On 07/10/2012 07:58 AM, Albert ARIBAUD wrote:
Hi Andreas,
On Fri, 06 Jul 2012 12:25:00 +0200, "Andreas Bießmann" andreas.devel@googlemail.com wrote:
Dear Yann Vernier,
On 06.07.2012 11:14, Yann Vernier wrote:
On Friday 06 July 2012 10:43:40 you wrote:
> =((CONFIG_SYS_SDRAM_BASE+CONFIG_SYS_SDRAM_SIZE-0x10000)<<(22-16) | \ + > (CONFIG_SYS_SDRAM_BASE>>(16-12) | 0x00e))
ugh ... magic. Will it work for every possible setting? How about one setting CONFIG_SYS_SDRAM_BASE != 0x0? I the base address related to register content in any way?
It's not a guarded secret, although it is far from obvious where to find it. One way is micrel.com - Products - Ethernet ICs / ARM based SOC's - HW Design Kit. Within that zip file, KS8695X_EVAL_HW_RV4.0_DP/RegDescription/KS8695X Register Description v1.1.pdf
With this information I understand your equation. I think you should not do it that way. You may solve the current state (all devices have 8 column, 4 bank and 32 bit). But one adding (well, if that will ever come ;) another board with different setting will get in trouble here and need to find another solution. Maybe more sophisticated by doing another equation.
I think a straight forward solution here would be to add another special define in the board config, write the magic number down there and maybe describe what the number stands for. You can then just use the previously defined value in start.S. You may have a look for at91 lowlevel_init, there it is done that way.
I shall. In fact, I may already have this problem as I need to verify the timing on the flash memory (I have the demo board, not a cm4xxx), and the reason I work on this is that we may design another board soon.
I'm a little hesitant about how to fit these changes together, though; for now I have three barely separated patches, but overhauling all those magic numbers changes them all yet again. These three patches are all necessary to make my u-boot work in the first place, while fixing the magic values is a code cleanup change - probably editing arch/arm/include/asm/arch-ks8695/platform.h which currently contains a few meaningless constants like KS8695_SDRAM_START and a consistent misspelling of definitions.
Could I save the value decoding and corresponding configuration changes for a fourth patch?
I'm fine with this suggestion. So the next question is who would pull it in mainline? Since this is arm related I guess Albert is the one in question.
Ah, board-related patches. :)
I think these three patches are all fixes to get a board already in mainline working.
Fixes or improvements?
So I think we should try to get these in -rc1.
Albert, can you please comment?
If the cm4008/cm41xx board maintainer (as per MAINTAINERS, this is Greg Ungerer, Cc:) green-lights it, then I'm ok for pulling it in.
I have no problem with them. I have only done a visual inspection of the revised patches in the mail archives, and not tested them on the real hardware.
I would suggest defining the proper meanings of the remaining bits in the SDRAM setup registers that are still magic numbers, but that can be a future change.
Acked-by: Greg Ungerer greg.ungerer@opengear.com
Regards Greg