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109 lines
3.5 KiB
109 lines
3.5 KiB
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IPMB Driver for a Satellite MC |
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The Intelligent Platform Management Bus or IPMB, is an |
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I2C bus that provides a standardized interconnection between |
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different boards within a chassis. This interconnection is |
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between the baseboard management (BMC) and chassis electronics. |
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IPMB is also associated with the messaging protocol through the |
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IPMB bus. |
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The devices using the IPMB are usually management |
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controllers that perform management functions such as servicing |
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the front panel interface, monitoring the baseboard, |
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hot-swapping disk drivers in the system chassis, etc... |
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When an IPMB is implemented in the system, the BMC serves as |
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a controller to give system software access to the IPMB. The BMC |
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sends IPMI requests to a device (usually a Satellite Management |
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Controller or Satellite MC) via IPMB and the device |
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sends a response back to the BMC. |
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For more information on IPMB and the format of an IPMB message, |
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refer to the IPMB and IPMI specifications. |
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IPMB driver for Satellite MC |
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---------------------------- |
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ipmb-dev-int - This is the driver needed on a Satellite MC to |
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receive IPMB messages from a BMC and send a response back. |
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This driver works with the I2C driver and a userspace |
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program such as OpenIPMI: |
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1) It is an I2C slave backend driver. So, it defines a callback |
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function to set the Satellite MC as an I2C slave. |
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This callback function handles the received IPMI requests. |
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2) It defines the read and write functions to enable a user |
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space program (such as OpenIPMI) to communicate with the kernel. |
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Load the IPMB driver |
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-------------------- |
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The driver needs to be loaded at boot time or manually first. |
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First, make sure you have the following in your config file: |
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CONFIG_IPMB_DEVICE_INTERFACE=y |
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1) If you want the driver to be loaded at boot time: |
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a) Add this entry to your ACPI table, under the appropriate SMBus:: |
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Device (SMB0) // Example SMBus host controller |
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{ |
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Name (_HID, "<Vendor-Specific HID>") // Vendor-Specific HID |
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Name (_UID, 0) // Unique ID of particular host controller |
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: |
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: |
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Device (IPMB) |
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{ |
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Name (_HID, "IPMB0001") // IPMB device interface |
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Name (_UID, 0) // Unique device identifier |
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} |
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} |
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b) Example for device tree:: |
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&i2c2 { |
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status = "okay"; |
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ipmb@10 { |
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compatible = "ipmb-dev"; |
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reg = <0x10>; |
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i2c-protocol; |
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}; |
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}; |
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If xmit of data to be done using raw i2c block vs smbus |
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then "i2c-protocol" needs to be defined as above. |
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2) Manually from Linux:: |
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modprobe ipmb-dev-int |
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Instantiate the device |
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---------------------- |
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After loading the driver, you can instantiate the device as |
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described in 'Documentation/i2c/instantiating-devices.rst'. |
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If you have multiple BMCs, each connected to your Satellite MC via |
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a different I2C bus, you can instantiate a device for each of |
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those BMCs. |
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The name of the instantiated device contains the I2C bus number |
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associated with it as follows:: |
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BMC1 ------ IPMB/I2C bus 1 ---------| /dev/ipmb-1 |
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Satellite MC |
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BMC1 ------ IPMB/I2C bus 2 ---------| /dev/ipmb-2 |
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For instance, you can instantiate the ipmb-dev-int device from |
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user space at the 7 bit address 0x10 on bus 2:: |
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# echo ipmb-dev 0x1010 > /sys/bus/i2c/devices/i2c-2/new_device |
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This will create the device file /dev/ipmb-2, which can be accessed |
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by the user space program. The device needs to be instantiated |
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before running the user space program.
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