ARM: add infra-structure for BCM2835 and Raspberry Pi

The BCM2835 is an ARM SoC from Broadcom. This patch adds very basic
support for this SoC.

http://www.broadcom.com/products/BCM2835
http://www.raspberrypi.org/wp-content/uploads/2012/02/BCM2835-ARM-Peripherals.pdf

Note that the documentation in the latter .pdf assumes the MMU setup
that's used on the "VideoCore" companion processor, and does not document
physical peripheral addresses. Subtract 0x5e000000 to obtain the physical
addresses. This is accounted for by the ranges property in the /soc node
in the device tree.

The BCM2835 SoC is used in the Raspberry Pi. This patch also adds a
minimal device tree for this board; enough to see some very early kernel
boot messages through earlyprintk. However, this patch does not yet
provide a useful booting system.

http://www.raspberrypi.org/.

This patch was extracted from git://github.com/lp0/linux.git branch
rpi-split from 3-4 months ago, and significantly stripped down and
modified since.

Signed-off-by: Chris Boot <[e-mail]>
Signed-off-by: Simon Arlott <[e-mail]>
Signed-off-by: Dom Cobley <[e-mail]>
Signed-off-by: Dom Cobley <[e-mail]>
Signed-off-by: Stephen Warren <[e-mail]>
Acked-by: Arnd Bergmann <[e-mail]>

Documentation/devicetree/bindings/arm/bcm2835.txt

···
+Broadcom BCM2835 device tree bindings
+-------------------------------------------
+
+Boards with the BCM2835 SoC shall have the following properties:
+
+Required root node property:
+
+compatible = "brcm,bcm2835";

Documentation/devicetree/bindings/vendor-prefixes.txt

···
 arm	ARM Ltd.
 atmel	Atmel Corporation
 bosch	Bosch Sensortec GmbH
+brcm	Broadcom Corporation
 cavium	Cavium, Inc.
 chrp	Common Hardware Reference Platform
 cortina	Cortina Systems, Inc.

arch/arm/Kconfig

···
 	  This enables support for systems based on Atmel
 	  AT91RM9200 and AT91SAM9* processors.
 
+config ARCH_BCM2835
+	bool "Broadcom BCM2835 family"
+	select ARCH_WANT_OPTIONAL_GPIOLIB
+	select ARM_AMBA
+	select ARM_ERRATA_411920
+	select ARM_TIMER_SP804
+	select CLKDEV_LOOKUP
+	select COMMON_CLK
+	select CPU_V6
+	select GENERIC_CLOCKEVENTS
+	select MULTI_IRQ_HANDLER
+	select SPARSE_IRQ
+	select USE_OF
+	help
+	  This enables support for the Broadcom BCM2835 SoC. This SoC is
+	  use in the Raspberry Pi, and Roku 2 devices.
+
 config ARCH_BCMRING
 	bool "Broadcom BCMRING"
 	depends on MMU

arch/arm/Makefile

···
 # Machine directory name.  This list is sorted alphanumerically
 # by CONFIG_* macro name.
 machine-$(CONFIG_ARCH_AT91)		:= at91
+machine-$(CONFIG_ARCH_BCM2835)		:= bcm2835
 machine-$(CONFIG_ARCH_BCMRING)		:= bcmring
 machine-$(CONFIG_ARCH_CLPS711X)		:= clps711x
 machine-$(CONFIG_ARCH_CNS3XXX)		:= cns3xxx

arch/arm/boot/dts/bcm2835-rpi-b.dts

···
+/dts-v1/;
+/memreserve/ 0x0c000000 0x04000000;
+/include/ "bcm2835.dtsi"
+
+/ {
+	compatible = "raspberrypi,model-b", "brcm,bcm2835";
+	model = "Raspberry Pi Model B";
+
+	memory {
+		reg = <0 0x10000000>;
+	};
+};

arch/arm/boot/dts/bcm2835.dtsi

···
+/include/ "skeleton.dtsi"
+
+/ {
+	compatible = "brcm,bcm2835";
+	model = "BCM2835";
+
+	chosen {
+		bootargs = "earlyprintk";
+	};
+
+	soc {
+		compatible = "simple-bus";
+		#address-cells = <1>;
+		#size-cells = <1>;
+		ranges = <0x7e000000 0x20000000 0x02000000>;
+	};
+};

