--- /dev/null
+/*
+ * SuperH Timer Support - CMT
+ *
+ * Copyright (C) 2008 Magnus Damm
+ *
+ * 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
+ *
+ * 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#include <linux/init.h>
+#include <linux/bootmem.h>
+#include <linux/platform_device.h>
+#include <linux/spinlock.h>
+#include <linux/interrupt.h>
+#include <linux/ioport.h>
+#include <linux/io.h>
+#include <linux/clk.h>
+#include <linux/irq.h>
+#include <linux/err.h>
+#include <linux/clocksource.h>
+#include <linux/clockchips.h>
+#include <linux/sh_cmt.h>
+
+struct sh_cmt_priv {
+ void __iomem *mapbase;
+ struct clk *clk;
+ unsigned long width; /* 16 or 32 bit version of hardware block */
+ unsigned long overflow_bit;
+ unsigned long clear_bits;
+ struct irqaction irqaction;
+ struct platform_device *pdev;
+
+ unsigned long flags;
+ unsigned long match_value;
+ unsigned long next_match_value;
+ unsigned long max_match_value;
+ unsigned long rate;
+ spinlock_t lock;
+ struct clock_event_device ced;
+ unsigned long total_cycles;
+};
+
+static DEFINE_SPINLOCK(sh_cmt_lock);
+
+#define CMSTR -1 /* shared register */
+#define CMCSR 0 /* channel register */
+#define CMCNT 1 /* channel register */
+#define CMCOR 2 /* channel register */
+
+static inline unsigned long sh_cmt_read(struct sh_cmt_priv *p, int reg_nr)
+{
+ struct sh_cmt_config *cfg = p->pdev->dev.platform_data;
+ void __iomem *base = p->mapbase;
+ unsigned long offs;
+
+ if (reg_nr == CMSTR) {
+ offs = 0;
+ base -= cfg->channel_offset;
+ } else
+ offs = reg_nr;
+
+ if (p->width == 16)
+ offs <<= 1;
+ else {
+ offs <<= 2;
+ if ((reg_nr == CMCNT) || (reg_nr == CMCOR))
+ return ioread32(base + offs);
+ }
+
+ return ioread16(base + offs);
+}
+
+static inline void sh_cmt_write(struct sh_cmt_priv *p, int reg_nr,
+ unsigned long value)
+{
+ struct sh_cmt_config *cfg = p->pdev->dev.platform_data;
+ void __iomem *base = p->mapbase;
+ unsigned long offs;
+
+ if (reg_nr == CMSTR) {
+ offs = 0;
+ base -= cfg->channel_offset;
+ } else
+ offs = reg_nr;
+
+ if (p->width == 16)
+ offs <<= 1;
+ else {
+ offs <<= 2;
+ if ((reg_nr == CMCNT) || (reg_nr == CMCOR)) {
+ iowrite32(value, base + offs);
+ return;
+ }
+ }
+
+ iowrite16(value, base + offs);
+}
+
+static unsigned long sh_cmt_get_counter(struct sh_cmt_priv *p,
+ int *has_wrapped)
+{
+ unsigned long v1, v2, v3;
+
+ /* Make sure the timer value is stable. Stolen from acpi_pm.c */
+ do {
+ v1 = sh_cmt_read(p, CMCNT);
+ v2 = sh_cmt_read(p, CMCNT);
+ v3 = sh_cmt_read(p, CMCNT);
+ } while (unlikely((v1 > v2 && v1 < v3) || (v2 > v3 && v2 < v1)
+ || (v3 > v1 && v3 < v2)));
+
+ *has_wrapped = sh_cmt_read(p, CMCSR) & p->overflow_bit;
+ return v2;
+}
+
+
+static void sh_cmt_start_stop_ch(struct sh_cmt_priv *p, int start)
+{
+ struct sh_cmt_config *cfg = p->pdev->dev.platform_data;
+ unsigned long flags, value;
+
+ /* start stop register shared by multiple timer channels */
+ spin_lock_irqsave(&sh_cmt_lock, flags);
+ value = sh_cmt_read(p, CMSTR);
+
+ if (start)
+ value |= 1 << cfg->timer_bit;
+ else
+ value &= ~(1 << cfg->timer_bit);
