ARM: add basic support for the Broadcom BCM2835 SoC

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

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

Initial support is enough to boot to a serial console, execute a minimal
set of U-Boot commands, download data over a serial port, and boot a
Linux kernel. No storage or network drivers are implemented.

GPIO driver originally by Vikram Narayanan <vikram186@gmail.com>
with many fixes from myself.

Signed-off-by: Stephen Warren <swarren@wwwdotorg.org>

1 files changed, 55 insertions, 0 deletions

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);
+}