[U-Boot] [RFC v2 00/15] dm, efi: integrate efi objects into DM
Heinrich Schuchardt
xypron.glpk at gmx.de
Tue Feb 12 09:47:44 UTC 2019
On 2/12/19 8:24 AM, AKASHI Takahiro wrote:
> Hi Heinrich, Simon,
>
> On Sat, Feb 09, 2019 at 05:00:33PM -0600, Simon Glass wrote:
>> Hi Heinrich,
>>
>> On Fri, 8 Feb 2019 at 03:36, Heinrich Schuchardt <xypron.glpk at gmx.de> wrote:
>>>
>>>
>>>
>>> On 2/8/19 9:15 AM, AKASHI Takahiro wrote:
>>>> # bootefi doesn't work with this patch set yet
>>>>
>>>> This patch set came from the past discussion[1] on my "removable device
>>>> support" patch and is intended to be an attempt to integrate efi objects
>>>> into u-boot's Driver Model as much seamlessly as possible.
>>>>
>>>> [1] https://lists.denx.de/pipermail/u-boot/2019-January/354010.html
>>>>
>>>> Since this patch is a prototype (or POC, Proof-Of-Concept), the aim here
>>>> is to discuss further about how in a better shape we will be able to
>>>> merge the two worlds.
>>>>
>>>> After RFC, Simon suggested that efi protocols could be also presented
>>>> as DM devices. This is a major change in RFC v2.
>>>>
>>> Hello Takahiro,
>>>
>>> thanks a lot for laying out your thoughts about a possible integration of
>>> the EFI subsystem and the driver model. Thanks also for providing a first
>>> implementation.
>>
>> Yes indeed. It is very clever what you have been able to do Takahiro.
>
> I think that I'm going to extremes here :)
The other extreme is what EDK2 does. They live with an EFI only model.
I think moving the DM model in this direction would be feasible and
would be much more consistent than trying to map EFI objects onto DM
structures with different semantics. But I do not see the man power to
do such a change.
Between the two extremes is:
- link the worlds via pointers
- move protocol implementations into the respective uclasses
- endow these uclasses with an implementation of the driver
binding protocol
This is feasible with the available capacity and sufficient to cover
your use case of plugable devices.
>
> I wonder what the EFI world will look like if all the handles
> and protocols are also DM devices.
> I don't expect that my patch will be upstreamed any time soon
> (or possibly forever not) So, instead of claiming the change
> would be meaningless, I'd welcome any suggestions, like what will
> happen if we merge/integrate EFI's A with U-Boot's B?
>
> I'm willing to make best efforts to give such an idea a reality
> if possible. Then choices come after that.
>
>>>
>>>> Basic idea is
>>>> * efi_root is a DM device
>>>> * Any efi object, refered to by efi_handle_t in UEFI world,
>>>> has a corresponding DM device.
>>>
>>> EFI applications and drivers will create handles having no relation to
>>> the U-Boot world.
>>
>> I suggest that we change that, i.e. that all devices in existence have
>> a struct udevice. That way DM knows about everything and we don't have
>> the strange parallel 'EFI' world. I don't see any need for it.
>
> Simply, it would be nice that we can list all the applications
> and drivers loaded at one place, akin to linux's
> * ls /proc/
> * cat /proc/modules
>
> (From the viewpoint of API, we can do that just by calling
> locate_handle(BY_PROTOCOL, EFI_LOADED_IMAGE, ...) though.)
>
>>>
>>>> - define efi_handle_t as "struct udevice *"
>>>
>>> An EFI handle does not necessarily relate to any U-Boot device. Why
>>> should a handle which has not backing device carry the extra fields of
>>> struct udevice?
>>
>> Because this is the U-Boot driver model. We should not have an EFI
>> parallel to DM and certainly not just to save a few dozen bytes of
>> data space. If you were trying to save data space, you would not use
>> EFI :-)
>
> Ah, thank you.
>>From a viewpoint of implementation, the situation where some handles
> are DM devices and some are not could make the efi code, particularly
> boottime.c, quite ugly and complicated.
