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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: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
This commit is contained in:
Niklas Söderlund 2016-08-10 13:22:19 +02:00 committed by Vinod Koul
parent c5ed08e988
commit 9f878603db
1 changed files with 74 additions and 8 deletions
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82
drivers/dma/sh/rcar-dmac.c
View File

@ -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);