dell_rbu.rst 4.9 KB

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128
  1. =========================================
  2. Dell Remote BIOS Update driver (dell_rbu)
  3. =========================================
  4. Purpose
  5. =======
  6. Document demonstrating the use of the Dell Remote BIOS Update driver
  7. for updating BIOS images on Dell servers and desktops.
  8. Scope
  9. =====
  10. This document discusses the functionality of the rbu driver only.
  11. It does not cover the support needed from applications to enable the BIOS to
  12. update itself with the image downloaded in to the memory.
  13. Overview
  14. ========
  15. This driver works with Dell OpenManage or Dell Update Packages for updating
  16. the BIOS on Dell servers (starting from servers sold since 1999), desktops
  17. and notebooks (starting from those sold in 2005).
  18. Please go to http://support.dell.com register and you can find info on
  19. OpenManage and Dell Update packages (DUP).
  20. Libsmbios can also be used to update BIOS on Dell systems go to
  21. https://linux.dell.com/libsmbios/ for details.
  22. Dell_RBU driver supports BIOS update using the monolithic image and packetized
  23. image methods. In case of monolithic the driver allocates a contiguous chunk
  24. of physical pages having the BIOS image. In case of packetized the app
  25. using the driver breaks the image in to packets of fixed sizes and the driver
  26. would place each packet in contiguous physical memory. The driver also
  27. maintains a link list of packets for reading them back.
  28. If the dell_rbu driver is unloaded all the allocated memory is freed.
  29. The rbu driver needs to have an application (as mentioned above) which will
  30. inform the BIOS to enable the update in the next system reboot.
  31. The user should not unload the rbu driver after downloading the BIOS image
  32. or updating.
  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. /sys/devices/platform/dell_rbu/packet_size
  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 chunks
  44. of contiguous memory and the BIOS image is scattered in these packets.
  45. By default the driver uses monolithic memory for the update type. This can be
  46. changed to packets during the driver load time by specifying the load
  47. parameter image_type=packet. This can also be changed later as below::
  48. echo packet > /sys/devices/platform/dell_rbu/image_type
  49. In packet update mode the packet size has to be given before any packets can
  50. be downloaded. It is done as below::
  51. echo XXXX > /sys/devices/platform/dell_rbu/packet_size
  52. In the packet update mechanism, the user needs to create a new file having
  53. packets of data arranged back to back. It can be done as follows:
  54. The user creates packets header, gets the chunk of the BIOS image and
  55. places it next to the packetheader; now, the packetheader + BIOS image chunk
  56. added together should match the specified packet_size. This makes one
  57. packet, the user needs to create more such packets out of the entire BIOS
  58. image file and then arrange all these packets back to back in to one single
  59. file.
  60. This file is then copied to /sys/class/firmware/dell_rbu/data.
  61. Once this file gets to the driver, the driver extracts packet_size data from
  62. the file and spreads it across the physical memory in contiguous packet_sized
  63. space.
  64. This method makes sure that all the packets get to the driver in a single operation.
  65. In monolithic update the user simply get the BIOS image (.hdr file) and copies
  66. to the data file as is without any change to the BIOS image itself.
  67. Do the steps below to download the BIOS image.
  68. 1) echo 1 > /sys/class/firmware/dell_rbu/loading
  69. 2) cp bios_image.hdr /sys/class/firmware/dell_rbu/data
  70. 3) echo 0 > /sys/class/firmware/dell_rbu/loading
  71. The /sys/class/firmware/dell_rbu/ entries will remain till the following is
  72. done.
  73. ::
  74. echo -1 > /sys/class/firmware/dell_rbu/loading
  75. Until this step is completed the driver cannot be unloaded.
  76. Also echoing either mono, packet or init in to image_type will free up the
  77. memory allocated by the driver.
  78. If a user by accident executes steps 1 and 3 above without executing step 2;
  79. it will make the /sys/class/firmware/dell_rbu/ entries disappear.
  80. The entries can be recreated by doing the following::
  81. echo init > /sys/devices/platform/dell_rbu/image_type
  82. .. note:: echoing init in image_type does not change its original value.
  83. Also the driver provides /sys/devices/platform/dell_rbu/data readonly file to
  84. read back the image downloaded.
  85. .. note::
  86. After updating the BIOS image a user mode application needs to execute
  87. code which sends the BIOS update request to the BIOS. So on the next reboot
  88. the BIOS knows about the new image downloaded and it updates itself.
  89. Also don't unload the rbu driver if the image has to be updated.