Re: [PATCH v4 09/34] efi: Add EFI uclass for media

Heinrich Schuchardt
2021-11-08T15:39:46Z

On 11/8/21 06:29, AKASHI Takahiro wrote:
> On Sun, Nov 07, 2021 at 09:43:22AM -0700, Simon Glass wrote:
>> Hi Heinrich,
>>
>> On Sun, 7 Nov 2021 at 01:21, Heinrich Schuchardt <xypron.glpk@gmx.de> wrote:
>>>
>>>
>>>
>>> On 11/4/21 04:09, Simon Glass wrote:
>>>> At present UCLASS_EFI is used to represent an EFI filesystem among other
>>>> things. The description of this uclass is "EFI managed devices" which is
>>>> pretty vague. The only driver that uses this uclass is in fact not a real
>>>> U-Boot driver, since its operations do not include a struct udevice.
>>>>
>>>> Rather than mess with this, create a new UCLASS_EFI_MEDIA uclass to handle
>>>> EFI media such as disks. Make this the uclass to use for EFI media so that
>>>> it can be used with 'part list', for example.
>>>>
>>>> The existing implementation using UCLASS_EFI remains as is, for
>>>> discussion.
>>>>
>>>> Signed-off-by: Simon Glass <sjg@chromium.org>
>>>> ---
>>>>
>>>> (no changes since v2)
>>>>
>>>> Changes in v2:
>>>> - Add MAINTAINERS entry
>>>> - Show the correct interface type with 'part list'
>>>> - Update the commit message to explain things better
>>>>
>>>> MAINTAINERS | 3 +++
>>>> arch/sandbox/dts/test.dts | 4 ++++
>>>> disk/part.c | 5 ++++-
>>>> drivers/block/Kconfig | 23 +++++++++++++++++++++++
>>>> drivers/block/Makefile | 3 +++
>>>> drivers/block/blk-uclass.c | 2 +-
>>>> drivers/block/efi-media-uclass.c | 15 +++++++++++++++
>>>> drivers/block/sb_efi_media.c | 20 ++++++++++++++++++++
>>>> include/dm/uclass-id.h | 1 +
>>>> test/dm/Makefile | 1 +
>>>> test/dm/efi_media.c | 24 ++++++++++++++++++++++++
>>>> 11 files changed, 99 insertions(+), 2 deletions(-)
>>>> create mode 100644 drivers/block/efi-media-uclass.c
>>>> create mode 100644 drivers/block/sb_efi_media.c
>>>> create mode 100644 test/dm/efi_media.c
>>>>
>>>> diff --git a/MAINTAINERS b/MAINTAINERS
>>>> index 00ff572d4d2..3e8f10c72fa 100644
>>>> --- a/MAINTAINERS
>>>> +++ b/MAINTAINERS
>>>> @@ -712,8 +712,11 @@ W: https://u-boot.readthedocs.io/en/latest/develop/uefi/u-boot_on_efi.html
>>>> F: board/efi/efi-x86_app
>>>> F: configs/efi-x86_app*
>>>> F: doc/develop/uefi/u-boot_on_efi.rst
>>>> +F: drivers/block/efi-media-uclass.c
>>>> +F: drivers/block/sb_efi_media.c
>>>> F: lib/efi/efi_app.c
>>>> F: scripts/build-efi.sh
>>>> +F: test/dm/efi_media.c
>>>>
>>>> EFI PAYLOAD
>>>> M: Heinrich Schuchardt <xypron.glpk@gmx.de>
>>>> diff --git a/arch/sandbox/dts/test.dts b/arch/sandbox/dts/test.dts
>>>> index 8cd688e8d26..2cea4a43c87 100644
>>>> --- a/arch/sandbox/dts/test.dts
>>>> +++ b/arch/sandbox/dts/test.dts
>>>> @@ -498,6 +498,10 @@
>>>> compatible = "sandbox,clk-ccf";
>>>> };
>>>>
>>>> + efi-media {
>>>> + compatible = "sandbox,efi-media";
>>>> + };
>>>> +
>>>> eth@10002000 {
>>>> compatible = "sandbox,eth";
>>>> reg = <0x10002000 0x1000>;
>>>> diff --git a/disk/part.c b/disk/part.c
>>>> index a6a8f7052bd..2560f6a50bc 100644
>>>> --- a/disk/part.c
>>>> +++ b/disk/part.c
>>>> @@ -296,8 +296,11 @@ static void print_part_header(const char *type, struct blk_desc *dev_desc)
>>>> case IF_TYPE_VIRTIO:
>>>> puts("VirtIO");
>>>> break;
>>>> + case IF_TYPE_EFI:
>>>> + puts("EFI");
>>>> + break;
>>>> default:
