[PATCH v2 1/1] arm: apple: Switch to fully dynamic mem layout

[Janne Grunau]

Support for Apple M1 Pro and Max will allow using a single binary for
all M1 SoCs. The M1 Pro/Max have a different memory layout. The RAM
start address is 0x100_0000_0000 instead of 0x8_0000_0000.
Replace the hardcoded memory layout with dynamic initialized
environment variables in board_late_init().

Tested on Mac Mini (2020) and Macbook Pro 14-inch (2021).

Signed-off-by: Janne Grunau <j at jannau.net>
Reviewed-by: Mark Kettenis <kettenis at openbsd.org>
---

Changed in v2:
 - ensure adresses are aligned
 - added space between addresses at the top and stack
 - added loadaddr and set the default to 0
 - pick up Mark's Reviewed-by
 - whitespace fixes

 arch/arm/mach-apple/board.c | 31 +++++++++++++++++++++++++++++++
 configs/apple_m1_defconfig  |  3 ++-
 include/configs/apple.h     |  5 -----
 3 files changed, 33 insertions(+), 6 deletions(-)

diff --git a/arch/arm/mach-apple/board.c b/arch/arm/mach-apple/board.c
index b7e8d212f1..46877569af 100644
--- a/arch/arm/mach-apple/board.c
+++ b/arch/arm/mach-apple/board.c
@@ -136,3 +136,34 @@ ulong board_get_usable_ram_top(ulong total_size)
 	 */
 	return 0x980000000;
 }
+
+int board_late_init(void)
+{
+	unsigned long base;
+	unsigned long top;
+	u32 status = 0;
+
+	/* Reserve 4M each for scriptaddr and pxefile_addr_r at the top of RAM
+	 * at least 1M below the stack.
+	 */
+	top = gd->start_addr_sp - CONFIG_STACK_SIZE - SZ_8M - SZ_1M;
+	top = ALIGN_DOWN(top, SZ_8M);
+
+	status |= env_set_hex("scriptaddr", top + SZ_4M);
+	status |= env_set_hex("pxefile_addr_r", top);
+
+	/* somewhat based on the Linux Kernel boot requirements:
+	 * align by 2M and maximal FDT size 2M
+	 */
+	base = ALIGN(gd->ram_base, SZ_2M);
+
+	status |= env_set_hex("fdt_addr_r", base);
+	status |= env_set_hex("kernel_addr_r", base + SZ_2M);
+	status |= env_set_hex("ramdisk_addr_r", base + SZ_128M);
+	status |= env_set_hex("loadaddr", base + SZ_2G);
+
+	if (status)
+		log_warning("late_init: Failed to set run time variables\n");
+
+	return 0;
+}
diff --git a/configs/apple_m1_defconfig b/configs/apple_m1_defconfig
index cb235e4e7d..b96d31db2c 100644
--- a/configs/apple_m1_defconfig
+++ b/configs/apple_m1_defconfig
@@ -4,10 +4,11 @@ CONFIG_DEFAULT_DEVICE_TREE="t8103-j274"
 CONFIG_DEBUG_UART_BASE=0x235200000
 CONFIG_DEBUG_UART_CLOCK=240000
 CONFIG_DEBUG_UART=y
-CONFIG_SYS_LOAD_ADDR=0x880000000
+CONFIG_SYS_LOAD_ADDR=0x0
 CONFIG_USE_PREBOOT=y
 # CONFIG_DISPLAY_CPUINFO is not set
 CONFIG_DISPLAY_BOARDINFO_LATE=y
+CONFIG_BOARD_LATE_INIT=y
 # CONFIG_NET is not set
 # CONFIG_MMC is not set
 CONFIG_DEBUG_UART_ANNOUNCE=y
diff --git a/include/configs/apple.h b/include/configs/apple.h
index 3e5fb495f1..f73f4f047b 100644
--- a/include/configs/apple.h
+++ b/include/configs/apple.h
@@ -9,10 +9,6 @@
 	"stdout=serial,vidconsole\0" \
 	"stderr=serial,vidconsole\0"
 
-#define ENV_MEM_LAYOUT_SETTINGS \
-	"fdt_addr_r=0x960100000\0" \
-	"kernel_addr_r=0x960200000\0"
-
 #if CONFIG_IS_ENABLED(CMD_USB)
 	#define BOOT_TARGET_USB(func) func(USB, usb, 0)
 #else
@@ -26,7 +22,6 @@
 
 #define CONFIG_EXTRA_ENV_SETTINGS \
 	ENV_DEVICE_SETTINGS \
-	ENV_MEM_LAYOUT_SETTINGS \
 	BOOTENV
 
 #endif
-- 
2.35.1