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Commit f6160f35 authored by Dmitry Osipenko's avatar Dmitry Osipenko Committed by Vinod Koul
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dmaengine: tegra-apb: Support non-flow controlled slave configuration 



This allows DMA client to issue a non-flow controlled TX. In particular
it is needed for the fuse driver that reads fuse registers using APBDMA
to workaround a HW bug that results in hang when CPU and DMA perform
simultaneous access to fuse peripheral.

Signed-off-by: default avatarDmitry Osipenko <digetx@gmail.com>
Reviewed-by: default avatarJon Hunter <jonathanh@nvidia.com>
Signed-off-by: default avatarVinod Koul <vinod.koul@intel.com>
parent 4fbd8d19

drivers/dma/tegra20-apb-dma.c

+14 −5
Original line number Diff line number Diff line
@@ -353,7 +353,8 @@ static int tegra_dma_slave_config(struct dma_chan *dc, 
	}



	memcpy(&tdc->dma_sconfig, sconfig, sizeof(*sconfig));

	if (tdc->slave_id == TEGRA_APBDMA_SLAVE_ID_INVALID) {

	if (tdc->slave_id == TEGRA_APBDMA_SLAVE_ID_INVALID &&

	    sconfig->device_fc) {

		if (sconfig->slave_id > TEGRA_APBDMA_CSR_REQ_SEL_MASK)

			return -EINVAL;

		tdc->slave_id = sconfig->slave_id;
@@ -970,8 +971,13 @@ static struct dma_async_tx_descriptor *tegra_dma_prep_slave_sg( 
					TEGRA_APBDMA_AHBSEQ_WRAP_SHIFT;

	ahb_seq |= TEGRA_APBDMA_AHBSEQ_BUS_WIDTH_32;



	csr |= TEGRA_APBDMA_CSR_ONCE | TEGRA_APBDMA_CSR_FLOW;

	csr |= TEGRA_APBDMA_CSR_ONCE;



	if (tdc->slave_id != TEGRA_APBDMA_SLAVE_ID_INVALID) {

		csr |= TEGRA_APBDMA_CSR_FLOW;

		csr |= tdc->slave_id << TEGRA_APBDMA_CSR_REQ_SEL_SHIFT;

	}



	if (flags & DMA_PREP_INTERRUPT)

		csr |= TEGRA_APBDMA_CSR_IE_EOC;
@@ -1110,10 +1116,13 @@ static struct dma_async_tx_descriptor *tegra_dma_prep_dma_cyclic( 
					TEGRA_APBDMA_AHBSEQ_WRAP_SHIFT;

	ahb_seq |= TEGRA_APBDMA_AHBSEQ_BUS_WIDTH_32;



	if (tdc->slave_id != TEGRA_APBDMA_SLAVE_ID_INVALID) {

		csr |= TEGRA_APBDMA_CSR_FLOW;

		csr |= tdc->slave_id << TEGRA_APBDMA_CSR_REQ_SEL_SHIFT;

	}



	if (flags & DMA_PREP_INTERRUPT)

		csr |= TEGRA_APBDMA_CSR_IE_EOC;

	csr |= tdc->slave_id << TEGRA_APBDMA_CSR_REQ_SEL_SHIFT;



	apb_seq |= TEGRA_APBDMA_APBSEQ_WRAP_WORD_1;