[U-Boot] [Patch v2] powerpc/mpc85xx: Revise workaround for DDR-A003

[York Sun]

Existing workaround only handles one RDIMM on reference design. In case
of two RDIMMs being used, the workaround requires two separate writes to
DDR_SDRAM_MD_CNTL register.

This patch also restores two debug registers changed by the workaround.

This change has been tested on P4080 v2 platform with one and two RDIMMs
for each controller.

Signed-off-by: York Sun <yorksun at freescale.com>
Tested-by: Ben Collins <ben.c at servergy.com>
CC: James Yang <James.Yang at freescale.com>
---
Change log:
 v2: Revise commit message

 drivers/ddr/fsl/mpc85xx_ddr_gen3.c |   59 ++++++++++++++++++++++++++++++++++--
 1 file changed, 57 insertions(+), 2 deletions(-)

diff --git a/drivers/ddr/fsl/mpc85xx_ddr_gen3.c b/drivers/ddr/fsl/mpc85xx_ddr_gen3.c
index 9f04133..864976f 100644
--- a/drivers/ddr/fsl/mpc85xx_ddr_gen3.c
+++ b/drivers/ddr/fsl/mpc85xx_ddr_gen3.c
@@ -39,6 +39,9 @@ void fsl_ddr_set_memctl_regs(const fsl_ddr_cfg_regs_t *regs,
 	unsigned int csn_bnds_backup = 0, cs_sa, cs_ea, *csn_bnds_t;
 	int csn = -1;
 #endif
+#ifdef CONFIG_SYS_FSL_ERRATUM_DDR_A003
+	u32 save1, save2;
+#endif
 
 	switch (ctrl_num) {
 	case 0:
@@ -197,6 +200,8 @@ step2:
 		out_be32(&ddr->ddr_wrlvl_cntl, regs->ddr_wrlvl_cntl & 0x7fffffff);
 		out_be32(&ddr->sdram_cfg_2, regs->ddr_sdram_cfg_2 & 0xffffffeb);
 		out_be32(&ddr->mtcr, 0);
+		save1 = in_be32(&ddr->debug[12]);
+		save2 = in_be32(&ddr->debug[21]);
 		out_be32(&ddr->debug[12], 0x00000015);
 		out_be32(&ddr->debug[21], 0x24000000);
 		out_be32(&ddr->sdram_interval, regs->ddr_sdram_interval & 0xffff);
@@ -214,6 +219,16 @@ step2:
 				0x04000000		|
 				MD_CNTL_WRCW		|
 				MD_CNTL_MD_VALUE(0x02));
+#if (CONFIG_DIMM_SLOTS_PER_CTLR == 2)
+			if (!(regs->cs[2].config & SDRAM_CS_CONFIG_EN))
+				break;
+			out_be32(&ddr->sdram_md_cntl,
+				 MD_CNTL_MD_EN		|
+				 MD_CNTL_CS_SEL_CS2_CS3	|
+				 0x04000000		|
+				 MD_CNTL_WRCW		|
+				 MD_CNTL_MD_VALUE(0x02));
+#endif
 			break;
 		case 0x00100000:
 			out_be32(&ddr->sdram_md_cntl,
@@ -222,6 +237,16 @@ step2:
 				0x04000000		|
 				MD_CNTL_WRCW		|
 				MD_CNTL_MD_VALUE(0x0a));
+#if (CONFIG_DIMM_SLOTS_PER_CTLR == 2)
+			if (!(regs->cs[2].config & SDRAM_CS_CONFIG_EN))
+				break;
+			out_be32(&ddr->sdram_md_cntl,
+				 MD_CNTL_MD_EN		|
+				 MD_CNTL_CS_SEL_CS2_CS3	|
+				 0x04000000		|
+				 MD_CNTL_WRCW		|
+				 MD_CNTL_MD_VALUE(0x0a));
+#endif
 			break;
 		case 0x00200000:
 			out_be32(&ddr->sdram_md_cntl,
@@ -230,6 +255,16 @@ step2:
 				0x04000000		|
 				MD_CNTL_WRCW		|
 				MD_CNTL_MD_VALUE(0x12));
+#if (CONFIG_DIMM_SLOTS_PER_CTLR == 2)
+			if (!(regs->cs[2].config & SDRAM_CS_CONFIG_EN))
+				break;
+			out_be32(&ddr->sdram_md_cntl,
+				 MD_CNTL_MD_EN		|
+				 MD_CNTL_CS_SEL_CS2_CS3	|
+				 0x04000000		|
+				 MD_CNTL_WRCW		|
+				 MD_CNTL_MD_VALUE(0x12));
+#endif
 			break;
 		case 0x00300000:
 			out_be32(&ddr->sdram_md_cntl,
@@ -238,6 +273,16 @@ step2:
 				0x04000000		|
 				MD_CNTL_WRCW		|
 				MD_CNTL_MD_VALUE(0x1a));
+#if (CONFIG_DIMM_SLOTS_PER_CTLR == 2)
+			if (!(regs->cs[2].config & SDRAM_CS_CONFIG_EN))
+				break;
+			out_be32(&ddr->sdram_md_cntl,
+				 MD_CNTL_MD_EN		|
+				 MD_CNTL_CS_SEL_CS2_CS3	|
+				 0x04000000		|
+				 MD_CNTL_WRCW		|
+				 MD_CNTL_MD_VALUE(0x1a));
+#endif
 			break;
 		default:
 			out_be32(&ddr->sdram_md_cntl,
@@ -246,6 +291,16 @@ step2:
 				0x04000000		|
 				MD_CNTL_WRCW		|
 				MD_CNTL_MD_VALUE(0x02));
+#if (CONFIG_DIMM_SLOTS_PER_CTLR == 2)
+			if (!(regs->cs[2].config & SDRAM_CS_CONFIG_EN))
+				break;
+			out_be32(&ddr->sdram_md_cntl,
+				 MD_CNTL_MD_EN		|
+				 MD_CNTL_CS_SEL_CS2_CS3	|
+				 0x04000000		|
+				 MD_CNTL_WRCW		|
+				 MD_CNTL_MD_VALUE(0x02));
+#endif
 			printf("Unsupported RC10\n");
 			break;
 		}
@@ -259,8 +314,8 @@ step2:
 		out_be32(&ddr->ddr_zq_cntl, regs->ddr_zq_cntl);
 		out_be32(&ddr->ddr_wrlvl_cntl, regs->ddr_wrlvl_cntl);
 		out_be32(&ddr->sdram_cfg_2, regs->ddr_sdram_cfg_2);
-		out_be32(&ddr->debug[12], 0x0);
-		out_be32(&ddr->debug[21], 0x0);
+		out_be32(&ddr->debug[12], save1);
+		out_be32(&ddr->debug[21], save2);
 		out_be32(&ddr->sdram_interval, regs->ddr_sdram_interval);
 
 	}
-- 
1.7.9.5