[PATCH v2 8/9] ram: k3-ddrss: Add support for partial inline ECC in multi-DDR systems

[Kumar, Udit]

On 7/30/2025 7:07 PM, Neha Malcom Francis wrote:
> The existing approach does not account for interleaving in the DDRs when
> setting up regions. There is support for MSMC to calculate the regions
> for each DDR, so modify k3_ddrss_probe to set the regions accordingly
> for multi-DDR systems.
>
> Signed-off-by: Neha Malcom Francis <n-francis at ti.com>
> ---
>   drivers/ram/k3-ddrss/k3-ddrss.c | 58 ++++++++++++++++++++++++++++-----
>   1 file changed, 50 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/ram/k3-ddrss/k3-ddrss.c b/drivers/ram/k3-ddrss/k3-ddrss.c
> index 1c2e5e1835b..e00711a2235 100644
> --- a/drivers/ram/k3-ddrss/k3-ddrss.c
> +++ b/drivers/ram/k3-ddrss/k3-ddrss.c
> @@ -828,11 +828,12 @@ static void k3_ddrss_lpddr4_ecc_init(struct k3_ddrss_desc *ddrss)
>   
>   static int k3_ddrss_probe(struct udevice *dev)
>   {
> -	u64 end;
> +	u64 end, bank0, bank1;
>   	int ret;
>   	struct k3_ddrss_desc *ddrss = dev_get_priv(dev);
> -	__maybe_unused u32 ddr_ram_size, ecc_res;
> +	__maybe_unused u32 inst, ddr_ram_size, ecc_res, st;

size of ddr may go above 4G


>   	__maybe_unused struct k3_ddrss_ecc_region *range = &ddrss->ecc_range;
> +	__maybe_unused struct k3_msmc *msmc_parent = NULL;
>   
>   	debug("%s(dev=%p)\n", __func__, dev);
>   
> @@ -873,26 +874,67 @@ static int k3_ddrss_probe(struct udevice *dev)
>   		k3_ddrss_ddr_inline_ecc_base_size_calc(range);
>   
>   		end = ddrss->ecc_range.start + ddrss->ecc_range.range;
> +		inst = ddrss->instance;
>   		ddr_ram_size = ddrss->ddr_ram_size;
>   		ecc_res = ddrss->ecc_reserved_space;
> +		bank0 = ddrss->ddr_bank_base[0];
> +		bank1 = ddrss->ddr_bank_base[1];
>   
>   		if (!range->range) {
>   			/* Configure entire DDR space by default */
>   			debug("%s: Defaulting to protecting entire DDR space using inline ECC\n",
>   			      __func__);
> -			ddrss->ecc_range.start = ddrss->ddr_bank_base[0];
> +			ddrss->ecc_range.start = bank0;
>   			ddrss->ecc_range.range = ddr_ram_size - ecc_res;
>   		} else {
>   			ddrss->ecc_range.start = range->start;
>   			ddrss->ecc_range.range = range->range;
>   		}
>   
> -		if (end > (ddr_ram_size - ecc_res))
> -			ddrss->ecc_regions[0].range = ddr_ram_size - ecc_res;
> -		else
> -			ddrss->ecc_regions[0].range = ddrss->ecc_range.range;
> +		st = ddrss->ecc_range.start;
> +
> +		if (!CONFIG_IS_ENABLED(K3_MULTI_DDR)) {
> +			if (end > (ddr_ram_size - ecc_res))
> +				ddrss->ecc_regions[0].range = ddr_ram_size - ecc_res;
> +			else
> +				ddrss->ecc_regions[0].range = ddrss->ecc_range.range;
>   
> -		ddrss->ecc_regions[0].start = ddrss->ecc_range.start - ddrss->ddr_bank_base[0];
> +			/* Check in which bank we are */
> +			if (st > bank1)
> +				ddrss->ecc_regions[0].start = st - bank1 + ddrss->ddr_bank_size[0];
> +			else
> +				ddrss->ecc_regions[0].start = st - bank0;
> +		} else {
> +			/* For multi-DDR, we rely on MSMC's calculation of regions for each DDR */
> +			msmc_parent = kzalloc(sizeof(msmc_parent), GFP_KERNEL);
> +			if (!msmc_parent)
> +				return -ENOMEM;
> +
> +			msmc_parent = dev_get_priv(dev->parent);
> +			if (!msmc_parent) {
> +				printf("%s: could not get MSMC parent to set up inline ECC regions\n",
> +				       __func__);
> +				kfree(msmc_parent);
> +				return -EINVAL;
> +			}
> +
> +			if (msmc_parent->R0[0].start < 0) {
> +				/* Configure entire DDR space by default */
> +				ddrss->ecc_regions[0].start = ddrss->ddr_bank_base[0];
> +				ddrss->ecc_regions[0].range = ddr_ram_size - ecc_res;
> +			} else {
> +				end = msmc_parent->R0[inst].start + msmc_parent->R0[inst].range;
> +
> +				if (end > (ddr_ram_size - ecc_res))
> +					ddrss->ecc_regions[0].range = ddr_ram_size - ecc_res;
> +				else
> +					ddrss->ecc_regions[0].range = msmc_parent->R0[inst].range;
> +
> +				ddrss->ecc_regions[0].start =  msmc_parent->R0[inst].start;
> +			}
> +
> +			kfree(msmc_parent);
> +		}
>   
>   		k3_ddrss_lpddr4_ecc_init(ddrss);
>   	}