diff options
Diffstat (limited to 'drivers/clocksource/h8300_timer8.c')
| -rw-r--r-- | drivers/clocksource/h8300_timer8.c | 211 |
1 files changed, 211 insertions, 0 deletions
diff --git a/drivers/clocksource/h8300_timer8.c b/drivers/clocksource/h8300_timer8.c new file mode 100644 index 000000000..47114c2a7 --- /dev/null +++ b/drivers/clocksource/h8300_timer8.c @@ -0,0 +1,211 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * linux/arch/h8300/kernel/cpu/timer/timer8.c + * + * Yoshinori Sato <ysato@users.sourcefoge.jp> + * + * 8bit Timer driver + * + */ + +#include <linux/errno.h> +#include <linux/kernel.h> +#include <linux/interrupt.h> +#include <linux/init.h> +#include <linux/clockchips.h> +#include <linux/clk.h> +#include <linux/io.h> +#include <linux/of.h> +#include <linux/of_address.h> +#include <linux/of_irq.h> + +#define _8TCR 0 +#define _8TCSR 2 +#define TCORA 4 +#define TCORB 6 +#define _8TCNT 8 + +#define CMIEA 6 +#define CMFA 6 + +#define FLAG_STARTED (1 << 3) + +#define SCALE 64 + +#define bset(b, a) iowrite8(ioread8(a) | (1 << (b)), (a)) +#define bclr(b, a) iowrite8(ioread8(a) & ~(1 << (b)), (a)) + +struct timer8_priv { + struct clock_event_device ced; + void __iomem *mapbase; + unsigned long flags; + unsigned int rate; +}; + +static irqreturn_t timer8_interrupt(int irq, void *dev_id) +{ + struct timer8_priv *p = dev_id; + + if (clockevent_state_oneshot(&p->ced)) + iowrite16be(0x0000, p->mapbase + _8TCR); + + p->ced.event_handler(&p->ced); + + bclr(CMFA, p->mapbase + _8TCSR); + + return IRQ_HANDLED; +} + +static void timer8_set_next(struct timer8_priv *p, unsigned long delta) +{ + if (delta >= 0x10000) + pr_warn("delta out of range\n"); + bclr(CMIEA, p->mapbase + _8TCR); + iowrite16be(delta, p->mapbase + TCORA); + iowrite16be(0x0000, p->mapbase + _8TCNT); + bclr(CMFA, p->mapbase + _8TCSR); + bset(CMIEA, p->mapbase + _8TCR); +} + +static int timer8_enable(struct timer8_priv *p) +{ + iowrite16be(0xffff, p->mapbase + TCORA); + iowrite16be(0x0000, p->mapbase + _8TCNT); + iowrite16be(0x0c02, p->mapbase + _8TCR); + + return 0; +} + +static int timer8_start(struct timer8_priv *p) +{ + int ret; + + if ((p->flags & FLAG_STARTED)) + return 0; + + ret = timer8_enable(p); + if (!ret) + p->flags |= FLAG_STARTED; + + return ret; +} + +static void timer8_stop(struct timer8_priv *p) +{ + iowrite16be(0x0000, p->mapbase + _8TCR); +} + +static inline struct timer8_priv *ced_to_priv(struct clock_event_device *ced) +{ + return container_of(ced, struct timer8_priv, ced); +} + +static void timer8_clock_event_start(struct timer8_priv *p, unsigned long delta) +{ + timer8_start(p); + timer8_set_next(p, delta); +} + +static int timer8_clock_event_shutdown(struct clock_event_device *ced) +{ + timer8_stop(ced_to_priv(ced)); + return 0; +} + +static int timer8_clock_event_periodic(struct clock_event_device *ced) +{ + struct timer8_priv *p = ced_to_priv(ced); + + pr_info("%s: used for periodic clock events\n", ced->name); + timer8_stop(p); + timer8_clock_event_start(p, (p->rate + HZ/2) / HZ); + + return 0; +} + +static int timer8_clock_event_oneshot(struct clock_event_device *ced) +{ + struct timer8_priv *p = ced_to_priv(ced); + + pr_info("%s: used for oneshot clock events\n", ced->name); + timer8_stop(p); + timer8_clock_event_start(p, 0x10000); + + return 0; +} + +static int timer8_clock_event_next(unsigned long delta, + struct clock_event_device *ced) +{ + struct timer8_priv *p = ced_to_priv(ced); + + BUG_ON(!clockevent_state_oneshot(ced)); + timer8_set_next(p, delta - 1); + + return 0; +} + +static struct timer8_priv timer8_priv = { + .ced = { + .name = "h8300_8timer", + .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT, + .rating = 200, + .set_next_event = timer8_clock_event_next, + .set_state_shutdown = timer8_clock_event_shutdown, + .set_state_periodic = timer8_clock_event_periodic, + .set_state_oneshot = timer8_clock_event_oneshot, + }, +}; + +static int __init h8300_8timer_init(struct device_node *node) +{ + void __iomem *base; + int irq, ret; + struct clk *clk; + + clk = of_clk_get(node, 0); + if (IS_ERR(clk)) { + pr_err("failed to get clock for clockevent\n"); + return PTR_ERR(clk); + } + + ret = -ENXIO; + base = of_iomap(node, 0); + if (!base) { + pr_err("failed to map registers for clockevent\n"); + goto free_clk; + } + + ret = -EINVAL; + irq = irq_of_parse_and_map(node, 0); + if (!irq) { + pr_err("failed to get irq for clockevent\n"); + goto unmap_reg; + } + + timer8_priv.mapbase = base; + + timer8_priv.rate = clk_get_rate(clk) / SCALE; + if (!timer8_priv.rate) { + pr_err("Failed to get rate for the clocksource\n"); + goto unmap_reg; + } + + if (request_irq(irq, timer8_interrupt, IRQF_TIMER, + timer8_priv.ced.name, &timer8_priv) < 0) { + pr_err("failed to request irq %d for clockevent\n", irq); + goto unmap_reg; + } + + clockevents_config_and_register(&timer8_priv.ced, + timer8_priv.rate, 1, 0x0000ffff); + + return 0; +unmap_reg: + iounmap(base); +free_clk: + clk_put(clk); + return ret; +} + +TIMER_OF_DECLARE(h8300_8bit, "renesas,8bit-timer", h8300_8timer_init); |