From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tom Rini Date: Mon, 15 Apr 2019 08:14:17 -0400 Subject: [U-Boot] [PATCH 0/6] board: ti: am43xx: Enable hardware leveling In-Reply-To: <769ff12b-b671-031d-2dc9-7a50a23e7e7a@ti.com> References: <20190412063820.25924-1-j-keerthy@ti.com> <20190413130247.GJ4664@bill-the-cat> <5274f3fd-057e-04aa-5423-96ab6b304a28@ti.com> <20190415010520.GT4664@bill-the-cat> <9cc9a21f-4864-5867-4469-318e42a9600c@ti.com> <57c9af5e-43c9-aec7-d5d7-72a923b338b2@ti.com> <20190415112820.GU4664@bill-the-cat> <769ff12b-b671-031d-2dc9-7a50a23e7e7a@ti.com> Message-ID: <20190415121417.GV4664@bill-the-cat> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de On Mon, Apr 15, 2019 at 05:40:27PM +0530, Keerthy wrote: > > > On 15/04/19 4:58 PM, Tom Rini wrote: > >On Mon, Apr 15, 2019 at 12:22:22PM +0300, Tero Kristo wrote: > >>On 15/04/2019 11:56, Keerthy wrote: > >>> > >>> > >>>On 15/04/19 7:43 AM, keerthy wrote: > >>>> > >>>> > >>>>On 4/15/2019 6:35 AM, Tom Rini wrote: > >>>>>On Mon, Apr 15, 2019 at 06:19:31AM +0530, keerthy wrote: > >>>>>> > >>>>>> > >>>>>>On 4/13/2019 6:32 PM, Tom Rini wrote: > >>>>>>>On Fri, Apr 12, 2019 at 12:08:14PM +0530, Keerthy wrote: > >>>>>>> > >>>>>>>>The series adds the support for hardware leveling. This needs the > >>>>>>>>kernel to be patched with hardware leveling support and the > >>>>>>>>kernel support is already in linux-next: > >>>>>>>> > >>>>>>>>https://patchwork.kernel.org/project/linux-omap/list/?series=100273 > >>>>>>>> > >>>>>>>>Match recommended values from EMIF Tools app note: > >>>>>>>>http://www.ti.com/lit/an/sprac70/sprac70.pdf > >>>>>>> > >>>>>>>What happens if you boot an old kernel with this series applied? > >>>>>>>I'm a > >>>>>>>bit worried about applying something that breaks existing kernels, > >>>>>>>thanks! > >>>>>> > >>>>>>Hi Tom, > >>>>>> > >>>>>>Deep Sleep 0 feature will fail as the corresponding hardware leveling > >>>>>>patches will not be present. > >>>>> > >>>>>So to be clear, some new functionality will not work, but there is no > >>>>>functional regression? > >>>> > >>>>Okay i got your concern. Deep sleep 0 is currently working with software > >>>>leveling that will stop working with this patch series(hardware > >>>>leveling) applied on older kernels. EMIF tools application note > >>>>recommends hardware leveling over what existed previously. > >>>> > >>>>Hence i posted this series. Older kernels with this patch series Deep > >>>>sleep 0 feature will regress. > >>> > >>>Tom, > >>> > >>>We need hardware leveling as per EMIF document. So older kernels at best > >>>can backport the patches here: > >>> > >>>https://patchwork.kernel.org/patch/10882123/ > >>>https://patchwork.kernel.org/patch/10882127/ > >>> > >>>I do not see any other way to enable hardware leveling. > >>> > >>>Tero/Dave, > >>> > >>>Any concerns? > >> > >>Well, if we are to enable the feature, I can't see how we can avoid conflict > >>with older kernels. However, most of the time I would say people upgrade > >>their kernel before upgrading u-boot so this should be fine. If we are > >>really worried, we could maybe add the support to kernel first, wait some > >>time and merge the support to u-boot after that. > > > >I assume that as the patches are working their way through -next now, > >we're also talking about older vendor tree kernels being where this did > >work? > > > > older kernels will have to port the above patches else Deep Sleep 0 will > fail with newer u-boot with hardware leveling enabled. I assume they would > be using older u-boot as well? Yes, it sounds like there's reasonable support matrices here, thanks! -- Tom -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 819 bytes Desc: not available URL: