MPC83xx: add config options for memory setup.

CPO value and driver strength settings are board specifc.
Also allow SPD data fetch from any accessible I2C EEPROM.

Signed-off-by: Andre Schwarz <andre.schwarz@matrix-vision.de>
Acked-by: York Sun <yorksun@freescale.com>
Signed-off-by: Kim Phillips <kim.phillips@freescale.com>
diff --git a/arch/powerpc/cpu/mpc83xx/spd_sdram.c b/arch/powerpc/cpu/mpc83xx/spd_sdram.c
index 44aaa9a..9b01f0d 100644
--- a/arch/powerpc/cpu/mpc83xx/spd_sdram.c
+++ b/arch/powerpc/cpu/mpc83xx/spd_sdram.c
@@ -68,6 +68,12 @@
 #ifndef	CONFIG_SYS_READ_SPD
 #define CONFIG_SYS_READ_SPD	i2c_read
 #endif
+#ifndef SPD_EEPROM_OFFSET
+#define SPD_EEPROM_OFFSET	0
+#endif
+#ifndef SPD_EEPROM_ADDR_LEN
+#define SPD_EEPROM_ADDR_LEN     1
+#endif
 
 /*
  * Convert picoseconds into clock cycles (rounding up if needed).
@@ -160,7 +166,8 @@
 	isync();
 
 	/* Read SPD parameters with I2C */
-	CONFIG_SYS_READ_SPD(SPD_EEPROM_ADDRESS, 0, 1, (uchar *) & spd, sizeof (spd));
+	CONFIG_SYS_READ_SPD(SPD_EEPROM_ADDRESS, SPD_EEPROM_OFFSET,
+		SPD_EEPROM_ADDR_LEN, (uchar *) &spd, sizeof(spd));
 #ifdef SPD_DEBUG
 	spd_debug(&spd);
 #endif
@@ -562,6 +569,9 @@
 	 * Empirically, 0x3 == 6/8 clock delay is suggested for DDR I 266.
 	 */
 	wr_data_delay = 2;
+#ifdef CONFIG_SYS_DDR_WRITE_DATA_DELAY
+	wr_data_delay = CONFIG_SYS_DDR_WRITE_DATA_DELAY;
+#endif
 
 	/*
 	 * Write Latency
@@ -601,6 +611,9 @@
 	 */
 	cpo = 0;
 	if (spd.mem_type == SPD_MEMTYPE_DDR2) {
+#ifdef CONFIG_SYS_DDR_CPO
+		cpo = CONFIG_SYS_DDR_CPO;
+#else
 		if (effective_data_rate == 266) {
 			cpo = 0x4;		/* READ_LAT + 1/2 */
 		} else if (effective_data_rate == 333) {
@@ -611,6 +624,7 @@
 			/* Automatic calibration */
 			cpo = 0x1f;
 		}
+#endif
 	}
 
 	ddr->timing_cfg_2 = (0
@@ -679,6 +693,9 @@
 		ddr->sdram_mode =
 			(0
 			 | (1 << (16 + 10))             /* DQS Differential disable */
+#ifdef CONFIG_SYS_DDR_MODE_WEAK
+			 | (1 << (16 + 1))		/* weak driver (~60%) */
+#endif
 			 | (add_lat << (16 + 3))        /* Additive Latency in EMRS1 */
 			 | (mode_odt_enable << 16)      /* ODT Enable in EMRS1 */
 			 | ((twr_clk - 1) << 9)         /* Write Recovery Autopre */