[PATCH] i2c: smbus: Log (LP)DDR5 type specific unimplemented message in `i2c_register_spd()`

From: Paul Menzel
Date: Thu May 30 2024 - 14:35:32 EST

On several systems Linux logs:

i2c i2c-0: Memory type 0x22 not supported yet, not instantiating SPD

1. Supermicro Super Server/X13SAE, BIOS 2.0 10/17/2022
2. Dell Inc. Precision 3660/0PRR48, BIOS 2.9.3 11/22/2023
3. Dell Inc. OptiPlex SFF Plus 7010/0YGWFV, BIOS 1.7.1 08/11/2023
4. Run `git grep 'emory type.*supported yet, not instantiating SPD'` in
the repository of dmesg reports for various computers collected by
Linux users at https://linux-hardware.org. [1]

Add 0x22 and 0x23 as memory types for DDR5 according to section 7.18.2
(Memory Device — Type), table 78 in *System Management BIOS (SMBIOS)
Reference Specification*, version 3.6.0 [2]. These use JEDEC JESD300-5 for
SPD, and, currently, no driver exists, so add a specific warning for this
case.

Successfully tested on Supermicro Super Server/X13SAE, BIOS 2.0 10/17/2022:

i2c i2c-0: (LP)DDR5 SPD (memory type 0x22) not supported. JEDEC JESD300-5 compatible driv er does not exist yet, not instantiating SPD

$ sudo dmidecode -t memory
# dmidecode 3.3
Getting SMBIOS data from sysfs.
SMBIOS 3.5.0 present.
# SMBIOS implementations newer than version 3.3.0 are not
# fully supported by this version of dmidecode.

Handle 0x001C, DMI type 16, 23 bytes
Physical Memory Array
Location: System Board Or Motherboard
Use: System Memory
Error Correction Type: None
Maximum Capacity: 128 GB
Error Information Handle: Not Provided
Number Of Devices: 4

Handle 0x001D, DMI type 17, 92 bytes
Memory Device
Array Handle: 0x001C
Error Information Handle: Not Provided
Total Width: 64 bits
Data Width: 64 bits
Size: 32 GB
Form Factor: DIMM
Set: None
Locator: DIMMA1
Bank Locator: P0_Node0_Channel0_Dimm0
Type: <OUT OF SPEC>
Type Detail: Synchronous Unbuffered (Unregistered)
Speed: 4800 MT/s
Manufacturer: Samsung
Serial Number: 80CE01225004143D90
Asset Tag: 9876543210
Part Number: M323R4GA3BB0-CQKOL
Rank: 2
Configured Memory Speed: 3600 MT/s
Minimum Voltage: 1.1 V
Maximum Voltage: 1.1 V
Configured Voltage: 1.1 V
Memory Technology: DRAM
Memory Operating Mode Capability: Volatile memory
Firmware Version: Not Specified
Module Manufacturer ID: Bank 1, Hex 0xCE
Module Product ID: Unknown
Memory Subsystem Controller Manufacturer ID: Unknown
Memory Subsystem Controller Product ID: Unknown
Non-Volatile Size: None
Volatile Size: 32 GB
Cache Size: None
Logical Size: None

Handle 0x001E, DMI type 17, 92 bytes
Memory Device
Array Handle: 0x001C
Error Information Handle: Not Provided
Total Width: 64 bits
Data Width: 64 bits
Size: 32 GB
Form Factor: DIMM
Set: None
Locator: DIMMA2
Bank Locator: P0_Node0_Channel0_Dimm1
Type: <OUT OF SPEC>
Type Detail: Synchronous Unbuffered (Unregistered)
Speed: 4800 MT/s
Manufacturer: Samsung
Serial Number: 80CE01225004143D96
Asset Tag: 9876543210
Part Number: M323R4GA3BB0-CQKOL
Rank: 2
Configured Memory Speed: 3600 MT/s
Minimum Voltage: 1.1 V
Maximum Voltage: 1.1 V
Configured Voltage: 1.1 V
Memory Technology: DRAM
Memory Operating Mode Capability: Volatile memory
Firmware Version: Not Specified
Module Manufacturer ID: Bank 1, Hex 0xCE
Module Product ID: Unknown
Memory Subsystem Controller Manufacturer ID: Unknown
Memory Subsystem Controller Product ID: Unknown
Non-Volatile Size: None
Volatile Size: 32 GB
Cache Size: None
Logical Size: None

