[PATCH v3 7/7] drivers: ddr: altera: Fix Cylcone5 SPL boot loop issue

[Chee, Tien Fong]

Hi,

> -----Original Message-----
> From: Ravulapalli, Naresh Kumar <naresh.kumar.ravulapalli at altera.com>
> Sent: Tuesday, June 3, 2025 7:55 PM
> To: u-boot at lists.denx.de
> Cc: Marek Vasut <marex at denx.de>; Simon Goldschmidt
> <simon.k.r.goldschmidt at gmail.com>; Chee, Tien Fong
> <tien.fong.chee at altera.com>; Tom Rini <trini at konsulko.com>; Ravulapalli,
> Naresh Kumar <naresh.kumar.ravulapalli at altera.com>; Romli, Khairul Anuar
> <khairul.anuar.romli at altera.com>
> Subject: [PATCH v3 7/7] drivers: ddr: altera: Fix Cylcone5 SPL boot loop issue
> 
> Hardware watchdog configuration is handled correctly to resolve the SPL
> boot loop issue on Cyclone5. When hardware watchdog is enabled, it is
> reconfigured to make the defined timeout valid, else, making sure it is not
> running even if it is enabled in the preloader.
> 
> Signed-off-by: Khairul Anuar Romli <khairul.anuar.romli at altera.com>
> Signed-off-by: Naresh Kumar Ravulapalli
> <nareshkumar.ravulapalli at altera.com>
> ---
>  drivers/ddr/altera/sdram_soc32.c | 25 ++++++++++++++++++++++++-
>  1 file changed, 24 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/ddr/altera/sdram_soc32.c
> b/drivers/ddr/altera/sdram_soc32.c
> index 5cdf48d2d01..f63360f17d8 100644
> --- a/drivers/ddr/altera/sdram_soc32.c
> +++ b/drivers/ddr/altera/sdram_soc32.c
> @@ -8,6 +8,10 @@
>  #include <linux/sizes.h>
>  #include "sdram_soc32.h"
>  #include <watchdog.h>
> +#include <wait_bit.h>
> +#if !defined(CONFIG_HW_WATCHDOG)
> +#include <asm/arch/reset_manager.h>
> +#endif
> 
>  DECLARE_GLOBAL_DATA_PTR;
> 
> @@ -51,7 +55,26 @@ void sdram_init_ecc_bits(void)
>  		memset((void *)start_addr, 0, size_init);
>  		size -= size_init;
>  		start_addr += size_init;
> -		schedule();
> +
> +		if (IS_ENABLED(CONFIG_HW_WATCHDOG)) {
> +			/*
> +			 * In case the watchdog is enabled,
> +			 * make sure to (re-)configure watchdog
> +			 * so that the defined timeout is valid.
> +			 */
> +			debug("%s: %d\n", __func__, __LINE__);
> +			hw_watchdog_init();
> +		} else {
> +			/*
> +			 * If the HW watchdog is NOT enabled,
> +			 * make sure it is not running, because
> +			 * it is enabled in the preloader and
> +			 * causing boot loop if is not handled.
> +			 */
> +			debug("%s: %d\n", __func__, __LINE__);
> +			socfpga_per_reset(SOCFPGA_RESET(L4WD0), 1);
> +			socfpga_per_reset(SOCFPGA_RESET(L4WD0), 0);
> +		}

The legacy hw_watchdog_init() function is being removed, and the watchdog is either not used or has been migrated to the driver model framework.
There is a risk of watchdog timeout during boot, especially in SPL when clearing large memory region.

DM for watchdog is preferred instead of legacy API, you can check how this was implemented in Agilex.

>  	}
> 
>  	dcache_disable();
> --
> 2.35.3

BR,
Tien Fong