[U-Boot] [PATCH v5 09/16] driver/ddr/fsl: Add support of overriding chip select write leveling

[Alison Wang <b18965@freescale.com>]

From: York Sun <yorksun@freescale.com>

JEDEC spec allows DRAM vendors to use prime DQ for write leveling. This
is not an issue unless some DQ pins are not connected. If a platform uses
regular DIMMs but with reduced DDR ECC pins, the prime DQ may end up on
those floating pins for the second rank. The workaround is to use a known
good chip select for this purpose.

Signed-off-by: York Sun <yorksun@freescale.com>
---
Change log:
 v5: No change.
 v4: No change.
 v3: No change.
 v2: No change.

 drivers/ddr/fsl/ctrl_regs.c   | 3 +++
 drivers/ddr/fsl/interactive.c | 2 ++
 include/fsl_ddr_sdram.h       | 2 ++
 3 files changed, 7 insertions(+)

diff --git a/drivers/ddr/fsl/ctrl_regs.c b/drivers/ddr/fsl/ctrl_regs.c
index 5e0ee77..d9cac22 100644
--- a/drivers/ddr/fsl/ctrl_regs.c
+++ b/drivers/ddr/fsl/ctrl_regs.c
@@ -2276,6 +2276,9 @@ compute_fsl_memctl_config_regs(const memctl_options_t *popts,
 	if (ip_rev > 0x40400)
 		unq_mrs_en = 1;
 
+	if (ip_rev > 0x40700)
+		ddr->debug[18] = popts->cswl_override;
+
 	set_ddr_sdram_cfg_2(ddr, popts, unq_mrs_en);
 	set_ddr_sdram_mode(ddr, popts, common_dimm,
 				cas_latency, additive_latency, unq_mrs_en);
diff --git a/drivers/ddr/fsl/interactive.c b/drivers/ddr/fsl/interactive.c
index 7fb4187..6aa16b2 100644
--- a/drivers/ddr/fsl/interactive.c
+++ b/drivers/ddr/fsl/interactive.c
@@ -511,6 +511,7 @@ static void fsl_ddr_options_edit(fsl_ddr_info_t *pinfo,
 		CTRL_OPTIONS(wrlvl_override),
 		CTRL_OPTIONS(wrlvl_sample),
 		CTRL_OPTIONS(wrlvl_start),
+		CTRL_OPTIONS(cswl_override),
 		CTRL_OPTIONS(rcw_override),
 		CTRL_OPTIONS(rcw_1),
 		CTRL_OPTIONS(rcw_2),
@@ -801,6 +802,7 @@ static void print_memctl_options(const memctl_options_t *popts)
 		CTRL_OPTIONS(wrlvl_override),
 		CTRL_OPTIONS(wrlvl_sample),
 		CTRL_OPTIONS(wrlvl_start),
+		CTRL_OPTIONS_HEX(cswl_override),
 		CTRL_OPTIONS(rcw_override),
 		CTRL_OPTIONS(rcw_1),
 		CTRL_OPTIONS(rcw_2),
diff --git a/include/fsl_ddr_sdram.h b/include/fsl_ddr_sdram.h
index e8a2db9..987119b 100644
--- a/include/fsl_ddr_sdram.h
+++ b/include/fsl_ddr_sdram.h
@@ -281,6 +281,7 @@ typedef struct memctl_options_partial_s {
 #define DDR_DATA_BUS_WIDTH_64 0
 #define DDR_DATA_BUS_WIDTH_32 1
 #define DDR_DATA_BUS_WIDTH_16 2
+#define DDR_CSWL_CS0	0x04000001
 /*
  * Generalized parameters for memory controller configuration,
  * might be a little specific to the FSL memory controller
@@ -340,6 +341,7 @@ typedef struct memctl_options_s {
 	unsigned int cpo_override;
 	unsigned int write_data_delay;		/* DQS adjust */
 
+	unsigned int cswl_override;
 	unsigned int wrlvl_override;
 	unsigned int wrlvl_sample;		/* Write leveling */
 	unsigned int wrlvl_start;
-- 
1.8.0