vme_dma_read - Reads data from the VMEbus using DMA.
Handle allocated by vme_init
Handle to a DMA buffer allocated by vme_dma_buffer_create.
Offset from the buffer base address. The first byte of data read is stored at this address.
VMEbus address.
Address modifier. Possible values are:
- VME_A16S - Short supervisory access.Number of bytes of data to transfer.
Flags used to indicate special transfer features. The value specified will be an "OR" of the following possible values for the Tundra Universe II device.
- VME_DMA_64_BIT - Enable 64-bit PCI bus transfersOne of the following data widths can be used. If a data width is not specified, a default value is chosen based on the address modifier:
- VME_DMA_DW_8One of the following settings of the VON counter can be used, to indicates how many bytes of data to transfer before the bus is released. If a flag is not specified, the bus is held until the transfer completes.
- VME_DMA_VON_256One of the following settings of the VOFF counter can be used, to indicates how many microseconds to wait before reaquiring the bus. If a flag is not specified, the bus is immediately re-requested.
- VME_DMA_VOFF_16Reads data from the VMEbus using DMA. The DMA engine is used to read data from the VMEbus into a specified DMA buffer.
0 on success, or -1 on failure.
Not all max data widths are available for all address modifiers.
The default max data width is the maximum available width for the given address modifier.