1 | /* |
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2 | * This software is Copyright (C) 1998 by T.sqware - all rights limited |
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3 | * It is provided in to the public domain "as is", can be freely modified |
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4 | * as far as this copyight notice is kept unchanged, but does not imply |
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5 | * an endorsement by T.sqware of the product in which it is included. |
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6 | */ |
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7 | |
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8 | #include <rtems.h> |
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9 | #include <rtems/pci.h> |
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10 | #include <rtems/bspIo.h> |
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11 | |
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12 | static uint8_t pci_number_of_buses = 0xff; |
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13 | |
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14 | unsigned char pci_bus_count(void) |
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15 | { |
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16 | if ( pci_number_of_buses != 0xff ) { |
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17 | return pci_number_of_buses; |
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18 | } |
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19 | |
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20 | uint8_t bus; |
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21 | uint8_t device; |
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22 | uint8_t function; |
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23 | uint8_t number_of_functions; |
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24 | uint8_t header = 0; |
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25 | uint8_t buses = 0; |
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26 | uint32_t vendor = 0; |
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27 | uint32_t class_rev = 0; |
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28 | |
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29 | pci_number_of_buses = 0; |
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30 | |
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31 | for (bus=0; bus < 0xff; bus++) { |
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32 | for (device=0; device < PCI_MAX_DEVICES; device++) { |
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33 | |
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34 | pci_read_config_dword(bus, device, 0, PCI_VENDOR_ID, &vendor); |
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35 | if ( vendor == -1 ) { |
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36 | continue; |
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37 | } |
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38 | |
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39 | pci_read_config_byte(bus, device, 0, PCI_HEADER_TYPE, &header); |
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40 | number_of_functions = (header & 0x80) ? PCI_MAX_FUNCTIONS : 1; |
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41 | |
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42 | for ( function=0; function < number_of_functions; function++ ) { |
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43 | pci_read_config_dword(bus, device, function, PCI_VENDOR_ID, &vendor); |
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44 | if ( vendor == -1 ) { |
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45 | continue; |
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46 | } |
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47 | |
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48 | pci_read_config_dword(bus, device, function, PCI_CLASS_REVISION, &class_rev); |
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49 | if ( (class_rev >> 16) == PCI_CLASS_BRIDGE_PCI ) { |
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50 | pci_read_config_byte(bus, device, function, PCI_SUBORDINATE_BUS, &buses); |
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51 | if ( buses > pci_number_of_buses ) { |
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52 | pci_number_of_buses = buses; |
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53 | } |
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54 | } |
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55 | } |
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56 | } |
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57 | } |
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58 | |
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59 | if ( pci_number_of_buses == 0 ) { |
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60 | printk("pci_bus_count() found 0 busses, assuming 1\n"); |
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61 | pci_number_of_buses = 1; |
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62 | } else if ( pci_number_of_buses == 0xff ) { |
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63 | printk("pci_bus_count() found 0xff busses, assuming 1\n"); |
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64 | pci_number_of_buses = 1; |
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65 | } |
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66 | |
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67 | return pci_number_of_buses; |
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68 | } |
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