>
>>>
>>>> - for efi_disk,
>>>> * add "struct efi_disk_obj" to blk_desc
>>>
>>> struct efi_disk_obj * is currently the handle of the block device. So
>>> you only some fields may be moved to blk_desc. But I guess I will find
>>> that in one of the patches.
>
> This is definitely a future work item.
> In this case, however, blk_desc should also be able to represent
> a partition.
>
>>>> - for the objects below, there is only one instance for each and so
>>>> they are currently global data:
>>>> efi_gop_obj,
>>>> efi_net_obj,
>>>
>>> efi_net_obj * is the handle of the network device. In future we should
>>> support multiple network devices.
>
> It will be a natural extension.
>
>>>> simple_text_output_mode
>>>> - for loaded_image,
>>>> * link efi_loaded_image_obj to device's platdata
>>>
>>> An EFI application can create an image out of "nothing". Just create a
>>> handle with InstallProtocolInterface() and then call LoadImage() with a
>>> pointer to some place in memory.
>>>
>>> Many images loaded from the same device may be present at the same time,
>>> e.g. iPXE, GRUB, and Linux.
>
> I don't get your point here, but please notice that a "loaded image"
> is more or less portion of main memory with loaded code.
> iPXE, GRUB and Linux are the same in this respect.
Why do you want to treat such a memory area as a separate device?
>
>>>
>>>>
>>>> * Any efi protocol has a corresponding DM device.
>>>
>>> Protocol implementations are not only provided by U-Boot but also by EFI
>>> applications and driver binaries. And of cause the EFI binaries will
>>> implement a lot of protocols completely unknown to U-Boot. So what
>>> should be the meaning of the above sentence in this context?
>>
>> Can we instead add a uclass for each EFI protocol? Then U-Boot does
>> know about them.
>
> Yeah, I thought about defining an uclass for each EFI protocol.
> Given that a protocol defines a protocol-specific set of function
> interfaces in most cases, it will be natural to define a separate
> uclass.
An EFI binary can implement any EFI protocol that only exists for this
special application. E.g. somebody could write an EFI driver
implementing NVME over TCP.
Requiring that U-Boot has a uclass for every protocol would mean that at
U-Boot compile time you would already have to define which EFI binaries
a user is able to load. E.g. if a uclass for NVME over TCP does not
exist a user would not be able to run above hypothetical binary.
>
> On the other hand, this will make it a bit complicated to determine
> whether a given handle is an efi object or efi protocol in DM tree.
>
In EFI terminology a protocol is not a handle but an abstract interface.
The implementation of a protocol is called protocol interface.
A protocol interface may be installed on one or more handles. But it
should not be enumerated by LocateHandles(SearchType = AllHandles)
> Regarding a protocol "unknown to U-Boot," it is kinda headache
> as we can invent a totally *original* protocol which is unknown at
> compile time of U-Boot.
> That is one of reasons why all the protocols have the same type
> of uclass in my current implementation.
> (I don't think there is any way to define uclass dynamically.)
What is the benefit of protocol interface pointing to a uclass that
doesn't implement the protocol?
>
>>>
>>> Above you suggested that struct udevice * would be used as a handle.
>>> So on which handle is the protocol now installed in your model?
>
> "efi_add_protocol" take a handle as a first argument, which is
> set to a parent of that protocol.
> If a handle is NULL here, a generated protocol handle will be
> temporarily attached to efi_root.
>
>>> For a protocol like the device path protocol which is only a data
>>> structure with no related function modules I do not understand the
>>> benefit of creating a separate sub-device.
>>
>> I think it is only a matter of convenience and to keep things regular.
>
> Unifying device path hierarchy to DM tree is another challenge.
As an application may change the device path protocol of a handle at any
time and we do not want to mess up the DM tree I would not see that this
is possible.
>
>>>
>>>> - link "struct efi_handler" to device's uclass_platdata
>>>
>>> struct efi_handler is an item in the list of protocols installed on a
>>> handle. For some of the protocols installed by an EFI application there
>>> will not be any corresponding uclass.
