diff options
| -rw-r--r-- | drivers/dma/dmaengine.c | 37 | ||||
| -rw-r--r-- | include/linux/dmaengine.h | 4 |
2 files changed, 35 insertions, 6 deletions
diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c index 51a2f2b1b2de..f3ef4edd4de1 100644 --- a/drivers/dma/dmaengine.c +++ b/drivers/dma/dmaengine.c @@ -60,6 +60,8 @@ static long dmaengine_ref_count; /* --- sysfs implementation --- */ +#define DMA_SLAVE_NAME "slave" + /** * dev_to_dma_chan - convert a device pointer to its sysfs container object * @dev - device node @@ -730,11 +732,11 @@ struct dma_chan *dma_request_chan(struct device *dev, const char *name) if (has_acpi_companion(dev) && !chan) chan = acpi_dma_request_slave_chan_by_name(dev, name); - if (chan) { - /* Valid channel found or requester needs to be deferred */ - if (!IS_ERR(chan) || PTR_ERR(chan) == -EPROBE_DEFER) - return chan; - } + if (PTR_ERR(chan) == -EPROBE_DEFER) + return chan; + + if (!IS_ERR_OR_NULL(chan)) + goto found; /* Try to find the channel via the DMA filter map(s) */ mutex_lock(&dma_list_mutex); @@ -754,7 +756,23 @@ struct dma_chan *dma_request_chan(struct device *dev, const char *name) } mutex_unlock(&dma_list_mutex); - return chan ? chan : ERR_PTR(-EPROBE_DEFER); + if (!IS_ERR_OR_NULL(chan)) + goto found; + + return ERR_PTR(-EPROBE_DEFER); + +found: + chan->slave = dev; + chan->name = kasprintf(GFP_KERNEL, "dma:%s", name); + if (!chan->name) + return ERR_PTR(-ENOMEM); + + if (sysfs_create_link(&chan->dev->device.kobj, &dev->kobj, + DMA_SLAVE_NAME)) + dev_err(dev, "Cannot create DMA %s symlink\n", DMA_SLAVE_NAME); + if (sysfs_create_link(&dev->kobj, &chan->dev->device.kobj, chan->name)) + dev_err(dev, "Cannot create DMA %s symlink\n", chan->name); + return chan; } EXPORT_SYMBOL_GPL(dma_request_chan); @@ -812,6 +830,13 @@ void dma_release_channel(struct dma_chan *chan) /* drop PRIVATE cap enabled by __dma_request_channel() */ if (--chan->device->privatecnt == 0) dma_cap_clear(DMA_PRIVATE, chan->device->cap_mask); + if (chan->slave) { + sysfs_remove_link(&chan->slave->kobj, chan->name); + kfree(chan->name); + chan->name = NULL; + chan->slave = NULL; + } + sysfs_remove_link(&chan->dev->device.kobj, DMA_SLAVE_NAME); mutex_unlock(&dma_list_mutex); } EXPORT_SYMBOL_GPL(dma_release_channel); diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h index f52f274773ed..fef69a9c5824 100644 --- a/include/linux/dmaengine.h +++ b/include/linux/dmaengine.h @@ -294,10 +294,12 @@ struct dma_router { /** * struct dma_chan - devices supply DMA channels, clients use them * @device: ptr to the dma device who supplies this channel, always !%NULL + * @slave: ptr to the device using this channel * @cookie: last cookie value returned to client * @completed_cookie: last completed cookie for this channel * @chan_id: channel ID for sysfs * @dev: class device for sysfs + * @name: backlink name for sysfs * @device_node: used to add this to the device chan list * @local: per-cpu pointer to a struct dma_chan_percpu * @client_count: how many clients are using this channel @@ -308,12 +310,14 @@ struct dma_router { */ struct dma_chan { struct dma_device *device; + struct device *slave; dma_cookie_t cookie; dma_cookie_t completed_cookie; /* sysfs */ int chan_id; struct dma_chan_dev *dev; + const char *name; struct list_head device_node; struct dma_chan_percpu __percpu *local; |