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[PATCH 21/21] dmaengine: edma: Simplify and optimize ccerr interrupt handler

From Peter Ujfalusi <peter.ujfalusi@ti.com>
Newsgroups linux.kernel
Subject [PATCH 21/21] dmaengine: edma: Simplify and optimize ccerr interrupt handler
Date 2015-09-10 10:50 +0200
Message-ID <q75Im-4L3-39@gated-at.bofh.it> (permalink)
References <q75yF-4zn-13@gated-at.bofh.it>
Organization linux.* mail to news gateway

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No need to run through the bits in QEMR and CCERR events since they will
not trigger any action, so just clearing the errors there is fine.
In case of the missed event the loop can be optimized so we spend less time
to handle the event.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
---
 drivers/dma/edma.c | 64 ++++++++++++++++++++----------------------------------
 1 file changed, 23 insertions(+), 41 deletions(-)

diff --git a/drivers/dma/edma.c b/drivers/dma/edma.c
index f1e898525ae6..81302daf687c 100644
--- a/drivers/dma/edma.c
+++ b/drivers/dma/edma.c
@@ -1625,6 +1625,7 @@ static irqreturn_t dma_ccerr_handler(int irq, void *data)
 	int i;
 	int ctlr;
 	unsigned int cnt = 0;
+	unsigned int val;
 
 	ctlr = ecc->id;
 	if (ctlr < 0)
@@ -1637,54 +1638,35 @@ static irqreturn_t dma_ccerr_handler(int irq, void *data)
 
 	while (1) {
 		int j = -1;
-		if (edma_read_array(ecc, EDMA_EMR, 0))
+		if ((val = edma_read_array(ecc, EDMA_EMR, 0)))
 			j = 0;
-		else if (edma_read_array(ecc, EDMA_EMR, 1))
+		else if ((val = edma_read_array(ecc, EDMA_EMR, 1)))
 			j = 1;
 		if (j >= 0) {
-			dev_dbg(ecc->dev, "EMR%d %08x\n", j,
-				edma_read_array(ecc, EDMA_EMR, j));
-			for (i = 0; i < 32; i++) {
+			unsigned long emr = val;
+
+			dev_dbg(ecc->dev, "EMR%d 0x%08x\n", j, val);
+			for (i = find_next_bit(&emr, 32, 0); i < 32;
+			     i = find_next_bit(&emr, 32, i + 1)) {
 				int k = (j << 5) + i;
-				if (edma_read_array(ecc, EDMA_EMR, j) &
-							BIT(i)) {
-					/* Clear the corresponding EMR bits */
-					edma_write_array(ecc, EDMA_EMCR, j,
+				/* Clear the corresponding EMR bits */
+				edma_write_array(ecc, EDMA_EMCR, j, BIT(i));
+				/* Clear any SER */
+				edma_shadow0_write_array(ecc, SH_SECR, j,
 							 BIT(i));
-					/* Clear any SER */
-					edma_shadow0_write_array(ecc, SH_SECR,
-								j, BIT(i));
-					edma_error_handler(&ecc->slave_chans[k]);
-				}
-			}
-		} else if (edma_read(ecc, EDMA_QEMR)) {
-			dev_dbg(ecc->dev, "QEMR %02x\n",
-				edma_read(ecc, EDMA_QEMR));
-			for (i = 0; i < 8; i++) {
-				if (edma_read(ecc, EDMA_QEMR) & BIT(i)) {
-					/* Clear the corresponding IPR bits */
-					edma_write(ecc, EDMA_QEMCR, BIT(i));
-					edma_shadow0_write(ecc, SH_QSECR,
-							   BIT(i));
-
-					/* NOTE:  not reported!! */
-				}
-			}
-		} else if (edma_read(ecc, EDMA_CCERR)) {
-			dev_dbg(ecc->dev, "CCERR %08x\n",
-				edma_read(ecc, EDMA_CCERR));
-			/* FIXME:  CCERR.BIT(16) ignored!  much better
-			 * to just write CCERRCLR with CCERR value...
-			 */
-			for (i = 0; i < 8; i++) {
-				if (edma_read(ecc, EDMA_CCERR) & BIT(i)) {
-					/* Clear the corresponding IPR bits */
-					edma_write(ecc, EDMA_CCERRCLR, BIT(i));
-
-					/* NOTE:  not reported!! */
-				}
+				edma_error_handler(&ecc->slave_chans[k]);
 			}
+		} else if ((val = edma_read(ecc, EDMA_QEMR))) {
+			dev_dbg(ecc->dev, "QEMR 0x%02x\n", val);
+			/* Not reported, just clear the interrupt reason. */
+			edma_write(ecc, EDMA_QEMCR, val);
+			edma_shadow0_write(ecc, SH_QSECR, val);
+		} else if ((val = edma_read(ecc, EDMA_CCERR))) {
+			dev_warn(ecc->dev, "CCERR 0x%08x\n", val);
+			/* Not reported, just clear the interrupt reason. */
+			edma_write(ecc, EDMA_CCERRCLR, val);
 		}
+
 		if (!edma_error_pending(ecc))
 			break;
 		cnt++;
-- 
2.5.1

