Hi Takahiro,
On Mon, 11 Oct 2021 at 21:26, AKASHI Takahiro takahiro.akashi@linaro.org wrote:
Simon, Heinrich,
On Mon, Oct 11, 2021 at 10:14:02AM -0600, Simon Glass wrote:
Hi Heinrich,
On Mon, 11 Oct 2021 at 09:09, Heinrich Schuchardt xypron.glpk@gmx.de wrote:
On 10/11/21 16:32, Simon Glass wrote:
Hi Heinrich,
On Mon, 11 Oct 2021 at 04:07, Heinrich Schuchardt xypron.glpk@gmx.de wrote:
On 10/1/21 13:48, Peter Robinson wrote:
On Fri, Oct 1, 2021 at 6:03 AM AKASHI Takahiro takahiro.akashi@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 | | `- mmc@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=nam...
So for a first glimpse at the handling I suggest to use QEMU.
Well that's fine, but every uclass must have a test and a sandbox emulator as well.
Wait, it seems that you're discussing a different thing from my patch.
While I don't know whether NVMe namespaces are a kind of "HW partitions", we don't care much here as long as any namespace can be handled simply as a normal block device, like scsi LUN's, in terms of U-Boot driver model.
# On the other hand, we have to explicitly switch "hw partitions" # with blk_select_hwpart_devnum() on MMC devices even though we use # the *same* udevice(blk_desc). # See do_mmcrpmb() in cmd/mmc.c
So I hope that *your* discussion doesn't make any difference to my patch. Right?
From my POV the patch is fine, which is why I added the review tag.
We should continue the discussion on BLK versus PARTITION.
Regards, Simon