Re: [PATCH 1/3] EDAC/loongson: Encode node and MC info into mc_idx

在 2026/8/3 16:25, Huacai Chen 写道:
> Hi, Qunqin,
>
> On Thu, Jul 30, 2026 at 2:45 PM Qunqin Zhao <[email protected]> wrote:
>> From: Wang Jinwei <[email protected]>
>>
>> On Loongson multi-node systems, memory controllers are distributed
>> across multiple nodes. Encode node and MC information into mc_idx
>> so that sysfs entries uniquely identify each controller.
>>
>> The driver gets mc-idx from ACPI _DSD property 'mc-idx' if firmware
>> provides it. If not, it falls back to edac_device_alloc_index() for
>> legacy firmware compatibility.
>>
>> The number of memory controllers per node (mc-per-node) is obtained
>> from firmware via ACPI _DSD property, with a default of 4 for
>> backward compatibility. The node and MC IDs are decoded from mc_idx:
>>       node = mc_idx / mc_per_node
>>       mc = mc_idx % mc_per_node
>>
>> For example, with mc-per-node=4:
>>       mc-idx 0-3   -> node0 mc0-mc3
>>       mc-idx 4-7   -> node1 mc0-mc3
>>       ...
>>       mc-idx 28-31 -> node7 mc0-mc3
>>
>> The dmesg output looks like this：
>> Before: (no _DSD mc-idx)
>> EDAC MC3: 510 CE error on MC#3Channel#0_DIMM#0 (channel:0 slot:0
>> page:0x0 offset:0x0 grain:8 syndrome:0x0)
>>
>> After: (_DSD mc-idx)
>> EDAC MC3: 510 CE error on MC#3Channel#0_DIMM#0 (channel:0 slot:0
>> page:0x0 offset:0x0 grain:8 syndrome:0x0 - node:0 mc:3)
>>
>> Cc: Yulong Wang <[email protected]>
>> Cc: Dongyan Qian <[email protected]>
>> Cc: Chao Li <[email protected]>
>> Signed-off-by: Wang Jinwei <[email protected]>
>> Signed-off-by: Qunqin Zhao <[email protected]>
>> ---
>>   drivers/edac/loongson_edac.c | 38 +++++++++++++++++++++++++++++++-----
>>   1 file changed, 33 insertions(+), 5 deletions(-)
>>
>> diff --git a/drivers/edac/loongson_edac.c b/drivers/edac/loongson_edac.c
>> index 38745800ed..f2452e98f5 100644
>> --- a/drivers/edac/loongson_edac.c
>> +++ b/drivers/edac/loongson_edac.c
>> @@ -9,6 +9,7 @@
>>   #include <linux/io-64-nonatomic-lo-hi.h>
>>   #include <linux/module.h>
>>   #include <linux/platform_device.h>
>> +#include <linux/property.h>
>>   #include "edac_module.h"
>>
>>   #define ECC_CS_COUNT_REG       0x18
>> @@ -23,6 +24,8 @@ struct loongson_edac_pvt {
>>           * register state.
>>           */
>>          int last_ce_count;
>> +       int mc_per_node;
> I think mcs_per_node is better than mc_per_node.
>
>> +       bool mc_idx_valid;
>>   };
>>
>>   static int read_ecc(struct mem_ctl_info *mci)
>> @@ -44,7 +47,8 @@ static int read_ecc(struct mem_ctl_info *mci)
>>   static void edac_check(struct mem_ctl_info *mci)
>>   {
>>          struct loongson_edac_pvt *pvt = mci->pvt_info;
>> -       int new, add;
>> +       char other_detail[64];
> Use char other_detail[64] = {0}, then we can drop the 'else' branch below.
>
>> +       int new, add, node, mc;
>>
>>          new = read_ecc(mci);
>>          add = new - pvt->last_ce_count;
>> @@ -52,8 +56,17 @@ static void edac_check(struct mem_ctl_info *mci)
>>          if (add <= 0)
>>                  return;
>>
>> +       if (pvt->mc_idx_valid) {
>> +               node = mci->mc_idx / pvt->mc_per_node;
>> +               mc = mci->mc_idx % pvt->mc_per_node;
>> +               snprintf(other_detail, sizeof(other_detail),
>> +                               "node:%d mc:%d", node, mc);
> The snprintf() can be put in oneline.
>
>> +       } else {
>> +               other_detail[0] = '\0';
>> +       }
>> +
>>          edac_mc_handle_error(HW_EVENT_ERR_CORRECTED, mci, add,
>> -                            0, 0, 0, 0, 0, -1, "error", "");
>> +                            0, 0, 0, 0, 0, -1, "error", other_detail);
>>   }
>>
>>   static void dimm_config_init(struct mem_ctl_info *mci)
>> @@ -72,20 +85,26 @@ static void dimm_config_init(struct mem_ctl_info *mci)
>>          dimm->grain = 8;
>>   }
>>
>> -static void pvt_init(struct mem_ctl_info *mci, void __iomem *vbase)
>> +static void pvt_init(struct mem_ctl_info *mci, void __iomem *vbase,
>> +               bool mc_idx_valid, int mc_per_node)
> The function definition can be put in one line.
>
>>   {
>>          struct loongson_edac_pvt *pvt = mci->pvt_info;
>>
>>          pvt->ecc_base = vbase;
>>          pvt->last_ce_count = read_ecc(mci);
>> +       pvt->mc_idx_valid = mc_idx_valid;
>> +       pvt->mc_per_node = mc_per_node;
>>   }
>>
>>   static int edac_probe(struct platform_device *pdev)
>>   {
>>          struct edac_mc_layer layers[2];
>>          struct mem_ctl_info *mci;
>> +       struct device *dev = &pdev->dev;
>>          void __iomem *vbase;
>> +       u32 mc_per_node;
>>          int ret;
>> +       bool mc_idx_valid;
> Use bool mc_idx_valid = true, then we can drop the 'else' branch below.

Will fix all,

Thanks

>
> Huacai
>
>
>