> -----Original Message----- > From: Adam Ford <aford...@gmail.com> > Sent: Saturday, December 5, 2020 4:01 PM > To: ZHIZHIKIN Andrey <andrey.zhizhi...@leica-geosystems.com> > Cc: u-boot@lists.denx.de; af...@beaconembedded.com > Subject: Re: [PATCH] imx8mm_beacon: Enable HS400 on MMC controller > > On Sat, Dec 5, 2020 at 8:54 AM ZHIZHIKIN Andrey <andrey.zhizhikin@leica- > geosystems.com> wrote: > > > > Hello Adam, > > > > > -----Original Message----- > > > From: U-Boot <u-boot-boun...@lists.denx.de> On Behalf Of Adam Ford > > > Sent: Saturday, December 5, 2020 2:00 AM > > > To: u-boot@lists.denx.de > > > Cc: af...@beaconembedded.com; Adam Ford <aford...@gmail.com> > > > Subject: [PATCH] imx8mm_beacon: Enable HS400 on MMC controller > > > > > > > > > The i.MX8MM is capable of HS400. Enable it in both U-Boot and SPL > > > for faster throughput. > > > > I'm not quite sure if those high-speed modes would be required to be > > enabled for SPL... > There are separate SPL flags, so we could leave them off. > > > > > Even though the support for those modes is provided in SPL build, > > there might be a little benefit of having it enabled as the only thing > > SPL would need to fetch from storage medias would be U-Boot itself, > > and the difference in access time between high speed modes enabled or > > disabled for this task is quite negligible. The downside there would rather > > be an > increase in SPL size to accommodate enabled code paths. > > > > I was contemplating myself to have those included, but decided to > > op-out from it as I could not justify the benefit of it. > > > > Do you see any particular use-case where it would be beneficial to > > enable those modes in SPL? If so - can you please share them, as if it > > would turn out to be beneficial - I might also turn them on in EVK configs. > > I turned them on because I could and it fit into SPL. In theory the impy > could be > deactivated for people who don't have the room. I didn't do any time > measurements so I don't know of the higher speed made it load u-boot any > faster since it takes a little more time to do the extra initialization, I > can see the > argument to leave them off.
OK, got it! Since you've introduced it for a specific derivative and you know that from the size perspective it fits - then I believe it is OK to have them enabled. > > Maybe it's best to default the configs to leave them off in SPL, and let > people > decide on what's best for their boards. For the Beacon board, I'll probably > leave it > on, but if SPL size constraints become an issue, I might turn them off later. For EVK configs I would leave SPL configs OFF. > > adam > > > > > > > > Signed-off-by: Adam Ford <aford...@gmail.com> > > > > > > diff --git a/configs/imx8mm_beacon_defconfig > > > b/configs/imx8mm_beacon_defconfig index c5d331f617..49d5453078 > > > 100644 > > > --- a/configs/imx8mm_beacon_defconfig > > > +++ b/configs/imx8mm_beacon_defconfig > > > @@ -70,6 +70,13 @@ CONFIG_DM_I2C=y > > > CONFIG_SYS_I2C_MXC=y > > > CONFIG_DM_MMC=y > > > CONFIG_SUPPORT_EMMC_BOOT=y > > > +CONFIG_MMC_IO_VOLTAGE=y > > > +CONFIG_SPL_MMC_IO_VOLTAGE=y > > > +CONFIG_MMC_UHS_SUPPORT=y > > > +CONFIG_SPL_MMC_UHS_SUPPORT=y > > > +CONFIG_MMC_HS400_ES_SUPPORT=y > > > +CONFIG_MMC_HS400_SUPPORT=y > > > +CONFIG_SPL_MMC_HS400_SUPPORT=y > > > CONFIG_FSL_USDHC=y > > > CONFIG_PHYLIB=y > > > CONFIG_PHY_ATHEROS=y > > > -- > > > 2.25.1 > > > > -- andrey -- andrey
