From mboxrd@z Thu Jan 1 00:00:00 1970 From: Brian Norris Subject: Re: [PATCH v4 2/3] mtd: mtk-nor: mtk serial flash controller driver Date: Thu, 29 Oct 2015 09:03:31 -0700 Message-ID: <20151029160331.GA12954@localhost> References: <1444729160-26433-1-git-send-email-bayi.cheng@mediatek.com> <1444729160-26433-3-git-send-email-bayi.cheng@mediatek.com> <20151016073959.GB28158@localhost> <1445178035.4832.23.camel@mhfsdcap03> <20151029015237.GE13239@google.com> <1446089334.25711.10.camel@mhfsdcap03> <1446126991.25711.23.camel@mhfsdcap03> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <1446126991.25711.23.camel@mhfsdcap03> Sender: linux-kernel-owner@vger.kernel.org To: "bayi.cheng" Cc: David Woodhouse , Rob Herring , Pawel Moll , Mark Rutland , Ian Campbell , Kumar Gala , Matthias Brugger , Daniel Kurtz , Sascha Hauer , devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mtd@lists.infradead.org, srv_heupstream@mediatek.com, Marek Vasut List-Id: devicetree@vger.kernel.org On Thu, Oct 29, 2015 at 09:56:31PM +0800, bayi.cheng wrote: > On Thu, 2015-10-29 at 11:28 +0800, bayi.cheng wrote: > > On Wed, 2015-10-28 at 18:52 -0700, Brian Norris wrote: > > > On Sun, Oct 18, 2015 at 10:20:35PM +0800, bayi.cheng wrote: > > > > On Fri, 2015-10-16 at 00:39 -0700, Brian Norris wrote: > > > > > On Tue, Oct 13, 2015 at 05:39:19PM +0800, Bayi Cheng wrote: > > > > > > + /* mtk nor controller doesn't supoort SPINOR_OP_RDCR */ > > > > > > + switch (opcode) { > > > > > > + case SPINOR_OP_RDID: > > > > > > + /* read JEDEC ID need 4 bytes commands */ > > > > > > + ret = mt8173_nor_set_cmd(mt8173_nor, 0, 32, SPINOR_OP_RDID); > > > > > > + if (ret < 0) > > > > > > + return ret; > > > > > > + > > > > > > + /* mtk nor flash controller only support 3 bytes IDs */ > > > > > > > > > > Are you absolutely sure of this? That would be highly unfortunate, but > > > > > I also don't believe it's true. > > > > > > > > > Yes, for this issue I have asked our designer of nor flash controller, > > > > unfortunately, it is true, and I have tried to read more IDs, but our > > > > controller just accept 3 IDs from nor flash, and our next generation IC > > > > may solve this problem. > > > > > > How exactly did you try? Did you do what I suggested above? Are the > > > "shift registers" not all actually functional? > > > > > Hi Brian, For this problem, I have asked our nor controller designer to > > double confirm again, and he promise to do some simulation testes, On > > the other hand, I have got some Spansion nor flash which has 5 IDs, and > > after our designer make sure our controller can support 5 or 6 IDs, then > > I will rework a special platform with S25FL256SA. If we have any > > progress, I will inform you immediately! Thanks!! > > > Hi Brian, Thanks very much for your perseverance!! > Actually, You idea is correct, and our designer has completed some > simulation test on spansion nor flash witch has more than 3 IDs, and the > results has prove that we can support to read 5 IDs. I also double Awesome! > confirmed with spansion nor flash. The only pity is that our nor > controller can't support 6 IDs, we just support 5 IDs. That's not quite as awesome. But that's still much more workable than only 3 bytes. Perhaps we'll want a way to communicate that to the spi-nor layer, so it doesn't think it can match a full 6 bytes? > I will submit my changes to V6 version. Thanks again!! OK, but let me take another look at v5 and send you comments on that one first. Regards, Brian