Re: [RESEND v9 1/9] efi_loader: move udevice pointer into struct efi_object

[Takahiro Akashi <takahiro.akashi@linaro.org>]

On Sun, Jul 17, 2022 at 10:09:42AM +0200, Heinrich Schuchardt wrote:
> On 7/15/22 16:47, Masahisa Kojima wrote:
> > This is a preparation patch to provide the unified method
> > to access udevice pointer associated with the block io device.
> > The EFI handles of both EFI block io driver implemented in
> > lib/efi_loader/efi_disk.c and EFI block io driver implemented
> > as EFI payload can posess the udevice pointer in the struct efi_object.
> > 
> > We can use this udevice pointer to get the U-Boot friendly
> > block device name(e.g. mmc 0:1, nvme 0:1) through efi_handle_t.
> > 
> > Signed-off-by: Masahisa Kojima <masahisa.kojima@linaro.org>
> > ---
> > Newly created in v9
> > 
> >   include/efi_loader.h      |  8 ++++++++
> >   lib/efi_loader/efi_disk.c | 20 +++++++++++++-------
> >   2 files changed, 21 insertions(+), 7 deletions(-)
> > 
> > diff --git a/include/efi_loader.h b/include/efi_loader.h
> > index 3a63a1f75f..bba5ffd482 100644
> > --- a/include/efi_loader.h
> > +++ b/include/efi_loader.h
> > @@ -226,6 +226,12 @@ const char *__efi_nesting_dec(void);
> >   #define EFI_CACHELINE_SIZE 128
> >   #endif
> > 
> > +/**
> > + * efi_handle_to_udev - accessor to the DM device associated to the EFI handle
> > + * @handle:	pointer to the EFI handle
> > + */
> > +#define efi_handle_to_udev(handle) (((struct efi_object *)handle)->dev)
> 
> This conversion will hide errors if handle is not of type efi_handle_t.
> We should avoid the conversion and see build time errors instead.
> Please, remove the macro.

I don't think we should remove the macro itself, but only the type casting.

I think it is a good practice to hide an implementation how the relationship
between udev and efi_object is maintained *behind* accessor macros.

> For every handle of type efi_handle_t you can access the field
> handle->dev directly.
> 
> For struct efi_disk_obj we can use disk->header.dev.

This is a good example for hiding the implementation from the rest of code.

> > +
> >   /* Key identifying current memory map */
> >   extern efi_uintn_t efi_memory_map_key;
> > 
> > @@ -375,6 +381,7 @@ enum efi_object_type {
> >    * @protocols:	linked list with the protocol interfaces installed on this
> >    *		handle
> >    * @type:	image type if the handle relates to an image
> > + * @dev:	pointer to the DM device which is associated with this EFI handle
> >    *
> >    * UEFI offers a flexible and expandable object model. The objects in the UEFI
> >    * API are devices, drivers, and loaded images. struct efi_object is our storage
> > @@ -392,6 +399,7 @@ struct efi_object {
> >   	/* The list of protocols */
> >   	struct list_head protocols;
> >   	enum efi_object_type type;
> > +	struct udevice *dev;
> >   };
> > 
> >   enum efi_image_auth_status {
> > diff --git a/lib/efi_loader/efi_disk.c b/lib/efi_loader/efi_disk.c
> > index 1d700b2a6b..a8e8521e3e 100644
> > --- a/lib/efi_loader/efi_disk.c
> > +++ b/lib/efi_loader/efi_disk.c
> > @@ -46,7 +46,6 @@ struct efi_disk_obj {
> >   	struct efi_device_path *dp;
> >   	unsigned int part;
> >   	struct efi_simple_file_system_protocol *volume;
> > -	struct udevice *dev; /* TODO: move it to efi_object */
> 
> ok
> 
> >   };
> > 
> >   /**
> > @@ -124,16 +123,16 @@ static efi_status_t efi_disk_rw_blocks(struct efi_block_io *this,
> >   		return EFI_BAD_BUFFER_SIZE;
> > 
> >   	if (CONFIG_IS_ENABLED(PARTITIONS) &&
> > -	    device_get_uclass_id(diskobj->dev) == UCLASS_PARTITION) {
> > +	    device_get_uclass_id(efi_handle_to_udev(diskobj)) == UCLASS_PARTITION) {
> 
> device_get_uclass_id(diskobj->header.hdev)) == UCLASS_PARTITION) {
> 
> >   		if (direction == EFI_DISK_READ)
> > -			n = dev_read(diskobj->dev, lba, blocks, buffer);
> > +			n = dev_read(efi_handle_to_udev(diskobj), lba, blocks, buffer);
> 
> dev_read(diskobj->header.hdev)
> 
> >   		else
> > -			n = dev_write(diskobj->dev, lba, blocks, buffer);
> > +			n = dev_write(efi_handle_to_udev(diskobj), lba, blocks, buffer);
> 
> dev_write(diskobj->header.hdev)
> 
> >   	} else {
> >   		/* dev is a block device (UCLASS_BLK) */
> >   		struct blk_desc *desc;
> > 
> > -		desc = dev_get_uclass_plat(diskobj->dev);
> > +		desc = dev_get_uclass_plat(efi_handle_to_udev(diskobj));
> 
> dev_get_uclass(diskobj->header.hdev)
> 
> 
> >   		if (direction == EFI_DISK_READ)
> >   			n = blk_dread(desc, lba, blocks, buffer);
> >   		else
> > @@ -552,7 +551,7 @@ static int efi_disk_create_raw(struct udevice *dev)
> > 
> >   		return -1;
> >   	}
> > -	disk->dev = dev;
> > +	efi_handle_to_udev(disk) = dev;
> >   	if (dev_tag_set_ptr(dev, DM_TAG_EFI, &disk->header)) {
> >   		efi_free_pool(disk->dp);
> >   		efi_delete_handle(&disk->header);
> > @@ -609,7 +608,7 @@ static int efi_disk_create_part(struct udevice *dev)
> >   		log_err("Adding partition for %s failed\n", dev->name);
> >   		return -1;
> >   	}
> > -	disk->dev = dev;
> > +	efi_handle_to_udev(disk) = dev;
> 
> disk->header.dev = dev;

It's my preference, but I would suggest another accessor:
       efi_set_udev(handle, dev);
to hide an implementation.

-Takahiro Akashi

> 
> >   	if (dev_tag_set_ptr(dev, DM_TAG_EFI, &disk->header)) {
> >   		efi_free_pool(disk->dp);
> >   		efi_delete_handle(&disk->header);
> > @@ -656,6 +655,13 @@ static int efi_disk_probe(void *ctx, struct event *event)
> >   		ret = efi_disk_create_raw(dev);
> >   		if (ret)
> >   			return -1;
> > +	} else {
> > +		efi_handle_t handle;
> > +
> > +		if (dev_tag_get_ptr(dev, DM_TAG_EFI, (void **)&handle))
> > +			return -1;
> > +
> > +		efi_handle_to_udev(handle) = dev;
> 
> handle->dev = dev;
> 
> Best regards
> 
> Heinrich
> 
> >   	}
> > 
> >   	device_foreach_child(child, dev) {
>