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SubjectRe: [PATCH v1] of: platform: Batch fwnode parsing in the init_machine() path
Hi Saravana,

Thank you for the patch.

On Thu, Oct 01, 2020 at 03:59:51PM -0700, Saravana Kannan wrote:
> When commit 93d2e4322aa7 ("of: platform: Batch fwnode parsing when
> adding all top level devices") optimized the fwnode parsing when all top
> level devices are added, it missed out optimizing this for platform
> where the top level devices are added through the init_machine() path.
>
> This commit does the optimization for all paths by simply moving the
> fw_devlink_pause/resume() inside of_platform_default_populate().

Based on v5.9-rc5, before the patch:

[ 0.652887] cpuidle: using governor menu
[ 12.349476] No ATAGs?

After the patch:

[ 0.650460] cpuidle: using governor menu
[ 12.262101] No ATAGs?

:-(

> Reported-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
> Signed-off-by: Saravana Kannan <saravanak@google.com>
> ---
> drivers/of/platform.c | 19 +++++++++++++++----
> 1 file changed, 15 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/of/platform.c b/drivers/of/platform.c
> index 071f04da32c8..79972e49b539 100644
> --- a/drivers/of/platform.c
> +++ b/drivers/of/platform.c
> @@ -501,8 +501,21 @@ int of_platform_default_populate(struct device_node *root,
> const struct of_dev_auxdata *lookup,
> struct device *parent)
> {
> - return of_platform_populate(root, of_default_bus_match_table, lookup,
> - parent);
> + int ret;
> +
> + /*
> + * fw_devlink_pause/resume() are only safe to be called around top
> + * level device addition due to locking constraints.
> + */
> + if (!root)
> + fw_devlink_pause();
> +
> + ret = of_platform_populate(root, of_default_bus_match_table, lookup,
> + parent);
> +
> + if (!root)
> + fw_devlink_resume();
> + return ret;
> }
> EXPORT_SYMBOL_GPL(of_platform_default_populate);
>
> @@ -538,9 +551,7 @@ static int __init of_platform_default_populate_init(void)
> }
>
> /* Populate everything else. */
> - fw_devlink_pause();
> of_platform_default_populate(NULL, NULL, NULL);
> - fw_devlink_resume();
>
> return 0;
> }

--
Regards,

Laurent Pinchart

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