powerpc/mpc8xxx: Add x4 DDR device support

On selected platforms, x4 DDR devices can be supported. Using x4 devices may
lower the performance, but generally they are available for higher density.

Tested on MT36JSF2G72PZ-1G9E1 RDIMM.

Signed-off-by: York Sun <yorksun@freescale.com>

arch/powerpc/cpu/mpc8xxx/ddr/ctrl_regs.c

@@ -681,6 +681,7 @@ static void set_ddr_sdram_cfg_2(fsl_ddr_cfg_regs_t *ddr,
 	unsigned int odt_cfg = 0;	/* ODT configuration */
 	unsigned int num_pr;		/* Number of posted refreshes */
 	unsigned int slow = 0;		/* DDR will be run less than 1250 */
+	unsigned int x4_en = 0;		/* x4 DRAM enable */
 	unsigned int obc_cfg;		/* On-The-Fly Burst Chop Cfg */
 	unsigned int ap_en;		/* Address Parity Enable */
 	unsigned int d_init;		/* DRAM data initialization */
@@ -725,6 +726,8 @@ static void set_ddr_sdram_cfg_2(fsl_ddr_cfg_regs_t *ddr,
 		ap_en = 0;
 	}
 
+	x4_en = popts->x4_en ? 1 : 0;
+
 #if defined(CONFIG_ECC_INIT_VIA_DDRCONTROLLER)
 	/* Use the DDR controller to auto initialize memory. */
 	d_init = popts->ECC_init_using_memctl;
@@ -747,6 +750,7 @@ static void set_ddr_sdram_cfg_2(fsl_ddr_cfg_regs_t *ddr,
 		| ((odt_cfg & 0x3) << 21)
 		| ((num_pr & 0xf) << 12)
 		| ((slow & 1) << 11)
+		| (x4_en << 10)
 		| (qd_en << 9)
 		| (unq_mrs_en << 8)
 		| ((obc_cfg & 0x1) << 6)

arch/powerpc/cpu/mpc8xxx/ddr/ddr3_dimm_params.c

@@ -129,6 +129,7 @@ ddr_compute_dimm_parameters(const ddr3_spd_eeprom_t *spd,
 		pdimm->ec_sdram_width = 0;
 	pdimm->data_width = pdimm->primary_sdram_width
 			  + pdimm->ec_sdram_width;
+	pdimm->device_width = 1 << ((spd->organization & 0x7) + 2);
 
 	/* These are the types defined by the JEDEC DDR3 SPD spec */
 	pdimm->mirrored_dimm = 0;

arch/powerpc/cpu/mpc8xxx/ddr/interactive.c

@@ -205,6 +205,7 @@ static void fsl_ddr_dimm_parameters_edit(fsl_ddr_info_t *pinfo,
 		DIMM_PARM(primary_sdram_width),
 		DIMM_PARM(ec_sdram_width),
 		DIMM_PARM(registered_dimm),
+		DIMM_PARM(device_width),
 
 		DIMM_PARM(n_row_addr),
 		DIMM_PARM(n_col_addr),
@@ -263,6 +264,7 @@ static void print_dimm_parameters(const dimm_params_t *pdimm)
 		DIMM_PARM(primary_sdram_width),
 		DIMM_PARM(ec_sdram_width),
 		DIMM_PARM(registered_dimm),
+		DIMM_PARM(device_width),
 
 		DIMM_PARM(n_row_addr),
 		DIMM_PARM(n_col_addr),
@@ -443,6 +445,7 @@ static void fsl_ddr_options_edit(fsl_ddr_info_t *pinfo,
 		CTRL_OPTIONS(twoT_en),
 		CTRL_OPTIONS(threeT_en),
 		CTRL_OPTIONS(ap_en),
+		CTRL_OPTIONS(x4_en),
 		CTRL_OPTIONS(bstopre),
 		CTRL_OPTIONS(wrlvl_override),
 		CTRL_OPTIONS(wrlvl_sample),
@@ -687,6 +690,7 @@ static void print_memctl_options(const memctl_options_t *popts)
 		CTRL_OPTIONS(threeT_en),
 		CTRL_OPTIONS(registered_dimm_en),
 		CTRL_OPTIONS(ap_en),
+		CTRL_OPTIONS(x4_en),
 		CTRL_OPTIONS(bstopre),
 		CTRL_OPTIONS(wrlvl_override),
 		CTRL_OPTIONS(wrlvl_sample),

arch/powerpc/cpu/mpc8xxx/ddr/options.c

@@ -700,6 +700,8 @@ unsigned int populate_memctl_options(int all_DIMMs_registered,
 	}
 #endif
 
+	popts->x4_en = (pdimm[0].device_width == 4) ? 1 : 0;
+
 	/* Choose burst length. */
 #if defined(CONFIG_FSL_DDR3)
 #if defined(CONFIG_E500MC)

arch/powerpc/include/asm/fsl_ddr_dimm_params.h

@@ -26,6 +26,7 @@ typedef struct dimm_params_s {
 	unsigned int primary_sdram_width;
 	unsigned int ec_sdram_width;
 	unsigned int registered_dimm;
+	unsigned int device_width;	/* x4, x8, x16 components */
 
 	/* SDRAM device parameters */
 	unsigned int n_row_addr;

arch/powerpc/include/asm/fsl_ddr_sdram.h

@@ -277,6 +277,7 @@ typedef struct memctl_options_s {
 	unsigned int mirrored_dimm;
 	unsigned int quad_rank_present;
 	unsigned int ap_en;	/* address parity enable for RDIMM */
+	unsigned int x4_en;	/* enable x4 devices */
 
 	/* Global Timing Parameters */
 	unsigned int cas_latency_override;