>>
>> As above, perhaps we should fix that?
>
> As I said above, I recognize that this is an issue.
>
>>>
>>>> - be a child of a efi object (hence DM device) in DM device hierarchy
>>>> so that enumerating protocols belonging to efi object is done by
>>>> traversing the tree.
>>>>
>>>
>>> Above you said a struct udevice * would be a handle. So here you imply
>>> that for each protocol interface you will create an extra handle. That
>>> does not fit the EFI model.
>
> Please don't interpret the concept to such an extent.
> While, say, a GPIO has a DM device (and efi handle in this sense),
> is it also an efi object? No.
>
>>>
>>>> * Any efi object which has a backing DM device should be created
>>>> when that DM device is detected (and probed).
>>>
>>> Detected or probed? This is not the same.
>
> So what is your suggestion here?
U-Boot follows the idea of late probing. So I guess we want an EFI
handle to be created when the DM device is detected and probe it when
the installed protocol is used for the first time.
>
>>>> * For efi_disk (or any object with EFI_BLOCK_IO_PROTOCOL),
>>>> - add UCLASS_PARTITION
>>>> - put partitions under a raw block device
>>>> - partitions as well as raw devices can be efi_disk
>>>
>>> Agreed.
>>>
>>>>
>>>> With those extensive changes, there still exists plenty of
>>>> "wrapper" code. Do you have any idea to reduce it?
>>>>
>>>
>>> The concept presented does not cover:
>>>
>>> - device, drivers, protocols created by EFI applications and
>>> driver binaries
>
> I definitely want to see a good example so that I will investigate.
>
>> Can we create uclasses for each 'protocol'? Is there any reason why we cannot?
>
> I think that I partly answered to you above.
>
>>> - non-DM drivers and devices in U-Boot
>>
>> This doesn't really matter as they will be gone soon. At the risk of
>> repeating myself, EFI support should never have supported non-DM in
>> the first place. It was not the right decision, in my view.
>
> OK
>
>>>
>>> It creates extra handles per installed protocol interface which should
>>> not exist in the EFI world.
>>>
>>> So some rework of the concept is needed.
>>>
>>> I suggest to start smaller:
>>>
>>> - convert partitions to the DM model.
>>
>> This is in later patches from what I can tell.
I would put it at the beginning as it is required for your use case of
plugable devices.
Best regards
Heinrich
>
> Yeah, to some extent.
> As I said above, blk_desc should be extended to support disk
> partitions on its own.
>
>>> - provide a pointer serving as EFI handle in struct udevice
>>
>> I actually feel that the approach here, while admittedly bold, seems
>> to be a good step forward.
>>
>> Regards,
>> Simon
>>
>>>
>>> Best regards
>>>
>>> Heinrich
>
> Thank both of you for valuable comments.
>
> -Takahiro Akashi
>
>>>
>>>>
>>>> ***** Example operation ******
>>>> (Two scsi disks, one with no partition, one with two partitions)
>>>>
>>>> => efi dev
>>>> EFI: Initializing UCLASS_EFI_DRIVER
>>>> Device Device Path
>>>> ================ ====================
>>>> 000000007eef9470 /VenHw(e61d73b9-a384-4acc-aeab-82e828f3628b)
>>>> => scsi rescan
>>>>
>>>> Reset SCSI
>>>> scanning bus for devices...
>>>> Target spinup took 0 ms.
>>>> Target spinup took 0 ms.
>>>> SATA link 2 timeout.
>>>> SATA link 3 timeout.
>>>> SATA link 4 timeout.
>>>> SATA link 5 timeout.
