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