[PATCH 1/2] arch: mach-k3: j721s2_init: Add workaround for errata i2437

[Kumar, Udit]

On 11/6/2025 12:09 PM, Neha Malcom Francis wrote:
> Add the workaround proposed for J721S2 errata i2437 (link) for SE
> clock-gating turning off too early. Without this, a hardware bug present
> in C7120 leads to C7120 CPU hanging.
>
> Link: https://www.ti.com/lit/pdf/sprz530
> Signed-off-by: Neha Malcom Francis <n-francis at ti.com>
> ---
>   arch/arm/mach-k3/j721s2/j721s2_init.c | 39 +++++++++++++++++++++++++++
>   1 file changed, 39 insertions(+)
>
> diff --git a/arch/arm/mach-k3/j721s2/j721s2_init.c b/arch/arm/mach-k3/j721s2/j721s2_init.c
> index eee3d0440ac..ecc4cbf1df8 100644
> --- a/arch/arm/mach-k3/j721s2/j721s2_init.c
> +++ b/arch/arm/mach-k3/j721s2/j721s2_init.c
> @@ -40,6 +40,15 @@
>   #define NB_THREADMAP_BIT1				BIT(1)
>   #define NB_THREADMAP_BIT2				BIT(2)
>   
> +/*
> + * RAT mapping for errata ID: i2437
> + */
> +#define RAT_ERRATA2437_BASE_REGION0		0x40f90000

Please consider RAT_ERRATA2437_BASE_REGION0 to RAT_ERRATA_2437_BASE_REGION0 for better readability
and below as well,

With this change

Reviewed-by: Udit Kumar <u-kumar1 at ti.com>

> +#define RAT_ERRATA2437_IN_ADDR			0xc0000000
> +#define RAT_ERRATA2437_OUT_ADDR_U		0x0000004d
> +#define RAT_ERRATA2437_OUT_ADDR_L		0x21000000
> +#define RAT_ERRATA2437_CTRL			0x80000010
> +
>   struct fwl_data cbass_hc_cfg0_fwls[] = {
>   	{ "PCIE0_CFG", 2577, 7 },
>   	{ "EMMC8SS0_CFG", 2579, 4 },
> @@ -346,6 +355,36 @@ void board_init_f(ulong dummy)
>   		if (ret)
>   			printf("AVS init failed: %d\n", ret);
>   	}
> +
> +	if (IS_ENABLED(CONFIG_CPU_V7R)) {
> +		/*
> +		 * Errata ID i2437: SE Clock-Gating Turning Off Too Early
> +		 *
> +		 * A hardware bug is present in the C7120 Streaming Engine top level
> +		 * clock gating logic that can lead to the C7120 CPU hanging.
> +
> +		 * Workaround: The DSP_<COREID>_DEBUG_CLKEN_OVERRIDE fields of the
> +		 * COMPUTE_CLUSTER_CFG_WRAP_0_CC_CNTRL register (where COREID is the
> +		 * name of the specific C7120 core) must be enabled before power-up
> +		 * of the C7120 core to override all clock-gating.
> +		 */
> +
> +		/* Setup RAT mapping */
> +		debug("Errata i2437: Use RAT for COMPUTE_CLUSTER_CFG_WRAP_0_CC_CNTRL register\n");
> +		*(unsigned int *)(RAT_ERRATA2437_BASE_REGION0 + 0x24) = RAT_ERRATA2437_IN_ADDR;
> +		*(unsigned int *)(RAT_ERRATA2437_BASE_REGION0 + 0x28) = RAT_ERRATA2437_OUT_ADDR_L;
> +		*(unsigned int *)(RAT_ERRATA2437_BASE_REGION0 + 0x2c) = RAT_ERRATA2437_OUT_ADDR_U;
> +		*(unsigned int *)(RAT_ERRATA2437_BASE_REGION0 + 0x20) = RAT_ERRATA2437_CTRL;
> +
> +		/* Enable DSP_X_DEBUG_CLKEN_OVERRIDE for C71x cores */
> +		*(unsigned int *)(RAT_ERRATA2437_IN_ADDR + 0x200) = 0x00000300;
> +
> +		/* Clear RAT mapping */
> +		*(unsigned int *)(RAT_ERRATA2437_BASE_REGION0 + 0x20) = 0x0;
> +		*(unsigned int *)(RAT_ERRATA2437_BASE_REGION0 + 0x24) = 0x0;
> +		*(unsigned int *)(RAT_ERRATA2437_BASE_REGION0 + 0x28) = 0x0;
> +		*(unsigned int *)(RAT_ERRATA2437_BASE_REGION0 + 0x2c) = 0x0;
> +	}
>   }
>   #endif
>