diff options
author | Magnus Damm <damm@igel.co.jp> | 2009-01-22 09:55:59 +0000 |
---|---|---|
committer | Paul Mundt <lethal@linux-sh.org> | 2009-01-29 16:56:32 +0900 |
commit | 3fb1b6ad0679ad671bd496712b2a088550ee86b2 (patch) | |
tree | c8cbdb83a2ee6f3d1b9078d7b87e92e7dc1d9764 | |
parent | 07821d3310996746a2cf1e9c705ffe64223d1112 (diff) | |
download | kernel_samsung_smdk4412-3fb1b6ad0679ad671bd496712b2a088550ee86b2.zip kernel_samsung_smdk4412-3fb1b6ad0679ad671bd496712b2a088550ee86b2.tar.gz kernel_samsung_smdk4412-3fb1b6ad0679ad671bd496712b2a088550ee86b2.tar.bz2 |
sh: CMT clockevent platform driver
SuperH CMT clockevent driver.
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.
This version is lacking clocksource and early platform driver support
for now - this to minimize the amount of dependencies.
Signed-off-by: Magnus Damm <damm@igel.co.jp>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
-rw-r--r-- | arch/sh/Kconfig | 8 | ||||
-rw-r--r-- | drivers/clocksource/Makefile | 1 | ||||
-rw-r--r-- | drivers/clocksource/sh_cmt.c | 615 | ||||
-rw-r--r-- | include/linux/sh_cmt.h | 13 |
4 files changed, 637 insertions, 0 deletions
diff --git a/arch/sh/Kconfig b/arch/sh/Kconfig index ebabe51..5407e12 100644 --- a/arch/sh/Kconfig +++ b/arch/sh/Kconfig @@ -397,6 +397,14 @@ source "arch/sh/boards/Kconfig" menu "Timer and clock configuration" +config SH_TIMER_CMT + def_bool n + prompt "CMT support" + select GENERIC_TIME + select GENERIC_CLOCKEVENTS + help + This enables build of the CMT system timer driver. + config SH_TMU def_bool y prompt "TMU timer support" diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile index 1525882..1efb287 100644 --- a/drivers/clocksource/Makefile +++ b/drivers/clocksource/Makefile @@ -2,3 +2,4 @@ obj-$(CONFIG_ATMEL_TCB_CLKSRC) += tcb_clksrc.o obj-$(CONFIG_X86_CYCLONE_TIMER) += cyclone.o obj-$(CONFIG_X86_PM_TIMER) += acpi_pm.o obj-$(CONFIG_SCx200HR_TIMER) += scx200_hrt.o +obj-$(CONFIG_SH_TIMER_CMT) += sh_cmt.o diff --git a/drivers/clocksource/sh_cmt.c b/drivers/clocksource/sh_cmt.c new file mode 100644 index 0000000..7783b42 --- /dev/null +++ b/drivers/clocksource/sh_cmt.c @@ -0,0 +1,615 @@ +/* + * 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"); diff --git a/include/linux/sh_cmt.h b/include/linux/sh_cmt.h new file mode 100644 index 0000000..68cacde --- /dev/null +++ b/include/linux/sh_cmt.h @@ -0,0 +1,13 @@ +#ifndef __SH_CMT_H__ +#define __SH_CMT_H__ + +struct sh_cmt_config { + char *name; + unsigned long channel_offset; + int timer_bit; + char *clk; + unsigned long clockevent_rating; + unsigned long clocksource_rating; +}; + +#endif /* __SH_CMT_H__ */ |