Purpose¶

Document demonstrating the use of the Dell Remote BIOS Update driverfor updating BIOS images on Dell servers and desktops.

Scope¶

This document discusses the functionality of the rbu driver only.It does not cover the support needed from applications to enable the BIOS toupdate itself with the image downloaded in to the memory.

Overview¶

This driver works with Dell OpenManage or Dell Update Packages for updatingthe BIOS on Dell servers (starting from servers sold since 1999), desktopsand notebooks (starting from those sold in 2005).

Please go tohttp://support.dell.com register and you can find info onOpenManage and Dell Update packages (DUP).

Libsmbios can also be used to update BIOS on Dell systems go tohttps://linux.dell.com/libsmbios/ for details.

Dell_RBU driver supports BIOS update using the monolithic image and packetizedimage methods. In case of monolithic the driver allocates a contiguous chunkof physical pages having the BIOS image. In case of packetized the appusing the driver breaks the image in to packets of fixed sizes and the driverwould place each packet in contiguous physical memory. The driver alsomaintains a link list of packets for reading them back.

If the dell_rbu driver is unloaded all the allocated memory is freed.

The rbu driver needs to have an application (as mentioned above) which willinform the BIOS to enable the update in the next system reboot.

The user should not unload the rbu driver after downloading the BIOS imageor updating.

The driver load creates the following directories under the /sys file system:

/sys/class/firmware/dell_rbu/loading/sys/class/firmware/dell_rbu/data/sys/devices/platform/dell_rbu/image_type/sys/devices/platform/dell_rbu/data/sys/devices/platform/dell_rbu/packet_size

The driver supports two types of update mechanism; monolithic and packetized.These update mechanism depends upon the BIOS currently running on the system.Most of the Dell systems support a monolithic update where the BIOS image iscopied to a single contiguous block of physical memory.

In case of packet mechanism the single memory can be broken in smaller chunksof contiguous memory and the BIOS image is scattered in these packets.

By default the driver uses monolithic memory for the update type. This can bechanged to packets during the driver load time by specifying the loadparameter image_type=packet. This can also be changed later as below:

echo packet > /sys/devices/platform/dell_rbu/image_type

In packet update mode the packet size has to be given before any packets canbe downloaded. It is done as below:

echo XXXX > /sys/devices/platform/dell_rbu/packet_size

In the packet update mechanism, the user needs to create a new file havingpackets of data arranged back to back. It can be done as follows:The user creates packets header, gets the chunk of the BIOS image andplaces it next to the packetheader; now, the packetheader + BIOS image chunkadded together should match the specified packet_size. This makes onepacket, the user needs to create more such packets out of the entire BIOSimage file and then arrange all these packets back to back in to one singlefile.

This file is then copied to /sys/class/firmware/dell_rbu/data.Once this file gets to the driver, the driver extracts packet_size data fromthe file and spreads it across the physical memory in contiguous packet_sizedspace.

This method makes sure that all the packets get to the driver in a single operation.

In monolithic update the user simply get the BIOS image (.hdr file) and copiesto the data file as is without any change to the BIOS image itself.

Do the steps below to download the BIOS image.

1. echo 1 > /sys/class/firmware/dell_rbu/loading

2. cp bios_image.hdr /sys/class/firmware/dell_rbu/data

3. echo 0 > /sys/class/firmware/dell_rbu/loading

The /sys/class/firmware/dell_rbu/ entries will remain till the following isdone.

echo -1 > /sys/class/firmware/dell_rbu/loading

Until this step is completed the driver cannot be unloaded.

Also echoing either mono, packet or init in to image_type will free up thememory allocated by the driver.

If a user by accident executes steps 1 and 3 above without executing step 2;it will make the /sys/class/firmware/dell_rbu/ entries disappear.

The entries can be recreated by doing the following:

echo init > /sys/devices/platform/dell_rbu/image_type

Also the driver provides /sys/devices/platform/dell_rbu/data readonly file toread back the image downloaded.