Handle 0x001F, DMI type 17, 92 bytes
Memory Device
Array Handle: 0x001C
Error Information Handle: Not Provided
Total Width: 64 bits
Data Width: 64 bits
Size: 32 GB
Form Factor: DIMM
Set: None
Locator: DIMMB1
Bank Locator: P0_Node0_Channel1_Dimm0
Type: <OUT OF SPEC>
Type Detail: Synchronous Unbuffered (Unregistered)
Speed: 4800 MT/s
Manufacturer: Samsung
Serial Number: 80CE01225004142720
Asset Tag: 9876543210
Part Number: M323R4GA3BB0-CQKOL
Rank: 2
Configured Memory Speed: 3600 MT/s
Minimum Voltage: 1.1 V
Maximum Voltage: 1.1 V
Configured Voltage: 1.1 V
Memory Technology: DRAM
Memory Operating Mode Capability: Volatile memory
Firmware Version: Not Specified
Module Manufacturer ID: Bank 1, Hex 0xCE
Module Product ID: Unknown
Memory Subsystem Controller Manufacturer ID: Unknown
Memory Subsystem Controller Product ID: Unknown
Non-Volatile Size: None
Volatile Size: 32 GB
Cache Size: None
Logical Size: None

Handle 0x0020, DMI type 17, 92 bytes
Memory Device
Array Handle: 0x001C
Error Information Handle: Not Provided
Total Width: 64 bits
Data Width: 64 bits
Size: 32 GB
Form Factor: DIMM
Set: None
Locator: DIMMB2
Bank Locator: P0_Node0_Channel1_Dimm1
Type: <OUT OF SPEC>
Type Detail: Synchronous Unbuffered (Unregistered)
Speed: 4800 MT/s
Manufacturer: Samsung
Serial Number: 80CE0122500414276A
Asset Tag: 9876543210
Part Number: M323R4GA3BB0-CQKOL
Rank: 2
Configured Memory Speed: 3600 MT/s
Minimum Voltage: 1.1 V
Maximum Voltage: 1.1 V
Configured Voltage: 1.1 V
Memory Technology: DRAM
Memory Operating Mode Capability: Volatile memory
Firmware Version: Not Specified
Module Manufacturer ID: Bank 1, Hex 0xCE
Module Product ID: Unknown
Memory Subsystem Controller Manufacturer ID: Unknown
Memory Subsystem Controller Product ID: Unknown
Non-Volatile Size: None
Volatile Size: 32 GB
Cache Size: None
Logical Size: None

[1]: https://github.com/linuxhw/Dmesg
[2]: https://www.dmtf.org/sites/default/files/standards/documents/DSP0134_3.6.0.pdf

Cc: Jean Delvare <jdelvare@xxxxxxx>
Link: https://lore.kernel.org/all/20240427094603.b266oz2d5oaar4b3@ninjato/
Signed-off-by: Paul Menzel <pmenzel@xxxxxxxxxxxxx>
---
drivers/i2c/i2c-smbus.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/i2c/i2c-smbus.c b/drivers/i2c/i2c-smbus.c
index 97f338b123b11..f87f8e1383cc7 100644
--- a/drivers/i2c/i2c-smbus.c
+++ b/drivers/i2c/i2c-smbus.c
@@ -308,7 +308,7 @@ EXPORT_SYMBOL_GPL(i2c_free_slave_host_notify_device);
* target systems are the same.
* Restrictions to automatic SPD instantiation:
* - Only works if all filled slots have the same memory type
- * - Only works for DDR, DDR2, DDR3 and DDR4 for now
+ * - Only works for DDR, DDR2, DDR3, DDR4 and DDR5 for now
* - Only works on systems with 1 to 8 memory slots
*/
#if IS_ENABLED(CONFIG_DMI)
@@ -382,6 +382,12 @@ void i2c_register_spd(struct i2c_adapter *adap)
case 0x1E: /* LPDDR4 */
name = "ee1004";
break;
+ case 0x22: /* DDR5 */
+ case 0x23: /* LPDDR5 */
+ dev_info(&adap->dev,
+ "(LP)DDR5 SPD (memory type 0x%02x) not supported. JEDEC JESD300-5 compatible driver does not exist yet, not instantiating SPD\n",
+ common_mem_type);
+ return;
default:
dev_info(&adap->dev,
"Memory type 0x%02x not supported yet, not instantiating SPD\n",
--
2.40.1