Commit d8fa0802 authored by Serge Semin's avatar Serge Semin Committed by Vinod Koul
Browse files

dmaengine: dw: Simplify max-burst calculation procedure 



In order to have a more coherent DW AHB DMA slave configuration method -
dwc_config() - let's simplify the source and destination channel max-burst
calculation procedure:

1. Create the max-burst verification method as it has been just done for
the memory and peripheral address widths. Thus the dwc_config() method
will turn to a set of the verification methods execution.

2. Since both the generic DW AHB DMA and Intel iDMA 32-bit engines support
the power-of-2 bursts only, then the specified by the client driver
max-burst values can be converted to being power-of-2 right in the
max-burst verification method.

3. Since max-burst encoded value is required on the CTL_LO fields
calculation stage, the encode_maxburst() callback can be easily dropped
from the dw_dma structure meanwhile the encoding procedure will be
executed right in the CTL_LO register value calculation.

Thus the update will provide the next positive effects: the internal
DMA-slave config structure will contain only the real DMA-transfer config
values, which will be encoded to the DMA-controller register fields only
when it's required on the buffer mapping; the redundant encode_maxburst()
callback will be dropped simplifying the internal HW-abstraction API;
dwc_config() will look more readable executing the verification functions
one-by-one.

Signed-off-by: default avatarSerge Semin <fancer.lancer@gmail.com>
Acked-by: default avatarAndy Shevchenko <andy@kernel.org>
Link: https://lore.kernel.org/r/20240802075100.6475-6-fancer.lancer@gmail.com


Signed-off-by: default avatarVinod Koul <vkoul@kernel.org>
parent 3acb301d

drivers/dma/dw/core.c

+21 −9
Original line number Diff line number Diff line
@@ -779,6 +779,23 @@ bool dw_dma_filter(struct dma_chan *chan, void *param) 
}

EXPORT_SYMBOL_GPL(dw_dma_filter);



static int dwc_verify_maxburst(struct dma_chan *chan)

{

	struct dw_dma_chan *dwc = to_dw_dma_chan(chan);



	dwc->dma_sconfig.src_maxburst =

		clamp(dwc->dma_sconfig.src_maxburst, 1U, dwc->max_burst);

	dwc->dma_sconfig.dst_maxburst =

		clamp(dwc->dma_sconfig.dst_maxburst, 1U, dwc->max_burst);



	dwc->dma_sconfig.src_maxburst =

		rounddown_pow_of_two(dwc->dma_sconfig.src_maxburst);

	dwc->dma_sconfig.dst_maxburst =

		rounddown_pow_of_two(dwc->dma_sconfig.dst_maxburst);



	return 0;

}



static int dwc_verify_p_buswidth(struct dma_chan *chan)

{

	struct dw_dma_chan *dwc = to_dw_dma_chan(chan);
@@ -838,7 +855,7 @@ static int dwc_verify_m_buswidth(struct dma_chan *chan) 
		dwc->dma_sconfig.src_addr_width = mem_width;

	} else if (dwc->dma_sconfig.direction == DMA_DEV_TO_MEM) {

		reg_width = dwc->dma_sconfig.src_addr_width;

		reg_burst = rounddown_pow_of_two(dwc->dma_sconfig.src_maxburst);

		reg_burst = dwc->dma_sconfig.src_maxburst;



		dwc->dma_sconfig.dst_addr_width = min(mem_width, reg_width * reg_burst);

	}
@@ -849,15 +866,13 @@ static int dwc_verify_m_buswidth(struct dma_chan *chan) 
static int dwc_config(struct dma_chan *chan, struct dma_slave_config *sconfig)

{

	struct dw_dma_chan *dwc = to_dw_dma_chan(chan);

	struct dw_dma *dw = to_dw_dma(chan->device);

	int ret;



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



	dwc->dma_sconfig.src_maxburst =

		clamp(dwc->dma_sconfig.src_maxburst, 1U, dwc->max_burst);

	dwc->dma_sconfig.dst_maxburst =

		clamp(dwc->dma_sconfig.dst_maxburst, 1U, dwc->max_burst);

	ret = dwc_verify_maxburst(chan);

	if (ret)

		return ret;



	ret = dwc_verify_p_buswidth(chan);

	if (ret)
@@ -867,9 +882,6 @@ static int dwc_config(struct dma_chan *chan, struct dma_slave_config *sconfig) 
	if (ret)

		return ret;



	dw->encode_maxburst(dwc, &dwc->dma_sconfig.src_maxburst);

	dw->encode_maxburst(dwc, &dwc->dma_sconfig.dst_maxburst);



	return 0;

}

drivers/dma/dw/dw.c

+4 −5
Original line number Diff line number Diff line
@@ -64,13 +64,13 @@ static size_t dw_dma_block2bytes(struct dw_dma_chan *dwc, u32 block, u32 width) 
	return DWC_CTLH_BLOCK_TS(block) << width;

}



static void dw_dma_encode_maxburst(struct dw_dma_chan *dwc, u32 *maxburst)

static inline u8 dw_dma_encode_maxburst(u32 maxburst)

{

	/*

	 * Fix burst size according to dw_dmac. We need to convert them as:

	 * 1 -> 0, 4 -> 1, 8 -> 2, 16 -> 3.

