rockchip: spl: make spl-boot-order code reusable (split from rk3399)

In order to reuse the support for the u-boot,spl-boot-order property
from the rk3399, we split it into a reusable module that can be
included by the SPL code for any of our boards.

Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/arm/mach-rockchip/spl-boot-order.c b/arch/arm/mach-rockchip/spl-boot-order.c
new file mode 100644
index 0000000..4f78c72
--- /dev/null
+++ b/arch/arm/mach-rockchip/spl-boot-order.c
@@ -0,0 +1,108 @@
+/*
+ * (C) Copyright 2017 Theobroma Systems Design und Consulting GmbH
+ *
+ * SPDX-License-Identifier:     GPL-2.0+
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <mmc.h>
+#include <spl.h>
+
+#if CONFIG_IS_ENABLED(OF_CONTROL)
+static int spl_node_to_boot_device(int node)
+{
+	struct udevice *parent;
+
+	/*
+	 * This should eventually move into the SPL code, once SPL becomes
+	 * aware of the block-device layer.  Until then (and to avoid unneeded
+	 * delays in getting this feature out, it lives at the board-level).
+	 */
+	if (!uclass_get_device_by_of_offset(UCLASS_MMC, node, &parent)) {
+		struct udevice *dev;
+		struct blk_desc *desc = NULL;
+
+		for (device_find_first_child(parent, &dev);
+		     dev;
+		     device_find_next_child(&dev)) {
+			if (device_get_uclass_id(dev) == UCLASS_BLK) {
+				desc = dev_get_uclass_platdata(dev);
+				break;
+			}
+		}
+
+		if (!desc)
+			return -ENOENT;
+
+		switch (desc->devnum) {
+		case 0:
+			return BOOT_DEVICE_MMC1;
+		case 1:
+			return BOOT_DEVICE_MMC2;
+		default:
+			return -ENOSYS;
+		}
+	}
+
+	/*
+	 * SPL doesn't differentiate SPI flashes, so we keep the detection
+	 * brief and inaccurate... hopefully, the common SPL layer can be
+	 * extended with awareness of the BLK layer (and matching OF_CONTROL)
+	 * soon.
+	 */
+	if (!uclass_get_device_by_of_offset(UCLASS_SPI_FLASH, node, &parent))
+		return BOOT_DEVICE_SPI;
+
+	return -1;
+}
+
+void board_boot_order(u32 *spl_boot_list)
+{
+	const void *blob = gd->fdt_blob;
+	int chosen_node = fdt_path_offset(blob, "/chosen");
+	int idx = 0;
+	int elem;
+	int boot_device;
+	int node;
+	const char *conf;
+
+	if (chosen_node < 0) {
+		debug("%s: /chosen not found, using spl_boot_device()\n",
+		      __func__);
+		spl_boot_list[0] = spl_boot_device();
+		return;
+	}
+
+	for (elem = 0;
+	     (conf = fdt_stringlist_get(blob, chosen_node,
+					"u-boot,spl-boot-order", elem, NULL));
+	     elem++) {
+		/* First check if the list element is an alias */
+		const char *alias = fdt_get_alias(blob, conf);
+		if (alias)
+			conf = alias;
+
+		/* Try to resolve the config item (or alias) as a path */
+		node = fdt_path_offset(blob, conf);
+		if (node < 0) {
+			debug("%s: could not find %s in FDT", __func__, conf);
+			continue;
+		}
+
+		/* Try to map this back onto SPL boot devices */
+		boot_device = spl_node_to_boot_device(node);
+		if (boot_device < 0) {
+			debug("%s: could not map node @%x to a boot-device\n",
+			      __func__, node);
+			continue;
+		}
+
+		spl_boot_list[idx++] = boot_device;
+	}
+
+	/* If we had no matches, fall back to spl_boot_device */
+	if (idx == 0)
+		spl_boot_list[0] = spl_boot_device();
+}
+#endif