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FILE_LICENCE ( GPL2_OR_LATER );
#include <stdint.h>
#include <ipxe/pci.h>
/**
* Look for a PCI capability
*
* @v pci PCI device to query
* @v cap Capability code
* @ret address Address of capability, or 0 if not found
*
* Determine whether or not a device supports a given PCI capability.
* Returns the address of the requested capability structure within
* the device's PCI configuration space, or 0 if the device does not
* support it.
*/
int pci_find_capability ( struct pci_device *pci, int cap ) {
uint16_t status;
uint8_t pos, id;
uint8_t hdr_type;
int ttl = 48;
pci_read_config_word ( pci, PCI_STATUS, &status );
if ( ! ( status & PCI_STATUS_CAP_LIST ) )
return 0;
pci_read_config_byte ( pci, PCI_HEADER_TYPE, &hdr_type );
switch ( hdr_type & 0x7F ) {
case PCI_HEADER_TYPE_NORMAL:
case PCI_HEADER_TYPE_BRIDGE:
default:
pci_read_config_byte ( pci, PCI_CAPABILITY_LIST, &pos );
break;
case PCI_HEADER_TYPE_CARDBUS:
pci_read_config_byte ( pci, PCI_CB_CAPABILITY_LIST, &pos );
break;
}
while ( ttl-- && pos >= 0x40 ) {
pos &= ~3;
pci_read_config_byte ( pci, pos + PCI_CAP_LIST_ID, &id );
DBG ( "PCI Capability: %d\n", id );
if ( id == 0xff )
break;
if ( id == cap )
return pos;
pci_read_config_byte ( pci, pos + PCI_CAP_LIST_NEXT, &pos );
}
return 0;
}
/**
* Find the size of a PCI BAR
*
* @v pci PCI device
* @v reg PCI register number
* @ret size BAR size
*
* It should not be necessary for any Etherboot code to call this
* function.
*/
unsigned long pci_bar_size ( struct pci_device *pci, unsigned int reg ) {
uint16_t cmd;
uint32_t start, size;
/* Save the original command register */
pci_read_config_word ( pci, PCI_COMMAND, &cmd );
/* Save the original bar */
pci_read_config_dword ( pci, reg, &start );
/* Compute which bits can be set */
pci_write_config_dword ( pci, reg, ~0 );
pci_read_config_dword ( pci, reg, &size );
/* Restore the original size */
pci_write_config_dword ( pci, reg, start );
/* Find the significant bits */
/* Restore the original command register. This reenables decoding. */
pci_write_config_word ( pci, PCI_COMMAND, cmd );
if ( start & PCI_BASE_ADDRESS_SPACE_IO ) {
size &= PCI_BASE_ADDRESS_IO_MASK;
} else {
size &= PCI_BASE_ADDRESS_MEM_MASK;
}
/* Find the lowest bit set */
size = size & ~( size - 1 );
return size;
}
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