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dmaengine: shdma: use normal interface for passing slave id 

in dma_slave_config, which is incompatible with the way that the
dmaengine API normally works.

I've had a closer look at the existing code now and found that all
slave drivers that pass a slave_id in dma_slave_config for SH do that
right after passing the same ID into shdma_chan_filter, so we can just
rely on that. However, the various shdma drivers currently do not
remember the slave ID that was passed into the filter function when
used in non-DT mode and only check the value to find a matching channel,
unlike all other drivers.

There might still be drivers that are not part of the kernel that rely
on setting the slave_id to some other value, so to be on the safe side,
this adds another 'real_slave_id' field to shdma_chan that remembers
the ID and uses it when a driver passes a zero slave_id in dma_slave_config,
like most drivers do.

Eventually, the real_slave_id and slave_id fields should just get merged
into one field, but that requires other changes.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
This commit is contained in:
Arnd Bergmann 2015-02-17 01:46:49 +00:00 committed by Vinod Koul
parent c517d838eb
commit 411fdaf846
2 changed files with 56 additions and 22 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

77
drivers/dma/sh/shdma-base.c
View File

@ -171,8 +171,7 @@ 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,
dma_addr_t slave_addr)
static int shdma_setup_slave(struct shdma_chan *schan, dma_addr_t slave_addr)
{
struct shdma_dev *sdev = to_shdma_dev(schan->dma_chan.device);
const struct shdma_ops *ops = sdev->ops;
@ -183,25 +182,23 @@ static int shdma_setup_slave(struct shdma_chan *schan, int slave_id,
ret = ops->set_slave(schan, match, slave_addr, true);
if (ret < 0)
return ret;
slave_id = schan->slave_id;
} else {
match = slave_id;
match = schan->real_slave_id;
}
if (slave_id < 0 || slave_id >= slave_num)
if (schan->real_slave_id < 0 || schan->real_slave_id >= slave_num)
return -EINVAL;
if (test_and_set_bit(slave_id, shdma_slave_used))
if (test_and_set_bit(schan->real_slave_id, shdma_slave_used))
return -EBUSY;
ret = ops->set_slave(schan, match, slave_addr, false);
if (ret < 0) {
clear_bit(slave_id, shdma_slave_used);
clear_bit(schan->real_slave_id, shdma_slave_used);
return ret;
}
schan->slave_id = slave_id;
schan->slave_id = schan->real_slave_id;
return 0;
}
@ -221,10 +218,12 @@ static int shdma_alloc_chan_resources(struct dma_chan *chan)
*/
if (slave) {
/* Legacy mode: .private is set in filter */
ret = shdma_setup_slave(schan, slave->slave_id, 0);
schan->real_slave_id = slave->slave_id;
ret = shdma_setup_slave(schan, 0);
if (ret < 0)
goto esetslave;
} else {
/* Normal mode: real_slave_id was set by filter */
schan->slave_id = -EINVAL;
}
@ -258,11 +257,14 @@ esetslave:
/*
* 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
* "old" method, using the .private pointer.
* You always have to pass a valid slave id as the argument, old drivers that
* pass ERR_PTR(-EINVAL) as a filter parameter and set it up in dma_slave_config
* need to be updated so we can remove the slave_id field from dma_slave_config.
* 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.
* .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
@ -276,7 +278,7 @@ bool shdma_chan_filter(struct dma_chan *chan, void *arg)
{
struct shdma_chan *schan;
struct shdma_dev *sdev;
int match = (long)arg;
int slave_id = (long)arg;
int ret;
/* Only support channels handled by this driver. */
@ -284,19 +286,39 @@ bool shdma_chan_filter(struct dma_chan *chan, void *arg)
shdma_alloc_chan_resources)
return false;
if (match < 0)
/* No slave requested - arbitrary channel */
return true;
schan = to_shdma_chan(chan);
if (!schan->dev->of_node && match >= slave_num)
sdev = to_shdma_dev(chan->device);
/*
* For DT, the schan->slave_id field is generated by the
* set_slave function from the slave ID that is passed in
* from xlate. For the non-DT case, the slave ID is
* directly passed into the filter function by the driver
*/
if (schan->dev->of_node) {
ret = sdev->ops->set_slave(schan, slave_id, 0, true);
if (ret < 0)
return false;
schan->real_slave_id = schan->slave_id;
return true;
}
if (slave_id < 0) {
/* No slave requested - arbitrary channel */
dev_warn(sdev->dma_dev.dev, "invalid slave ID passed to dma_request_slave\n");
return true;
}
if (slave_id >= slave_num)
return false;
sdev = to_shdma_dev(schan->dma_chan.device);
ret = sdev->ops->set_slave(schan, match, 0, true);
ret = sdev->ops->set_slave(schan, slave_id, 0, true);
if (ret < 0)
return false;
schan->real_slave_id = slave_id;
return true;
}
EXPORT_SYMBOL(shdma_chan_filter);
@ -452,6 +474,8 @@ static void shdma_free_chan_resources(struct dma_chan *chan)
chan->private = NULL;
}
schan->real_slave_id = 0;
spin_lock_irq(&schan->chan_lock);
list_splice_init(&schan->ld_free, &list);
@ -764,11 +788,20 @@ static int shdma_config(struct dma_chan *chan,
*/
if (!config)
return -EINVAL;
/*
* overriding the slave_id through dma_slave_config is deprecated,
* but possibly some out-of-tree drivers still do it.
*/
if (WARN_ON_ONCE(config->slave_id &&
config->slave_id != schan->real_slave_id))
schan->real_slave_id = config->slave_id;
/*
* We could lock this, but you shouldn't be configuring the
* channel, while using it...
*/
return shdma_setup_slave(schan, config->slave_id,
return shdma_setup_slave(schan,
config->direction == DMA_DEV_TO_MEM ?
config->src_addr : config->dst_addr);
}

1
include/linux/shdma-base.h
View File

@ -69,6 +69,7 @@ struct shdma_chan {
int id; /* Raw id of this channel */
int irq; /* Channel IRQ */
int slave_id; /* Client ID for slave DMA */
int real_slave_id; /* argument passed to filter function */
int hw_req; /* DMA request line for slave DMA - same
* as MID/RID, used with DT */
enum shdma_pm_state pm_state;