Re: [PATCH u-boot-marvell 1/2] arm: mvebu: spl: Add option to reset the board on DDR training failure

On Thursday 17 February 2022 12:42:58 Stefan Roese wrote:

On 2/17/22 12:37, Pali Rohár wrote:

...

On Thursday 17 February 2022 01:08:48 Marek Behún wrote:

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From: Marek Behún marek.behun@nic.cz

Some boards may occacionally fail DDR training. Currently we hang() in this case. Add an option that makes the board do an immediate reset in such a case, so that a new training is tried as soon as possible, instead of hanging and possibly waiting for watchdog to reset the board.

Signed-off-by: Marek Behún marek.behun@nic.cz Reviewed-by: Stefan Roese sr@denx.de

---

arch/arm/mach-mvebu/Kconfig | 9 +++++++++ arch/arm/mach-mvebu/spl.c | 6 +++++- 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/arch/arm/mach-mvebu/Kconfig b/arch/arm/mach-mvebu/Kconfig index d23cc0c760..ed957be6e1 100644 --- a/arch/arm/mach-mvebu/Kconfig +++ b/arch/arm/mach-mvebu/Kconfig @@ -213,6 +213,15 @@ config DDR_LOG_LEVEL At level 3, rovides the windows margin of each DQ as a results of DQS centeralization. +config DDR_RESET_ON_TRAINING_FAILURE

• bool "Reset the board on DDR training failure instead of hanging"
• depends on ARMADA_38X || ARMADA_XP
• help

•  If DDR training fails in SPL, reset the board instead of hanging.
  

•  Some boards are known to fail DDR training occasionally and an
  

•  immediate reset may be preferable to waiting until the board is
  

•  reset by watchdog (if there even is one).
  

• config SYS_BOARD default "clearfog" if TARGET_CLEARFOG default "helios4" if TARGET_HELIOS4

diff --git a/arch/arm/mach-mvebu/spl.c b/arch/arm/mach-mvebu/spl.c index 273ecb8bd6..d3c3bdc74d 100644 --- a/arch/arm/mach-mvebu/spl.c +++ b/arch/arm/mach-mvebu/spl.c @@ -4,6 +4,7 @@ */ #include <common.h> +#include <cpu_func.h> #include <dm.h> #include <fdtdec.h> #include <hang.h> @@ -330,7 +331,10 @@ void board_init_f(ulong dummy) ret = ddr3_init(); if (ret) { printf("ddr3_init() failed: %d\n", ret);

• hang();
  

• if (IS_ENABLED(CONFIG_DDR_RESET_ON_TRAINING_FAILURE))
  

• 	reset_cpu();
  

You should not call reset_cpu() from SPL loaded via UART. This will confuse x-modem software. Either return failure to BootROM or hang() like it was before.

I see that this might confuse the kwboot / x-modem use-case. But AFAIU, this is more targeted to the normal use-case, that the board boots from SPI NOR (etc).

But kwb image is universal for both UART and SPI booting. So it target both use cases.

And here, a complete re-start could be helpful to at least get the board up and running after a few retries.

Of course, for SPI boot source it is required.

Or am I missing something?

Just reset_cpu() call should be skipped when SPL is loaded via UART.

Thanks, Stefan