dmaengine: Add privatecnt to revert DMA_PRIVATE property
Currently dma_request_channel() set DMA_PRIVATE capability but never
clear it. So if a public channel was once grabbed by
dma_request_channel(), the device stay PRIVATE forever. Add
privatecnt member to dma_device to correctly revert it.
[lg@denx.de: fix bad usage of 'chan' in dma_async_device_register]
Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Acked-by: Maciej Sosnowski <maciej.sosnowski@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c
index a41d1ea..92438e9 100644
--- a/drivers/dma/dmaengine.c
+++ b/drivers/dma/dmaengine.c
@@ -507,6 +507,7 @@
* published in the general-purpose allocator
*/
dma_cap_set(DMA_PRIVATE, device->cap_mask);
+ device->privatecnt++;
err = dma_chan_get(chan);
if (err == -ENODEV) {
@@ -518,6 +519,8 @@
dma_chan_name(chan), err);
else
break;
+ if (--device->privatecnt == 0)
+ dma_cap_clear(DMA_PRIVATE, device->cap_mask);
chan->private = NULL;
chan = NULL;
}
@@ -537,6 +540,9 @@
WARN_ONCE(chan->client_count != 1,
"chan reference count %d != 1\n", chan->client_count);
dma_chan_put(chan);
+ /* drop PRIVATE cap enabled by __dma_request_channel() */
+ if (--chan->device->privatecnt == 0)
+ dma_cap_clear(DMA_PRIVATE, chan->device->cap_mask);
chan->private = NULL;
mutex_unlock(&dma_list_mutex);
}
@@ -719,6 +725,8 @@
}
}
list_add_tail_rcu(&device->global_node, &dma_device_list);
+ if (dma_has_cap(DMA_PRIVATE, device->cap_mask))
+ device->privatecnt++; /* Always private */
dma_channel_rebalance();
mutex_unlock(&dma_list_mutex);
diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
index 2afc2c9..2e2aa3d 100644
--- a/include/linux/dmaengine.h
+++ b/include/linux/dmaengine.h
@@ -202,6 +202,7 @@
/**
* struct dma_device - info on the entity supplying DMA services
* @chancnt: how many DMA channels are supported
+ * @privatecnt: how many DMA channels are requested by dma_request_channel
* @channels: the list of struct dma_chan
* @global_node: list_head for global dma_device_list
* @cap_mask: one or more dma_capability flags
@@ -224,6 +225,7 @@
struct dma_device {
unsigned int chancnt;
+ unsigned int privatecnt;
struct list_head channels;
struct list_head global_node;
dma_cap_mask_t cap_mask;
@@ -352,6 +354,13 @@
set_bit(tx_type, dstp->bits);
}
+#define dma_cap_clear(tx, mask) __dma_cap_clear((tx), &(mask))
+static inline void
+__dma_cap_clear(enum dma_transaction_type tx_type, dma_cap_mask_t *dstp)
+{
+ clear_bit(tx_type, dstp->bits);
+}
+
#define dma_cap_zero(mask) __dma_cap_zero(&(mask))
static inline void __dma_cap_zero(dma_cap_mask_t *dstp)
{
