From mboxrd@z Thu Jan 1 00:00:00 1970 From: Guillaume Gardet Date: Mon, 9 Apr 2018 16:03:28 +0200 Subject: [U-Boot] [BUG] snow: mmc: SD card access broken: unable to select a mode In-Reply-To: References: Message-ID: <4e4aff80-c077-650c-aec3-ce763b9f2bc7@free.fr> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit To: u-boot@lists.denx.de Le 09/04/2018 à 15:58, Jean-Jacques Hiblot a écrit : > > > On 09/04/2018 14:02, Guillaume Gardet wrote: >> Hi Jaehoon, >> >> There are problems with SD card access on Samsung Chromebook (snow) with latest master (and also 2018.05-rc1 and 2018.03). >> >> eMMC is ok, but SD card access leads to 'unable to select a mode' problem. If I disable HS mode, I can access the SD card without problem: >> ******************************************************************************** >> diff --git a/drivers/mmc/dw_mmc.c b/drivers/mmc/dw_mmc.c >> index 23f642980bf..28f4fa0f213 100644 >> --- a/drivers/mmc/dw_mmc.c >> +++ b/drivers/mmc/dw_mmc.c >> @@ -508,7 +508,8 @@ void dwmci_setup_cfg(struct mmc_config *cfg, struct dwmci_host *host, >>          cfg->host_caps |= MMC_MODE_4BIT; >>          cfg->host_caps &= ~MMC_MODE_8BIT; >>      } >> -    cfg->host_caps |= MMC_MODE_HS | MMC_MODE_HS_52MHz; >> +    /* Temp workaround for Chromebook snow to avoid the 'unable to select a mode' error */ >> +//     cfg->host_caps |= MMC_MODE_HS | MMC_MODE_HS_52MHz; >> >>      cfg->b_max = CONFIG_SYS_MMC_MAX_BLK_COUNT; >>  } >> ******************************************************************************** >> >> Once we try to select HS mode, all access to SD card result in failure, even when trying to setup a lower frequency mode, including SD legacy at 25 MHz. >> >> Any idea what is going? Maybe you have fixes pending? > > Can try with MMC_MODE_HS | MMC_MODE_HS_52MHz but with a lower max-frequency (<25MHz) ? It would be interesting to know if it could come from a frequency limitation. I already tried to change SD_HS freq (in mmc_mode2freq) from 50000000 to 25000000 with no difference. > Is there some pad configuration to do when using higher frequency? I do not think so. Guillaume > > JJ > >> >> >> Guillaume >> >> >> > >