From mboxrd@z Thu Jan 1 00:00:00 1970 From: Laurent Pinchart Subject: Re: [PATCHv9 6/6] dmaengine: rcar-dmac: add iommu support for slave transfers Date: Mon, 05 Sep 2016 12:52:44 +0300 Message-ID: <6358234.jyTvyVnNF0@avalon> References: <20160810112219.17964-1-niklas.soderlund+renesas@ragnatech.se> <20160810112219.17964-7-niklas.soderlund+renesas@ragnatech.se> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Return-path: In-Reply-To: <20160810112219.17964-7-niklas.soderlund+renesas@ragnatech.se> Sender: linux-renesas-soc-owner@vger.kernel.org To: Niklas =?ISO-8859-1?Q?S=F6derlund?= Cc: linux-renesas-soc@vger.kernel.org, linux-arm-kernel@lists.infradead.org, dmaengine@vger.kernel.org, iommu@lists.linux-foundation.org, linux@armlinux.org.uk, hch@infradead.org, dan.j.williams@intel.com, vinod.koul@intel.com, robin.murphy@arm.com, linus.walleij@linaro.org, arnd@arndb.de List-Id: iommu@lists.linux-foundation.org Hi Niklas, Thank you for the patch. On Wednesday 10 Aug 2016 13:22:19 Niklas S=F6derlund wrote: > Enable slave transfers to a device behind a IPMMU by mapping the slav= e > addresses using the dma-mapping API. >=20 > Signed-off-by: Niklas S=F6derlund > --- > drivers/dma/sh/rcar-dmac.c | 82 +++++++++++++++++++++++++++++++++++++= +----- > 1 file changed, 74 insertions(+), 8 deletions(-) >=20 > 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 { > }; >=20 > /* > + * struct rcar_dmac_chan_map - Map of slave device phys to dma addre= ss > + * @addr: slave dma address > + * @dir: direction of mapping > + * @slave: slave configuration that is mapped > + */ > +struct rcar_dmac_chan_map { > +=09dma_addr_t addr; > +=09enum dma_data_direction dir; > +=09struct 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 { >=20 > =09struct rcar_dmac_chan_slave src; > =09struct rcar_dmac_chan_slave dst; > +=09struct rcar_dmac_chan_map map; > =09int mid_rid; >=20 > =09spinlock_t lock; > @@ -1029,13 +1042,65 @@ rcar_dmac_prep_dma_memcpy(struct dma_chan *ch= an, > dma_addr_t dma_dest, DMA_MEM_TO_MEM, flags, false); > } >=20 > +static int rcar_dmac_map_slave_addr(struct dma_chan *chan, > +=09=09=09=09 enum dma_transfer_direction dir) > +{ > +=09struct rcar_dmac_chan *rchan =3D to_rcar_dmac_chan(chan); > +=09struct rcar_dmac_chan_map *map =3D &rchan->map; > +=09phys_addr_t dev_addr; > +=09size_t dev_size; > +=09enum dma_data_direction dev_dir; > + > +=09if (dir =3D=3D DMA_DEV_TO_MEM) { > +=09=09dev_addr =3D rchan->src.slave_addr; > +=09=09dev_size =3D rchan->src.xfer_size; > +=09=09dev_dir =3D DMA_TO_DEVICE; Shouldn't this be DMA_FROM_DEVICE, and DMA_TO_DEVICE below ? > +=09} else { > +=09=09dev_addr =3D rchan->dst.slave_addr; > +=09=09dev_size =3D rchan->dst.xfer_size; > +=09=09dev_dir =3D DMA_FROM_DEVICE; > +=09} > + > +=09/* Reuse current map if possible. */ > +=09if (dev_addr =3D=3D map->slave.slave_addr && > +=09 dev_size =3D=3D map->slave.xfer_size && > +=09 dev_dir =3D=3D map->dir) > +=09=09return 0; > + > +=09/* Remove old