shell cmd msdosfmt a NOOP (in 4.9.1) for SD/MMC

[Gene Smith]

Chris Johns wrote, On 01/23/2009 07:01 PM:
> Gene Smith wrote:
>> I tried the shell command msdosfmt again on my MMC and still nothing 
>> happens. I thought I had all my drivers working OK. It gets to the point 
>> in the format code where it wants to write a block to flash but the 
>> "write_entry" for the driver is NULL so nothing happens. However, no 
>> error is flagged so the shell still prints "formatting successful."
>>
>> The write_entry is the NULL entry for sd_card_disk_ops in spi-sd-card.c. 
>> When I change it from NULL and set it to sd_card_driver_write (a 
>> function in the same file that I had never seen called) msdosfmt 
>> attempts to do the write of the block with this function.
>>
>> However, it still fails inside sd_card_driver_write(). I think because 
>> the driver table "e" that it gets with the call to 
>> sd_card_driver_get_entry() is bad since the "major number" is 8 (a 2nd 
>> instance) instead of "major number" 9 (the first instance with the flash 
>> info set correctly). This kludge fixes it inside 4.9.1's 
>> sd_card_driver_write():
>>
>> 	/* Get driver entry */
>> #if 0
>> 	rv = sd_card_driver_get_entry(minor, &e);
>> 	CHECK_RVSC( rv, "Get driver entry");
>> #else
>> 	e = &sd_card_driver_table[0];
>> #endif
>>
>> 	/* Start */
>> 	sc = sd_card_start(e);   <---this failed with #if 0 code!
>>
>> I made the same change in sd_card_driver_read(), not sure if it is called.
>>
>> Looking at the HEAD version of spi-sd-card.c, I see it has been changed 
>> so that there would only be a single "major" instance generated per bus 
>> device (in my case one SPI device).  Also functions 
>> sd_card_driver_write/read() are removed from HEAD. However, the 
>> "write_entry" function is now rtems_blkdev_generic_write (not defined in 
>> 4.9.1). Hopefully the correct function will be called when msdosfmt code 
>> calls rtems_blkdev_generic_write().
>>

I am wrong. The "generic" blk read/write *are* in 4.9.x.

> 
> Maybe these threads will help explain what has changed:
> 
>   http://www.rtems.com/ml/rtems-users/2008/october/msg00120.html
>   http://www.rtems.com/ml/rtems-users/2008/november/msg00050.html

Yes, I remember seeing this now and being totally snowed.

> 
> Given what you say I suspect the CVS version will format the card.
> 
> 
> Regards
> Chris

Yes, I think Robert S. Grimes was seeing his write to "absolute" sector 
not work for the same reason. So if these "generic" functions are used 
they are buffered by the cache during format, I think. Is that OK? Seems 
like fmt should be done on an unmounted device and do immediate sector 
writes? But if it's OK, can the fixes to spi-sd-card.c from 1.7 to 1.8 
be merged in to 1.6.2.1? Lots of changes in the diff. Otherwise, 
msdosfmt of SD/MMC is broken on the 4.9 branch. Or my kluge is the fix?
-gene