From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Frysinger Date: Mon, 21 Jan 2008 08:01:48 -0500 Subject: [U-Boot-Users] "stacked" memory mapped flash assisted with GPIOs In-Reply-To: <20080121130006.1fc7b5ce@dhcp-252-066.norway.atmel.com> References: <200801200556.11352.vapier@gentoo.org> <20080121130006.1fc7b5ce@dhcp-252-066.norway.atmel.com> Message-ID: <200801210801.49358.vapier@gentoo.org> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de On Monday 21 January 2008, Haavard Skinnemoen wrote: > Mike Frysinger 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 -------------- next part -------------- A non-text attachment was scrubbed... Name: not available Type: application/pgp-signature Size: 827 bytes Desc: This is a digitally signed message part. Url : http://lists.denx.de/pipermail/u-boot/attachments/20080121/9230661a/attachment.pgp