>>>> AHCI 0001.0000 32 slots 6 ports 1.5 Gbps 0x3f impl SATA mode
>>>> flags: 64bit ncq only
>>>> Device 0: (0:0) Vendor: ATA Prod.: QEMU HARDDISK Rev: 2.5+
>>>> Type: Hard Disk
>>>> Capacity: 16.0 MB = 0.0 GB (32768 x 512)
>>>> Device 0: (1:0) Vendor: ATA Prod.: QEMU HARDDISK Rev: 2.5+
>>>> Type: Hard Disk
>>>> Capacity: 256.0 MB = 0.2 GB (524288 x 512)
>>>> => efi dev
>>>> Device Device Path
>>>> ================ ====================
>>>> 000000007eef9470 /VenHw(e61d73b9-a384-4acc-aeab-82e828f3628b)
>>>> 000000007ef01c90 /VenHw(e61d73b9-a384-4acc-aeab-82e828f3628b)/Scsi(0,0)
>>>> 000000007ef04910 /VenHw(e61d73b9-a384-4acc-aeab-82e828f3628b)/Scsi(1,0)
>>>> 000000007ef04ee0 /VenHw(e61d73b9-a384-4acc-aeab-82e828f3628b)/Scsi(1,0)/HD(335544330,MBR,0x086246ba,0x17ff4f1a0,0x7eee3770)
>>>> 000000007ef055a0 /VenHw(e61d73b9-a384-4acc-aeab-82e828f3628b)/Scsi(1,0)/HD(335544330,MBR,0x086246ba,0x17ff4f1a0,0x7eee3770)
>>>> => dm tree
>>>> Class index Probed Driver Name
>>>> -----------------------------------------------------------
>>>> root 0 [ + ] root_driver root_driver
>>>> simple_bus 0 [ ] generic_simple_bus |-- platform at c000000
>>>> virtio 0 [ + ] virtio-mmio |-- virtio_mmio at a000000
>>>>
>>>> [snip]
>>>>
>>>> pci 0 [ + ] pci_generic_ecam |-- pcie at 10000000
>>>> pci_generi 0 [ ] pci_generic_drv | |-- pci_0:0.0
>>>> virtio 32 [ ] virtio-pci.l | |-- virtio-pci.l#0
>>>> ahci 0 [ + ] ahci_pci | `-- ahci_pci
>>>> scsi 0 [ + ] ahci_scsi | `-- ahci_scsi
>>>> blk 0 [ + ] scsi_blk | |-- ahci_scsi.id0lun0
>>>> efi_protoc 8 [ + ] efi_disk | | |-- BLOCK_IO
>>>> efi_protoc 9 [ + ] efi_device_path | | `-- Scsi(0,0)
>>>> blk 1 [ + ] scsi_blk | `-- ahci_scsi.id1lun0
>>>> efi_protoc 10 [ + ] efi_disk | |-- BLOCK_IO
>>>> efi_protoc 11 [ + ] efi_device_path | |-- Scsi(1,0)
>>>> partition 0 [ + ] blk_partition | |-- ahci_scsi.id1lun0:1
>>>> efi_protoc 12 [ + ] efi_disk | | |-- BLOCK_IO
>>>> efi_protoc 13 [ + ] efi_device_path | | |-- HD(335544330,MBR,0x086246ba,0x17ff4f1a0,0x7eee3770)
>>>> efi_protoc 14 [ + ] efi_simple_file_syst | | `-- SIMPLE_FILE_SYSTEM
>>>> partition 1 [ + ] blk_partition | `-- ahci_scsi.id1lun0:2
>>>> efi_protoc 15 [ + ] efi_disk | |-- BLOCK_IO
>>>> efi_protoc 16 [ + ] efi_device_path | |-- HD(335544330,MBR,0x086246ba,0x17ff4f1a0,0x7eee3770)
>>>> efi_protoc 17 [ + ] efi_simple_file_syst | `-- SIMPLE_FILE_SYSTEM
>>>> rtc 0 [ ] rtc-pl031 |-- pl031 at 9010000
>>>> serial 0 [ ] serial_pl01x |-- pl011 at 9050000
>>>> serial 1 [ + ] serial_pl01x |-- pl011 at 9000000
>>>> efi_protoc 0 [ + ] efi_simple_text_outp | |-- SIMPLE_TEXT_OUTPUT
>>>> efi_protoc 1 [ + ] efi_simple_text_inpu | |-- SIMPLE_TEXT_INPUT
>>>> efi_protoc 2 [ + ] efi_simple_text_inpu | `-- SIMPLE_TEXT_INPUT_EX
