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/******************************************************************************
* pci.c
*
* Architecture-independent PCI access functions.
*/
#include <xen/pci.h>
#include <xen/pci_regs.h>
int pci_find_cap_offset(u16 seg, u8 bus, u8 dev, u8 func, u8 cap)
{
u8 id;
int max_cap = 48;
u8 pos = PCI_CAPABILITY_LIST;
u16 status;
status = pci_conf_read16(seg, bus, dev, func, PCI_STATUS);
if ( (status & PCI_STATUS_CAP_LIST) == 0 )
return 0;
while ( max_cap-- )
{
pos = pci_conf_read8(seg, bus, dev, func, pos);
if ( pos < 0x40 )
break;
pos &= ~3;
id = pci_conf_read8(seg, bus, dev, func, pos + PCI_CAP_LIST_ID);
if ( id == 0xff )
break;
else if ( id == cap )
return pos;
pos += PCI_CAP_LIST_NEXT;
}
return 0;
}
int pci_find_next_cap(u16 seg, u8 bus, unsigned int devfn, u8 pos, int cap)
{
u8 id;
int ttl = 48;
while ( ttl-- )
{
pos = pci_conf_read8(seg, bus, PCI_SLOT(devfn), PCI_FUNC(devfn), pos);
if ( pos < 0x40 )
break;
pos &= ~3;
id = pci_conf_read8(seg, bus, PCI_SLOT(devfn), PCI_FUNC(devfn),
pos + PCI_CAP_LIST_ID);
if ( id == 0xff )
break;
if ( id == cap )
return pos;
pos += PCI_CAP_LIST_NEXT;
}
return 0;
}
/**
* pci_find_ext_capability - Find an extended capability
* @dev: PCI device to query
* @cap: capability code
*
* Returns the address of the requested extended capability structure
* within the device's PCI configuration space or 0 if the device does
* not support it. Possible values for @cap:
*
* %PCI_EXT_CAP_ID_ERR Advanced Error Reporting
* %PCI_EXT_CAP_ID_VC Virtual Channel
* %PCI_EXT_CAP_ID_DSN Device Serial Number
* %PCI_EXT_CAP_ID_PWR Power Budgeting
*/
int pci_find_ext_capability(int seg, int bus, int devfn, int cap)
{
u32 header;
int ttl = 480; /* 3840 bytes, minimum 8 bytes per capability */
int pos = 0x100;
header = pci_conf_read32(seg, bus, PCI_SLOT(devfn), PCI_FUNC(devfn), pos);
/*
* If we have no capabilities, this is indicated by cap ID,
* cap version and next pointer all being 0.
*/
if ( (header == 0) || (header == -1) )
return 0;
while ( ttl-- > 0 ) {
if ( PCI_EXT_CAP_ID(header) == cap )
return pos;
pos = PCI_EXT_CAP_NEXT(header);
if ( pos < 0x100 )
break;
header = pci_conf_read32(seg, bus, PCI_SLOT(devfn), PCI_FUNC(devfn), pos);
}
return 0;
}
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