ARM: arch-meson: build memory banks using reported memory from registers

As discussed at [1], the Amlogic Meson GX SoCs can embed a BL31 firmware
and a secondary BL32 firmware.
Since mid-2017, the reserved memory address of the BL31 firmware was moved
and grown for security reasons.

But mainline U-Boot and Linux has the old address and size fixed.

These SoCs have a register interface to get the two firmware reserved
memory start and sizes.

This patch adds a dynamic reservation of the memory zones in the device tree bootmem
reserved memory zone used by the kernel in early boot.
To be complete, the memory zones are also added to the EFI reserved zones.

Depends on patchset "Add support for Amlogic GXL Based SBCs" at [2].

[1] http://lists.infradead.org/pipermail/linux-amlogic/2017-October/004860.html
[2] http://lists.infradead.org/pipermail/linux-amlogic/2017-November/005410.html

Changes since v1:
- switched the #if to if(IS_ENABLED()) to compile all code paths
- renamed function to meson_board_add_reserved_memory()
- added a mem.h header with comment
- updated all boards ft_board_setup()

Changes since RFC v2:
- reduced preprocessor load
- kept Odroid-C2 static memory mapping as exception

Changes since RFC v1:
- switch to fdt rsv mem table and efi reserve memory
- replaced in_le32 by readl()

Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
[trini: Fix warning on khadas-vim over missing <asm/arch/mem.h>
Signed-off-by: Tom Rini <trini@konsulko.com>

3 files changed, 99 insertions, 8 deletions

diff --git a/arch/arm/include/asm/arch-meson/gxbb.h b/arch/arm/include/asm/arch-meson/gxbb.h
index 95a6fe6998e..ef63dea4496 100644
--- a/arch/arm/include/asm/arch-meson/gxbb.h
+++ b/arch/arm/include/asm/arch-meson/gxbb.h
@@ -7,10 +7,27 @@
 #ifndef __GXBB_H__
 #define __GXBB_H__
 
+#define GXBB_FIRMWARE_MEM_SIZE	0x1000000
+
+#define GXBB_AOBUS_BASE		0xc8100000
 #define GXBB_PERIPHS_BASE	0xc8834400
 #define GXBB_HIU_BASE		0xc883c000
 #define GXBB_ETH_BASE		0xc9410000
 
+/* Always-On Peripherals registers */
+#define GXBB_AO_ADDR(off)	(GXBB_AOBUS_BASE + ((off) << 2))
+
+#define GXBB_AO_SEC_GP_CFG0	GXBB_AO_ADDR(0x90)
+#define GXBB_AO_SEC_GP_CFG3	GXBB_AO_ADDR(0x93)
+#define GXBB_AO_SEC_GP_CFG4	GXBB_AO_ADDR(0x94)
+#define GXBB_AO_SEC_GP_CFG5	GXBB_AO_ADDR(0x95)
+
+#define GXBB_AO_MEM_SIZE_MASK	0xFFFF0000
+#define GXBB_AO_MEM_SIZE_SHIFT	16
+#define GXBB_AO_BL31_RSVMEM_SIZE_MASK	0xFFFF0000
+#define GXBB_AO_BL31_RSVMEM_SIZE_SHIFT	16
+#define GXBB_AO_BL32_RSVMEM_SIZE_MASK	0xFFFF
+
 /* Peripherals registers */
 #define GXBB_PERIPHS_ADDR(off)	(GXBB_PERIPHS_BASE + ((off) << 2))
 
diff --git a/arch/arm/include/asm/arch-meson/mem.h b/arch/arm/include/asm/arch-meson/mem.h
new file mode 100644
index 00000000000..86a84170347
--- /dev/null
+++ b/arch/arm/include/asm/arch-meson/mem.h
@@ -0,0 +1,16 @@
+/*
+ * Copyright (C) 2016 BayLibre, SAS
+ * Author: Neil Armstrong <narmstrong@baylibre.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#ifndef __MESON_MEM_H__
+#define __MESON_MEM_H__
+
+/* Configure the reserved memory zones exported by the secure registers
+ * into EFI and DTB reserved memory entries.
+ */
+void meson_gx_init_reserved_memory(void *fdt);
+
+#endif /* __MESON_MEM_H__ */
diff --git a/arch/arm/mach-meson/board.c b/arch/arm/mach-meson/board.c
index e89c6aace98..908a0cae560 100644
--- a/arch/arm/mach-meson/board.c
+++ b/arch/arm/mach-meson/board.c
@@ -11,6 +11,9 @@
 #include <asm/arch/sm.h>
 #include <asm/armv8/mmu.h>
 #include <asm/unaligned.h>
+#include <linux/sizes.h>
+#include <efi_loader.h>
+#include <asm/io.h>
 
