- 根目录:
- drivers
- clocksource
- sh_mtu2.c
/*
* SuperH Timer Support - MTU2
*
* Copyright (C) 2009 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/delay.h>
#include <linux/io.h>
#include <linux/clk.h>
#include <linux/irq.h>
#include <linux/err.h>
#include <linux/clockchips.h>
#include <linux/sh_timer.h>
#include <linux/slab.h>
#include <linux/module.h>
struct sh_mtu2_priv {
void __iomem *mapbase;
struct clk *clk;
struct irqaction irqaction;
struct platform_device *pdev;
unsigned long rate;
unsigned long periodic;
struct clock_event_device ced;
};
static DEFINE_SPINLOCK(sh_mtu2_lock);
#define TSTR -1 /* shared register */
#define TCR 0 /* channel register */
#define TMDR 1 /* channel register */
#define TIOR 2 /* channel register */
#define TIER 3 /* channel register */
#define TSR 4 /* channel register */
#define TCNT 5 /* channel register */
#define TGR 6 /* channel register */
static unsigned long mtu2_reg_offs[] = {
[TCR] = 0,
[TMDR] = 1,
[TIOR] = 2,
[TIER] = 4,
[TSR] = 5,
[TCNT] = 6,
[TGR] = 8,
};
static inline unsigned long sh_mtu2_read(struct sh_mtu2_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 == TSTR)
return ioread8(base + cfg->channel_offset);
offs = mtu2_reg_offs[reg_nr];
if ((reg_nr == TCNT) || (reg_nr == TGR))
return ioread16(base + offs);
else
return ioread8(base + offs);
}
static inline void sh_mtu2_write(struct sh_mtu2_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 == TSTR) {
iowrite8(value, base + cfg->channel_offset);
return;
}
offs = mtu2_reg_offs[reg_nr];
if ((reg_nr == TCNT) || (reg_nr == TGR))
iowrite16(value, base + offs);
else
iowrite8(value, base + offs);
}
static void sh_mtu2_start_stop_ch(struct sh_mtu2_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_mtu2_lock, flags);
value = sh_mtu2_read(p, TSTR);
if (start)
value |= 1 << cfg->timer_bit;
else
value &= ~(1 << cfg->timer_bit);
sh_mtu2_write(p, TSTR, value);
spin_unlock_irqrestore(&sh_mtu2_lock, flags);
}
static int sh_mtu2_enable(struct sh_mtu2_priv *p)
{
int ret;
/* enable clock */
ret = clk_enable(p->clk);
if (ret) {
dev_err(&p->pdev->dev, "cannot enable clock\n");
return ret;
}
/* make sure channel is disabled */
sh_mtu2_start_stop_ch(p, 0);
p->rate = clk_get_rate(p->clk) / 64;
p->periodic = (p->rate + HZ/2) / HZ;
/* "Periodic Counter Operation" */
sh_mtu2_write(p, TCR, 0x23); /* TGRA clear, divide clock by 64 */
sh_mtu2_write(p, TIOR, 0);
sh_mtu2_write(p, TGR, p->periodic);
sh_mtu2_write(p, TCNT, 0);
sh_mtu2_write(p, TMDR, 0);
sh_mtu2_write(p, TIER, 0x01);
/* enable channel */
sh_mtu2_start_stop_ch(p, 1);
return 0;
}
static void sh_mtu2_disable(struct sh_mtu2_priv *p)
{
/* disable channel */
sh_mtu2_start_stop_ch(p, 0);
/* stop clock */
clk_disable(p->clk);
}
static irqreturn_t sh_mtu2_interrupt(int irq, void *dev_id)
{
struct sh_mtu2_priv *p = dev_id;
/* acknowledge interrupt */
sh_mtu2_read(p, TSR);
sh_mtu2_write(p, TSR, 0xfe);
/* notify clockevent layer */
p->ced.event_handler(&p->ced);
return IRQ_HANDLED;
}
static struct sh_mtu2_priv *ced_to_sh_mtu2(struct clock_event_device *ced)
{
return container_of(ced, struct sh_mtu2_priv, ced);
}
static void sh_mtu2_clock_event_mode(enum clock_event_mode mode,