mapping if present. */ > +=09if (map->slave.xfer_size) > +=09=09dma_unmap_resource(chan->device->dev, map->addr, > +=09=09=09=09 map->slave.xfer_size, map->dir, 0); Unless I'm mistaken the resource will not be unmapped when freeing chan= nel=20 resources, will it ? > +=09map->slave.xfer_size =3D 0; > + > +=09/* Create new slave address map. */ > +=09map->addr =3D dma_map_resource(chan->device->dev, dev_addr, dev_s= ize, > +=09=09=09=09 dev_dir, 0); > + > +=09if (dma_mapping_error(chan->device->dev, map->addr)) { > +=09=09dev_err(chan->device->dev, > +=09=09=09"chan%u: failed to map %zx@%pap", rchan->index, > +=09=09=09dev_size, &dev_addr); > +=09=09return -EIO; > +=09} > + > +=09dev_dbg(chan->device->dev, "chan%u: map %zx@%pap to %pad dir: %s\= n", > +=09=09rchan->index, dev_size, &dev_addr, &map->addr, > +=09=09dev_dir =3D=3D DMA_TO_DEVICE ? "DMA_TO_DEVICE" :=20 "DMA_FROM_DEVICE"); > + > +=09map->slave.slave_addr =3D dev_addr; > +=09map->slave.xfer_size =3D dev_size; > +=09map->dir =3D dev_dir; > + > +=09return 0; > +} > + > static struct dma_async_tx_descriptor * > rcar_dmac_prep_slave_sg(struct dma_chan *chan, struct scatterlist *s= gl, > =09=09=09unsigned int sg_len, enum dma_transfer_direction dir, > =09=09=09unsigned long flags, void *context) > { > =09struct rcar_dmac_chan *rchan =3D to_rcar_dmac_chan(chan); > -=09dma_addr_t dev_addr; >=20 > =09/* Someone calling slave DMA on a generic channel? */ > =09if (rchan->mid_rid < 0 || !sg_len) { > @@ -1045,9 +1110,10 @@ rcar_dmac_prep_slave_sg(struct dma_chan *chan,= struct > scatterlist *sgl, return NULL; > =09} >=20 > -=09dev_addr =3D dir =3D=3D DMA_DEV_TO_MEM > -=09=09 ? rchan->src.slave_addr : rchan->dst.slave_addr; > -=09return rcar_dmac_chan_prep_sg(rchan, sgl, sg_len, dev_addr, > +=09if (rcar_dmac_map_slave_addr(chan, dir)) > +=09=09return NULL; > + > +=09return rcar_dmac_chan_prep_sg(rchan, sgl, sg_len, rchan->map.addr= , > =09=09=09=09 dir, flags, false); > } >=20 > @@ -1061,7 +1127,6 @@ rcar_dmac_prep_dma_cyclic(struct dma_chan *chan= , > dma_addr_t buf_addr, struct rcar_dmac_chan *rchan =3D > to_rcar_dmac_chan(chan); > =09struct dma_async_tx_descriptor *desc; > =09struct scatterlist *sgl; > -=09dma_addr_t dev_addr; > =09unsigned int sg_len; > =09unsigned int i; >=20 > @@ -1073,6 +1138,9 @@ rcar_dmac_prep_dma_cyclic(struct dma_chan *chan= , > dma_addr_t buf_addr, return NULL; > =09} >=20 > +=09if (rcar_dmac_map_slave_addr(chan, dir)) > +=09=09return NULL; > + > =09sg_len =3D buf_len / period_len; > =09if (sg_len > RCAR_DMAC_MAX_SG_LEN) { > =09=09dev_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]) =3D period_len; > =09} >=20 > -=09dev_addr =3D dir =3D=3D DMA_DEV_TO_MEM > -=09=09 ? rchan->src.slave_addr : rchan->dst.slave_addr; > -=09desc =3D rcar_dmac_chan_prep_sg(rchan, sgl, sg_len, dev_addr, > +=09desc =3D rcar_dmac_chan_prep_sg(rchan, sgl, sg_len, rchan->map.ad= dr, > =09=09=09=09 dir, flags, true); >=20 > =09kfree(sgl); --=20 Regards, Laurent Pinchart