Hi Vinod On Mon, 16 Jul 2012, Vinod Koul wrote:
> On Thu, 2012-07-05 at 12:29 +0200, Guennadi Liakhovetski wrote: > > This patch extends the sh dmaengine driver to support the preferred channel > > selection and configuration method, instead of using the "private" field > > from struct dma_chan. We add a standard filter function to be used by > > slave drivers instead of implementing their own ones, and add support for > > the DMA_SLAVE_CONFIG control operation, which must accompany the new > > channel selection method. We still support the legacy .private channel > > allocation method to cater for a smooth driver migration. > There seem to be two things done in this patch, one is to provide a > filter function for people to use for channel filtering, and second the > removal of .private. It would be good to split these two. No, please, see the patch description. This patch only provides a filter function. It does _not_ remove the use of .private yet. First all client drivers have to be ported over to use the new filter + slave-config scheme, only then will the driver be able to drop support for .private. > > Signed-off-by: Guennadi Liakhovetski <g.liakhovet...@gmx.de> > > --- > > drivers/dma/sh/shdma-base.c | 114 > > +++++++++++++++++++++++++++++++++--------- > > drivers/dma/sh/shdma.c | 5 +- > > include/linux/sh_dma.h | 2 + > > include/linux/shdma-base.h | 2 +- > > 4 files changed, 95 insertions(+), 28 deletions(-) > > > > diff --git a/drivers/dma/sh/shdma-base.c b/drivers/dma/sh/shdma-base.c > > index 73db282..0c34c73 100644 > > --- a/drivers/dma/sh/shdma-base.c > > +++ b/drivers/dma/sh/shdma-base.c > > @@ -171,6 +171,65 @@ static struct shdma_desc *shdma_get_desc(struct > > shdma_chan *schan) > > return NULL; > > } > > > > +static int shdma_setup_slave(struct shdma_chan *schan, int slave_id) > > +{ > > + struct shdma_dev *sdev = to_shdma_dev(schan->dma_chan.device); > > + const struct shdma_ops *ops = sdev->ops; > > + int ret; > > + > > + if (slave_id < 0 || slave_id >= slave_num) > > + return -EINVAL; > > + > > + if (test_and_set_bit(slave_id, shdma_slave_used)) > > + return -EBUSY; > > + > > + ret = ops->set_slave(schan, slave_id, false); > > + if (ret < 0) { > > + clear_bit(slave_id, shdma_slave_used); > > + return ret; > > + } > > + > > + schan->slave_id = slave_id; > > + > > + return 0; > > +} > > + > > +/* > > + * This is the standard shdma filter function to be used as a replacement > > to the > > + * "old" method, using the .private pointer. If for some reason you > > allocate a > > + * channel without slave data, use something like ERR_PTR(-EINVAL) as a > > filter > > + * parameter. If this filter is used, the slave driver, after calling > > + * dma_request_channel(), will also have to call dmaengine_slave_config() > > with > > + * .slave_id, .direction, and either .src_addr or .dst_addr set. > > + * NOTE: this filter doesn't support multiple DMAC drivers with the > > DMA_SLAVE > > + * capability! If this becomes a requirement, hardware glue drivers, using > > this > > + * services would have to provide their own filters, which first would > > check > > + * the device driver, similar to how other DMAC drivers, e.g., > > sa11x0-dma.c, do > > + * this, and only then, in case of a match, call this common filter. > > + */ > > +bool shdma_chan_filter(struct dma_chan *chan, void *arg) > > +{ > > + struct shdma_chan *schan = to_shdma_chan(chan); > > + struct shdma_dev *sdev = to_shdma_dev(schan->dma_chan.device); > > + const struct shdma_ops *ops = sdev->ops; > > + int slave_id = (int)arg; > > + int ret; > > + > > + if (slave_id < 0) > > + /* No slave requested - arbitrary channel */ > > + return true; > > + > > + if (slave_id >= slave_num) > > + return false; > > + > > + ret = ops->set_slave(schan, slave_id, true); > > + if (ret < 0) > > + return false; > > + > > + return true; > > +} > > +EXPORT_SYMBOL(shdma_chan_filter); > > + > > static int shdma_alloc_chan_resources(struct dma_chan *chan) > > { > > struct shdma_chan *schan = to_shdma_chan(chan); > > @@ -185,21 +244,10 @@ static int shdma_alloc_chan_resources(struct dma_chan > > *chan) > > * never runs concurrently with itself or