dell_rbu.txt 4.9 KB

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