Revert "dmaengine: ep93xx: Don't drain the transfers in terminate_all()"

This reverts commit 81402e40.
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>

drivers/dma/ep93xx_dma.c

@@ -201,7 +201,6 @@ struct ep93xx_dma_engine {
 	struct dma_device	dma_dev;
 	bool			m2m;
 	int			(*hw_setup)(struct ep93xx_dma_chan *);
-	void			(*hw_synchronize)(struct ep93xx_dma_chan *);
 	void			(*hw_shutdown)(struct ep93xx_dma_chan *);
 	void			(*hw_submit)(struct ep93xx_dma_chan *);
 	int			(*hw_interrupt)(struct ep93xx_dma_chan *);
@@ -336,27 +335,21 @@ static inline u32 m2p_channel_state(struct ep93xx_dma_chan *edmac)
 	return (readl(edmac->regs + M2P_STATUS) >> 4) & 0x3;
 }
 
-static void m2p_hw_synchronize(struct ep93xx_dma_chan *edmac)
+static void m2p_hw_shutdown(struct ep93xx_dma_chan *edmac)
 {
-	unsigned long flags;
 	u32 control;
 
-	spin_lock_irqsave(&edmac->lock, flags);
 	control = readl(edmac->regs + M2P_CONTROL);
 	control &= ~(M2P_CONTROL_STALLINT | M2P_CONTROL_NFBINT);
 	m2p_set_control(edmac, control);
-	spin_unlock_irqrestore(&edmac->lock, flags);
 
 	while (m2p_channel_state(edmac) >= M2P_STATE_ON)
-		schedule();
-}
+		cpu_relax();
 
-static void m2p_hw_shutdown(struct ep93xx_dma_chan *edmac)
-{
 	m2p_set_control(edmac, 0);
 
-	while (m2p_channel_state(edmac) != M2P_STATE_IDLE)
-		dev_warn(chan2dev(edmac), "M2P: Not yet IDLE\n");
+	while (m2p_channel_state(edmac) == M2P_STATE_STALL)
+		cpu_relax();
 }
 
 static void m2p_fill_desc(struct ep93xx_dma_chan *edmac)
@@ -1171,26 +1164,6 @@ ep93xx_dma_prep_dma_cyclic(struct dma_chan *chan, dma_addr_t dma_addr,
 	return NULL;
 }
 
-/**
- * ep93xx_dma_synchronize - Synchronizes the termination of transfers to the
- * current context.
- * @chan: channel
- *
- * Synchronizes the DMA channel termination to the current context. When this
- * function returns it is guaranteed that all transfers for previously issued
- * descriptors have stopped and and it is safe to free the memory associated
- * with them. Furthermore it is guaranteed that all complete callback functions
- * for a previously submitted descriptor have finished running and it is safe to
- * free resources accessed from within the complete callbacks.
- */
-static void ep93xx_dma_synchronize(struct dma_chan *chan)
-{
-	struct ep93xx_dma_chan *edmac = to_ep93xx_dma_chan(chan);
-
-	if (edmac->edma->hw_synchronize)
-		edmac->edma->hw_synchronize(edmac);
-}
-
 /**
  * ep93xx_dma_terminate_all - terminate all transactions
  * @chan: channel
@@ -1354,7 +1327,6 @@ static int __init ep93xx_dma_probe(struct platform_device *pdev)
 	dma_dev->device_prep_slave_sg = ep93xx_dma_prep_slave_sg;
 	dma_dev->device_prep_dma_cyclic = ep93xx_dma_prep_dma_cyclic;
 	dma_dev->device_config = ep93xx_dma_slave_config;
-	dma_dev->device_synchronize = ep93xx_dma_synchronize;
 	dma_dev->device_terminate_all = ep93xx_dma_terminate_all;
 	dma_dev->device_issue_pending = ep93xx_dma_issue_pending;
 	dma_dev->device_tx_status = ep93xx_dma_tx_status;
@@ -1372,7 +1344,6 @@ static int __init ep93xx_dma_probe(struct platform_device *pdev)
 	} else {
 		dma_cap_set(DMA_PRIVATE, dma_dev->cap_mask);
 
-		edma->hw_synchronize = m2p_hw_synchronize;
 		edma->hw_setup = m2p_hw_setup;
 		edma->hw_shutdown = m2p_hw_shutdown;
 		edma->hw_submit = m2p_hw_submit;