From: robert.jarzmik@free•fr (Robert Jarzmik)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH 1/4] pxa2xx/cpufreq: Simplify CPU frequency change asm
Date: Wed, 23 Jun 2010 21:00:19 +0200 [thread overview]
Message-ID: <87eifxa81o.fsf@free.fr> (raw)
In-Reply-To: <1276840135-5982-1-git-send-email-marek.vasut@gmail.com> (Marek Vasut's message of "Fri\, 18 Jun 2010 07\:48\:52 +0200")
Marek Vasut <marek.vasut@gmail•com> writes:
> This patch does the following changes to cpufreq-pxa2xx:
> 1) Simplifies the assembler code for frequency change
OK, but did you think over what the old code was doing ?
My guess is that all the jumps were there to trigger a load into the I-Cache
before playing with memory timings. Did you consider that your new assembly fits
fully into a cache line, and hence is protected from memory shutdown for the
frequency change period ?
If you thought this over, then I would suggest to put a comment into the code to
state that the assembly bit fits fully in one cache line. If not, I don't see
clearly the benefit of removing the jumps ("b 2f" and "b 1b").
And I didn't find the reference for the need of reading the MDREFR register
after the write. Would you give me a pointer in the pxa27x TRM please ?
Cheers.
--
Robert
next prev parent reply other threads:[~2010-06-23 19:00 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-06-18 5:48 [PATCH 1/4] pxa2xx/cpufreq: Simplify CPU frequency change asm Marek Vasut
2010-06-18 5:48 ` [PATCH 2/4] pxa2xx/cpufreq: Simplify DRI recomputation routine Marek Vasut
2010-06-22 18:33 ` Robert Jarzmik
2010-06-18 5:48 ` [PATCH 3/4] pxa2xx/cpufreq: Fix PCMCIA frequency scaling Marek Vasut
2010-06-23 17:49 ` Robert Jarzmik
2010-06-24 18:51 ` Marek Vasut
2010-06-24 19:12 ` Russell King - ARM Linux
2010-06-24 19:33 ` Marek Vasut
2010-06-24 19:46 ` Nicolas Pitre
2010-06-28 4:48 ` Eric Miao
2010-06-18 5:48 ` [PATCH 4/4] pxa2xx/pcmcia: Prepare for pxa320 Marek Vasut
2010-06-23 19:00 ` Robert Jarzmik [this message]
2010-06-24 3:17 ` [PATCH 1/4] pxa2xx/cpufreq: Simplify CPU frequency change asm Marek Vasut
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