On Monday 21 January 2008, Haavard Skinnemoen wrote:
Mike Frysinger vapier@gentoo.org wrote:
- have memory display / flash write commands toggle the GPIO lines
- pros: user interface is transparent and not confusing by making it
seem like 1 flash exists (think software raid 0). able to use 1 write command and the lower layers will automatically split it across multiple flashes. should work with multiple types of flashes.
- cons: requires modification to cmd_mem.c and cfi_flash.c.
Wouldn't it be enough to just modify the blackfin-specific implementation of map_physmem() and unmap_physmem()? Just use some of the physical address bits to toggle the necessary GPIO lines and return a suitable pointer into the 4MB memory window.
i'm working with u-boot-1.1.6 at the moment (will probably be syncing to mainline in the next month or two) so i didnt see these hooks added to the cfi_flash.c driver.
that would allow board porters to select an arbitrary address and say "if you wish to erase/write the flash in a contiguous manner, you need to use the base address 0x........ rather than the real base address 0x........". however, from what i can see, this would only account for erase/writes. reads are done directly by u-boot using physical addresses, so those have no provision for catching accesses. -mike