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Thread

[PATCH 00/21] dmaengine/ARM: Merge the edma drivers into one Peter Ujfalusi <peter.ujfalusi@ti.com> - 2015-09-10 10:40 +0200
  Re: [PATCH 00/21] dmaengine/ARM: Merge the edma drivers into one Arnd Bergmann <arnd@arndb.de> - 2015-09-10 10:50 +0200
  [PATCH 05/21] ARM/dmaengine: edma: Move of_dma_controller_register to the dmaengine driver Peter Ujfalusi <peter.ujfalusi@ti.com> - 2015-09-10 10:50 +0200
  [PATCH 13/21] dmaengine: edma: Use devm_kcalloc when possible Peter Ujfalusi <peter.ujfalusi@ti.com> - 2015-09-10 10:50 +0200
  Re: [PATCH 08/21] ARM/dmaengine: edma: Remove limitation on the number of eDMA controllers Arnd Bergmann <arnd@arndb.de> - 2015-09-10 10:50 +0200
    Re: [PATCH 08/21] ARM/dmaengine: edma: Remove limitation on the  number of eDMA controllers Peter Ujfalusi <peter.ujfalusi@ti.com> - 2015-09-10 11:20 +0200
  [PATCH 02/21] ARM: common: edma: Remove unused functions Peter Ujfalusi <peter.ujfalusi@ti.com> - 2015-09-10 10:50 +0200
  [PATCH 14/21] dmaengine: edma: Cleanup regarding the use of dev around the code Peter Ujfalusi <peter.ujfalusi@ti.com> - 2015-09-10 10:50 +0200
  [PATCH 03/21] dmaengine: edma: Simplify and optimize the edma_execute path Peter Ujfalusi <peter.ujfalusi@ti.com> - 2015-09-10 10:50 +0200
  [PATCH 04/21] ARM: davinci/common: Convert edma driver to handle one eDMA instance per driver Peter Ujfalusi <peter.ujfalusi@ti.com> - 2015-09-10 10:50 +0200
  [PATCH 08/21] ARM/dmaengine: edma: Remove limitation on the number of eDMA controllers Peter Ujfalusi <peter.ujfalusi@ti.com> - 2015-09-10 10:50 +0200
  [PATCH 21/21] dmaengine: edma: Simplify and optimize ccerr interrupt handler Peter Ujfalusi <peter.ujfalusi@ti.com> - 2015-09-10 10:50 +0200
  [PATCH 16/21] dmaengine: edma: Use the edma_write_slot instead open coded memcpy_toio Peter Ujfalusi <peter.ujfalusi@ti.com> - 2015-09-10 10:50 +0200
  [PATCH 19/21] dmaengine: edma: Simplify the interrupt handling Peter Ujfalusi <peter.ujfalusi@ti.com> - 2015-09-10 10:50 +0200
  [PATCH 18/21] dmaengine: edma: Consolidate the comments for functions Peter Ujfalusi <peter.ujfalusi@ti.com> - 2015-09-10 10:50 +0200
  [PATCH 12/21] dmaengine: edma: Parameter alignment and long line fixes Peter Ujfalusi <peter.ujfalusi@ti.com> - 2015-09-10 10:50 +0200
  [PATCH 07/21] ARM/dmaengine: edma: Public API to use private struct pointer Peter Ujfalusi <peter.ujfalusi@ti.com> - 2015-09-10 10:50 +0200
  [PATCH 15/21] dmaengine: edma: Use dev_dbg instead pr_debug Peter Ujfalusi <peter.ujfalusi@ti.com> - 2015-09-10 10:50 +0200
  [PATCH 20/21] dmaengine: edma: Move the pending error check into helper function Peter Ujfalusi <peter.ujfalusi@ti.com> - 2015-09-10 10:50 +0200

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