From mboxrd@z Thu Jan 1 00:00:00 1970 From: maxime.ripard@free-electrons.com (Maxime Ripard) Date: Fri, 27 Oct 2017 17:13:34 +0200 Subject: [PATCH 1/2] dt-bindings: add binding for A64 DE2 CCU with SRAM section In-Reply-To: References: <20171014122925.13220-1-icenowy@aosc.io> <20171016091136.b4rnckh2tfi26shx@flea.lan> <20171016120912.lxu7rikhffxsu5o4@flea.lan> Message-ID: <20171027151334.c3b7yqoiexgwopsf@flea> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Fri, Oct 27, 2017 at 10:33:29PM +0800, icenowy at aosc.io wrote: > ? 2017-10-16 20:09?Maxime Ripard ??? > > On Mon, Oct 16, 2017 at 05:41:10PM +0800, icenowy at aosc.io wrote: > > > ? 2017-10-16 17:11?Maxime Ripard ??? > > > > On Sat, Oct 14, 2017 at 08:29:24PM +0800, Icenowy Zheng wrote: > > > > > A64's Display Engine 2.0 needs a section of SRAM (SRAM C) to be > > > > > claimed. > > > > > > > > Why? > > > > > > Allwinner didn't document this, but if the SRAM is not claimed, the > > > DE2 MMIO zone is totally not accessible. > > > > Not accessible how? It generates an abort when you access it? It > > returns 0? > > > > > It seems that Allwinner uses the SRAM C in the DE2 internally. > > > > Then shouldn't it be tied to all the DE2 devices then? So mixers > > too. Either way, this should be mentionned in your commit logs. How > > you're fixing things is much less interesting than why you're doing > > them. You can tell how you're doing them from your code already. > > Yes I checked and when the SRAM is not claimed any part in DE2 memory > zone can't be accessed. Then all the nodes that depend on it should have it, and the bindings should be modified appropriately. Maxime -- Maxime Ripard, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 801 bytes Desc: not available URL: