Re: [PATCH 04/05] sh: CMT platform driver using early timer

john stultz
2008-12-10T20:33:43Z

On Thu, 2008-12-11 at 00:13 +0900, Magnus Damm wrote:
> From: Magnus Damm <damm@igel.co.jp>
>
> CMT driver for the SuperH timer base code implementation V4.
> Both 16-bit and 32-bit CMT versions are supported, but only 32-bit
> is tested. This driver contains support for both clockevents and
> clocksources, but no unregistration is supported at this point.
>
> Works fine as clock source and/or event in periodic or oneshot mode.
> Tested on sh7722 and sh7723, but should work with any cpu/architecture.
>
> Signed-off-by: Magnus Damm <damm@igel.co.jp>

Looks good to me. Thanks again for reworking this!

Acked-by: John Stultz <johnstul@us.ibm.com>

> ---
>
> Changes since V3 include:
> - Removed dependency of timer_inc
> - Removed unregistration code
>
> Changes since V2 include:
> - Rewrote driver to platform driver and early timer
> - Only control clocks and hardware registers in disable()/enable()
> - Removed exported struct from sh_timer.c/sh_timer.h
> - sh_timer_early_probe() is used for early timer setup
>
> Changes since V1 include:
> - Reworked private data handling - no more union in sh_timer.h
> - Made spinlock static
> - Use setup_irq() to request early interrupt
> - Removed request_mem_region()/free_mem_region()
> - Removed sysdev code
>
> arch/sh/Kconfig | 7
> drivers/clocksource/Makefile | 1
> drivers/clocksource/sh_cmt.c | 702 ++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 710 insertions(+)
>
> --- 0010/arch/sh/Kconfig
> +++ work/arch/sh/Kconfig 2008-12-10 22:59:45.000000000 +0900
> @@ -403,6 +403,13 @@ config SH_TIMER
> def_bool n
> select GENERIC_CLOCKEVENTS
>
> +config SH_TIMER_CMT
> + def_bool y
> + prompt "CMT timer support"
> + depends on SH_TIMER
> + help
> + This enables build of the CMT system timer driver.
> +
> config SH_TMU
> def_bool y
> prompt "TMU timer support"
> --- 0009/drivers/clocksource/Makefile
> +++ work/drivers/clocksource/Makefile 2008-12-10 22:59:45.000000000 +0900
> @@ -3,3 +3,4 @@ obj-$(CONFIG_X86_CYCLONE_TIMER) += cyclo
> obj-$(CONFIG_X86_PM_TIMER) += acpi_pm.o
> obj-$(CONFIG_SCx200HR_TIMER) += scx200_hrt.o
> obj-$(CONFIG_SH_TIMER) += sh_timer.o
> +obj-$(CONFIG_SH_TIMER_CMT) += sh_cmt.o
> --- /dev/null
> +++ work/drivers/clocksource/sh_cmt.c 2008-12-10 23:01:48.000000000 +0900
> @@ -0,0 +1,702 @@
> +/*
> + * 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/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/sh_timer.h>
> +#include <linux/clocksource.h>
> +#include <linux/clockchips.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;
> + struct clocksource cs;
> + 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_timer_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_timer_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_timer_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_timer_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 *cs_to_sh_cmt(struct clocksource *cs)
> +{
> + return container_of(cs, struct sh_cmt_priv, cs);
> +}
> +
> +static cycle_t sh_cmt_clocksource_read(struct clocksource *cs)
> +{
> + struct sh_cmt_priv *p = cs_to_sh_cmt(cs);
> + unsigned long flags, raw;
> + unsigned long value;
> + int has_wrapped;
> +
> + spin_lock_irqsave(&p->lock, flags);
> + value = p->total_cycles;
> + raw = sh_cmt_get_counter(p, &has_wrapped);
> +
> + if (unlikely(has_wrapped))
> + raw = p->match_value;
> + spin_unlock_irqrestore(&p->lock, flags);
> +
> + return value + raw;
> +}
> +
> +static int sh_cmt_clocksource_enable(struct clocksource *cs)
> +{
> + struct sh_cmt_priv *p = cs_to_sh_cmt(cs);
> + int ret;
> +
> + p->total_cycles = 0;
> +
> + ret = sh_cmt_start(p, FLAG_CLOCKSOURCE);
> + if (ret)
> + return ret;
> +
> + /* TODO: calculate good shift from rate and counter bit width */
> + cs->shift = 0;
> + cs->mult = clocksource_hz2mult(p->rate, cs->shift);
> + return 0;
> +}
> +
> +static void sh_cmt_clocksource_disable(struct clocksource *cs)
> +{
> + sh_cmt_stop(cs_to_sh_cmt(cs), FLAG_CLOCKSOURCE);
> +}
> +
> +static int sh_cmt_register_clocksource(struct sh_cmt_priv *p,
> + char *name, unsigned long rating)
> +{
> + struct clocksource *cs = &p->cs;
> +
> + cs->name = name;
> + cs->rating = rating;
> + cs->read2 = sh_cmt_clocksource_read;
> + cs->enable = sh_cmt_clocksource_enable;
> + cs->disable = sh_cmt_clocksource_disable;
> + cs->mask = CLOCKSOURCE_MASK(sizeof(unsigned long) * 8);
> + cs->flags = CLOCK_SOURCE_IS_CONTINUOUS;
> + pr_info("sh_cmt: %s used as clock source\n", cs->name);
> + clocksource_register(cs);
> + return 0;
> +}
> +
> +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 = CPU_MASK_CPU0;
> + 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);
> +
> + if (clocksource_rating)
> + sh_cmt_register_clocksource(p, name, clocksource_rating);
> +
> + return 0;
> +}
> +
> +static int sh_cmt_setup(void *priv, struct platform_device *pdev)
> +{
> + struct sh_cmt_priv *p = priv;
> + struct sh_timer_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, priv);
> +
> + 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;
> +}
> +
> +#ifndef MODULE
> +/* early timer interface, used before platform devices are available */
> +static struct sh_timer_early sh_cmt = {
> + .priv_size = sizeof(struct sh_cmt_priv),
> + .setup = sh_cmt_setup,
> +};
> +
> +struct sh_timer_early *sh_timer_early_probe(struct platform_device *pdev)
> +{
> + if (!strcmp(pdev->name, "sh_cmt"))
> + return &sh_cmt;
> +
> + return NULL;
> +}
> +#endif
> +
> +static int __devinit sh_cmt_probe(struct platform_device *pdev)
> +{
> + struct sh_cmt_priv *p = platform_get_drvdata(pdev);
> + struct sh_timer_config *cfg = pdev->dev.platform_data;
> + int ret;
> +
> + if (p) {
> + pr_info("sh_cmt: %s kept as early timer\n", cfg->name);
> + return 0;
> + }
> +
> + 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");