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399e27dbbd
The ice hardware contains an embedded chip with firmware which can be updated using devlink flash. The firmware which runs on this chip is referred to as the Embedded Management Processor firmware (EMP firmware). Activating the new firmware image currently requires that the system be rebooted. This is not ideal as rebooting the system can cause unwanted downtime. In practical terms, activating the firmware does not always require a full system reboot. In many cases it is possible to activate the EMP firmware immediately. There are a couple of different scenarios to cover. * The EMP firmware itself can be reloaded by issuing a special update to the device called an Embedded Management Processor reset (EMP reset). This reset causes the device to reset and reload the EMP firmware. * PCI configuration changes are only reloaded after a cold PCIe reset. Unfortunately there is no generic way to trigger this for a PCIe device without a system reboot. When performing a flash update, firmware is capable of responding with some information about the specific update requirements. The driver updates the flash by programming a secondary inactive bank with the contents of the new image, and then issuing a command to request to switch the active bank starting from the next load. The response to the final command for updating the inactive NVM flash bank includes an indication of the minimum reset required to fully update the device. This can be one of the following: * A full power on is required * A cold PCIe reset is required * An EMP reset is required The response to the command to switch flash banks includes an indication of whether or not the firmware will allow an EMP reset request. For most updates, an EMP reset is sufficient to load the new EMP firmware without issues. In some cases, this reset is not sufficient because the PCI configuration space has changed. When this could cause incompatibility with the new EMP image, the firmware is capable of rejecting the EMP reset request. Add logic to ice_fw_update.c to handle the response data flash update AdminQ commands. For the reset level, issue a devlink status notification informing the user of how to complete the update with a simple suggestion like "Activate new firmware by rebooting the system". Cache the status of whether or not firmware will restrict the EMP reset for use in implementing devlink reload. Implement support for devlink reload with the "fw_activate" flag. This allows user space to request the firmware be activated immediately. For the .reload_down handler, we will issue a request for the EMP reset using the appropriate firmware AdminQ command. If we know that the firmware will not allow an EMP reset, simply exit with a suitable netlink extended ACK message indicating that the EMP reset is not available. For the .reload_up handler, simply wait until the driver has finished resetting. Logic to handle processing of an EMP reset already exists in the driver as part of its reset and rebuild flows. Implement support for the devlink reload interface with the "fw_activate" action. This allows userspace to request activation of firmware without a reboot. Note that support for indicating the required reset and EMP reset restriction is not supported on old versions of firmware. The driver can determine if the two features are supported by checking the device capabilities report. I confirmed support has existed since at least version 5.5.2 as reported by the 'fw.mgmt' version. Support to issue the EMP reset request has existed in all version of the EMP firmware for the ice hardware. Check the device capabilities report to determine whether or not the indications are reported by the running firmware. If the reset requirement indication is not supported, always assume a full power on is necessary. If the reset restriction capability is not supported, always assume the EMP reset is available. Users can verify if the EMP reset has activated the firmware by using the devlink info report to check that the 'running' firmware version has updated. For example a user might do the following: # Check current version $ devlink dev info # Update the device $ devlink dev flash pci/0000:af:00.0 file firmware.bin # Confirm stored version updated $ devlink dev info # Reload to activate new firmware $ devlink dev reload pci/0000:af:00.0 action fw_activate # Confirm running version updated $ devlink dev info Finally, this change does *not* implement basic driver-only reload support. I did look into trying to do this. However, it requires significant refactor of how the ice driver probes and loads everything. The ice driver probe and allocation flows were not designed with such a reload in mind. Refactoring the flow to support this is beyond the scope of this change. Signed-off-by: Jacob Keller <jacob.e.keller@intel.com> Tested-by: Gurucharan G <gurucharanx.g@intel.com> Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com> |
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Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.