arch/arm/configs/bcm2835_defconfig

···
+CONFIG_EXPERIMENTAL=y
+# CONFIG_LOCALVERSION_AUTO is not set
+CONFIG_SYSVIPC=y
+CONFIG_BSD_PROCESS_ACCT=y
+CONFIG_BSD_PROCESS_ACCT_V3=y
+CONFIG_FHANDLE=y
+CONFIG_NO_HZ=y
+CONFIG_HIGH_RES_TIMERS=y
+CONFIG_LOG_BUF_SHIFT=18
+CONFIG_CGROUP_FREEZER=y
+CONFIG_CGROUP_DEVICE=y
+CONFIG_CPUSETS=y
+CONFIG_CGROUP_CPUACCT=y
+CONFIG_RESOURCE_COUNTERS=y
+CONFIG_CGROUP_PERF=y
+CONFIG_CFS_BANDWIDTH=y
+CONFIG_RT_GROUP_SCHED=y
+CONFIG_NAMESPACES=y
+CONFIG_SCHED_AUTOGROUP=y
+CONFIG_RELAY=y
+CONFIG_BLK_DEV_INITRD=y
+CONFIG_RD_BZIP2=y
+CONFIG_RD_LZMA=y
+CONFIG_RD_XZ=y
+CONFIG_RD_LZO=y
+CONFIG_CC_OPTIMIZE_FOR_SIZE=y
+CONFIG_KALLSYMS_ALL=y
+CONFIG_EMBEDDED=y
+# CONFIG_COMPAT_BRK is not set
+CONFIG_PROFILING=y
+CONFIG_OPROFILE=y
+CONFIG_JUMP_LABEL=y
+# CONFIG_BLOCK is not set
+CONFIG_ARCH_BCM2835=y
+CONFIG_PREEMPT_VOLUNTARY=y
+CONFIG_AEABI=y
+CONFIG_COMPACTION=y
+CONFIG_KSM=y
+CONFIG_DEFAULT_MMAP_MIN_ADDR=65536
+CONFIG_CLEANCACHE=y
+CONFIG_SECCOMP=y
+CONFIG_CC_STACKPROTECTOR=y
+CONFIG_KEXEC=y
+CONFIG_CRASH_DUMP=y
+CONFIG_VFP=y
+# CONFIG_CORE_DUMP_DEFAULT_ELF_HEADERS is not set
+# CONFIG_SUSPEND is not set
+CONFIG_DEVTMPFS=y
+CONFIG_DEVTMPFS_MOUNT=y
+# CONFIG_STANDALONE is not set
+# CONFIG_INPUT_MOUSEDEV is not set
+# CONFIG_INPUT_KEYBOARD is not set
+# CONFIG_INPUT_MOUSE is not set
+# CONFIG_SERIO is not set
+# CONFIG_VT is not set
+# CONFIG_UNIX98_PTYS is not set
+# CONFIG_LEGACY_PTYS is not set
+# CONFIG_DEVKMEM is not set
+CONFIG_SERIAL_AMBA_PL011=y
+CONFIG_SERIAL_AMBA_PL011_CONSOLE=y
+CONFIG_TTY_PRINTK=y
+# CONFIG_HW_RANDOM is not set
+# CONFIG_HWMON is not set
+# CONFIG_USB_SUPPORT is not set
+# CONFIG_IOMMU_SUPPORT is not set
+# CONFIG_FILE_LOCKING is not set
+# CONFIG_DNOTIFY is not set
+# CONFIG_INOTIFY_USER is not set
+# CONFIG_PROC_FS is not set
+# CONFIG_SYSFS is not set
+# CONFIG_MISC_FILESYSTEMS is not set
+CONFIG_PRINTK_TIME=y
+# CONFIG_ENABLE_WARN_DEPRECATED is not set
+# CONFIG_ENABLE_MUST_CHECK is not set
+CONFIG_UNUSED_SYMBOLS=y
+CONFIG_LOCKUP_DETECTOR=y
+CONFIG_DEBUG_INFO=y
+CONFIG_DEBUG_MEMORY_INIT=y
+CONFIG_BOOT_PRINTK_DELAY=y
+CONFIG_SCHED_TRACER=y
+CONFIG_STACK_TRACER=y
+CONFIG_FUNCTION_PROFILER=y
+CONFIG_DYNAMIC_DEBUG=y
+CONFIG_KGDB=y
+CONFIG_KGDB_KDB=y
+CONFIG_TEST_KSTRTOX=y
+CONFIG_STRICT_DEVMEM=y
+CONFIG_DEBUG_LL=y
+CONFIG_EARLY_PRINTK=y
+# CONFIG_XZ_DEC_X86 is not set
+# CONFIG_XZ_DEC_POWERPC is not set
+# CONFIG_XZ_DEC_IA64 is not set
+# CONFIG_XZ_DEC_ARM is not set
+# CONFIG_XZ_DEC_ARMTHUMB is not set
+# CONFIG_XZ_DEC_SPARC is not set

arch/arm/mach-bcm2835/Makefile

···
+obj-y += bcm2835.o

arch/arm/mach-bcm2835/Makefile.boot

···
+   zreladdr-y := 0x00008000
+params_phys-y := 0x00000100
+initrd_phys-y := 0x00800000
+
+dtb-y += bcm2835-rpi-b.dtb

