arm: mvebu: Add runtime boot-device detection

This patch adds runtime boot-device detection to SPL U-Boot.

Signed-off-by: Stefan Roese <sr@denx.de>
Cc: Luka Perkov <luka.perkov@sartura.hr>
Cc: Dirk Eibach <dirk.eibach@gdsys.cc>
Cc: Phil Sutter <phil@nwl.cc>
Cc: Kevin Smith <kevin.smith@elecsyscorp.com>

arch/arm/mach-mvebu/include/mach/soc.h

@@ -99,14 +99,24 @@
 #if defined(CONFIG_ARMADA_38X)
 /* SAR values for Armada 38x */
 #define CONFIG_SAR_REG		(MVEBU_REGISTER(0x18600))
+
 #define SAR_CPU_FREQ_OFFS	10
 #define SAR_CPU_FREQ_MASK	(0x1f << SAR_CPU_FREQ_OFFS)
 #define SAR_BOOT_DEVICE_OFFS	4
 #define SAR_BOOT_DEVICE_MASK	(0x1f << SAR_BOOT_DEVICE_OFFS)
+
+#define BOOT_DEV_SEL_OFFS	4
+#define BOOT_DEV_SEL_MASK	(0x1f << BOOT_DEV_SEL_OFFS)
+
+#define BOOT_FROM_UART		0x28
+#define BOOT_FROM_SPI		0x32
+#define BOOT_FROM_MMC		0x30
+#define BOOT_FROM_MMC_ALT	0x31
 #else
 /* SAR values for Armada XP */
 #define CONFIG_SAR_REG		(MVEBU_REGISTER(0x18230))
 #define CONFIG_SAR2_REG		(MVEBU_REGISTER(0x18234))
+
 #define SAR_CPU_FREQ_OFFS	21
 #define SAR_CPU_FREQ_MASK	(0x7 << SAR_CPU_FREQ_OFFS)
 #define SAR_FFC_FREQ_OFFS	24
@@ -115,6 +125,12 @@
 #define SAR2_CPU_FREQ_MASK	(0x1 << SAR2_CPU_FREQ_OFFS)
 #define SAR_BOOT_DEVICE_OFFS	5
 #define SAR_BOOT_DEVICE_MASK	(0xf << SAR_BOOT_DEVICE_OFFS)
+
+#define BOOT_DEV_SEL_OFFS	5
+#define BOOT_DEV_SEL_MASK	(0xf << BOOT_DEV_SEL_OFFS)
+
+#define BOOT_FROM_UART		0x2
+#define BOOT_FROM_SPI		0x3
 #endif
 
 #endif /* _MVEBU_SOC_H */

arch/arm/mach-mvebu/spl.c

@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2014-2015 Stefan Roese <sr@denx.de>
+ * Copyright (C) 2014-2016 Stefan Roese <sr@denx.de>
  *
  * SPDX-License-Identifier:	GPL-2.0+
  */
@@ -15,14 +15,30 @@
 
 DECLARE_GLOBAL_DATA_PTR;
 
-u32 spl_boot_device(void)
+static u32 get_boot_device(void)
 {
-#if defined(CONFIG_SPL_SPI_FLASH_SUPPORT)
-	return BOOT_DEVICE_SPI;
-#endif
-#if defined(CONFIG_SPL_MMC_SUPPORT)
-	return BOOT_DEVICE_MMC1;
+	u32 val;
+	u32 boot_device;
+
+	val = readl(CONFIG_SAR_REG);	/* SAR - Sample At Reset */
+	boot_device = (val & BOOT_DEV_SEL_MASK) >> BOOT_DEV_SEL_OFFS;
+	switch (boot_device) {
+#ifdef CONFIG_SPL_MMC_SUPPORT
+	case BOOT_FROM_MMC:
+	case BOOT_FROM_MMC_ALT:
+		return BOOT_DEVICE_MMC1;
 #endif
+	case BOOT_FROM_UART:
+		return BOOT_DEVICE_UART;
+	case BOOT_FROM_SPI:
+	default:
+		return BOOT_DEVICE_SPI;
+	};
+}
+
+u32 spl_boot_device(void)
+{
+	return get_boot_device();
 }
 
 #ifdef CONFIG_SPL_MMC_SUPPORT