---

yaml
---
r: 233284
b: refs/heads/master
c: 8179661
h: refs/heads/master
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: fb526210b2b961b5d590b89fd8f45c0ca5769688
+refs/heads/master: 8179661694595eb3a4f2ff9bb0b73acbb7d2f4a9

trunk/drivers/dma/amba-pl08x.c

@@ -79,6 +79,7 @@
 #include <linux/module.h>
 #include <linux/interrupt.h>
 #include <linux/slab.h>
+#include <linux/delay.h>
 #include <linux/dmapool.h>
 #include <linux/dmaengine.h>
 #include <linux/amba/bus.h>
@@ -235,25 +236,33 @@ static void pl08x_start_txd(struct pl08x_dma_chan *plchan,
 }
 
 /*
- * Overall DMAC remains enabled always.
+ * Pause the channel by setting the HALT bit.
  *
- * Disabling individual channels could lose data.
+ * For M->P transfers, pause the DMAC first and then stop the peripheral -
+ * the FIFO can only drain if the peripheral is still requesting data.
+ * (note: this can still timeout if the DMAC FIFO never drains of data.)
  *
- * Disable the peripheral DMA after disabling the DMAC in order to allow
- * the DMAC FIFO to drain, and hence allow the channel to show inactive
+ * For P->M transfers, disable the peripheral first to stop it filling
+ * the DMAC FIFO, and then pause the DMAC.
  */
 static void pl08x_pause_phy_chan(struct pl08x_phy_chan *ch)
 {
 	u32 val;
+	int timeout;
 
 	/* Set the HALT bit and wait for the FIFO to drain */
 	val = readl(ch->base + PL080_CH_CONFIG);
 	val |= PL080_CONFIG_HALT;
 	writel(val, ch->base + PL080_CH_CONFIG);
 
 	/* Wait for channel inactive */
-	while (pl08x_phy_channel_busy(ch))
-		cpu_relax();
+	for (timeout = 1000; timeout; timeout--) {
+		if (!pl08x_phy_channel_busy(ch))
+			break;
+		udelay(1);
+	}
+	if (pl08x_phy_channel_busy(ch))
+		pr_err("pl08x: channel%u timeout waiting for pause\n", ch->id);
 }
 
 static void pl08x_resume_phy_chan(struct pl08x_phy_chan *ch)