> -----Original Message----- > From: Trent Piepho [mailto:tpie...@impinj.com] > Sent: 2019年3月28日 4:43 > To: Peng Fan <peng....@nxp.com>; jh80.ch...@samsung.com; > sba...@denx.de > Cc: ma...@denx.de; kis...@ti.com; dl-linux-imx <linux-...@nxp.com>; > u-boot@lists.denx.de > Subject: Re: [U-Boot,V4,1/2] mmc: add HS400 support > > I didn't see HS400 working on my IMX7d, even thought it appears it should be > supported. > > The problem appears to be when this bit of code in fsl_esdhc.c, which dates to > a patch "mmc: fsl_esdhc: support SDR104 and HS200": > > static struct esdhc_soc_data usdhc_imx7d_data = { > .flags = ESDHC_FLAG_USDHC | ESDHC_FLAG_STD_TUNING > | ESDHC_FLAG_HAVE_CAP1 | > ESDHC_FLAG_HS200 > | ESDHC_FLAG_HS400, > .caps = UHS_CAPS | MMC_MODE_HS200 | > MMC_MODE_DDR_52MHz | > MMC_MODE_HS_52MHz | MMC_MODE_HS, }; > > Notice that MMC_MODE_HS400 isn't in the caps list. Once I add that uboot > will attempt HS400 and it appears to work correctly. > > I think maybe this patch should have added this to the caps? > > Alternatively, there is a property that can be added to the device tree, > mmc-hs400-1_8v, that will add this cap. But the code to parse those dt > properties, mmc_of_parse(), isn't used by the fsl_esdhc driver, which has its > own parsing code that doesn't know about mmc- hs400-1_8v. > > So maybe fsl-esdhc should use mmc_of_parse() and the appropriate iMX DTs > should add those properties? > > I think the DT method might be better, since it would allow the DT to not > list a > mode that doesn't work due to the the board. I.e., the iMX host supports > the mode, the eMMC supports the mode, but the board layout doesn't have > traces that can support it. Too long, not matched well enough, etc. It > doesn't seem like there's an nice way to remove a mode otherwise.
Yes. Parse device tree will be better. Regards, Peng. _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de https://lists.denx.de/listinfo/u-boot
