clocksource: SuperH TMU Timer driver
This patch adds a TMU driver for the SuperH architecture.
The TMU driver is a platform driver with early platform
support to allow using a TMU channel as clockevent or
clocksource during system bootup or later.
Clocksource or clockevent can be selected.
Both periodic and oneshot clockevents are supported.
Signed-off-by: Magnus Damm <damm@igel.co.jp>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
diff --git a/arch/sh/Kconfig b/arch/sh/Kconfig
index bda3dc1..1f74737 100644
--- a/arch/sh/Kconfig
+++ b/arch/sh/Kconfig
@@ -116,6 +116,9 @@
config SYS_SUPPORTS_MTU2
bool
+config SYS_SUPPORTS_TMU
+ bool
+
config STACKTRACE_SUPPORT
def_bool y
@@ -470,6 +473,15 @@
help
This enables the use of the TMU as the system timer.
+config SH_TIMER_TMU
+ bool "TMU timer driver"
+ depends on !SH_TMU && SYS_SUPPORTS_TMU
+ default y
+ select GENERIC_TIME
+ select GENERIC_CLOCKEVENTS
+ help
+ This enables the build of the TMU timer driver.
+
config SH_TIMER_CMT
bool "CMT timer driver"
depends on SYS_SUPPORTS_CMT
diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile
index 9785586..eef216f 100644
--- a/drivers/clocksource/Makefile
+++ b/drivers/clocksource/Makefile
@@ -4,3 +4,4 @@
obj-$(CONFIG_SCx200HR_TIMER) += scx200_hrt.o
obj-$(CONFIG_SH_TIMER_CMT) += sh_cmt.o
obj-$(CONFIG_SH_TIMER_MTU2) += sh_mtu2.o
+obj-$(CONFIG_SH_TIMER_TMU) += sh_tmu.o
diff --git a/drivers/clocksource/sh_tmu.c b/drivers/clocksource/sh_tmu.c
new file mode 100644
index 0000000..21bd77a
--- /dev/null
+++ b/drivers/clocksource/sh_tmu.c
@@ -0,0 +1,461 @@
+/*
+ * SuperH Timer Support - TMU
+ *
+ * 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/clocksource.h>
+#include <linux/clockchips.h>
+#include <linux/sh_tmu.h>
+
+struct sh_tmu_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;
+ struct clocksource cs;
+};
+
+static DEFINE_SPINLOCK(sh_tmu_lock);
+
+#define TSTR -1 /* shared register */
+#define TCOR 0 /* channel register */
+#define TCNT 1 /* channel register */
+#define TCR 2 /* channel register */
+
+static inline unsigned long sh_tmu_read(struct sh_tmu_priv *p, int reg_nr)
+{
+ struct sh_tmu_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 = reg_nr << 2;
+
+ if (reg_nr == TCR)
+ return ioread16(base + offs);
+ else
+ return ioread32(base + offs);
+}
+
+static inline void sh_tmu_write(struct sh_tmu_priv *p, int reg_nr,
+ unsigned long value)
+{
+ struct sh_tmu_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 = reg_nr << 2;
+
+ if (reg_nr == TCR)
+ iowrite16(value, base + offs);
+ else
+ iowrite32(value, base + offs);
+}
+
+static void sh_tmu_start_stop_ch(struct sh_tmu_priv *p, int start)
+{
+ struct sh_tmu_config *cfg = p->pdev->dev.platform_data;
+ unsigned long flags, value;
+
+ /* start stop register shared by multiple timer channels */
+ spin_lock_irqsave(&sh_tmu_lock, flags);
+ value = sh_tmu_read(p, TSTR);
+
+ if (start)
+ value |= 1 << cfg->timer_bit;
+ else
+ value &= ~(1 << cfg->timer_bit);
+
+ sh_tmu_write(p, TSTR, value);
+ spin_unlock_irqrestore(&sh_tmu_lock, flags);
+}
+
+static int sh_tmu_enable(struct sh_tmu_priv *p)
+{
+ struct sh_tmu_config *cfg = p->pdev->dev.platform_data;
+ int ret;
+
+ /* enable clock */
+ ret = clk_enable(p->clk);
+ if (ret) {
+ pr_err("sh_tmu: cannot enable clock \"%s\"\n", cfg->clk);
+ return ret;
+ }
+
+ /* make sure channel is disabled */
+ sh_tmu_start_stop_ch(p, 0);
+
+ /* maximum timeout */
+ sh_tmu_write(p, TCOR, 0xffffffff);
+ sh_tmu_write(p, TCNT, 0xffffffff);
+
+ /* configure channel to parent clock / 4, irq off */
+ p->rate = clk_get_rate(p->clk) / 4;
