On 05/29/2014 01:44 PM, Steve Rae wrote: > > > 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
Yes. > Then the usage would become: > mmc->block_dev.specified_hw_part = 1; /* specify Boot1 partition */ The only code that would need to assign that field is disk/part.c:get_dev() or something called from it. that is the function that's responsible for looking up or creating the block_dev_desc_t "handle" for a user-specified storage device, so it's exactly the place for this kind of object "constructor" code to execute. > mmc->block_dev.block_read(0, 0, 1, buf); /* read first block (from > Boot1 partition) */ Yes. > 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... Oh, but it is:-) _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
