[U-Boot] [PATCH] fsl-ddr: Fix some bugs in the ddr infrastructure

[Dave Liu]

1. wr_lat
   UM said the total write latency for DDR2 is equal to
   WR_LAT + ADD_LAT, the write latency is CL + ADD_LAT - 1.
   so, the WR_LAT = CL - 1;
2. rd_to_pre
   we missed to add the ADD_LAT for DDR2 case and check
   the min tRTP.
3. wr_to_rd
   add the check the min requirement for tWTR.

Reported-by: Joakim Tjernlund <Joakim.Tjernlund at transmode.se>
Signed-off-by: Dave Liu <daveliu at freescale.com>
---
 cpu/mpc8xxx/ddr/ctrl_regs.c |   11 ++++++++++-
 1 files changed, 10 insertions(+), 1 deletions(-)

diff --git a/cpu/mpc8xxx/ddr/ctrl_regs.c b/cpu/mpc8xxx/ddr/ctrl_regs.c
index 292980d..5c3e383 100644
--- a/cpu/mpc8xxx/ddr/ctrl_regs.c
+++ b/cpu/mpc8xxx/ddr/ctrl_regs.c
@@ -253,6 +253,10 @@ static void set_timing_cfg_1(fsl_ddr_cfg_regs_t *ddr,
 	wrrec_mclk = picos_to_mclk(common_dimm->tWR_ps);
 	acttoact_mclk = picos_to_mclk(common_dimm->tRRD_ps);
 	wrtord_mclk = picos_to_mclk(common_dimm->tWTR_ps);
+#if defined(CONFIG_FSL_DDR2)
+	if (wrtord_mclk < 2)
+		wrtord_mclk = 2;
+#endif
 
 	ddr->timing_cfg_1 = (0
 		| ((pretoact_mclk & 0x0F) << 28)
@@ -302,12 +306,17 @@ static void set_timing_cfg_2(fsl_ddr_cfg_regs_t *ddr,
 	 */
 	wr_lat = 0;
 #elif defined(CONFIG_FSL_DDR2)
-	wr_lat = cas_latency + additive_latency - 1;
+	wr_lat = cas_latency - 1;
 #else
 #error "Fix WR_LAT for DDR3"
 #endif
 
 	rd_to_pre = picos_to_mclk(common_dimm->tRTP_ps);
+#if defined(CONFIG_FSL_DDR2)
+	if (rd_to_pre < 2)
+		rd_to_pre = 2;
+	rd_to_pre += additive_latency;
+#endif
 	wr_data_delay = popts->write_data_delay;
 	cke_pls = picos_to_mclk(popts->tCKE_clock_pulse_width_ps);
 	four_act = picos_to_mclk(popts->tFAW_window_four_activates_ps);
-- 
1.5.4