| .. 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_NVME_PCI Enable PCIe 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 |