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+renesas@xxxxxxxxxxxx>
---
drivers/dma/sh/rcar-dmac.c | 59 ++++++++++++++++++++++++++++++++++++++++++----
1 file changed, 54 insertions(+), 5 deletions(-)
diff --git a/drivers/dma/sh/rcar-dmac.c b/drivers/dma/sh/rcar-dmac.c
index 743873c..f3ec8a6 100644
--- a/drivers/dma/sh/rcar-dmac.c
+++ b/drivers/dma/sh/rcar-dmac.c
@@ -1106,21 +1106,70 @@ rcar_dmac_prep_dma_cyclic(struct dma_chan *chan, dma_addr_t buf_addr,
return desc;
}
+static int __rcar_dmac_device_config(struct dma_chan *chan,
+ struct rcar_dmac_chan_slave *slave,
+ phys_addr_t addr, size_t size,
+ enum dma_data_direction dir,
+ struct dma_attrs *attrs)
+{
+ struct rcar_dmac_chan *rchan = to_rcar_dmac_chan(chan);
+ struct page *page;
+ size_t offset;
+
+ /* unmap old */
+ if (slave->slave_addr) {
+ dma_unmap_page_attrs(chan->device->dev, slave->slave_addr,
+ slave->xfer_size, dir, attrs);
+ slave->slave_addr = 0;
+ slave->xfer_size = 0;
+ }
+
+ /* map new */
+ if (addr) {
+ /* phys_to_page not available on all platforms */
+ page = pfn_to_page(addr >> PAGE_SHIFT);
+ offset = addr - page_to_phys(page);
+ slave->slave_addr = dma_map_page_attrs(chan->device->dev, page,
+ offset, size, dir, attrs);
+
+ if (dma_mapping_error(chan->device->dev, slave->slave_addr)) {
+ 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);
+ struct dma_attrs attrs;
+ 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;
+ init_dma_attrs(&attrs);
+ dma_set_attr(DMA_ATTR_NO_KERNEL_MAPPING, &attrs);
+ dma_set_attr(DMA_ATTR_SKIP_CPU_SYNC, &attrs);
+
+ ret = __rcar_dmac_device_config(chan, &rchan->src, cfg->src_addr,
+ cfg->src_addr_width, DMA_FROM_DEVICE, &attrs);
+ if (!ret)
+ return ret;
+
+ ret = __rcar_dmac_device_config(chan, &rchan->dst, cfg->dst_addr,
+ cfg->dst_addr_width, DMA_TO_DEVICE, &attrs);
+ return ret;
}
static int rcar_dmac_chan_terminate_all(struct dma_chan *chan)
--
2.7.0
--
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