fix(zynqmp): conditional reservation of memory in DTB

When the TF-A is placed in DDR memory range, the DDR memory range is
getting explicitly reserved in the default device tree by TF-A.
This creates an error condition in the use case where Device tree is
not present or it is present at a different location.

To fix this, a new build time parameter, XILINX_OF_BOARD_DTB_ADDR, is
introduced. The TF-A will reserve the DDR memory only when a valid
DTB address is provided to XILINX_OF_BOARD_DTB_ADDR during build.

Now the user has options, either manually reserve the desired
DDR address range for TF-A in device tree or let TF-A access and modify
the device tree, to reserve the DDR address range, in runtime using
the build parameter.

Change-Id: I846fa373ba9f7c984eda3a55ccaaa622082cad81
Signed-off-by: Akshay Belsare <akshay.belsare@amd.com>

docs/plat/xilinx-zynqmp.rst

@@ -31,6 +31,7 @@ To build TF-A for JTAG DCC console:
 ZynqMP platform specific build options
 --------------------------------------
 
+-  ``XILINX_OF_BOARD_DTB_ADDR`` : Specifies the base address of Device tree.
 -  ``ZYNQMP_ATF_MEM_BASE``: Specifies the base address of the bl31 binary.
 -  ``ZYNQMP_ATF_MEM_SIZE``: Specifies the size of the memory region of the bl31 binary.
 -  ``ZYNQMP_BL32_MEM_BASE``: Specifies the base address of the bl32 binary.
@@ -47,13 +48,33 @@ ZynqMP Debug behavior
 With DEBUG=1, TF-A for ZynqMP uses DDR memory range instead of OCM memory range
 due to size constraints.
 For DEBUG=1 configuration for ZynqMP the BL31_BASE is set to the DDR location
-of 0x1000 and BL31_LIMIT is set to DDR location of 0x7FFFF.
+of 0x1000 and BL31_LIMIT is set to DDR location of 0x7FFFF. By default the
+above memory range will NOT be reserved in device tree.
 
-If the user wants to move the bl31 to a different DDR location, user can provide
+To reserve the above memory range in device tree, the device tree base address
-the DDR address location in the build command as follows,
+must be provided during build as,
 
 make CROSS_COMPILE=aarch64-none-elf- PLAT=zynqmp RESET_TO_BL31=1 DEBUG=1 \
-	ZYNQMP_ATF_MEM_BASE=<DDR address> ZYNQMP_ATF_MEM_SIZE=<size> bl31
+       XILINX_OF_BOARD_DTB_ADDR=<DTB address> bl31
+
+The default DTB base address for ZynqMP platform is 0x100000. This default value
+is not set in the code and to use this default address, user still needs to
+provide it through the build command as above.
+
+If the user wants to move the bl31 to a different DDR location, user can provide
+the DDR address location using the build time parameters ZYNQMP_ATF_MEM_BASE and
+ZYNQMP_ATF_MEM_SIZE.
+
+The DDR address must be reserved in the DTB by the user, either by manually
+adding the reserved memory node, in the device tree, with the required address
+range OR let TF-A modify the device tree on the run.
+
+To let TF-A access and modify the device tree, the DTB address must be provided
+to the build command as follows,
+
+make CROSS_COMPILE=aarch64-none-elf- PLAT=zynqmp RESET_TO_BL31=1 DEBUG=1 \
+	ZYNQMP_ATF_MEM_BASE=<DDR address> ZYNQMP_ATF_MEM_SIZE=<size> \
+	XILINX_OF_BOARD_DTB_ADDR=<DTB address> bl31
 
 
 FSBL->TF-A Parameter Passing

plat/xilinx/zynqmp/bl31_zynqmp_setup.c

@@ -171,7 +171,7 @@ static uint64_t rdo_el3_interrupt_handler(uint32_t id, uint32_t flags,
 }
 #endif
 
