[U-Boot] [Patch v3 1/2] powerpc/mpc8xxx: Fix DDR3 timing_cfg_1 and sdram_mode registers

York Sun yorksun at freescale.com
Wed Mar 2 22:26:33 CET 2011


The write recovery time of both registers should match. Since mode register
doesn't support cycles of 9,11,13,15, we should use next higher number for
both registers.

Signed-off-by: York Sun <yorksun at freescale.com>
---
 arch/powerpc/cpu/mpc8xxx/ddr/ctrl_regs.c |   20 ++++++++++++++------
 1 files changed, 14 insertions(+), 6 deletions(-)

diff --git a/arch/powerpc/cpu/mpc8xxx/ddr/ctrl_regs.c b/arch/powerpc/cpu/mpc8xxx/ddr/ctrl_regs.c
index 41bad35..06064a5 100644
--- a/arch/powerpc/cpu/mpc8xxx/ddr/ctrl_regs.c
+++ b/arch/powerpc/cpu/mpc8xxx/ddr/ctrl_regs.c
@@ -333,6 +333,9 @@ static void set_timing_cfg_1(fsl_ddr_cfg_regs_t *ddr,
 	unsigned char acttoact_mclk;
 	/* Last write data pair to read command issue interval (tWTR) */
 	unsigned char wrtord_mclk;
+	/* DDR_SDRAM_MODE doesn't support 9,11,13,15 */
+	const u8 wrrec_table[] = {
+		1, 2, 3, 4, 5, 6, 7, 8, 10, 10, 12, 12, 14, 14, 0, 0};
 
 	pretoact_mclk = picos_to_mclk(common_dimm->tRP_ps);
 	acttopre_mclk = picos_to_mclk(common_dimm->tRAS_ps);
@@ -371,6 +374,8 @@ static void set_timing_cfg_1(fsl_ddr_cfg_regs_t *ddr,
 
 	refrec_ctrl = picos_to_mclk(common_dimm->tRFC_ps) - 8;
 	wrrec_mclk = picos_to_mclk(common_dimm->tWR_ps);
+
+	wrrec_mclk = wrrec_table[wrrec_mclk - 1];
 	if (popts->OTF_burst_chop_en)
 		wrrec_mclk += 2;
 
@@ -810,6 +815,12 @@ static void set_ddr_sdram_mode(fsl_ddr_cfg_regs_t *ddr,
 	unsigned int bl;	/* BL: Burst Length */
 
 	unsigned int wr_mclk;
+	/*
+	 * DDR_SDRAM_MODE doesn't support 9,11,13,15
+	 * Please refer JEDEC Standard No. 79-3E for Mode Register MR0
+	 * for this table
+	 */
+	const u8 wr_table[] = {1, 2, 3, 4, 5, 5, 6, 6, 7, 7, 0, 0};
 
 	const unsigned int mclk_ps = get_memory_clk_period_ps();
 	int i;
@@ -853,13 +864,10 @@ static void set_ddr_sdram_mode(fsl_ddr_cfg_regs_t *ddr,
 	 * 1=fast exit DLL on (tXP)
 	 */
 	dll_on = 1;
+
 	wr_mclk = (common_dimm->tWR_ps + mclk_ps - 1) / mclk_ps;
-	if (wr_mclk >= 12)
-		wr = 6;
-	else if (wr_mclk >= 9)
-		wr = 5;
-	else
-		wr = wr_mclk - 4;
+	wr = wr_table[wr_mclk - 5];
+
 	dll_rst = 0;	/* dll no reset */
 	mode = 0;	/* normal mode */
 
-- 
1.7.0.4




More information about the U-Boot mailing list