[PATCH v2 4/9] ram: k3-ddrss: Add support for a partial inline ECC region

[Kumar, Udit]

On 7/30/2025 7:07 PM, Neha Malcom Francis wrote:
> Instead of defaulting to choosing the entire DDR region when enabling
> inline ECC, allow picking of a range within the DDR space using DT to
> enable.
>
> It expects such a node within the memory node, in the absence of which
> we resort to enabling inline ECC for the entire DDR region:
>
> inline_ecc: protected at 9e780000 {
>          device_type = "ecc";
>          reg = <0x9e780000 0x0080000>;
>          bootph-all;
> };

Please mention , where you expect this node to available in all 
controller nodes or just one controller (in case of multiple controllers)


>
> Signed-off-by: Neha Malcom Francis <n-francis at ti.com>
> ---
>   drivers/ram/k3-ddrss/k3-ddrss.c | 55 +++++++++++++++++++++++++++++++--
>   1 file changed, 52 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/ram/k3-ddrss/k3-ddrss.c b/drivers/ram/k3-ddrss/k3-ddrss.c
> index a94755c3542..cd117d7eba7 100644
> --- a/drivers/ram/k3-ddrss/k3-ddrss.c
> +++ b/drivers/ram/k3-ddrss/k3-ddrss.c
> @@ -155,6 +155,7 @@ struct k3_ddrss_desc {
>   	lpddr4_obj *driverdt;
>   	lpddr4_config config;
>   	lpddr4_privatedata pd;
> +	struct k3_ddrss_ecc_region ecc_range;
>   	struct k3_ddrss_ecc_region ecc_regions[K3_DDRSS_MAX_ECC_REG];
>   	u64 ecc_reserved_space;
>   	u64 ddr_bank_base[CONFIG_NR_DRAM_BANKS];
> @@ -733,6 +734,30 @@ static void k3_ddrss_ddr_reg_init(struct k3_ddrss_desc *ddrss)
>   	writel(DDRSS_ECC_CTRL_REG_DEFAULT, ddrss->ddrss_ss_cfg + DDRSS_ECC_CTRL_REG);
>   }
>   
> +static void k3_ddrss_ddr_inline_ecc_base_size_calc(struct k3_ddrss_ecc_region *range)
> +{
> +	fdt_addr_t base;
> +	fdt_size_t size;
> +	ofnode node1;
> +
> +	node1 = ofnode_null();
> +
> +	do {
> +		node1 = ofnode_by_prop_value(node1, "device_type", "ecc", 4);
> +	} while (!ofnode_is_enabled(node1));
> +

Depending where you expect node to available, parsing logic may change a 
little


> +	base = ofnode_get_addr_size(node1, "reg", &size);
> +
> +	if (base == FDT_ADDR_T_NONE) {
> +		debug("%s: Failed to get ECC node reg and size\n", __func__);
> +		range->start = 0;
> +		range->range = 0;
> +	} else {
> +		range->start = base;
> +		range->range = size;
> +	}
> +}
> +
>   static void k3_ddrss_lpddr4_ecc_calc_reserved_mem(struct k3_ddrss_desc *ddrss)
>   {
>   	fdtdec_setup_mem_size_base_lowest();
> @@ -782,8 +807,11 @@ static void k3_ddrss_lpddr4_ecc_init(struct k3_ddrss_desc *ddrss)
>   
>   static int k3_ddrss_probe(struct udevice *dev)
>   {
> +	u64 end;
>   	int ret;
>   	struct k3_ddrss_desc *ddrss = dev_get_priv(dev);
> +	__maybe_unused u32 ddr_ram_size, ecc_res;

ddr_ram_size may go above u32

> +	__maybe_unused struct k3_ddrss_ecc_region *range = &ddrss->ecc_range;
>   
>   	debug("%s(dev=%p)\n", __func__, dev);
>   
> @@ -821,9 +849,30 @@ static int k3_ddrss_probe(struct udevice *dev)
>   
>   		k3_ddrss_lpddr4_ecc_calc_reserved_mem(ddrss);
>   
> -		/* Always configure one region that covers full DDR space */
> -		ddrss->ecc_regions[0].start = 0;
> -		ddrss->ecc_regions[0].range = ddrss->ddr_ram_size - ddrss->ecc_reserved_space;

patch 1/8 is remove here, please check if you really need 1/8 ?


> +		k3_ddrss_ddr_inline_ecc_base_size_calc(range);
> +
> +		end = ddrss->ecc_range.start + ddrss->ecc_range.range;
> +		ddr_ram_size = ddrss->ddr_ram_size;
> +		ecc_res = ddrss->ecc_reserved_space;
> +
> +		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.range = ddr_ram_size - ecc_res;
> +		} else {
> +			ddrss->ecc_range.start = range->start;
> +			ddrss->ecc_range.range = range->range;
> +		}
> +

Please add comment here for below code .

I think you are trying to fix, if end goes above one 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];
> +
>   		k3_ddrss_lpddr4_ecc_init(ddrss);
>   	}
>