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From: Viresh Kumar <viresh.kumar@st.com>
To: <linus.walleij@linaro.org>, <vinod.koul@intel.com>,
	<dan.j.williams@intel.com>
Cc: <linux-arm-kernel@lists.infradead.org>, <armando.visconti@st.com>,
	<shiraz.hashim@st.com>, <vipin.kumar@st.com>,
	<rajeev-dlh.kumar@st.com>, <deepak.sikri@st.com>,
	<vipulkumar.samar@st.com>, <amit.virdi@st.com>,
	<viresh.kumar@st.com>, <pratyush.anand@st.com>,
	<bhupesh.sharma@st.com>, <viresh.linux@gmail.com>,
	<linux-kernel@vger.kernel.org>, <linux@arm.linux.org.uk>,
	<alim.akhtar@gmail.com>
Subject: [PATCH V3 16/20] dmaengine/amba-pl08x: Choose peripheral bus as master bus
Date: Fri, 5 Aug 2011 15:32:41 +0530	[thread overview]
Message-ID: <cff6b2f1abd15651ecb9dfeafd9a89d2dae05312.1312538034.git.viresh.kumar@st.com> (raw)
In-Reply-To: <cover.1312538034.git.viresh.kumar@st.com>

When we have DMA transfers between peripheral and memory, then we shouldn't
reduce width of peripheral at all, as that may be a strict requirement. But we
can always reduce width of memory access, with some compromise in performance.
Thus, we must select peripheral as master and not memory.

Also this rearranges code to make it shorter.

Signed-off-by: Viresh Kumar <viresh.kumar@st.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
---
 drivers/dma/amba-pl08x.c |   22 ++++++----------------
 1 files changed, 6 insertions(+), 16 deletions(-)

diff --git a/drivers/dma/amba-pl08x.c b/drivers/dma/amba-pl08x.c
index 4bcf603..f70aa57 100644
--- a/drivers/dma/amba-pl08x.c
+++ b/drivers/dma/amba-pl08x.c
@@ -499,34 +499,24 @@ struct pl08x_lli_build_data {
  * byte data), slave is still not aligned, then its width will be reduced to
  * BYTE.
  * - prefers the destination bus if both available
- * - if fixed address on one bus the other will be chosen
+ * - prefers bus with fixed address (i.e. peripheral)
  */
 static void pl08x_choose_master_bus(struct pl08x_lli_build_data *bd,
 	struct pl08x_bus_data **mbus, struct pl08x_bus_data **sbus, u32 cctl)
 {
 	if (!(cctl & PL080_CONTROL_DST_INCR)) {
-		*mbus = &bd->srcbus;
-		*sbus = &bd->dstbus;
-	} else if (!(cctl & PL080_CONTROL_SRC_INCR)) {
 		*mbus = &bd->dstbus;
 		*sbus = &bd->srcbus;
+	} else if (!(cctl & PL080_CONTROL_SRC_INCR)) {
+		*mbus = &bd->srcbus;
+		*sbus = &bd->dstbus;
 	} else {
-		if (bd->dstbus.buswidth == 4) {
-			*mbus = &bd->dstbus;
-			*sbus = &bd->srcbus;
-		} else if (bd->srcbus.buswidth == 4) {
-			*mbus = &bd->srcbus;
-			*sbus = &bd->dstbus;
-		} else if (bd->dstbus.buswidth == 2) {
+		if (bd->dstbus.buswidth >= bd->srcbus.buswidth) {
 			*mbus = &bd->dstbus;
 			*sbus = &bd->srcbus;
-		} else if (bd->srcbus.buswidth == 2) {
+		} else {
 			*mbus = &bd->srcbus;
 			*sbus = &bd->dstbus;
-		} else {
-			/* bd->srcbus.buswidth == 1 */
-			*mbus = &bd->dstbus;
-			*sbus = &bd->srcbus;
 		}
 	}
 }
-- 
1.7.2.2


