On 11/11/2013 10:49 AM, Scott Wood wrote: > On Fri, 2013-11-08 at 20:25 -0600, sun york-R58495 wrote: >> On Nov 8, 2013, at 4:48 PM, Scott Wood wrote: >> >>> On Wed, 2013-10-30 at 19:07 -0700, York Sun wrote: >>>> >>>> + CONFIG_SYS_FSL_DDR >>>> + Freescale DDR driver in use. This type of DDR controller is >>>> + found in mpc83xx, mpc85xx, mpc86xx as well as some ARM core >>>> + SoCs. >>>> + >>>> + CONFIG_SYS_FSL_DDR_ADDR >>>> + Freescale DDR memory-mapped register base. >>>> + >>>> + CONFIG_SYS_FSL_DDR_EMU >>>> + Specify emulator support for DDR. Some DDR features such as >>>> + deskew training are not available. >>>> + >>>> + CONFIG_SYS_FSL_DDR_PPC_GEN1 >>>> + Freescale DDR1 controller. >>>> + >>>> + CONFIG_SYS_FSL_DDR_PPC_GEN2 >>>> + Freescale DDR2 controller. >>>> + >>>> + CONFIG_SYS_FSL_DDR_PPC_GEN3 >>>> + Freescale DDR3 controller. >>> >>> Why is there "PPC" in the name if this is to be common for PPC and ARM? >>> The description is more generic than the config symbol... >> >> This patch moves the DDR driver out of powerpc. I should deal with the >> common part for ARM and PPC later. Good point. >> >>> >>>> + CONFIG_FSL_DDR1 >>>> + User config to use DDR1. It can be enabled for SoCs with >>>> + Freescale DDR1 or DDR2 controllers. >>>> + >>>> + CONFIG_FSL_DDR2 >>>> + User config to use DDR2. It can be eanbeld for SoCs with >>>> + Freescale DDR2 or DDR3 controllers. >>>> + >>>> + CONFIG_FSL_DDR3 >>>> + User config to use DDR3. It can be enabled for SoCs with >>>> + Freescale DDR3 controllers. >>> >>> How is this user config, rather than a description of the type of DDR >>> that is present? >> >> The DDR controller may support more than one type of memory. DDR2 >> controllers support both DDR1 and DDR2, and some DDR3 controllers >> support both DDR2 and DDR3. It's user's option to choose which type of >> DDR devices to use. The driver needs to deal with them differently. You >> may argue the driver should detect them and choose the algorithm >> differently. But that will increase the code size considerably. It >> makes less sense to do so because once the board is designed, it is >> either this or that. > > My point is that the type of DDR that is present is hardware > description, just as much as the type of DDR controller. "User config" > means things users can choose purely in software, without a > corresponding hardware change. >
This is a board-level configuration, not SoC level. Should we use CONFIG_SYS_ as well? If so, we need to come up with a new name, such as CONFIG_SYS_FSL_DDR_MEM_GEN3. York _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
