Struct imxrt_hal::dma::Dma

pub struct Dma<const CHANNELS: usize> { /* private fields */ }

A DMA driver.

This DMA driver manages the DMA controller and the multiplexer. It’s configured with pointers to both peripherals.

Dma allocates Channels. Channel provides the interface for scheduling transfers.

Implementations

impl<const CHANNELS: usize> Dma<CHANNELS>

pub unsafe fn channel(&'static self, index: usize) -> Channel

Creates the DMA channel described by index.

Safety

This will create a handle that may alias global, mutable state. You should only create one channel per index. If there are multiple channels for the same index, you’re responsible for ensuring synchronized access.

Panics

Panics if index is greater than or equal to the maximum number of channels.

impl<const CHANNELS: usize> Dma<CHANNELS>

pub unsafe fn on_interrupt(&'static self, channel: usize)

Handle a DMA interrupt

Checks the interrupt status for the channel identified by channel. If the channel completed its transfer, on_interrupt wakes the channel’s waker.

Consider calling on_interrupt in a DMA channel’s interrupt handler:

use imxrt_dma::Dma;
static DMA: Dma<32> = // Handle to DMA driver.

// #[cortex_m_rt::interrupt]
fn DMA7_DMA23() {
    // Safety: only checking channels 7 and 23, which
    // are both valid on an i.MX RT 1060 chip.
    unsafe {
        DMA.on_interrupt(7);
        DMA.on_interrupt(23);
    }
}

Safety

This should only be used when the associated DMA channel is exclusively referenced by a DMA transfer future. Caller must ensure that on_interrupt is called in the correct interrupt handler.

Panics

Panics if channel is greater than or equal to the maximum number of channels.

impl<const CHANNELS: usize> Dma<CHANNELS>

pub const unsafe fn new( controller: *const (), multiplexer: *const () ) -> Dma<CHANNELS>

Create the DMA driver.

Note that this can evaluate at compile time. Consider using this to expose a Dma through your higher-level API that you can use to allocate DMA channels.

CHANNELS specifies the total number of channels supported by the DMA controller. It’s referenced when allocating channels.

Safety

Caller must make sure that controller is a pointer to the start of the DMA controller register block. Caller must also make sure that multiplexer is a pointer to the start of the DMA multiplexer. Both pointers must be valid for your MCU.

An incorrect CHANNELS value prevents proper bounds checking when allocating channels. This may result in DMA channels that point to invalid memory.

Trait Implementations

impl<const CHANNELS: usize> Sync for Dma<CHANNELS>