From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wolfgang Denk Date: Wed, 23 Sep 2020 14:48:18 +0200 Subject: [PATCH] powerpc: reduce number of WATCHDOG_RESET calls from flush_cache In-Reply-To: References: <20200604093039.26781-1-rasmus.villemoes@prevas.dk> <47d06069-e8d6-5351-cd90-4ba53c458719@denx.de> Message-ID: <3933429.1600865298@gemini.denx.de> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de Dear Rasmus, In message you wrote: > On 04/06/2020 12.31, Stefan Roese wrote: > > On 04.06.20 11:30, Rasmus Villemoes wrote: > >> Calling WATCHDOG_RESET for each and every cache line is overkill. > >> > >> In our case, the kernel image is a little over 7MB, and the almost > >> 500000 calls of WATCHDOG_RESET() adds about one second to the > >> boottime. > >> > >> I very highly doubt there's any real hardware where flushing 64K > >> from cache to memory takes more than a few milliseconds, so this > >> should be completely safe. Since it reduces the number of Maybe it is, maybe it is not. I remember boards where the watchdog trigger had to happen in pretty tight intervals, something like min 20, max 60 milliseconds. > >> +??????? if ((addr & (SZ_64K - 1)) == 0) In any case, please write readable code. The use of SZ_ here is not a good idea. Also, you might want to make the actual parameter configurable, so boards with specific timing requirements can adjust this as needed. Best regards, Wolfgang Denk -- DENX Software Engineering GmbH, Managing Director: Wolfgang Denk HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de Perfection is reached, not when there is no longer anything to add, but when there is no longer anything to take away. - Antoine de Saint-Exupery