From mboxrd@z Thu Jan 1 00:00:00 1970 From: Timur Tabi Date: Thu, 09 Nov 2006 15:23:46 -0600 Subject: [U-Boot-Users] flat tree clock setting In-Reply-To: <4553652A.1040606@freescale.com> References: <4553605D.5070205@freescale.com> <4553652A.1040606@freescale.com> Message-ID: <45539C62.6050900@freescale.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de Scott Wood wrote: > Are there any boards on which OF_TBCLK is (properly) set to something > other than what get_tbclk() returns (ignoring the difference in > rounding)? A search of the source code shows this: File /temp/u-boot-83xx/include/configs/MPC8349EMDS.h 332 2:#define OF_TBCLK (bd->bi_busfreq / 4) File /temp/u-boot-83xx/include/configs/MPC8349ITX.h 395 2:#define OF_TBCLK (bd->bi_busfreq / 4) File /temp/u-boot-83xx/include/configs/MPC8360EMDS.h 327 2:#define OF_TBCLK (bd->bi_busfreq / 4) File /temp/u-boot-83xx/include/configs/MPC8540ADS.h 309 2:#define OF_TBCLK (bd->bi_busfreq / 8) File /temp/u-boot-83xx/include/configs/MPC8541CDS.h 320 2:#define OF_TBCLK (bd->bi_busfreq / 8) File /temp/u-boot-83xx/include/configs/MPC8548CDS.h 326 2:#define OF_TBCLK (bd->bi_busfreq / 8) File /temp/u-boot-83xx/include/configs/MPC8555CDS.h 320 2:#define OF_TBCLK (bd->bi_busfreq / 8) File /temp/u-boot-83xx/include/configs/MPC8560ADS.h 302 2:#define OF_TBCLK (bd->bi_busfreq / 8) File /temp/u-boot-83xx/include/configs/MPC8641HPCN.h 269 2:#define OF_TBCLK (bd->bi_busfreq / 4) File /temp/u-boot-83xx/include/configs/stxxtc.h 587 2:#define OF_TBCLK (MPC8XX_HZ / 16) Let's ignore the stxxtc for now, whatever that is. On the 83xx, get_tbclk() returns "(gd->bus_clk + 3L) / 4L". On 85xx and 86xx, it does this: get_sys_info(&sys_info); return ((sys_info.freqSystemBus + 7L) / 8L); sys_info.freqSystemBus can be any number of things (see get_sys_info). Well, it looks like they COULD always contain the same value. > I don't see any, nor can I think of a reason why such a > difference should ever exist. Perhaps OF_TBCLK should just be removed? I think it's safe to say that *something* is redundant here, but I don't know yet what. My vote would be for OF_TBCLK, though, if that works. The only thing I know for sure is that all of this clock stuff is making me cuckoo. -- Timur Tabi Linux Kernel Developer @ Freescale