87 lines
2.3 KiB
C
87 lines
2.3 KiB
C
FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
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#include <stdint.h>
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#include <ipxe/pci.h>
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/**
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* Look for a PCI capability
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*
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* @v pci PCI device to query
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* @v cap Capability code
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* @ret address Address of capability, or 0 if not found
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*
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* Determine whether or not a device supports a given PCI capability.
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* Returns the address of the requested capability structure within
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* the device's PCI configuration space, or 0 if the device does not
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* support it.
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*/
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int pci_find_capability ( struct pci_device *pci, int cap ) {
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uint16_t status;
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uint8_t pos, id;
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uint8_t hdr_type;
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int ttl = 48;
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pci_read_config_word ( pci, PCI_STATUS, &status );
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if ( ! ( status & PCI_STATUS_CAP_LIST ) )
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return 0;
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pci_read_config_byte ( pci, PCI_HEADER_TYPE, &hdr_type );
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switch ( hdr_type & 0x7F ) {
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case PCI_HEADER_TYPE_NORMAL:
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case PCI_HEADER_TYPE_BRIDGE:
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default:
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pci_read_config_byte ( pci, PCI_CAPABILITY_LIST, &pos );
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break;
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case PCI_HEADER_TYPE_CARDBUS:
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pci_read_config_byte ( pci, PCI_CB_CAPABILITY_LIST, &pos );
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break;
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}
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while ( ttl-- && pos >= 0x40 ) {
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pos &= ~3;
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pci_read_config_byte ( pci, pos + PCI_CAP_LIST_ID, &id );
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DBG ( "PCI Capability: %d\n", id );
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if ( id == 0xff )
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break;
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if ( id == cap )
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return pos;
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pci_read_config_byte ( pci, pos + PCI_CAP_LIST_NEXT, &pos );
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}
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return 0;
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}
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/**
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* Find the size of a PCI BAR
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*
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* @v pci PCI device
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* @v reg PCI register number
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* @ret size BAR size
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*
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* It should not be necessary for any Etherboot code to call this
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* function.
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*/
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unsigned long pci_bar_size ( struct pci_device *pci, unsigned int reg ) {
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uint16_t cmd;
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uint32_t start, size;
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/* Save the original command register */
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pci_read_config_word ( pci, PCI_COMMAND, &cmd );
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/* Save the original bar */
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pci_read_config_dword ( pci, reg, &start );
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/* Compute which bits can be set */
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pci_write_config_dword ( pci, reg, ~0 );
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pci_read_config_dword ( pci, reg, &size );
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/* Restore the original size */
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pci_write_config_dword ( pci, reg, start );
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/* Find the significant bits */
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/* Restore the original command register. This reenables decoding. */
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pci_write_config_word ( pci, PCI_COMMAND, cmd );
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if ( start & PCI_BASE_ADDRESS_SPACE_IO ) {
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size &= PCI_BASE_ADDRESS_IO_MASK;
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} else {
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size &= PCI_BASE_ADDRESS_MEM_MASK;
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}
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/* Find the lowest bit set */
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size = size & ~( size - 1 );
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return size;
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}
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