| From c97faaf620983062ebff15fd4db3f341a8e224b2 Mon Sep 17 00:00:00 2001 |
| From: Magnus Damm <damm@opensource.se> |
| Date: Wed, 9 May 2012 23:39:42 +0900 |
| Subject: clocksource: em_sti: Emma Mobile STI driver V2 |
| |
| This is V2 of the Emma Mobile STI timer driver. |
| |
| The STI hardware is based on a single 48-bit 32kHz |
| counter that together with two individual compare |
| registers can generate interrupts. There are no |
| timer operating modes selectable which means that |
| the timer can not clear on match. |
| |
| This driver is providing clocksource support for the |
| 48-bit counter. Clockevents are also supported using |
| the same timer in periodic or oneshot modes. |
| |
| Signed-off-by: Magnus Damm <damm@opensource.se> |
| Signed-off-by: Simon Horman <horms@verge.net.au> |
| |
| Conflicts: |
| drivers/clocksource/Makefile |
| --- |
| arch/arm/mach-shmobile/Kconfig | 6 + |
| drivers/clocksource/Makefile | 1 + |
| drivers/clocksource/em_sti.c | 418 ++++++++++++++++++++++++++++++++++++++++ |
| 3 files changed, 425 insertions(+) |
| create mode 100644 drivers/clocksource/em_sti.c |
| |
| diff --git a/arch/arm/mach-shmobile/Kconfig b/arch/arm/mach-shmobile/Kconfig |
| index 9020c1b..1e7656a 100644 |
| --- a/arch/arm/mach-shmobile/Kconfig |
| +++ b/arch/arm/mach-shmobile/Kconfig |
| @@ -147,6 +147,12 @@ config SH_TIMER_TMU |
| help |
| This enables build of the TMU timer driver. |
| |
| +config EM_TIMER_STI |
| + bool "STI timer driver" |
| + default y |
| + help |
| + This enables build of the STI timer driver. |
| + |
| endmenu |
| |
| config SH_CLK_CPG |
| diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile |
| index b995942..59eb37d 100644 |
| --- a/drivers/clocksource/Makefile |
| +++ b/drivers/clocksource/Makefile |
| @@ -6,5 +6,6 @@ obj-$(CONFIG_CS5535_CLOCK_EVENT_SRC) += cs5535-clockevt.o |
| obj-$(CONFIG_SH_TIMER_CMT) += sh_cmt.o |
| obj-$(CONFIG_SH_TIMER_MTU2) += sh_mtu2.o |
| obj-$(CONFIG_SH_TIMER_TMU) += sh_tmu.o |
| +obj-$(CONFIG_EM_TIMER_STI) += em_sti.o |
| obj-$(CONFIG_CLKSRC_I8253) += i8253.o |
| obj-$(CONFIG_CLKSRC_MMIO) += mmio.o |
| diff --git a/drivers/clocksource/em_sti.c b/drivers/clocksource/em_sti.c |
| new file mode 100644 |
| index 0000000..e8fc46d |
| --- /dev/null |
| +++ b/drivers/clocksource/em_sti.c |
| @@ -0,0 +1,418 @@ |
| +/* |
| + * Emma Mobile Timer Support - STI |
| + * |
| + * Copyright (C) 2012 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/delay.h> |
| +#include <linux/clocksource.h> |
| +#include <linux/clockchips.h> |
| +#include <linux/slab.h> |
| +#include <linux/module.h> |
| + |
| +enum { USER_CLOCKSOURCE, USER_CLOCKEVENT, USER_NR }; |
| + |
| +struct em_sti_priv { |
| + void __iomem *base; |
| + struct clk *clk; |
| + struct platform_device *pdev; |
| + unsigned int active[USER_NR]; |
| + unsigned long rate; |
| + unsigned long delta; |
| + cycle_t next; |
| + spinlock_t lock; |
| + struct clock_event_device ced; |
| + struct clocksource cs; |
| +}; |
| + |
| +#define STI_CONTROL 0x00 |
| +#define STI_COMPA_H 0x10 |
| +#define STI_COMPA_L 0x14 |
| +#define STI_COMPB_H 0x18 |
| +#define STI_COMPB_L 0x1c |
| +#define STI_COUNT_H 0x20 |
| +#define STI_COUNT_L 0x24 |
| +#define STI_COUNT_RAW_H 0x28 |
| +#define STI_COUNT_RAW_L 0x2c |
| +#define STI_SET_H 0x30 |
| +#define STI_SET_L 0x34 |
| +#define STI_INTSTATUS 0x40 |
