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

[Faiz Abbas]

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/

Thanks,
Faiz