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authorArnd Bergmann <arnd@arndb.de>2015-02-17 01:46:49 +0000
committerVinod Koul <vinod.koul@intel.com>2015-02-23 16:12:24 +0530
commit411fdaf846afb0be1b54383c184f58a42fa416ff (patch)
tree2460b59f2c049f6e47c59d67f8c2f18c4be23b33 /drivers/dma/sh
parentc517d838eb7d07bbe9507871fab3931deccff539 (diff)
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>
Diffstat (limited to 'drivers/dma/sh')
-rw-r--r--drivers/dma/sh/shdma-base.c73
1 files changed, 53 insertions, 20 deletions
diff --git a/drivers/dma/sh/shdma-base.c b/drivers/dma/sh/shdma-base.c
index 8ee383d339a5..10fcabad80f3 100644
--- a/drivers/dma/sh/shdma-base.c
+++ b/drivers/dma/sh/shdma-base.c
@@ -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)
+ schan = to_shdma_chan(chan);
+ 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;
+ }
- schan = to_shdma_chan(chan);
- if (!schan->dev->of_node && match >= slave_num)
+ 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);
}