Adding upstream version 5.10.209.upstream/5.10.209upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 251 insertions, 0 deletions

diff --git a/arch/arm/mach-spear/time.c b/arch/arm/mach-spear/time.c
new file mode 100644
index 000000000..d1fdb6066
--- /dev/null
+++ b/arch/arm/mach-spear/time.c
@@ -0,0 +1,251 @@
+/*
+ * arch/arm/plat-spear/time.c
+ *
+ * Copyright (C) 2010 ST Microelectronics
+ * Shiraz Hashim<shiraz.linux.kernel@gmail.com>
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <linux/clk.h>
+#include <linux/clockchips.h>
+#include <linux/clocksource.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/ioport.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/of_irq.h>
+#include <linux/of_address.h>
+#include <linux/time.h>
+#include <linux/irq.h>
+#include <asm/mach/time.h>
+#include "generic.h"
+
+/*
+ * We would use TIMER0 and TIMER1 as clockevent and clocksource.
+ * Timer0 and Timer1 both belong to same gpt block in cpu subbsystem. Further
+ * they share same functional clock. Any change in one's functional clock will
+ * also affect other timer.
+ */
+
+#define CLKEVT	0	/* gpt0, channel0 as clockevent */
+#define CLKSRC	1	/* gpt0, channel1 as clocksource */
+
+/* Register offsets, x is channel number */
+#define CR(x)		((x) * 0x80 + 0x80)
+#define IR(x)		((x) * 0x80 + 0x84)
+#define LOAD(x)		((x) * 0x80 + 0x88)
+#define COUNT(x)	((x) * 0x80 + 0x8C)
+
+/* Reg bit definitions */
+#define CTRL_INT_ENABLE		0x0100
+#define CTRL_ENABLE		0x0020
+#define CTRL_ONE_SHOT		0x0010
+
+#define CTRL_PRESCALER1		0x0
+#define CTRL_PRESCALER2		0x1
+#define CTRL_PRESCALER4		0x2
+#define CTRL_PRESCALER8		0x3
+#define CTRL_PRESCALER16	0x4
+#define CTRL_PRESCALER32	0x5
+#define CTRL_PRESCALER64	0x6
+#define CTRL_PRESCALER128	0x7
+#define CTRL_PRESCALER256	0x8
+
+#define INT_STATUS		0x1
+
+/*
+ * Minimum clocksource/clockevent timer range in seconds
+ */
+#define SPEAR_MIN_RANGE 4
+
+static __iomem void *gpt_base;
+static struct clk *gpt_clk;
+
+static int clockevent_next_event(unsigned long evt,
+				 struct clock_event_device *clk_event_dev);
+
+static void __init spear_clocksource_init(void)
+{
+	u32 tick_rate;
+	u16 val;
+
+	/* program the prescaler (/256)*/
+	writew(CTRL_PRESCALER256, gpt_base + CR(CLKSRC));
+
+	/* find out actual clock driving Timer */
+	tick_rate = clk_get_rate(gpt_clk);
+	tick_rate >>= CTRL_PRESCALER256;
+
+	writew(0xFFFF, gpt_base + LOAD(CLKSRC));
+
+	val = readw(gpt_base + CR(CLKSRC));
+	val &= ~CTRL_ONE_SHOT;	/* autoreload mode */
+	val |= CTRL_ENABLE ;
+	writew(val, gpt_base + CR(CLKSRC));
+
+	/* register the clocksource */
+	clocksource_mmio_init(gpt_base + COUNT(CLKSRC), "tmr1", tick_rate,
+		200, 16, clocksource_mmio_readw_up);
+}
+
+static inline void timer_shutdown(struct clock_event_device *evt)
+{
+	u16 val = readw(gpt_base + CR(CLKEVT));
+
+	/* stop the timer */
+	val &= ~CTRL_ENABLE;
+	writew(val, gpt_base + CR(CLKEVT));
+}
+
+static int spear_shutdown(struct clock_event_device *evt)
+{
+	timer_shutdown(evt);
+
+	return 0;
+}
+
+static int spear_set_oneshot(struct clock_event_device *evt)