free_chan_resources. > > */ > > if (slave) { > > - if (slave->slave_id < 0 || slave->slave_id >= slave_num) { > > - ret = -EINVAL; > > - goto evalid; > > - } > > - > > - if (test_and_set_bit(slave->slave_id, shdma_slave_used)) { > > - ret = -EBUSY; > > - goto etestused; > > - } > > - > > - ret = ops->set_slave(schan, slave->slave_id); > > + /* Legacy mode: .private is set in filter */ > > + ret = shdma_setup_slave(schan, slave->slave_id); > > if (ret < 0) > > goto esetslave; > > - > > - schan->slave_id = slave->slave_id; > > } else { > > schan->slave_id = -EINVAL; > > } > > @@ -228,8 +276,6 @@ edescalloc: > > if (slave) > > esetslave: > > clear_bit(slave->slave_id, shdma_slave_used); > > -etestused: > > -evalid: > > chan->private = NULL; > you missed this one Please, see above. Thanks Guennadi > > return ret; > > } > > @@ -587,22 +633,40 @@ static int shdma_control(struct dma_chan *chan, enum > > dma_ctrl_cmd cmd, > > struct shdma_chan *schan = to_shdma_chan(chan); > > struct shdma_dev *sdev = to_shdma_dev(chan->device); > > const struct shdma_ops *ops = sdev->ops; > > + struct dma_slave_config *config; > > unsigned long flags; > > - > > - /* Only supports DMA_TERMINATE_ALL */ > > - if (cmd != DMA_TERMINATE_ALL) > > - return -ENXIO; > > + int ret; > > > > if (!chan) > > return -EINVAL; > > > > - spin_lock_irqsave(&schan->chan_lock, flags); > > - > > - ops->halt_channel(schan); > > - > > - spin_unlock_irqrestore(&schan->chan_lock, flags); > > + switch (cmd) { > > + case DMA_TERMINATE_ALL: > > + spin_lock_irqsave(&schan->chan_lock, flags); > > + ops->halt_channel(schan); > > + spin_unlock_irqrestore(&schan->chan_lock, flags); > > > > - shdma_chan_ld_cleanup(schan, true); > > + shdma_chan_ld_cleanup(schan, true); > > + break; > > + case DMA_SLAVE_CONFIG: > > + /* > > + * So far only .slave_id is used, but the slave drivers are > > + * encouraged to also set a transfer direction and an address. > > + */ > > + if (!arg) > > + return -EINVAL; > > + /* > > + * We could lock this, but you shouldn't be configuring the > > + * channel, while using it... > > + */ > > + config = (struct dma_slave_config*)arg; > > + ret = shdma_setup_slave(schan, config->slave_id); > > + if (ret < 0) > > + return ret; > > + break; > > + default: > > + return -ENXIO; > > + } > > > > return 0; > > } > > diff --git a/drivers/dma/sh/shdma.c b/drivers/dma/sh/shdma.c > > index 9a10d8b..027c9be 100644 > > --- a/drivers/dma/sh/shdma.c > > +++ b/drivers/dma/sh/shdma.c > > @@ -320,7 +320,7 @@ static const struct sh_dmae_slave_config > > *dmae_find_slave( > > } > > > > static int sh_dmae_set_slave(struct shdma_chan *schan, > > - int slave_id) > > + int slave_id, bool try) > > { > > struct sh_dmae_chan *sh_chan = container_of(schan, struct sh_dmae_chan, > > shdma_chan); > > @@ -328,7 +328,8 @@ static int sh_dmae_set_slave(struct shdma_chan *schan, > > if (!cfg) > > return -ENODEV; > > > > - sh_chan->config = cfg; > > + if (!try) > > + sh_chan->config = cfg; > > > > return 0; > > } > > diff --git a/include/linux/sh_dma.h b/include/linux/sh_dma.h > > index 4e83f3e..b64d6be 100644 > > --- a/include/linux/sh_dma.h > > +++ b/include/linux/sh_dma.h > > @@ -99,4 +99,6 @@ struct sh_dmae_pdata { > > #define CHCR_TE 0x00000002 > > #define CHCR_IE 0x00000004 > > > > +bool shdma_chan_filter(struct dma_chan *chan, void *arg); > > + > > #endif > > diff --git a/include/linux/shdma-base.h b/include/linux/shdma-base.h > > index 6263ad2..93f9821 100644 > > --- a/include/linux/shdma-base.h > > +++ b/include/linux/shdma-base.h > > @@ -93,7 +93,7 @@ struct shdma_ops { > > dma_addr_t (*slave_addr)(struct shdma_chan *); > > int (*desc_setup)(struct shdma_chan *, struct shdma_desc *, > > dma_addr_t, dma_addr_t, size_t *); > > - int (*set_slave)(struct shdma_chan *, int); > > + int (*set_slave)(struct shdma_chan *, int, bool); > > void (*setup_xfer)(struct shdma_chan *, int); > > void (*start_xfer)(struct shdma_chan *, struct shdma_desc *); > > struct shdma_desc *(*embedded_desc)(void *, int); > > > -- > ~Vinod > --- Guennadi Liakhovetski, Ph.D. Freelance Open-Source Software Developer http://www.open-technology.de/ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/