linux-kernel - Re: [PATCH 2/2] arm: omap_hwmod disable ick autoidling when a hwmod requires that

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <0976e09f-3f83-d1bc-5bd0-651e2f9c42d4@ti.com>
Date:   Thu, 8 Nov 2018 14:35:14 +0200
From:   Tero Kristo <t-kristo@...com>
To:     Andreas Kemnade <andreas@...nade.info>
CC:     <mturquette@...libre.com>, <sboyd@...nel.org>,
        <linux-omap@...r.kernel.org>, <linux-clk@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <bcousson@...libre.com>,
        <paul@...an.com>, <tony@...mide.com>,
        <letux-kernel@...nphoenux.org>
Subject: Re: [PATCH 2/2] arm: omap_hwmod disable ick autoidling when a hwmod
 requires that

On 08/11/2018 13:08, Andreas Kemnade wrote:
> Hi,
> 
> On Thu, 8 Nov 2018 12:26:08 +0200
> Tero Kristo <t-kristo@...com> wrote:
> 
>> On 04/10/2018 23:38, Andreas Kemnade wrote:
>>> Deny autoidle for hwmods with the OCPIF_SWSUP_IDLE flag,
>>> that makes hwmods working properly which cannot handle
>>> autoidle properly in lower power states.
>>> Affected is e. g. the omap_hdq.
>>> Since an ick might have mulitple users, autoidle is disabled
>>> when an individual user requires that rather than in
>>> _setup_iclk_autoidle. dss_ick is an example for that.
>>>
>>> Signed-off-by: Andreas Kemnade <andreas@...nade.info>
>>> ---
>>>    arch/arm/mach-omap2/omap_hwmod.c | 16 ++++++++++++----
>>>    1 file changed, 12 insertions(+), 4 deletions(-)
>>>
>>> diff --git a/arch/arm/mach-omap2/omap_hwmod.c b/arch/arm/mach-omap2/omap_hwmod.c
>>> index bb641e6c93d0..0078b0e1d242 100644
>>> --- a/arch/arm/mach-omap2/omap_hwmod.c
>>> +++ b/arch/arm/mach-omap2/omap_hwmod.c
>>> @@ -986,8 +986,10 @@ static int _enable_clocks(struct omap_hwmod *oh)
>>>    		clk_enable(oh->_clk);
>>>    
>>>    	list_for_each_entry(os, &oh->slave_ports, node) {
>>> -		if (os->_clk && (os->flags & OCPIF_SWSUP_IDLE))
>>> +		if (os->_clk && (os->flags & OCPIF_SWSUP_IDLE)) {
>>> +			omap2_clk_deny_idle(os->_clk);
>>
>> I think calling this unconditionally across all platforms / clock types
>> might cause problems. Checking kernel, am33xx seems to have one clock
>> with this flag that is not of omap2 type. Do we have any testing data
>> that this doesn't break things?
>>
> Somehow I have missed that am33xx clock. I have not tested it on that
> platform. Concerning am3xxx I have only a beaglebone block but it not
> am33xx I guess. So I have to recheck I guess.

Beaglebone black is am33xx based device, so you can use that for testing.

> But I think the intention of this flag was to control autoidle
> vs. sw-controlled idle according to...
> [...]
>>>    		if (os->flags & OCPIF_SWSUP_IDLE) {
>>> -			/* XXX omap_iclk_deny_idle(c); */
>>> +			/*
> this comment. So we need a if (clock_is_omap2()) or something like that
> or remove that flag from any other clocks?

You could add check within the omap2_clk_deny_idle / allow_idle calls 
themselves. You can check for presence of flag CLK_IS_BASIC, this is not 
set for omap clocks.

-Tero

> 
> Regards,
> Andreas
> 

--
Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki