[pci] Generalise pci_num_bus() to pci_discover()

Allow pci_find_next() to discover devices beyond the first PCI
segment, by generalising pci_num_bus() (which implicitly assumes that
there is only a single PCI segment) with pci_discover() (which has the
ability to return an arbitrary contiguous chunk of PCI bus:dev.fn
address space).

Signed-off-by: Michael Brown <mcb30@ipxe.org>

3 files changed, 19 insertions, 11 deletions

diff --git a/src/arch/x86/core/pcidirect.c b/src/arch/x86/core/pcidirect.c
index 9b8226fea..88db90499 100644
--- a/src/arch/x86/core/pcidirect.c
+++ b/src/arch/x86/core/pcidirect.c
@@ -45,7 +45,7 @@ void pcidirect_prepare ( struct pci_device *pci, int where ) {
 	       PCIDIRECT_CONFIG_ADDRESS );
 }
 
-PROVIDE_PCIAPI_INLINE ( direct, pci_num_bus );
+PROVIDE_PCIAPI_INLINE ( direct, pci_discover );
 PROVIDE_PCIAPI_INLINE ( direct, pci_read_config_byte );
 PROVIDE_PCIAPI_INLINE ( direct, pci_read_config_word );
 PROVIDE_PCIAPI_INLINE ( direct, pci_read_config_dword );
diff --git a/src/arch/x86/include/ipxe/pcidirect.h b/src/arch/x86/include/ipxe/pcidirect.h
index decdc8100..394edb2b8 100644
--- a/src/arch/x86/include/ipxe/pcidirect.h
+++ b/src/arch/x86/include/ipxe/pcidirect.h
@@ -26,14 +26,18 @@ struct pci_device;
 extern void pcidirect_prepare ( struct pci_device *pci, int where );
 
 /**
- * Determine number of PCI buses within system
+ * Find next PCI bus:dev.fn address range in system
  *
- * @ret num_bus		Number of buses
+ * @v busdevfn		Starting PCI bus:dev.fn address
+ * @v range		PCI bus:dev.fn address range to fill in
  */
-static inline __always_inline int
-PCIAPI_INLINE ( direct, pci_num_bus ) ( void ) {
+static inline __always_inline void
+PCIAPI_INLINE ( direct, pci_discover ) ( uint32_t busdevfn __unused,
+					 struct pci_range *range ) {
+
 	/* Scan first bus and rely on bridge detection to find higher buses */
-	return 1;
+	range->start = PCI_BUSDEVFN ( 0, 0, 0, 0 );
+	range->count = PCI_BUSDEVFN ( 0, 1, 0, 0 );
 }
 
 /**
diff --git a/src/arch/x86/interface/pcbios/pcibios.c b/src/arch/x86/interface/pcbios/pcibios.c
index bf812f77f..cf818630a 100644
--- a/src/arch/x86/interface/pcbios/pcibios.c
+++ b/src/arch/x86/interface/pcbios/pcibios.c
@@ -34,11 +34,13 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
  */
 
 /**
- * Determine number of PCI buses within system
+ * Find next PCI bus:dev.fn address range in system
  *
- * @ret num_bus		Number of buses
+ * @v busdevfn		Starting PCI bus:dev.fn address
+ * @v range		PCI bus:dev.fn address range to fill in
  */
-static int pcibios_num_bus ( void ) {
+static void pcibios_discover ( uint32_t busdevfn __unused,
+			       struct pci_range *range ) {
 	int discard_a, discard_D;
 	uint8_t max_bus;
 
@@ -57,7 +59,9 @@ static int pcibios_num_bus ( void ) {
 				 "D" ( 0 )
 			       : "ebx", "edx" );
 
-	return ( max_bus + 1 );
+	/* Populate range */
+	range->start = PCI_BUSDEVFN ( 0, 0, 0, 0 );
+	range->count = PCI_BUSDEVFN ( 0, ( max_bus + 1 ), 0, 0 );
 }
 
 /**
@@ -114,7 +118,7 @@ int pcibios_write ( struct pci_device *pci, uint32_t command, uint32_t value ){
 	return ( status >> 8 );
 }
 
-PROVIDE_PCIAPI ( pcbios, pci_num_bus, pcibios_num_bus );
+PROVIDE_PCIAPI ( pcbios, pci_discover, pcibios_discover );
 PROVIDE_PCIAPI_INLINE ( pcbios, pci_read_config_byte );
 PROVIDE_PCIAPI_INLINE ( pcbios, pci_read_config_word );
 PROVIDE_PCIAPI_INLINE ( pcbios, pci_read_config_dword );