| +#define STI_INTRAWSTATUS 0x44 |
| +#define STI_INTENSET 0x48 |
| +#define STI_INTENCLR 0x4c |
| +#define STI_INTFFCLR 0x50 |
| + |
| +static inline unsigned long em_sti_read(struct em_sti_priv *p, int offs) |
| +{ |
| + return ioread32(p->base + offs); |
| +} |
| + |
| +static inline void em_sti_write(struct em_sti_priv *p, int offs, |
| + unsigned long value) |
| +{ |
| + iowrite32(value, p->base + offs); |
| +} |
| + |
| +static int em_sti_enable(struct em_sti_priv *p) |
| +{ |
| + int ret; |
| + |
| + /* enable clock */ |
| + ret = clk_enable(p->clk); |
| + if (ret) { |
| + dev_err(&p->pdev->dev, "cannot enable clock\n"); |
| + return ret; |
| + } |
| + |
| + /* configure channel, periodic mode and maximum timeout */ |
| + p->rate = clk_get_rate(p->clk); |
| + |
| + /* reset the counter */ |
| + em_sti_write(p, STI_SET_H, 0x40000000); |
| + em_sti_write(p, STI_SET_L, 0x00000000); |
| + |
| + /* mask and clear pending interrupts */ |
| + em_sti_write(p, STI_INTENCLR, 3); |
| + em_sti_write(p, STI_INTFFCLR, 3); |
| + |
| + /* enable updates of counter registers */ |
| + em_sti_write(p, STI_CONTROL, 1); |
| + |
| + return 0; |
| +} |
| + |
| +static void em_sti_disable(struct em_sti_priv *p) |
| +{ |
| + /* mask interrupts */ |
| + em_sti_write(p, STI_INTENCLR, 3); |
| + |
| + /* stop clock */ |
| + clk_disable(p->clk); |
| +} |
| + |
| +static cycle_t em_sti_count(struct em_sti_priv *p) |
| +{ |
| + cycle_t ticks; |
| + unsigned long flags; |
| + |
| + /* the STI hardware buffers the 48-bit count, but to |
| + * break it out into two 32-bit access the registers |
| + * must be accessed in a certain order. |
| + * Always read STI_COUNT_H before STI_COUNT_L. |
| + */ |
| + spin_lock_irqsave(&p->lock, flags); |
| + ticks = (cycle_t)(em_sti_read(p, STI_COUNT_H) & 0xffff) << 32; |
| + ticks |= em_sti_read(p, STI_COUNT_L); |
| + spin_unlock_irqrestore(&p->lock, flags); |
| + |
| + return ticks; |
| +} |
| + |
| +static void em_sti_update(struct em_sti_priv *p) |
| +{ |
| + unsigned long flags; |
| + |
| + spin_lock_irqsave(&p->lock, flags); |
| + |
| + /* update our cached counter */ |
| + p->next += p->delta; |
| + |
| + /* mask compare A interrupt */ |
| + em_sti_write(p, STI_INTENCLR, 1); |
| + |
| + /* update compare A value */ |
| + em_sti_write(p, STI_COMPA_H, p->next >> 32); |
| + em_sti_write(p, STI_COMPA_L, p->next & 0xffffffff); |
| + |
| + /* clear compare A interrupt source */ |
| + em_sti_write(p, STI_INTFFCLR, 1); |
| + |
| + /* unmask compare A interrupt */ |
| + em_sti_write(p, STI_INTENSET, 1); |
| + |
| + spin_unlock_irqrestore(&p->lock, flags); |
| +} |
| + |
| +static irqreturn_t em_sti_interrupt(int irq, void *dev_id) |
| +{ |
| + struct em_sti_priv *p = dev_id; |
| + |
| + /* Always regprogram timer compare A */ |
| + if (p->ced.mode == CLOCK_EVT_MODE_PERIODIC) |
| + em_sti_update(p); |
| + |
| + p->ced.event_handler(&p->ced); |
| + return IRQ_HANDLED; |
| +} |
| + |
| +static int em_sti_start(struct em_sti_priv *p, unsigned int user) |
| +{ |
| + unsigned long flags; |
| + int used_before; |
| + int ret = 0; |
| + |
| + spin_lock_irqsave(&p->lock, flags); |
| + used_before = p->active[USER_CLOCKSOURCE] | p->active[USER_CLOCKEVENT]; |
| + if (!used_before) |
| + ret = em_sti_enable(p); |
| + |
| + if (!ret) |
| + p->active[user] = 1; |
| + spin_unlock_irqrestore(&p->lock, flags); |
