allwinner: H616: Add reserved-memory node to DT

When the BL31 for the Allwinner H616 runs in DRAM, we need to make sure
we tell the non-secure world about the memory region it uses.

Add a reserved-memory node to the DT, which covers the area that BL31
could occupy. The "no-map" property will prevent OSes from mapping
the area, so there would be no speculative accesses.

Change-Id: I808f3e1a8089da53bbe4fc6435a808e9159831e1
Signed-off-by: Andre Przywara <andre.przywara@arm.com>

plat/allwinner/common/include/sunxi_private.h

@@ -41,4 +41,12 @@ void sunxi_set_gpio_out(char port, int pin, bool level_high);
 int sunxi_init_platform_r_twi(uint16_t socid, bool use_rsb);
 void sunxi_execute_arisc_code(uint32_t *code, size_t size, uint16_t param);
 
+#ifdef SUNXI_BL31_IN_DRAM
+void sunxi_prepare_dtb(void *fdt);
+#else
+static inline void sunxi_prepare_dtb(void *fdt)
+{
+}
+#endif
+
 #endif /* SUNXI_PRIVATE_H */

plat/allwinner/common/sunxi_bl31_setup.c

@@ -13,6 +13,8 @@
 #include <arch.h>
 #include <arch_helpers.h>
 #include <common/debug.h>
+#include <common/fdt_fixup.h>
+#include <common/fdt_wrappers.h>
 #include <drivers/arm/gicv2.h>
 #include <drivers/console.h>
 #include <drivers/generic_delay_timer.h>
@@ -175,6 +177,8 @@ void bl31_platform_setup(void)
 
 	sunxi_pmic_setup(soc_id, fdt);
 
+	sunxi_prepare_dtb(fdt);
+
 	INFO("BL31: Platform setup done\n");
 }
 

plat/allwinner/common/sunxi_common.c

@@ -26,7 +26,7 @@ static const mmap_region_t sunxi_mmap[PLATFORM_MMAP_REGIONS + 1] = {
 	MAP_REGION(SUNXI_DRAM_BASE, SUNXI_DRAM_VIRT_BASE, SUNXI_DRAM_SEC_SIZE,
 		   MT_RW_DATA | MT_SECURE),
 	MAP_REGION(PRELOADED_BL33_BASE, SUNXI_BL33_VIRT_BASE,
-		   SUNXI_DRAM_MAP_SIZE, MT_RO_DATA | MT_NS),
+		   SUNXI_DRAM_MAP_SIZE, MT_RW_DATA | MT_NS),
 	{},
 };
 

plat/allwinner/sun50i_h616/platform.mk

@@ -17,6 +17,8 @@ ifeq (${SUNXI_PSCI_USE_SCPI}, 1)
 endif
 
 BL31_SOURCES		+=	drivers/allwinner/axp/axp805.c		\
-				drivers/allwinner/sunxi_rsb.c
+				drivers/allwinner/sunxi_rsb.c		\
+				common/fdt_fixup.c			\
+				${AW_PLAT}/${PLAT}/prepare_dtb.c
 
 $(eval $(call add_define,SUNXI_BL31_IN_DRAM))

plat/allwinner/sun50i_h616/prepare_dtb.c

@@ -0,0 +1,43 @@
+/*
+ * Copyright (c) 2021, ARM Limited. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <libfdt.h>
+
+#include <common/debug.h>
+#include <common/fdt_fixup.h>
+#include <common/fdt_wrappers.h>
+
+#include <sunxi_private.h>
+
+void sunxi_prepare_dtb(void *fdt)
+{
+	int ret;
+
+	if (fdt == NULL || fdt_check_header(fdt) != 0) {
+		return;
+	}
+	ret = fdt_open_into(fdt, fdt, 0x100000);
+	if (ret < 0) {
+		ERROR("Preparing devicetree at %p: error %d\n", fdt, ret);
+		return;
+	}
+
+	/* Reserve memory used by Trusted Firmware. */
+	if (fdt_add_reserved_memory(fdt, "tf-a@40000000", BL31_BASE,
+				    BL31_LIMIT - BL31_BASE)) {
+		WARN("Failed to add reserved memory nodes to DT.\n");
+		return;
+	}
+
+	ret = fdt_pack(fdt);
+	if (ret < 0) {
+		ERROR("Failed to pack devicetree at %p: error %d\n",
+		      fdt, ret);
+	} else {
+		clean_dcache_range((uintptr_t)fdt, fdt_blob_size(fdt));
+		INFO("Changed devicetree to reserve BL31 memory.\n");
+	}
+}