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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
commit2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch)
tree848558de17fb3008cdf4d861b01ac7781903ce39 /arch/arm/mach-omap1/timer32k.c
parentInitial commit. (diff)
downloadlinux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz
linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip
Adding upstream version 6.1.76.upstream/6.1.76
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'arch/arm/mach-omap1/timer32k.c')
-rw-r--r--arch/arm/mach-omap1/timer32k.c282
1 files changed, 282 insertions, 0 deletions
diff --git a/arch/arm/mach-omap1/timer32k.c b/arch/arm/mach-omap1/timer32k.c
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+/*
+ * linux/arch/arm/mach-omap1/timer32k.c
+ *
+ * OMAP 32K Timer
+ *
+ * Copyright (C) 2004 - 2005 Nokia Corporation
+ * Partial timer rewrite and additional dynamic tick timer support by
+ * Tony Lindgen <tony@atomide.com> and
+ * Tuukka Tikkanen <tuukka.tikkanen@elektrobit.com>
+ * OMAP Dual-mode timer framework support by Timo Teras
+ *
+ * MPU timer code based on the older MPU timer code for OMAP
+ * Copyright (C) 2000 RidgeRun, Inc.
+ * Author: Greg Lonnon <glonnon@ridgerun.com>
+ *
+ * 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 SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN
+ * NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
+ * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * 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.,
+ * 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/delay.h>
+#include <linux/interrupt.h>
+#include <linux/sched.h>
+#include <linux/spinlock.h>
+#include <linux/err.h>
+#include <linux/clk.h>
+#include <linux/clocksource.h>
+#include <linux/clockchips.h>
+#include <linux/io.h>
+#include <linux/sched_clock.h>
+
+#include <asm/irq.h>
+#include <asm/mach/irq.h>
+#include <asm/mach/time.h>
+
+#include "hardware.h"
+#include "common.h"
+
+/*
+ * ---------------------------------------------------------------------------
+ * 32KHz OS timer
+ *
+ * This currently works only on 16xx, as 1510 does not have the continuous
+ * 32KHz synchronous timer. The 32KHz synchronous timer is used to keep track
+ * of time in addition to the 32KHz OS timer. Using only the 32KHz OS timer
+ * on 1510 would be possible, but the timer would not be as accurate as
+ * with the 32KHz synchronized timer.
+ * ---------------------------------------------------------------------------
+ */
+
+/* 16xx specific defines */
+#define OMAP1_32K_TIMER_BASE 0xfffb9000
+#define OMAP1_32KSYNC_TIMER_BASE 0xfffbc400
+#define OMAP1_32K_TIMER_CR 0x08
+#define OMAP1_32K_TIMER_TVR 0x00
+#define OMAP1_32K_TIMER_TCR 0x04
+
+#define OMAP_32K_TICKS_PER_SEC (32768)
+
+/*
+ * TRM says 1 / HZ = ( TVR + 1) / 32768, so TRV = (32768 / HZ) - 1
+ * so with HZ = 128, TVR = 255.
+ */
+#define OMAP_32K_TIMER_TICK_PERIOD ((OMAP_32K_TICKS_PER_SEC / HZ) - 1)
+
+#define JIFFIES_TO_HW_TICKS(nr_jiffies, clock_rate) \
+ (((nr_jiffies) * (clock_rate)) / HZ)
+
+static inline void omap_32k_timer_write(int val, int reg)
+{
+ omap_writew(val, OMAP1_32K_TIMER_BASE + reg);
+}
+
+static inline void omap_32k_timer_start(unsigned long load_val)
+{
+ if (!load_val)
+ load_val = 1;
+ omap_32k_timer_write(load_val, OMAP1_32K_TIMER_TVR);
+ omap_32k_timer_write(0x0f, OMAP1_32K_TIMER_CR);
+}
+
+static inline void omap_32k_timer_stop(void)
+{
+ omap_32k_timer_write(0x0, OMAP1_32K_TIMER_CR);
+}
+
+#define omap_32k_timer_ack_irq()
+
+static int omap_32k_timer_set_next_event(unsigned long delta,
+ struct clock_event_device *dev)
+{
+ omap_32k_timer_start(delta);
+
+ return 0;
+}
+
+static int omap_32k_timer_shutdown(struct clock_event_device *evt)
+{
+ omap_32k_timer_stop();
+ return 0;
+}
+
+static int omap_32k_timer_set_periodic(struct clock_event_device *evt)
+{
+ omap_32k_timer_stop();
+ omap_32k_timer_start(OMAP_32K_TIMER_TICK_PERIOD);
+ return 0;
+}
+
+static struct clock_event_device clockevent_32k_timer = {
+ .name = "32k-timer",
+ .features = CLOCK_EVT_FEAT_PERIODIC |
+ CLOCK_EVT_FEAT_ONESHOT,
+ .set_next_event = omap_32k_timer_set_next_event,
+ .set_state_shutdown = omap_32k_timer_shutdown,
+ .set_state_periodic = omap_32k_timer_set_periodic,
+ .set_state_oneshot = omap_32k_timer_shutdown,
+ .tick_resume = omap_32k_timer_shutdown,
+};
+
+static irqreturn_t omap_32k_timer_interrupt(int irq, void *dev_id)
+{
+ struct clock_event_device *evt = &clockevent_32k_timer;
+ omap_32k_timer_ack_irq();
+
+ evt->event_handler(evt);
+
+ return IRQ_HANDLED;
+}
+
+static __init void omap_init_32k_timer(void)
+{
+ if (request_irq(INT_OS_TIMER, omap_32k_timer_interrupt,
+ IRQF_TIMER | IRQF_IRQPOLL, "32KHz timer", NULL))
+ pr_err("Failed to request irq %d(32KHz timer)\n", INT_OS_TIMER);
+
+ clockevent_32k_timer.cpumask = cpumask_of(0);
+ clockevents_config_and_register(&clockevent_32k_timer,
+ OMAP_32K_TICKS_PER_SEC, 1, 0xfffffffe);
+}
+
+/* OMAP2_32KSYNCNT_CR_OFF: offset of 32ksync counter register */
+#define OMAP2_32KSYNCNT_REV_OFF 0x0
+#define OMAP2_32KSYNCNT_REV_SCHEME (0x3 << 30)
+#define OMAP2_32KSYNCNT_CR_OFF_LOW 0x10
+#define OMAP2_32KSYNCNT_CR_OFF_HIGH 0x30
+
+/*
+ * 32KHz clocksource ... always available, on pretty most chips except
+ * OMAP 730 and 1510. Other timers could be used as clocksources, with
+ * higher resolution in free-running counter modes (e.g. 12 MHz xtal),
+ * but systems won't necessarily want to spend resources that way.
