1Purpose: 2Demonstrate the usage of the new open sourced rbu (Remote BIOS Update) driver 3for updating BIOS images on Dell servers and desktops. 4 5Scope: 6This document discusses the functionality of the rbu driver only. 7It does not cover the support needed from applications to enable the BIOS to 8update itself with the image downloaded in to the memory. 9 10Overview: 11This driver works with Dell OpenManage or Dell Update Packages for updating 12the BIOS on Dell servers (starting from servers sold since 1999), desktops 13and notebooks (starting from those sold in 2005). 14Please go to http://support.dell.com register and you can find info on 15OpenManage and Dell Update packages (DUP). 16Libsmbios can also be used to update BIOS on Dell systems go to 17http://linux.dell.com/libsmbios/ for details. 18 19Dell_RBU driver supports BIOS update using the monolithic image and packetized 20image methods. In case of monolithic the driver allocates a contiguous chunk 21of physical pages having the BIOS image. In case of packetized the app 22using the driver breaks the image in to packets of fixed sizes and the driver 23would place each packet in contiguous physical memory. The driver also 24maintains a link list of packets for reading them back. 25If the dell_rbu driver is unloaded all the allocated memory is freed. 26 27The rbu driver needs to have an application (as mentioned above)which will 28inform the BIOS to enable the update in the next system reboot. 29 30The user should not unload the rbu driver after downloading the BIOS image 31or updating. 32 33The driver load creates the following directories under the /sys file system. 34/sys/class/firmware/dell_rbu/loading 35/sys/class/firmware/dell_rbu/data 36/sys/devices/platform/dell_rbu/image_type 37/sys/devices/platform/dell_rbu/data 38/sys/devices/platform/dell_rbu/packet_size 39 40The driver supports two types of update mechanism; monolithic and packetized. 41These update mechanism depends upon the BIOS currently running on the system. 42Most of the Dell systems support a monolithic update where the BIOS image is 43copied to a single contiguous block of physical memory. 44In case of packet mechanism the single memory can be broken in smaller chunks 45of contiguous memory and the BIOS image is scattered in these packets. 46 47By default the driver uses monolithic memory for the update type. This can be 48changed to packets during the driver load time by specifying the load 49parameter image_type=packet. This can also be changed later as below 50echo packet > /sys/devices/platform/dell_rbu/image_type 51 52In packet update mode the packet size has to be given before any packets can 53be downloaded. It is done as below 54echo XXXX > /sys/devices/platform/dell_rbu/packet_size 55In the packet update mechanism, the user needs to create a new file having 56packets of data arranged back to back. It can be done as follows 57The user creates packets header, gets the chunk of the BIOS image and 58places it next to the packetheader; now, the packetheader + BIOS image chunk 59added together should match the specified packet_size. This makes one 60packet, the user needs to create more such packets out of the entire BIOS 61image file and then arrange all these packets back to back in to one single 62file. 63This file is then copied to /sys/class/firmware/dell_rbu/data. 64Once this file gets to the driver, the driver extracts packet_size data from 65the file and spreads it across the physical memory in contiguous packet_sized 66space. 67This method makes sure that all the packets get to the driver in a single operation. 68 69In monolithic update the user simply get the BIOS image (.hdr file) and copies 70to the data file as is without any change to the BIOS image itself. 71 72Do the steps below to download the BIOS image. 731) echo 1 > /sys/class/firmware/dell_rbu/loading 742) cp bios_image.hdr /sys/class/firmware/dell_rbu/data 753) echo 0 > /sys/class/firmware/dell_rbu/loading 76 77The /sys/class/firmware/dell_rbu/ entries will remain till the following is 78done. 79echo -1 > /sys/class/firmware/dell_rbu/loading 80Until this step is completed the driver cannot be unloaded. 81Also echoing either mono, packet or init in to image_type will free up the 82memory allocated by the driver. 83 84If a user by accident executes steps 1 and 3 above without executing step 2; 85it will make the /sys/class/firmware/dell_rbu/ entries disappear. 86The entries can be recreated by doing the following 87echo init > /sys/devices/platform/dell_rbu/image_type 88NOTE: echoing init in image_type does not change it original value. 89 90Also the driver provides /sys/devices/platform/dell_rbu/data readonly file to 91read back the image downloaded. 92 93NOTE: 94This driver requires a patch for firmware_class.c which has the modified 95request_firmware_nowait function. 96Also after updating the BIOS image a user mode application needs to execute 97code which sends the BIOS update request to the BIOS. So on the next reboot 98the BIOS knows about the new image downloaded and it updates itself. 99Also don't unload the rbu driver if the image has to be updated. 100 101