[PATCH] RE: Some memory (DDR2 ECC Dual Rank) just doesn't work! Can anyone pointme to how to debug this hang?

[PATCH] RE: Some memory (DDR2 ECC Dual Rank) just doesn't work! Can anyone pointme to how to debug this hang?

[Fillod Stephane]

Vince Asbridge wrote:
> We have an 8548 design, which implements a DDR2 on a SODIMM=20
> We have an issue with dual rank memory (specific part number Viking =
VR5DR287218EBSS1), which is a 1G ECC Registered SODIMM part, with two =
ranks.
> Our platform wires CS0 and CS1 to the SODIMM slot.=20
> At uBoot, all is well.=A0 Memory is discovered as ECC 533, 1G DDR2 =
64Bit 4 beat bursts, and mtest can read and write all 1G of the SODIMM.
[...]
> Other DDR2s (identical except for vendor and # of ranks), work =
perfectly!=20
> Anyone got a clue what I could look at to try to figure this out?=20
> We've tried enable / disable ECC at uboot=20
> We've tried enable / disable Interleaving at uboot=20
> uboot always works (and can read/write entire DDR), Linux always hangs =
on boot!=20

U-Boot is too gentle when testing SDRAM. Make sure the caches are =
enabled
under U-Boot, and put on heavy stress with DMA, pipelined prefetch's, =
etc.
This is what your CPU is enduring under Linux.=20

Your question is definitely a question for the U-Boot mailing list.
BTW, what is the version of U-Boot in use? U-Boot is still missing
the following patch:

MPC85xx BA bits not set for 3-bit bank address DIMM of CS1

The current implementation set the number of bank address bits
(BA) in the processor for CS0 but not for CS1.=20

Signed-off-by: Stephane Fillod <stephane.fillod@thomson.net>

--- u-boot/cpu/mpc85xx/spd_sdram.c
+++ u-boot/cpu/mpc85xx/spd_sdram.c
@@ -365,6 +365,7 @@
                ddr->cs1_config =3D ( 1<<31
                                    | (odt_rd_cfg << 20)
                                    | (odt_wr_cfg << 16)
+                                   | (ba_bits << 14)
                                    | (spd.nrow_addr - 12) << 8
                                    | (spd.ncol_addr - 8) );
                debug("DDR: cs1_bnds   =3D 0x%08x\n", ddr->cs1_bnds);



Otherwise, recompile with -DDEBUG and CFG_CMD_SDRAM, grab the Viking =
datasheet=20
and a scope, and a full cup of coffee/tea much needed during =
cross-checking :-)

Cheers
--=20
Stephane

RE: [PATCH] RE: Some memory (DDR2 ECC Dual Rank) just doesn't work! Can anyone pointme to how to debug this hang?

[Vince Asbridge]

Stephane,

Thanks so much for your prompt reply.

We will pursue your suggestions, and let the forum know what we find.  =
We're
at 1.3.0 uboot version.

Vince

> -----Original Message-----
> From: Fillod Stephane [mailto:stephane.fillod@thomson.net]=20
> Sent: Thursday, August 14, 2008 8:06 AM
> To: Vince Asbridge; linuxppc-embedded
> Cc: u-boot@lists.denx.de
> Subject: [PATCH] RE: Some memory (DDR2 ECC Dual Rank) just=20
> doesn't work! Can anyone pointme to how to debug this hang?
>=20
> Vince Asbridge wrote:
> > We have an 8548 design, which implements a DDR2 on a SODIMM=20
> We have an=20
> > issue with dual rank memory (specific part number Viking=20
> VR5DR287218EBSS1), which is a 1G ECC Registered SODIMM part,=20
> with two ranks.
> > Our platform wires CS0 and CS1 to the SODIMM slot.=20
> > At uBoot, all is well.=A0 Memory is discovered as ECC 533, 1G=20
> DDR2 64Bit 4 beat bursts, and mtest can read and write all 1G=20
> of the SODIMM.
> [...]
> > Other DDR2s (identical except for vendor and # of ranks),=20
> work perfectly!=20
> > Anyone got a clue what I could look at to try to figure this out?=20
> > We've tried enable / disable ECC at uboot We've tried=20
> enable / disable=20
> > Interleaving at uboot uboot always works (and can read/write entire=20
> > DDR), Linux always hangs on boot!
>=20
> U-Boot is too gentle when testing SDRAM. Make sure the caches=20
> are enabled under U-Boot, and put on heavy stress with DMA,=20
> pipelined prefetch's, etc.
> This is what your CPU is enduring under Linux.=20
>=20
> Your question is definitely a question for the U-Boot mailing list.
> BTW, what is the version of U-Boot in use? U-Boot is still=20
> missing the following patch:
>=20
> MPC85xx BA bits not set for 3-bit bank address DIMM of CS1
>=20
> The current implementation set the number of bank address bits
> (BA) in the processor for CS0 but not for CS1.=20
>=20
> Signed-off-by: Stephane Fillod <stephane.fillod@thomson.net>
>=20
> --- u-boot/cpu/mpc85xx/spd_sdram.c
> +++ u-boot/cpu/mpc85xx/spd_sdram.c
> @@ -365,6 +365,7 @@
>                 ddr->cs1_config =3D ( 1<<31
>                                     | (odt_rd_cfg << 20)
>                                     | (odt_wr_cfg << 16)
> +                                   | (ba_bits << 14)
>                                     | (spd.nrow_addr - 12) << 8
>                                     | (spd.ncol_addr - 8) );
>                 debug("DDR: cs1_bnds   =3D 0x%08x\n", ddr->cs1_bnds);
>=20
>=20
>=20
> Otherwise, recompile with -DDEBUG and CFG_CMD_SDRAM, grab the=20
> Viking datasheet and a scope, and a full cup of coffee/tea=20
> much needed during cross-checking :-)
>=20
> Cheers
> --
> Stephane
>=20
>=20
>=20

