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

[Neha Malcom Francis]

Hi Udit,

On 07/08/25 10:16, Kumar, Udit wrote:
> 
> 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)
> 

This is not part of the memorycontroller node; it is a subnode of the
memory/ node.

> 
>>
>> 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

As mentioned above, it will always be in a single place i.e. memory/
node. The distribution to the different memory controllers is handled by
the driver.

> 
> 
>> +    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 ?
> 

1/8 still changes what ddrss->ecc_regions[0].start implies. So the call
to k3_ddrss_set_ecc_range_r0 is also changed there.
> 
>> +        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

Yes will add comments here, thanks for the review!

> 
>> +        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);
>>       }
>>   

-- 
Thanking You
Neha Malcom Francis