[PATCH 1/2] ARM: add basic support for the Broadcom BCM2835 SoC

Stephen Warren swarren at wwwdotorg.org
Thu Jun 7 01:45:24 EDT 2012 

This SoC is used in the Raspberry Pi, for example.

Initial support is enough to boot to a serial console, and execute a
minimal set of U-Boot commands. No drivers are implemented. For more
details, see http://www.broadcom.com/products/BCM2835 or
http://www.raspberrypi.org/wp-content/uploads/2012/02/BCM2835-ARM-Peripherals.pdf.

Signed-off-by: Stephen Warren <swarren at wwwdotorg.org>
---
 arch/arm/cpu/arm1176/bcm2835/Makefile        |   37 +++++++++++++++++
 arch/arm/cpu/arm1176/bcm2835/config.mk       |   19 +++++++++
 arch/arm/cpu/arm1176/bcm2835/lowlevel_init.S |   19 +++++++++
 arch/arm/cpu/arm1176/bcm2835/reset.c         |   27 +++++++++++++
 arch/arm/cpu/arm1176/bcm2835/timer.c         |   55 ++++++++++++++++++++++++++
 arch/arm/include/asm/arch-bcm2835/timer.h    |   37 +++++++++++++++++
 6 files changed, 194 insertions(+)
 create mode 100644 arch/arm/cpu/arm1176/bcm2835/Makefile
 create mode 100644 arch/arm/cpu/arm1176/bcm2835/config.mk
 create mode 100644 arch/arm/cpu/arm1176/bcm2835/lowlevel_init.S
 create mode 100644 arch/arm/cpu/arm1176/bcm2835/reset.c
 create mode 100644 arch/arm/cpu/arm1176/bcm2835/timer.c
 create mode 100644 arch/arm/include/asm/arch-bcm2835/timer.h

diff --git a/arch/arm/cpu/arm1176/bcm2835/Makefile b/arch/arm/cpu/arm1176/bcm2835/Makefile
new file mode 100644
index 0000000..4ea6d6b
--- /dev/null
+++ b/arch/arm/cpu/arm1176/bcm2835/Makefile
@@ -0,0 +1,37 @@
+#
+# See file CREDITS for list of people who contributed to this
+# project.
+#
+# 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.
+#
+# 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 $(TOPDIR)/config.mk
+
+LIB	= $(obj)lib$(SOC).o
+
+SOBJS	:= lowlevel_init.o
+COBJS	:= reset.o timer.o
+
+SRCS	:= $(SOBJS:.o=.c) $(COBJS:.o=.c)
+OBJS	:= $(addprefix $(obj),$(SOBJS) $(COBJS))
+
+all:	$(obj).depend $(LIB)
+
+$(LIB):	$(OBJS)
+	$(call cmd_link_o_target, $(OBJS))
+
+#########################################################################
+
+# defines $(obj).depend target
+include $(SRCTREE)/rules.mk
+
+sinclude $(obj).depend
+
+#########################################################################
diff --git a/arch/arm/cpu/arm1176/bcm2835/config.mk b/arch/arm/cpu/arm1176/bcm2835/config.mk
new file mode 100644
index 0000000..b87ce24
--- /dev/null
+++ b/arch/arm/cpu/arm1176/bcm2835/config.mk
@@ -0,0 +1,19 @@
+#
+# (C) Copyright 2012 Stephen Warren
+#
+# See file CREDITS for list of people who contributed to this
+# project.
+#
+# 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.
+#
+# 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.
+
+# Don't attempt to override the target CPU/ABI options;
+# the Raspberry Pi toolchain does the right thing by default.
+PLATFORM_RELFLAGS := $(filter-out -msoft-float,$(PLATFORM_RELFLAGS))
+PLATFORM_CPPFLAGS := $(filter-out -march=armv5t,$(PLATFORM_CPPFLAGS))
diff --git a/arch/arm/cpu/arm1176/bcm2835/lowlevel_init.S b/arch/arm/cpu/arm1176/bcm2835/lowlevel_init.S
new file mode 100644
index 0000000..c7b0843
--- /dev/null
+++ b/arch/arm/cpu/arm1176/bcm2835/lowlevel_init.S
@@ -0,0 +1,19 @@
+/*
+ * (C) Copyright 2012 Stephen Warren
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * 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.
+ *
+ * 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.
+ */
+
+.globl lowlevel_init
+lowlevel_init:
+	mov	pc, lr
diff --git a/arch/arm/cpu/arm1176/bcm2835/reset.c b/arch/arm/cpu/arm1176/bcm2835/reset.c
new file mode 100644
index 0000000..69c9577
--- /dev/null
+++ b/arch/arm/cpu/arm1176/bcm2835/reset.c
@@ -0,0 +1,27 @@
+/*
+ * (C) Copyright 2012 Stephen Warren
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * 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.
+ *
+ * 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 <common.h>
+#include <asm/io.h>
+
+void reset_cpu(ulong addr)
+{
+	/*
+	 * We should probably use the WDT module here, but an unaligned
+	 * access will do the trick for now.
+	 */
+	readl(1);
+}
diff --git a/arch/arm/cpu/arm1176/bcm2835/timer.c b/arch/arm/cpu/arm1176/bcm2835/timer.c
new file mode 100644
index 0000000..d232d7e
--- /dev/null
+++ b/arch/arm/cpu/arm1176/bcm2835/timer.c
@@ -0,0 +1,55 @@
+/*
+ * (C) Copyright 2012 Stephen Warren
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * 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.
+ *
+ * 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 <common.h>
+#include <asm/io.h>
+#include <asm/arch/timer.h>
+
+int timer_init(void)
+{
+	return 0;
+}
+
+ulong get_timer(ulong base)
+{
+	struct bcm2835_timer_regs *regs =
+		(struct bcm2835_timer_regs *)BCM2835_TIMER_PHYSADDR;
+
+	return readl(&regs->clo) - base;
+}
+
+unsigned long long get_ticks(void)
+{
+	return get_timer(0);
+}
+
+ulong get_tbclk(void)
+{
+	return CONFIG_SYS_HZ;
+}
+
+void __udelay(unsigned long usec)
+{
+	ulong endtime;
+	signed long diff;
+
+	endtime = get_timer(0) + usec;
+
+	do {
+		ulong now = get_timer(0);
+		diff = endtime - now;
+	} while (diff >= 0);
+}
diff --git a/arch/arm/include/asm/arch-bcm2835/timer.h b/arch/arm/include/asm/arch-bcm2835/timer.h
new file mode 100644
index 0000000..30c70e0
--- /dev/null
+++ b/arch/arm/include/asm/arch-bcm2835/timer.h
@@ -0,0 +1,37 @@
+/*
+ * (C) Copyright 2012 Stephen Warren
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * 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.
+ *
+ * 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 _BCM2835_TIMER_H
+#define _BCM2835_TIMER_H
+
+#define BCM2835_TIMER_PHYSADDR	0x20003000
+
+struct bcm2835_timer_regs {
+	u32 cs;
+	u32 clo;
+	u32 chi;
+	u32 c0;
+	u32 c1;
+	u32 c2;
+	u32 c3;
+};
+
+#define BCM2835_TIMER_CS_M3	(1 << 3)
+#define BCM2835_TIMER_CS_M2	(1 << 2)
+#define BCM2835_TIMER_CS_M1	(1 << 1)
+#define BCM2835_TIMER_CS_M0	(1 << 0)
+
+#endif
-- 
1.7.9.5

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