[PATCH v1 1/3] drivers: reset: Handle gracefully NULL pointers

From: Pratyush Yadav <p.yadav@ti.com>
To: u-boot@lists.denx.de
Subject: [PATCH v1 1/3] drivers: reset: Handle gracefully NULL pointers
Date: Wed, 27 May 2020 22:42:05 +0530	[thread overview]
Message-ID: <20200527171205.rjmzduwd6bfwhdtj@ti.com> (raw)
In-Reply-To: <CAPnjgZ1iL+wKYr7aBsSBBPEWsPzq0qha2cHrst1qP1Kjes7dXw@mail.gmail.com>

Hi Simon,

On 29/10/19 07:48PM, Simon Glass wrote:
> Hi Jean-Jacques,
> 
> On Mon, 30 Sep 2019 at 08:31, Jean-Jacques Hiblot <jjhiblot@ti.com> wrote:
> >
> > Prepare the way for a managed reset API by handling NULL pointers without
> > crashing nor failing.
> >
> > Signed-off-by: Jean-Jacques Hiblot <jjhiblot@ti.com>
> > ---
> >
> >  drivers/reset/reset-uclass.c | 30 +++++++++++++++++-------------
> >  1 file changed, 17 insertions(+), 13 deletions(-)
> 
> Same comment here about code size / Kconfig option.

A lot of the changes below are ternary operators. I'm not sure how to 
put them behind a Kconfig option to reduce code size. Do you want me to 
change the NULL check to a separate if() block to put behind an #ifdef?

One way of doing this is like in this patch [0]. The other would be to 
wrap individual if statements in #ifdef, which tends to hurt 
readability.

[0] https://patchwork.ozlabs.org/project/uboot/patch/20191001115130.18886-2-jjhiblot at ti.com/

> diff --git a/drivers/reset/reset-uclass.c b/drivers/reset/reset-uclass.c
> index ee1a423ffb..1cfcc8b367 100644
> --- a/drivers/reset/reset-uclass.c
> +++ b/drivers/reset/reset-uclass.c
> @@ -9,9 +9,12 @@ 
>  #include <reset.h>
>  #include <reset-uclass.h>
>  
> -static inline struct reset_ops *reset_dev_ops(struct udevice *dev)
> +struct reset_ops nop_reset_ops = {
> +};
> +
> +static inline struct reset_ops *reset_dev_ops(struct reset_ctl *r)
>  {
> -	return (struct reset_ops *)dev->driver->ops;
> +	return r ? (struct reset_ops *)r->dev->driver->ops : &nop_reset_ops;
>  }
>  
>  static int reset_of_xlate_default(struct reset_ctl *reset_ctl,
> @@ -50,9 +53,10 @@  static int reset_get_by_index_tail(int ret, ofnode node,
>  		debug("%s %d\n", ofnode_get_name(args->node), args->args[0]);
>  		return ret;
>  	}
> -	ops = reset_dev_ops(dev_reset);
>  
>  	reset_ctl->dev = dev_reset;
> +	ops = reset_dev_ops(reset_ctl);
> +
>  	if (ops->of_xlate)
>  		ret = ops->of_xlate(reset_ctl, args);
>  	else
> @@ -151,29 +155,29 @@  int reset_get_by_name(struct udevice *dev, const char *name,
>  
>  int reset_request(struct reset_ctl *reset_ctl)
>  {
> -	struct reset_ops *ops = reset_dev_ops(reset_ctl->dev);
> +	struct reset_ops *ops = reset_dev_ops(reset_ctl);
>  
>  	debug("%s(reset_ctl=%p)\n", __func__, reset_ctl);
>  
> -	return ops->request(reset_ctl);
> +	return ops->request ? ops->request(reset_ctl) : 0;
>  }
>  
>  int reset_free(struct reset_ctl *reset_ctl)
>  {
> -	struct reset_ops *ops = reset_dev_ops(reset_ctl->dev);
> +	struct reset_ops *ops = reset_dev_ops(reset_ctl);
>  
>  	debug("%s(reset_ctl=%p)\n", __func__, reset_ctl);
>  
> -	return ops->free(reset_ctl);
> +	return ops->free ? ops->free(reset_ctl) : 0;
>  }
>  
>  int reset_assert(struct reset_ctl *reset_ctl)
>  {
> -	struct reset_ops *ops = reset_dev_ops(reset_ctl->dev);
> +	struct reset_ops *ops = reset_dev_ops(reset_ctl);
>  
>  	debug("%s(reset_ctl=%p)\n", __func__, reset_ctl);
>  
> -	return ops->rst_assert(reset_ctl);
> +	return ops->rst_assert ? ops->rst_assert(reset_ctl) : 0;
>  }
>  
>  int reset_assert_bulk(struct reset_ctl_bulk *bulk)
> @@ -191,11 +195,11 @@  int reset_assert_bulk(struct reset_ctl_bulk *bulk)
>  
>  int reset_deassert(struct reset_ctl *reset_ctl)
>  {
> -	struct reset_ops *ops = reset_dev_ops(reset_ctl->dev);
> +	struct reset_ops *ops = reset_dev_ops(reset_ctl);
>  
>  	debug("%s(reset_ctl=%p)\n", __func__, reset_ctl);
>  
> -	return ops->rst_deassert(reset_ctl);
> +	return ops->rst_deassert ? ops->rst_deassert(reset_ctl) : 0;
>  }
>  
>  int reset_deassert_bulk(struct reset_ctl_bulk *bulk)
> @@ -213,11 +217,11 @@  int reset_deassert_bulk(struct reset_ctl_bulk *bulk)
>  
>  int reset_status(struct reset_ctl *reset_ctl)
>  {
> -	struct reset_ops *ops = reset_dev_ops(reset_ctl->dev);
> +	struct reset_ops *ops = reset_dev_ops(reset_ctl);
>  
>  	debug("%s(reset_ctl=%p)\n", __func__, reset_ctl);
>  
> -	return ops->rst_status(reset_ctl);
> +	return ops->rst_status ? ops->rst_status(reset_ctl) : 0;
>  }
>  
>  int reset_release_all(struct reset_ctl *reset_ctl, int count)

-- 
Regards,
Pratyush Yadav
Texas Instruments India