Hi Niklas,
Thank you for the patch.
On Wednesday 10 Aug 2016 13:22:19 Niklas Söderlund wrote:
> 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@xxxxxxxxxxxx>
> ---
> 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 cf983a9..22a5e40 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;
> @@ -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;
Shouldn't this be DMA_FROM_DEVICE, and DMA_TO_DEVICE below ?
> + } 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);
Unless I'm mistaken the resource will not be unmapped when freeing channel
resources, will it ?
> + 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);
--
Regards,
Laurent Pinchart
