-----Original Message----- From: Marek Vasut [mailto:marex@denx.de] Sent: 2022年1月29日 1:37 To: Jaehoon Chung jh80.chung@samsung.com; u-boot@lists.denx.de Cc: sbabic@denx.de; Bough Chen haibo.chen@nxp.com; Igor Opaniuk igor.opaniuk@foundries.io; Peng Fan peng.fan@nxp.com Subject: Re: [PATCH] Revert "mmc: fsl_esdhc_imx: add wait_dat0() support"
On 1/28/22 08:30, Jaehoon Chung wrote:
Hi Marek,
Hi,
On 1/28/22 12:40, Marek Vasut wrote:
This reverts commit b5874b552ffa09bc1dc5dec6b5dd376c62dab45d.
It seems the iMX8MM SDHC controller always reports DAT0 line status as zero after voltage switch at the end of mmc_switch_voltage(), even if it is supposed to be high and scope confirms the DAT0 is high. Reverting this patch makes SDR104 work on iMX8MM, however, it is not clear why the DAT0 status is not correctly reported by the controller.
I didn't have an imx8mm board, so I wonder that other boards which is using
fsl_esdhci_imx driver have same problem.
I have multiple 8mm, just not the 8mm-evk.
I'm not sure...I remember that some controller doesn't support a busy signal. In kernel driver, also doesn't report correct status?
Kernel doesn't use this DAT0 readback, that's why it works in kernel.
U-Boot has been augmented with this DAT0 readback some time ago, I just noticed it on an 8mm board recently that it doesn't really work. There is also no errata.
I think it would be good to have NXP check this.
Hi,
The issue you meet should be related to one patch that was revert recently, refer to Commit f132aab40327 " Revert "mmc: fsl_esdhc_imx: use VENDORSPEC_FRC_SDCLK_ON to control card clock output""
The issue you meet seems the same as what I mentioned in my original commit log, I paste in the end. Revert this patch because we did find this patch has some side effect, like enlarge the whole boot up time about 20s. If you will, you can add back this patch on your side, and test it. I will send one new patch this week, to fix issue and avoid side effect.
Best Regards Haibo Chen
commit 63756575b42b8b4fb3f59cbbf0cedf03331bc2d2 Author: Haibo Chen haibo.chen@nxp.com Date: Wed Mar 3 17:05:46 2021 +0800
mmc: fsl_esdhc_imx: use VENDORSPEC_FRC_SDCLK_ON to control card clock output
For FSL_USDHC, it do not implement VENDORSPEC_CKEN/PEREN/HCKEN/IPGEN, these are reserved bits. Instead, use VENDORSPEC_FRC_SDCLK_ON to gate on/off the card clock output.
After commit b5874b552ffa ("mmc: fsl_esdhc_imx: add wait_dat0() support"), we meet SD3.0 card can't work at UHS mode, mmc_switch_voltage() fail because the second mmc_wait_dat0 return -ETIMEDOUT. According to SD spec, during voltage switch, need to gate off/on the card clock. If not set the FRC_SDCLK_ON, after CMD11, hardware will gate off the card clock automatically, so card do not detect the clock off/on behavior, so will draw the data0 line low until next command.
Fixes: b5874b552ffa ("mmc: fsl_esdhc_imx: add wait_dat0() support") Tested-by: Tim Harvey tharvey@gateworks.com Signed-off-by: Haibo Chen haibo.chen@nxp.com