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Commit 601cd6e2 authored by Zhenfang Wang's avatar Zhenfang Wang Committed by Greg Kroah-Hartman
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UPSTREAM: dmaengine: sprd: Set request pending flag when DMA controller is active 



On new Spreadtrum platforms, when the CPU enters idle, it will close
the DMA controllers' clock to save power if the DMA controller is not
busy. Moreover the DMA controller's busy signal depends on the DMA
enable flag and the request pending flag.

When DMA controller starts to transfer data, which means we already
set the DMA enable flag, but now we should also set the request pending
flag, in case the DMA clock will be closed accidentally if the CPU
can not detect the DMA controller's busy signal.

bug: 153500755
Change-Id: I9123685be01312db4caa47a742e6e6d0c8ef4e08
Signed-off-by: default avatarZhenfang Wang <zhenfang.wang@unisoc.com>
Signed-off-by: default avatarBaolin Wang <baolin.wang7@gmail.com>
Link: https://lore.kernel.org/r/02adbe4364ec436ec2c5bc8fd2386bab98edd884.1584019223.git.baolin.wang7@gmail.com


Signed-off-by: default avatarVinod Koul <vkoul@kernel.org>
(cherry picked from commit d0f19a48a185dab592afe1e18bf31a9d6790620d)
parent 33717ea7

drivers/dma/sprd-dma.c

+24 −0
Original line number Diff line number Diff line
@@ -486,6 +486,28 @@ static int sprd_dma_set_2stage_config(struct sprd_dma_chn *schan) 
	return 0;

}



static void sprd_dma_set_pending(struct sprd_dma_chn *schan, bool enable)

{

	struct sprd_dma_dev *sdev = to_sprd_dma_dev(&schan->vc.chan);

	u32 reg, val, req_id;



	if (schan->dev_id == SPRD_DMA_SOFTWARE_UID)

		return;



	/* The DMA request id always starts from 0. */

	req_id = schan->dev_id - 1;



	if (req_id < 32) {

		reg = SPRD_DMA_GLB_REQ_PEND0_EN;

		val = BIT(req_id);

	} else {

		reg = SPRD_DMA_GLB_REQ_PEND1_EN;

		val = BIT(req_id - 32);

	}



	sprd_dma_glb_update(sdev, reg, val, enable ? val : 0);

}



static void sprd_dma_set_chn_config(struct sprd_dma_chn *schan,

				    struct sprd_dma_desc *sdesc)

{
@@ -532,6 +554,7 @@ static void sprd_dma_start(struct sprd_dma_chn *schan) 
	 */

	sprd_dma_set_chn_config(schan, schan->cur_desc);

	sprd_dma_set_uid(schan);

	sprd_dma_set_pending(schan, true);

	sprd_dma_enable_chn(schan);



	if (schan->dev_id == SPRD_DMA_SOFTWARE_UID &&
@@ -543,6 +566,7 @@ static void sprd_dma_start(struct sprd_dma_chn *schan) 
static void sprd_dma_stop(struct sprd_dma_chn *schan)

{

	sprd_dma_stop_and_disable(schan);

	sprd_dma_set_pending(schan, false);

	sprd_dma_unset_uid(schan);

	sprd_dma_clear_int(schan);

	schan->cur_desc = NULL;