Re: [PATCH] ARM: owl: smp: Drop owl_secondary_boot()

From: Gregory CLEMENT <gregory.clement@free-electrons.com>
To: Florian Fainelli <f.fainelli@gmail.com>
Cc: "Alexandre Belloni" <alexandre.belloni@free-electrons.com>,
	"Andreas Färber" <afaerber@suse.de>,
	linux-arm-kernel@lists.infradead.org, support@lemaker.org,
	张天益 <tyzhang@actions-semi.com>, "Arnd Bergmann" <arnd@arndb.de>,
	梅利 <harrymei@actions-semi.com>,
	linux-kernel@vger.kernel.org,
	"Thomas Liau" <thomas.liau@actions-semi.com>,
	"Russell King" <linux@armlinux.org.uk>,
	support@cubietech.com, lee@cubietech.com,
	张东风 <zhangdf@actions-semi.com>, 刘炜 <liuwei@actions-semi.com>,
	"Jason Cooper" <jason@lakedaemon.net>,
	"Andrew Lunn" <andrew@lunn.ch>,
	"Sebastian Hesselbarth" <sebastian.hesselbarth@gmail.com>,
	"Neil Armstrong" <narmstrong@baylibre.com>,
	"Nicolas Ferre" <nicolas.ferre@microchip.com>
Subject: Re: [PATCH] ARM: owl: smp: Drop owl_secondary_boot()
Date: Fri, 07 Jul 2017 09:34:18 +0200	[thread overview]
Message-ID: <87h8yod7k5.fsf@free-electrons.com> (raw)
In-Reply-To: <c6336df9-4f38-e636-383a-d0ad31658c65@gmail.com> (Florian Fainelli's message of "Thu, 6 Jul 2017 12:47:55 -0700")

Hi Florian,

 On jeu., juil. 06 2017, Florian Fainelli <f.fainelli@gmail.com> wrote:

> On 07/06/2017 10:38 AM, Alexandre Belloni wrote:
>> On 06/07/2017 at 19:17:28 +0200, Andreas Färber wrote:
>>> Am 05.07.2017 um 04:36 schrieb Florian Fainelli:
>>>> On July 4, 2017 4:32:18 PM PDT, "Andreas Färber" <afaerber@suse.de> wrote:
>>>>> Commit 18cfd9429d8a82c49add8f3ca9d366599bfcac45 ("ARM: owl: smp: Drop
>>>>> bogus holding pen") simplified the S500 SMP code by removing a loop for
>>>>> pen_release in owl_secondary_boot(). Since then it is only calling
>>>>> owl_v7_invalidate_l1() before branching to secondary_startup().
>>>>>
>>>>> The owl_v7_invalidate_l1() assembler function is superfluous, too.
>>>>> Therefore drop owl_secondary_boot() and use secondary_boot() directly.
>>>>>
>>>>> Cc: David Liu <liuwei@actions-semi.com>
>>>>> Signed-off-by: Andreas Färber <afaerber@suse.de>
>>>>> ---
>>>>
>>>>> -	writel(virt_to_phys(owl_secondary_startup),
>>>>> +	writel(virt_to_phys(secondary_startup),
>>>>> 	       timer_base_addr + OWL_CPU1_ADDR + (cpu - 1) * 4);
>>>>
>>>> This is a kernel symbol so please use __pa_symbol() here, also you
>>>> might want to build with CONFIG_DEBUG_VIRTUAL and see if you get
>>>> other warnings about using virt_to_phys() in the owl platform code
>>>> (I did not check if there are other uses)
>>>
>>> Thanks for the report. There are no other such uses in mach-actions, but
>>> git-grep'ing for virt_to_phys in arch/arm/mach-* I spot at least one
>>> other such usage in mach-oxnas:
>>>
>>> arch/arm/mach-oxnas/platsmp.c:
>>> writel(virt_to_phys(ox820_secondary_startup),
>>>
>>> as well as this in mach-mvebu:
>>>
>>> arch/arm/mach-mvebu/platsmp.c:  writel(virt_to_phys(boot_addr), base +
>>> MV98DX3236_CPU_RESUME_ADDR_REG);
>>>
>>> and these in mach-at91:
>>>
>>> arch/arm/mach-at91/pm.c:        pm_bu->canary = virt_to_phys(&canary);
>>> arch/arm/mach-at91/pm.c:        pm_bu->resume = virt_to_phys(cpu_resume);
>>>
>> 
>> They can probably use __pa_symbol() (I must admit I didn't know about
>> it before this email)
>
> This is fine, do you mind sending fixes for the at91 parts? Gregory, can
> you also fix the mv98dx3236 platform SMP code?

Yes sure, actually, for Armada XP we already use  __pa_symbol() but from
an other file that why I didn't pay attention on it.

Gregory

>
> Thanks!
> -- 
> Florian

-- 
Gregory Clement, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com