From: cov@codeaurora•org (Christopher Covington)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH] clocksource: arch_timer: Fix code to use physical timers when requested
Date: Thu, 28 Aug 2014 13:09:32 -0400 [thread overview]
Message-ID: <53FF624C.3090002@codeaurora.org> (raw)
In-Reply-To: <20140828093505.GC14650@leverpostej>
Hi Mark,
On 08/28/2014 05:35 AM, Mark Rutland wrote:
> On Thu, Aug 28, 2014 at 04:33:31AM +0100, Doug Anderson wrote:
>> Hi,
>>
>> On Wed, Aug 27, 2014 at 7:58 PM, Olof Johansson <olof@lixom•net> wrote:
>>> On Wed, Aug 27, 2014 at 5:56 PM, Stephen Boyd <sboyd@codeaurora•org> wrote:
>>>> On 08/27/14 15:33, Olof Johansson wrote:
>>>>> On Wed, Aug 27, 2014 at 3:26 PM, Stephen Boyd <sboyd@codeaurora•org> wrote:
>>>>>
>>>>>> Is there any reason why the virtual counter can't be read? Maybe we're
>>>>>> the hyp and we need to make sure we don't use the virtual timer so that
>>>>>> the guest can use it, but that doesn't have any effect on the usage of
>>>>>> the virtual counter for the clocksource.
>>>>>
>>>>> There are several cases where virtual is unusable -- in particular it
>>>>> might not have been configured properly (i.e. the phys/virt offset is
>>>>> at a bad value).
>>>>
>>>> Any specifics? It would be nice to say so in the commit text so that
>>>> others using such devices know they need this patch. I'm guessing the
>>>> firmware can't be fixed?
>>
>> Even if we could change things to use a virtual timer in some cases,
>> Sonny's patch still fixes a bug. The code as written right now makes
>> pretenses about supporting the physical timer, but it doesn't work.
>> That should be fixed.
>
> The code does support the physical timer. It does not support the
> physical counter (and makes no pretenses that it does).
I think if you could please explain the following code, that may help clear up
some of the confusion.
if (arch_timer_use_virtual) {
clk->irq = arch_timer_ppi[VIRT_PPI];
clk->set_mode = arch_timer_set_mode_virt;
clk->set_next_event = arch_timer_set_next_event_virt;
} else {
clk->irq = arch_timer_ppi[PHYS_SECURE_PPI];
clk->set_mode = arch_timer_set_mode_phys;
clk->set_next_event = arch_timer_set_next_event_phys;
}
http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/drivers/clocksource/arm_arch_timer.c#n272
Perhaps you mean to say the code does not support *non-secure access* to the
physical timer?
Thanks,
Christopher
--
Employee of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
hosted by the Linux Foundation.
next prev parent reply other threads:[~2014-08-28 17:09 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-08-27 21:03 [PATCH] clocksource: arch_timer: Fix code to use physical timers when requested Sonny Rao
2014-08-27 21:19 ` Olof Johansson
2014-08-27 21:27 ` Sonny Rao
2014-08-27 22:26 ` Stephen Boyd
2014-08-27 22:33 ` Olof Johansson
2014-08-28 0:56 ` Stephen Boyd
2014-08-28 2:58 ` Olof Johansson
2014-08-28 3:33 ` Doug Anderson
2014-08-28 9:35 ` Mark Rutland
2014-08-28 17:09 ` Christopher Covington [this message]
2014-08-28 18:04 ` Mark Rutland
2014-08-29 0:10 ` Sonny Rao
2014-08-29 10:04 ` Mark Rutland
2014-09-04 17:01 ` Sonny Rao
2014-09-04 17:47 ` Mark Rutland
2014-09-04 17:48 ` Lorenzo Pieralisi
2014-09-05 22:11 ` Doug Anderson
2014-09-08 13:54 ` Catalin Marinas
2014-09-10 17:17 ` Doug Anderson
2014-09-10 17:34 ` Will Deacon
2014-09-10 18:09 ` Doug Anderson
2014-09-10 18:46 ` Will Deacon
2014-09-10 19:50 ` Doug Anderson
2014-09-11 9:57 ` Will Deacon
2014-09-11 15:54 ` Doug Anderson
2014-09-10 14:58 ` Christopher Covington
2014-09-10 15:47 ` Catalin Marinas
2014-09-10 15:55 ` Mark Rutland
2014-09-10 16:39 ` Olof Johansson
2014-09-10 17:19 ` Doug Anderson
2014-08-28 9:23 ` Marc Zyngier
2014-09-10 17:27 ` Mark Rutland
2014-09-10 17:52 ` Doug Anderson
2014-09-10 18:05 ` Sonny Rao
2014-09-10 18:35 ` Doug Anderson
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