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From: Dmitry Osipenko <digetx@gmail.com>
To: Peter Crosthwaite <crosthwaitepeter@gmail.com>
Cc: Peter Maydell <peter.maydell@linaro.org>,
	qemu-arm <qemu-arm@nongnu.org>,
	QEMU Developers <qemu-devel@nongnu.org>
Subject: Re: [Qemu-arm] [PATCH v11 6/7] hw/ptimer: Legalize running with delta = load = 0 and abort on period = 0
Date: Sun, 24 Jan 2016 18:02:46 +0300	[thread overview]
Message-ID: <56A4E796.8050608@gmail.com> (raw)
In-Reply-To: <CAPokK=pOV7_uaumcbbJ0OZoSrYPz=iggCAG91U7Pcad6tKTOCg@mail.gmail.com>

24.01.2016 07:28, Peter Crosthwaite пишет:

[snip]

>>   /* Set counter frequency in Hz.  */
>>   void ptimer_set_freq(ptimer_state *s, uint32_t freq)
>>   {
>> +    g_assert(freq != 0);
>>       s->delta = ptimer_get_count(s);
>>       s->period = 1000000000ll / freq;
>>       s->period_frac = (1000000000ll << 32) / freq;

I noticed that this should be g_assert(freq != 0 && freq <= 1000000000), 
otherwise it possible to make period = 0 for the running timer when setting freq 
 > 1GHz, which doesn't make sense because we can't set period < 1ns.

Or maybe we should clamp period = max(1, period), freq = min(1000000000, freq) 
to "allow" higher timer freq's?

What do you think?

-- 
Dmitry

WARNING: multiple messages have this Message-ID (diff)
From: Dmitry Osipenko <digetx@gmail.com>
To: Peter Crosthwaite <crosthwaitepeter@gmail.com>
Cc: Peter Maydell <peter.maydell@linaro.org>,
	qemu-arm <qemu-arm@nongnu.org>,
	QEMU Developers <qemu-devel@nongnu.org>
Subject: Re: [Qemu-devel] [PATCH v11 6/7] hw/ptimer: Legalize running with delta = load = 0 and abort on period = 0
Date: Sun, 24 Jan 2016 18:02:46 +0300	[thread overview]
Message-ID: <56A4E796.8050608@gmail.com> (raw)
In-Reply-To: <CAPokK=pOV7_uaumcbbJ0OZoSrYPz=iggCAG91U7Pcad6tKTOCg@mail.gmail.com>

24.01.2016 07:28, Peter Crosthwaite пишет:

[snip]

>>   /* Set counter frequency in Hz.  */
>>   void ptimer_set_freq(ptimer_state *s, uint32_t freq)
>>   {
>> +    g_assert(freq != 0);
>>       s->delta = ptimer_get_count(s);
>>       s->period = 1000000000ll / freq;
>>       s->period_frac = (1000000000ll << 32) / freq;

I noticed that this should be g_assert(freq != 0 && freq <= 1000000000), 
otherwise it possible to make period = 0 for the running timer when setting freq 
 > 1GHz, which doesn't make sense because we can't set period < 1ns.

Or maybe we should clamp period = max(1, period), freq = min(1000000000, freq) 
to "allow" higher timer freq's?

What do you think?

-- 
Dmitry

  reply	other threads:[~2016-01-24 15:03 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-01-21 19:03 [Qemu-arm] [PATCH v11 0/7] PTimer fixes/features and ARM MPTimer conversion Dmitry Osipenko
2016-01-21 19:03 ` [Qemu-devel] " Dmitry Osipenko
2016-01-21 19:03 ` [Qemu-devel] [PATCH v11 1/7] hw/ptimer: Fix issues caused by the adjusted timer limit value Dmitry Osipenko
2016-01-21 19:03 ` [Qemu-devel] [PATCH v11 2/7] hw/ptimer: Perform counter wrap around if timer already expired Dmitry Osipenko
2016-01-24  5:29   ` Peter Crosthwaite
2016-01-25 19:43     ` Dmitry Osipenko
2016-01-21 19:03 ` [Qemu-devel] [PATCH v11 3/7] hw/ptimer: Update .delta on period/freq change Dmitry Osipenko
2016-01-21 19:03 ` [Qemu-devel] [PATCH v11 4/7] hw/ptimer: Support "on the fly" timer mode switch Dmitry Osipenko
2016-01-21 19:03 ` [Qemu-devel] [PATCH v11 5/7] hw/ptimer: Introduce ptimer_get_limit Dmitry Osipenko
2016-01-21 19:03 ` [Qemu-devel] [PATCH v11 6/7] hw/ptimer: Legalize running with delta = load = 0 and abort on period = 0 Dmitry Osipenko
2016-01-24  4:28   ` [Qemu-arm] " Peter Crosthwaite
2016-01-24  4:28     ` [Qemu-devel] " Peter Crosthwaite
2016-01-24 15:02     ` Dmitry Osipenko [this message]
2016-01-24 15:02       ` Dmitry Osipenko
2016-01-21 19:03 ` [Qemu-devel] [PATCH v11 7/7] arm_mptimer: Convert to use ptimer Dmitry Osipenko
2016-01-24  5:25   ` [Qemu-arm] " Peter Crosthwaite
2016-01-24  5:25     ` [Qemu-devel] " Peter Crosthwaite
2016-01-24 14:59     ` [Qemu-arm] " Dmitry Osipenko
2016-01-24 14:59       ` [Qemu-devel] " Dmitry Osipenko
2016-01-26 20:29       ` [Qemu-arm] " Dmitry Osipenko
2016-01-26 20:29         ` [Qemu-devel] " Dmitry Osipenko

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