 DECLARE_GLOBAL_DATA_PTR;
 
@@ -34,15 +37,70 @@ int dram_init(void)
 	return 0;
 }
 
-int dram_init_banksize(void)
+phys_size_t get_effective_memsize(void)
 {
-	/* Reserve first 16 MiB of RAM for firmware */
-	gd->bd->bi_dram[0].start = 0x1000000;
-	gd->bd->bi_dram[0].size  = 0xf000000;
-	/* Reserve 2 MiB for ARM Trusted Firmware (BL31) */
-	gd->bd->bi_dram[1].start = 0x10000000;
-	gd->bd->bi_dram[1].size  = gd->ram_size - 0x10200000;
-	return 0;
+	/* Size is reported in MiB, convert it in bytes */
+	return ((readl(GXBB_AO_SEC_GP_CFG0) & GXBB_AO_MEM_SIZE_MASK)
+			>> GXBB_AO_MEM_SIZE_SHIFT) * SZ_1M;
+}
+
+static void meson_board_add_reserved_memory(void *fdt, u64 start, u64 size)
+{
+	int ret;
+
+	ret = fdt_add_mem_rsv(fdt, start, size);
+	if (ret)
+		printf("Could not reserve zone @ 0x%llx\n", start);
+
+	if (IS_ENABLED(CONFIG_EFI_LOADER)) {
+		efi_add_memory_map(start,
+				   ALIGN(size, EFI_PAGE_SIZE) >> EFI_PAGE_SHIFT,
+				   EFI_RESERVED_MEMORY_TYPE, false);
+	}
+}
+
+void meson_gx_init_reserved_memory(void *fdt)
+{
+	u64 bl31_size, bl31_start;
+	u64 bl32_size, bl32_start;
+	u32 reg;
+
+	/*
+	 * Get ARM Trusted Firmware reserved memory zones in :
+	 * - AO_SEC_GP_CFG3: bl32 & bl31 size in KiB, can be 0
+	 * - AO_SEC_GP_CFG5: bl31 physical start address, can be NULL
+	 * - AO_SEC_GP_CFG4: bl32 physical start address, can be NULL
+	 */
+
+	reg = readl(GXBB_AO_SEC_GP_CFG3);
+
+	bl31_size = ((reg & GXBB_AO_BL31_RSVMEM_SIZE_MASK)
+			>> GXBB_AO_BL31_RSVMEM_SIZE_SHIFT) * SZ_1K;
+	bl32_size = (reg & GXBB_AO_BL32_RSVMEM_SIZE_MASK) * SZ_1K;
+
+	bl31_start = readl(GXBB_AO_SEC_GP_CFG5);
+	bl32_start = readl(GXBB_AO_SEC_GP_CFG4);
+
+	/*
+	 * Early Meson GXBB Firmware revisions did not provide the reserved
+	 * memory zones in the registers, keep fixed memory zone handling.
+	 */
+	if (IS_ENABLED(CONFIG_MESON_GXBB) &&
+	    !reg && !bl31_start && !bl32_start) {
+		bl31_start = 0x10000000;
+		bl31_size = 0x200000;
+	}
+
+	/* Add first 16MiB reserved zone */
+	meson_board_add_reserved_memory(fdt, 0, GXBB_FIRMWARE_MEM_SIZE);
+
+	/* Add BL31 reserved zone */
+	if (bl31_start && bl31_size)
+		meson_board_add_reserved_memory(fdt, bl31_start, bl31_size);
+
+	/* Add BL32 reserved zone */
+	if (bl32_start && bl32_size)
+		meson_board_add_reserved_memory(fdt, bl32_start, bl32_size);
 }
 
 void reset_cpu(ulong addr)