+
+ sh_cmt_write(p, CMSTR, value);
+ spin_unlock_irqrestore(&sh_cmt_lock, flags);
+}
+
+static int sh_cmt_enable(struct sh_cmt_priv *p, unsigned long *rate)
+{
+ struct sh_cmt_config *cfg = p->pdev->dev.platform_data;
+ int ret;
+
+ /* enable clock */
+ ret = clk_enable(p->clk);
+ if (ret) {
+ pr_err("sh_cmt: cannot enable clock \"%s\"\n", cfg->clk);
+ return ret;
+ }
+ *rate = clk_get_rate(p->clk) / 8;
+
+ /* make sure channel is disabled */
+ sh_cmt_start_stop_ch(p, 0);
+
+ /* configure channel, periodic mode and maximum timeout */
+ if (p->width == 16)
+ sh_cmt_write(p, CMCSR, 0);
+ else
+ sh_cmt_write(p, CMCSR, 0x01a4);
+
+ sh_cmt_write(p, CMCOR, 0xffffffff);
+ sh_cmt_write(p, CMCNT, 0);
+
+ /* enable channel */
+ sh_cmt_start_stop_ch(p, 1);
+ return 0;
+}
+
+static void sh_cmt_disable(struct sh_cmt_priv *p)
+{
+ /* disable channel */
+ sh_cmt_start_stop_ch(p, 0);
+
+ /* stop clock */
+ clk_disable(p->clk);
+}
+
+/* private flags */
+#define FLAG_CLOCKEVENT (1 << 0)
+#define FLAG_CLOCKSOURCE (1 << 1)
+#define FLAG_REPROGRAM (1 << 2)
+#define FLAG_SKIPEVENT (1 << 3)
+#define FLAG_IRQCONTEXT (1 << 4)
+
+static void sh_cmt_clock_event_program_verify(struct sh_cmt_priv *p,
+ int absolute)
+{
+ unsigned long new_match;
+ unsigned long value = p->next_match_value;
+ unsigned long delay = 0;
+ unsigned long now = 0;
+ int has_wrapped;
+
+ now = sh_cmt_get_counter(p, &has_wrapped);
+ p->flags |= FLAG_REPROGRAM; /* force reprogram */
+
+ if (has_wrapped) {
+ /* we're competing with the interrupt handler.
+ * -> let the interrupt handler reprogram the timer.
+ * -> interrupt number two handles the event.
+ */
+ p->flags |= FLAG_SKIPEVENT;
+ return;
+ }
+
+ if (absolute)
+ now = 0;
+
+ do {
+ /* reprogram the timer hardware,
+ * but don't save the new match value yet.
+ */
+ new_match = now + value + delay;
+ if (new_match > p->max_match_value)
+ new_match = p->max_match_value;
+
+ sh_cmt_write(p, CMCOR, new_match);
+
+ now = sh_cmt_get_counter(p, &has_wrapped);
+ if (has_wrapped && (new_match > p->match_value)) {
+ /* we are changing to a greater match value,
+ * so this wrap must be caused by the counter
+ * matching the old value.
+ * -> first interrupt reprograms the timer.
+ * -> interrupt number two handles the event.
+ */
+ p->flags |= FLAG_SKIPEVENT;
+ break;
+ }
+
+ if (has_wrapped) {
+ /* we are changing to a smaller match value,
+ * so the wrap must be caused by the counter
+ * matching the new value.
+ * -> save programmed match value.
+ * -> let isr handle the event.
+ */
+ p->match_value = new_match;
+ break;
+ }
+
+ /* be safe: verify hardware settings */
+ if (now < new_match) {
+ /* timer value is below match value, all good.
+ * this makes sure we won't miss any match events.
+ * -> save programmed match value.
+ * -> let isr handle the event.
+ */
+ p->match_value = new_match;
+ break;
+ }
+
+ /* the counter has reached a value greater
+ * than our new match value. and since the
+ * has_wrapped flag isn't set we must have
+ * programmed a too close event.
+ * -> increase delay and retry.
