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/*
* This software is Copyright (C) 1998 by T.sqware - all rights limited
* It is provided in to the public domain "as is", can be freely modified
* as far as this copyight notice is kept unchanged, but does not imply
* an endorsement by T.sqware of the product in which it is included.
*/
#include <rtems.h>
#include <rtems/pci.h>
#include <rtems/bspIo.h>
static uint8_t pci_number_of_buses = 0xff;
unsigned char pci_bus_count(void)
{
if ( pci_number_of_buses != 0xff ) {
return pci_number_of_buses;
}
uint8_t bus;
uint8_t device;
uint8_t function;
uint8_t number_of_functions;
uint8_t header = 0;
uint8_t buses = 0;
uint32_t vendor = 0;
uint32_t class_rev = 0;
pci_number_of_buses = 0;
for (bus=0; bus < 0xff; bus++) {
for (device=0; device < PCI_MAX_DEVICES; device++) {
pci_read_config_dword(bus, device, 0, PCI_VENDOR_ID, &vendor);
if ( vendor == -1 ) {
continue;
}
pci_read_config_byte(bus, device, 0, PCI_HEADER_TYPE, &header);
number_of_functions = (header & 0x80) ? PCI_MAX_FUNCTIONS : 1;
for ( function=0; function < number_of_functions; function++ ) {
pci_read_config_dword(bus, device, function, PCI_VENDOR_ID, &vendor);
if ( vendor == -1 ) {
continue;
}
pci_read_config_dword(bus, device, function, PCI_CLASS_REVISION, &class_rev);
if ( (class_rev >> 16) == PCI_CLASS_BRIDGE_PCI ) {
pci_read_config_byte(bus, device, function, PCI_SUBORDINATE_BUS, &buses);
if ( buses > pci_number_of_buses ) {
pci_number_of_buses = buses;
}
}
}
}
}
if ( pci_number_of_buses == 0 ) {
printk("pci_bus_count() found 0 busses, assuming 1\n");
pci_number_of_buses = 1;
} else if ( pci_number_of_buses == 0xff ) {
printk("pci_bus_count() found 0xff busses, assuming 1\n");
pci_number_of_buses = 1;
}
return pci_number_of_buses;
}
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