[PATCH v4 02/11] FWU: Add FWU metadata access driver for GPT partitioned block devices

[Sughosh Ganu]

hi Masami,

On Wed, 9 Feb 2022 at 10:26, Masami Hiramatsu
<masami.hiramatsu at linaro.org> wrote:
>
> Hi Sughosh,
>
> While porting mdata-sf driver, I'm confusing on the devicetree
> usage.
>
> 2022年2月8日(火) 3:21 Sughosh Ganu <sughosh.ganu at linaro.org>:
>
> > +int fwu_get_mdata_device(struct udevice **mdata_dev)
> > +{
> > +       u32 phandle;
> > +       int ret, size;
> > +       struct udevice *dev, *child;
> > +       ofnode fwu_mdata_node;
> > +       const fdt32_t *phandle_p = NULL;
> > +
> > +       fwu_mdata_node = ofnode_path("/fwu-mdata");
> > +       if (!ofnode_valid(fwu_mdata_node)) {
> > +               log_err("fwu-node not found\n");
> > +               return -ENOENT;
> > +       }
>
> So this seems to get the udevice from path, but I think fwu-mdata node
> has "u-boot,fwu-mdata" compatible property, in that case probe function
> already gets the node. Why would you search it again by path?

Okay. Is there some other api that I can use which is faster than the
approach currently taken? If so, do let me know.

>
> > +
> > +       phandle_p = ofnode_get_property(fwu_mdata_node, "fwu-mdata-store",
> > +                                       &size);
> > +       if (!phandle_p) {
> > +               log_err("fwu-mdata-store property not found\n");
> > +               return -ENOENT;
> > +       }
> > +
> > +       phandle = fdt32_to_cpu(*phandle_p);
> > +
> > +       ret = device_get_global_by_ofnode(ofnode_get_by_phandle(phandle),
> > +                                         &dev);
> > +       if (ret)
> > +               return ret;
> > +
> > +       ret = -ENODEV;
> > +       for (device_find_first_child(dev, &child); child;
> > +            device_find_next_child(&child)) {
> > +               if (device_get_uclass_id(child) == UCLASS_BLK) {
> > +                       *mdata_dev = child;
>
> I thought that the blk device node directly passed by the
> "fwu-mdata-store" property. Would we need to search it from
> children nodes?

What the device tree is pointing to is the device like the mmc, which
is described through a device tree node. The block device is the child
of this device, which is not described in the device tree. The driver
finally needs the block device.

>
> BTW, if we can use the devicetree, can we define the number of banks
> and the number of images can be described too?

It is much easier to handle if these values are defined through
Kconfig symbols. That way, this gets directly included in the config
file, and can be used directly in the fwu_mdata.h metadata structure.

> Of course as I said in the other thread, I would like to put the
> dfu_alt_info like information in the devicetree too.
> (But it maybe different from this discussion)

Just curious, why do you need to define a variable like dfu_alt_info
in a device tree. If this has already been described earlier, you can
point me to that discussion. Trying to understand what benefit does
having the variables defined in a device tree brings. Thanks.

-sughosh

>
> Thank you,
>
>
> > +                       ret = 0;
> > +               }
> > +       }
> > +
> > +       return ret;
> > +}
> > +
> > +static int fwu_mdata_gpt_blk_probe(struct udevice *dev)
> > +{
> > +       int ret;
> > +       struct udevice *mdata_dev = NULL;
> > +
> > +       ret = fwu_get_mdata_device(&mdata_dev);
> > +       if (ret)
> > +               return ret;
> > +
> > +       dev_set_priv(dev, mdata_dev);
> > +
> > +       return 0;
> > +}
> > +
> > +static const struct fwu_mdata_ops fwu_gpt_blk_ops = {
> > +       .get_image_alt_num = fwu_gpt_get_image_alt_num,
> > +       .mdata_check = fwu_gpt_mdata_check,
> > +       .get_mdata = fwu_gpt_get_mdata,
> > +       .update_mdata = fwu_gpt_update_mdata,
> > +};
> > +
> > +static const struct udevice_id fwu_mdata_ids[] = {
> > +       { .compatible = "u-boot,fwu-mdata" },
>
> > +       { }
> > +};
> > +
> > +U_BOOT_DRIVER(fwu_mdata_gpt_blk) = {
> > +       .name           = "fwu-mdata-gpt-blk",
> > +       .id             = UCLASS_FWU_MDATA,
> > +       .of_match       = fwu_mdata_ids,
> > +       .ops            = &fwu_gpt_blk_ops,
> > +       .probe          = fwu_mdata_gpt_blk_probe,
> > +};
> > diff --git a/include/fwu.h b/include/fwu.h
> > index 5a99c579fc..2c7db2dff9 100644
> > --- a/include/fwu.h
> > +++ b/include/fwu.h
> > @@ -43,6 +43,8 @@ int fwu_get_active_index(u32 *active_idx);
> >  int fwu_update_active_index(u32 active_idx);
> >  int fwu_get_image_alt_num(efi_guid_t image_type_id, u32 update_bank,
> >                           int *alt_num);
> > +int fwu_get_mdata_device(struct udevice **mdata_dev);
> > +int fwu_verify_mdata(struct fwu_mdata *mdata, bool pri_part);
> >  int fwu_mdata_check(void);
> >  int fwu_revert_boot_index(void);
> >  int fwu_accept_image(efi_guid_t *img_type_id, u32 bank);
> > --
> > 2.17.1
> >
>
>
> --
> Masami Hiramatsu