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+rene...@ragnatech.se>
---
drivers/dma/sh/rcar-dmac.c | 82 +++++++++++++++++++++++++++++++++++++++++-----
1 file changed, 74 insertions(+), 8 deletions(-)
diff --git a/drivers/dma/sh/rcar-dmac.c b/drivers/dma/sh/rcar-dmac.c
index b3911fe..56816e3 100644
--- a/drivers/dma/sh/rcar-dmac.c
+++ b/drivers/dma/sh/rcar-dmac.c
@@ -128,6 +128,18 @@ struct rcar_dmac_chan_slave {
};
/*
+ * 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
* @iomem: channel I/O memory base
@@ -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;
@@ -1027,13 +1040,65 @@ 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, NULL);
+ map->slave.xfer_size = 0;
+
+ /* Create new slave address map. */
+ map->addr = dma_map_resource(chan->device->dev, dev_addr, dev_size,
+ dev_dir, NULL);
+
+ 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) {
@@ -1043,9 +1108,10 @@ 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);
}
@@ -1059,7 +1125,6 @@ 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;
@@ -1071,6 +1136,9 @@ 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,
@@ -1098,9 +1166,7 @@ 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);
--
2.7.2
