From mboxrd@z Thu Jan 1 00:00:00 1970 From: Scott Wood Date: Mon, 27 Jul 2015 21:17:42 -0500 Subject: [U-Boot] [PATCH v2 08/16] tegra: nand: fix read_byte required for proper onfi detection In-Reply-To: <67338B22-5874-48BF-982B-5E1D5F84A2BA@ziswiler.com> References: <1438027215.2993.304.camel@freescale.com> <67338B22-5874-48BF-982B-5E1D5F84A2BA@ziswiler.com> Message-ID: <1438049862.2993.322.camel@freescale.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de On Tue, 2015-07-28 at 04:05 +0200, Marcel Ziswiler wrote: > On 27 July 2015 22:00:15 CEST, Scott Wood wrote: > > On Tue, 2015-07-21 at 00:35 +0200, Marcel Ziswiler wrote: > > > From: Marcel Ziswiler > > > > > > Fix PIO read_byte() implementation not only used for the legacy READ > > ID > > > but also the PARAM command now required for proper ONFI detection. > > > > > > This fix is inspired by Lucas Stach's Linux Tegra NAND driver of > > late. > > > > Could you explain a bit more how this fixes issues with READ PARAM? > > I vaguely remember that those commands are special on 16-bit bus NAND (e.g. > always return 8-bit data regardless) and later Linux MTD fixed/changed the > way this is handled which in turn broke once U-Boot pulled that in. Which > as explained in my commit message this fixes by doing what Lucas does in > Linux (not mainline yet but getting there soon I hope). The more detail about this you can put in the changelog (describing what it is that Lucas does and how it helps), the better. > > > While at it also disable subpage writes. > > > > Why are these two changes combined? > > Well just because it's a one line fix but if required I can split that in a > separate patch as well. I think it should be separate, at least so it gets a separate changelog explaining why. -Scott