-#if (BL31_LIMIT < PLAT_DDR_LOWMEM_MAX)
+#if (defined(XILINX_OF_BOARD_DTB_ADDR) && !IS_TFA_IN_OCM(BL31_BASE))
 static void prepare_dtb(void)
 {
 	void *dtb = (void *)XILINX_OF_BOARD_DTB_ADDR;
@@ -217,7 +217,7 @@ static void prepare_dtb(void)
 
 void bl31_platform_setup(void)
 {
-#if (BL31_LIMIT < PLAT_DDR_LOWMEM_MAX)
+#if (defined(XILINX_OF_BOARD_DTB_ADDR) && !IS_TFA_IN_OCM(BL31_BASE))
 	prepare_dtb();
 #endif
 
@@ -250,7 +250,7 @@ void bl31_plat_arch_setup(void)
 	plat_arm_interconnect_enter_coherency();
 
 	const mmap_region_t bl_regions[] = {
-#if (BL31_LIMIT < PLAT_DDR_LOWMEM_MAX)
+#if (defined(XILINX_OF_BOARD_DTB_ADDR) && !IS_TFA_IN_OCM(BL31_BASE))
 		MAP_REGION_FLAT(XILINX_OF_BOARD_DTB_ADDR, XILINX_OF_BOARD_DTB_MAX_SIZE,
 			MT_MEMORY | MT_RW | MT_NS),
 #endif

plat/xilinx/zynqmp/include/platform_def.h

@@ -1,5 +1,7 @@
 /*
  * Copyright (c) 2014-2022, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2018-2022, Xilinx, Inc. All rights reserved.
+ * Copyright (c) 2022-2023, Advanced Micro Devices, Inc. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -83,15 +85,18 @@
 /*******************************************************************************
  * Platform specific page table and MMU setup constants
  ******************************************************************************/
-#define XILINX_OF_BOARD_DTB_ADDR	U(0x100000)
 #define XILINX_OF_BOARD_DTB_MAX_SIZE	U(0x200000)
 #define PLAT_DDR_LOWMEM_MAX		U(0x80000000)
+#define PLAT_OCM_BASE			U(0xFFFC0000)
+#define PLAT_OCM_LIMIT			U(0xFFFFFFFF)
+
+#define IS_TFA_IN_OCM(x)		((x >= PLAT_OCM_BASE) && (x < PLAT_OCM_LIMIT))
 
 #define PLAT_PHY_ADDR_SPACE_SIZE	(1ULL << 32)
 #define PLAT_VIRT_ADDR_SPACE_SIZE	(1ULL << 32)
 
 #ifndef MAX_MMAP_REGIONS
-#if (BL31_LIMIT < PLAT_DDR_LOWMEM_MAX)
+#if (defined(XILINX_OF_BOARD_DTB_ADDR) && !IS_TFA_IN_OCM(BL31_BASE))
 #define MAX_MMAP_REGIONS		8
 #else
 #define MAX_MMAP_REGIONS		7
@@ -99,7 +104,7 @@
 #endif
 
 #ifndef MAX_XLAT_TABLES
-#if (BL31_LIMIT < PLAT_DDR_LOWMEM_MAX)
+#if !IS_TFA_IN_OCM(BL31_BASE)
 #define MAX_XLAT_TABLES			8
 #else
 #define MAX_XLAT_TABLES			5

plat/xilinx/zynqmp/platform.mk

@@ -1,6 +1,8 @@
 #
 # Copyright (c) 2013-2021, ARM Limited and Contributors. All rights reserved.
 # Portions copyright (c) 2021-2022, ProvenRun S.A.S. All rights reserved.
+# Copyright (c) 2018-2022, Xilinx, Inc. All rights reserved.
+# Copyright (c) 2022-2023, Advanced Micro Devices, Inc. All rights reserved.
 #
 # SPDX-License-Identifier: BSD-3-Clause
 
@@ -75,6 +77,10 @@ ifdef ZYNQMP_SECURE_EFUSES
     $(eval $(call add_define,ZYNQMP_SECURE_EFUSES))
 endif
 
+ifdef XILINX_OF_BOARD_DTB_ADDR
+$(eval $(call add_define,XILINX_OF_BOARD_DTB_ADDR))
+endif
+
 PLAT_INCLUDES		:=	-Iinclude/plat/arm/common/			\
 				-Iinclude/plat/arm/common/aarch64/		\
 				-Iplat/xilinx/common/include/			\