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[3/3] ARM: dts: dra7xx: Enable NAND dma prefetch by default

Message ID 20170726021552.19880-4-fcooper@ti.com (mailing list archive)
State New, archived
Headers show

Commit Message

Franklin Cooper July 26, 2017, 2:15 a.m. UTC 
Currently the default method of prefetch polled shows the highest
possible read and write speed when minimal non NAND background
activity is being done. But it is also very CPU intensive to reach
these high speeds (CPU load of 99% via mtd performance tests). While
DMA prefetch only uses 50% of the CPU to achieve around 23% less in
top read and write performance.

However, as the non NAND CPU load increases the read and write
performance takes a large hit when using polled prefetch. Therefore,
prefetch dma mode ends up outperforming prefetch polled in general
"system level" test. So switch to using dma prefetch by default since
it is likely what most users would prefer.

Signed-off-by: Franklin S Cooper Jr <fcooper@ti.com>
---
 arch/arm/boot/dts/dra7-evm.dts          | 1 +
 arch/arm/boot/dts/dra72-evm-common.dtsi | 1 +
 2 files changed, 2 insertions(+)
diff mbox

Patch

diff --git a/arch/arm/boot/dts/dra7-evm.dts b/arch/arm/boot/dts/dra7-evm.dts
index f47fc4d..7d55af9 100644
--- a/arch/arm/boot/dts/dra7-evm.dts
+++ b/arch/arm/boot/dts/dra7-evm.dts
@@ -556,6 +556,7 @@ 
 		interrupts = <0 IRQ_TYPE_NONE>, /* fifoevent */
 			     <1 IRQ_TYPE_NONE>; /* termcount */
 		rb-gpios = <&gpmc 0 GPIO_ACTIVE_HIGH>; /* gpmc_wait0 pin */
+		ti,nand-xfer-type = "prefetch-dma";
 		ti,nand-ecc-opt = "bch8";
 		ti,elm-id = <&elm>;
 		nand-bus-width = <16>;
diff --git a/arch/arm/boot/dts/dra72-evm-common.dtsi b/arch/arm/boot/dts/dra72-evm-common.dtsi
index 8578054..1830483 100644
--- a/arch/arm/boot/dts/dra72-evm-common.dtsi
+++ b/arch/arm/boot/dts/dra72-evm-common.dtsi
@@ -311,6 +311,7 @@ 
 		interrupts = <0 IRQ_TYPE_NONE>, /* fifoevent */
 			     <1 IRQ_TYPE_NONE>;	/* termcount */
 		rb-gpios = <&gpmc 0 GPIO_ACTIVE_HIGH>; /* gpmc_wait0 pin */
+		ti,nand-xfer-type = "prefetch-dma";
 		ti,nand-ecc-opt = "bch8";
 		ti,elm-id = <&elm>;
 		nand-bus-width = <16>;