[v3,9/9] fsldma: make halt behave nicely on all supported controllers

Submitted by Ira Snyder on March 3, 2011, 5:55 p.m.

Details

Message ID 1299174901-16762-10-git-send-email-iws@ovro.caltech.edu
State Accepted, archived
Delegated to: Kumar Gala
Headers show

Commit Message

Ira Snyder March 3, 2011, 5:55 p.m.
The original dma_halt() function set the CA (channel abort) bit on both
the 83xx and 85xx controllers. This is incorrect on the 83xx, where this
bit means TEM (transfer error mask) instead. The 83xx doesn't support
channel abort, so we only do this operation on 85xx.

Signed-off-by: Ira W. Snyder <iws@ovro.caltech.edu>
---
 drivers/dma/fsldma.c |   19 ++++++++++++++++---
 1 files changed, 16 insertions(+), 3 deletions(-)

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diff --git a/drivers/dma/fsldma.c b/drivers/dma/fsldma.c
index d300de4..8670a50 100644
--- a/drivers/dma/fsldma.c
+++ b/drivers/dma/fsldma.c
@@ -221,13 +221,26 @@  static void dma_halt(struct fsldma_chan *chan)
 	u32 mode;
 	int i;
 
+	/* read the mode register */
 	mode = DMA_IN(chan, &chan->regs->mr, 32);
-	mode |= FSL_DMA_MR_CA;
-	DMA_OUT(chan, &chan->regs->mr, mode, 32);
 
-	mode &= ~(FSL_DMA_MR_CS | FSL_DMA_MR_EMS_EN | FSL_DMA_MR_CA);
+	/*
+	 * The 85xx controller supports channel abort, which will stop
+	 * the current transfer. On 83xx, this bit is the transfer error
+	 * mask bit, which should not be changed.
+	 */
+	if ((chan->feature & FSL_DMA_IP_MASK) == FSL_DMA_IP_85XX) {
+		mode |= FSL_DMA_MR_CA;
+		DMA_OUT(chan, &chan->regs->mr, mode, 32);
+
+		mode &= ~FSL_DMA_MR_CA;
+	}
+
+	/* stop the DMA controller */
+	mode &= ~(FSL_DMA_MR_CS | FSL_DMA_MR_EMS_EN);
 	DMA_OUT(chan, &chan->regs->mr, mode, 32);
 
+	/* wait for the DMA controller to become idle */
 	for (i = 0; i < 100; i++) {
 		if (dma_is_idle(chan))
 			return;