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-rw-r--r--drivers/clocksource/mxs_timer.c304
1 files changed, 304 insertions, 0 deletions
diff --git a/drivers/clocksource/mxs_timer.c b/drivers/clocksource/mxs_timer.c
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--- /dev/null
+++ b/drivers/clocksource/mxs_timer.c
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+/*
+ * Copyright (C) 2000-2001 Deep Blue Solutions
+ * Copyright (C) 2002 Shane Nay (shane@minirl.com)
+ * Copyright (C) 2006-2007 Pavel Pisa (ppisa@pikron.com)
+ * Copyright (C) 2008 Juergen Beisert (kernel@pengutronix.de)
+ * Copyright (C) 2010 Freescale Semiconductor, Inc. All Rights Reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+ * MA 02110-1301, USA.
+ */
+
+#include <linux/err.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/clockchips.h>
+#include <linux/clk.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/stmp_device.h>
+
+#include <asm/mach/time.h>
+#include <asm/sched_clock.h>
+
+/*
+ * There are 2 versions of the timrot on Freescale MXS-based SoCs.
+ * The v1 on MX23 only gets 16 bits counter, while v2 on MX28
+ * extends the counter to 32 bits.
+ *
+ * The implementation uses two timers, one for clock_event and
+ * another for clocksource. MX28 uses timrot 0 and 1, while MX23
+ * uses 0 and 2.
+ */
+
+#define MX23_TIMROT_VERSION_OFFSET 0x0a0
+#define MX28_TIMROT_VERSION_OFFSET 0x120
+#define BP_TIMROT_MAJOR_VERSION 24
+#define BV_TIMROT_VERSION_1 0x01
+#define BV_TIMROT_VERSION_2 0x02
+#define timrot_is_v1() (timrot_major_version == BV_TIMROT_VERSION_1)
+
+/*
+ * There are 4 registers for each timrotv2 instance, and 2 registers
+ * for each timrotv1. So address step 0x40 in macros below strides
+ * one instance of timrotv2 while two instances of timrotv1.
+ *
+ * As the result, HW_TIMROT_XXXn(1) defines the address of timrot1
+ * on MX28 while timrot2 on MX23.
+ */
+/* common between v1 and v2 */
+#define HW_TIMROT_ROTCTRL 0x00
+#define HW_TIMROT_TIMCTRLn(n) (0x20 + (n) * 0x40)
+/* v1 only */
+#define HW_TIMROT_TIMCOUNTn(n) (0x30 + (n) * 0x40)
+/* v2 only */
+#define HW_TIMROT_RUNNING_COUNTn(n) (0x30 + (n) * 0x40)
+#define HW_TIMROT_FIXED_COUNTn(n) (0x40 + (n) * 0x40)
+
+#define BM_TIMROT_TIMCTRLn_RELOAD (1 << 6)
+#define BM_TIMROT_TIMCTRLn_UPDATE (1 << 7)
+#define BM_TIMROT_TIMCTRLn_IRQ_EN (1 << 14)
+#define BM_TIMROT_TIMCTRLn_IRQ (1 << 15)
+#define BP_TIMROT_TIMCTRLn_SELECT 0
+#define BV_TIMROTv1_TIMCTRLn_SELECT__32KHZ_XTAL 0x8
+#define BV_TIMROTv2_TIMCTRLn_SELECT__32KHZ_XTAL 0xb
+#define BV_TIMROTv2_TIMCTRLn_SELECT__TICK_ALWAYS 0xf
+
+static struct clock_event_device mxs_clockevent_device;
+static enum clock_event_mode mxs_clockevent_mode = CLOCK_EVT_MODE_UNUSED;
+
+static void __iomem *mxs_timrot_base;
+static u32 timrot_major_version;
+
+static inline void timrot_irq_disable(void)
+{
+ __raw_writel(BM_TIMROT_TIMCTRLn_IRQ_EN, mxs_timrot_base +
+ HW_TIMROT_TIMCTRLn(0) + STMP_OFFSET_REG_CLR);
+}
+
+static inline void timrot_irq_enable(void)
+{
+ __raw_writel(BM_TIMROT_TIMCTRLn_IRQ_EN, mxs_timrot_base +
+ HW_TIMROT_TIMCTRLn(0) + STMP_OFFSET_REG_SET);
+}
+
+static void timrot_irq_acknowledge(void)
+{
+ __raw_writel(BM_TIMROT_TIMCTRLn_IRQ, mxs_timrot_base +
+ HW_TIMROT_TIMCTRLn(0) + STMP_OFFSET_REG_CLR);
+}
+
+static cycle_t timrotv1_get_cycles(struct clocksource *cs)
+{
+ return ~((__raw_readl(mxs_timrot_base + HW_TIMROT_TIMCOUNTn(1))
+ & 0xffff0000) >> 16);
+}
+
+static int timrotv1_set_next_event(unsigned long evt,
+ struct clock_event_device *dev)
+{
+ /* timrot decrements the count */
+ __raw_writel(evt, mxs_timrot_base + HW_TIMROT_TIMCOUNTn(0));
+
+ return 0;
+}
+
+static int timrotv2_set_next_event(unsigned long evt,
+ struct clock_event_device *dev)
+{
+ /* timrot decrements the count */
+ __raw_writel(evt, mxs_timrot_base + HW_TIMROT_FIXED_COUNTn(0));
+
+ return 0;
+}
+
+static irqreturn_t mxs_timer_interrupt(int irq, void *dev_id)
+{
+ struct clock_event_device *evt = dev_id;
+
+ timrot_irq_acknowledge();
+ evt->event_handler(evt);
+
+ return IRQ_HANDLED;
+}
+
+static struct irqaction mxs_timer_irq = {
+ .name = "MXS Timer Tick",
+ .dev_id = &mxs_clockevent_device,
+ .flags = IRQF_TIMER | IRQF_IRQPOLL,
+ .handler = mxs_timer_interrupt,
+};
+
+#ifdef DEBUG
+static const char *clock_event_mode_label[] const = {
+ [CLOCK_EVT_MODE_PERIODIC] = "CLOCK_EVT_MODE_PERIODIC",
+ [CLOCK_EVT_MODE_ONESHOT] = "CLOCK_EVT_MODE_ONESHOT",
+ [CLOCK_EVT_MODE_SHUTDOWN] = "CLOCK_EVT_MODE_SHUTDOWN",
+ [CLOCK_EVT_MODE_UNUSED] = "CLOCK_EVT_MODE_UNUSED"
+};
+#endif /* DEBUG */
+
+static void mxs_set_mode(enum clock_event_mode mode,
+ struct clock_event_device *evt)
+{
+ /* Disable interrupt in timer module */
+ timrot_irq_disable();
+
+ if (mode != mxs_clockevent_mode) {
+ /* Set event time into the furthest future */
+ if (timrot_is_v1())
+ __raw_writel(0xffff,
+ mxs_timrot_base + HW_TIMROT_TIMCOUNTn(1));
+ else
+ __raw_writel(0xffffffff,
+ mxs_timrot_base + HW_TIMROT_FIXED_COUNTn(1));
+
+ /* Clear pending interrupt */
+ timrot_irq_acknowledge();
+ }
+
+#ifdef DEBUG
+ pr_info("%s: changing mode from %s to %s\n", __func__,
+ clock_event_mode_label[mxs_clockevent_mode],
+ clock_event_mode_label[mode]);
+#endif /* DEBUG */
+
+ /* Remember timer mode */
+ mxs_clockevent_mode = mode;
+
+ switch (mode) {
+ case CLOCK_EVT_MODE_PERIODIC:
+ pr_err("%s: Periodic mode is not implemented\n", __func__);
+ break;
+ case CLOCK_EVT_MODE_ONESHOT:
+ timrot_irq_enable();
+ break;
+ case CLOCK_EVT_MODE_SHUTDOWN:
+ case CLOCK_EVT_MODE_UNUSED:
+ case CLOCK_EVT_MODE_RESUME:
+ /* Left event sources disabled, no more interrupts appear */
+ break;
+ }
+}
+
+static struct clock_event_device mxs_clockevent_device = {
+ .name = "mxs_timrot",
+ .features = CLOCK_EVT_FEAT_ONESHOT,
+ .set_mode = mxs_set_mode,
