board: sifive: support spl multi-dtb on unmatched board

There are two revisions of unmatched board with different DDR timing,
we'd like to support multi-dtb mechanism in SPL, then it selects the
right DTB at runtime according to PCB revision in I2C EEPROM.

Signed-off-by: Zong Li <zong.li@sifive.com>
Reviewed-by: Leo Yu-Chi Liang <ycliang@andestech.com>

board/sifive/unmatched/spl.c

@@ -10,11 +10,14 @@
 #include <spl.h>
 #include <misc.h>
 #include <log.h>
+#include <fdtdec.h>
+#include <dm/root.h>
 #include <linux/delay.h>
 #include <linux/io.h>
 #include <asm/gpio.h>
 #include <asm/arch/gpio.h>
 #include <asm/arch/spl.h>
+#include <asm/arch/eeprom.h>
 
 #define GEM_PHY_RESET	SIFIVE_GENERIC_GPIO_NR(0, 12)
 
@@ -26,6 +29,16 @@ int spl_board_init_f(void)
 {
 	int ret;
 
+#if defined(CONFIG_SPL_BUILD) && defined(CONFIG_SPL_MULTI_DTB_FIT)
+	int rescan;
+
+	ret = fdtdec_resetup(&rescan);
+	if (!ret && rescan) {
+		dm_uninit();
+		dm_init_and_scan(true);
+	}
+#endif
+
 	ret = spl_soc_init();
 	if (ret) {
 		debug("HiFive Unmatched FU740 SPL init failed: %d\n", ret);
@@ -79,7 +92,18 @@ u32 spl_boot_device(void)
 #ifdef CONFIG_SPL_LOAD_FIT
 int board_fit_config_name_match(const char *name)
 {
-	/* boot using first FIT config */
-	return 0;
+	/*
+	 * Apply different DDR params on different board revision.
+	 * Use PCB revision which is byte 0x7 in I2C platform EEPROM
+	 * to distinguish that.
+	 */
+	if (get_pcb_revision_from_eeprom() == PCB_REVISION_REV3 &&
+	    !strcmp(name, "hifive-unmatched-a00"))
+		return 0;
+	else if (get_pcb_revision_from_eeprom() != PCB_REVISION_REV3 &&
+		 !strcmp(name, "hifive-unmatched-a00-rev1"))
+		return 0;
+
+	return -1;
 }
 #endif

configs/sifive_unmatched_defconfig

@@ -41,3 +41,7 @@ CONFIG_USB=y
 CONFIG_DM_USB=y
 CONFIG_USB_XHCI_HCD=y
 CONFIG_USB_XHCI_PCI=y
+CONFIG_SPL_MULTI_DTB_FIT=y
+CONFIG_SPL_MULTI_DTB_FIT_NO_COMPRESSION=y
+CONFIG_SPL_OF_LIST="hifive-unmatched-a00 hifive-unmatched-a00-rev1"
+CONFIG_SPL_SYS_MALLOC_F_LEN=0x100000