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| -rw-r--r-- | src/usr/i2c/README.md | 38 |
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diff --git a/src/usr/i2c/README.md b/src/usr/i2c/README.md new file mode 100644 index 000000000..598acfb29 --- /dev/null +++ b/src/usr/i2c/README.md @@ -0,0 +1,38 @@ +## P9 I2C attachments (External devieces and driving I2C master engines) + +Each processor has a CFAM I2C master that connects to the FSP in additon to +a Quad I2C master chiptlet that houses 4 PIB I2CM devices. These I2C master +devices connect to the SBE , the VPD , the TPM/PCIE, and the DIMMs. + +### I2C Masters in the P9 Proc Chiplet + +CFAM I2CM_A = FSP + +PIB I2CM_B = SBE seeproms = Engine0 + +PIB I2CM_C = VPD/SBE seeproms = Engine1 + +PIB I2CM_D = TPM/PCIE HotPlug = Engine2 + +PIB I2CM_E = DIMMs = Engine3 + + +### I2C Master Connections + + +**CFAM I2CM_A** - connects to seeprom0(MVPD), seeprom1(SBE), seeprom2(MVPD), +seeprom3(SBE), CXPs (hostboot ignores), GPUs, DIMMs, and the DPSS/Spare + +**PIB I2CM_B** - connects to seeprom1(SBE) and seeprom3(SBE) + +**PIB I2CM_C** - connects to seeprom0(MVPD), seeprom1(SBE), seeprom2(MVPD), +seeprom3(SBE),CXPs (hostboot ignores), GPUs, and the DPSS/Spare + +**PIB I2CM_D** - connects to TPM and PCIe HotPlugs + +**PIB I2CM_E** - connects to DIMMs + + +**NOTE:** many of these devices have multiple masters, becausue of this masters +must handshake before communicating to make sure collisions do not occur. + |