+ */
+ if (delay)
+ delay <<= 1;
+ else
+ delay = 1;
+
+ if (!delay)
+ pr_warning("sh_cmt: too long delay\n");
+
+ } while (delay);
+}
+
+static void sh_cmt_set_next(struct sh_cmt_priv *p, unsigned long delta)
+{
+ unsigned long flags;
+
+ if (delta > p->max_match_value)
+ pr_warning("sh_cmt: delta out of range\n");
+
+ spin_lock_irqsave(&p->lock, flags);
+ p->next_match_value = delta;
+ sh_cmt_clock_event_program_verify(p, 0);
+ spin_unlock_irqrestore(&p->lock, flags);
+}
+
+static irqreturn_t sh_cmt_interrupt(int irq, void *dev_id)
+{
+ struct sh_cmt_priv *p = dev_id;
+
+ /* clear flags */
+ sh_cmt_write(p, CMCSR, sh_cmt_read(p, CMCSR) & p->clear_bits);
+
+ /* update clock source counter to begin with if enabled
+ * the wrap flag should be cleared by the timer specific
+ * isr before we end up here.
+ */
+ if (p->flags & FLAG_CLOCKSOURCE)
+ p->total_cycles += p->match_value;
+
+ if (!(p->flags & FLAG_REPROGRAM))
+ p->next_match_value = p->max_match_value;
+
+ p->flags |= FLAG_IRQCONTEXT;
+
+ if (p->flags & FLAG_CLOCKEVENT) {
+ if (!(p->flags & FLAG_SKIPEVENT)) {
+ if (p->ced.mode == CLOCK_EVT_MODE_ONESHOT) {
+ p->next_match_value = p->max_match_value;
+ p->flags |= FLAG_REPROGRAM;
+ }
+
+ p->ced.event_handler(&p->ced);
+ }
+ }
+
+ p->flags &= ~FLAG_SKIPEVENT;
+
+ if (p->flags & FLAG_REPROGRAM) {
+ p->flags &= ~FLAG_REPROGRAM;
+ sh_cmt_clock_event_program_verify(p, 1);
+
+ if (p->flags & FLAG_CLOCKEVENT)
+ if ((p->ced.mode == CLOCK_EVT_MODE_SHUTDOWN)
+ || (p->match_value == p->next_match_value))
+ p->flags &= ~FLAG_REPROGRAM;
+ }
+
+ p->flags &= ~FLAG_IRQCONTEXT;
+
+ return IRQ_HANDLED;
+}
+
+static int sh_cmt_start(struct sh_cmt_priv *p, unsigned long flag)
+{
+ int ret = 0;
+ unsigned long flags;
+
+ spin_lock_irqsave(&p->lock, flags);
+
+ if (!(p->flags & (FLAG_CLOCKEVENT | FLAG_CLOCKSOURCE)))
+ ret = sh_cmt_enable(p, &p->rate);
+
+ if (ret)
+ goto out;
+ p->flags |= flag;
+
+ /* setup timeout if no clockevent */
+ if ((flag == FLAG_CLOCKSOURCE) && (!(p->flags & FLAG_CLOCKEVENT)))
+ sh_cmt_set_next(p, p->max_match_value);
+ out:
+ spin_unlock_irqrestore(&p->lock, flags);
+
+ return ret;
+}
+
+static void sh_cmt_stop(struct sh_cmt_priv *p, unsigned long flag)
+{
+ unsigned long flags;
+ unsigned long f;
+
+ spin_lock_irqsave(&p->lock, flags);
+
+ f = p->flags & (FLAG_CLOCKEVENT | FLAG_CLOCKSOURCE);
+ p->flags &= ~flag;
+
+ if (f && !(p->flags & (FLAG_CLOCKEVENT | FLAG_CLOCKSOURCE)))
+ sh_cmt_disable(p);
+
+ /* adjust the timeout to maximum if only clocksource left */
+ if ((flag == FLAG_CLOCKEVENT) && (p->flags & FLAG_CLOCKSOURCE))
+ sh_cmt_set_next(p, p->max_match_value);
+
+ spin_unlock_irqrestore(&p->lock, flags);
+}
+
+static struct sh_cmt_priv *ced_to_sh_cmt(struct clock_event_device *ced)
+{
+ return container_of(ced, struct sh_cmt_priv, ced);
+}
+
