From 9a6cecc846169159bfce511f4c0034bb96eea1ca Mon Sep 17 00:00:00 2001 From: Jon Hunter Date: Fri, 14 Sep 2012 17:41:57 -0500 Subject: dmaengine: add helper function to request a slave DMA channel Currently slave DMA channels are requested by calling dma_request_channel() and requires DMA clients to pass various filter parameters to obtain the appropriate channel. With device-tree being used by architectures such as arm and the addition of device-tree helper functions to extract the relevant DMA client information from device-tree, add a new function to request a slave DMA channel using device-tree. This function is currently a simple wrapper that calls the device-tree of_dma_request_slave_channel() function. Cc: Nicolas Ferre Cc: Benoit Cousson Cc: Stephen Warren Cc: Grant Likely Cc: Russell King Cc: Rob Herring Cc: Arnd Bergmann Cc: Vinod Koul Cc: Dan Williams Acked-by: Arnd Bergmann Signed-off-by: Jon Hunter Reviewed-by: Stephen Warren Acked-by: Rob Herring Signed-off-by: Vinod Koul --- drivers/dma/dmaengine.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) (limited to 'drivers/dma/dmaengine.c') diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c index a815d44c70a4..d37cf95987b6 100644 --- a/drivers/dma/dmaengine.c +++ b/drivers/dma/dmaengine.c @@ -62,6 +62,7 @@ #include #include #include +#include static DEFINE_MUTEX(dma_list_mutex); static DEFINE_IDR(dma_idr); @@ -546,6 +547,21 @@ struct dma_chan *__dma_request_channel(dma_cap_mask_t *mask, dma_filter_fn fn, v } EXPORT_SYMBOL_GPL(__dma_request_channel); +/** + * dma_request_slave_channel - try to allocate an exclusive slave channel + * @dev: pointer to client device structure + * @name: slave channel name + */ +struct dma_chan *dma_request_slave_channel(struct device *dev, char *name) +{ + /* If device-tree is present get slave info from here */ + if (dev->of_node) + return of_dma_request_slave_channel(dev->of_node, name); + + return NULL; +} +EXPORT_SYMBOL_GPL(dma_request_slave_channel); + void dma_release_channel(struct dma_chan *chan) { mutex_lock(&dma_list_mutex); -- cgit v1.2.3 From 2cbe7feba1ac521b5668609c35b94536bbbcd52f Mon Sep 17 00:00:00 2001 From: Bartlomiej Zolnierkiewicz Date: Thu, 8 Nov 2012 10:02:07 +0000 Subject: dmaengine: add cpu_relax() to busy-loop in dma_sync_wait() Removal of the busy-loop from dma_sync_wait() is not a trivial task so just add cpu_relax() to the loop for now. Cc: Vinod Koul Cc: Tomasz Figa Signed-off-by: Bartlomiej Zolnierkiewicz Signed-off-by: Kyungmin Park Signed-off-by: Dan Williams --- drivers/dma/dmaengine.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'drivers/dma/dmaengine.c') diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c index d37cf95987b6..242b8c0a3de8 100644 --- a/drivers/dma/dmaengine.c +++ b/drivers/dma/dmaengine.c @@ -267,7 +267,10 @@ enum dma_status dma_sync_wait(struct dma_chan *chan, dma_cookie_t cookie) pr_err("%s: timeout!\n", __func__); return DMA_ERROR; } - } while (status == DMA_IN_PROGRESS); + if (status != DMA_IN_PROGRESS) + break; + cpu_relax(); + } while (1); return status; } -- cgit v1.2.3 From 69ee266b4c890aea7505388c4e394f5757166531 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Wed, 27 Feb 2013 17:04:03 -0800 Subject: dmaengine: convert to idr_alloc() Convert to the much saner new idr interface. Signed-off-by: Tejun Heo Cc: Dan Williams Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/dma/dmaengine.c | 16 ++++++---------- 1 file changed, 6 insertions(+), 10 deletions(-) (limited to 'drivers/dma/dmaengine.c') diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c index 242b8c0a3de8..b2728d6ba2fd 100644 --- a/drivers/dma/dmaengine.c +++ b/drivers/dma/dmaengine.c @@ -686,18 +686,14 @@ static int get_dma_id(struct dma_device *device) { int rc; - idr_retry: - if (!idr_pre_get(&dma_idr, GFP_KERNEL)) - return -ENOMEM; mutex_lock(&dma_list_mutex); - rc = idr_get_new(&dma_idr, NULL, &device->dev_id); - mutex_unlock(&dma_list_mutex); - if (rc == -EAGAIN) - goto idr_retry; - else if (rc != 0) - return rc; - return 0; + rc = idr_alloc(&dma_idr, NULL, 0, 0, GFP_KERNEL); + if (rc >= 0) + device->dev_id = rc; + + mutex_unlock(&dma_list_mutex); + return rc < 0 ? rc : 0; } /** -- cgit v1.2.3