sunxi: add sun7i clocks and timer support.

This patch adds the basic clocks and timer support for the Allwinner A20
(sun7i) processor. This code will not been compiled until the build is hooked
up in a later patch. It has been split out to keep the patches manageable.

Some of the code here is common to multiple sunxi subarchtectures, hence files
are named sun4i which is the earliest similar variant.

Signed-off-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Emilio López <emilio@elopez.com.ar>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Henrik Nordstrom <henrik@henriknordstrom.net>
Signed-off-by: Jens Kuske <jenskuske@gmail.com>
Signed-off-by: Luke Leighton <lkcl@lkcl.net>
Signed-off-by: Oliver Schinagl <oliver@schinagl.nl>
Signed-off-by: Ian Campbell <ijc@hellion.org.uk>
Cc: Stefan Roese <sr@denx.de>
Cc: Tom Cubie <Mr.hipboi@gmail.com>
Reviewed-by: Tom Rini <trini@ti.com>

1 files changed, 113 insertions, 0 deletions

diff --git a/arch/arm/cpu/armv7/sunxi/timer.c b/arch/arm/cpu/armv7/sunxi/timer.c
new file mode 100644
index 0000000000..36263896d8
--- /dev/null
+++ b/arch/arm/cpu/armv7/sunxi/timer.c
@@ -0,0 +1,113 @@
+/*
+ * (C) Copyright 2007-2011
+ * Allwinner Technology Co., Ltd. <www.allwinnertech.com>
+ * Tom Cubie <tangliang@allwinnertech.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <asm/io.h>
+#include <asm/arch/timer.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+#define TIMER_MODE   (0x0 << 7)	/* continuous mode */
+#define TIMER_DIV    (0x0 << 4)	/* pre scale 1 */
+#define TIMER_SRC    (0x1 << 2)	/* osc24m */
+#define TIMER_RELOAD (0x1 << 1)	/* reload internal value */
+#define TIMER_EN     (0x1 << 0)	/* enable timer */
+
+#define TIMER_CLOCK		(24 * 1000 * 1000)
+#define COUNT_TO_USEC(x)	((x) / 24)
+#define USEC_TO_COUNT(x)	((x) * 24)
+#define TICKS_PER_HZ		(TIMER_CLOCK / CONFIG_SYS_HZ)
+#define TICKS_TO_HZ(x)		((x) / TICKS_PER_HZ)
+
+#define TIMER_LOAD_VAL		0xffffffff
+
+#define TIMER_NUM		0	/* we use timer 0 */
+
+/* read the 32-bit timer */
+static ulong read_timer(void)
+{
+	struct sunxi_timer_reg *timers =
+		(struct sunxi_timer_reg *)SUNXI_TIMER_BASE;
+	struct sunxi_timer *timer = &timers->timer[TIMER_NUM];
+
+	/*
+	 * The hardware timer counts down, therefore we invert to
+	 * produce an incrementing timer.
+	 */
+	return ~readl(&timer->val);
+}
+
+/* init timer register */
+int timer_init(void)
+{
+	struct sunxi_timer_reg *timers =
+		(struct sunxi_timer_reg *)SUNXI_TIMER_BASE;
+	struct sunxi_timer *timer = &timers->timer[TIMER_NUM];
+	writel(TIMER_LOAD_VAL, &timer->inter);
+	writel(TIMER_MODE | TIMER_DIV | TIMER_SRC | TIMER_RELOAD | TIMER_EN,
+	       &timer->ctl);
+
+	return 0;
+}
+
+/* timer without interrupts */
+ulong get_timer(ulong base)
+{
+	return get_timer_masked() - base;
+}
+
+ulong get_timer_masked(void)
+{
+	/* current tick value */
+	ulong now = TICKS_TO_HZ(read_timer());
+
+	if (now >= gd->arch.lastinc)	/* normal (non rollover) */
+		gd->arch.tbl += (now - gd->arch.lastinc);
+	else {
+		/* rollover */
+		gd->arch.tbl += (TICKS_TO_HZ(TIMER_LOAD_VAL)
+				- gd->arch.lastinc) + now;
+	}
+	gd->arch.lastinc = now;
+
+	return gd->arch.tbl;
+}
+
+/* delay x useconds */
+void __udelay(unsigned long usec)
+{
+	long tmo = USEC_TO_COUNT(usec);
+	ulong now, last = read_timer();
+
+	while (tmo > 0) {
+		now = read_timer();
+		if (now > last)	/* normal (non rollover) */
+			tmo -= now - last;
+		else		/* rollover */
+			tmo -= TIMER_LOAD_VAL - last + now;
+		last = now;
+	}
+}
+
+/*
+ * This function is derived from PowerPC code (read timebase as long long).
+ * On ARM it just returns the timer value.
+ */
+unsigned long long get_ticks(void)
+{
+	return get_timer(0);
+}
+
+/*
+ * This function is derived from PowerPC code (timebase clock frequency).
+ * On ARM it returns the number of timer ticks per second.
+ */
+ulong get_tbclk(void)
+{
+	return CONFIG_SYS_HZ;
+}