rockchip: add an fdt parsing stub for platform param

The Rockchip ATF platform can be entered from both Coreboot and U-Boot.
While Coreboot does submit the list of linked parameter structs as
platform param, upstream u-boot actually always provides a pointer
to a devicetree as parameter.
This results in current ATF not running at all when started from U-Boot.

To fix this, add a stub that checks if the parameter is a fdt so we
can at least boot and not get stuck. Later on we can extend this with
actual parsing of information from the devicetree.

Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Cc: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
diff --git a/plat/rockchip/common/params_setup.c b/plat/rockchip/common/params_setup.c
index 3d1b40b..dda98d9 100644
--- a/plat/rockchip/common/params_setup.c
+++ b/plat/rockchip/common/params_setup.c
@@ -11,6 +11,7 @@
 #include <common/debug.h>
 #include <drivers/console.h>
 #include <drivers/gpio.h>
+#include <libfdt.h>
 #include <lib/coreboot.h>
 #include <lib/mmio.h>
 #include <plat/common/platform.h>
@@ -27,6 +28,13 @@
 uint32_t suspend_gpio_cnt;
 static struct apio_info *suspend_apio;
 
+static uint8_t fdt_buffer[0x10000];
+
+void *plat_get_fdt(void)
+{
+	return &fdt_buffer[0];
+}
+
 struct gpio_info *plat_get_rockchip_gpio_reset(void)
 {
 	return rst_gpio;
@@ -49,11 +57,30 @@
 	return suspend_apio;
 }
 
+static int dt_process_fdt(void *blob)
+{
+	void *fdt = plat_get_fdt();
+	int ret;
+
+	ret = fdt_open_into(blob, fdt, 0x10000);
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
 void params_early_setup(void *plat_param_from_bl2)
 {
 	struct bl31_plat_param *bl2_param;
 	struct bl31_gpio_param *gpio_param;
 
+	/*
+	 * Test if this is a FDT passed as a platform-specific parameter
+	 * block.
+	 */
+	if (!dt_process_fdt(plat_param_from_bl2))
+		return;
+
 	/* keep plat parameters for later processing if need */
 	bl2_param = (struct bl31_plat_param *)plat_param_from_bl2;
 	while (bl2_param) {