WARNING: multiple messages have this Message-ID (diff)
From: viresh.kumar@st.com (Viresh Kumar)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH V3 16/20] dmaengine/amba-pl08x: Choose peripheral bus as master bus
Date: Fri, 5 Aug 2011 15:32:41 +0530	[thread overview]
Message-ID: <cff6b2f1abd15651ecb9dfeafd9a89d2dae05312.1312538034.git.viresh.kumar@st.com> (raw)
In-Reply-To: <cover.1312538034.git.viresh.kumar@st.com>

When we have DMA transfers between peripheral and memory, then we shouldn't
reduce width of peripheral at all, as that may be a strict requirement. But we
can always reduce width of memory access, with some compromise in performance.
Thus, we must select peripheral as master and not memory.

Also this rearranges code to make it shorter.

Signed-off-by: Viresh Kumar <viresh.kumar@st.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
---
 drivers/dma/amba-pl08x.c |   22 ++++++----------------
 1 files changed, 6 insertions(+), 16 deletions(-)

diff --git a/drivers/dma/amba-pl08x.c b/drivers/dma/amba-pl08x.c
index 4bcf603..f70aa57 100644
--- a/drivers/dma/amba-pl08x.c
+++ b/drivers/dma/amba-pl08x.c
@@ -499,34 +499,24 @@ struct pl08x_lli_build_data {
  * byte data), slave is still not aligned, then its width will be reduced to
  * BYTE.
  * - prefers the destination bus if both available
- * - if fixed address on one bus the other will be chosen
+ * - prefers bus with fixed address (i.e. peripheral)
  */
 static void pl08x_choose_master_bus(struct pl08x_lli_build_data *bd,
 	struct pl08x_bus_data **mbus, struct pl08x_bus_data **sbus, u32 cctl)
 {
 	if (!(cctl & PL080_CONTROL_DST_INCR)) {
-		*mbus = &bd->srcbus;
-		*sbus = &bd->dstbus;
-	} else if (!(cctl & PL080_CONTROL_SRC_INCR)) {
 		*mbus = &bd->dstbus;
 		*sbus = &bd->srcbus;
+	} else if (!(cctl & PL080_CONTROL_SRC_INCR)) {
+		*mbus = &bd->srcbus;
+		*sbus = &bd->dstbus;
 	} else {
-		if (bd->dstbus.buswidth == 4) {
-			*mbus = &bd->dstbus;
-			*sbus = &bd->srcbus;
-		} else if (bd->srcbus.buswidth == 4) {
-			*mbus = &bd->srcbus;
-			*sbus = &bd->dstbus;
-		} else if (bd->dstbus.buswidth == 2) {
+		if (bd->dstbus.buswidth >= bd->srcbus.buswidth) {
 			*mbus = &bd->dstbus;
 			*sbus = &bd->srcbus;
-		} else if (bd->srcbus.buswidth == 2) {
+		} else {
 			*mbus = &bd->srcbus;
 			*sbus = &bd->dstbus;
-		} else {
-			/* bd->srcbus.buswidth == 1 */
-			*mbus = &bd->dstbus;
-			*sbus = &bd->srcbus;
 		}
 	}
 }
-- 
1.7.2.2

  parent reply	other threads:[~2011-08-05 10:05 UTC|newest]

