ARM: add Raspberry Pi 3 64-bit config

On all Pis so far, the VC FW provides a short stub to set up the ARM CPU
before entering the kernel (a/k/a U-Boot for us). This feature is not
currently supported by the VC FW when booting in 64-bit mode. However,
this feature will likely appear in the near future, and this U-Boot port
assumes that such a feature is in place. Without that feature, or a
temporary workaround described below, U-Boot will not boot.

Once the VC FW does provide the ARM stub, u-boot.bin built for rpi_3 can
be used drectly as kernel7.img, in the same way as any other RPi port. The
following config.txt is required:

    # Fix mini UART input frequency, and setup/enable up the UART.
    # Without this option, U-Boot will not boot, even if you don't care
    # about the serial console. This option will always be required for
    # all RPi3 use-cases, unless the PL011 UART is used, which is not
    # yet supported by rpi_3* builds of U-Boot.
    enable_uart=1
    # Boot in AArch64 (64-bit) mode.
    # It is possible that a future VC FW will remove the need for this
    # option, instead auto-setting 32-/64-bit mode based on the "kernel"
    # filename present on the SD card.
    arm_control=0x200

Prior to the VC FW providing the ARM boot stub, you can use the following
steps to build an equivalent stub into the U-Boot binary:

git clone https://github.com/swarren/rpi-3-aarch64-demo.git \
    ../rpi-3-aarch64-demo
(cd ../rpi-3-aarch64-demo && ./build.sh)
Build U-Boot for rpi_3 in the usual way
cat ../rpi-3-aarch64-demo/armstub64.bin u-boot.bin > u-boot.bin.stubbed
Use u-boot.bin.stubbed as kernel7.img on the Pi SD card.

In this case, the following additional entries are required in config.txt:

    # Tell the FW to load the kernel image at address 0, the reset vector.
    kernel_old=1

Signed-off-by: Stephen Warren <swarren@wwwdotorg.org>
Reviewed-by: Tom Rini <trini@konsulko.com>

arch/arm/mach-bcm283x/Kconfig

@@ -70,12 +70,18 @@ config TARGET_RPI_3_32B
 	select BCM2837
 	select CPU_V7
 
+config TARGET_RPI_3
+	bool "Raspberry Pi 3 64-bit build"
+	select ARM64
+	select BCM2837
+
 endchoice
 
 config SYS_BOARD
 	default "rpi" if TARGET_RPI
 	default "rpi_2" if TARGET_RPI_2
 	default "rpi_3_32b" if TARGET_RPI_3_32B
+	default "rpi_3" if TARGET_RPI_3
 
 config SYS_VENDOR
 	default "raspberrypi"
@@ -87,5 +93,6 @@ config SYS_CONFIG_NAME
 	default "rpi" if TARGET_RPI
 	default "rpi_2" if TARGET_RPI_2
 	default "rpi_3_32b" if TARGET_RPI_3_32B
+	default "rpi_3" if TARGET_RPI_3
 
 endmenu

board/raspberrypi/rpi/rpi.c

@@ -19,6 +19,9 @@
 #include <asm/global_data.h>
 #include <dm/platform_data/serial_pl01x.h>
 #include <dm/platform_data/serial_bcm283x_mu.h>
+#ifdef CONFIG_ARM64
+#include <asm/armv8/mmu.h>
+#endif
 
 DECLARE_GLOBAL_DATA_PTR;
 
@@ -228,6 +231,28 @@ static uint32_t rev_scheme;
 static uint32_t rev_type;
 static const struct rpi_model *model;
 
+#ifdef CONFIG_ARM64
+static struct mm_region bcm2837_mem_map[] = {
+	{
+		.base = 0x00000000UL,
+		.size = 0x3f000000UL,
+		.attrs = PTE_BLOCK_MEMTYPE(MT_NORMAL) |
+			 PTE_BLOCK_INNER_SHARE
+	}, {
+		.base = 0x3f000000UL,
+		.size = 0x01000000UL,
+		.attrs = PTE_BLOCK_MEMTYPE(MT_DEVICE_NGNRNE) |
+			 PTE_BLOCK_NON_SHARE |
+			 PTE_BLOCK_PXN | PTE_BLOCK_UXN
+	}, {
+		/* List terminator */
+		0,
+	}
+};
+
+struct mm_region *mem_map = bcm2837_mem_map;
+#endif
+
 int dram_init(void)
 {
 	ALLOC_CACHE_ALIGN_BUFFER(struct msg_get_arm_mem, msg, 1);

board/raspberrypi/rpi_3/MAINTAINERS

@@ -0,0 +1,6 @@
+RPI_3_BOARD
+M:	Stephen Warren <swarren@wwwdotorg.org>
+S:	Maintained
+F:	board/raspberrypi/rpi_3/
+F:	include/configs/rpi_3.h
+F:	configs/rpi_3_defconfig

board/raspberrypi/rpi_3/Makefile

@@ -0,0 +1,7 @@
+#
+# (C) Copyright 2012-2016 Stephen Warren <swarren@wwwdotorg.org>
+#
+# SPDX-License-Identifier:	GPL-2.0
+#
+
+obj-y	:= ../rpi/rpi.o

configs/rpi_3_defconfig

@@ -0,0 +1,11 @@
+CONFIG_ARM=y
+CONFIG_ARCH_BCM283X=y
+CONFIG_TARGET_RPI_3=y
+CONFIG_OF_BOARD_SETUP=y
+CONFIG_SYS_PROMPT="U-Boot> "
+# CONFIG_CMD_IMLS is not set
+# CONFIG_CMD_FLASH is not set
+# CONFIG_CMD_FPGA is not set
+CONFIG_CMD_GPIO=y
+CONFIG_PHYS_TO_BUS=y
+CONFIG_OF_LIBFDT=y

include/configs/rpi-common.h

@@ -13,9 +13,12 @@
 /* Architecture, CPU, etc.*/
 #define CONFIG_ARCH_CPU_INIT
 
+/* Use SoC timer for AArch32, but architected timer for AArch64 */
+#ifndef CONFIG_ARM64
 #define CONFIG_SYS_TIMER_RATE		1000000
 #define CONFIG_SYS_TIMER_COUNTER	\
 	(&((struct bcm2835_timer_regs *)BCM2835_TIMER_PHYSADDR)->clo)
+#endif
 
 /*
  * 2835 is a SKU in a series for which the 2708 is the first or primary SoC,

include/configs/rpi_3.h

@@ -0,0 +1,14 @@
+/*
+ * (C) Copyright 2012-2016 Stephen Warren <swarren@wwwdotorg.org>
+ *
+ * SPDX-License-Identifier:	GPL-2.0
+ */
+
+#ifndef __CONFIG_H
+#define __CONFIG_H
+
+#define CONFIG_SYS_CACHELINE_SIZE		64
+
+#include "rpi-common.h"
+
+#endif