From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?UTF-8?q?Niklas=20S=C3=B6derlund?= Subject: [PATCHv7 6/6] dmaengine: rcar-dmac: add iommu support for slave transfers Date: Wed, 1 Jun 2016 17:22:29 +0200 Message-ID: <1464794549-6601-7-git-send-email-niklas.soderlund+renesas@ragnatech.se> References: <1464794549-6601-1-git-send-email-niklas.soderlund+renesas@ragnatech.se> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <1464794549-6601-1-git-send-email-niklas.soderlund+renesas@ragnatech.se> Sender: linux-renesas-soc-owner@vger.kernel.org To: hch@infradead.org, linux-renesas-soc@vger.kernel.org, linux-arm-kernel@lists.infradead.org, dmaengine@vger.kernel.org, iommu@lists.linux-foundation.org Cc: dan.j.williams@intel.com, vinod.koul@intel.com, robin.murphy@arm.com, laurent.pinchart@ideasonboard.com, linus.walleij@linaro.org, arnd@arndb.de, =?UTF-8?q?Niklas=20S=C3=B6derlund?= List-Id: iommu@lists.linux-foundation.org Enable slave transfers to a device behind a IPMMU by mapping the slave addresses using the dma-mapping API. Signed-off-by: Niklas S=C3=B6derlund --- 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 b0c3bb2..8592598 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 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 { =20 struct rcar_dmac_chan_slave src; struct rcar_dmac_chan_slave dst; + struct rcar_dmac_chan_map map; int mid_rid; =20 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); } =20 +static int rcar_dmac_map_slave_addr(struct dma_chan *chan, + enum dma_transfer_direction dir) +{ + struct rcar_dmac_chan *rchan =3D to_rcar_dmac_chan(chan); + struct rcar_dmac_chan_map *map =3D &rchan->map; + phys_addr_t dev_addr; + size_t dev_size; + enum dma_data_direction dev_dir; + + if (dir =3D=3D DMA_DEV_TO_MEM) { + dev_addr =3D rchan->src.slave_addr; + dev_size =3D rchan->src.xfer_size; + dev_dir =3D DMA_TO_DEVICE; + } else { + dev_addr =3D rchan->dst.slave_addr; + dev_size =3D rchan->dst.xfer_size; + dev_dir =3D DMA_FROM_DEVICE; + } + + /* Reuse current map if possible. */ + if (dev_addr =3D=3D map->slave.slave_addr && + dev_size =3D=3D map->slave.xfer_size && + dev_dir =3D=3D 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 =3D 0; + + /* Create new slave address map. */ + map->addr =3D 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 =3D=3D DMA_TO_DEVICE ? "DMA_TO_DEVICE" : "DMA_FROM_DEVICE"); + + map->slave.slave_addr =3D dev_addr; + map->slave.xfer_size =3D dev_size; + map->dir =3D 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 =3D to_rcar_dmac_chan(chan); - dma_addr_t dev_addr; =20 /* 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, s= truct scatterlist *sgl, return NULL; } =20 - dev_addr =3D dir =3D=3D 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); } =20 @@ -1059,7 +1125,6 @@ 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); struct dma_async_tx_descriptor *desc; struct scatterlist *sgl; - dma_addr_t dev_addr; unsigned int sg_len; unsigned int i; =20 @@ -1071,6 +1136,9 @@ rcar_dmac_prep_dma_cyclic(struct dma_chan *chan, = dma_addr_t buf_addr, return NULL; } =20 + if (rcar_dmac_map_slave_addr(chan, dir)) + return NULL; + sg_len =3D 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]) =3D period_len; } =20 - dev_addr =3D dir =3D=3D DMA_DEV_TO_MEM - ? rchan->src.slave_addr : rchan->dst.slave_addr; - desc =3D rcar_dmac_chan_prep_sg(rchan, sgl, sg_len, dev_addr, + desc =3D rcar_dmac_chan_prep_sg(rchan, sgl, sg_len, rchan->map.addr, dir, flags, true); =20 kfree(sgl); --=20 2.8.2