+static void sh_cmt_clock_event_start(struct sh_cmt_priv *p, int periodic)
+{
+ struct clock_event_device *ced = &p->ced;
+
+ sh_cmt_start(p, FLAG_CLOCKEVENT);
+
+ /* TODO: calculate good shift from rate and counter bit width */
+
+ ced->shift = 32;
+ ced->mult = div_sc(p->rate, NSEC_PER_SEC, ced->shift);
+ ced->max_delta_ns = clockevent_delta2ns(p->max_match_value, ced);
+ ced->min_delta_ns = clockevent_delta2ns(0x1f, ced);
+
+ if (periodic)
+ sh_cmt_set_next(p, (p->rate + HZ/2) / HZ);
+ else
+ sh_cmt_set_next(p, p->max_match_value);
+}
+
+static void sh_cmt_clock_event_mode(enum clock_event_mode mode,
+ struct clock_event_device *ced)
+{
+ struct sh_cmt_priv *p = ced_to_sh_cmt(ced);
+
+ /* deal with old setting first */
+ switch (ced->mode) {
+ case CLOCK_EVT_MODE_PERIODIC:
+ case CLOCK_EVT_MODE_ONESHOT:
+ sh_cmt_stop(p, FLAG_CLOCKEVENT);
+ break;
+ default:
+ break;
+ }
+
+ switch (mode) {
+ case CLOCK_EVT_MODE_PERIODIC:
+ pr_info("sh_cmt: %s used for periodic clock events\n",
+ ced->name);
+ sh_cmt_clock_event_start(p, 1);
+ break;
+ case CLOCK_EVT_MODE_ONESHOT:
+ pr_info("sh_cmt: %s used for oneshot clock events\n",
+ ced->name);
+ sh_cmt_clock_event_start(p, 0);
+ break;
+ case CLOCK_EVT_MODE_SHUTDOWN:
+ case CLOCK_EVT_MODE_UNUSED:
+ sh_cmt_stop(p, FLAG_CLOCKEVENT);
+ break;
+ default:
+ break;
+ }
+}
+
+static int sh_cmt_clock_event_next(unsigned long delta,
+ struct clock_event_device *ced)
+{
+ struct sh_cmt_priv *p = ced_to_sh_cmt(ced);
+
+ BUG_ON(ced->mode != CLOCK_EVT_MODE_ONESHOT);
+ if (likely(p->flags & FLAG_IRQCONTEXT))
+ p->next_match_value = delta;
+ else
+ sh_cmt_set_next(p, delta);
+
+ return 0;
+}
+
+static void sh_cmt_register_clockevent(struct sh_cmt_priv *p,
+ char *name, unsigned long rating)
+{
+ struct clock_event_device *ced = &p->ced;
+
+ memset(ced, 0, sizeof(*ced));
+
+ ced->name = name;
+ ced->features = CLOCK_EVT_FEAT_PERIODIC;
+ ced->features |= CLOCK_EVT_FEAT_ONESHOT;
+ ced->rating = rating;
+ ced->cpumask = cpumask_of(0);
+ ced->set_next_event = sh_cmt_clock_event_next;
+ ced->set_mode = sh_cmt_clock_event_mode;
+
+ pr_info("sh_cmt: %s used for clock events\n", ced->name);
+ ced->mult = 1; /* work around misplaced WARN_ON() in clockevents.c */
+ clockevents_register_device(ced);
+}
+
+int sh_cmt_register(struct sh_cmt_priv *p, char *name,
+ unsigned long clockevent_rating,
+ unsigned long clocksource_rating)
+{
+ if (p->width == (sizeof(p->max_match_value) * 8))
+ p->max_match_value = ~0;
+ else
+ p->max_match_value = (1 << p->width) - 1;
+
+ p->match_value = p->max_match_value;
+ spin_lock_init(&p->lock);
+
+ if (clockevent_rating)
+ sh_cmt_register_clockevent(p, name, clockevent_rating);
+
+ return 0;
+}
+
+static int sh_cmt_setup(struct sh_cmt_priv *p, struct platform_device *pdev)
+{
+ struct sh_cmt_config *cfg = pdev->dev.platform_data;
