fsl-ddr: add override for the Rtt_Wr

Different boards may require different settings of Dynamic ODT (Rtt_Wr).
We provide a means to allow the board specific code to provide its own
value of Rtt_Wr.

Signed-off-by: Dave Liu <daveliu@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>

diff --git a/cpu/mpc8xxx/ddr/ctrl_regs.c b/cpu/mpc8xxx/ddr/ctrl_regs.c
index 5e37ca6..3be7e22 100644 (file)
--- a/cpu/mpc8xxx/ddr/ctrl_regs.c
+++ b/cpu/mpc8xxx/ddr/ctrl_regs.c
@@ -576,18 +576,22 @@ static void set_ddr_sdram_cfg_2(fsl_ddr_cfg_regs_t *ddr,
 }
 
 /* DDR SDRAM Mode configuration 2 (DDR_SDRAM_MODE_2) */
-static void set_ddr_sdram_mode_2(fsl_ddr_cfg_regs_t *ddr)
+static void set_ddr_sdram_mode_2(fsl_ddr_cfg_regs_t *ddr,
+                               const memctl_options_t *popts)
 {
        unsigned short esdmode2 = 0;    /* Extended SDRAM mode 2 */
        unsigned short esdmode3 = 0;    /* Extended SDRAM mode 3 */
 
 #if defined(CONFIG_FSL_DDR3)
-       unsigned int rtt_wr = 2;        /* 120 ohm Rtt_WR */
+       unsigned int rtt_wr = 0;        /* Rtt_WR - dynamic ODT off */
        unsigned int srt = 0;   /* self-refresh temerature, normal range */
        unsigned int asr = 0;   /* auto self-refresh disable */
        unsigned int cwl = compute_cas_write_latency() - 5;
        unsigned int pasr = 0;  /* partial array self refresh disable */
 
+       if (popts->rtt_override)
+               rtt_wr = popts->rtt_wr_override_value;
+
        esdmode2 = (0
                | ((rtt_wr & 0x3) << 9)
                | ((srt & 0x1) << 7)
@@ -1330,7 +1334,7 @@ compute_fsl_memctl_config_regs(const memctl_options_t *popts,
        set_ddr_sdram_cfg_2(ddr, popts);
        set_ddr_sdram_mode(ddr, popts, common_dimm,
                                cas_latency, additive_latency);
-       set_ddr_sdram_mode_2(ddr);
+       set_ddr_sdram_mode_2(ddr, popts);
        set_ddr_sdram_interval(ddr, popts, common_dimm);
        set_ddr_data_init(ddr);
        set_ddr_sdram_clk_cntl(ddr, popts);

diff --git a/include/asm-ppc/fsl_ddr_sdram.h b/include/asm-ppc/fsl_ddr_sdram.h
index 15ab675..3216a50 100644 (file)
--- a/include/asm-ppc/fsl_ddr_sdram.h
+++ b/include/asm-ppc/fsl_ddr_sdram.h
@@ -192,6 +192,7 @@ typedef struct memctl_options_s {
        /* Rtt impedance */
        unsigned int rtt_override;              /* rtt_override enable */
        unsigned int rtt_override_value;        /* that is Rtt_Nom for DDR3 */
+       unsigned int rtt_wr_override_value;     /* this is Rtt_WR for DDR3 */
 
        /* Automatic self refresh */
        unsigned int auto_self_refresh_en;