linux-kernel - Re: [PATCH] drivers: Let several drivers depends on HAS_IOMEM for 'devm_ioremap

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Message-ID: <20140717083756.GA19686@ulmo>
Date:	Thu, 17 Jul 2014 10:37:57 +0200
From:	Thierry Reding <thierry.reding@...il.com>
To:	Chen Gang <gang.chen.5i5j@...il.com>
Cc:	Guenter Roeck <linux@...ck-us.net>,
	Richard Weinberger <richard@....at>,
	Lars-Peter Clausen <lars@...afoo.de>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	dmitry.torokhov@...il.com, linux-iio@...r.kernel.org,
	Benjamin Herrenschmidt <benh@...nel.crashing.org>, teg@...m.no,
	Lennox Wu <lennox.wu@...il.com>, Marek Vasut <marex@...x.de>,
	Liqin Chen <liqin.linux@...il.com>, msalter@...hat.com,
	linux-pwm@...r.kernel.org, devel@...verdev.osuosl.org,
	linux-watchdog@...r.kernel.org, linux-input@...r.kernel.org,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	knaack.h@....de, Martin Schwidefsky <schwidefsky@...ibm.com>,
	Mischa.Jonker@...opsys.com, jic23@...nel.org, arnd@...db.de,
	Geert Uytterhoeven <geert@...ux-m68k.org>
Subject: Re: [PATCH] drivers: Let several drivers depends on HAS_IOMEM for
 'devm_ioremap_resource'

On Thu, Jul 17, 2014 at 09:27:58AM +0800, Chen Gang wrote:
[...]
> diff --git a/include/linux/device.h b/include/linux/device.h
> index c2421e0..a7500c3 100644
> --- a/include/linux/device.h
> +++ b/include/linux/device.h
> @@ -630,7 +630,16 @@ extern unsigned long devm_get_free_pages(struct device *dev,
>  					 gfp_t gfp_mask, unsigned int order);
>  extern void devm_free_pages(struct device *dev, unsigned long addr);
>  
> +#ifdef CONFIG_HAS_IOMEM
>  void __iomem *devm_ioremap_resource(struct device *dev, struct resource *res);
> +#elif defined(CONFIG_COMPILE_TEST)
> +static inline void __iomem *devm_ioremap_resource(struct device *dev,
> +						struct resource *res)
> +{
> +	pr_warn("no hardware io memory, only for COMPILE_TEST\n");

Maybe: "Hardware doesn't support memory-mapped I/O"? I'm not sure if
it's useful to include the reference to COMPILE_TEST, especially since
the #elif will be dropped in favour of a simple #else.

> +	return (__force void __iomem *)ERR_PTR(-ENXIO);

There's apparently an IOMEM_ERR_PTR() for this nowadays...

> +}
> +#endif /* CONFIG_HAS_IOMEM || CONFIG_COMPILE_TEST */
>  
>  /* allows to add/remove a custom action to devres stack */
>  int devm_add_action(struct device *dev, void (*action)(void *), void *data);
> diff --git a/include/linux/io.h b/include/linux/io.h
> index b76e6e5..59128aa 100644
> --- a/include/linux/io.h
> +++ b/include/linux/io.h
> @@ -58,14 +58,42 @@ static inline void devm_ioport_unmap(struct device *dev, void __iomem *addr)
>  }
>  #endif
>  
> +#ifdef CONFIG_HAS_IOMEM
> +
>  void __iomem *devm_ioremap(struct device *dev, resource_size_t offset,
>  			    unsigned long size);
>  void __iomem *devm_ioremap_nocache(struct device *dev, resource_size_t offset,
>  				    unsigned long size);
>  void devm_iounmap(struct device *dev, void __iomem *addr);
> +void devm_ioremap_release(struct device *dev, void *res);
> +
> +#elif defined(CONFIG_COMPILE_TEST)
> +
> +static inline void __iomem *devm_ioremap(struct device *dev,
> +				resource_size_t offset, unsigned long size)

For consistency with other functions above, please keep arguments on
subsequent lines aligned with the first argument on the first line, like
so:

static inline void __iomem *devm_ioremap(struct device *dev,
					 resource_size_t offset,
					 unsigned long size)

> +{
> +	pr_warn("no hardware io memory, only for COMPILE_TEST\n");
> +	return NULL;
> +}
> +static inline void __iomem *devm_ioremap_nocache(struct device *dev,
> +				resource_size_t offset, unsigned long size)
> +{
> +	pr_warn("no hardware io memory, only for COMPILE_TEST\n");
> +	return NULL;
> +}

Perhaps this should call devm_ioremap() so we don't have to repeat the
same error message? Or maybe make it:

	#define devm_ioremap_nocache devm_ioremap

?

Thierry

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