[PATCH] ARM: imx: use of_root to simplify code

[PATCH] ARM: imx: use of_root to simplify code

[Peng Fan]

From: Peng Fan <peng.fan@nxp.com>

start_kernel
     |->setup_arch
     |       |->unflatten_device_tree->of_root ready
     |
     |->do_initcalls
           |->customize_machine
                       |->init_machine
                              |->imx_soc_device_init

When imx_soc_device_init, of_root is ready, so we could directly use it.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
---

V1:
 Tested on i.MX7D-SDB

 arch/arm/mach-imx/cpu.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/arch/arm/mach-imx/cpu.c b/arch/arm/mach-imx/cpu.c
index 06f8d64b65af..77319b359070 100644
--- a/arch/arm/mach-imx/cpu.c
+++ b/arch/arm/mach-imx/cpu.c
@@ -88,7 +88,6 @@ struct device * __init imx_soc_device_init(void)
 	struct soc_device_attribute *soc_dev_attr;
 	const char *ocotp_compat = NULL;
 	struct soc_device *soc_dev;
-	struct device_node *root;
 	struct regmap *ocotp = NULL;
 	const char *soc_id;
 	u64 soc_uid = 0;
@@ -101,9 +100,7 @@ struct device * __init imx_soc_device_init(void)
 
 	soc_dev_attr->family = "Freescale i.MX";
 
-	root = of_find_node_by_path("/");
-	ret = of_property_read_string(root, "model", &soc_dev_attr->machine);
-	of_node_put(root);
+	ret = of_property_read_string(of_root, "model", &soc_dev_attr->machine);
 	if (ret)
 		goto free_soc;
 
-- 
2.16.4


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Re: [PATCH] ARM: imx: use of_root to simplify code

[Shawn Guo]

On Mon, Dec 30, 2019 at 09:03:51AM +0000, Peng Fan wrote:
> From: Peng Fan <peng.fan@nxp.com>
> 
> start_kernel
>      |->setup_arch
>      |       |->unflatten_device_tree->of_root ready
>      |
>      |->do_initcalls
>            |->customize_machine
>                        |->init_machine
>                               |->imx_soc_device_init
> 
> When imx_soc_device_init, of_root is ready, so we could directly use it.

IMO, of_root is something for OF core code, not really for platform.

Shawn

> 
> Signed-off-by: Peng Fan <peng.fan@nxp.com>
> ---
> 
> V1:
>  Tested on i.MX7D-SDB
> 
>  arch/arm/mach-imx/cpu.c | 5 +----
>  1 file changed, 1 insertion(+), 4 deletions(-)
> 
> diff --git a/arch/arm/mach-imx/cpu.c b/arch/arm/mach-imx/cpu.c
> index 06f8d64b65af..77319b359070 100644
> --- a/arch/arm/mach-imx/cpu.c
> +++ b/arch/arm/mach-imx/cpu.c
> @@ -88,7 +88,6 @@ struct device * __init imx_soc_device_init(void)
>  	struct soc_device_attribute *soc_dev_attr;
>  	const char *ocotp_compat = NULL;
>  	struct soc_device *soc_dev;
> -	struct device_node *root;
>  	struct regmap *ocotp = NULL;
>  	const char *soc_id;
>  	u64 soc_uid = 0;
> @@ -101,9 +100,7 @@ struct device * __init imx_soc_device_init(void)
>  
>  	soc_dev_attr->family = "Freescale i.MX";
>  
> -	root = of_find_node_by_path("/");
> -	ret = of_property_read_string(root, "model", &soc_dev_attr->machine);
> -	of_node_put(root);
> +	ret = of_property_read_string(of_root, "model", &soc_dev_attr->machine);
>  	if (ret)
>  		goto free_soc;
>  
> -- 
> 2.16.4
> 

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RE: [PATCH] ARM: imx: use of_root to simplify code

[Peng Fan]

+Rob

Hi Shawn,

> Subject: Re: [PATCH] ARM: imx: use of_root to simplify code
> 
> On Mon, Dec 30, 2019 at 09:03:51AM +0000, Peng Fan wrote:
> > From: Peng Fan <peng.fan@nxp.com>
> >
> > start_kernel
> >      |->setup_arch
> >      |       |->unflatten_device_tree->of_root ready
> >      |
> >      |->do_initcalls
> >            |->customize_machine
> >                        |->init_machine
> >                               |->imx_soc_device_init
> >
> > When imx_soc_device_init, of_root is ready, so we could directly use it.
> 
> IMO, of_root is something for OF core code, not really for platform.

From below link, I see powerpc and some driver use of_root directly.
https://elixir.bootlin.com/linux/v5.5-rc5/ident/of_root

of_root is exported as a symbol. Rob, could you please clarify whether
platform code could use of_root directly?

Thanks,
Peng.

> 
> Shawn
> 
> >
> > Signed-off-by: Peng Fan <peng.fan@nxp.com>
> > ---
> >
> > V1:
> >  Tested on i.MX7D-SDB
> >
> >  arch/arm/mach-imx/cpu.c | 5 +----
> >  1 file changed, 1 insertion(+), 4 deletions(-)
> >
> > diff --git a/arch/arm/mach-imx/cpu.c b/arch/arm/mach-imx/cpu.c index
> > 06f8d64b65af..77319b359070 100644
> > --- a/arch/arm/mach-imx/cpu.c
> > +++ b/arch/arm/mach-imx/cpu.c
> > @@ -88,7 +88,6 @@ struct device * __init imx_soc_device_init(void)
> >  	struct soc_device_attribute *soc_dev_attr;
> >  	const char *ocotp_compat = NULL;
> >  	struct soc_device *soc_dev;
> > -	struct device_node *root;
> >  	struct regmap *ocotp = NULL;
> >  	const char *soc_id;
> >  	u64 soc_uid = 0;
> > @@ -101,9 +100,7 @@ struct device * __init imx_soc_device_init(void)
> >
> >  	soc_dev_attr->family = "Freescale i.MX";
> >
> > -	root = of_find_node_by_path("/");
> > -	ret = of_property_read_string(root, "model", &soc_dev_attr->machine);
> > -	of_node_put(root);
> > +	ret = of_property_read_string(of_root, "model",
> > +&soc_dev_attr->machine);
> >  	if (ret)
> >  		goto free_soc;
> >
> > --
> > 2.16.4
> >

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