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Commit 9f878603 authored by Niklas Söderlund's avatar Niklas Söderlund Committed by Vinod Koul
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dmaengine: rcar-dmac: add iommu support for slave transfers 



Enable slave transfers to a device behind a IPMMU by mapping the slave
addresses using the dma-mapping API.

Signed-off-by: default avatarNiklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Acked-by: default avatarArnd Bergmann <arnd@arndb.de>
Signed-off-by: default avatarVinod Koul <vinod.koul@intel.com>
parent c5ed08e9

drivers/dma/sh/rcar-dmac.c

+74 −8
Original line number Diff line number Diff line
@@ -127,6 +127,18 @@ struct rcar_dmac_chan_slave { 
	unsigned int xfer_size;

};



/*

 * struct rcar_dmac_chan_map - Map of slave device phys to dma address

 * @addr: slave dma address

 * @dir: direction of mapping

 * @slave: slave configuration that is mapped

 */

struct rcar_dmac_chan_map {

	dma_addr_t addr;

	enum dma_data_direction dir;

	struct rcar_dmac_chan_slave slave;

};



/*

 * struct rcar_dmac_chan - R-Car Gen2 DMA Controller Channel

 * @chan: base DMA channel object
@@ -152,6 +164,7 @@ struct rcar_dmac_chan { 


	struct rcar_dmac_chan_slave src;

	struct rcar_dmac_chan_slave dst;

	struct rcar_dmac_chan_map map;

	int mid_rid;



	spinlock_t lock;
@@ -1029,13 +1042,65 @@ rcar_dmac_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dma_dest, 
				      DMA_MEM_TO_MEM, flags, false);

}



static int rcar_dmac_map_slave_addr(struct dma_chan *chan,

				    enum dma_transfer_direction dir)

{

	struct rcar_dmac_chan *rchan = to_rcar_dmac_chan(chan);

	struct rcar_dmac_chan_map *map = &rchan->map;

	phys_addr_t dev_addr;

	size_t dev_size;

	enum dma_data_direction dev_dir;



	if (dir == DMA_DEV_TO_MEM) {

		dev_addr = rchan->src.slave_addr;

		dev_size = rchan->src.xfer_size;

		dev_dir = DMA_TO_DEVICE;

	} else {

		dev_addr = rchan->dst.slave_addr;

		dev_size = rchan->dst.xfer_size;

		dev_dir = DMA_FROM_DEVICE;

	}



	/* Reuse current map if possible. */

	if (dev_addr == map->slave.slave_addr &&

	    dev_size == map->slave.xfer_size &&

	    dev_dir == map->dir)

		return 0;



	/* Remove old mapping if present. */

	if (map->slave.xfer_size)

		dma_unmap_resource(chan->device->dev, map->addr,

				   map->slave.xfer_size, map->dir, 0);

	map->slave.xfer_size = 0;



	/* Create new slave address map. */

	map->addr = dma_map_resource(chan->device->dev, dev_addr, dev_size,

				     dev_dir, 0);



	if (dma_mapping_error(chan->device->dev, map->addr)) {

		dev_err(chan->device->dev,

			"chan%u: failed to map %zx@%pap", rchan->index,

			dev_size, &dev_addr);

		return -EIO;

	}



	dev_dbg(chan->device->dev, "chan%u: map %zx@%pap to %pad dir: %s\n",

		rchan->index, dev_size, &dev_addr, &map->addr,

		dev_dir == DMA_TO_DEVICE ? "DMA_TO_DEVICE" : "DMA_FROM_DEVICE");



	map->slave.slave_addr = dev_addr;

	map->slave.xfer_size = dev_size;

	map->dir = dev_dir;



	return 0;

}



static struct dma_async_tx_descriptor *

rcar_dmac_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,

			unsigned int sg_len, enum dma_transfer_direction dir,

			unsigned long flags, void *context)

{

	struct rcar_dmac_chan *rchan = to_rcar_dmac_chan(chan);

	dma_addr_t dev_addr;



	/* Someone calling slave DMA on a generic channel? */

	if (rchan->mid_rid < 0 || !sg_len) {
@@ -1045,9 +1110,10 @@ rcar_dmac_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl, 
		return NULL;

	}



	dev_addr = dir == DMA_DEV_TO_MEM

		 ? rchan->src.slave_addr : rchan->dst.slave_addr;

	return rcar_dmac_chan_prep_sg(rchan, sgl, sg_len, dev_addr,

	if (rcar_dmac_map_slave_addr(chan, dir))

		return NULL;



	return rcar_dmac_chan_prep_sg(rchan, sgl, sg_len, rchan->map.addr,

				      dir, flags, false);

}
@@ -1061,7 +1127,6 @@ rcar_dmac_prep_dma_cyclic(struct dma_chan *chan, dma_addr_t buf_addr, 
	struct rcar_dmac_chan *rchan = to_rcar_dmac_chan(chan);

	struct dma_async_tx_descriptor *desc;

	struct scatterlist *sgl;

	dma_addr_t dev_addr;

	unsigned int sg_len;

	unsigned int i;
@@ -1073,6 +1138,9 @@ rcar_dmac_prep_dma_cyclic(struct dma_chan *chan, dma_addr_t buf_addr, 
		return NULL;

	}



	if (rcar_dmac_map_slave_addr(chan, dir))

		return NULL;



	sg_len = buf_len / period_len;

	if (sg_len > RCAR_DMAC_MAX_SG_LEN) {

		dev_err(chan->device->dev,
@@ -1100,9 +1168,7 @@ rcar_dmac_prep_dma_cyclic(struct dma_chan *chan, dma_addr_t buf_addr, 
		sg_dma_len(&sgl[i]) = period_len;

	}



	dev_addr = dir == DMA_DEV_TO_MEM

		 ? rchan->src.slave_addr : rchan->dst.slave_addr;

	desc = rcar_dmac_chan_prep_sg(rchan, sgl, sg_len, dev_addr,

	desc = rcar_dmac_chan_prep_sg(rchan, sgl, sg_len, rchan->map.addr,

				      dir, flags, true);



	kfree(sgl);