	 */

	*maxburst = *maxburst > 1 ? fls(*maxburst) - 2 : 0;

	return maxburst > 1 ? fls(maxburst) - 2 : 0;

}



static u32 dw_dma_prepare_ctllo(struct dw_dma_chan *dwc)
@@ -82,11 +82,11 @@ static u32 dw_dma_prepare_ctllo(struct dw_dma_chan *dwc) 
	if (dwc->direction == DMA_MEM_TO_DEV) {

		sms = dwc->dws.m_master;

		dms = dwc->dws.p_master;

		dmsize = sconfig->dst_maxburst;

		dmsize = dw_dma_encode_maxburst(sconfig->dst_maxburst);

	} else if (dwc->direction == DMA_DEV_TO_MEM) {

		sms = dwc->dws.p_master;

		dms = dwc->dws.m_master;

		smsize = sconfig->src_maxburst;

		smsize = dw_dma_encode_maxburst(sconfig->src_maxburst);

	} else /* DMA_MEM_TO_MEM */ {

		sms = dwc->dws.m_master;

		dms = dwc->dws.m_master;
@@ -125,7 +125,6 @@ int dw_dma_probe(struct dw_dma_chip *chip) 
	dw->suspend_chan = dw_dma_suspend_chan;

	dw->resume_chan = dw_dma_resume_chan;

	dw->prepare_ctllo = dw_dma_prepare_ctllo;

	dw->encode_maxburst = dw_dma_encode_maxburst;

	dw->bytes2block = dw_dma_bytes2block;

	dw->block2bytes = dw_dma_block2bytes;

drivers/dma/dw/idma32.c

+4 −5
Original line number Diff line number Diff line
@@ -199,9 +199,9 @@ static size_t idma32_block2bytes(struct dw_dma_chan *dwc, u32 block, u32 width) 
	return IDMA32C_CTLH_BLOCK_TS(block);

}



static void idma32_encode_maxburst(struct dw_dma_chan *dwc, u32 *maxburst)

static inline u8 idma32_encode_maxburst(u32 maxburst)

{

	*maxburst = *maxburst > 1 ? fls(*maxburst) - 1 : 0;

	return maxburst > 1 ? fls(maxburst) - 1 : 0;

}



static u32 idma32_prepare_ctllo(struct dw_dma_chan *dwc)
@@ -210,9 +210,9 @@ static u32 idma32_prepare_ctllo(struct dw_dma_chan *dwc) 
	u8 smsize = 0, dmsize = 0;



	if (dwc->direction == DMA_MEM_TO_DEV)

		dmsize = sconfig->dst_maxburst;

		dmsize = idma32_encode_maxburst(sconfig->dst_maxburst);

	else if (dwc->direction == DMA_DEV_TO_MEM)

		smsize = sconfig->src_maxburst;

		smsize = idma32_encode_maxburst(sconfig->src_maxburst);



	return DWC_CTLL_LLP_D_EN | DWC_CTLL_LLP_S_EN |

	       DWC_CTLL_DST_MSIZE(dmsize) | DWC_CTLL_SRC_MSIZE(smsize);
@@ -274,7 +274,6 @@ int idma32_dma_probe(struct dw_dma_chip *chip) 
	dw->suspend_chan = idma32_suspend_chan;

	dw->resume_chan = idma32_resume_chan;

	dw->prepare_ctllo = idma32_prepare_ctllo;

	dw->encode_maxburst = idma32_encode_maxburst;

	dw->bytes2block = idma32_bytes2block;

	dw->block2bytes = idma32_block2bytes;

drivers/dma/dw/regs.h

+0 −1
Original line number Diff line number Diff line
@@ -327,7 +327,6 @@ struct dw_dma { 
	void	(*suspend_chan)(struct dw_dma_chan *dwc, bool drain);

	void	(*resume_chan)(struct dw_dma_chan *dwc, bool drain);

	u32	(*prepare_ctllo)(struct dw_dma_chan *dwc);

	void	(*encode_maxburst)(struct dw_dma_chan *dwc, u32 *maxburst);

	u32	(*bytes2block)(struct dw_dma_chan *dwc, size_t bytes,

			       unsigned int width, size_t *len);

	size_t	(*block2bytes)(struct dw_dma_chan *dwc, u32 block, u32 width);