| /* |
| * 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; |
| raw_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; |
| } |
| |
| /* 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 u64 em_sti_count(struct em_sti_priv *p) |
| { |
| u64 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. |
| */ |
| raw_spin_lock_irqsave(&p->lock, flags); |
| ticks = (u64)(em_sti_read(p, STI_COUNT_H) & 0xffff) << 32; |
| ticks |= em_sti_read(p, STI_COUNT_L); |
| raw_spin_unlock_irqrestore(&p->lock, flags); |
| |
| return ticks; |
| } |
| |
| static u64 em_sti_set_next(struct em_sti_priv *p, u64 next) |
| { |
| unsigned long flags; |
| |
| raw_spin_lock_irqsave(&p->lock, flags); |
| |
| /* mask compare A interrupt */ |
| em_sti_write(p, STI_INTENCLR, 1); |
| |
| /* update compare A value */ |
| em_sti_write(p, STI_COMPA_H, next >> 32); |
| em_sti_write(p, STI_COMPA_L, 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); |
| |
| raw_spin_unlock_irqrestore(&p->lock, flags); |
| |
| return next; |
| } |
| |
| static irqreturn_t em_sti_interrupt(int irq, void *dev_id) |
| { |
| struct em_sti_priv *p = dev_id; |
| |
| 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; |
| |
| raw_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; |
| raw_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; |
| |
| raw_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); |
| raw_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 u64 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) |
| { |
| struct em_sti_priv *p = cs_to_em_sti(cs); |
| |
| return em_sti_start(p, USER_CLOCKSOURCE); |
| } |
| |
| 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; |
| |
| 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"); |
| |
| clocksource_register_hz(cs, p->rate); |
| 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 int em_sti_clock_event_shutdown(struct clock_event_device *ced) |
| { |
| struct em_sti_priv *p = ced_to_em_sti(ced); |
| em_sti_stop(p, USER_CLOCKEVENT); |
| return 0; |
| } |
| |
| static int em_sti_clock_event_set_oneshot(struct clock_event_device *ced) |
| { |
| struct em_sti_priv *p = ced_to_em_sti(ced); |
| |
| dev_info(&p->pdev->dev, "used for oneshot clock events\n"); |
| em_sti_start(p, USER_CLOCKEVENT); |
| return 0; |
| } |
| |
| 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); |
| u64 next; |
| int safe; |
| |
| next = em_sti_set_next(p, em_sti_count(p) + delta); |
| safe = em_sti_count(p) < (next - 1); |
| |
| return !safe; |
| } |
| |
| static void em_sti_register_clockevent(struct em_sti_priv *p) |
| { |
| struct clock_event_device *ced = &p->ced; |
| |
| ced->name = dev_name(&p->pdev->dev); |
| ced->features = CLOCK_EVT_FEAT_ONESHOT; |
| ced->rating = 200; |
| ced->cpumask = cpu_possible_mask; |
| ced->set_next_event = em_sti_clock_event_next; |
| ced->set_state_shutdown = em_sti_clock_event_shutdown; |
| ced->set_state_oneshot = em_sti_clock_event_set_oneshot; |
| |
| dev_info(&p->pdev->dev, "used for clock events\n"); |
| |
| clockevents_config_and_register(ced, p->rate, 2, 0xffffffff); |
| } |
| |
| static int em_sti_probe(struct platform_device *pdev) |
| { |
| struct em_sti_priv *p; |
| struct resource *res; |
| int irq; |
| int ret; |
| |
| p = devm_kzalloc(&pdev->dev, sizeof(*p), GFP_KERNEL); |
| if (p == NULL) |
| return -ENOMEM; |
| |
| p->pdev = pdev; |
| platform_set_drvdata(pdev, p); |
| |
| irq = platform_get_irq(pdev, 0); |
| if (irq < 0) { |
| dev_err(&pdev->dev, "failed to get irq\n"); |
| return -EINVAL; |
| } |
| |
| /* map memory, let base point to the STI instance */ |
| res = platform_get_resource(pdev, IORESOURCE_MEM, 0); |
| p->base = devm_ioremap_resource(&pdev->dev, res); |
| if (IS_ERR(p->base)) |
| return PTR_ERR(p->base); |
| |
| if (devm_request_irq(&pdev->dev, 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"); |
| return -ENOENT; |
| } |
| |
| /* get hold of clock */ |
| p->clk = devm_clk_get(&pdev->dev, "sclk"); |
| if (IS_ERR(p->clk)) { |
| dev_err(&pdev->dev, "cannot get clock\n"); |
| return PTR_ERR(p->clk); |
| } |
| |
| ret = clk_prepare(p->clk); |
| if (ret < 0) { |
| dev_err(&pdev->dev, "cannot prepare clock\n"); |
| return ret; |
| } |
| |
| ret = clk_enable(p->clk); |
| if (ret < 0) { |
| dev_err(&p->pdev->dev, "cannot enable clock\n"); |
| clk_unprepare(p->clk); |
| return ret; |
| } |
| p->rate = clk_get_rate(p->clk); |
| clk_disable(p->clk); |
| |
| raw_spin_lock_init(&p->lock); |
| em_sti_register_clockevent(p); |
| em_sti_register_clocksource(p); |
| return 0; |
| } |
| |
| static int em_sti_remove(struct platform_device *pdev) |
| { |
| return -EBUSY; /* cannot unregister clockevent and clocksource */ |
| } |
| |
| static const struct of_device_id em_sti_dt_ids[] = { |
| { .compatible = "renesas,em-sti", }, |
| {}, |
| }; |
| MODULE_DEVICE_TABLE(of, em_sti_dt_ids); |
| |
| static struct platform_driver em_sti_device_driver = { |
| .probe = em_sti_probe, |
| .remove = em_sti_remove, |
| .driver = { |
| .name = "em_sti", |
| .of_match_table = em_sti_dt_ids, |
| } |
| }; |
| |
| static int __init em_sti_init(void) |
| { |
| return platform_driver_register(&em_sti_device_driver); |
| } |
| |
| static void __exit em_sti_exit(void) |
| { |
| platform_driver_unregister(&em_sti_device_driver); |
| } |
| |
| subsys_initcall(em_sti_init); |
| module_exit(em_sti_exit); |
| |
| MODULE_AUTHOR("Magnus Damm"); |
| MODULE_DESCRIPTION("Renesas Emma Mobile STI Timer Driver"); |
| MODULE_LICENSE("GPL v2"); |