Enable slave transfers to devices behind IPMMU:s 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 | 57 ++++++++++++++++++++++++++++++++++++++++++----
1 file changed, 52 insertions(+), 5 deletions(-)
diff --git a/drivers/dma/sh/rcar-dmac.c b/drivers/dma/sh/rcar-dmac.c
index 743873c..268407c 100644
--- a/drivers/dma/sh/rcar-dmac.c
+++ b/drivers/dma/sh/rcar-dmac.c
@@ -1106,21 +1106,68 @@ rcar_dmac_prep_dma_cyclic(struct dma_chan *chan,
dma_addr_t buf_addr,
return desc;
}
+static int rcar_dmac_set_slave_addr(struct dma_chan *chan,
+ struct rcar_dmac_chan_slave *slave,
+ phys_addr_t addr, size_t size)
+{
+ struct dma_attrs attrs;
+ enum dma_data_direction dir;
+
+ init_dma_attrs(&attrs);
+ dma_set_attr(DMA_ATTR_NO_KERNEL_MAPPING, &attrs);
+ dma_set_attr(DMA_ATTR_SKIP_CPU_SYNC, &attrs);
+
+ /*
+ * We can't know the direction at this time, see documentation for
+ * 'direction' in struct dma_slave_config.
+ */
+ dir = DMA_BIDIRECTIONAL;
+
+ if (slave->xfer_size) {
+ dma_unmap_resource(chan->device->dev, slave->slave_addr,
+ slave->xfer_size, dir, &attrs);
+ slave->slave_addr = 0;
+ slave->xfer_size = 0;
+ }
+
+ if (size) {
+ slave->slave_addr = dma_map_resource(chan->device->dev, addr,
+ size, dir, &attrs);
+
+ if (dma_mapping_error(chan->device->dev, slave->slave_addr)) {
+ struct rcar_dmac_chan *rchan = to_rcar_dmac_chan(chan);
+
+ dev_err(chan->device->dev,
+ "chan%u: failed to map %zx@%pap",
+ rchan->index, size, &addr);
+ return -EIO;
+ }
+
+ slave->xfer_size = size;
+ }
+
+ return 0;
+}
+
static int rcar_dmac_device_config(struct dma_chan *chan,
struct dma_slave_config *cfg)
{
struct rcar_dmac_chan *rchan = to_rcar_dmac_chan(chan);
+ int ret;
/*
* We could lock this, but you shouldn't be configuring the
* channel, while using it...
*/
- rchan->src.slave_addr = cfg->src_addr;
- rchan->dst.slave_addr = cfg->dst_addr;
- rchan->src.xfer_size = cfg->src_addr_width;
- rchan->dst.xfer_size = cfg->dst_addr_width;
- return 0;
+ ret = rcar_dmac_set_slave_addr(chan, &rchan->src, cfg->src_addr,
+ cfg->src_addr_width);
+ if (ret)
+ return ret;
+
+ ret = rcar_dmac_set_slave_addr(chan, &rchan->dst, cfg->dst_addr,
+ cfg->dst_addr_width);
+ return ret;
}
static int rcar_dmac_chan_terminate_all(struct dma_chan *chan)
--
2.7.1
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