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[pci] Add pci_find_next_capability() 

PCI devices may support more capabilities of the same type (for
example PCI_CAP_ID_VNDR) and there was no way to discover all of them.
This commit adds a new API pci_find_next_capability which provides
this functionality.  It would typically be used like so:

  for (pos = pci_find_capability(pci, PCI_CAP_ID_VNDR);
       pos > 0;
       pos = pci_find_next_capability(pci, pos, PCI_CAP_ID_VNDR)) {
    ...
  }

Signed-off-by: Ladi Prosek <lprosek@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
This commit is contained in:
Ladi Prosek 2016-04-11 11:26:56 +02:00 committed by Michael Brown
parent 5e5450c2d0
commit 2379494918
2 changed files with 43 additions and 13 deletions
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54
src/drivers/bus/pciextra.c
View File

@ -3,6 +3,24 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
#include <stdint.h>
#include <ipxe/pci.h>
static int pci_find_capability_common ( struct pci_device *pci,
uint8_t pos, int cap ) {
uint8_t id;
int ttl = 48;
while ( ttl-- && pos >= 0x40 ) {
pos &= ~3;
pci_read_config_byte ( pci, pos + PCI_CAP_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_NEXT, &pos );
}
return 0;
}
/**
* Look for a PCI capability
*
@ -17,9 +35,8 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
*/
int pci_find_capability ( struct pci_device *pci, int cap ) {
uint16_t status;
uint8_t pos, id;
uint8_t pos;
uint8_t hdr_type;
int ttl = 48;
pci_read_config_word ( pci, PCI_STATUS, &status );
if ( ! ( status & PCI_STATUS_CAP_LIST ) )
@ -36,17 +53,28 @@ int pci_find_capability ( struct pci_device *pci, int cap ) {
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_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_NEXT, &pos );
}
return 0;
return pci_find_capability_common ( pci, pos, cap );
}
/**
* Look for another PCI capability
*
* @v pci PCI device to query
* @v pos Address of the current capability
* @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
* starting the search at a given address within the device's PCI
* configuration space. Returns the address of the next capability
* structure within the device's PCI configuration space, or 0 if the
* device does not support another such capability.
*/
int pci_find_next_capability ( struct pci_device *pci, int pos, int cap ) {
uint8_t new_pos;
pci_read_config_byte ( pci, pos + PCI_CAP_NEXT, &new_pos );
return pci_find_capability_common ( pci, new_pos, cap );
}
/**

2
src/include/ipxe/pci.h
View File

@ -286,6 +286,8 @@ extern int pci_find_driver ( struct pci_device *pci );
extern int pci_probe ( struct pci_device *pci );
extern void pci_remove ( struct pci_device *pci );
extern int pci_find_capability ( struct pci_device *pci, int capability );
extern int pci_find_next_capability ( struct pci_device *pci,
int pos, int capability );
extern unsigned long pci_bar_size ( struct pci_device *pci, unsigned int reg );
/**