linux/drivers/clocksource/sh_cmt.c

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/*
* 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/clocksource.h>
#include <linux/clockchips.h>
#include <linux/sh_timer.h>
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-24 16:04:11 +08:00
#include <linux/slab.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;
int o1, o2;
o1 = sh_cmt_read(p, CMCSR) & p->overflow_bit;
/* Make sure the timer value is stable. Stolen from acpi_pm.c */
do {
o2 = o1;
v1 = sh_cmt_read(p, CMCNT);
v2 = sh_cmt_read(p, CMCNT);
v3 = sh_cmt_read(p, CMCNT);
o1 = sh_cmt_read(p, CMCSR) & p->overflow_bit;
} while (unlikely((o1 != o2) || (v1 > v2 && v1 < v3)
|| (v2 > v3 && v2 < v1) || (v3 > v1 && v3 < v2)));
*has_wrapped = o1;
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;
}
/* make sure channel is disabled */
sh_cmt_start_stop_ch(p, 0);
/* configure channel, periodic mode and maximum timeout */
if (p->width == 16) {
*rate = clk_get_rate(p->clk) / 512;
sh_cmt_write(p, CMCSR, 0x43);
} else {
*rate = clk_get_rate(p->clk) / 8;
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);
/* disable interrupts in CMT block */
sh_cmt_write(p, CMCSR, 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 void sh_cmt_clocksource_resume(struct clocksource *cs)
{
sh_cmt_start(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->read = sh_cmt_clocksource_read;
cs->enable = sh_cmt_clocksource_enable;
cs->disable = sh_cmt_clocksource_disable;
cs->suspend = sh_cmt_clocksource_disable;
cs->resume = sh_cmt_clocksource_resume;
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 = 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);
clockevents_register_device(ced);
}
static 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(struct sh_cmt_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) {
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;
/* 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 err1;
}
if (resource_size(res) == 6) {
p->width = 16;
p->overflow_bit = 0x80;
p->clear_bits = ~0x80;
} else {
p->width = 32;
p->overflow_bit = 0x8000;
p->clear_bits = ~0xc000;
}
ret = sh_cmt_register(p, cfg->name,
cfg->clockevent_rating,
cfg->clocksource_rating);
if (ret) {
pr_err("sh_cmt: registration failed\n");
goto err1;
}
ret = setup_irq(irq, &p->irqaction);
if (ret) {
pr_err("sh_cmt: failed to request irq %d\n", irq);
goto err1;
}
return 0;
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);
struct sh_timer_config *cfg = pdev->dev.platform_data;
int ret;
if (p) {
pr_info("sh_cmt: %s kept as earlytimer\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);
}
early_platform_init("earlytimer", &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");