+ .set_next_event = timrotv2_set_next_event,
+ .rating = 200,
+};
+
+static int __init mxs_clockevent_init(struct clk *timer_clk)
+{
+ if (timrot_is_v1())
+ mxs_clockevent_device.set_next_event = timrotv1_set_next_event;
+ mxs_clockevent_device.cpumask = cpumask_of(0);
+ clockevents_config_and_register(&mxs_clockevent_device,
+ clk_get_rate(timer_clk),
+ timrot_is_v1() ? 0xf : 0x2,
+ timrot_is_v1() ? 0xfffe : 0xfffffffe);
+
+ return 0;
+}
+
+static struct clocksource clocksource_mxs = {
+ .name = "mxs_timer",
+ .rating = 200,
+ .read = timrotv1_get_cycles,
+ .mask = CLOCKSOURCE_MASK(16),
+ .flags = CLOCK_SOURCE_IS_CONTINUOUS,
+};
+
+static u32 notrace mxs_read_sched_clock_v2(void)
+{
+ return ~readl_relaxed(mxs_timrot_base + HW_TIMROT_RUNNING_COUNTn(1));
+}
+
+static int __init mxs_clocksource_init(struct clk *timer_clk)
+{
+ unsigned int c = clk_get_rate(timer_clk);
+
+ if (timrot_is_v1())
+ clocksource_register_hz(&clocksource_mxs, c);
+ else {
+ clocksource_mmio_init(mxs_timrot_base + HW_TIMROT_RUNNING_COUNTn(1),
+ "mxs_timer", c, 200, 32, clocksource_mmio_readl_down);
+ setup_sched_clock(mxs_read_sched_clock_v2, 32, c);
+ }
+
+ return 0;
+}
+
+static void __init mxs_timer_init(struct device_node *np)
+{
+ struct clk *timer_clk;
+ int irq;
+
+ mxs_timrot_base = of_iomap(np, 0);
+ WARN_ON(!mxs_timrot_base);
+
+ timer_clk = of_clk_get(np, 0);
+ if (IS_ERR(timer_clk)) {
+ pr_err("%s: failed to get clk\n", __func__);
+ return;
+ }
+
+ clk_prepare_enable(timer_clk);
+
+ /*
+ * Initialize timers to a known state
+ */
+ stmp_reset_block(mxs_timrot_base + HW_TIMROT_ROTCTRL);
+
+ /* get timrot version */
+ timrot_major_version = __raw_readl(mxs_timrot_base +
+ (of_device_is_compatible(np, "fsl,imx23-timrot") ?
+ MX23_TIMROT_VERSION_OFFSET :
+ MX28_TIMROT_VERSION_OFFSET));
+ timrot_major_version >>= BP_TIMROT_MAJOR_VERSION;
+
+ /* one for clock_event */
+ __raw_writel((timrot_is_v1() ?
+ BV_TIMROTv1_TIMCTRLn_SELECT__32KHZ_XTAL :
+ BV_TIMROTv2_TIMCTRLn_SELECT__TICK_ALWAYS) |
+ BM_TIMROT_TIMCTRLn_UPDATE |
+ BM_TIMROT_TIMCTRLn_IRQ_EN,
+ mxs_timrot_base + HW_TIMROT_TIMCTRLn(0));
+
+ /* another for clocksource */
+ __raw_writel((timrot_is_v1() ?
+ BV_TIMROTv1_TIMCTRLn_SELECT__32KHZ_XTAL :
+ BV_TIMROTv2_TIMCTRLn_SELECT__TICK_ALWAYS) |
+ BM_TIMROT_TIMCTRLn_RELOAD,
+ mxs_timrot_base + HW_TIMROT_TIMCTRLn(1));
+
+ /* set clocksource timer fixed count to the maximum */
+ if (timrot_is_v1())
+ __raw_writel(0xffff,
+ mxs_timrot_base + HW_TIMROT_TIMCOUNTn(1));
+ else
+ __raw_writel(0xffffffff,
+ mxs_timrot_base + HW_TIMROT_FIXED_COUNTn(1));
+
+ /* init and register the timer to the framework */
+ mxs_clocksource_init(timer_clk);
+ mxs_clockevent_init(timer_clk);
+
+ /* Make irqs happen */
+ irq = irq_of_parse_and_map(np, 0);
+ setup_irq(irq, &mxs_timer_irq);
+}
+CLOCKSOURCE_OF_DECLARE(mxs, "fsl,timrot", mxs_timer_init);
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