Re: how do i add the defn for the beagle xM to barebox?

["Eric Bénard" <eric@eukrea.com>]

Le Sun, 5 Feb 2012 10:37:59 -0500 (EST),
"Robert P. J. Day" <rpjday@crashcourse.ca> a écrit :

> On Sun, 5 Feb 2012, Eric Bénard wrote:
> 
> > Hi Robert,
> >
> > Le Sun, 5 Feb 2012 06:52:28 -0500 (EST),
> > "Robert P. J. Day" <rpjday@crashcourse.ca> a écrit :
> > >   thoughts?  i'd actually like to make the tweaks one at a time so
> > > that the git log shows clearly how the two boards differ one feature
> > > at a time.
> >
> > By sensing a few GPIO, you can easily check which board you are running
> > barebox on and thus have ony binary which supports all beagleboards
> > (as already done in u-boot).
> >
> > Check around line 108 in u-boot's beagle support for the details :
> > http://git.denx.de/?p=u-boot.git;a=blob;f=board/ti/beagle/beagle.c;h=5c04b34e1ab0140aca93e7752c8672ce7aebc0b9;hb=HEAD
> >
> > So in the end you can register the nand support only if you run on a
> > board which has a NAND flash and have one defconfig for all
> > beagleboards (some tweaks in the clock settings may be nedded -
> > especially for USB IIRC - as beagle XM is built around a DM3730 which
> > can run at 1GHz when older beagles had older OMAP3530 limited to
> > 720MHz).
> 
>   hmmmm ... i see one possible problem that maybe means i just haven't
> read far enough.  in u-boot, in that beagle.c file, here's a chunk of
> code that identifies the NAND chip, of which there is none on the xM:
> 
> /*
>          * We need to identify what PoP memory is on the board so that
>          * we know what timings to use.  If we can't identify it then
>          * we know it's an xM.  To map the ID values please see nand_ids.c
>          */
>         identify_nand_chip(&pop_mfr, &pop_id);
> 
>         *mr = MICRON_V_MR_165;
>         switch (get_board_revision()) {
>         case REVISION_C4:
>                 if (pop_mfr == NAND_MFR_STMICRO && pop_id == 0xba) {
>                         /* 512MB DDR */
>                         *mcfg = NUMONYX_V_MCFG_165(512 << 20);
>                         *ctrla = NUMONYX_V_ACTIMA_165;
>                         *ctrlb = NUMONYX_V_ACTIMB_165;
>                         *rfr_ctrl = SDP_3430_SDRC_RFR_CTRL_165MHz;
>                         break;
>                 } else if (pop_mfr == NAND_MFR_MICRON && pop_id == 0xbc) {
>                         /* Beagleboard Rev C5, 256MB DDR */
>                         *mcfg = MICRON_V_MCFG_200(256 << 20);
>                         *ctrla = MICRON_V_ACTIMA_200;
>                         *ctrlb = MICRON_V_ACTIMB_200;
>                         *rfr_ctrl = SDP_3430_SDRC_RFR_CTRL_200MHz;
>                         break;
>                 }
>         case REVISION_XM_A:
>         case REVISION_XM_B:
>         case REVISION_XM_C:
>                 if (pop_mfr == 0) {
>                         /* 256MB DDR */
>                         *mcfg = MICRON_V_MCFG_200(256 << 20);
>                         *ctrla = MICRON_V_ACTIMA_200;
>                         *ctrlb = MICRON_V_ACTIMB_200;
>                         *rfr_ctrl = SDP_3430_SDRC_RFR_CTRL_200MHz;
>                 } else {
>                         /* 512MB DDR */
>                         *mcfg = NUMONYX_V_MCFG_165(512 << 20);
>                         *ctrla = NUMONYX_V_ACTIMA_165;
>                         *ctrlb = NUMONYX_V_ACTIMB_165;
>                         *rfr_ctrl = SDP_3430_SDRC_RFR_CTRL_165MHz;
>                 }
>                 break;
> 		... snip ...
> 
>   ok, i can see how that works, but if you need to test this way, it
> means that you'll constantly be overriding the CONFIG settings in the
> beagle defconfig file.
> 
>   if i read you correctly, then one should be able to use the same
> defconfig file for both a regular beagle and an xM.  but the current
> barebox beagle xload defconfig file contains stuff like:
> 
> CONFIG_MTD=y
> # CONFIG_MTD_WRITE is not set
> # CONFIG_MTD_OOB_DEVICE is not set
> CONFIG_NAND=y
> # CONFIG_NAND_ECC_SOFT is not set
> # CONFIG_NAND_ECC_HW_SYNDROME is not set
> # CONFIG_NAND_ECC_HW_NONE is not set
> # CONFIG_NAND_INFO is not set
> # CONFIG_NAND_BBT is not set
> CONFIG_NAND_OMAP_GPMC=y
> 
> which is fine for a regular beagle but totally wrong for an xM.  does
> this mean that, with an xM, i'd include the same (incorrect) defconfig
> file, and have to be constantly overriding some of those settings?
> 
>   i can see how getting the board revision lets you test how to do
> things differently across a related set of boards.  but the difference
> between a regular beagle and an xM is *sizable* when you're talking
> about NAND versus no NAND.  ideally, i'd like to have that board
> revision test available in the defconfig file itself. :-)
> 
This is the case where u-boot is built with SPL thus reoplacing
x-load : they always read NAND ID as some XM boards were mounted with
Numonyx POP which includes NAND and 166MHz RAM when mot XM boards have
a POP with only 200MHz DDR (and in that case manufacturer ID is 0). So
even on a XM you need to check the NAND ID to set the right RAM
settings.

Eric
-- 
http://eukrea.com/en/news/104-2012

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