mpc8xxx: set x2 DDR3 refresh rate if SPD config requires it

If the DDR3 module supports industrial temperature range and requires
the x2 refresh rate for that temp range, the refresh period must be
3.9us instead of 7.8 us.

This was successfuly tested on kmp204x board with some MT41K128M16 DDR3
RAM chips (no module used, chips directly soldered on board with an SPD
EEPROM).

Signed-off-by: Valentin Longchamp <valentin.longchamp@keymile.com>
[York Sun: fix minor conflicts in fsl_ddr_dimm_params.h,
	   lc_common_dimm_params.c, common_timing_params.h]
Acked-by: York Sun <yorksun@freescale.com>

arch/powerpc/cpu/mpc8xxx/ddr/common_timing_params.h

@@ -28,6 +28,7 @@ typedef struct {
 	unsigned int trc_ps;	/* maximum = 254 ns + .75 ns = 254750 ps */
 
 	unsigned int refresh_rate_ps;
+	unsigned int extended_op_srt;
 
 	unsigned int tis_ps;	/* byte 32, spd->ca_setup */
 	unsigned int tih_ps;	/* byte 33, spd->ca_hold */

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

@@ -765,6 +765,7 @@ static void set_ddr_sdram_cfg_2(fsl_ddr_cfg_regs_t *ddr,
 /* DDR SDRAM Mode configuration 2 (DDR_SDRAM_MODE_2) */
 static void set_ddr_sdram_mode_2(fsl_ddr_cfg_regs_t *ddr,
 				const memctl_options_t *popts,
+				const common_timing_params_t *common_dimm,
 				const unsigned int unq_mrs_en)
 {
 	unsigned short esdmode2 = 0;	/* Extended SDRAM mode 2 */
@@ -782,6 +783,10 @@ static void set_ddr_sdram_mode_2(fsl_ddr_cfg_regs_t *ddr,
 		rtt_wr = popts->rtt_wr_override_value;
 	else
 		rtt_wr = popts->cs_local_opts[0].odt_rtt_wr;
+
+	if (common_dimm->extended_op_srt)
+		srt = common_dimm->extended_op_srt;
+
 	esdmode2 = (0
 		| ((rtt_wr & 0x3) << 9)
 		| ((srt & 0x1) << 7)
@@ -1626,7 +1631,7 @@ compute_fsl_memctl_config_regs(const memctl_options_t *popts,
 	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);
-	set_ddr_sdram_mode_2(ddr, popts, unq_mrs_en);
+	set_ddr_sdram_mode_2(ddr, popts, common_dimm, unq_mrs_en);
 	set_ddr_sdram_interval(ddr, popts, common_dimm);
 	set_ddr_data_init(ddr);
 	set_ddr_sdram_clk_cntl(ddr, popts);

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

@@ -321,6 +321,10 @@ ddr_compute_dimm_parameters(const ddr3_spd_eeprom_t *spd,
 	 *       = 3.9 us at ext temperature range
 	 */
 	pdimm->refresh_rate_ps = 7800000;
+	if ((spd->therm_ref_opt & 0x1) && !(spd->therm_ref_opt & 0x2)) {
+		pdimm->refresh_rate_ps = 3900000;
+		pdimm->extended_op_srt = 1;
+	}
 
 	/*
 	 * min four active window delay time

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

@@ -92,6 +92,7 @@ compute_lowest_common_dimm_parameters(const dimm_params_t *dimm_params,
 	unsigned int trrd_ps = 0;
 	unsigned int trc_ps = 0;
 	unsigned int refresh_rate_ps = 0;
+	unsigned int extended_op_srt = 1;
 	unsigned int tis_ps = 0;
 	unsigned int tih_ps = 0;
 	unsigned int tds_ps = 0;
@@ -166,6 +167,9 @@ compute_lowest_common_dimm_parameters(const dimm_params_t *dimm_params,
 		tqhs_ps = max(tqhs_ps, dimm_params[i].tqhs_ps);
 		refresh_rate_ps = max(refresh_rate_ps,
 				      dimm_params[i].refresh_rate_ps);
+		/* extended_op_srt is either 0 or 1, 0 having priority */
+		extended_op_srt = min(extended_op_srt,
+				      dimm_params[i].extended_op_srt);
 
 		/*
 		 * Find maximum tdqsq_max_ps to find slowest.
@@ -195,6 +199,7 @@ compute_lowest_common_dimm_parameters(const dimm_params_t *dimm_params,
 	outpdimm->trrd_ps = trrd_ps;
 	outpdimm->trc_ps = trc_ps;
 	outpdimm->refresh_rate_ps = refresh_rate_ps;
+	outpdimm->extended_op_srt = extended_op_srt;
 	outpdimm->tis_ps = tis_ps;
 	outpdimm->tih_ps = tih_ps;
 	outpdimm->tds_ps = tds_ps;

arch/powerpc/include/asm/fsl_ddr_dimm_params.h

@@ -78,6 +78,7 @@ typedef struct dimm_params_s {
 	unsigned int trc_ps;	/* maximum = 254 ns + .75 ns = 254750 ps */
 
 	unsigned int refresh_rate_ps;
+	unsigned int extended_op_srt;
 
 	/* DDR3 doesn't need these as below */
 	unsigned int tis_ps;	/* byte 32, spd->ca_setup */