Commit 76a09663 authored by Paul Cercueil's avatar Paul Cercueil Committed by Vinod Koul
Browse files

dmaengine: jz4780: Support bidirectional I/O on one channel 



For some devices with only half-duplex capabilities, it doesn't make
much sense to use one DMA channel per direction, as both channels will
never be active at the same time.

Add support for bidirectional I/O on DMA channels. The client drivers
can then request a "tx-rx" DMA channel which will be used for both
directions.

Signed-off-by: default avatarPaul Cercueil <paul@crapouillou.net>
Link: https://lore.kernel.org/r/20211206174259.68133-7-paul@crapouillou.net


Signed-off-by: default avatarVinod Koul <vkoul@kernel.org>
parent c8c0cda8

drivers/dma/dma-jz4780.c

+32 −16
Original line number Diff line number Diff line
@@ -122,6 +122,7 @@ struct jz4780_dma_desc { 
	dma_addr_t desc_phys;

	unsigned int count;

	enum dma_transaction_type type;

	u32 transfer_type;

	u32 status;

};
@@ -130,7 +131,7 @@ struct jz4780_dma_chan { 
	unsigned int id;

	struct dma_pool *desc_pool;



	u32 transfer_type;

	u32 transfer_type_tx, transfer_type_rx;

	u32 transfer_shift;

	struct dma_slave_config	config;
@@ -157,7 +158,7 @@ struct jz4780_dma_dev { 
};



struct jz4780_dma_filter_data {

	u32 transfer_type;

	u32 transfer_type_tx, transfer_type_rx;

	int channel;

};
@@ -226,9 +227,10 @@ static inline void jz4780_dma_chan_disable(struct jz4780_dma_dev *jzdma, 
		jz4780_dma_ctrl_writel(jzdma, JZ_DMA_REG_DCKEC, BIT(chn));

}



static struct jz4780_dma_desc *jz4780_dma_desc_alloc(

	struct jz4780_dma_chan *jzchan, unsigned int count,

	enum dma_transaction_type type)

static struct jz4780_dma_desc *

jz4780_dma_desc_alloc(struct jz4780_dma_chan *jzchan, unsigned int count,

		      enum dma_transaction_type type,

		      enum dma_transfer_direction direction)

{

	struct jz4780_dma_desc *desc;
@@ -248,6 +250,12 @@ static struct jz4780_dma_desc *jz4780_dma_desc_alloc( 


	desc->count = count;

	desc->type = type;



	if (direction == DMA_DEV_TO_MEM)

		desc->transfer_type = jzchan->transfer_type_rx;

	else

		desc->transfer_type = jzchan->transfer_type_tx;



	return desc;

}
@@ -361,7 +369,7 @@ static struct dma_async_tx_descriptor *jz4780_dma_prep_slave_sg( 
	unsigned int i;

	int err;



	desc = jz4780_dma_desc_alloc(jzchan, sg_len, DMA_SLAVE);

	desc = jz4780_dma_desc_alloc(jzchan, sg_len, DMA_SLAVE, direction);

	if (!desc)

		return NULL;
@@ -410,7 +418,7 @@ static struct dma_async_tx_descriptor *jz4780_dma_prep_dma_cyclic( 


	periods = buf_len / period_len;



	desc = jz4780_dma_desc_alloc(jzchan, periods, DMA_CYCLIC);

	desc = jz4780_dma_desc_alloc(jzchan, periods, DMA_CYCLIC, direction);

	if (!desc)

		return NULL;
@@ -455,14 +463,14 @@ static struct dma_async_tx_descriptor *jz4780_dma_prep_dma_memcpy( 
	struct jz4780_dma_desc *desc;

	u32 tsz;



	desc = jz4780_dma_desc_alloc(jzchan, 1, DMA_MEMCPY);

	desc = jz4780_dma_desc_alloc(jzchan, 1, DMA_MEMCPY, 0);

	if (!desc)

		return NULL;



	tsz = jz4780_dma_transfer_size(jzchan, dest | src | len,

				       &jzchan->transfer_shift);



	jzchan->transfer_type = JZ_DMA_DRT_AUTO;

	desc->transfer_type = JZ_DMA_DRT_AUTO;



	desc->desc[0].dsa = src;

	desc->desc[0].dta = dest;
@@ -528,7 +536,7 @@ static void jz4780_dma_begin(struct jz4780_dma_chan *jzchan) 


	/* Set transfer type. */

	jz4780_dma_chn_writel(jzdma, jzchan->id, JZ_DMA_REG_DRT,

			      jzchan->transfer_type);

			      jzchan->desc->transfer_type);



	/*

	 * Set the transfer count. This is redundant for a descriptor-driven
@@ -788,7 +796,8 @@ static bool jz4780_dma_filter_fn(struct dma_chan *chan, void *param) 
		return false;

	}



	jzchan->transfer_type = data->transfer_type;

	jzchan->transfer_type_tx = data->transfer_type_tx;

	jzchan->transfer_type_rx = data->transfer_type_rx;



	return true;

}
@@ -800,11 +809,17 @@ static struct dma_chan *jz4780_of_dma_xlate(struct of_phandle_args *dma_spec, 
	dma_cap_mask_t mask = jzdma->dma_device.cap_mask;

	struct jz4780_dma_filter_data data;



	if (dma_spec->args_count != 2)

		return NULL;



	data.transfer_type = dma_spec->args[0];

	if (dma_spec->args_count == 2) {

		data.transfer_type_tx = dma_spec->args[0];

		data.transfer_type_rx = dma_spec->args[0];

		data.channel = dma_spec->args[1];

	} else if (dma_spec->args_count == 3) {

		data.transfer_type_tx = dma_spec->args[0];

		data.transfer_type_rx = dma_spec->args[1];

		data.channel = dma_spec->args[2];

	} else {

		return NULL;

	}



	if (data.channel > -1) {

		if (data.channel >= jzdma->soc_data->nb_channels) {
@@ -822,7 +837,8 @@ static struct dma_chan *jz4780_of_dma_xlate(struct of_phandle_args *dma_spec, 
			return NULL;

		}



		jzdma->chan[data.channel].transfer_type = data.transfer_type;

		jzdma->chan[data.channel].transfer_type_tx = data.transfer_type_tx;

		jzdma->chan[data.channel].transfer_type_rx = data.transfer_type_rx;



		return dma_get_slave_channel(

			&jzdma->chan[data.channel].vchan.chan);