struct clock_event_device *ced)
{
struct sh_mtu2_priv *p = ced_to_sh_mtu2(ced);
int disabled = 0;
/* deal with old setting first */
switch (ced->mode) {
case CLOCK_EVT_MODE_PERIODIC:
sh_mtu2_disable(p);
disabled = 1;
break;
default:
break;
}
switch (mode) {
case CLOCK_EVT_MODE_PERIODIC:
dev_info(&p->pdev->dev, "used for periodic clock events\n");
sh_mtu2_enable(p);
break;
case CLOCK_EVT_MODE_UNUSED:
if (!disabled)
sh_mtu2_disable(p);
break;
case CLOCK_EVT_MODE_SHUTDOWN:
default:
break;
}
}
static void sh_mtu2_register_clockevent(struct sh_mtu2_priv *p,
char *name, unsigned long rating)
{
struct clock_event_device *ced = &p->ced;
int ret;
memset(ced, 0, sizeof(*ced));
ced->name = name;
ced->features = CLOCK_EVT_FEAT_PERIODIC;
ced->rating = rating;
ced->cpumask = cpumask_of(0);
ced->set_mode = sh_mtu2_clock_event_mode;
dev_info(&p->pdev->dev, "used for clock events\n");
clockevents_register_device(ced);
ret = setup_irq(p->irqaction.irq, &p->irqaction);
if (ret) {
dev_err(&p->pdev->dev, "failed to request irq %d\n",
p->irqaction.irq);
return;
}
}
static int sh_mtu2_register(struct sh_mtu2_priv *p, char *name,
unsigned long clockevent_rating)
{
if (clockevent_rating)
sh_mtu2_register_clockevent(p, name, clockevent_rating);
return 0;
}
static int sh_mtu2_setup(struct sh_mtu2_priv *p, struct platform_device *pdev)
{
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, 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) {
dev_err(&p->pdev->dev, "failed to remap I/O memory\n");
goto err0;
}
/* setup data for setup_irq() (too early for request_irq()) */
p->irqaction.name = dev_name(&p->pdev->dev);
p->irqaction.handler = sh_mtu2_interrupt;
p->irqaction.dev_id = p;
p->irqaction.irq = irq;
p->irqaction.flags = IRQF_DISABLED | IRQF_TIMER | \
IRQF_IRQPOLL | IRQF_NOBALANCING;
/* get hold of clock */
p->clk = clk_get(&p->pdev->dev, "mtu2_fck");
if (IS_ERR(p->clk)) {
dev_err(&p->pdev->dev, "cannot get clock\n");
ret = PTR_ERR(p->clk);
goto err1;
}
return sh_mtu2_register(p, (char *)dev_name(&p->pdev->dev),
cfg->clockevent_rating);
err1:
iounmap(p->mapbase);
err0:
return ret;
}
static int __devinit sh_mtu2_probe(struct platform_device *pdev)
{
struct sh_mtu2_priv *p = platform_get_drvdata(pdev);
int ret;
if (p) {
dev_info(&pdev->dev, "kept as earlytimer\n");
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_mtu2_setup(p, pdev);
if (ret) {
kfree(p);
platform_set_drvdata(pdev, NULL);
}
return ret;
}
static int __devexit sh_mtu2_remove(struct platform_device *pdev)
{
return -EBUSY; /* cannot unregister clockevent */
}
static struct platform_driver sh_mtu2_device_driver = {
.probe = sh_mtu2_probe,
.remove = __devexit_p(sh_mtu2_remove),
.driver = {
.name = "sh_mtu2",
}
};
static int __init sh_mtu2_init(void)
{
return platform_driver_register(&sh_mtu2_device_driver);
}
static void __exit sh_mtu2_exit(void)
{
platform_driver_unregister(&sh_mtu2_device_driver);
}
early_platform_init("earlytimer", &sh_mtu2_device_driver);
module_init(sh_mtu2_init);
module_exit(sh_mtu2_exit);
MODULE_AUTHOR("Magnus Damm");
MODULE_DESCRIPTION("SuperH MTU2 Timer Driver");
MODULE_LICENSE("GPL v2");