From mboxrd@z Thu Jan 1 00:00:00 1970 From: Heiko Schocher Date: Fri, 13 Jan 2012 16:29:29 +0100 Subject: [U-Boot] [PATCH 1/2 V2] arm926: Flush the data cache before disabling it. In-Reply-To: <20120113082618.GA1557@Hardy> References: <1326133550-6706-1-git-send-email-urwithsughosh@gmail.com> <1326219136-1953-1-git-send-email-urwithsughosh@gmail.com> <20120113082618.GA1557@Hardy> Message-ID: <4F104DD9.2080308@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 Hello Sugosh, Sughosh Ganu wrote: > hi Christian, > > On Fri Jan 13, 2012 at 09:06:26AM +0100, Christian Riesch wrote: >> Hi Sughosh, >> I had a look at the patch and I tried to understand what's going on >> here (I must confess that I didn't know anything about this cache >> stuff). > > Ok, thanks for taking time off to understand this issue. > >> On Tue, Jan 10, 2012 at 7:12 PM, Sughosh Ganu wrote: >>> The current implementation invalidates the cache instead of flushing >>> it. This causes problems on platforms where the spl/u-boot is already >>> loaded to the RAM, with caches enabled by a first stage bootloader. Hmm.. how did u-boot work on such boards? How can u-boot work with D-Cache enabled, if u-boot is not initializing it? (And I think, on davinci SoC we have a none working uboot ethernet driver if d-cache is enabled too). There must be a page_table in DRAM for using D-Cache in U-Boot, if u-boot don't initialize it, it maybe overrides it ... or miss I something? Are you sure, the RBL enables the D-Cache on your board? Nevertheless, I think, we must disable the D-Cache here with "cleaning" it (as your patch did) instead only invalidating it, as current code did. bye, Heiko -- DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany