--- /dev/null
+/*
+ * Allwinner SoCs hstimer driver.
+ *
+ * Copyright (C) 2013 Maxime Ripard
+ *
+ * Maxime Ripard <maxime.ripard@free-electrons.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/delay.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/irqreturn.h>
+#include <linux/sched_clock.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+
+#define TIMER_IRQ_EN_REG 0x00
+#define TIMER_IRQ_EN(val) BIT(val)
+#define TIMER_IRQ_ST_REG 0x04
+#define TIMER_CTL_REG(val) (0x20 * (val) + 0x10)
+#define TIMER_CTL_ENABLE BIT(0)
+#define TIMER_CTL_RELOAD BIT(1)
+#define TIMER_CTL_CLK_PRES(val) (((val) & 0x7) << 4)
+#define TIMER_CTL_ONESHOT BIT(7)
+#define TIMER_INTVAL_LO_REG(val) (0x20 * (val) + 0x14)
+#define TIMER_INTVAL_HI_REG(val) (0x20 * (val) + 0x18)
+#define TIMER_CNTVAL_LO_REG(val) (0x20 * (val) + 0x1c)
+#define TIMER_CNTVAL_HI_REG(val) (0x20 * (val) + 0x20)
+
+#define TIMER_SYNC_TICKS 3
+
+static void __iomem *timer_base;
+static u32 ticks_per_jiffy;
+
+/*
+ * When we disable a timer, we need to wait at least for 2 cycles of
+ * the timer source clock. We will use for that the clocksource timer
+ * that is already setup and runs at the same frequency than the other
+ * timers, and we never will be disabled.
+ */
+static void sun5i_clkevt_sync(void)
+{
+ u32 old = readl(timer_base + TIMER_CNTVAL_LO_REG(1));
+
+ while ((old - readl(timer_base + TIMER_CNTVAL_LO_REG(1))) < TIMER_SYNC_TICKS)
+ cpu_relax();
+}
+
+static void sun5i_clkevt_time_stop(u8 timer)
+{
+ u32 val = readl(timer_base + TIMER_CTL_REG(timer));
+ writel(val & ~TIMER_CTL_ENABLE, timer_base + TIMER_CTL_REG(timer));
+
+ sun5i_clkevt_sync();
+}
+
+static void sun5i_clkevt_time_setup(u8 timer, u32 delay)
+{
+ writel(delay, timer_base + TIMER_INTVAL_LO_REG(timer));
+}
+
+static void sun5i_clkevt_time_start(u8 timer, bool periodic)
+{
+ u32 val = readl(timer_base + TIMER_CTL_REG(timer));
+
+ if (periodic)
+ val &= ~TIMER_CTL_ONESHOT;
+ else
+ val |= TIMER_CTL_ONESHOT;
+
+ writel(val | TIMER_CTL_ENABLE | TIMER_CTL_RELOAD,
+ timer_base + TIMER_CTL_REG(timer));
+}
+
+static void sun5i_clkevt_mode(enum clock_event_mode mode,
+ struct clock_event_device *clk)
+{
+ switch (mode) {
+ case CLOCK_EVT_MODE_PERIODIC:
+ sun5i_clkevt_time_stop(0);
+ sun5i_clkevt_time_setup(0, ticks_per_jiffy);
+ sun5i_clkevt_time_start(0, true);
+ break;
+ case CLOCK_EVT_MODE_ONESHOT:
+ sun5i_clkevt_time_stop(0);
+ sun5i_clkevt_time_start(0, false);
+ break;
+ case CLOCK_EVT_MODE_UNUSED:
+ case CLOCK_EVT_MODE_SHUTDOWN:
+ default:
+ sun5i_clkevt_time_stop(0);
+ break;
+ }
+}
+
+static int sun5i_clkevt_next_event(unsigned long evt,
+ struct clock_event_device *unused)
+{
+ sun5i_clkevt_time_stop(0);
+ sun5i_clkevt_time_setup(0, evt - TIMER_SYNC_TICKS);
+ sun5i_clkevt_time_start(0, false);
+
+ return 0;
+}
+
+static struct clock_event_device sun5i_clockevent = {
+ .name = "sun5i_tick",
+ .rating = 340,
+ .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
+ .set_mode = sun5i_clkevt_mode,
+ .set_next_event = sun5i_clkevt_next_event,
+};
+
+
+static irqreturn_t sun5i_timer_interrupt(int irq, void *dev_id)
+{
+ struct clock_event_device *evt = (struct clock_event_device *)dev_id;
+
+ writel(0x1, timer_base + TIMER_IRQ_ST_REG);
+ evt->event_handler(evt);
+
+ return IRQ_HANDLED;
+}
+
+static struct irqaction sun5i_timer_irq = {
+ .name = "sun5i_timer0",
+ .flags = IRQF_TIMER | IRQF_IRQPOLL,
+ .handler = sun5i_timer_interrupt,
+ .dev_id = &sun5i_clockevent,
+};
+
+static u32 sun5i_timer_sched_read(void)
+{
+ return ~readl(timer_base + TIMER_CNTVAL_LO_REG(1));
+}
+
+static void __init sun5i_timer_init(struct device_node *node)
+{
+ unsigned long rate;
+ struct clk *clk;
+ int ret, irq;
+ u32 val;
+
+ timer_base = of_iomap(node, 0);
+ if (!timer_base)
+ panic("Can't map registers");
+
+ irq = irq_of_parse_and_map(node, 0);
+ if (irq <= 0)
+ panic("Can't parse IRQ");
+
+ clk = of_clk_get(node, 0);
+ if (IS_ERR(clk))
+ panic("Can't get timer clock");
+ clk_prepare_enable(clk);
+ rate = clk_get_rate(clk);
+
+ writel(~0, timer_base + TIMER_INTVAL_LO_REG(1));
+ writel(TIMER_CTL_ENABLE | TIMER_CTL_RELOAD,
+ timer_base + TIMER_CTL_REG(1));
+
+ setup_sched_clock(sun5i_timer_sched_read, 32, rate);
+ clocksource_mmio_init(timer_base + TIMER_CNTVAL_LO_REG(1), node->name,
+ rate, 340, 32, clocksource_mmio_readl_down);
+
+ ticks_per_jiffy = DIV_ROUND_UP(rate, HZ);
+
+ ret = setup_irq(irq, &sun5i_timer_irq);
+ if (ret)
+ pr_warn("failed to setup irq %d\n", irq);
+
+ /* Enable timer0 interrupt */
+ val = readl(timer_base + TIMER_IRQ_EN_REG);
+ writel(val | TIMER_IRQ_EN(0), timer_base + TIMER_IRQ_EN_REG);
+
+ sun5i_clockevent.cpumask = cpu_possible_mask;
+ sun5i_clockevent.irq = irq;
+
+ clockevents_config_and_register(&sun5i_clockevent, rate,
+ TIMER_SYNC_TICKS, 0xffffffff);
+}
+CLOCKSOURCE_OF_DECLARE(sun5i_a13, "allwinner,sun5i-a13-hstimer",
+ sun5i_timer_init);
+CLOCKSOURCE_OF_DECLARE(sun7i_a20, "allwinner,sun7i-a20-hstimer",
+ sun5i_timer_init);
projects / karo-tx-linux.git / commitdiff