[U-Boot] [PATCH 2/2] sunxi/spl: Detect at runtime where from SPL was read

[Daniel Kochmański]

Make possible using single `u-boot-sunxi-with-spl.bin` binary for both
NAND memory and SD card. Detection where SPL was read from is
implemented in `spl_boot_device`.

Detection is performed only if `SPL_NAND_SUPPORT` is enabled. Unless
SD card contains valid signature we assume, that SPL was read from
NAND.

V2:
- Move signature verification to helper function
- Avoid unnecessary condition nesting

Signed-off-by: Daniel Kochmański <dkochmanski at turtle-solutions.eu>
CC: Roy Spliet <r.spliet at ultimaker.com>
Cc: Ian Campbell <ijc at hellion.org.uk>
Cc: Hans De Goede <hdegoede at redhat.com>
---
 arch/arm/cpu/armv7/sunxi/board.c | 46 +++++++++++++++++++++++-----------------
 include/configs/sunxi-common.h   |  2 --
 2 files changed, 26 insertions(+), 22 deletions(-)

diff --git a/arch/arm/cpu/armv7/sunxi/board.c b/arch/arm/cpu/armv7/sunxi/board.c
index 70f413f..b98fb51 100644
--- a/arch/arm/cpu/armv7/sunxi/board.c
+++ b/arch/arm/cpu/armv7/sunxi/board.c
@@ -11,6 +11,7 @@
  */
 
 #include <common.h>
+#include <mmc.h>
 #include <i2c.h>
 #include <serial.h>
 #ifdef CONFIG_SPL_BUILD
@@ -22,6 +23,7 @@
 #include <asm/arch/gpio.h>
 #include <asm/arch/sys_proto.h>
 #include <asm/arch/timer.h>
+#include <asm/arch/mmc.h>
 
 #include <linux/compiler.h>
 
@@ -109,12 +111,10 @@ void s_init(void)
 }
 
 #ifdef CONFIG_SPL_BUILD
+DECLARE_GLOBAL_DATA_PTR;
+
 /* The sunxi internal brom will try to loader external bootloader
  * from mmc0, nand flash, mmc2.
- *
- * Unfortunately we can't check how SPL was loaded so assume it's
- * always the first SD/MMC controller, unless it was explicitly
- * stated that SPL is on nand flash.
  */
 u32 spl_boot_device(void)
 {
@@ -124,17 +124,13 @@ u32 spl_boot_device(void)
 	 * enabled build. It has many restrictions and can only boot over USB.
 	 */
 	return BOOT_DEVICE_BOARD;
-#elif defined(CONFIG_SPL_NAND_SUPPORT)
-	/*
-	 * This is compile time configuration informing SPL, that it
-	 * was loaded from nand flash.
-	 */
-	return BOOT_DEVICE_NAND;
 #else
+	__maybe_unused struct mmc *mmc0;
+
 	/*
-	 * When booting from the SD card, the "eGON.BT0" signature is expected
-	 * to be found in memory at the address 0x0004 (see the "mksunxiboot"
-	 * tool, which generates this header).
+	 * When booting from the SD card or NAND memory, the "eGON.BT0"
+	 * signature is expected to be found in memory at the address 0x0004
+	 * (see the "mksunxiboot" tool, which generates this header).
 	 *
 	 * When booting in the FEL mode over USB, this signature is patched in
 	 * memory and replaced with something else by the 'fel' tool. This other
@@ -142,15 +138,25 @@ u32 spl_boot_device(void)
 	 * valid bootable SD card image (because the BROM would refuse to
 	 * execute the SPL in this case).
 	 *
-	 * This branch is just making a decision at runtime whether to load
-	 * the main u-boot binary from the SD card (if the "eGON.BT0" signature
-	 * is found) or return to the FEL code in the BROM to wait and receive
-	 * the main u-boot binary over USB.
+	 * This checks for the signature and if it is not found returns to
+	 * the FEL code in the BROM to wait and receive the main u-boot
+	 * binary over USB. If it is found, it determines where SPL was
+	 * read from.
 	 */
-	if (readl(4) == 0x4E4F4765 && readl(8) == 0x3054422E) /* eGON.BT0 */
-		return BOOT_DEVICE_MMC1;
-	else
+	if (readl(4) != 0x4E4F4765 || readl(8) != 0x3054422E) /* eGON.BT0 */
 		return BOOT_DEVICE_BOARD;
+
+	/* If NAND isn't enabled, then we boot either from mmc0 or mmc2. */
+	if (!IS_ENABLED(CONFIG_SPL_NAND_SUPPORT))
+		return BOOT_DEVICE_MMC1;
+
+	/* The BROM will try to boot from mmc0 first, so try that first. */
+	mmc_initialize(gd->bd);
+	mmc0 = find_mmc_device(0);
+	if (sunxi_mmc_has_egon_boot_signature(mmc0))
+		return BOOT_DEVICE_MMC1;
+
+	return BOOT_DEVICE_NAND;
 #endif
 }
 
diff --git a/include/configs/sunxi-common.h b/include/configs/sunxi-common.h
index cce0441..e4db777 100644
--- a/include/configs/sunxi-common.h
+++ b/include/configs/sunxi-common.h
@@ -106,10 +106,8 @@
 #define CONFIG_CMD_MMC
 #define CONFIG_MMC_SUNXI
 #define CONFIG_MMC_SUNXI_SLOT		0
-#if !defined(CONFIG_SPL_NAND_SUPPORT)
 #define CONFIG_ENV_IS_IN_MMC
 #define CONFIG_SYS_MMC_ENV_DEV		0	/* first detected MMC controller */
-#endif /* CONFIG_SPL_NAND_SUPPORT */
 #endif
 
 /* 4MB of malloc() pool */
-- 
2.4.1