nvme: Add NVM Express driver support

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.

This adds a U-Boot driver support of devices that follow the NVMe
standard [1] and supports basic read/write operations.

Tested with a 400GB Intel SSD 750 series NVMe card with controller
id 8086:0953.

[1] http://www.nvmexpress.org/resources/specifications/

Signed-off-by: Zhikang Zhang <zhikang.zhang@nxp.com>
Signed-off-by: Wenbin Song <wenbin.song@nxp.com>
Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Tom Rini <trini@konsulko.com>

1 files changed, 42 insertions, 0 deletions

diff --git a/doc/README.nvme b/doc/README.nvme
new file mode 100644
index 0000000..d2b917d
--- /dev/null
+++ b/doc/README.nvme
@@ -0,0 +1,42 @@
+#
+# Copyright (C) 2017 NXP Semiconductors
+# Copyright (C) 2017 Bin Meng <bmeng.cn@gmail.com>
+#
+# SPDX-License-Identifier:	GPL-2.0+
+#
+
+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