VALUE (ENXIO);
}
/* If it's not found, assume 0. */
sc->ap_segment = 0;
}
/* If this is bus 0 on segment 0, note that it has been seen already. */
if (sc->ap_segment == 0 && sc->ap_bus == 0)
bus0_seen = 1;
return (acpi_pcib_attach(dev, &sc->ap_prt, sc->ap_bus));
}