From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matthias Kaehlcke Date: Tue, 23 Feb 2010 23:44:02 +0100 Subject: [U-Boot] [PATCH 2/2] ep93xx: Refactoring of timer code In-Reply-To: <20100223222342.7BCDDE8CCE0@gemini.denx.de> References: <7ee75976e78e2f82b4163fe1ff4233a850d4393c.1266962256.git.matthias@kaehlcke.net> <20100223220421.GK20201@darwin> <20100223222342.7BCDDE8CCE0@gemini.denx.de> Message-ID: <20100223224402.GO20201@darwin> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de Hi Wolfgang, El Tue, Feb 23, 2010 at 11:23:42PM +0100 Wolfgang Denk ha dit: > In message <20100223220421.GK20201@darwin> you wrote: > > ep93xx: Refactoring of the timer code, including the following changes > ... > > +#define TIMER_FREQ 508469 > > +#define CLK_TICKS_PER_SYS_TICK (TIMER_FREQ / CONFIG_SYS_HZ) > ... > > + ticks *= (CLK_TICKS_PER_SYS_TICK * CONFIG_SYS_HZ); > ... > > + ticks = usecs * CLK_TICKS_PER_SYS_TICK * CONFIG_SYS_HZ; > > Why don't you use > > ticks *= TIMER_FREQ; > resp. > ticks = usecs * TIMER_FREQ; > > The combination of " / CONFIG_SYS_HZ * CONFIG_SYS_HZ" is just a bad > NO-OP (with rounding errors). you certainly have a point, i'm going to change this as you proposed > Hm... re-reading the optimized code makes me wonder if the variable > really should be called "ticks" - looks more as a frequency to me? here i disagree, the function returns the number of ticks that pass in a certain number of microseconds, so i think 'ticks' is an appropiate name thanks for your review! -- Matthias Kaehlcke Embedded Linux Developer Barcelona I cannot say whether things will get better if we change, what I can say is they must change if they are to get better (Georg Christoph Lichtenberg) .''`. using free software / Debian GNU/Linux | http://debian.org : :' : `. `'` gpg --keyserver pgp.mit.edu --recv-keys 47D8E5D4 `-