Function ti_sdma_deactivate_channel

freebsd/arm/ti/ti_sdma.c:401–442

* ti_sdma_deactivate_channel - deactivates a channel * @ch: the channel to deactivate * * * * LOCKING: * DMA registers protected by internal mutex * * RETURNS: * EH_HANDLED or EH_NOT_HANDLED */

 *	EH_HANDLED or EH_NOT_HANDLED
 */
int
ti_sdma_deactivate_channel(unsigned int ch)
{
	struct ti_sdma_softc *sc = ti_sdma_sc;
	unsigned int j;
	unsigned int addr;

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

	TI_SDMA_LOCK(sc);

	/* First check if the channel is currently active */
	if ((sc->sc_active_channels & (1 << ch)) == 0) {
		TI_SDMA_UNLOCK(sc);
		return (EBUSY);
	}

	/* Mark the channel as inactive */
	sc->sc_active_channels &= ~(1 << ch);

	/* Disable all DMA interrupts for the channel. */
	ti_sdma_write_4(sc, DMA4_CICR(ch), 0);

	/* Make sure the DMA transfer is stopped. */
	ti_sdma_write_4(sc, DMA4_CCR(ch), 0);

	/* Clear the CSR register and IRQ status register */
	ti_sdma_write_4(sc, DMA4_CSR(ch), DMA4_CSR_CLEAR_MASK);
	for (j = 0; j < NUM_DMA_IRQS; j++) {
		ti_sdma_write_4(sc, DMA4_IRQSTATUS_L(j), (1 << ch));
	}

	/* Clear all the channel registers, this should abort any transaction */
	for (addr = DMA4_CCR(ch); addr <= DMA4_COLOR(ch); addr += 4)
		ti_sdma_write_4(sc, addr, 0x00000000);

	TI_SDMA_UNLOCK(sc);

	return 0;
}

/**
 *	ti_sdma_disable_channel_irq - disables IRQ's on the given channel