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Diffstat (limited to 'kernel/Documentation/dell_rbu.txt')
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diff --git a/kernel/Documentation/dell_rbu.txt b/kernel/Documentation/dell_rbu.txt new file mode 100644 index 000000000..d262e22bd --- /dev/null +++ b/kernel/Documentation/dell_rbu.txt @@ -0,0 +1,100 @@ +Purpose: +Demonstrate the usage of the new open sourced rbu (Remote BIOS Update) driver +for updating BIOS images on Dell servers and desktops. + +Scope: +This document discusses the functionality of the rbu driver only. +It does not cover the support needed from applications to enable the BIOS to +update itself with the image downloaded in to the memory. + +Overview: +This driver works with Dell OpenManage or Dell Update Packages for updating +the BIOS on Dell servers (starting from servers sold since 1999), desktops +and notebooks (starting from those sold in 2005). +Please go to http://support.dell.com register and you can find info on +OpenManage and Dell Update packages (DUP). +Libsmbios can also be used to update BIOS on Dell systems go to +http://linux.dell.com/libsmbios/ for details. + +Dell_RBU driver supports BIOS update using the monolithic image and packetized +image methods. In case of monolithic the driver allocates a contiguous chunk +of physical pages having the BIOS image. In case of packetized the app +using the driver breaks the image in to packets of fixed sizes and the driver +would place each packet in contiguous physical memory. The driver also +maintains a link list of packets for reading them back. +If the dell_rbu driver is unloaded all the allocated memory is freed. + +The rbu driver needs to have an application (as mentioned above)which will +inform the BIOS to enable the update in the next system reboot. + +The user should not unload the rbu driver after downloading the BIOS image +or updating. + +The driver load creates the following directories under the /sys file system. +/sys/class/firmware/dell_rbu/loading +/sys/class/firmware/dell_rbu/data +/sys/devices/platform/dell_rbu/image_type +/sys/devices/platform/dell_rbu/data +/sys/devices/platform/dell_rbu/packet_size + +The driver supports two types of update mechanism; monolithic and packetized. +These update mechanism depends upon the BIOS currently running on the system. +Most of the Dell systems support a monolithic update where the BIOS image is +copied to a single contiguous block of physical memory. +In case of packet mechanism the single memory can be broken in smaller chunks +of contiguous memory and the BIOS image is scattered in these packets. + +By default the driver uses monolithic memory for the update type. This can be +changed to packets during the driver load time by specifying the load +parameter image_type=packet. This can also be changed later as below +echo packet > /sys/devices/platform/dell_rbu/image_type + +In packet update mode the packet size has to be given before any packets can +be downloaded. It is done as below +echo XXXX > /sys/devices/platform/dell_rbu/packet_size +In the packet update mechanism, the user needs to create a new file having +packets of data arranged back to back. It can be done as follows +The user creates packets header, gets the chunk of the BIOS image and +places it next to the packetheader; now, the packetheader + BIOS image chunk +added together should match the specified packet_size. This makes one +packet, the user needs to create more such packets out of the entire BIOS +image file and then arrange all these packets back to back in to one single +file. +This file is then copied to /sys/class/firmware/dell_rbu/data. +Once this file gets to the driver, the driver extracts packet_size data from +the file and spreads it across the physical memory in contiguous packet_sized +space. +This method makes sure that all the packets get to the driver in a single operation. + +In monolithic update the user simply get the BIOS image (.hdr file) and copies +to the data file as is without any change to the BIOS image itself. + +Do the steps below to download the BIOS image. +1) echo 1 > /sys/class/firmware/dell_rbu/loading +2) cp bios_image.hdr /sys/class/firmware/dell_rbu/data +3) echo 0 > /sys/class/firmware/dell_rbu/loading + +The /sys/class/firmware/dell_rbu/ entries will remain till the following is +done. +echo -1 > /sys/class/firmware/dell_rbu/loading +Until this step is completed the driver cannot be unloaded. +Also echoing either mono, packet or init in to image_type will free up the +memory allocated by the driver. + +If a user by accident executes steps 1 and 3 above without executing step 2; +it will make the /sys/class/firmware/dell_rbu/ entries disappear. +The entries can be recreated by doing the following +echo init > /sys/devices/platform/dell_rbu/image_type +NOTE: echoing init in image_type does not change it original value. + +Also the driver provides /sys/devices/platform/dell_rbu/data readonly file to +read back the image downloaded. + +NOTE: +This driver requires a patch for firmware_class.c which has the modified +request_firmware_nowait function. +Also after updating the BIOS image a user mode application needs to execute +code which sends the BIOS update request to the BIOS. So on the next reboot +the BIOS knows about the new image downloaded and it updates itself. +Also don't unload the rbu driver if the image has to be updated. + |