>>>> mtd 0 [ + ] cfi_flash |-- flash at 0
>>>> firmware 0 [ + ] psci |-- psci
>>>> sysreset 0 [ ] psci-sysreset | `-- psci-sysreset
>>>> efi 0 [ + ] efi_root `-- UEFI sub system
>>>> efi_protoc 3 [ + ] efi_device_path |-- VenHw(e61d73b9-a384-4acc-aeab-82e828f3628b)
>>>> efi_protoc 4 [ + ] efi_device_path_to_t |-- DEVICE_PATH_TO_TEXT
>>>> efi_protoc 5 [ + ] efi_device_path_util |-- DEVICE_PATH_UTILITIES
>>>> efi_protoc 6 [ + ] efi_unicode_collatio |-- en
>>>> efi_driver 0 [ + ] EFI block driver `-- EFI block driver
>>>> efi_protoc 7 [ + ] efi_driver_binding `-- DRIVER_BINDING
>>>>
>>>>
>>>>
>>>> Thanks,
>>>> -Takahiro Akashi
>>>>
>>>> AKASHI Takahiro (15):
>>>> efi_loader: efi objects and protocols as DM devices
>>>> efi_loader: boottime: convert efi_loaded_image_obj to DM
>>>> efi_loader: image_loader: aligned with DM
>>>> efi_driver: rename UCLASS_EFI to UCLASS_EFI_DRIVER
>>>> efi_loader: convert efi_root_node to DM
>>>> efi_loader: device path: convert efi_device_path to DM
>>>> efi_loader: unicode_collation: converted to DM
>>>> efi_loader: console: convert efi console input/output to DM
>>>> efi_loader: net: convert efi_net_obj to DM
>>>> efi_loader: gop: convert efi_gop_obj to DM
>>>> dm: blk: add UCLASS_PARTITION
>>>> efi_loader: disk: convert efi_disk_obj to DM
>>>> drivers: align block device drivers with DM-efi integration
>>>> efi_driver: converted to DM
>>>> cmd: efidebug: aligned with DM-efi integration
>>>>
>>>> cmd/bootefi.c | 61 +--
>>>> cmd/efidebug.c | 5 +-
>>>> common/usb_storage.c | 27 +-
>>>> drivers/block/blk-uclass.c | 61 +++
>>>> drivers/scsi/scsi.c | 22 +
>>>> drivers/serial/serial-uclass.c | 6 +
>>>> drivers/video/video-uclass.c | 9 +
>>>> include/blk.h | 24 +
>>>> include/dm/device.h | 3 +
>>>> include/dm/uclass-id.h | 6 +-
>>>> include/efi.h | 4 +-
>>>> include/efi_loader.h | 50 +-
>>>> lib/efi_driver/efi_block_device.c | 36 +-
>>>> lib/efi_driver/efi_uclass.c | 37 +-
>>>> lib/efi_loader/efi_boottime.c | 605 ++++++++++++++-------
>>>> lib/efi_loader/efi_console.c | 64 ++-
>>>> lib/efi_loader/efi_device_path.c | 136 +++--
>>>> lib/efi_loader/efi_device_path_to_text.c | 55 ++
>>>> lib/efi_loader/efi_device_path_utilities.c | 14 +
>>>> lib/efi_loader/efi_disk.c | 216 +++++---
>>>> lib/efi_loader/efi_file.c | 14 +
>>>> lib/efi_loader/efi_gop.c | 28 +-
>>>> lib/efi_loader/efi_image_loader.c | 61 ++-
>>>> lib/efi_loader/efi_net.c | 50 +-
>>>> lib/efi_loader/efi_root_node.c | 14 +-
>>>> lib/efi_loader/efi_setup.c | 60 +-
>>>> lib/efi_loader/efi_unicode_collation.c | 19 +
>>>> net/eth-uclass.c | 5 +
>>>> 28 files changed, 1226 insertions(+), 466 deletions(-)
>>>>
>
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