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x86: clean up vSMP detection 

vSMP detection: access pci config space early in boot to detect if the
system is a vSMPowered box, and cache the result in a flag, so that
is_vsmp_box() retrieves the value of the flag always.

Signed-off-by: Ravikiran Thirumalai <kiran@scalex86.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Ravikiran G Thirumalai 2008-03-24 14:48:36 -07:00 committed by Ingo Molnar
parent 43cdf5d6e0
commit e5699a8231
1 changed files with 24 additions and 14 deletions
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38
arch/x86/kernel/vsmp_64.c
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@ -108,25 +108,34 @@ static void __init set_vsmp_pv_ops(void)
#endif
#ifdef CONFIG_PCI
static int vsmp = -1;
static int is_vsmp = -1;
static void __init detect_vsmp_box(void)
{
is_vsmp = 0;
if (!early_pci_allowed())
return;
/* Check if we are running on a ScaleMP vSMPowered box */
if (read_pci_config(0, 0x1f, 0, PCI_VENDOR_ID) ==
(PCI_VENDOR_ID_SCALEMP | (PCI_DEVICE_ID_SCALEMP_VSMP_CTL << 16)))
is_vsmp = 1;
}
int is_vsmp_box(void)
{
if (vsmp != -1)
return vsmp;
vsmp = 0;
if (!early_pci_allowed())
return vsmp;
/* Check if we are running on a ScaleMP vSMP box */
if (read_pci_config(0, 0x1f, 0, PCI_VENDOR_ID) ==
(PCI_VENDOR_ID_SCALEMP | (PCI_DEVICE_ID_SCALEMP_VSMP_CTL << 16)))
vsmp = 1;
return vsmp;
if (is_vsmp != -1)
return is_vsmp;
else {
WARN_ON_ONCE(1);
return 0;
}
}
#else
static int __init detect_vsmp_box(void)
{
}
int is_vsmp_box(void)
{
return 0;
@ -135,6 +144,7 @@ int is_vsmp_box(void)
void __init vsmp_init(void)
{
detect_vsmp_box();
if (!is_vsmp_box())
return;