+Cc: Florian (as this indeed rang a bell to me) https://lore.kernel.org/all/d84fb798722762862a7fb08f1e343b6a@xxxxxxxxxx/ On Thu, Nov 07, 2024 at 06:51:03PM +0300, Konstantin Aladyshev wrote: > Hello! > > I'm trying to add I2C devices to I2C/SMBus buses via the ACPI SSDT > overlay method. I've managed to do it for the I2C buses, but can't get > it working for the SMBus (PIIX4). > > Now the long description of what I've tried and learned. > > I've successfully managed to add my I2C devices to the I2C buses. In > this case I2C buses are described in the ACPI code of my system like > this: > ``` > Device (I2CF) > { > Name (_HID, "AMDI0010") > Name (_UID, 0x05) > Method (_CRS, 0, Serialized) {...} > Method (_STA, 0, NotSerialized) {...} > } > ``` > > These buses are present in the system as: > ``` > $ i2cdetect -l > i2c-0 unknown Synopsys DesignWare I2C adapter N/A > ... > ``` > > For my custom device (at24 EEPROM) I've created SSDT table: > ``` > DefinitionBlock ("at24.aml", "SSDT", 5, "", "AT24", 1) > { > External (_SB_.I2CF, DeviceObj) > > Scope (\_SB.I2CF) > { > Device (EEP0) { > Name (_HID, "PRP0001") > Name (_DDN, "Atmel AT24 compatible EEPROM") > Name (_CRS, ResourceTemplate () { > I2cSerialBusV2 ( > 0x0050, // I2C Slave Address > ControllerInitiated, > 400000, // Bus speed > AddressingMode7Bit, > "\\_SB.I2CF", // Link to ACPI I2C host controller > 0 > ) > }) > > Name (_DSD, Package () { > ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"), > Package () { > Package () { "compatible", Package() { "atmel,24c128" } }, > } > }) > } > } > } > ``` > > And after I've loaded it via 'acpi_configfs' I can successfully see > EEPROM in the system: > ``` > root@ubuntu-SP3:/home/ubuntu/acpi/custom# hexdump -C > /sys/bus/i2c/devices/i2c-PRP0001\:00/eeprom > 00000000 63 6a a9 05 00 65 14 35 9f 81 a7 60 aa c2 18 d2 |cj...e.5...`....| > 00000010 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................| > * > 00004000 > ``` > > > Now I'm trying to add devices to the SMBus bus. Which in my case is > produced from the i2c_piix4 PCI device: > ``` > $ lspci -s 00:14.0 -vvvxxx > 00:14.0 SMBus: Advanced Micro Devices, Inc. [AMD] FCH SMBus Controller (rev 61) > Subsystem: Advanced Micro Devices, Inc. [AMD] FCH SMBus Controller > Control: I/O+ Mem+ BusMaster- SpecCycle- MemWINV- VGASnoop- > ParErr- Stepping- SERR- FastB2B- DisINTx+ > Status: Cap- 66MHz+ UDF- FastB2B- ParErr- DEVSEL=medium > >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx- > NUMA node: 0 > IOMMU group: 58 > Kernel driver in use: piix4_smbus > Kernel modules: i2c_piix4, sp5100_tco > 00: 22 10 0b 79 03 04 20 02 61 00 05 0c 00 00 80 00 > 10: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > 20: 00 00 00 00 00 00 00 00 00 00 00 00 22 10 0b 79 > 30: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > ``` > > It is described as simple as this in the system ACPI code: > ``` > Device (SMBS) // \_SB_.PCI0.SMBS > { > Name (_ADR, 0x00140000) // _ADR: Address > } > ``` > And produces several I2C busses to the system: > ``` > i2c-7 unknown SMBus PIIX4 adapter port 0 at 0b00 N/A > i2c-8 unknown SMBus PIIX4 adapter port 2 at 0b00 N/A > i2c-9 unknown SMBus PIIX4 adapter port 1 at 0b20 N/A > ``` > > No matter how I've tried, I can't get to add my custom devices to > these SMBus buses. > > Apparently just using "\\_SB.PCI0.SMBS" is not enough for this case. > Maybe I need to somehow create port nodes for this Device? Or maybe it > is not possible at all with the current piix driver? > > Anyway I've started digging and I've noticed that for the I2C device > there are two physical_nodes in the sysfs. Where the 'physical_node' > is a standard folder and 'physical_node1' is a direct link to the > proper i2c bus: > ``` > $ ls -la /sys/bus/acpi/devices/AMDI0010\:03/ > total 0 > drwxr-xr-x 4 root root 0 Nov 7 18:07 . > drwxr-xr-x 294 root root 0 Nov 7 18:05 .. > -r--r--r-- 1 root root 4096 Nov 7 18:06 hid > -r--r--r-- 1 root root 4096 Nov 7 18:06 modalias > -r--r--r-- 1 root root 4096 Nov 7 18:06 path > lrwxrwxrwx 1 root root 0 Nov 7 18:06 physical_node -> > ../../../platform/AMDI0010:03 > lrwxrwxrwx 1 root root 0 Nov 7 18:06 physical_node1 -> > ../../../platform/AMDI0010:03/i2c-1 > drwxr-xr-x 2 root root 0 Nov 7 18:06 power > -r--r--r-- 1 root root 4096 Nov 7 18:06 status > lrwxrwxrwx 1 root root 0 Nov 7 18:05 subsystem -> ../../../../bus/acpi > -rw-r--r-- 1 root root 4096 Nov 7 18:05 uevent > -r--r--r-- 1 root root 4096 Nov 7 18:06 uid > drwxr-xr-x 3 root root 0 Nov 7 18:05 wakeup > > $ ls -la /sys/bus/acpi/devices/AMDI0010\:03/physical_node/ > total 0 > drwxr-xr-x 4 root root 0 Nov 7 18:08 . > drwxr-xr-x 7335 root root 0 Nov 7 18:05 .. > lrwxrwxrwx 1 root root 0 Nov 7 18:05 driver -> > ../../../bus/platform/drivers/i2c_designware > -rw-r--r-- 1 root root 4096 Nov 7 18:08 driver_override > lrwxrwxrwx 1 root root 0 Nov 7 18:08 firmware_node -> > ../../LNXSYSTM:00/LNXSYBUS:00/AMDI0010:03 > drwxr-xr-x 4 root root 0 Nov 7 18:05 i2c-1 > -r--r--r-- 1 root root 4096 Nov 7 18:08 modalias > drwxr-xr-x 2 root root 0 Nov 7 18:08 power > lrwxrwxrwx 1 root root 0 Nov 7 18:05 subsystem -> ../../../bus/platform > -rw-r--r-- 1 root root 4096 Nov 7 18:05 uevent > > $ ls -la /sys/bus/acpi/devices/AMDI0010\:03/physical_node1/ > total 0 > drwxr-xr-x 4 root root 0 Nov 7 18:08 . > drwxr-xr-x 4 root root 0 Nov 7 18:08 .. > --w------- 1 root root 4096 Nov 7 18:08 delete_device > lrwxrwxrwx 1 root root 0 Nov 7 18:08 device -> ../../AMDI0010:03 > lrwxrwxrwx 1 root root 0 Nov 7 18:08 firmware_node -> > ../../../LNXSYSTM:00/LNXSYBUS:00/AMDI0010:03 > drwxr-xr-x 3 root root 0 Nov 7 18:05 i2c-dev > -r--r--r-- 1 root root 4096 Nov 7 18:05 name > --w------- 1 root root 4096 Nov 7 18:08 new_device > drwxr-xr-x 2 root root 0 Nov 7 18:08 power > lrwxrwxrwx 1 root root 0 Nov 7 18:05 subsystem -> ../../../../bus/i2c > -rw-r--r-- 1 root root 4096 Nov 7 18:05 uevent > -r--r--r-- 1 root root 4096 Nov 7 18:08 waiting_for_supplier > ``` > > But in the case of SMBus there is only one 'physical_node' folder (but > 3 i2c buses) : > ``` > $ ls -l /sys/bus/acpi/devices/device\:25/ > total 0 > -r--r--r-- 1 root root 4096 Nov 7 18:07 adr > -r--r--r-- 1 root root 4096 Nov 7 18:07 path > lrwxrwxrwx 1 root root 0 Nov 7 18:07 physical_node -> > ../../../../pci0000:00/0000:00:14.0 > drwxr-xr-x 2 root root 0 Nov 7 18:07 power > lrwxrwxrwx 1 root root 0 Nov 7 18:05 subsystem -> ../../../../../bus/acpi > -rw-r--r-- 1 root root 4096 Nov 7 18:05 uevent > drwxr-xr-x 3 root root 0 Nov 7 18:05 wakeup > > $ ls -l /sys/bus/acpi/devices/device\:25/physical_node/ > total 0 > -r--r--r-- 1 root root 4096 Nov 7 18:07 ari_enabled > -rw-r--r-- 1 root root 4096 Nov 7 18:07 broken_parity_status > -r--r--r-- 1 root root 4096 Nov 7 18:05 class > -rw-r--r-- 1 root root 256 Nov 7 18:07 config > -r--r--r-- 1 root root 4096 Nov 7 18:07 consistent_dma_mask_bits > -rw-r--r-- 1 root root 4096 Nov 7 18:07 d3cold_allowed > -r--r--r-- 1 root root 4096 Nov 7 18:05 device > -r--r--r-- 1 root root 4096 Nov 7 18:07 dma_mask_bits > lrwxrwxrwx 1 root root 0 Nov 7 18:05 driver -> > ../../../bus/pci/drivers/piix4_smbus > -rw-r--r-- 1 root root 4096 Nov 7 18:07 driver_override > -rw-r--r-- 1 root root 4096 Nov 7 18:07 enable > lrwxrwxrwx 1 root root 0 Nov 7 18:07 firmware_node -> > ../../LNXSYSTM:00/LNXSYBUS:00/PNP0A08:00/device:25 > drwxr-xr-x 4 root root 0 Nov 7 18:05 i2c-7 > drwxr-xr-x 4 root root 0 Nov 7 18:05 i2c-8 > drwxr-xr-x 4 root root 0 Nov 7 18:05 i2c-9 > lrwxrwxrwx 1 root root 0 Nov 7 18:07 iommu -> ../0000:00:00.2/iommu/ivhd3 > lrwxrwxrwx 1 root root 0 Nov 7 18:07 iommu_group -> > ../../../kernel/iommu_groups/58 > -r--r--r-- 1 root root 4096 Nov 7 18:07 irq > drwxr-xr-x 2 root root 0 Nov 7 18:07 link > -r--r--r-- 1 root root 4096 Nov 7 18:07 local_cpulist > -r--r--r-- 1 root root 4096 Nov 7 18:07 local_cpus > -r--r--r-- 1 root root 4096 Nov 7 18:07 modalias > -rw-r--r-- 1 root root 4096 Nov 7 18:07 msi_bus > -rw-r--r-- 1 root root 4096 Nov 7 18:07 numa_node > drwxr-xr-x 2 root root 0 Nov 7 18:07 power > -r--r--r-- 1 root root 4096 Nov 7 18:07 power_state > --w--w---- 1 root root 4096 Nov 7 18:07 remove > --w------- 1 root root 4096 Nov 7 18:07 rescan > -r--r--r-- 1 root root 4096 Nov 7 18:05 resource > -r--r--r-- 1 root root 4096 Nov 7 18:07 revision > lrwxrwxrwx 1 root root 0 Nov 7 18:05 subsystem -> ../../../bus/pci > -r--r--r-- 1 root root 4096 Nov 7 18:07 subsystem_device > -r--r--r-- 1 root root 4096 Nov 7 18:07 subsystem_vendor > -rw-r--r-- 1 root root 4096 Nov 7 18:05 uevent > -r--r--r-- 1 root root 4096 Nov 7 18:05 vendor > ``` > > Maybe I need to modify ACPI code somehow to create these > 'physical_nodesX' folders for the relevant i2c-7/8/9 buses? > > Any feedback is appreciated. -- With Best Regards, Andy Shevchenko
