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1 | Purpose: |
2 | Demonstrate the usage of the new open sourced rbu (Remote BIOS Update) driver | |
3 | for updating BIOS images on Dell servers and desktops. | |
4 | ||
5 | Scope: | |
6 | This document discusses the functionality of the rbu driver only. | |
7 | It does not cover the support needed from aplications to enable the BIOS to | |
8 | update itself with the image downloaded in to the memory. | |
9 | ||
10 | Overview: | |
11 | This driver works with Dell OpenManage or Dell Update Packages for updating | |
12 | the BIOS on Dell servers (starting from servers sold since 1999), desktops | |
13 | and notebooks (starting from those sold in 2005). | |
14 | Please go to http://support.dell.com register and you can find info on | |
15 | OpenManage and Dell Update packages (DUP). | |
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16 | Libsmbios can also be used to update BIOS on Dell systems go to |
17 | http://linux.dell.com/libsmbios/ for details. | |
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18 | |
19 | Dell_RBU driver supports BIOS update using the monilothic image and packetized | |
20 | image methods. In case of moniolithic the driver allocates a contiguous chunk | |
21 | of physical pages having the BIOS image. In case of packetized the app | |
22 | using the driver breaks the image in to packets of fixed sizes and the driver | |
23 | would place each packet in contiguous physical memory. The driver also | |
24 | maintains a link list of packets for reading them back. | |
25 | If the dell_rbu driver is unloaded all the allocated memory is freed. | |
26 | ||
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27 | The rbu driver needs to have an application (as mentioned above)which will |
28 | inform the BIOS to enable the update in the next system reboot. | |
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29 | |
30 | The user should not unload the rbu driver after downloading the BIOS image | |
31 | or updating. | |
32 | ||
33 | The 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 | ||
39 | The driver supports two types of update mechanism; monolithic and packetized. | |
40 | These update mechanism depends upon the BIOS currently running on the system. | |
41 | Most of the Dell systems support a monolithic update where the BIOS image is | |
42 | copied to a single contiguous block of physical memory. | |
43 | In case of packet mechanism the single memory can be broken in smaller chuks | |
44 | of contiguous memory and the BIOS image is scattered in these packets. | |
45 | ||
46 | By default the driver uses monolithic memory for the update type. This can be | |
e61c0e33 | 47 | changed to packets during the driver load time by specifying the load |
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48 | parameter image_type=packet. This can also be changed later as below |
49 | echo packet > /sys/devices/platform/dell_rbu/image_type | |
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50 | Also echoing either mono ,packet or init in to image_type will free up the |
51 | memory allocated by the driver. | |
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52 | |
53 | Do the steps below to download the BIOS image. | |
54 | 1) echo 1 > /sys/class/firmware/dell_rbu/loading | |
55 | 2) cp bios_image.hdr /sys/class/firmware/dell_rbu/data | |
56 | 3) echo 0 > /sys/class/firmware/dell_rbu/loading | |
57 | ||
58 | The /sys/class/firmware/dell_rbu/ entries will remain till the following is | |
59 | done. | |
e61c0e33 | 60 | echo -1 > /sys/class/firmware/dell_rbu/loading. |
6c54c28e | 61 | Until this step is completed the drivr cannot be unloaded. |
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62 | If an user by accident executes steps 1 and 3 above without executing step 2; |
63 | it will make the /sys/class/firmware/dell_rbu/ entries to disappear. | |
64 | The entries can be recreated by doing the following | |
65 | echo init > /sys/devices/platform/dell_rbu/image_type | |
66 | NOTE: echoing init in image_type does not change it original value. | |
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67 | |
68 | Also the driver provides /sys/devices/platform/dell_rbu/data readonly file to | |
69 | read back the image downloaded. This is useful in case of packet update | |
70 | mechanism where the above steps 1,2,3 will repeated for every packet. | |
71 | By reading the /sys/devices/platform/dell_rbu/data file all packet data | |
72 | downloaded can be verified in a single file. | |
73 | The packets are arranged in this file one after the other in a FIFO order. | |
74 | ||
75 | NOTE: | |
76 | This driver requires a patch for firmware_class.c which has the addition | |
77 | of request_firmware_nowait_nohotplug function to wortk | |
78 | Also after updating the BIOS image an user mdoe application neeeds to execute | |
79 | code which message the BIOS update request to the BIOS. So on the next reboot | |
80 | the BIOS knows about the new image downloaded and it updates it self. | |
81 | Also don't unload the rbu drive if the image has to be updated. | |
82 |