+ */
+static void __iomem *sync32k_cnt_reg;
+
+static u64 notrace omap_32k_read_sched_clock(void)
+{
+ return sync32k_cnt_reg ? readl_relaxed(sync32k_cnt_reg) : 0;
+}
+
+static struct timespec64 persistent_ts;
+static cycles_t cycles;
+static unsigned int persistent_mult, persistent_shift;
+
+/**
+ * omap_read_persistent_clock64 - Return time from a persistent clock.
+ * @ts: &struct timespec64 for the returned time
+ *
+ * Reads the time from a source which isn't disabled during PM, the
+ * 32k sync timer. Convert the cycles elapsed since last read into
+ * nsecs and adds to a monotonically increasing timespec64.
+ */
+static void omap_read_persistent_clock64(struct timespec64 *ts)
+{
+ unsigned long long nsecs;
+ cycles_t last_cycles;
+
+ last_cycles = cycles;
+ cycles = sync32k_cnt_reg ? readl_relaxed(sync32k_cnt_reg) : 0;
+
+ nsecs = clocksource_cyc2ns(cycles - last_cycles,
+ persistent_mult, persistent_shift);
+
+ timespec64_add_ns(&persistent_ts, nsecs);
+
+ *ts = persistent_ts;
+}
+
+/**
+ * omap_init_clocksource_32k - setup and register counter 32k as a
+ * kernel clocksource
+ * @vbase: base addr of counter_32k module
+ *
+ * Returns: %0 upon success or negative error code upon failure.
+ *
+ */
+static int __init omap_init_clocksource_32k(void __iomem *vbase)
+{
+ int ret;
+
+ /*
+ * 32k sync Counter IP register offsets vary between the
+ * highlander version and the legacy ones.
+ * The 'SCHEME' bits(30-31) of the revision register is used
+ * to identify the version.
+ */
+ if (readl_relaxed(vbase + OMAP2_32KSYNCNT_REV_OFF) &
+ OMAP2_32KSYNCNT_REV_SCHEME)
+ sync32k_cnt_reg = vbase + OMAP2_32KSYNCNT_CR_OFF_HIGH;
+ else
+ sync32k_cnt_reg = vbase + OMAP2_32KSYNCNT_CR_OFF_LOW;
+
+ /*
+ * 120000 rough estimate from the calculations in
+ * __clocksource_update_freq_scale.
+ */
+ clocks_calc_mult_shift(&persistent_mult, &persistent_shift,
+ 32768, NSEC_PER_SEC, 120000);
+
+ ret = clocksource_mmio_init(sync32k_cnt_reg, "32k_counter", 32768,
+ 250, 32, clocksource_mmio_readl_up);
+ if (ret) {
+ pr_err("32k_counter: can't register clocksource\n");
+ return ret;
+ }
+
+ sched_clock_register(omap_32k_read_sched_clock, 32, 32768);
+ register_persistent_clock(omap_read_persistent_clock64);
+ pr_info("OMAP clocksource: 32k_counter at 32768 Hz\n");
+
+ return 0;
+}
+
+/*
+ * ---------------------------------------------------------------------------
+ * Timer initialization
+ * ---------------------------------------------------------------------------
+ */
+int __init omap_32k_timer_init(void)
+{
+ int ret = -ENODEV;
+
+ if (cpu_is_omap16xx()) {
+ void __iomem *base;
+ struct clk *sync32k_ick;
+
+ base = ioremap(OMAP1_32KSYNC_TIMER_BASE, SZ_1K);
+ if (!base) {
+ pr_err("32k_counter: failed to map base addr\n");
+ return -ENODEV;
+ }
+
+ sync32k_ick = clk_get(NULL, "omap_32ksync_ick");
+ if (!IS_ERR(sync32k_ick))
+ clk_prepare_enable(sync32k_ick);
+
+ ret = omap_init_clocksource_32k(base);
+ }
+
+ if (!ret)
+ omap_init_32k_timer();
+
+ return ret;
+}