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@xxxxxx> --- arch/arm/boot/dts/am437x-gp-evm.dts | 1 + arch/arm/boot/dts/am43x-epos-evm.dts | 1 + 2 files changed, 2 insertions(+) diff --git a/arch/arm/boot/dts/am437x-gp-evm.dts b/arch/arm/boot/dts/am437x-gp-evm.dts index 29a538e..a0a4ed0 100644 --- a/arch/arm/boot/dts/am437x-gp-evm.dts +++ b/arch/arm/boot/dts/am437x-gp-evm.dts @@ -842,6 +842,7 @@ interrupts = <0 IRQ_TYPE_NONE>, /* fifoevent */ <1 IRQ_TYPE_NONE>; /* termcount */ rb-gpios = <&gpmc 0 GPIO_ACTIVE_HIGH>; /* gpmc_wait0 */ + ti,nand-xfer-type = "prefetch-dma"; ti,nand-ecc-opt = "bch16"; ti,elm-id = <&elm>; nand-bus-width = <8>; diff --git a/arch/arm/boot/dts/am43x-epos-evm.dts b/arch/arm/boot/dts/am43x-epos-evm.dts index 54f40f3..9d276af 100644 --- a/arch/arm/boot/dts/am43x-epos-evm.dts +++ b/arch/arm/boot/dts/am43x-epos-evm.dts @@ -564,6 +564,7 @@ interrupts = <0 IRQ_TYPE_NONE>, /* fifoevent */ <1 IRQ_TYPE_NONE>; /* termcount */ rb-gpios = <&gpmc 0 GPIO_ACTIVE_HIGH>; /* gpmc_wait0 */ + ti,nand-xfer-type = "prefetch-dma"; ti,nand-ecc-opt = "bch16"; ti,elm-id = <&elm>; nand-bus-width = <8>; -- 2.10.0 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
