[PATCH v2 3/3] common: Move autoprobe out to board init

[Quentin Schulz]

Hi Simon,

Nitpicks below.

On 11/1/24 12:50 PM, Simon Glass wrote:
> Rather than doing autoprobe within the driver model code, move it out to
> the board-init code. This makes it clear that it is a separate step from
> binding devices.
> 
> For now this is always done twice, before and after relocation, but we
> should discuss whether it might be possible to drop the post-relocation
> probe.
> 
> For boards with SPL, the autoprobe is still done there as well.
> 
> Note that with this change, autoprobe happens after the
> EVT_DM_POST_INIT_R/F events are sent, rather than before.
> 
> Update the docs a little, for this feature.
> 
> Signed-off-by: Simon Glass <sjg at chromium.org>
> ---
> 
> Changes in v2:
> - Add autoprobe to SPL also
> - Leave the function name the same
> - Fix 'Prove' typo
> - Update cover letter since SPL is now covered also
> - Update the documentation too, with a discussion link
> 
>   common/board_f.c                    |  4 ++++
>   common/board_r.c                    |  4 ++++
>   common/spl/spl.c                    |  4 ++++
>   doc/develop/driver-model/design.rst | 15 +++++++++++++++
>   drivers/core/root.c                 | 13 ++++++++++++-
>   include/dm/root.h                   | 10 ++++++++++
>   6 files changed, 49 insertions(+), 1 deletion(-)
> 
> diff --git a/common/board_f.c b/common/board_f.c
> index 1e1aa08530a..974eb4f39e9 100644
> --- a/common/board_f.c
> +++ b/common/board_f.c
> @@ -822,6 +822,10 @@ static int initf_dm(void)
>   	if (ret)
>   		return ret;
>   
> +	ret = dm_autoprobe();
> +	if (ret)
> +		return ret;
> +
>   	if (IS_ENABLED(CONFIG_TIMER_EARLY)) {
>   		ret = dm_timer_init();
>   		if (ret)
> diff --git a/common/board_r.c b/common/board_r.c
> index 62228a723e1..d1507b06f8d 100644
> --- a/common/board_r.c
> +++ b/common/board_r.c
> @@ -241,6 +241,10 @@ static int initr_dm(void)
>   	if (ret)
>   		return ret;
>   
> +	ret = dm_autoprobe();
> +	if (ret)
> +		return ret;
> +
>   	return 0;

return dm_autoprobe();

?

>   }
>   #endif
> diff --git a/common/spl/spl.c b/common/spl/spl.c
> index 1ceb63daf31..c4256f237ee 100644
> --- a/common/spl/spl.c
> +++ b/common/spl/spl.c
> @@ -500,6 +500,10 @@ static int spl_common_init(bool setup_malloc)
>   			debug("dm_init_and_scan() returned error %d\n", ret);
>   			return ret;
>   		}
> +
> +		ret = dm_autoprobe();
> +		if (ret)
> +			return ret;
>   	}
>   
>   	return 0;
> diff --git a/doc/develop/driver-model/design.rst b/doc/develop/driver-model/design.rst
> index 8c2c81d7ac9..1dcac1408ff 100644
> --- a/doc/develop/driver-model/design.rst
> +++ b/doc/develop/driver-model/design.rst
> @@ -842,6 +842,21 @@ steps (see device_probe()):
>         cause the uclass to do some housekeeping to record the device as
>         activated and 'known' by the uclass.
>   
> +For some platforms, certain devices must be probed to get the platform into
> +a working state. To help with this, drivers marked with
> +``DM_FLAG_PROBE_AFTER_BIND`` will be probed immediately after all devices are
> +bound. For now, this happens in each xPL build as well as in U-Boot proper,
> +both before relocation and after relocation.  See the call to ``dm_autoprobe()``
> +for where this is done.
> +
> +Note that autoprobe happens after the ``EVT_DM_POST_INIT_R`` and
> +``EVT_DM_POST_INIT_F`` events are sent, since these events relate to
> +device-binding.
> +
> +See here for discussion of this feature:
> +
> +:Link: https://patchwork.ozlabs.org/project/uboot/patch/20240626235717.272219-1-marex@denx.de/
> +
>   Running stage
>   ^^^^^^^^^^^^^
>   
> diff --git a/drivers/core/root.c b/drivers/core/root.c
> index 2d4f078f97f..371a37fe752 100644
> --- a/drivers/core/root.c
> +++ b/drivers/core/root.c
> @@ -299,6 +299,17 @@ static int dm_probe_devices(struct udevice *dev)
>   	return 0;
>   }
>   
> +int dm_autoprobe(void)
> +{
> +	int ret;
> +
> +	ret = dm_probe_devices(gd->dm_root);
> +	if (ret)
> +		return log_msg_ret("pro", ret);
> +
> +	return 0;

1) Should be log_msg_retz since log_msg_ret will only print the message 
on < 0 and here we test for ret
2) Simplify:

return log_msg_retz("pro", dm_probe_devices(gd->dm_root));

the message won't be printed if the return value is 0.

> +}
> +
>   /**
>    * dm_scan() - Scan tables to bind devices
>    *
> @@ -331,7 +342,7 @@ static int dm_scan(bool pre_reloc_only)
>   	if (ret)
>   		return ret;
>   
> -	return dm_probe_devices(gd->dm_root);
> +	return 0;

Simplify with:

return dm_scan_other(pre_reloc_only);

>   }
>   
>   int dm_init_and_scan(bool pre_reloc_only)
> diff --git a/include/dm/root.h b/include/dm/root.h
> index b2f30a842f5..cd240c6a716 100644
> --- a/include/dm/root.h
> +++ b/include/dm/root.h
> @@ -136,6 +136,16 @@ int dm_scan_other(bool pre_reloc_only);
>    */
>   int dm_init_and_scan(bool pre_reloc_only);
>   
> +/**
> + * dm_autoprobe() - Probe devices which are marked for probe-after-bind
> + *
> + * This probes all devices with a DM_FLAG_PROBE_AFTER_BIND flag. It checks the
> + * entire tree, so parent nodes need not have the flag set.
> + *

Can suggest:
"""
It recursively probes parent nodes, so they do not need to have the flag 
set themselves.
"""
which is what I believe you wanted to say? "Checking the entire tree" 
induces the opposite of "parent nodes need not have the flag set".

Cheers,
Quentin