diff mbox

[2/2,v2] dma: ipu_idmac: do not lose valid received data in the irq handler

Message ID 1296476549-10421-1-git-send-email-agust@denx.de (mailing list archive)
State Not Applicable
Headers show

Commit Message

Anatolij Gustschin Jan. 31, 2011, 12:22 p.m. UTC
None
diff mbox

Patch

diff --git a/drivers/dma/ipu/ipu_idmac.c b/drivers/dma/ipu/ipu_idmac.c
index cb26ee9..c1a125e 100644
--- a/drivers/dma/ipu/ipu_idmac.c
+++ b/drivers/dma/ipu/ipu_idmac.c
@@ -1145,29 +1145,6 @@  static int ipu_disable_channel(struct idmac *idmac, struct idmac_channel *ichan,
 	reg = idmac_read_icreg(ipu, IDMAC_CHA_EN);
 	idmac_write_icreg(ipu, reg & ~chan_mask, IDMAC_CHA_EN);
 
-	/*
-	 * Problem (observed with channel DMAIC_7): after enabling the channel
-	 * and initialising buffers, there comes an interrupt with current still
-	 * pointing at buffer 0, whereas it should use buffer 0 first and only
-	 * generate an interrupt when it is done, then current should already
-	 * point to buffer 1. This spurious interrupt also comes on channel
-	 * DMASDC_0. With DMAIC_7 normally, is we just leave the ISR after the
-	 * first interrupt, there comes the second with current correctly
-	 * pointing to buffer 1 this time. But sometimes this second interrupt
-	 * doesn't come and the channel hangs. Clearing BUFx_RDY when disabling
-	 * the channel seems to prevent the channel from hanging, but it doesn't
-	 * prevent the spurious interrupt. This might also be unsafe. Think
-	 * about the IDMAC controller trying to switch to a buffer, when we
-	 * clear the ready bit, and re-enable it a moment later.
-	 */
-	reg = idmac_read_ipureg(ipu, IPU_CHA_BUF0_RDY);
-	idmac_write_ipureg(ipu, 0, IPU_CHA_BUF0_RDY);
-	idmac_write_ipureg(ipu, reg & ~(1UL << channel), IPU_CHA_BUF0_RDY);
-
-	reg = idmac_read_ipureg(ipu, IPU_CHA_BUF1_RDY);
-	idmac_write_ipureg(ipu, 0, IPU_CHA_BUF1_RDY);
-	idmac_write_ipureg(ipu, reg & ~(1UL << channel), IPU_CHA_BUF1_RDY);
-
 	spin_unlock_irqrestore(&ipu->lock, flags);
 
 	return 0;
@@ -1246,33 +1223,6 @@  static irqreturn_t idmac_interrupt(int irq, void *dev_id)
 
 	/* Other interrupts do not interfere with this channel */
 	spin_lock(&ichan->lock);
-	if (unlikely(chan_id != IDMAC_SDC_0 && chan_id != IDMAC_SDC_1 &&
-		     ((curbuf >> chan_id) & 1) == ichan->active_buffer &&
-		     !list_is_last(ichan->queue.next, &ichan->queue))) {
-		int i = 100;
-
-		/* This doesn't help. See comment in ipu_disable_channel() */
-		while (--i) {
-			curbuf = idmac_read_ipureg(&ipu_data, IPU_CHA_CUR_BUF);
-			if (((curbuf >> chan_id) & 1) != ichan->active_buffer)
-				break;
-			cpu_relax();
-		}
-
-		if (!i) {
-			spin_unlock(&ichan->lock);
-			dev_dbg(dev,
-				"IRQ on active buffer on channel %x, active "
-				"%d, ready %x, %x, current %x!\n", chan_id,
-				ichan->active_buffer, ready0, ready1, curbuf);
-			return IRQ_NONE;
-		} else
-			dev_dbg(dev,
-				"Buffer deactivated on channel %x, active "
-				"%d, ready %x, %x, current %x, rest %d!\n", chan_id,
-				ichan->active_buffer, ready0, ready1, curbuf, i);
-	}
-
 	if (unlikely((ichan->active_buffer && (ready1 >> chan_id) & 1) ||
 		     (!ichan->active_buffer && (ready0 >> chan_id) & 1)
 		     )) {