[U-Boot] [PATCH 4/7] mmc: rescan fails on empty slot

[Jaehoon Chung]

Hi Michael

Thanks for your explanation. :)

Regards,
Jaehoon Chung

Michael Jones wrote:
> Hi Jaehoon Chung,
> 
> On 07/19/2011 04:06 AM, Jaehoon Chung wrote:
>> Hi Michael.
>>
>> I have some question. there are some mmc_init().
>> But you are only checked there..
>> Did you have any special reason?
>>
>> Regards,
>> Jaehoon Chung
> 
> The purpose of my patch was to enable an if/else to detect whether there
> was a card in the slot. Among the available mmc commands, I thought 'mmc
> rescan' was the most logical to be able to use to detect whether a slot
> was empty or not.
> 
> Below is a survey of other places where a similar check could be done. I
> think that if a similar check is to be made in these cases, they could
> be in separate patch(es) from this one.
> 
> - 'mmc read/write': These commands should fail anyway if the slot were
> empty.
> - 'mmc part' prints "## Unknown partition table" if the slot is empty,
> although the command itself still returns successfully. I suppose the
> check could make sense here.
> - 'mmc dev': I thought there was perhaps a use case where it makes sense
> to switch to a mmc device which is currently empty. If that is not true,
> it would probably make sense to do the same check there.
> - 'mmcinfo': Currently this basically prints '0' for all the fields when
> the slot is empty. It probably would be more logical to print "device
> init failed" or similar instead.
> 
> -Michael
> 
>> Michael Jones wrote:
>>> Fail in 'mmc rescan' if mmc_init() returns error
>>>
>>> Signed-off-by: Michael Jones <michael.jones at matrix-vision.de>
>>> ---
>>>  common/cmd_mmc.c |    6 ++++--
>>>  1 files changed, 4 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/common/cmd_mmc.c b/common/cmd_mmc.c
>>> index 176646d..28918f6 100644
>>> --- a/common/cmd_mmc.c
>>> +++ b/common/cmd_mmc.c
>>> @@ -165,9 +165,11 @@ int do_mmcops(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
>>>  		}
>>>  
>>>  		mmc->has_init = 0;
>>> -		mmc_init(mmc);
>>>  
>>> -		return 0;
>>> +		if (mmc_init(mmc))
>>> +			return 1;
>>> +		else
>>> +			return 0;
>>>  	} else if (strncmp(argv[1], "part", 4) == 0) {
>>>  		block_dev_desc_t *mmc_dev;
>>>  		struct mmc *mmc = find_mmc_device(curr_device);
> 
> 
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