+ sh_tmu_write(p, TCR, 0x0000);
+
+ /* enable channel */
+ sh_tmu_start_stop_ch(p, 1);
+
+ return 0;
+}
+
+static void sh_tmu_disable(struct sh_tmu_priv *p)
+{
+ /* disable channel */
+ sh_tmu_start_stop_ch(p, 0);
+
+ /* stop clock */
+ clk_disable(p->clk);
+}
+
+static void sh_tmu_set_next(struct sh_tmu_priv *p, unsigned long delta,
+ int periodic)
+{
+ /* stop timer */
+ sh_tmu_start_stop_ch(p, 0);
+
+ /* acknowledge interrupt */
+ sh_tmu_read(p, TCR);
+
+ /* enable interrupt */
+ sh_tmu_write(p, TCR, 0x0020);
+
+ /* reload delta value in case of periodic timer */
+ if (periodic)
+ sh_tmu_write(p, TCOR, delta);
+ else
+ sh_tmu_write(p, TCOR, 0);
+
+ sh_tmu_write(p, TCNT, delta);
+
+ /* start timer */
+ sh_tmu_start_stop_ch(p, 1);
+}
+
+static irqreturn_t sh_tmu_interrupt(int irq, void *dev_id)
+{
+ struct sh_tmu_priv *p = dev_id;
+
+ /* disable or acknowledge interrupt */
+ if (p->ced.mode == CLOCK_EVT_MODE_ONESHOT)
+ sh_tmu_write(p, TCR, 0x0000);
+ else
+ sh_tmu_write(p, TCR, 0x0020);
+
+ /* notify clockevent layer */
+ p->ced.event_handler(&p->ced);
+ return IRQ_HANDLED;
+}
+
+static struct sh_tmu_priv *cs_to_sh_tmu(struct clocksource *cs)
+{
+ return container_of(cs, struct sh_tmu_priv, cs);
+}
+
+static cycle_t sh_tmu_clocksource_read(struct clocksource *cs)
+{
+ struct sh_tmu_priv *p = cs_to_sh_tmu(cs);
+
+ return sh_tmu_read(p, TCNT) ^ 0xffffffff;
+}
+
+static int sh_tmu_clocksource_enable(struct clocksource *cs)
+{
+ struct sh_tmu_priv *p = cs_to_sh_tmu(cs);
+ int ret;
+
+ ret = sh_tmu_enable(p);
+ if (ret)
+ return ret;
+
+ /* TODO: calculate good shift from rate and counter bit width */
+ cs->shift = 10;
+ cs->mult = clocksource_hz2mult(p->rate, cs->shift);
+ return 0;
+}
+
+static void sh_tmu_clocksource_disable(struct clocksource *cs)
+{
+ sh_tmu_disable(cs_to_sh_tmu(cs));
+}
+
+static int sh_tmu_register_clocksource(struct sh_tmu_priv *p,
+ char *name, unsigned long rating)
+{
+ struct clocksource *cs = &p->cs;
+
+ cs->name = name;
+ cs->rating = rating;
+ cs->read = sh_tmu_clocksource_read;
+ cs->enable = sh_tmu_clocksource_enable;
+ cs->disable = sh_tmu_clocksource_disable;
+ cs->mask = CLOCKSOURCE_MASK(32);
+ cs->flags = CLOCK_SOURCE_IS_CONTINUOUS;
+ pr_info("sh_tmu: %s used as clock source\n", cs->name);
+ clocksource_register(cs);
+ return 0;
+}
+
+static struct sh_tmu_priv *ced_to_sh_tmu(struct clock_event_device *ced)
+{
+ return container_of(ced, struct sh_tmu_priv, ced);
+}
+
+static void sh_tmu_clock_event_start(struct sh_tmu_priv *p, int periodic)
+{
+ struct clock_event_device *ced = &p->ced;
+
+ sh_tmu_enable(p);
+
+ /* 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(0xffffffff, ced);
+ ced->min_delta_ns = 5000;
+
+ if (periodic) {
+ p->periodic = (p->rate + HZ/2) / HZ;
+ sh_tmu_set_next(p, p->periodic, 1);
+ }
+}
+
+static void sh_tmu_clock_event_mode(enum clock_event_mode mode,
+ struct clock_event_device *ced)
+{
+ struct sh_tmu_priv *p = ced_to_sh_tmu(ced);
+ int disabled = 0;
+
+ /* deal with old setting first */
+ switch (ced->mode) {
+ case CLOCK_EVT_MODE_PERIODIC:
+ case CLOCK_EVT_MODE_ONESHOT:
+ sh_tmu_disable(p);
+ disabled = 1;
+ break;
+ default:
+ break;
+ }
+
+ switch (mode) {
+ case CLOCK_EVT_MODE_PERIODIC:
+ pr_info("sh_tmu: %s used for periodic clock events\n",
+ ced->name);
+ sh_tmu_clock_event_start(p, 1);
+ break;
+ case CLOCK_EVT_MODE_ONESHOT:
+ pr_info("sh_tmu: %s used for oneshot clock events\n",
+ ced->name);
+ sh_tmu_clock_event_start(p, 0);
+ break;
+ case CLOCK_EVT_MODE_UNUSED:
+ if (!disabled)
+ sh_tmu_disable(p);
+ break;
+ case CLOCK_EVT_MODE_SHUTDOWN:
