From 58edbc9caaef4efbf12de8a451d70c2ad86934bf Mon Sep 17 00:00:00 2001 From: York Sun Date: Mon, 18 Oct 2010 13:46:50 -0700 Subject: [PATCH] Disable unused chip-select for DDR controller interleaving When DDR controller interleaving is eabled and less than all bank (chip-select) interleaving is seletected, the unused chip-select should be disabled. Signed-off-by: York Sun Signed-off-by: Kumar Gala --- arch/powerpc/cpu/mpc8xxx/ddr/ctrl_regs.c | 17 ++++++++++++++--- 1 file changed, 14 insertions(+), 3 deletions(-) diff --git a/arch/powerpc/cpu/mpc8xxx/ddr/ctrl_regs.c b/arch/powerpc/cpu/mpc8xxx/ddr/ctrl_regs.c index e82082e..3fec100 100644 --- a/arch/powerpc/cpu/mpc8xxx/ddr/ctrl_regs.c +++ b/arch/powerpc/cpu/mpc8xxx/ddr/ctrl_regs.c @@ -1184,6 +1184,7 @@ compute_fsl_memctl_config_regs(const memctl_options_t *popts, unsigned int sr_it; unsigned int zq_en; unsigned int wrlvl_en; + int cs_en = 1; memset(ddr, 0, sizeof(fsl_ddr_cfg_regs_t)); @@ -1250,16 +1251,23 @@ compute_fsl_memctl_config_regs(const memctl_options_t *popts, * and each controller uses rank interleaving within * itself. Therefore the starting and ending address * on each controller is twice the amount present on - * each controller. + * each controller. If any CS is not included in the + * interleaving, the memory on that CS is not accssible + * and the total memory size is reduced. The CS is also + * disabled. */ unsigned long long ctlr_density = 0; switch (popts->ba_intlv_ctl & FSL_DDR_CS0_CS1_CS2_CS3) { case FSL_DDR_CS0_CS1: case FSL_DDR_CS0_CS1_AND_CS2_CS3: ctlr_density = dimm_params[0].rank_density * 2; + if (i > 1) + cs_en = 0; break; case FSL_DDR_CS2_CS3: ctlr_density = dimm_params[0].rank_density; + if (i > 0) + cs_en = 0; break; case FSL_DDR_CS0_CS1_CS2_CS3: /* @@ -1379,8 +1387,11 @@ compute_fsl_memctl_config_regs(const memctl_options_t *popts, ); debug("FSLDDR: cs[%d]_bnds = 0x%08x\n", i, ddr->cs[i].bnds); - set_csn_config(dimm_number, i, ddr, popts, dimm_params); - set_csn_config_2(i, ddr); + if (cs_en) { + set_csn_config(dimm_number, i, ddr, popts, dimm_params); + set_csn_config_2(i, ddr); + } else + printf("CS%d is disabled.\n", i); } set_ddr_eor(ddr, popts); -- 2.7.4