+{
+	u16 val;
+
+	/* stop the timer */
+	timer_shutdown(evt);
+
+	val = readw(gpt_base + CR(CLKEVT));
+	val |= CTRL_ONE_SHOT;
+	writew(val, gpt_base + CR(CLKEVT));
+
+	return 0;
+}
+
+static int spear_set_periodic(struct clock_event_device *evt)
+{
+	u32 period;
+	u16 val;
+
+	/* stop the timer */
+	timer_shutdown(evt);
+
+	period = clk_get_rate(gpt_clk) / HZ;
+	period >>= CTRL_PRESCALER16;
+	writew(period, gpt_base + LOAD(CLKEVT));
+
+	val = readw(gpt_base + CR(CLKEVT));
+	val &= ~CTRL_ONE_SHOT;
+	val |= CTRL_ENABLE | CTRL_INT_ENABLE;
+	writew(val, gpt_base + CR(CLKEVT));
+
+	return 0;
+}
+
+static struct clock_event_device clkevt = {
+	.name = "tmr0",
+	.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
+	.set_state_shutdown = spear_shutdown,
+	.set_state_periodic = spear_set_periodic,
+	.set_state_oneshot = spear_set_oneshot,
+	.tick_resume = spear_shutdown,
+	.set_next_event = clockevent_next_event,
+	.shift = 0,	/* to be computed */
+};
+
+static int clockevent_next_event(unsigned long cycles,
+				 struct clock_event_device *clk_event_dev)
+{
+	u16 val = readw(gpt_base + CR(CLKEVT));
+
+	if (val & CTRL_ENABLE)
+		writew(val & ~CTRL_ENABLE, gpt_base + CR(CLKEVT));
+
+	writew(cycles, gpt_base + LOAD(CLKEVT));
+
+	val |= CTRL_ENABLE | CTRL_INT_ENABLE;
+	writew(val, gpt_base + CR(CLKEVT));
+
+	return 0;
+}
+
+static irqreturn_t spear_timer_interrupt(int irq, void *dev_id)
+{
+	struct clock_event_device *evt = &clkevt;
+
+	writew(INT_STATUS, gpt_base + IR(CLKEVT));
+
+	evt->event_handler(evt);
+
+	return IRQ_HANDLED;
+}
+
+static void __init spear_clockevent_init(int irq)
+{
+	u32 tick_rate;
+
+	/* program the prescaler */
+	writew(CTRL_PRESCALER16, gpt_base + CR(CLKEVT));
+
+	tick_rate = clk_get_rate(gpt_clk);
+	tick_rate >>= CTRL_PRESCALER16;
+
+	clkevt.cpumask = cpumask_of(0);
+
+	clockevents_config_and_register(&clkevt, tick_rate, 3, 0xfff0);
+
+	if (request_irq(irq, spear_timer_interrupt, IRQF_TIMER, "timer", NULL))
+		pr_err("Failed to request irq %d (timer)\n", irq);
+}
+
+static const struct of_device_id timer_of_match[] __initconst = {
+	{ .compatible = "st,spear-timer", },
+	{ },
+};
+
+void __init spear_setup_of_timer(void)
+{
+	struct device_node *np;
+	int irq, ret;
+
+	np = of_find_matching_node(NULL, timer_of_match);
+	if (!np) {
+		pr_err("%s: No timer passed via DT\n", __func__);
+		return;
+	}
+
+	irq = irq_of_parse_and_map(np, 0);
+	if (!irq) {
+		pr_err("%s: No irq passed for timer via DT\n", __func__);
+		return;
+	}
+
+	gpt_base = of_iomap(np, 0);
+	if (!gpt_base) {
+		pr_err("%s: of iomap failed\n", __func__);
+		return;
+	}
+
+	gpt_clk = clk_get_sys("gpt0", NULL);
+	if (IS_ERR(gpt_clk)) {
+		pr_err("%s:couldn't get clk for gpt\n", __func__);
+		goto err_iomap;
+	}
+
+	ret = clk_prepare_enable(gpt_clk);
+	if (ret < 0) {
+		pr_err("%s:couldn't prepare-enable gpt clock\n", __func__);
+		goto err_prepare_enable_clk;
+	}
+
+	spear_clockevent_init(irq);
+	spear_clocksource_init();
+
+	return;
+
+err_prepare_enable_clk:
+	clk_put(gpt_clk);
+err_iomap:
+	iounmap(gpt_base);
+}