>>>> - puts ("UNKNOWN");
>>>> + puts("UNKNOWN");
>>>> break;
>>>> }
>>>> printf (" device %d -- Partition Type: %s\n\n",
>>>> diff --git a/drivers/block/Kconfig b/drivers/block/Kconfig
>>>> index 56a4eec05ac..755fdccb574 100644
>>>> --- a/drivers/block/Kconfig
>>>> +++ b/drivers/block/Kconfig
>>>> @@ -61,6 +61,29 @@ config TPL_BLOCK_CACHE
>>>> help
>>>> This option enables the disk-block cache in TPL
>>>>
>>>> +config EFI_MEDIA
>>>> + bool "Support EFI media drivers"
>>>> + default y if EFI || SANDBOX
>>>> + help
>>>> + Enable this to support media devices on top of UEFI. This enables
>>>> + just the uclass so you also need a specific driver to make this do
>>>> + anything.
>>>> +
>>>> + For sandbox there is a test driver.
>>>> +
>>>> +if EFI_MEDIA
>>>> +
>>>> +config EFI_MEDIA_SANDBOX
>>>> + bool "Sandbox EFI media driver"
>>>> + depends on SANDBOX
>>>> + default y
>>>> + help
>>>> + Enables a simple sandbox media driver, used for testing just the
>>>> + EFI_MEDIA uclass. It does not do anything useful, since sandbox does
>>>> + not actually support running on top of UEFI.
>>>> +
>>>> +endif # EFI_MEDIA
>>>> +
>>>> config IDE
>>>> bool "Support IDE controllers"
>>>> select HAVE_BLOCK_DEVICE
>>>> diff --git a/drivers/block/Makefile b/drivers/block/Makefile
>>>> index 94ab5c6f906..3778633da1d 100644
>>>> --- a/drivers/block/Makefile
>>>> +++ b/drivers/block/Makefile
>>>> @@ -14,3 +14,6 @@ obj-$(CONFIG_IDE) += ide.o
>>>> endif
>>>> obj-$(CONFIG_SANDBOX) += sandbox.o
>>>> obj-$(CONFIG_$(SPL_TPL_)BLOCK_CACHE) += blkcache.o
>>>> +
>>>> +obj-$(CONFIG_EFI_MEDIA) += efi-media-uclass.o
>>>> +obj-$(CONFIG_EFI_MEDIA_SANDBOX) += sb_efi_media.o
>>>> diff --git a/drivers/block/blk-uclass.c b/drivers/block/blk-uclass.c
>>>> index 83682dcc181..2db7ce5de20 100644
>>>> --- a/drivers/block/blk-uclass.c
>>>> +++ b/drivers/block/blk-uclass.c
>>>> @@ -44,7 +44,7 @@ static enum uclass_id if_type_uclass_id[IF_TYPE_COUNT] = {
>>>> [IF_TYPE_SATA] = UCLASS_AHCI,
>>>> [IF_TYPE_HOST] = UCLASS_ROOT,
>>>> [IF_TYPE_NVME] = UCLASS_NVME,
>>>> - [IF_TYPE_EFI] = UCLASS_EFI,
>>>> + [IF_TYPE_EFI] = UCLASS_EFI_MEDIA,
>>>
>>> Don't break existing code. Create a new if_type here.
>>
>> My understanding is that this is not actually used at present. The
>> tests appear to pass without trouble.

None of these tests uses the 'load efi 0:1' command!

The iftype-uclass relationship is used during the look up. Please, stick
to separate if_types per uclass.

Best regards

Heinrich

>>
>> What problem are you seeing?
>
> I can agree with Simon's claim that the notion of UCLASS_EFI sounds vague.
> In my understanding, it is expected to represent any UEFI driver/application
> who will convert "UEFI protocol" to "U-Boot device", the only example
> right now is "efi_block" device.
>
> One of issues that I can see is that any instance of UCLASS_EFI doesn't
> appear in DM tree. I have made an experimental patch which makes UCLASS_EFI
> a pseudo U-Boot device. DM tree would look like:
> root
> |-- 'EFI block driver' (CLASS_EFI for block_io_protocol)
> |-- 'efi_blk' (CLASS_BLK with TYPE_EFI)
>
> This way, the meaning of UCLASS_EFI should be much clearer?
>
> # In fact, the actual implementer of BLOCK_IO_PROTOCOL is
> # a loaded UEFI application, though.
>
> -Takahiro Akashi
>
>> Regards,
>> Simon