| + |
| + return ret; |
| +} |
| + |
| +static void em_sti_stop(struct em_sti_priv *p, unsigned int user) |
| +{ |
| + unsigned long flags; |
| + int used_before, used_after; |
| + |
| + spin_lock_irqsave(&p->lock, flags); |
| + used_before = p->active[USER_CLOCKSOURCE] | p->active[USER_CLOCKEVENT]; |
| + p->active[user] = 0; |
| + used_after = p->active[USER_CLOCKSOURCE] | p->active[USER_CLOCKEVENT]; |
| + |
| + if (used_before && !used_after) |
| + em_sti_disable(p); |
| + spin_unlock_irqrestore(&p->lock, flags); |
| +} |
| + |
| +static struct em_sti_priv *cs_to_em_sti(struct clocksource *cs) |
| +{ |
| + return container_of(cs, struct em_sti_priv, cs); |
| +} |
| + |
| +static cycle_t em_sti_clocksource_read(struct clocksource *cs) |
| +{ |
| + return em_sti_count(cs_to_em_sti(cs)); |
| +} |
| + |
| +static int em_sti_clocksource_enable(struct clocksource *cs) |
| +{ |
| + int ret; |
| + struct em_sti_priv *p = cs_to_em_sti(cs); |
| + |
| + ret = em_sti_start(p, USER_CLOCKSOURCE); |
| + if (!ret) |
| + __clocksource_updatefreq_hz(cs, p->rate); |
| + return ret; |
| +} |
| + |
| +static void em_sti_clocksource_disable(struct clocksource *cs) |
| +{ |
| + em_sti_stop(cs_to_em_sti(cs), USER_CLOCKSOURCE); |
| +} |
| + |
| +static void em_sti_clocksource_resume(struct clocksource *cs) |
| +{ |
| + em_sti_clocksource_enable(cs); |
| +} |
| + |
| +static int em_sti_register_clocksource(struct em_sti_priv *p) |
| +{ |
| + struct clocksource *cs = &p->cs; |
| + |
| + memset(cs, 0, sizeof(*cs)); |
| + cs->name = dev_name(&p->pdev->dev); |
| + cs->rating = 200; |
| + cs->read = em_sti_clocksource_read; |
| + cs->enable = em_sti_clocksource_enable; |
| + cs->disable = em_sti_clocksource_disable; |
| + cs->suspend = em_sti_clocksource_disable; |
| + cs->resume = em_sti_clocksource_resume; |
| + cs->mask = CLOCKSOURCE_MASK(48); |
| + cs->flags = CLOCK_SOURCE_IS_CONTINUOUS; |
| + |
| + dev_info(&p->pdev->dev, "used as clock source\n"); |
| + |
| + /* Register with dummy 1 Hz value, gets updated in ->enable() */ |
| + clocksource_register_hz(cs, 1); |
| + return 0; |
| +} |
| + |
| +static struct em_sti_priv *ced_to_em_sti(struct clock_event_device *ced) |
| +{ |
| + return container_of(ced, struct em_sti_priv, ced); |
| +} |
| + |
| +static void em_sti_clock_event_mode(enum clock_event_mode mode, |
| + struct clock_event_device *ced) |
| +{ |
| + struct em_sti_priv *p = ced_to_em_sti(ced); |
| + |
| + /* deal with old setting first */ |
| + switch (ced->mode) { |
| + case CLOCK_EVT_MODE_PERIODIC: |
| + case CLOCK_EVT_MODE_ONESHOT: |
| + em_sti_stop(p, USER_CLOCKEVENT); |
| + break; |
| + default: |
| + break; |
| + } |
| + |
| + switch (mode) { |
| + case CLOCK_EVT_MODE_PERIODIC: |
| + dev_info(&p->pdev->dev, "used for periodic clock events\n"); |
| + em_sti_start(p, USER_CLOCKEVENT); |
| + clockevents_config(&p->ced, p->rate); |
| + p->delta = (p->rate + HZ/2) / HZ; |
| + p->next = em_sti_count(p); |
| + em_sti_update(p); |
| + break; |
| + case CLOCK_EVT_MODE_ONESHOT: |
| + dev_info(&p->pdev->dev, "used for oneshot clock events\n"); |
| + em_sti_start(p, USER_CLOCKEVENT); |
| + clockevents_config(&p->ced, p->rate); |
| + break; |
| + case CLOCK_EVT_MODE_SHUTDOWN: |
| + case CLOCK_EVT_MODE_UNUSED: |
| + em_sti_stop(p, USER_CLOCKEVENT); |
| + break; |
| + default: |
| + break; |
| + } |
