On 14-05-29 11:51 AM, Stephen Warren wrote:
On 05/29/2014 11:58 AM, Steve Rae wrote:
Hi, Stephen
On 14-05-29 09:25 AM, Stephen Warren wrote:
On 05/28/2014 04:15 PM, Steve Rae wrote:
Each wrapper function:
- switches to the specified physical partition, then
- performs the original function, and then
- switches back to the original physical partition
where the physical partition (aka HW partition) is
0=User, 1=Boot1, 2=Boot2, etc.
This feels wrong; why wouldn't mmc_get_dev() return a block_dev_desc_t
containing block_read/block_write functions that do the HW partition
switching. That way, this is all completely hidden, and all client code
only knows about block devices, rather than having to know about
MMC-specific mmc_block_read/write/erase_hwpart() functions.
This goes back to the initial discussion on this mailing list (which was
never resolved):
http://lists.denx.de/pipermail/u-boot/2014-April/178171.html
This issue is that the three callback functions defined in
'block_desc_t' do not accept the "partition number" as an argument.
It was suggested that we could overwrite those functions; but the
"partition number" still needs to be passed in by:
(1) overloading the "int dev_num" argument, or
(2) adding another argument to the callback functions
I assumed that neither of these was acceptable, so I have proposed these
wrappers...
Can't the data simply be stored in the block_desc_t itself?
If I understand this suggestion, are you proposing:
- add an "unsigned int specified_hw_part" to the block_desc_t
Then the usage would become:
mmc->block_dev.specified_hw_part = 1; /* specify Boot1 partition */
mmc->block_dev.block_read(0, 0, 1, buf); /* read first block (from
Boot1 partition) */
mmc->block_dev.specified_hw_part = 0; /* specify User partition */
mmc->block_dev.block_read(0, 0, 1, buf); /* read first block (from User
partition) */
I don't think this is a good idea...
Please clarify!
Thanks, Steve
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