OPAL_PCI_MAP_PE_DMA_WINDOW_REAL

#define OPAL_PCI_MAP_PE_DMA_WINDOW_REAL              45

int64_t opal_pci_map_pe_dma_window_real(uint64_t phb_id,
                                        uint64_t pe_number,
                                        uint16_t window_id,
                                        uint64_t pci_start_addr,
                                        uint64_t pci_mem_size);

WARNING: following documentation is from old sources, and is possibly not representative of OPALv3 as implemented by skiboot. This should be used as a starting point for full documentation.

The host calls this function to initialize the specified DMA window for untranslated DMA addresses. This allows a PE to DMA directly to system memory without TCE translation. The DMA window PCI memory address is equal to the system memory real address. The PHB passes PCI address bits 04:63 directly to system real address bits 04:63 when PCI address bits 04:39 are within the region specified by mem_addr t0 mem_addr + window_size.

The addresses must be 16MB aligned and a multiple of 16MB in size.

phb_id
is the value from the PHB node ibm,opal-phbid property.
dma_window_number
specifies the DMA window

For ibm,opal-ioda PHBs the dma_window_number is an index from 0 to the PHB total number of windows minus 1. For ibm,opal-ioda2 PHBs the DMA window_number is an index from 0 to n-1, where n is the number of windows per window set, within the window set associated with the specified PE number.

pe_number
is the index of the PE that is authorized to DMA to this window address space in PCI memory,
mem_addr
is the starting 64-bit system real address mapped directly to the starting address in PCI memory. Addresses below 4GB are zero in bits above bit 32. This value must be aligned on a 16MB boundary; OPAL returns OPAL_PARAMETER for any value that is not a multiple of 16MB.
window_size
is the size, in bytes, of the address range defined by this window. This value must be a multiple of 16MB; OPAL returns OPAL_PARAMETER for any value that is not a multiple of 16MB. A value of ‘0’ indicates to disable this DMA window.