| +} |
| + |
| +static int em_sti_clock_event_next(unsigned long delta, |
| + struct clock_event_device *ced) |
| +{ |
| + struct em_sti_priv *p = ced_to_em_sti(ced); |
| + int safe; |
| + |
| + p->delta = delta; |
| + p->next = em_sti_count(p); |
| + em_sti_update(p); |
| + |
| + safe = em_sti_count(p) < (p->next - 1); |
| + |
| + return !safe; |
| +} |
| + |
| +static void em_sti_register_clockevent(struct em_sti_priv *p) |
| +{ |
| + struct clock_event_device *ced = &p->ced; |
| + |
| + memset(ced, 0, sizeof(*ced)); |
| + ced->name = dev_name(&p->pdev->dev); |
| + ced->features = CLOCK_EVT_FEAT_PERIODIC; |
| + ced->features |= CLOCK_EVT_FEAT_ONESHOT; |
| + ced->rating = 200; |
| + ced->cpumask = cpumask_of(0); |
| + ced->set_next_event = em_sti_clock_event_next; |
| + ced->set_mode = em_sti_clock_event_mode; |
| + |
| + dev_info(&p->pdev->dev, "used for clock events\n"); |
| + |
| + /* Register with dummy 1 Hz value, gets updated in ->set_mode() */ |
| + clockevents_config_and_register(ced, 1, 2, 0xffffffff); |
| +} |
| + |
| +static int __devinit em_sti_probe(struct platform_device *pdev) |
| +{ |
| + struct em_sti_priv *p; |
| + struct resource *res; |
| + int irq, ret; |
| + |
| + p = kzalloc(sizeof(*p), GFP_KERNEL); |
| + if (p == NULL) { |
| + dev_err(&pdev->dev, "failed to allocate driver data\n"); |
| + ret = -ENOMEM; |
| + goto err0; |
| + } |
| + |
| + p->pdev = pdev; |
| + platform_set_drvdata(pdev, p); |
| + |
| + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); |
| + if (!res) { |
| + dev_err(&pdev->dev, "failed to get I/O memory\n"); |
| + ret = -EINVAL; |
| + goto err0; |
| + } |
| + |
| + irq = platform_get_irq(pdev, 0); |
| + if (irq < 0) { |
| + dev_err(&pdev->dev, "failed to get irq\n"); |
| + ret = -EINVAL; |
| + goto err0; |
| + } |
| + |
| + /* map memory, let base point to the STI instance */ |
| + p->base = ioremap_nocache(res->start, resource_size(res)); |
| + if (p->base == NULL) { |
| + dev_err(&pdev->dev, "failed to remap I/O memory\n"); |
| + ret = -ENXIO; |
| + goto err0; |
| + } |
| + |
| + /* get hold of clock */ |
| + p->clk = clk_get(&pdev->dev, "sclk"); |
| + if (IS_ERR(p->clk)) { |
| + dev_err(&pdev->dev, "cannot get clock\n"); |
| + ret = PTR_ERR(p->clk); |
| + goto err1; |
| + } |
| + |
| + if (request_irq(irq, em_sti_interrupt, |
| + IRQF_TIMER | IRQF_IRQPOLL | IRQF_NOBALANCING, |
| + dev_name(&pdev->dev), p)) { |
| + dev_err(&pdev->dev, "failed to request low IRQ\n"); |
| + ret = -ENOENT; |
| + goto err2; |
| + } |
| + |
| + spin_lock_init(&p->lock); |
| + em_sti_register_clockevent(p); |
| + em_sti_register_clocksource(p); |
| + return 0; |
| + |
| +err2: |
| + clk_put(p->clk); |
| +err1: |
| + iounmap(p->base); |
| +err0: |
| + kfree(p); |
| + return ret; |
| +} |
| + |
| +static int __devexit em_sti_remove(struct platform_device *pdev) |
| +{ |
| + return -EBUSY; /* cannot unregister clockevent and clocksource */ |
| +} |
| + |
| +static struct platform_driver em_sti_device_driver = { |
| + .probe = em_sti_probe, |
| + .remove = __devexit_p(em_sti_remove), |
| + .driver = { |
| + .name = "em_sti", |
| + } |
| +}; |
| + |
| +module_platform_driver(em_sti_device_driver); |
| + |
| +MODULE_AUTHOR("Magnus Damm"); |
| +MODULE_DESCRIPTION("Renesas Emma Mobile STI Timer Driver"); |
| +MODULE_LICENSE("GPL v2"); |
| -- |
| 1.7.10.1.362.g242cab3 |
| |