From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lucas Stach Subject: Re: [PATCH 2/4] clk: tegra: add EMC clock driver Date: Thu, 19 Dec 2013 12:43:28 +0100 Message-ID: <1387453408.1712.3.camel@tellur> References: <1387272400-4689-1-git-send-email-josephl@nvidia.com> <1387272400-4689-3-git-send-email-josephl@nvidia.com> <52B0D6FA.2060101@wwwdotorg.org> <1387359758.2576.38.camel@jlo-ubuntu-64.nvidia.com> <52B1E950.1040001@wwwdotorg.org> <20131219100557.GE17188@tbergstrom-lnx.Nvidia.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20131219100557.GE17188-Rysk9IDjsxmJz7etNGeUX8VPkgjIgRvpAL8bYrjMMd8@public.gmane.org> Sender: linux-tegra-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Peter De Schrijver Cc: Stephen Warren , Joseph Lo , Thierry Reding , "linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org" , Mike Turquette List-Id: linux-tegra@vger.kernel.org Am Donnerstag, den 19.12.2013, 12:05 +0200 schrieb Peter De Schrijver: [...] > > > funny tricks like running from IRAM since we can't access SDRAM during > > the clock change? If so, I'm not sure how having the EMC clock changing > > code is going to help your case (2) anyway, since we'll presumably have > > to code up a custom stub in assembly for the part of the code that runs > > from IRAM... > > > > There is no need for assembler or running from IRAM (at least from Tegra30 > onwards, I don't know about Tegra20). > Tegra20 doesn't need any IRAM trickery, the sequence is just: 1. set up EMC shadow registers for new clock frequency 2. change EMC divider in CAR module This was known working on Colibri T20 before the CCF change. Regards, Lucas From mboxrd@z Thu Jan 1 00:00:00 1970 From: dev@lynxeye.de (Lucas Stach) Date: Thu, 19 Dec 2013 12:43:28 +0100 Subject: [PATCH 2/4] clk: tegra: add EMC clock driver In-Reply-To: <20131219100557.GE17188@tbergstrom-lnx.Nvidia.com> References: <1387272400-4689-1-git-send-email-josephl@nvidia.com> <1387272400-4689-3-git-send-email-josephl@nvidia.com> <52B0D6FA.2060101@wwwdotorg.org> <1387359758.2576.38.camel@jlo-ubuntu-64.nvidia.com> <52B1E950.1040001@wwwdotorg.org> <20131219100557.GE17188@tbergstrom-lnx.Nvidia.com> Message-ID: <1387453408.1712.3.camel@tellur> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Am Donnerstag, den 19.12.2013, 12:05 +0200 schrieb Peter De Schrijver: [...] > > > funny tricks like running from IRAM since we can't access SDRAM during > > the clock change? If so, I'm not sure how having the EMC clock changing > > code is going to help your case (2) anyway, since we'll presumably have > > to code up a custom stub in assembly for the part of the code that runs > > from IRAM... > > > > There is no need for assembler or running from IRAM (at least from Tegra30 > onwards, I don't know about Tegra20). > Tegra20 doesn't need any IRAM trickery, the sequence is just: 1. set up EMC shadow registers for new clock frequency 2. change EMC divider in CAR module This was known working on Colibri T20 before the CCF change. Regards, Lucas