rockchip: rk3399: inject 'u-boot, spl-boot-device' for next-stage

This implements the new 'spl_perform_fixups' hook for RK3399-based
boards and injects the /chosen/u-boot,spl-boot-device with an ofpath
corresponding to the boot device used.

The intended usage is for the full U-Boot stage to evaluate this in
scripts and then adapt its boot-order when using distro-boot.

Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Tested-by: Klaus Goger <klaus.goger@theobroma-systems.com>

arch/arm/mach-rockchip/rk3399-board-spl.c

@@ -57,6 +57,54 @@ u32 spl_boot_device(void)
 	return boot_device;
 }
 
+const char *spl_decode_boot_device(u32 boot_device)
+{
+	int i;
+	static const struct {
+		u32 boot_device;
+		const char *ofpath;
+	} spl_boot_devices_tbl[] = {
+		{ BOOT_DEVICE_MMC1, "/dwmmc@fe320000" },
+		{ BOOT_DEVICE_MMC2, "/sdhci@fe330000" },
+		{ BOOT_DEVICE_SPI, "/spi@ff1d0000" },
+	};
+
+	for (i = 0; i < ARRAY_SIZE(spl_boot_devices_tbl); ++i)
+		if (spl_boot_devices_tbl[i].boot_device == boot_device)
+			return spl_boot_devices_tbl[i].ofpath;
+
+	return NULL;
+}
+
+void spl_perform_fixups(struct spl_image_info *spl_image)
+{
+	void *blob = spl_image->fdt_addr;
+	const char *boot_ofpath;
+	int chosen;
+
+	/*
+	 * Inject the ofpath of the device the full U-Boot (or Linux in
+	 * Falcon-mode) was booted from into the FDT, if a FDT has been
+	 * loaded at the same time.
+	 */
+	if (!blob)
+		return;
+
+	boot_ofpath = spl_decode_boot_device(spl_image->boot_device);
+	if (!boot_ofpath) {
+		pr_err("%s: could not map boot_device to ofpath\n", __func__);
+		return;
+	}
+
+	chosen = fdt_find_or_add_subnode(blob, 0, "chosen");
+	if (chosen < 0) {
+		pr_err("%s: could not find/create '/chosen'\n", __func__);
+		return;
+	}
+	fdt_setprop_string(blob, chosen,
+			   "u-boot,spl-boot-device", boot_ofpath);
+}
+
 #define TIMER_CHN10_BASE	0xff8680a0
 #define TIMER_END_COUNT_L	0x00
 #define TIMER_END_COUNT_H	0x04