1 files changed, 97 insertions, 0 deletions
diff --git a/doc/develop/driver-model/nvme.rst b/doc/develop/driver-model/nvme.rst
new file mode 100644
index 0000000000..736c0a063d
--- /dev/null
+++ b/doc/develop/driver-model/nvme.rst
@@ -0,0 +1,97 @@
+.. SPDX-License-Identifier: GPL-2.0+
+.. Copyright (C) 2017 NXP Semiconductors
+.. Copyright (C) 2017 Bin Meng <bmeng.cn@gmail.com>
+
+NVMe Support
+============
+
+What is NVMe
+------------
+
+NVM Express (NVMe) is a register level interface that allows host software to
+communicate with a non-volatile memory subsystem. This interface is optimized
+for enterprise and client solid state drives, typically attached to the PCI
+express interface. It is a scalable host controller interface designed to
+address the needs of enterprise and client systems that utilize PCI express
+based solid state drives (SSD). The interface provides optimized command
+submission and completion paths. It includes support for parallel operation by
+supporting up to 64K I/O queues with up to 64K commands per I/O queue.
+
+The device is comprised of some number of controllers, where each controller
+is comprised of some number of namespaces, where each namespace is comprised
+of some number of logical blocks. A namespace is a quantity of non-volatile
+memory that is formatted into logical blocks. An NVMe namespace is equivalent
+to a SCSI LUN. Each namespace is operated as an independent "device".
+
+How it works
+------------
+There is an NVMe uclass driver (driver name "nvme"), an NVMe host controller
+driver (driver name "nvme") and an NVMe namespace block driver (driver name
+"nvme-blk"). The host controller driver is supposed to probe the hardware and
+do necessary initialization to put the controller into a ready state at which
+it is able to scan all available namespaces attached to it. Scanning namespace
+is triggered by the NVMe uclass driver and the actual work is done in the NVMe
+namespace block driver.
+
+Status
+------
+It only support basic block read/write functions in the NVMe driver.
+
+Config options
+--------------
+CONFIG_NVME	Enable NVMe device support
+CONFIG_CMD_NVME	Enable basic NVMe commands
+
+Usage in U-Boot
+---------------
+To use an NVMe hard disk from U-Boot shell, a 'nvme scan' command needs to
+be executed for all NVMe hard disks attached to the NVMe controller to be
+identified.
+
+To list all of the NVMe hard disks, try:
+
+.. code-block:: none
+
+  => nvme info
+  Device 0: Vendor: 0x8086 Rev: 8DV10131 Prod: CVFT535600LS400BGN
+	    Type: Hard Disk
+	    Capacity: 381554.0 MB = 372.6 GB (781422768 x 512)
+
+and print out detailed information for controller and namespaces via:
+
+.. code-block:: none
+
+  => nvme detail
+
+Raw block read/write to can be done via the 'nvme read/write' commands:
+
+.. code-block:: none
+
+  => nvme read a0000000 0 11000
+
+  => tftp 80000000 /tftpboot/kernel.itb
+  => nvme write 80000000 0 11000
+
+Of course, file system command can be used on the NVMe hard disk as well:
+
+.. code-block:: none
+
+  => fatls nvme 0:1
+	32376967   kernel.itb
+	22929408   100m
+
+	2 file(s), 0 dir(s)
+
+  => fatload nvme 0:1 a0000000 /kernel.itb
+  => bootm a0000000
+
+Testing NVMe with QEMU x86
+--------------------------
+QEMU supports NVMe emulation and we can test NVMe driver with QEMU x86 running
+U-Boot. Please see README.x86 for how to build u-boot.rom image for QEMU x86.
+
+Example command line to call QEMU x86 below with emulated NVMe device:
+
+.. code-block:: bash
+
+  $ ./qemu-system-i386 -drive file=nvme.img,if=none,id=drv0 -device nvme,drive=drv0,serial=QEMUNVME0001 -bios u-boot.rom