On 10/11/21 16:32, Simon Glass wrote:
Hi Heinrich,
On Mon, 11 Oct 2021 at 04:07, Heinrich Schuchardt <xypron.g...@gmx.de> wrote:
On 10/1/21 13:48, Peter Robinson wrote:
On Fri, Oct 1, 2021 at 6:03 AM AKASHI Takahiro
<takahiro.aka...@linaro.org> wrote:
In blk_get_device_by_str(), the comment says: "Updates the partition table
for the specified hw partition."
Since hw partition is supported only on MMC, it makes no sense to do so
for other devices.
Is it not also supported on UFS, and I believe it may also be an
option in the NVME spec too.
An NVMe device may expose multiple namespaces. blk_create_devicef() is
called for each namespace.
A SCSI device may have multiple LUNs. blk_create_devicef() is called for
each LUN.
This is what the tree shown by 'dm tree' with on NVMe namespace and one LUN.
Class Index Driver Name
---------------------------------------------------------------------
root 0 root_driver root_driver
simple_bus 0 simple_bus |- soc
spi 1 sifive_spi | |- spi@10050000
mmc 0 mmc_spi | | `- mmc@0
blk 0 mmc_blk | | `- m...@0.blk
pci 0 pcie_sifive | |- pcie@e00000000
pci 1 pci_bridge_drv | | `- pci_0:0.0
pci 2 pci_bridge_drv | | `- pci_1:0.0
pci 5 pci_bridge_drv | | |- pci_2:3.0
ahci 0 ahci_pci | | | `- ahci_pci
scsi 0 ahci_scsi | | | `- ahci_scsi
blk 2 scsi_blk | | | `- ahci_scsi.id0lun0
pci 6 pci_bridge_drv | | |- pci_2:4.0
nvme 0 nvme | | | `- nvme#0
blk 1 nvme-blk | | | `- nvme#0.blk#1
Namespaces and LUNs are modeled as block devices (class = 'blk').
So multiple block devices per NVMe device? I did not know that was supported.
We need a sandbox driver for NVMe as it has no tests at present. Since
it has no tests, I don't think we can expect people to know how to
maintain whatever functionality is there.
NVMe drives with multiple namespaces exist for servers but not for
consumer NVMe drives.
In QEMU you can define an NVMe device with multiple namespaces. Cf.
https://qemu.readthedocs.io/en/latest/system/devices/nvme.html?highlight=namespace#additional-namespaces
So for a first glimpse at the handling I suggest to use QEMU.
Best regards
Heinrich
