Ok, I will drop this patch and maintain it locally. Regards Priyanka
> -----Original Message----- > From: sun york-R58495 > Sent: Thursday, October 31, 2013 10:50 AM > To: Jain Priyanka-B32167 > Cc: sun york-R58495; u-boot@lists.denx.de; Aggrwal Poonam-B10812 > Subject: Re: [PATCH] powerpc/t1040qds: Add DDR Raw Timing support > > > On Oct 30, 2013, at 9:55 PM, Jain Priyanka-B32167 wrote: > > > > >> -----Original Message----- > >> From: sun york-R58495 > >> Sent: Wednesday, October 30, 2013 10:14 PM > >> To: Jain Priyanka-B32167; u-boot@lists.denx.de > >> Cc: Aggrwal Poonam-B10812 > >> Subject: Re: [PATCH] powerpc/t1040qds: Add DDR Raw Timing support > >> > >> On 10/25/2013 02:49 AM, Priyanka Jain wrote: > >>> T1040QDS-D3 has dual-rank DDR: > >>> Micron, MT18KSF51272AZ-1G6 (4GB, x72, CL=10). > >>> Add Raw Timing structure for this DDR. > >>> > >>> Typically SPD method is used for getting DDR parameter and > >>> calculating values for various DDR controller registers. > >>> > >>> But somentimes it may happen that SPD present on DDR may get > >>> accidently erased or is not working properly during initial bring-up. > >>> In that circumnstance, DDR raw timing structure can be use as > >>> fallback option for getting DDR parameters. > >>> > >>> Signed-off-by: Poonam Aggrwal <poonam.aggr...@freescale.com> > >>> Signed-off-by: Priyanka Jain <priyanka.j...@freescale.com> > >>> --- > >> > >> I don't think it is appropriate to use raw timing for this > application. > >> This board use DIMMs, not soldered DDR chips. In normal cases, this > >> piece of code is not used. It is only useful if you have a DIMM > >> without a valid SPD. You could get another DIMM. I am not saying this > >> patch is wrong, it is just useless for general public. > >> > >> York > > > > [Jain Priyanka-B32167] You are right that in case of DIMM type of > memories, raw timing may not be required. > > But there are certain scenarios in which keeping raw timing is useful > > like 1)During initial bring-up, there is a possibility that I2C bus > > may be broken, In that case boot-loader has to rely on the fallback > option of raw timing. > > 2)Also raw timings are used in emulator to test t1040. > > So, we prefer to keep raw timing as fallback option. > > It is a debug technique, not an implementation. You can use fixed > register setting as well for debugging. But it doesn't mean you have to > keep it in the final code. After you cleaning up the code, all "fixed" > code should be removed, including the raw timing parameters you are > using. Emulator target also has I2C EEPROM modeled. You should use SPD as > well. > > York _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot