[PATCH 4/7] sunxi: use boot source for determining environment location

[Andre Przywara <andre.przywara@arm.com>]

Currently we only support to load the environment from raw MMC or FAT
locations on Allwinner boards. With the advent of SPI flash we probably
also want to support using the environment there, so we need to become
a bit more flexible.

Change the environment priority function to take the boot source into
account. When booted from eMMC or SD card, we use FAT or MMC, if
configured, as before.
If we are booted from SPI flash, we try to use the environment from
there, if possible. The same is true for NAND flash booting, although
this is somewhat theoretical right now (as untested).

This way we can use the same image for SD and SPI flash booting, which
allows us to simply copy a booted image from SD card to the SPI flash,
for instance.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
---
 board/sunxi/board.c | 51 ++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 43 insertions(+), 8 deletions(-)

diff --git a/board/sunxi/board.c b/board/sunxi/board.c
index 2790a0f9e8..2472343d00 100644
--- a/board/sunxi/board.c
+++ b/board/sunxi/board.c
@@ -170,21 +170,56 @@ void i2c_init_board(void)
 #endif
 }
 
-#if defined(CONFIG_ENV_IS_IN_MMC) && defined(CONFIG_ENV_IS_IN_FAT)
+/*
+ * Try to use the environment from the boot source first.
+ * For MMC, this means a FAT partition on the boot device (SD or eMMC).
+ * If the raw MMC environment is also enabled, this is tried next.
+ * SPI flash falls back to FAT (on SD card).
+ */
 enum env_location env_get_location(enum env_operation op, int prio)
 {
-	switch (prio) {
-	case 0:
-		return ENVL_FAT;
+	enum env_location boot_loc = ENVL_FAT;
 
-	case 1:
-		return ENVL_MMC;
+	gd->env_load_prio = prio;
 
+	switch (sunxi_get_boot_device()) {
+	case BOOT_DEVICE_MMC1:
+	case BOOT_DEVICE_MMC2:
+		boot_loc = ENVL_FAT;
+		break;
+	case BOOT_DEVICE_NAND:
+		if (IS_ENABLED(CONFIG_ENV_IS_IN_NAND))
+			boot_loc = ENVL_NAND;
+		break;
+	case BOOT_DEVICE_SPI:
+		if (IS_ENABLED(CONFIG_ENV_IS_IN_SPI_FLASH))
+			boot_loc = ENVL_SPI_FLASH;
+		break;
+	case BOOT_DEVICE_BOARD:
+		break;
 	default:
-		return ENVL_UNKNOWN;
+		break;
+	}
+
+	/* Always try to access the environment on the boot device first. */
+	if (prio == 0)
+		return boot_loc;
+
+	if (prio == 1) {
+		switch (boot_loc) {
+		case ENVL_SPI_FLASH:
+			return ENVL_FAT;
+		case ENVL_FAT:
+			if (IS_ENABLED(CONFIG_ENV_IS_IN_MMC))
+				return ENVL_MMC;
+			break;
+		default:
+			break;
+		}
 	}
+
+	return ENVL_UNKNOWN;
 }
-#endif
 
 #ifdef CONFIG_DM_MMC
 static void mmc_pinmux_setup(int sdc);
-- 
2.25.1