arch/arm/mach-bcm2835/bcm2835.c

···
+/*
+ * Copyright (C) 2010 Broadcom
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/init.h>
+#include <linux/of_platform.h>
+
+#include <asm/mach/arch.h>
+#include <asm/mach/map.h>
+#include <asm/mach/time.h>
+#include <asm/exception.h>
+
+#include <mach/bcm2835_soc.h>
+
+static struct map_desc io_map __initdata = {
+	.virtual = BCM2835_PERIPH_VIRT,
+	.pfn = __phys_to_pfn(BCM2835_PERIPH_PHYS),
+	.length = BCM2835_PERIPH_SIZE,
+	.type = MT_DEVICE
+};
+
+void __init bcm2835_map_io(void)
+{
+	iotable_init(&io_map, 1);
+}
+
+void __init bcm2835_init_irq(void)
+{
+}
+
+asmlinkage void __exception_irq_entry bcm2835_handle_irq(struct pt_regs *regs)
+{
+}
+
+void __init bcm2835_init(void)
+{
+	int ret;
+
+	ret = of_platform_populate(NULL, of_default_bus_match_table, NULL,
+				   NULL);
+	if (ret) {
+		pr_err("of_platform_populate failed: %d\n", ret);
+		BUG();
+	}
+}
+
+static void __init bcm2835_timer_init(void)
+{
+}
+
+struct sys_timer bcm2835_timer = {
+	.init = bcm2835_timer_init
+};
+
+static const char * const bcm2835_compat[] = {
+	"brcm,bcm2835",
+	NULL
+};
+
+DT_MACHINE_START(BCM2835, "BCM2835")
+	.map_io = bcm2835_map_io,
+	.init_irq = bcm2835_init_irq,
+	.handle_irq = bcm2835_handle_irq,
+	.init_machine = bcm2835_init,
+	.timer = &bcm2835_timer,
+	.dt_compat = bcm2835_compat
+MACHINE_END

arch/arm/mach-bcm2835/include/mach/bcm2835_soc.h

···
+/*
+ * Copyright (C) 2012 Stephen Warren
+ *
+ * Derived from code:
+ * Copyright (C) 2010 Broadcom
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#ifndef __MACH_BCM2835_BCM2835_SOC_H__
+#define __MACH_BCM2835_BCM2835_SOC_H__
+
+#include <asm/sizes.h>
+
+#define BCM2835_PERIPH_PHYS	0x20000000
+#define BCM2835_PERIPH_VIRT	0xf0000000
+#define BCM2835_PERIPH_SIZE	SZ_16M
+#define BCM2835_DEBUG_PHYS	0x20201000
+#define BCM2835_DEBUG_VIRT	0xf0201000
+
+#endif

arch/arm/mach-bcm2835/include/mach/debug-macro.S

···
+/*
+ * Debugging macro include header
+ *
+ * Copyright (C) 2010 Broadcom
+ * Copyright (C) 1994-1999 Russell King
+ * Moved from linux/arch/arm/kernel/debug.S by Ben Dooks
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ */
+
+#include <mach/bcm2835_soc.h>
+
+	.macro	addruart, rp, rv, tmp
+	ldr	\rp, =BCM2835_DEBUG_PHYS
+	ldr	\rv, =BCM2835_DEBUG_VIRT
+	.endm
+
+#include <asm/hardware/debug-pl01x.S>

arch/arm/mach-bcm2835/include/mach/timex.h

···
+/*
+ *  BCM2835 system clock frequency
+ *
+ *  Copyright (C) 2010 Broadcom
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifndef __ASM_ARCH_TIMEX_H
+#define __ASM_ARCH_TIMEX_H
+
+#define CLOCK_TICK_RATE		(1000000)
+
+#endif

arch/arm/mach-bcm2835/include/mach/uncompress.h

···
+/*
+ * Copyright (C) 2010 Broadcom
+ * Copyright (C) 2003 ARM Limited
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/io.h>
+#include <linux/amba/serial.h>
+#include <mach/bcm2835_soc.h>
+
+#define UART0_BASE BCM2835_DEBUG_PHYS
+
+#define BCM2835_UART_DR IOMEM(UART0_BASE + UART01x_DR)
+#define BCM2835_UART_FR IOMEM(UART0_BASE + UART01x_FR)
+#define BCM2835_UART_CR IOMEM(UART0_BASE + UART011_CR)
+
+static inline void putc(int c)
+{
+	while (__raw_readl(BCM2835_UART_FR) & UART01x_FR_TXFF)
+		barrier();
+
+	__raw_writel(c, BCM2835_UART_DR);
+}
+
+static inline void flush(void)
+{
+	int fr;
+
+	do {
+		fr = __raw_readl(BCM2835_UART_FR);
+		barrier();
+	} while ((fr & (UART011_FR_TXFE | UART01x_FR_BUSY)) != UART011_FR_TXFE);
+}
+
+#define arch_decomp_setup()
+#define arch_decomp_wdog()