Specifications

alt_dma_txchan_ioctl()
Prototype
int alt_dma_txchan_ioctl (alt_dma_txchan dma,
int req,
void* arg)
Commonly Called By
C/C++ programs
Device drivers
Thread-safe
See description.
Available from ISR
See description.
Include
<sys/alt_dma.h>
Description
The alt_dma_txchan_ioctl() function performs device specific I/O operations on the DMA transmit
channel, dma. For example, some 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.
For more information, refer to the "Generic Requests DMA Might Support" table (Table 14-1) for the
generic requests a device might support.
Whether a call to alt_dma_txchan_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_txchan_ioctl() function while DMA transfers are pending, or unpredictable
behavior could result.
Return
A negative return value indicates failure; otherwise the interpretation of the return value is request
specific.
Related Information
• alt_dma_rxchan_close() on page 14-13
• alt_dma_rxchan_depth() on page 14-12
• alt_dma_rxchan_open() on page 14-15
• alt_dma_rxchan_prepare() on page 14-16
• alt_dma_rxchan_reg() on page 14-17
• alt_dma_txchan_close() on page 14-18
• alt_dma_txchan_open() on page 14-20
NII5V2
2015.05.14
alt_dma_txchan_ioctl()
14-19
HAL API Reference
Altera Corporation
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