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. > > Signed-off-by: Guennadi Liakhovetski <[email protected]> > --- > 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 > 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);
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