ice: support immediate firmware activation via devlink reload

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>

1 files changed, 22 insertions, 2 deletions

diff --git a/Documentation/networking/devlink/ice.rst b/Documentation/networking/devlink/ice.rst
index 59c78e9717d2..8c082b139bbd 100644
--- a/Documentation/networking/devlink/ice.rst
+++ b/Documentation/networking/devlink/ice.rst
@@ -26,8 +26,10 @@ The ``ice`` driver reports the following versions
     * - ``fw.mgmt``
       - running
       - 2.1.7
-      - 3-digit version number of the management firmware that controls the
-        PHY, link, etc.
+      - 3-digit version number of the management firmware running on the
+        Embedded Management Processor of the device. It controls the PHY,
+        link, access to device resources, etc. Intel documentation refers to
+        this as the EMP firmware.
     * - ``fw.mgmt.api``
       - running
       - 1.5.1
@@ -119,6 +121,24 @@ preserving settings, and thus ``DEVLINK_FLASH_OVERWRITE_IDENTIFIERS`` on its
 own will be rejected. If no overwrite mask is provided, the firmware will be
 instructed to preserve all settings and identifying fields when updating.
 
+Reload
+======
+
+The ``ice`` driver supports activating new firmware after a flash update
+using ``DEVLINK_CMD_RELOAD`` with the ``DEVLINK_RELOAD_ACTION_FW_ACTIVATE``
+action.
+
+.. code:: shell
+
+    $ devlink dev reload pci/0000:01:00.0 reload action fw_activate
+
+The new firmware is activated by issuing a device specific Embedded
+Management Processor reset which requests the device to reset and reload the
+EMP firmware image.
+
+The driver does not currently support reloading the driver via
+``DEVLINK_RELOAD_ACTION_DRIVER_REINIT``.
+
 Regions
 =======