Linux 4.15
[linux-2.6-block.git] / Documentation / dell_rbu.txt
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1=============================================================
2Usage of the new open sourced rbu (Remote BIOS Update) driver
3=============================================================
4
5Purpose
6=======
7
8Document demonstrating the use of the Dell Remote BIOS Update driver.
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9for updating BIOS images on Dell servers and desktops.
10
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11Scope
12=====
13
6c54c28e 14This document discusses the functionality of the rbu driver only.
3f6dee9b 15It does not cover the support needed from applications to enable the BIOS to
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16update itself with the image downloaded in to the memory.
17
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18Overview
19========
20
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21This driver works with Dell OpenManage or Dell Update Packages for updating
22the BIOS on Dell servers (starting from servers sold since 1999), desktops
23and notebooks (starting from those sold in 2005).
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25Please go to http://support.dell.com register and you can find info on
26OpenManage and Dell Update packages (DUP).
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28Libsmbios can also be used to update BIOS on Dell systems go to
29http://linux.dell.com/libsmbios/ for details.
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31Dell_RBU driver supports BIOS update using the monolithic image and packetized
32image methods. In case of monolithic the driver allocates a contiguous chunk
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33of physical pages having the BIOS image. In case of packetized the app
34using the driver breaks the image in to packets of fixed sizes and the driver
35would place each packet in contiguous physical memory. The driver also
36maintains a link list of packets for reading them back.
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38If the dell_rbu driver is unloaded all the allocated memory is freed.
39
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40The rbu driver needs to have an application (as mentioned above)which will
41inform the BIOS to enable the update in the next system reboot.
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42
43The user should not unload the rbu driver after downloading the BIOS image
44or updating.
45
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46The 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
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53
54The driver supports two types of update mechanism; monolithic and packetized.
55These update mechanism depends upon the BIOS currently running on the system.
56Most of the Dell systems support a monolithic update where the BIOS image is
57copied to a single contiguous block of physical memory.
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6c28f2c0 59In case of packet mechanism the single memory can be broken in smaller chunks
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60of contiguous memory and the BIOS image is scattered in these packets.
61
62By default the driver uses monolithic memory for the update type. This can be
e61c0e33 63changed to packets during the driver load time by specifying the load
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64parameter image_type=packet. This can also be changed later as below::
65
66 echo packet > /sys/devices/platform/dell_rbu/image_type
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67
68In packet update mode the packet size has to be given before any packets can
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69be downloaded. It is done as below::
70
71 echo XXXX > /sys/devices/platform/dell_rbu/packet_size
72
992caacf 73In the packet update mechanism, the user needs to create a new file having
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74packets of data arranged back to back. It can be done as follows
75The user creates packets header, gets the chunk of the BIOS image and
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76places it next to the packetheader; now, the packetheader + BIOS image chunk
77added together should match the specified packet_size. This makes one
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78packet, the user needs to create more such packets out of the entire BIOS
79image file and then arrange all these packets back to back in to one single
80file.
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82This file is then copied to /sys/class/firmware/dell_rbu/data.
83Once this file gets to the driver, the driver extracts packet_size data from
25985edc 84the file and spreads it across the physical memory in contiguous packet_sized
ad6ce87e 85space.
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87This method makes sure that all the packets get to the driver in a single operation.
88
89In monolithic update the user simply get the BIOS image (.hdr file) and copies
90to the data file as is without any change to the BIOS image itself.
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91
92Do the steps below to download the BIOS image.
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941) echo 1 > /sys/class/firmware/dell_rbu/loading
952) cp bios_image.hdr /sys/class/firmware/dell_rbu/data
963) echo 0 > /sys/class/firmware/dell_rbu/loading
97
98The /sys/class/firmware/dell_rbu/ entries will remain till the following is
99done.
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100
101::
102
103 echo -1 > /sys/class/firmware/dell_rbu/loading
104
ad6ce87e 105Until this step is completed the driver cannot be unloaded.
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1b68bfc1 107Also echoing either mono, packet or init in to image_type will free up the
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108memory allocated by the driver.
109
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110If a user by accident executes steps 1 and 3 above without executing step 2;
111it will make the /sys/class/firmware/dell_rbu/ entries disappear.
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112
113The 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 it original value.
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118
119Also the driver provides /sys/devices/platform/dell_rbu/data readonly file to
ad6ce87e 120read back the image downloaded.
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122.. note::
123
124 This driver requires a patch for firmware_class.c which has the modified
125 request_firmware_nowait function.
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127 Also after updating the BIOS image a user mode application needs to execute
128 code which sends the BIOS update request to the BIOS. So on the next reboot
129 the BIOS knows about the new image downloaded and it updates itself.
130 Also don't unload the rbu driver if the image has to be updated.
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