+ struct resource *res;
+ int irq, ret;
+ ret = -ENXIO;
+
+ memset(p, 0, sizeof(*p));
+ p->pdev = pdev;
+
+ if (!cfg) {
+ dev_err(&p->pdev->dev, "missing platform data\n");
+ goto err0;
+ }
+
+ platform_set_drvdata(pdev, p);
+
+ res = platform_get_resource(p->pdev, IORESOURCE_MEM, 0);
+ if (!res) {
+ dev_err(&p->pdev->dev, "failed to get I/O memory\n");
+ goto err0;
+ }
+
+ irq = platform_get_irq(p->pdev, 0);
+ if (irq < 0) {
+ dev_err(&p->pdev->dev, "failed to get irq\n");
+ goto err0;
+ }
+
+ /* map memory, let mapbase point to our channel */
+ p->mapbase = ioremap_nocache(res->start, resource_size(res));
+ if (p->mapbase == NULL) {
+ pr_err("sh_cmt: failed to remap I/O memory\n");
+ goto err0;
+ }
+
+ /* request irq using setup_irq() (too early for request_irq()) */
+ p->irqaction.name = cfg->name;
+ p->irqaction.handler = sh_cmt_interrupt;
+ p->irqaction.dev_id = p;
+ p->irqaction.flags = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL;
+ p->irqaction.mask = CPU_MASK_NONE;
+ ret = setup_irq(irq, &p->irqaction);
+ if (ret) {
+ pr_err("sh_cmt: failed to request irq %d\n", irq);
+ goto err1;
+ }
+
+ /* get hold of clock */
+ p->clk = clk_get(&p->pdev->dev, cfg->clk);
+ if (IS_ERR(p->clk)) {
+ pr_err("sh_cmt: cannot get clock \"%s\"\n", cfg->clk);
+ ret = PTR_ERR(p->clk);
+ goto err2;
+ }
+
+ if (resource_size(res) == 6) {
+ p->width = 16;
+ p->overflow_bit = 0x80;
+ p->clear_bits = ~0xc0;
+ } else {
+ p->width = 32;
+ p->overflow_bit = 0x8000;
+ p->clear_bits = ~0xc000;
+ }
+
+ return sh_cmt_register(p, cfg->name,
+ cfg->clockevent_rating,
+ cfg->clocksource_rating);
+ err2:
+ free_irq(irq, p);
+ err1:
+ iounmap(p->mapbase);
+ err0:
+ return ret;
+}
+
+static int __devinit sh_cmt_probe(struct platform_device *pdev)
+{
+ struct sh_cmt_priv *p = platform_get_drvdata(pdev);
+ int ret;
+
+ p = kmalloc(sizeof(*p), GFP_KERNEL);
+ if (p == NULL) {
+ dev_err(&pdev->dev, "failed to allocate driver data\n");
+ return -ENOMEM;
+ }
+
+ ret = sh_cmt_setup(p, pdev);
+ if (ret) {
+ kfree(p);
+
+ platform_set_drvdata(pdev, NULL);
+ }
+ return ret;
+}
+
+static int __devexit sh_cmt_remove(struct platform_device *pdev)
+{
+ return -EBUSY; /* cannot unregister clockevent and clocksource */
+}
+
+static struct platform_driver sh_cmt_device_driver = {
+ .probe = sh_cmt_probe,
+ .remove = __devexit_p(sh_cmt_remove),
+ .driver = {
+ .name = "sh_cmt",
+ }
+};
+
+static int __init sh_cmt_init(void)
+{
+ return platform_driver_register(&sh_cmt_device_driver);
+}
+
+static void __exit sh_cmt_exit(void)
+{
+ platform_driver_unregister(&sh_cmt_device_driver);
+}
+
+module_init(sh_cmt_init);
+module_exit(sh_cmt_exit);
+
+MODULE_AUTHOR("Magnus Damm");
+MODULE_DESCRIPTION("SuperH CMT Timer Driver");
+MODULE_LICENSE("GPL v2");
git://ftp.safe.ca / safe / jmp / linux-2.6 / commitdiff