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From:   Michael Ellerman <mpe@ellerman.id.au>
To:     =?utf-8?B?546L5paH6JmO?= <wenhu.wang@vivo.com>
Cc:     Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Paul Mackerras <paulus@samba.org>,
        Allison Randal <allison@lohutok.net>,
        Richard Fontana <rfontana@redhat.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org,
        trivial@kernel.org, kernel@vivo.com,
        stable <stable@vger.kernel.org>
Subject: Re: [PATCH v3] powerpc/fsl-85xx: fix compile error
In-Reply-To: <AJUA5gAVCMaMlIkPsaTC0KqL.3.1584357605616.Hmail.wenhu.wang@vivo.com>
References: <AJUA5gAVCMaMlIkPsaTC0KqL.3.1584357605616.Hmail.wenhu.wang@vivo.com>
Date:   Tue, 17 Mar 2020 22:22:13 +1100
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=E7=8E=8B=E6=96=87=E8=99=8E <wenhu.wang@vivo.com> writes:
> From: Michael Ellerman <mpe@ellerman.id.au>
>  Date: 2020-03-16 17:41:12
> To:WANG Wenhu <wenhu.wang@vivo.com>,Benjamin Herrenschmidt <benh@kernel.c=
rashing.org>,Paul Mackerras <paulus@samba.org>,WANG Wenhu <wenhu.wang@vivo.=
com>,Allison Randal <allison@lohutok.net>,Richard Fontana <rfontana@redhat.=
com>,Greg Kroah-Hartman <gregkh@linuxfoundation.org>,Thomas Gleixner <tglx@=
linutronix.de>,linuxppc-dev@lists.ozlabs.org,linux-kernel@vger.kernel.org
>  cc: trivial@kernel.org,kernel@vivo.com,stable <stable@vger.kernel.org>
> Subject: Re: [PATCH v3] powerpc/fsl-85xx: fix compile error>WANG Wenhu <w=
enhu.wang@vivo.com> writes:
>>> Include "linux/of_address.h" to fix the compile error for
>>> mpc85xx_l2ctlr_of_probe() when compiling fsl_85xx_cache_sram.c.
>>>
>>>   CC      arch/powerpc/sysdev/fsl_85xx_l2ctlr.o
>>> arch/powerpc/sysdev/fsl_85xx_l2ctlr.c: In function =E2=80=98mpc85xx_l2c=
tlr_of_probe=E2=80=99:
>>> arch/powerpc/sysdev/fsl_85xx_l2ctlr.c:90:11: error: implicit declaratio=
n of function =E2=80=98of_iomap=E2=80=99; did you mean =E2=80=98pci_iomap=
=E2=80=99? [-Werror=3Dimplicit-function-declaration]
>>>   l2ctlr =3D of_iomap(dev->dev.of_node, 0);
>>>            ^~~~~~~~
>>>            pci_iomap
>>> arch/powerpc/sysdev/fsl_85xx_l2ctlr.c:90:9: error: assignment makes poi=
nter from integer without a cast [-Werror=3Dint-conversion]
>>>   l2ctlr =3D of_iomap(dev->dev.of_node, 0);
>>>          ^
>>> cc1: all warnings being treated as errors
>>> scripts/Makefile.build:267: recipe for target 'arch/powerpc/sysdev/fsl_=
85xx_l2ctlr.o' failed
>>> make[2]: *** [arch/powerpc/sysdev/fsl_85xx_l2ctlr.o] Error 1
>>>
>>> Fixes: commit 6db92cc9d07d ("powerpc/85xx: add cache-sram support")
>>
>>The syntax is:
>>
>>Fixes: 6db92cc9d07d ("powerpc/85xx: add cache-sram support")
>>
>>> Cc: stable <stable@vger.kernel.org>
>>
>>The commit above went into v2.6.37.
>>
>>So no one has noticed this bug since then, how? Or did something else
>>change to expose the problem?
>
> Actually a hard question to answer cause it also left me scratching for l=
ong.
> However, I can not find right or definite answer.

Oh, actually it's fairly straight forward, the code can't be built at
all in upstream because CONFIG_FSL_85XX_CACHE_SRAM is not selectable or
selected by anything.

You sent a patch previously to make it selectable, which Scott thought
was a bad idea.

So this whole file is dead code as far as I'm concerned, so patches for
it definitely do not need to go to stable.

If you want to add a user for it then please send a series doing that,
and this commit can be the first.

cheers