imx: spl: implement spl_boot_mode for i.MX7/8/8M

It will be easy to separate SD/EMMC when booting in SPL stage, then
no need to bother which device is BOOT_DEVICE_MMC1/2.
Signed-off-by: Peng Fan <peng.fan@nxp.com>

arch/arm/mach-imx/spl.c

@@ -189,6 +189,34 @@ int g_dnl_bind_fixup(struct usb_device_descriptor *dev, const char *name)
 /* called from spl_mmc to see type of boot mode for storage (RAW or FAT) */
 u32 spl_boot_mode(const u32 boot_device)
 {
+#if defined(CONFIG_MX7) || defined(CONFIG_IMX8M) || defined(CONFIG_IMX8)
+	switch (get_boot_device()) {
+	/* for MMC return either RAW or FAT mode */
+	case SD1_BOOT:
+	case SD2_BOOT:
+	case SD3_BOOT:
+#if defined(CONFIG_SPL_FAT_SUPPORT)
+		return MMCSD_MODE_FS;
+#else
+		return MMCSD_MODE_RAW;
+#endif
+		break;
+	case MMC1_BOOT:
+	case MMC2_BOOT:
+	case MMC3_BOOT:
+#if defined(CONFIG_SPL_FAT_SUPPORT)
+		return MMCSD_MODE_FS;
+#elif defined(CONFIG_SUPPORT_EMMC_BOOT)
+		return MMCSD_MODE_EMMCBOOT;
+#else
+		return MMCSD_MODE_RAW;
+#endif
+		break;
+	default:
+		puts("spl: ERROR:  unsupported device\n");
+		hang();
+	}
+#else
 /*
  * When CONFIG_SPL_FORCE_MMC_BOOT is defined the 'boot_device' is used
  * unconditionally to decide about device to use for booting.
@@ -217,6 +245,7 @@ u32 spl_boot_mode(const u32 boot_device)
 		puts("spl: ERROR:  unsupported device\n");
 		hang();
 	}
+#endif
 }
 #endif