1 ========================================= 2 Dell Remote BIOS Update driver (dell_rbu) 3 ========================================= 4 5 Purpose 6 ======= 7 8 Document demonstrating the use of the Dell Remote BIOS Update driver 9 for updating BIOS images on Dell servers and desktops. 10 11 Scope 12 ===== 13 14 This document discusses the functionality of the rbu driver only. 15 It does not cover the support needed from applications to enable the BIOS to 16 update itself with the image downloaded in to the memory. 17 18 Overview 19 ======== 20 21 This driver works with Dell OpenManage or Dell Update Packages for updating 22 the BIOS on Dell servers (starting from servers sold since 1999), desktops 23 and notebooks (starting from those sold in 2005). 24 25 Please go to http://support.dell.com register and you can find info on 26 OpenManage and Dell Update packages (DUP). 27 28 Libsmbios can also be used to update BIOS on Dell systems go to 29 https://linux.dell.com/libsmbios/ for details. 30 31 Dell_RBU driver supports BIOS update using the monolithic image and packetized 32 image methods. In case of monolithic the driver allocates a contiguous chunk 33 of physical pages having the BIOS image. In case of packetized the app 34 using the driver breaks the image in to packets of fixed sizes and the driver 35 would place each packet in contiguous physical memory. The driver also 36 maintains a link list of packets for reading them back. 37 38 If the dell_rbu driver is unloaded all the allocated memory is freed. 39 40 The rbu driver needs to have an application (as mentioned above) which will 41 inform the BIOS to enable the update in the next system reboot. 42 43 The user should not unload the rbu driver after downloading the BIOS image 44 or updating. 45 46 The driver load creates the following directories under the /sys file system:: 47 48 /sys/class/firmware/dell_rbu/loading 49 /sys/class/firmware/dell_rbu/data 50 /sys/devices/platform/dell_rbu/image_type 51 /sys/devices/platform/dell_rbu/data 52 /sys/devices/platform/dell_rbu/packet_size 53 54 The driver supports two types of update mechanism; monolithic and packetized. 55 These update mechanism depends upon the BIOS currently running on the system. 56 Most of the Dell systems support a monolithic update where the BIOS image is 57 copied to a single contiguous block of physical memory. 58 59 In case of packet mechanism the single memory can be broken in smaller chunks 60 of contiguous memory and the BIOS image is scattered in these packets. 61 62 By default the driver uses monolithic memory for the update type. This can be 63 changed to packets during the driver load time by specifying the load 64 parameter image_type=packet. This can also be changed later as below:: 65 66 echo packet > /sys/devices/platform/dell_rbu/image_type 67 68 In packet update mode the packet size has to be given before any packets can 69 be downloaded. It is done as below:: 70 71 echo XXXX > /sys/devices/platform/dell_rbu/packet_size 72 73 In the packet update mechanism, the user needs to create a new file having 74 packets of data arranged back to back. It can be done as follows: 75 The user creates packets header, gets the chunk of the BIOS image and 76 places it next to the packetheader; now, the packetheader + BIOS image chunk 77 added together should match the specified packet_size. This makes one 78 packet, the user needs to create more such packets out of the entire BIOS 79 image file and then arrange all these packets back to back in to one single 80 file. 81 82 This file is then copied to /sys/class/firmware/dell_rbu/data. 83 Once this file gets to the driver, the driver extracts packet_size data from 84 the file and spreads it across the physical memory in contiguous packet_sized 85 space. 86 87 This method makes sure that all the packets get to the driver in a single operation. 88 89 In monolithic update the user simply get the BIOS image (.hdr file) and copies 90 to the data file as is without any change to the BIOS image itself. 91 92 Do the steps below to download the BIOS image. 93 94 1) echo 1 > /sys/class/firmware/dell_rbu/loading 95 2) cp bios_image.hdr /sys/class/firmware/dell_rbu/data 96 3) echo 0 > /sys/class/firmware/dell_rbu/loading 97 98 The /sys/class/firmware/dell_rbu/ entries will remain till the following is 99 done. 100 101 :: 102 103 echo -1 > /sys/class/firmware/dell_rbu/loading 104 105 Until this step is completed the driver cannot be unloaded. 106 107 Also echoing either mono, packet or init in to image_type will free up the 108 memory allocated by the driver. 109 110 If a user by accident executes steps 1 and 3 above without executing step 2; 111 it will make the /sys/class/firmware/dell_rbu/ entries disappear. 112 113 The entries can be recreated by doing the following:: 114 115 echo init > /sys/devices/platform/dell_rbu/image_type 116 117 .. note:: echoing init in image_type does not change its original value. 118 119 Also the driver provides /sys/devices/platform/dell_rbu/data readonly file to 120 read back the image downloaded. 121 122 .. note:: 123 124 After updating the BIOS image a user mode application needs to execute 125 code which sends the BIOS update request to the BIOS. So on the next reboot 126 the BIOS knows about the new image downloaded and it updates itself. 127 Also don't unload the rbu driver if the image has to be updated. 128
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