Code

A sample buffer to send, number of entries to send and address of slave:

#define DATA_LENGTH 10
static uint8_t buffer[DATA_LENGTH] = {
        0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09,
};

#define SLAVE_ADDRESS 0x12

Number of times to try to send packet if it fails:

#define TIMEOUT 1000

Globally accessible module structure:

struct i2c_master_module i2c_master_instance;

Function for setting up the module:

static void configure_i2c_master(void)
{
    /* Initialize config structure and software module. */
    struct i2c_master_config config_i2c_master;
    i2c_master_get_config_defaults(&config_i2c_master);

    /* Change buffer timeout to something longer. */
    config_i2c_master.buffer_timeout = 10000;

    /* Initialize and enable device with config. */
    i2c_master_init(&i2c_master_instance, CONF_I2C_MASTER_MODULE, &config_i2c_master);

    i2c_master_enable(&i2c_master_instance);
}

Globally accessible DMA module structure:

struct dma_resource example_resource;

Globally transfer done flag:

static volatile bool transfer_is_done = false;

Globally accessible DMA transfer descriptor:

COMPILER_ALIGNED(16)
DmacDescriptor example_descriptor;

Function for transfer done callback:

static void transfer_done(struct dma_resource* const resource )
{
    UNUSED(resource);

    transfer_is_done = true;
}

Function for setting up the DMA resource:

static void configure_dma_resource(struct dma_resource *resource)
{
    struct dma_resource_config config;

    dma_get_config_defaults(&config);

    config.peripheral_trigger = CONF_I2C_DMA_TRIGGER;
    config.trigger_action = DMA_TRIGGER_ACTON_BEAT;

    dma_allocate(resource, &config);
}

Function for setting up the DMA transfer descriptor:

static void setup_dma_descriptor(DmacDescriptor *descriptor)
{
    struct dma_descriptor_config descriptor_config;

    dma_descriptor_get_config_defaults(&descriptor_config);

    descriptor_config.beat_size = DMA_BEAT_SIZE_BYTE;
    descriptor_config.dst_increment_enable = false;
    descriptor_config.block_transfer_count = DATA_LENGTH;
    descriptor_config.source_address = (uint32_t)buffer + DATA_LENGTH;
    descriptor_config.destination_address =
            (uint32_t)(&i2c_master_instance.hw->I2CM.DATA.reg);

    dma_descriptor_create(descriptor, &descriptor_config);
}

Add to user application main():

configure_i2c_master();

configure_dma_resource(&example_resource);
setup_dma_descriptor(&example_descriptor);
dma_add_descriptor(&example_resource, &example_descriptor);
dma_register_callback(&example_resource, transfer_done,
        DMA_CALLBACK_TRANSFER_DONE);
dma_enable_callback(&example_resource, DMA_CALLBACK_TRANSFER_DONE);