summaryrefslogtreecommitdiffstats
path: root/Documentation/networking/device_drivers/google/gve.rst
diff options
context:
space:
mode:
Diffstat (limited to 'Documentation/networking/device_drivers/google/gve.rst')
-rw-r--r--Documentation/networking/device_drivers/google/gve.rst82
1 files changed, 82 insertions, 0 deletions
diff --git a/Documentation/networking/device_drivers/google/gve.rst b/Documentation/networking/device_drivers/google/gve.rst
new file mode 100644
index 000000000000..7397c82f4c8f
--- /dev/null
+++ b/Documentation/networking/device_drivers/google/gve.rst
@@ -0,0 +1,82 @@
+.. SPDX-License-Identifier: GPL-2.0+
+
+==============================================================
+Linux kernel driver for Compute Engine Virtual Ethernet (gve):
+==============================================================
+
+Supported Hardware
+===================
+The GVE driver binds to a single PCI device id used by the virtual
+Ethernet device found in some Compute Engine VMs.
+
++--------------+----------+---------+
+|Field | Value | Comments|
++==============+==========+=========+
+|Vendor ID | `0x1AE0` | Google |
++--------------+----------+---------+
+|Device ID | `0x0042` | |
++--------------+----------+---------+
+|Sub-vendor ID | `0x1AE0` | Google |
++--------------+----------+---------+
+|Sub-device ID | `0x0058` | |
++--------------+----------+---------+
+|Revision ID | `0x0` | |
++--------------+----------+---------+
+|Device Class | `0x200` | Ethernet|
++--------------+----------+---------+
+
+PCI Bars
+========
+The gVNIC PCI device exposes three 32-bit memory BARS:
+- Bar0 - Device configuration and status registers.
+- Bar1 - MSI-X vector table
+- Bar2 - IRQ, RX and TX doorbells
+
+Device Interactions
+===================
+The driver interacts with the device in the following ways:
+ - Registers
+ - A block of MMIO registers
+ - See gve_register.h for more detail
+ - Admin Queue
+ - See description below
+ - Interrupts
+ - See supported interrupts below
+
+Registers
+---------
+All registers are MMIO and big endian.
+
+The registers are used for initializing and configuring the device as well as
+querying device status in response to management interrupts.
+
+Admin Queue (AQ)
+----------------
+The Admin Queue is a PAGE_SIZE memory block, treated as an array of AQ
+commands, used by the driver to issue commands to the device and set up
+resources.The driver and the device maintain a count of how many commands
+have been submitted and executed. To issue AQ commands, the driver must do
+the following (with proper locking):
+
+1) Copy new commands into next available slots in the AQ array
+2) Increment its counter by he number of new commands
+3) Write the counter into the GVE_ADMIN_QUEUE_DOORBELL register
+4) Poll the ADMIN_QUEUE_EVENT_COUNTER register until it equals
+ the value written to the doorbell, or until a timeout.
+
+The device will update the status field in each AQ command reported as
+executed through the ADMIN_QUEUE_EVENT_COUNTER register.
+
+Interrupts
+----------
+The following interrupts are supported by the driver:
+
+Management Interrupt
+~~~~~~~~~~~~~~~~~~~~
+The management interrupt is used by the device to tell the driver to
+look at the GVE_DEVICE_STATUS register.
+
+Notification Block Interrupts
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+The notification block interrupts are used to tell the driver to poll
+the queues associated with that interrupt.