[efi] Do not attempt to drive PCI bridge devices
The "bridge" driver introduced in 3aa6b79 ("[pci] Add minimal PCI
bridge driver") is required only for BIOS builds using the ENA driver,
where experimentation shows that we cannot rely on the BIOS to fully
assign MMIO addresses.
Since the driver is a valid PCI driver, it will end up binding to all
PCI bridge devices even on a UEFI platform, where the firmware is
likely to have completed MMIO address assignment correctly. This has
no impact on most systems since there is generally no UEFI driver for
PCI bridges: the enumeration of the whole PCI bus is handled by the
PciBusDxe driver bound to the root bridge.
Experimentation shows that at least one laptop will freeze at the
point that iPXE attempts to bind to the bridge device. No deeper
investigation has been carried out to find the root cause.
Fix by causing efipci_supported() to return an error unless the
configuration space header type indicates a non-bridge device.
Reported-by: Marcel Petersen <mp@sbe.de>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
diff --git a/src/drivers/bus/pci.c b/src/drivers/bus/pci.c
index 7953aae..92b3896 100644
--- a/src/drivers/bus/pci.c
+++ b/src/drivers/bus/pci.c
@@ -205,6 +205,7 @@
pci_read_config_dword ( pci, PCI_REVISION, &tmp );
pci->class = ( tmp >> 8 );
pci_read_config_byte ( pci, PCI_INTERRUPT_LINE, &pci->irq );
+ pci_read_config_byte ( pci, PCI_HEADER_TYPE, &pci->hdrtype );
pci_read_bases ( pci );
/* Initialise generic device component */
diff --git a/src/include/ipxe/pci.h b/src/include/ipxe/pci.h
index 637b20d..8c6d9e4 100644
--- a/src/include/ipxe/pci.h
+++ b/src/include/ipxe/pci.h
@@ -227,6 +227,8 @@
uint32_t class;
/** Interrupt number */
uint8_t irq;
+ /** Header type */
+ uint8_t hdrtype;
/** Segment, bus, device, and function (bus:dev.fn) number */
uint32_t busdevfn;
/** Driver for this device */
diff --git a/src/interface/efi/efi_pci.c b/src/interface/efi/efi_pci.c
index 4796201..e2eeeb3 100644
--- a/src/interface/efi/efi_pci.c
+++ b/src/interface/efi/efi_pci.c
@@ -785,12 +785,22 @@
*/
static int efipci_supported ( EFI_HANDLE device ) {
struct efi_pci_device efipci;
+ uint8_t hdrtype;
int rc;
/* Get PCI device information */
if ( ( rc = efipci_info ( device, &efipci ) ) != 0 )
return rc;
+ /* Do not attempt to drive bridges */
+ hdrtype = efipci.pci.hdrtype;
+ if ( ( hdrtype & PCI_HEADER_TYPE_MASK ) != PCI_HEADER_TYPE_NORMAL ) {
+ DBGC ( device, "EFIPCI " PCI_FMT " type %02x is not type %02x\n",
+ PCI_ARGS ( &efipci.pci ), hdrtype,
+ PCI_HEADER_TYPE_NORMAL );
+ return -ENOTTY;
+ }
+
/* Look for a driver */
if ( ( rc = pci_find_driver ( &efipci.pci ) ) != 0 ) {
DBGC ( device, "EFIPCI " PCI_FMT " (%04x:%04x class %06x) "
