[v2,1/1] dmaengine: hsu: remove excessive lock

Commit Message

Andy Shevchenko July 9, 2015, 10:25 a.m. UTC

All hardware accesses are done under virtual channel lock. That's why specific
channel lock is excessive and can be removed safely. This has been tested on
Intel Medfield and Merrifield.

Signed-off-by: Andy Shevchenko <[e-mail]>
---
 drivers/dma/hsu/hsu.c | 39 ++++-----------------------------------
 drivers/dma/hsu/hsu.h |  1 -
 2 files changed, 4 insertions(+), 36 deletions(-)

Comments

Vinod Koul July 16, 2015, 1:01 p.m. UTC | #1

On Thu, Jul 09, 2015 at 01:25:37PM +0300, Andy Shevchenko wrote:
> All hardware accesses are done under virtual channel lock. That's why specific
> channel lock is excessive and can be removed safely. This has been tested on
> Intel Medfield and Merrifield.

Applied, thanks

Patch

diff --git a/drivers/dma/hsu/hsu.c b/drivers/dma/hsu/hsu.c
index f42f71e..7669c7d 100644
--- a/drivers/dma/hsu/hsu.c
+++ b/drivers/dma/hsu/hsu.c
@@ -99,21 +99,13 @@  static void hsu_dma_chan_start(struct hsu_dma_chan *hsuc)
 
 static void hsu_dma_stop_channel(struct hsu_dma_chan *hsuc)
 {
-	unsigned long flags;
-
-	spin_lock_irqsave(&hsuc->lock, flags);
 	hsu_chan_disable(hsuc);
 	hsu_chan_writel(hsuc, HSU_CH_DCR, 0);
-	spin_unlock_irqrestore(&hsuc->lock, flags);
 }
 
 static void hsu_dma_start_channel(struct hsu_dma_chan *hsuc)
 {
-	unsigned long flags;
-
-	spin_lock_irqsave(&hsuc->lock, flags);
 	hsu_dma_chan_start(hsuc);
-	spin_unlock_irqrestore(&hsuc->lock, flags);
 }
 
 static void hsu_dma_start_transfer(struct hsu_dma_chan *hsuc)
@@ -139,9 +131,9 @@  static u32 hsu_dma_chan_get_sr(struct hsu_dma_chan *hsuc)
 	unsigned long flags;
 	u32 sr;
 
-	spin_lock_irqsave(&hsuc->lock, flags);
+	spin_lock_irqsave(&hsuc->vchan.lock, flags);
 	sr = hsu_chan_readl(hsuc, HSU_CH_SR);
-	spin_unlock_irqrestore(&hsuc->lock, flags);
+	spin_unlock_irqrestore(&hsuc->vchan.lock, flags);
 
 	return sr;
 }
@@ -273,14 +265,11 @@  static size_t hsu_dma_active_desc_size(struct hsu_dma_chan *hsuc)
 	struct hsu_dma_desc *desc = hsuc->desc;
 	size_t bytes = hsu_dma_desc_size(desc);
 	int i;
-	unsigned long flags;
 
-	spin_lock_irqsave(&hsuc->lock, flags);
 	i = desc->active % HSU_DMA_CHAN_NR_DESC;
 	do {
 		bytes += hsu_chan_readl(hsuc, HSU_CH_DxTSR(i));
 	} while (--i >= 0);
-	spin_unlock_irqrestore(&hsuc->lock, flags);
 
 	return bytes;
 }
@@ -327,24 +316,6 @@  static int hsu_dma_slave_config(struct dma_chan *chan,
 	return 0;
 }
 
-static void hsu_dma_chan_deactivate(struct hsu_dma_chan *hsuc)
-{
-	unsigned long flags;
-
-	spin_lock_irqsave(&hsuc->lock, flags);
-	hsu_chan_disable(hsuc);
-	spin_unlock_irqrestore(&hsuc->lock, flags);
-}
-
-static void hsu_dma_chan_activate(struct hsu_dma_chan *hsuc)
-{
-	unsigned long flags;
-
-	spin_lock_irqsave(&hsuc->lock, flags);
-	hsu_chan_enable(hsuc);
-	spin_unlock_irqrestore(&hsuc->lock, flags);
-}
-
 static int hsu_dma_pause(struct dma_chan *chan)
 {
 	struct hsu_dma_chan *hsuc = to_hsu_dma_chan(chan);
@@ -352,7 +323,7 @@  static int hsu_dma_pause(struct dma_chan *chan)
 
 	spin_lock_irqsave(&hsuc->vchan.lock, flags);
 	if (hsuc->desc && hsuc->desc->status == DMA_IN_PROGRESS) {
-		hsu_dma_chan_deactivate(hsuc);
+		hsu_chan_disable(hsuc);
 		hsuc->desc->status = DMA_PAUSED;
 	}
 	spin_unlock_irqrestore(&hsuc->vchan.lock, flags);
@@ -368,7 +339,7 @@  static int hsu_dma_resume(struct dma_chan *chan)
 	spin_lock_irqsave(&hsuc->vchan.lock, flags);
 	if (hsuc->desc && hsuc->desc->status == DMA_PAUSED) {
 		hsuc->desc->status = DMA_IN_PROGRESS;
-		hsu_dma_chan_activate(hsuc);
+		hsu_chan_enable(hsuc);
 	}
 	spin_unlock_irqrestore(&hsuc->vchan.lock, flags);
 
@@ -441,8 +412,6 @@  int hsu_dma_probe(struct hsu_dma_chip *chip)
 
 		hsuc->direction = (i & 0x1) ? DMA_DEV_TO_MEM : DMA_MEM_TO_DEV;
 		hsuc->reg = addr + i * HSU_DMA_CHAN_LENGTH;
-
-		spin_lock_init(&hsuc->lock);
 	}
 
 	dma_cap_set(DMA_SLAVE, hsu->dma.cap_mask);
diff --git a/drivers/dma/hsu/hsu.h b/drivers/dma/hsu/hsu.h
index 0275233..eeb9fff 100644
--- a/drivers/dma/hsu/hsu.h
+++ b/drivers/dma/hsu/hsu.h
@@ -78,7 +78,6 @@  struct hsu_dma_chan {
 	struct virt_dma_chan vchan;
 
 	void __iomem *reg;
-	spinlock_t lock;
 
 	/* hardware configuration */
 	enum dma_transfer_direction direction;