On Wed, Jul 25, 2018 at 10:16:28AM +0200, H. Nikolaus Schaller wrote:

Hi,

quoted

Am 25.07.2018 um 10:10 schrieb Ladislav Michl [off-list ref]:

On Wed, Jul 25, 2018 at 08:58:42AM +0200, H. Nikolaus Schaller wrote:

quoted

to better match omap3-beagle.dts (which was the basis
of designing the GTA04).

Signed-off-by: H. Nikolaus Schaller <redacted>
---
arch/arm/boot/dts/omap3-gta04.dtsi | 14 +++++++-------
1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/arch/arm/boot/dts/omap3-gta04.dtsi b/arch/arm/boot/dts/omap3-gta04.dtsi
index 03fe404cbf56..9568e0c4d4bf 100644
--- a/arch/arm/boot/dts/omap3-gta04.dtsi
+++ b/arch/arm/boot/dts/omap3-gta04.dtsi

@@ -616,27 +616,27 @@

		interrupt-parent = <&gpmc>;
		interrupts = <0 IRQ_TYPE_NONE>, /* fifoevent */
			     <1 IRQ_TYPE_NONE>;	/* termcount */
+		ti,nand-ecc-opt = "ham1";
+		rb-gpios = <&gpmc 0 GPIO_ACTIVE_HIGH>; /* gpmc_wait0 */
		nand-bus-width = <16>;
-		ti,nand-ecc-opt = "bch8";

You are using weeker ECC scheme just to be compatible with another machine?

No not another machine. The GTA04 uses the same SoC and NAND chip as the BeagleBoard,
so you can imagine GTA04 being a BeagleBoard + a lot of other things.

The key reason is to change the ecc scheme is to be compatible with the U-Boot used.

BootROM can only handle ham1 for the MLO. And there is no nand-ecc-opt
for each partition. So we either can't mix ECC schemes if we want to be able
to read/write MLO as the first partition from kernel.

quoted

So now you cannot boot already deployed filesystem...

No. We always used ham1 and bch8 wasn't working at all here. Therefore nobody
did use upstream kernel for NAND yet...

quoted

Also is it enough for
NAND chip used?

Well, the chip is recommended to use bch8 but BootROM imposes above mentioned limits.

Then common way to handle such a situation is to use 1bit hamming for MLO and BCH8 for
the rest. You will end with corrupted filesystem with ham1 which I'd consider very
unfortunate.

(I know there were endless discussions how to handle this situation. It is already
solved in U-Boot and for updating MLO from Linux I'm using writeloader tool)

	ladis

BR,
Nikolaus

quoted

	ladis

quoted

+		#address-cells = <1>;
+		#size-cells = <1>;

-		gpmc,sync-clk-ps = <0>;
+		gpmc,device-width = <2>;
		gpmc,cs-on-ns = <0>;
		gpmc,cs-rd-off-ns = <44>;
		gpmc,cs-wr-off-ns = <44>;
		gpmc,adv-on-ns = <6>;
		gpmc,adv-rd-off-ns = <34>;
		gpmc,adv-wr-off-ns = <44>;
-		gpmc,we-off-ns = <40>;
		gpmc,oe-off-ns = <54>;
+		gpmc,we-off-ns = <40>;
		gpmc,access-ns = <64>;
		gpmc,rd-cycle-ns = <82>;
		gpmc,wr-cycle-ns = <82>;
		gpmc,wr-access-ns = <40>;
		gpmc,wr-data-mux-bus-ns = <0>;
-		gpmc,device-width = <2>;
-
-		#address-cells = <1>;
-		#size-cells = <1>;
+		gpmc,sync-clk-ps = <0>;

		x-loader@0 {
			label = "X-Loader";
-- 
2.12.2

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