Re: [PATCH] RE: Some memory (DDR2 ECC Dual Rank) just doesn't work! Can anyone pointme to how to debug this hang?

[Jon Loeliger]

Vince Asbridge wrote:
> Stephane,
> 
> Thanks so much for your prompt reply.
> 
> We will pursue your suggestions, and let the forum know what we find.  We're
> at 1.3.0 uboot version.
> 
> Vince
> 
>> -----Original Message-----
>> From: Fillod Stephane [mailto:stephane.fillod@thomson.net] 
>> Sent: Thursday, August 14, 2008 8:06 AM
>> To: Vince Asbridge; linuxppc-embedded
>> Cc: u-boot@lists.denx.de
>> Subject: [PATCH] RE: Some memory (DDR2 ECC Dual Rank) just 
>> doesn't work! Can anyone pointme to how to debug this hang?
>>
>> Vince Asbridge wrote:
>>> We have an 8548 design, which implements a DDR2 on a SODIMM 
>> We have an 
>>> issue with dual rank memory (specific part number Viking 
>> VR5DR287218EBSS1), which is a 1G ECC Registered SODIMM part, 
>> with two ranks.
>>> Our platform wires CS0 and CS1 to the SODIMM slot. 
>>> At uBoot, all is well.  Memory is discovered as ECC 533, 1G 
>> DDR2 64Bit 4 beat bursts, and mtest can read and write all 1G 
>> of the SODIMM.
>> [...]
>>> Other DDR2s (identical except for vendor and # of ranks), 
>> work perfectly! 
>>> Anyone got a clue what I could look at to try to figure this out? 
>>> We've tried enable / disable ECC at uboot We've tried 
>> enable / disable 
>>> Interleaving at uboot uboot always works (and can read/write entire 
>>> DDR), Linux always hangs on boot!
>> U-Boot is too gentle when testing SDRAM. Make sure the caches 
>> are enabled under U-Boot, and put on heavy stress with DMA, 
>> pipelined prefetch's, etc.
>> This is what your CPU is enduring under Linux. 
>>
>> Your question is definitely a question for the U-Boot mailing list.
>> BTW, what is the version of U-Boot in use? U-Boot is still 
>> missing the following patch:
>>
>> MPC85xx BA bits not set for 3-bit bank address DIMM of CS1
>>
>> The current implementation set the number of bank address bits
>> (BA) in the processor for CS0 but not for CS1. 
>>
>> Signed-off-by: Stephane Fillod <stephane.fillod@thomson.net>
>>
>> --- u-boot/cpu/mpc85xx/spd_sdram.c
>> +++ u-boot/cpu/mpc85xx/spd_sdram.c
>> @@ -365,6 +365,7 @@
>>                 ddr->cs1_config = ( 1<<31
>>                                     | (odt_rd_cfg << 20)
>>                                     | (odt_wr_cfg << 16)
>> +                                   | (ba_bits << 14)
>>                                     | (spd.nrow_addr - 12) << 8
>>                                     | (spd.ncol_addr - 8) );
>>                 debug("DDR: cs1_bnds   = 0x%08x\n", ddr->cs1_bnds);
>>
>>
>>
>> Otherwise, recompile with -DDEBUG and CFG_CMD_SDRAM, grab the 
>> Viking datasheet and a scope, and a full cup of coffee/tea 
>> much needed during cross-checking :-)
>>


That bug fix, along with many, many others, as well as some
new support for multiple controllers and such are all present
in the DDR re-write patch set that Kumar just posted.  You may
want to try that code too.  It will be replacing the entire
85xx/86xx and eventually the 83xx line of memory controller
initialization.  It also contains some support for a pretty
useful interactive DDR configuration setup mechanism too.

jdl

Re: [PATCH] RE: Some memory (DDR2 ECC Dual Rank) just doesn't work! Can anyone pointme to how to debug this hang?

[Wolfgang Denk]

Dear Fillod,

In message <0B45E93C5FF65740AEAE690BF3848B7AD38359@rennsmail04.eu.thmulti.com> you wrote:
> 
> U-Boot is too gentle when testing SDRAM. Make sure the caches are enabled
> under U-Boot, and put on heavy stress with DMA, pipelined prefetch's, etc.
> This is what your CPU is enduring under Linux. =

Jon Loeliger thinks this will be fixed by Kumar's DDR patches that are
about to be checked in. Please test is this is correct, and report
back if it doesn't.

Thanks.

Best regards,

Wolfgang Denk

-- 
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