[U-Boot] [PATCH] mmc: Downgrade SD/MMC from UHS/HS200/HS400 modes before boot

[Marek Vasut]

On 5/2/19 12:24 PM, Faiz Abbas wrote:
> Hi Marek,
> 
> On 02/05/19 3:39 PM, Marek Vasut wrote:
>> On 5/2/19 9:57 AM, Faiz Abbas wrote:
>>> Hi,
>>
>> Hi,
>>
>>> On 14/02/19 6:56 PM, Marek Vasut wrote:
>>>> Older kernel versions or systems which do not connect eMMC reset line
>>>> properly may not be able to handle situations where either the eMMC
>>>> is left in HS200/HS400 mode or SD card in UHS modes by the bootloader
>>>> and may misbehave. Downgrade the eMMC to HS/HS52 mode and/or SD card
>>>> to non-UHS mode before booting the kernel to allow such older kernels
>>>> to work with modern U-Boot.
>>>
>>> This broke boot on all dra7xx devices. The fallback to DDR52 doesn't go
>>> through and all following commands timeout.
>>>
>>> Log:
>>>
>>> U-Boot 2019.04-rc4-00018-ga00d15757d (Mar 20 2019 - 17:25:22 +0200)
>>>
>>> CPU  : DRA752-GP ES2.0
>>> Model: TI DRA742
>>> Board: DRA74x EVM REV H.0
>>> DRAM:  4 GiB
>>> MMC:   OMAP SD/MMC: 0, OMAP SD/MMC: 1
>>> Loading Environment from FAT... *** Warning - bad CRC, using default
>>> environment
>>>
>>> Loading Environment from MMC... OK
>>> Net:   eth0: ethernet at 48484000
>>> Hit any key to stop autoboot:  0
>>> =>
>>> => boot
>>> Booting from network ...
>>> link up on port 0, speed 1000, full duplex
>>> BOOTP broadcast 1
>>> DHCP client bound to address 192.168.1.52 (246 ms)
>>> link up on port 0, speed 1000, full duplex
>>> Using ethernet at 48484000 device
>>> TFTP from server 192.168.1.36; our IP address is 192.168.1.52
>>> Filename 'zImage'.
>>> Load address: 0x87000000
>>> Loading: #################################################################
>>>          #################################################################
>>>          #################################################################
>>>          #################################################################
>>>          #################################################################
>>>          #################################################################
>>>          #################################################################
>>>          #################################################################
>>>          #################################################################
>>>          #################################################################
>>>          #############################################
>>>          3.3 MiB/s
>>> done
>>> Bytes transferred = 3556144 (364330 hex)
>>> link up on port 0, speed 1000, full duplex
>>> Using ethernet at 48484000 device
>>> TFTP from server 192.168.1.36; our IP address is 192.168.1.52
>>> Filename 'dra7-evm.dtb'.
>>> Load address: 0x88000000
>>> Loading: ######################
>>>          2.9 MiB/s
>>> done
>>> Bytes transferred = 108307 (1a713 hex)
>>> ## Flattened Device Tree blob at 88000000
>>>    Booting using the fdt blob at 0x88000000
>>>    Loading Device Tree to 8ffe2000, end 8ffff712 ... OK
>>> Using machid 0xfe6 from environment
>>>
>>> Starting kernel ...
>>>
>>> omap_hsmmc_send_cmd: timedout waiting on cmd inhibit to clear
>>> omap_hsmmc_send_cmd: timedout waiting on cmd inhibit to clear
>>> omap_hsmmc_send_cmd: timedout waiting on cmd inhibit to clear
>>> omap_hsmmc_send_cmd: timedout waiting on cmd inhibit to clear
>>> omap_hsmmc_send_cmd: timedout waiting on cmd inhibit to clear
>>> omap_hsmmc_send_cmd: timedout waiting on cmd inhibit to clear
>>> omap_hsmmc_send_cmd: timedout waiting on cmd inhibit to clear
>>> omap_hsmmc_send_cmd: timedout waiting on cmd inhibit to clear
>>> omap_hsmmc_send_cmd: timedout waiting on cmd inhibit to clear
>>> omap_hsmmc_send_cmd: timedout waiting on cmd inhibit to clear
>>
>> This seems to be a kernel bug ?
> 
> Kernel MMC hasn't even probed yet. This omap_hsmmc_send_cmd print is
> coming from drivers/mmc/omap_hsmmc.c:1066
> 
> Here's the Log with MMC_TRACE
> enabled:https://pastebin.ubuntu.com/p/M3W3DVjqn5/

Oh, could it be the clock were disabled at this point already ?
Or something along those lines. I don't have any omap board to test it
on, can you debug it ?

-- 
Best regards,
Marek Vasut