+ default:
+ break;
+ }
+}
+
+static int sh_tmu_clock_event_next(unsigned long delta,
+ struct clock_event_device *ced)
+{
+ struct sh_tmu_priv *p = ced_to_sh_tmu(ced);
+
+ BUG_ON(ced->mode != CLOCK_EVT_MODE_ONESHOT);
+
+ /* program new delta value */
+ sh_tmu_set_next(p, delta, 0);
+ return 0;
+}
+
+static void sh_tmu_register_clockevent(struct sh_tmu_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->features |= CLOCK_EVT_FEAT_ONESHOT;
+ ced->rating = rating;
+ ced->cpumask = cpumask_of(0);
+ ced->set_next_event = sh_tmu_clock_event_next;
+ ced->set_mode = sh_tmu_clock_event_mode;
+
+ ret = setup_irq(p->irqaction.irq, &p->irqaction);
+ if (ret) {
+ pr_err("sh_tmu: failed to request irq %d\n",
+ p->irqaction.irq);
+ return;
+ }
+
+ pr_info("sh_tmu: %s used for clock events\n", ced->name);
+ clockevents_register_device(ced);
+}
+
+static int sh_tmu_register(struct sh_tmu_priv *p, char *name,
+ unsigned long clockevent_rating,
+ unsigned long clocksource_rating)
+{
+ if (clockevent_rating)
+ sh_tmu_register_clockevent(p, name, clockevent_rating);
+ else if (clocksource_rating)
+ sh_tmu_register_clocksource(p, name, clocksource_rating);
+
+ return 0;
+}
+
+static int sh_tmu_setup(struct sh_tmu_priv *p, struct platform_device *pdev)
+{
+ struct sh_tmu_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_tmu: failed to remap I/O memory\n");
+ goto err0;
+ }
+
+ /* setup data for setup_irq() (too early for request_irq()) */
+ p->irqaction.name = cfg->name;
+ p->irqaction.handler = sh_tmu_interrupt;
+ p->irqaction.dev_id = p;
+ p->irqaction.irq = irq;
+ p->irqaction.flags = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL;
+ p->irqaction.mask = CPU_MASK_NONE;
+
+ /* get hold of clock */
+ p->clk = clk_get(&p->pdev->dev, cfg->clk);
+ if (IS_ERR(p->clk)) {
+ pr_err("sh_tmu: cannot get clock \"%s\"\n", cfg->clk);
+ ret = PTR_ERR(p->clk);
+ goto err1;
+ }
+
+ return sh_tmu_register(p, cfg->name,
+ cfg->clockevent_rating,
+ cfg->clocksource_rating);
+ err1:
+ iounmap(p->mapbase);
+ err0:
+ return ret;
+}
+
+static int __devinit sh_tmu_probe(struct platform_device *pdev)
+{
+ struct sh_tmu_priv *p = platform_get_drvdata(pdev);
+ struct sh_tmu_config *cfg = pdev->dev.platform_data;
+ int ret;
+
+ if (p) {
+ pr_info("sh_tmu: %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_tmu_setup(p, pdev);
+ if (ret) {
+ kfree(p);
+ platform_set_drvdata(pdev, NULL);
+ }
+ return ret;
+}
+
+static int __devexit sh_tmu_remove(struct platform_device *pdev)
+{
+ return -EBUSY; /* cannot unregister clockevent and clocksource */
+}
+
+static struct platform_driver sh_tmu_device_driver = {
+ .probe = sh_tmu_probe,
+ .remove = __devexit_p(sh_tmu_remove),
+ .driver = {
+ .name = "sh_tmu",
+ }
+};
+
+static int __init sh_tmu_init(void)
+{
+ return platform_driver_register(&sh_tmu_device_driver);
+}
+
+static void __exit sh_tmu_exit(void)
+{
+ platform_driver_unregister(&sh_tmu_device_driver);
+}
+
+early_platform_init("earlytimer", &sh_tmu_device_driver);
+module_init(sh_tmu_init);
+module_exit(sh_tmu_exit);
+
+MODULE_AUTHOR("Magnus Damm");
+MODULE_DESCRIPTION("SuperH TMU Timer Driver");
+MODULE_LICENSE("GPL v2");
diff --git a/include/linux/sh_tmu.h b/include/linux/sh_tmu.h
new file mode 100644
index 0000000..b1195e8
--- /dev/null
+++ b/include/linux/sh_tmu.h
@@ -0,0 +1,13 @@
+#ifndef __SH_TMU_H__
+#define __SH_TMU_H__
+
+struct sh_tmu_config {
+ char *name;
+ unsigned long channel_offset;
+ int timer_bit;
+ char *clk;
+ unsigned long clockevent_rating;
+ unsigned long clocksource_rating;
+};
+
+#endif /* __SH_TMU_H__ */