PCI

pci.c

#define PCI_IOPORT_CONFIG_ADDRESS            0x0cf8
#define PCI_IOPORT_CONFIG_DATA               0x0cfc
#define PCI_BUS_MAX                          255
#define PCI_DEVICE_MAX                       31
#define PCI_FUNC_MAX                         7
#define PCI_CONFIGREG_VENDOR_AND_DEVICE_ID   0x00
#define PCI_CONFIGREG_INTERRUPT              0x3c

typedef unsigned char  u8;
typedef unsigned short u16;
typedef unsigned long  u32;


typedef struct PCIDevice_st{

  u16   vendorID;
  u16   deviceID;
  u8    interruptLine;

} PCIDevice_st;




static void pci_findDevices (PCIDevice_st devices[], unsigned int devicesMax);
static u32 pci_readConfigRegister (u8 regAddr, u8 bus, u8 device, u8 func);


void pci_test (void){

 PCIDevice_st devices[100];

  pci_findDevices(devices, 100);

  for(int i=0; i < 255 && devices[i].vendorID != 0xffff; i++){

    if(devices[i].interruptLine == 0xff)
      print("PCI: device found (vendor: 0x%x) (device: 0x%x) (interrupt: none)\n", devices[i].vendorID, devices[i].deviceID);
    else
      print("PCI: device found (vendor: 0x%x) (device: 0x%x) (interrupt: %d)\n",  devices[i].vendorID, devices[i].deviceID, devices[i].interruptLine);
  }

  return;
}



static void pci_findDevices (PCIDevice_st devices[], unsigned int devicesMax){

 u32 reg;
 unsigned int i=0;


  for(unsigned int j=0; j <= PCI_BUS_MAX; j++){

    for(unsigned int k=0; k <= PCI_DEVICE_MAX; k++){

      for(unsigned int l=0; l <= PCI_FUNC_MAX; l++){

        // get Vendor ID and device ID
        reg = pci_readConfigRegister(PCI_CONFIGREG_VENDOR_AND_DEVICE_ID, j, k, l);

        // if vendor ID is 0xffff, the device (or function) is not exist
        if((reg>>16) == 0xffff){
          continue;
        }

        devices[i].vendorID = reg >> 16;
        devices[i].deviceID = reg & 0xffff;

        // get interrupt line
        reg = pci_readConfigRegister(PCI_CONFIGREG_INTERRUPT, j, k, l);

        // Notes: if the interrupt line is 0xff or the interrupt pin is 0, there is no connection
        devices[i].interruptLine = (((reg>>8) == 0x00)? 0xff : (reg & 0xff));

        i++;

        // in order to prevent stack overflow
        if(i+1 >= devicesMax){

          break;
        }
      }
    }
  }


  devices[i].vendorID      = 0xffff;
  devices[i].deviceID      = 0xffff;
  devices[i].interruptLine = 0xff;

  return;
}



static u32 pci_readConfigRegister (u8 regAddr, u8 bus, u8 device, u8 func){

 u32 ret;

  // tell PCI what I want to read
  asm_out32(PCI_IOPORT_CONFIG_ADDRESS,
                                       ((0       <<  0) & 0x00000000) | // bit 0-1:   must be 0
                                       ((regAddr <<  0) & 0x000000fc) | // bit 2-7:   register number
                                       ((func    <<  8) & 0x00000700) | // bit 8-10:  function number
                                       ((device  << 11) & 0x0000f800) | // bit 11-15: device   number
                                       ((bus     << 16) & 0x00ff0000) | // bit 16-23: bus      number
                                       ((0       << 24) & 0x7f000000) | // bit 24-30: reserved
                                       ((1       << 31) & 0x80000000)   // bit 31:    enable bit
           );

  // read CONFIG_DATA
  ret = asm_in32(PCI_IOPORT_CONFIG_DATA);

  // clear enable bit
  asm_out32(PCI_IOPORT_CONFIG_ADDRESS, 0x00000000);

  return ret;
}