Thread overview: 46+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-08-05 10:02 [PATCH V3 00/20] dmaengine/amba-pl08x updates Viresh Kumar
2011-08-05 10:02 ` Viresh Kumar
2011-08-05 10:02 ` [PATCH V3 01/20] ARM: asm/pl080.h: Protect against multiple inclusion of header file Viresh Kumar
2011-08-05 10:02   ` Viresh Kumar
2011-08-05 10:02 ` [PATCH V3 02/20] dmaengine/amba-pl08x: Resolve formatting issues Viresh Kumar
2011-08-05 10:02   ` Viresh Kumar
2011-08-05 10:02 ` [PATCH V3 03/20] dmaengine/amba-pl08x: Rearrange inclusion of header files in ascending order Viresh Kumar
2011-08-05 10:02   ` Viresh Kumar
2011-08-05 10:02 ` [PATCH V3 04/20] dmaengine/amba-pl08x: pass (*ptr) to sizeof() instead of (struct xyz) Viresh Kumar
2011-08-05 10:02   ` Viresh Kumar
2011-08-05 10:02 ` [PATCH V3 05/20] dmaengine/amba-pl08x: Complete doc comment for struct pl08x_txd Viresh Kumar
2011-08-05 10:02   ` Viresh Kumar
2011-08-05 10:02 ` [PATCH V3 06/20] dmaengine/amba-pl08x: Remove redundant comment and rewrite original Viresh Kumar
2011-08-05 10:02   ` Viresh Kumar
2011-08-05 10:02 ` [PATCH V3 07/20] dmaengine/amba-pl08x: Changing few prints to dev_dbg from dev_info Viresh Kumar
2011-08-05 10:02   ` Viresh Kumar
2011-08-05 10:02 ` [PATCH V3 08/20] dmaengine/amba-pl08x: support runtime PM Viresh Kumar
2011-08-05 10:02   ` Viresh Kumar
2011-08-05 10:02 ` [PATCH V3 09/20] dmaengine/amba-pl08x: Simplify pl08x_ensure_on() Viresh Kumar
2011-08-05 10:02   ` Viresh Kumar
2011-08-05 10:02 ` [PATCH V3 10/20] dmaengine/amba-pl08x: No need to check "ch->signal < 0" Viresh Kumar
2011-08-05 10:02   ` Viresh Kumar
2011-08-05 10:02 ` [PATCH V3 11/20] dmaengine/amba-pl08x: Schedule tasklet in case of error interrupt Viresh Kumar
2011-08-05 10:02   ` Viresh Kumar
2011-08-05 10:02 ` [PATCH V3 12/20] dmaengine/amba-pl08x: Get rid of pl08x_pre_boundary() Viresh Kumar
2011-08-05 10:02   ` Viresh Kumar
2011-08-05 10:02 ` [PATCH V3 13/20] dmaengine/amba-pl08x: max_bytes_per_lli is TRANSFER_SIZE * src_width (not MIN(width)) Viresh Kumar
2011-08-05 10:02   ` Viresh Kumar
2011-08-05 10:02 ` [PATCH V3 14/20] dmaengine/amba-pl08x: Add prep_single_byte_llis() routine Viresh Kumar
2011-08-05 10:02   ` Viresh Kumar
2011-08-05 10:02 ` [PATCH V3 15/20] dmaengine/amba-pl08x: Align lli_len to max(src.width, dst.width) Viresh Kumar
2011-08-05 10:02   ` Viresh Kumar
2011-08-05 10:02 ` Viresh Kumar [this message]
2011-08-05 10:02   ` [PATCH V3 16/20] dmaengine/amba-pl08x: Choose peripheral bus as master bus Viresh Kumar
2011-08-05 10:02 ` [PATCH V3 17/20] dmaengine/amba-pl08x: Pass flow controller information with slave channel data Viresh Kumar
2011-08-05 10:02   ` Viresh Kumar
2011-08-05 10:02 ` [PATCH V3 18/20] dmaengine/amba-pl08x: Add support for sg len greater than one for slave transfers Viresh Kumar
2011-08-05 10:02   ` Viresh Kumar
2011-08-05 10:02 ` [PATCH V3 19/20] dmaengine/amba-pl08x: Check txd->llis_va before freeing dma_pool Viresh Kumar
2011-08-05 10:02   ` Viresh Kumar
2011-08-05 10:02 ` [PATCH V3 20/20] dmaengine/amba-pl08x: Call pl08x_free_txd() instead of calling kfree() directly Viresh Kumar
2011-08-05 10:02   ` Viresh Kumar
2011-08-23  8:17 ` [PATCH V3 00/20] dmaengine/amba-pl08x updates Linus Walleij
2011-08-23  8:17   ` Linus Walleij
2011-08-25 14:06   ` Koul, Vinod
2011-08-25 14:06     ` Koul, Vinod

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