diff options
Diffstat (limited to 'drivers/clocksource/h8300_timer16.c')
| -rw-r--r-- | drivers/clocksource/h8300_timer16.c | 254 |
1 files changed, 254 insertions, 0 deletions
diff --git a/drivers/clocksource/h8300_timer16.c b/drivers/clocksource/h8300_timer16.c new file mode 100644 index 000000000000..82941c1e9e33 --- /dev/null +++ b/drivers/clocksource/h8300_timer16.c @@ -0,0 +1,254 @@ +/* + * H8/300 16bit Timer driver + * + * Copyright 2015 Yoshinori Sato <ysato@users.sourcefoge.jp> + */ + +#include <linux/errno.h> +#include <linux/kernel.h> +#include <linux/param.h> +#include <linux/string.h> +#include <linux/slab.h> +#include <linux/interrupt.h> +#include <linux/init.h> +#include <linux/platform_device.h> +#include <linux/clocksource.h> +#include <linux/module.h> +#include <linux/clk.h> +#include <linux/io.h> +#include <linux/of.h> + +#include <asm/segment.h> +#include <asm/irq.h> + +#define TSTR 0 +#define TSNC 1 +#define TMDR 2 +#define TOLR 3 +#define TISRA 4 +#define TISRB 5 +#define TISRC 6 + +#define TCR 0 +#define TIOR 1 +#define TCNT 2 +#define GRA 4 +#define GRB 6 + +#define FLAG_REPROGRAM (1 << 0) +#define FLAG_SKIPEVENT (1 << 1) +#define FLAG_IRQCONTEXT (1 << 2) +#define FLAG_STARTED (1 << 3) + +#define ONESHOT 0 +#define PERIODIC 1 + +#define RELATIVE 0 +#define ABSOLUTE 1 + +struct timer16_priv { + struct platform_device *pdev; + struct clocksource cs; + struct irqaction irqaction; + unsigned long total_cycles; + unsigned long mapbase; + unsigned long mapcommon; + unsigned long flags; + unsigned short gra; + unsigned short cs_enabled; + unsigned char enb; + unsigned char imfa; + unsigned char imiea; + unsigned char ovf; + raw_spinlock_t lock; + struct clk *clk; +}; + +static unsigned long timer16_get_counter(struct timer16_priv *p) +{ + unsigned long v1, v2, v3; + int o1, o2; + + o1 = ctrl_inb(p->mapcommon + TISRC) & p->ovf; + + /* Make sure the timer value is stable. Stolen from acpi_pm.c */ + do { + o2 = o1; + v1 = ctrl_inw(p->mapbase + TCNT); + v2 = ctrl_inw(p->mapbase + TCNT); + v3 = ctrl_inw(p->mapbase + TCNT); + o1 = ctrl_inb(p->mapcommon + TISRC) & p->ovf; + } while (unlikely((o1 != o2) || (v1 > v2 && v1 < v3) + || (v2 > v3 && v2 < v1) || (v3 > v1 && v3 < v2))); + + v2 |= 0x10000; + return v2; +} + + +static irqreturn_t timer16_interrupt(int irq, void *dev_id) +{ + struct timer16_priv *p = (struct timer16_priv *)dev_id; + + ctrl_outb(ctrl_inb(p->mapcommon + TISRA) & ~p->imfa, + p->mapcommon + TISRA); + p->total_cycles += 0x10000; + + return IRQ_HANDLED; +} + +static inline struct timer16_priv *cs_to_priv(struct clocksource *cs) +{ + return container_of(cs, struct timer16_priv, cs); +} + +static cycle_t timer16_clocksource_read(struct clocksource *cs) +{ + struct timer16_priv *p = cs_to_priv(cs); + unsigned long flags, raw; + unsigned long value; + + raw_spin_lock_irqsave(&p->lock, flags); + value = p->total_cycles; + raw = timer16_get_counter(p); + raw_spin_unlock_irqrestore(&p->lock, flags); + + return value + raw; +} + +static int timer16_enable(struct clocksource *cs) +{ + struct timer16_priv *p = cs_to_priv(cs); + + WARN_ON(p->cs_enabled); + + p->total_cycles = 0; + ctrl_outw(0x0000, p->mapbase + TCNT); + ctrl_outb(0x83, p->mapbase + TCR); + ctrl_outb(ctrl_inb(p->mapcommon + TSTR) | p->enb, + p->mapcommon + TSTR); + + p->cs_enabled = true; + return 0; +} + +static void timer16_disable(struct clocksource *cs) +{ + struct timer16_priv *p = cs_to_priv(cs); + + WARN_ON(!p->cs_enabled); + + ctrl_outb(ctrl_inb(p->mapcommon + TSTR) & ~p->enb, + p->mapcommon + TSTR); + + p->cs_enabled = false; +} + +#define REG_CH 0 +#define REG_COMM 1 + +static int timer16_setup(struct timer16_priv *p, struct platform_device *pdev) +{ + struct resource *res[2]; + int ret, irq; + unsigned int ch; + + memset(p, 0, sizeof(*p)); + p->pdev = pdev; + + res[REG_CH] = platform_get_resource(p->pdev, + IORESOURCE_MEM, REG_CH); + res[REG_COMM] = platform_get_resource(p->pdev, + IORESOURCE_MEM, REG_COMM); + if (!res[REG_CH] || !res[REG_COMM]) { + dev_err(&p->pdev->dev, "failed to get I/O memory\n"); + return -ENXIO; + } + irq = platform_get_irq(p->pdev, 0); + if (irq < 0) { + dev_err(&p->pdev->dev, "failed to get irq\n"); + return irq; + } + + p->clk = clk_get(&p->pdev->dev, "fck"); + if (IS_ERR(p->clk)) { + dev_err(&p->pdev->dev, "can't get clk\n"); + return PTR_ERR(p->clk); + } + of_property_read_u32(p->pdev->dev.of_node, "renesas,channel", &ch); + + p->pdev = pdev; + p->mapbase = res[REG_CH]->start; + p->mapcommon = res[REG_COMM]->start; + p->enb = 1 << ch; + p->imfa = 1 << ch; + p->imiea = 1 << (4 + ch); + p->cs.name = pdev->name; + p->cs.rating = 200; + p->cs.read = timer16_clocksource_read; + p->cs.enable = timer16_enable; + p->cs.disable = timer16_disable; + p->cs.mask = CLOCKSOURCE_MASK(sizeof(unsigned long) * 8); + p->cs.flags = CLOCK_SOURCE_IS_CONTINUOUS; + + ret = request_irq(irq, timer16_interrupt, + IRQF_TIMER, pdev->name, p); + if (ret < 0) { + dev_err(&p->pdev->dev, "failed to request irq %d\n", irq); + return ret; + } + + clocksource_register_hz(&p->cs, clk_get_rate(p->clk) / 8); + + return 0; +} + +static int timer16_probe(struct platform_device *pdev) +{ + struct timer16_priv *p = platform_get_drvdata(pdev); + + if (p) { + dev_info(&pdev->dev, "kept as earlytimer\n"); + return 0; + } + + p = devm_kzalloc(&pdev->dev, sizeof(*p), GFP_KERNEL); + if (!p) + return -ENOMEM; + + return timer16_setup(p, pdev); +} + +static int timer16_remove(struct platform_device *pdev) +{ + return -EBUSY; +} + +static const struct of_device_id timer16_of_table[] = { + { .compatible = "renesas,16bit-timer" }, + { } +}; +static struct platform_driver timer16_driver = { + .probe = timer16_probe, + .remove = timer16_remove, + .driver = { + .name = "h8300h-16timer", + .of_match_table = of_match_ptr(timer16_of_table), + } +}; + +static int __init timer16_init(void) +{ + return platform_driver_register(&timer16_driver); +} + +static void __exit timer16_exit(void) +{ + platform_driver_unregister(&timer16_driver); +} + +subsys_initcall(timer16_init); +module_exit(timer16_exit); +MODULE_AUTHOR("Yoshinori Sato"); +MODULE_DESCRIPTION("H8/300H 16bit Timer Driver"); +MODULE_LICENSE("GPL v2"); |