linux-kernel - Re: [PATCH v3 1/7] firmware: coreboot: Let OF core populate platform device

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Message-ID: <20180809173158.GB129285@ban.mtv.corp.google.com>
Date:   Thu, 9 Aug 2018 10:31:59 -0700
From:   Brian Norris <briannorris@...omium.org>
To:     Stephen Boyd <swboyd@...omium.org>
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        linux-kernel@...r.kernel.org,
        Wei-Ning Huang <wnhuang@...omium.org>,
        Julius Werner <jwerner@...omium.org>,
        Samuel Holland <samuel@...lland.org>
Subject: Re: [PATCH v3 1/7] firmware: coreboot: Let OF core populate platform
 device

Hi,

On Thu, Aug 09, 2018 at 10:17:16AM -0700, Stephen Boyd wrote:
> Now that the /firmware/coreboot node in DT is populated by the core DT
> platform code with commit 3aa0582fdb82 ("of: platform: populate
> /firmware/ node from of_platform_default_populate_init()") we should and
> can remove the platform device creation here. Otherwise, the
> of_platform_device_create() call will fail, the coreboot of driver won't
> be registered, and this driver will never bind. At the same time, we
> should move this driver to use MODULE_DEVICE_TABLE so that module
> auto-load works properly when the coreboot device is auto-populated and
> we should drop the of_node handling that was presumably placed here to
> hold a reference to the DT node created during module init that no
> longer happens.

Yep, the of_node_put() was to complement of_find_compatible_node() which
was originally done in probe(), and then of_find_node_by_path() in
__init when it was upstreamed, and now it's no longer needed.

> 
> Cc: Wei-Ning Huang <wnhuang@...omium.org>
> Cc: Julius Werner <jwerner@...omium.org>
> Cc: Brian Norris <briannorris@...omium.org>
> Cc: Samuel Holland <samuel@...lland.org>
> Reviewed-by: Sudeep Holla <Sudeep.Holla@....com>
> Fixes: 3aa0582fdb82 ("of: platform: populate /firmware/ node from of_platform_default_populate_init()")
> Signed-off-by: Stephen Boyd <swboyd@...omium.org>
> ---
>  drivers/firmware/google/coreboot_table-of.c | 28 +++------------------
>  1 file changed, 3 insertions(+), 25 deletions(-)

Change looks good:

Reviewed-by: Brian Norris <briannorris@...omium.org>

Thanks!

Now to go figure out how a simple bugfix managed to blow up into a
7-patch series... If this goes on any longer, patch 1 should probably go
by itself, to fix the regression.

Brian

> diff --git a/drivers/firmware/google/coreboot_table-of.c b/drivers/firmware/google/coreboot_table-of.c
> index f15bf404c579..9b90c0fa4a0b 100644
> --- a/drivers/firmware/google/coreboot_table-of.c
> +++ b/drivers/firmware/google/coreboot_table-of.c
> @@ -19,7 +19,6 @@
>  #include <linux/io.h>
>  #include <linux/module.h>
>  #include <linux/of_address.h>
> -#include <linux/of_platform.h>
>  #include <linux/platform_device.h>
>  
>  #include "coreboot_table.h"
> @@ -30,7 +29,6 @@ static int coreboot_table_of_probe(struct platform_device *pdev)
>  	void __iomem *ptr;
>  
>  	ptr = of_iomap(fw_dn, 0);
> -	of_node_put(fw_dn);
>  	if (!ptr)
>  		return -ENOMEM;
>  
> @@ -44,8 +42,9 @@ static int coreboot_table_of_remove(struct platform_device *pdev)
>  
>  static const struct of_device_id coreboot_of_match[] = {
>  	{ .compatible = "coreboot" },
> -	{},
> +	{}
>  };
> +MODULE_DEVICE_TABLE(of, coreboot_of_match);
>  
>  static struct platform_driver coreboot_table_of_driver = {
>  	.probe = coreboot_table_of_probe,
> @@ -55,28 +54,7 @@ static struct platform_driver coreboot_table_of_driver = {
>  		.of_match_table = coreboot_of_match,
>  	},
>  };
> -
> -static int __init platform_coreboot_table_of_init(void)
> -{
> -	struct platform_device *pdev;
> -	struct device_node *of_node;
> -
> -	/* Limit device creation to the presence of /firmware/coreboot node */
> -	of_node = of_find_node_by_path("/firmware/coreboot");
> -	if (!of_node)
> -		return -ENODEV;
> -
> -	if (!of_match_node(coreboot_of_match, of_node))
> -		return -ENODEV;
> -
> -	pdev = of_platform_device_create(of_node, "coreboot_table_of", NULL);
> -	if (!pdev)
> -		return -ENODEV;
> -
> -	return platform_driver_register(&coreboot_table_of_driver);
> -}
> -
> -module_init(platform_coreboot_table_of_init);
> +module_platform_driver(coreboot_table_of_driver);
>  
>  MODULE_AUTHOR("Google, Inc.");
>  MODULE_LICENSE("GPL");
> -- 
> Sent by a computer through tubes
>