Function ti_sdma_activate_channel

freebsd/arm/ti/ti_sdma.c:315–387

* ti_sdma_activate_channel - activates a DMA channel * @ch: upon return contains the channel allocated * @callback: a callback function to associate with the channel * @data: optional data supplied when the callback is called * * Simply activates a channel be enabling and writing default values to the * channel's register set. It doesn't start a transaction, just populates the * internal d

 *	0 on success, otherwise an error code
 */
int
ti_sdma_activate_channel(unsigned int *ch,
                          void (*callback)(unsigned int ch, uint32_t status, void *data),
                          void *data)
{
	struct ti_sdma_softc *sc = ti_sdma_sc;
	struct ti_sdma_channel *channel = NULL;
	uint32_t addr;
	unsigned int i;

	/* Sanity check */
	if (sc == NULL)
		return (ENOMEM);

	if (ch == NULL)
		return (EINVAL);

	TI_SDMA_LOCK(sc);

	/* Check to see if all channels are in use */
	if (sc->sc_active_channels == 0xffffffff) {
		TI_SDMA_UNLOCK(sc);
		return (ENOMEM);
	}

	/* Find the first non-active channel */
	for (i = 0; i < NUM_DMA_CHANNELS; i++) {
		if (!(sc->sc_active_channels & (0x1 << i))) {
			sc->sc_active_channels |= (0x1 << i);
			*ch = i;
			break;
		}
	}

	/* Get the channel struct and populate the fields */
	channel = &sc->sc_channel[*ch];

	channel->callback = callback;
	channel->callback_data = data;

	channel->need_reg_write = 1;

	/* Set the default configuration for the DMA channel */
	channel->reg_csdp = DMA4_CSDP_DATA_TYPE(0x2)
		| DMA4_CSDP_SRC_BURST_MODE(0)
		| DMA4_CSDP_DST_BURST_MODE(0)
		| DMA4_CSDP_SRC_ENDIANISM(0)
		| DMA4_CSDP_DST_ENDIANISM(0)
		| DMA4_CSDP_WRITE_MODE(0)
		| DMA4_CSDP_SRC_PACKED(0)
		| DMA4_CSDP_DST_PACKED(0);

	channel->reg_ccr = DMA4_CCR_DST_ADDRESS_MODE(1)
		| DMA4_CCR_SRC_ADDRESS_MODE(1)
		| DMA4_CCR_READ_PRIORITY(0)
		| DMA4_CCR_WRITE_PRIORITY(0)
		| DMA4_CCR_SYNC_TRIGGER(0)
		| DMA4_CCR_FRAME_SYNC(0)