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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
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+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);