Visible to Intel only — GUID: ipf1652925447641
Ixiasoft
Visible to Intel only — GUID: ipf1652925447641
Ixiasoft
16.1.1.24. alt_dma_rxchan_ioctl()
Prototype
int alt_dma_rxchan_ioctl (alt_dma_rxchan dma,
int req,
void* arg)
Commonly Called By
C/C++ programsDevice drivers
Thread-safe
See description.Available from ISR
See description.Include
<sys/alt_dma.h>Description
The alt_dma_rxchan_ioctl() function performs DMA I/O operations on the DMA receive channel, dma. The I/O operations are device specific. For example, some DMA drivers support options to control the width of the transfer operations. The input argument, req, is an enumeration of the requested operation; arg is an additional argument for the request. The interpretation of arg is request dependent.Whether a call to alt_dma_rxchan_ioctl() is thread-safe, or can be called from an ISR, is device dependent. In general it safest to assume that it is not thread-safe.
Do not call the alt_dma_rxchan_ioctl() function while DMA transfers are pending or can result in unpredictable behavior.
For device-specific information about the Intel FPGA® DMA controller core, refer to the "DMA Controller Core" chapter in the Embedded Peripherals IP User Guide.
Return
A negative return value indicates failure. The interpretation of nonnegative return values is request specific.Request | Meaning |
---|---|
ALT_DMA_SET_MODE_8 | Transfer data in units of 8 bits. The value of arg is ignored. |
ALT_DMA_SET_MODE_16 | Transfer data in units of 16 bits. The value of arg is ignored. |
ALT_DMA_SET_MODE_32 | Transfer data in units of 32 bits. The value of arg is ignored. |
ALT_DMA_SET_MODE_64 | Transfer data in units of 64 bits. The value of arg is ignored. |
ALT_DMA_SET_MODE_128 | Transfer data in units of 128 bits. The value of arg is ignored. |
ALT_DMA_GET_MODE | Return the transfer width. The value of arg is ignored. |
ALT_DMA_TX_ONLY_ON | The ALT_DMA_TX_ONLY_ON request causes a DMA channel to operate in a mode in which only the transmitter is under software control. The other side writes continuously from a single location. The address to which to write is the argument to this request. |
ALT_DMA_TX_ONLY_OFF | Return to the default mode, in which both the receive and transmit sides of the DMA can be under software control. |
ALT_DMA_RX_ONLY_ON | The ALT_DMA_RX_ONLY_ON request causes a DMA channel to operate in a mode in which only the receiver is under software control. The other side reads continuously from a single location. The address to read is the argument to this request. |
ALT_DMA_RX_ONLY_OFF | Return to the default mode, in which both the receive and transmit sides of the DMA can be under software control. |