Date:	Thu, 17 Jul 2014 09:27:58 +0800
From:	Chen Gang <gang.chen.5i5j@...il.com>
To:	Guenter Roeck <linux@...ck-us.net>,
	Richard Weinberger <richard@....at>
CC:	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,
	Thierry Reding <thierry.reding@...il.com>,
	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 07/15/2014 10:38 PM, Chen Gang wrote:
> On 07/15/2014 09:11 AM, Chen Gang wrote:
>>
>>
>> On 07/15/2014 08:53 AM, Guenter Roeck wrote:
>>> On 07/14/2014 05:34 PM, Chen Gang wrote:
>>>> On 07/14/2014 05:22 PM, Chen Gang wrote:
>>>>>
>>>>> 在 2014年7月14日，下午4:57，Richard Weinberger <richard@....at> 写道：
>>>>>
>>>>>> Am 14.07.2014 10:48, schrieb Lars-Peter Clausen:
>>>>>>> On 07/14/2014 10:31 AM, Richard Weinberger wrote:
>>>>>>>> Am 13.07.2014 22:17, schrieb Greg Kroah-Hartman:
>>>>>>>>> On Sun, Jul 13, 2014 at 09:33:38PM +0200, Richard Weinberger wrote:
>>>>>>>>>> Maybe we could add COMPILE_TEST to the version string too?
>>>>>>>>>> Just to detect such kernels fast in user bug reports...
>>>>>>>>>
>>>>>>>>> What kind of bug report are you going to get?
>>>>>>>>
>>>>>>>> User manages to enable CONFIG_FOO by selecting COMPILE_TEST and
>>>>>>>> complains that it does not work. :)
>>>>>>>
>>>>>>> These drivers are typically drivers for some SoC peripheral and the
>>>>>>> device will simply physically not exist on a platform that does not
>>>>>>> provide HAS_IOMEM. This is not really any
>>>>>>> different from making the driver selectable via COMPILE_TEST for
>>>>>>> any other platform. To hit the issue you'd have to instantiate a
>>>>>>> device driver instance for a device that
>>>>>>> physically does not exist. This will always result in a failure.
>>>>>>
>>>>>> Okay, you have convinced me. :)
>>>>>>
>>>>
>>>> After search the history patches, I found one related patch which made
>>>> by myself (when I am in Asianux):
>>>>
>>>>    "https://lkml.org/lkml/2013/7/1/641"
>>>>
>>>> For me, it is a long discussion, and forced many members have to join
>>>> in. Please help check again.
>>>>
>>>
>>> One thing you could try would be to return NULL (or where appropriate
>>> an error) in the #else case of CONFIG_HAS_IOMEM and CONFIG_HAS_IOPORT,
>>> ie dont take COMPILE_TEST into account at all. Obviously that means
>>> you won't be able to dump a warning message in the COMPILE_TEST
>>> case, but at least the code would compile. The rejection of above patch
>>> would make a good case for this approach.
>>>

For me, only let 'devm_io*map*' support COMPILE_TEST is OK, that can fix
all related issues:


[PATCH] lib: devres: Add dumy functions to support COMPILE_TEST when no IOMEM

For some architectures which no IOMEM, 'devres' will be skipped. But
many drivers may still want COMPILE_TEST, so let 'devres' support it.

The related error (with allmodconfig under score):

    MODPOST 1365 modules
  ERROR: "devm_ioremap_resource" [drivers/watchdog/tegra_wdt.ko] undefined!
  ERROR: "devm_ioremap_resource" [drivers/watchdog/of_xilinx_wdt.ko] undefined!
  ERROR: "devm_ioremap_resource" [drivers/staging/iio/adc/mxs-lradc.ko] undefined!
  ERROR: "devm_ioremap_resource" [drivers/pwm/pwm-clps711x.ko] undefined!
  ERROR: "devm_ioremap_resource" [drivers/input/serio/olpc_apsp.ko] undefined!
  ERROR: "devm_ioremap_resource" [drivers/input/serio/arc_ps2.ko] undefined!
  ERROR: "devm_ioremap_resource" [drivers/rtc/rtc-xgene.ko] undefined!
  ERROR: "devm_ioremap_resource" [drivers/rtc/rtc-stk17ta8.ko] undefined!
  ERROR: "devm_ioremap_resource" [drivers/rtc/rtc-ds1742.ko] undefined!
  ERROR: "devm_ioremap_resource" [drivers/rtc/rtc-ds1553.ko] undefined!
  ERROR: "devm_ioremap_resource" [drivers/rtc/rtc-ds1511.ko] undefined!
  ERROR: "devm_ioremap_resource" [drivers/rtc/rtc-ds1286.ko] undefined!
  ERROR: "devm_ioremap" [drivers/rtc/rtc-rp5c01.ko] undefined!
  ERROR: "devm_ioremap" [drivers/rtc/rtc-msm6242.ko] undefined!
  ERROR: "devm_ioremap" [drivers/rtc/rtc-m48t59.ko] undefined!
  ERROR: "devm_ioremap" [drivers/rtc/rtc-m48t35.ko] undefined!
  ERROR: "devm_ioremap" [drivers/rtc/rtc-bq4802.ko] undefined!


Signed-off-by: Chen Gang <gang.chen.5i5j@...il.com>
---
 include/linux/device.h |  9 +++++++++
 include/linux/io.h     | 30 +++++++++++++++++++++++++++++-
 2 files changed, 38 insertions(+), 1 deletion(-)

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");
+	return (__force void __iomem *)ERR_PTR(-ENXIO);
+}
+#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)
+{
+	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;
+}
+
+static inline void devm_iounmap(struct device *dev, void __iomem *addr)
+{
+}
+
+static inline void devm_ioremap_release(struct device *dev, void *res)
+{
+}
+
+#endif /* CONFIG_HAS_IOMEM || CONFIG_COMPILE_TEST */
+
 int check_signature(const volatile void __iomem *io_addr,
 			const unsigned char *signature, int length);
-void devm_ioremap_release(struct device *dev, void *res);
 
 /*
  * Some systems do not have legacy ISA devices.
-- 
1.9.2.459.g68773ac

>>
>> OK, thanks: at least, it can be improved.  But still welcome any other
>> opinions of another related members.
>>
> 
> If no reply within 3 days (2014-07-18), I shall try to send related
> patch for it within this week end (2014-07-20).
> 
> Thanks.
> 

-- 
Chen Gang

Open, share, and attitude like air, water, and life which God blessed
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